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Date:: Fri Jan 22 11:05:05 2021 UTC
Message:: make close(2) failure checks consistent; check 'close() == -1' everywhere ok millert, naddy
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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 
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <unistd.h>
33 #include <zlib.h>
34 #include <imsg.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_sha1.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_delta_cache.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.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)
73 {
74 	const struct got_error *err = NULL;
75 	struct got_packidx_v2_hdr *h;
76 	SHA1_CTX ctx;
77 	uint8_t sha1[SHA1_DIGEST_LENGTH];
78 	size_t nobj, len_fanout, len_ids, offset, remain;
79 	ssize_t n;
80 	int i;
81 
82 	SHA1Init(&ctx);
83 
84 	h = &p->hdr;
85 	offset = 0;
86 	remain = p->len;
87 
88 	if (remain < sizeof(*h->magic)) {
89 		err = got_error(GOT_ERR_BAD_PACKIDX);
90 		goto done;
91 	}
92 	if (p->map)
93 		h->magic = (uint32_t *)(p->map + offset);
94 	else {
95 		h->magic = malloc(sizeof(*h->magic));
96 		if (h->magic == NULL) {
97 			err = got_error_from_errno("malloc");
98 			goto done;
99 		}
100 		n = read(p->fd, h->magic, sizeof(*h->magic));
101 		if (n < 0) {
102 			err = got_error_from_errno("read");
103 			goto done;
104 		} else if (n != sizeof(*h->magic)) {
105 			err = got_error(GOT_ERR_BAD_PACKIDX);
106 			goto done;
107 		}
108 	}
109 	if (be32toh(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
110 		err = got_error(GOT_ERR_BAD_PACKIDX);
111 		goto done;
112 	}
113 	offset += sizeof(*h->magic);
114 	remain -= sizeof(*h->magic);
115 
116 	if (verify)
117 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
118 
119 	if (remain < sizeof(*h->version)) {
120 		err = got_error(GOT_ERR_BAD_PACKIDX);
121 		goto done;
122 	}
123 	if (p->map)
124 		h->version = (uint32_t *)(p->map + offset);
125 	else {
126 		h->version = malloc(sizeof(*h->version));
127 		if (h->version == NULL) {
128 			err = got_error_from_errno("malloc");
129 			goto done;
130 		}
131 		n = read(p->fd, h->version, sizeof(*h->version));
132 		if (n < 0) {
133 			err = got_error_from_errno("read");
134 			goto done;
135 		} else if (n != sizeof(*h->version)) {
136 			err = got_error(GOT_ERR_BAD_PACKIDX);
137 			goto done;
138 		}
139 	}
140 	if (be32toh(*h->version) != GOT_PACKIDX_VERSION) {
141 		err = got_error(GOT_ERR_BAD_PACKIDX);
142 		goto done;
143 	}
144 	offset += sizeof(*h->version);
145 	remain -= sizeof(*h->version);
146 
147 	if (verify)
148 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
149 
150 	len_fanout =
151 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
152 	if (remain < len_fanout) {
153 		err = got_error(GOT_ERR_BAD_PACKIDX);
154 		goto done;
155 	}
156 	if (p->map)
157 		h->fanout_table = (uint32_t *)(p->map + offset);
158 	else {
159 		h->fanout_table = malloc(len_fanout);
160 		if (h->fanout_table == NULL) {
161 			err = got_error_from_errno("malloc");
162 			goto done;
163 		}
164 		n = read(p->fd, h->fanout_table, len_fanout);
165 		if (n < 0) {
166 			err = got_error_from_errno("read");
167 			goto done;
168 		} else if (n != len_fanout) {
169 			err = got_error(GOT_ERR_BAD_PACKIDX);
170 			goto done;
171 		}
172 	}
173 	err = verify_fanout_table(h->fanout_table);
174 	if (err)
175 		goto done;
176 	if (verify)
177 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
178 	offset += len_fanout;
179 	remain -= len_fanout;
180 
181 	nobj = be32toh(h->fanout_table[0xff]);
182 	len_ids = nobj * sizeof(*h->sorted_ids);
183 	if (len_ids <= nobj || len_ids > remain) {
184 		err = got_error(GOT_ERR_BAD_PACKIDX);
185 		goto done;
186 	}
187 	if (p->map)
188 		h->sorted_ids =
189 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
190 	else {
191 		h->sorted_ids = malloc(len_ids);
192 		if (h->sorted_ids == NULL) {
193 			err = got_error(GOT_ERR_BAD_PACKIDX);
194 			goto done;
195 		}
196 		n = read(p->fd, h->sorted_ids, len_ids);
197 		if (n < 0)
198 			err = got_error_from_errno("read");
199 		else if (n != len_ids) {
200 			err = got_error(GOT_ERR_BAD_PACKIDX);
201 			goto done;
202 		}
203 	}
204 	if (verify)
205 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
206 	offset += len_ids;
207 	remain -= len_ids;
208 
209 	if (remain < nobj * sizeof(*h->crc32)) {
210 		err = got_error(GOT_ERR_BAD_PACKIDX);
211 		goto done;
212 	}
213 	if (p->map)
214 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
215 	else {
216 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
217 		if (h->crc32 == NULL) {
218 			err = got_error_from_errno("malloc");
219 			goto done;
220 		}
221 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
222 		if (n < 0)
223 			err = got_error_from_errno("read");
224 		else if (n != nobj * sizeof(*h->crc32)) {
225 			err = got_error(GOT_ERR_BAD_PACKIDX);
226 			goto done;
227 		}
228 	}
229 	if (verify)
230 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
231 	remain -= nobj * sizeof(*h->crc32);
232 	offset += nobj * sizeof(*h->crc32);
233 
234 	if (remain < nobj * sizeof(*h->offsets)) {
235 		err = got_error(GOT_ERR_BAD_PACKIDX);
236 		goto done;
237 	}
238 	if (p->map)
239 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
240 	else {
241 		h->offsets = malloc(nobj * sizeof(*h->offsets));
242 		if (h->offsets == NULL) {
243 			err = got_error_from_errno("malloc");
244 			goto done;
245 		}
246 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
247 		if (n < 0)
248 			err = got_error_from_errno("read");
249 		else if (n != nobj * sizeof(*h->offsets)) {
250 			err = got_error(GOT_ERR_BAD_PACKIDX);
251 			goto done;
252 		}
253 	}
254 	if (verify)
255 		SHA1Update(&ctx, (uint8_t *)h->offsets,
256 		    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 	for (i = 0; i < nobj; i++) {
262 		uint32_t o = be32toh(h->offsets[i]);
263 		if (o & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX)
264 			p->nlargeobj++;
265 	}
266 	if (p->nlargeobj == 0)
267 		goto checksum;
268 
269 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
270 		err = got_error(GOT_ERR_BAD_PACKIDX);
271 		goto done;
272 	}
273 	if (p->map)
274 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
275 	else {
276 		h->large_offsets = malloc(p->nlargeobj *
277 		    sizeof(*h->large_offsets));
278 		if (h->large_offsets == NULL) {
279 			err = got_error_from_errno("malloc");
280 			goto done;
281 		}
282 		n = read(p->fd, h->large_offsets,
283 		    p->nlargeobj * sizeof(*h->large_offsets));
284 		if (n < 0)
285 			err = got_error_from_errno("read");
286 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
287 			err = got_error(GOT_ERR_BAD_PACKIDX);
288 			goto done;
289 		}
290 	}
291 	if (verify)
292 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
293 		    p->nlargeobj * sizeof(*h->large_offsets));
294 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
295 	offset += p->nlargeobj * sizeof(*h->large_offsets);
296 
297 checksum:
298 	if (remain < sizeof(*h->trailer)) {
299 		err = got_error(GOT_ERR_BAD_PACKIDX);
300 		goto done;
301 	}
302 	if (p->map)
303 		h->trailer =
304 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
305 	else {
306 		h->trailer = malloc(sizeof(*h->trailer));
307 		if (h->trailer == NULL) {
308 			err = got_error_from_errno("malloc");
309 			goto done;
310 		}
311 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
312 		if (n < 0)
313 			err = got_error_from_errno("read");
314 		else if (n != sizeof(*h->trailer)) {
315 			err = got_error(GOT_ERR_BAD_PACKIDX);
316 			goto done;
317 		}
318 	}
319 	if (verify) {
320 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
321 		SHA1Final(sha1, &ctx);
322 		if (memcmp(h->trailer->packidx_sha1, sha1,
323 		    SHA1_DIGEST_LENGTH) != 0)
324 			err = got_error(GOT_ERR_PACKIDX_CSUM);
325 	}
326 done:
327 	return err;
328 }
329 
330 const struct got_error *
331 got_packidx_open(struct got_packidx **packidx,
332     int dir_fd, const char *relpath, int verify)
333 {
334 	const struct got_error *err = NULL;
335 	struct got_packidx *p;
336 	struct stat sb;
337 
338 	*packidx = NULL;
339 
340 	p = calloc(1, sizeof(*p));
341 	if (p == NULL)
342 		return got_error_from_errno("calloc");
343 
344 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW);
345 	if (p->fd == -1) {
346 		err = got_error_from_errno2("openat", relpath);
347 		free(p);
348 		return err;
349 	}
350 
351 	if (fstat(p->fd, &sb) != 0) {
352 		err = got_error_from_errno2("fstat", relpath);
353 		close(p->fd);
354 		free(p);
355 		return err;
356 	}
357 	p->len = sb.st_size;
358 	if (p->len < sizeof(p->hdr)) {
359 		err = got_error(GOT_ERR_BAD_PACKIDX);
360 		close(p->fd);
361 		free(p);
362 		return err;
363 	}
364 
365 	p->path_packidx = strdup(relpath);
366 	if (p->path_packidx == NULL) {
367 		err = got_error_from_errno("strdup");
368 		goto done;
369 	}
370 
371 #ifndef GOT_PACK_NO_MMAP
372 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
373 	if (p->map == MAP_FAILED) {
374 		if (errno != ENOMEM) {
375 			err = got_error_from_errno("mmap");
376 			goto done;
377 		}
378 		p->map = NULL; /* fall back to read(2) */
379 	}
380 #endif
381 
382 	err = got_packidx_init_hdr(p, verify);
383 done:
384 	if (err)
385 		got_packidx_close(p);
386 	else
387 		*packidx = p;
388 
389 	return err;
390 }
391 
392 const struct got_error *
393 got_packidx_close(struct got_packidx *packidx)
394 {
395 	const struct got_error *err = NULL;
396 
397 	free(packidx->path_packidx);
398 	if (packidx->map) {
399 		if (munmap(packidx->map, packidx->len) == -1)
400 			err = got_error_from_errno("munmap");
401 	} else {
402 		free(packidx->hdr.magic);
403 		free(packidx->hdr.version);
404 		free(packidx->hdr.fanout_table);
405 		free(packidx->hdr.sorted_ids);
406 		free(packidx->hdr.crc32);
407 		free(packidx->hdr.offsets);
408 		free(packidx->hdr.large_offsets);
409 		free(packidx->hdr.trailer);
410 	}
411 	if (close(packidx->fd) == -1 && err == NULL)
412 		err = got_error_from_errno("close");
413 	free(packidx);
414 
415 	return err;
416 }
417 
418 static off_t
419 get_object_offset(struct got_packidx *packidx, int idx)
420 {
421 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
422 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
423 		uint64_t loffset;
424 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
425 		if (idx < 0 || idx >= packidx->nlargeobj ||
426 		    packidx->hdr.large_offsets == NULL)
427 			return -1;
428 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
429 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
430 	}
431 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
432 }
433 
434 int
435 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
436 {
437 	u_int8_t id0 = id->sha1[0];
438 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
439 	int left = 0, right = totobj - 1;
440 
441 	if (id0 > 0)
442 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
443 
444 	while (left <= right) {
445 		struct got_packidx_object_id *oid;
446 		int i, cmp;
447 
448 		i = ((left + right) / 2);
449 		oid = &packidx->hdr.sorted_ids[i];
450 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
451 		if (cmp == 0)
452 			return i;
453 		else if (cmp > 0)
454 			left = i + 1;
455 		else if (cmp < 0)
456 			right = i - 1;
457 	}
458 
459 	return -1;
460 }
461 
462 const struct got_error *
463 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
464     struct got_packidx *packidx, const char *id_str_prefix)
465 {
466 	const struct got_error *err = NULL;
467 	u_int8_t id0;
468 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
469 	char hex[3];
470 	size_t prefix_len = strlen(id_str_prefix);
471 	struct got_packidx_object_id *oid;
472 	uint32_t i;
473 
474 	SIMPLEQ_INIT(matched_ids);
475 
476 	if (prefix_len < 2)
477 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
478 
479 	hex[0] = id_str_prefix[0];
480 	hex[1] = id_str_prefix[1];
481 	hex[2] = '\0';
482 	if (!got_parse_xdigit(&id0, hex))
483 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
484 
485 	i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
486 	oid = &packidx->hdr.sorted_ids[i];
487 	while (i < totobj && oid->sha1[0] == id0) {
488 		char id_str[SHA1_DIGEST_STRING_LENGTH];
489 		struct got_object_qid *qid;
490 		int cmp;
491 
492 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
493 		        return got_error(GOT_ERR_NO_SPACE);
494 
495 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
496 		if (cmp < 0) {
497 			oid = &packidx->hdr.sorted_ids[++i];
498 			continue;
499 		} else if (cmp > 0)
500 			break;
501 
502 		err = got_object_qid_alloc_partial(&qid);
503 		if (err)
504 			break;
505 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
506 		SIMPLEQ_INSERT_TAIL(matched_ids, qid, entry);
507 
508 		oid = &packidx->hdr.sorted_ids[++i];
509 	}
510 
511 	if (err)
512 		got_object_id_queue_free(matched_ids);
513 	return err;
514 }
515 
516 const struct got_error *
517 got_pack_stop_privsep_child(struct got_pack *pack)
518 {
519 	const struct got_error *err = NULL;
520 
521 	if (pack->privsep_child == NULL)
522 		return NULL;
523 
524 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
525 	if (err)
526 		return err;
527 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
528 	if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
529 		err = got_error_from_errno("close");
530 	free(pack->privsep_child);
531 	pack->privsep_child = NULL;
532 	return err;
533 }
534 
535 const struct got_error *
536 got_pack_close(struct got_pack *pack)
537 {
538 	const struct got_error *err = NULL;
539 
540 	err = got_pack_stop_privsep_child(pack);
541 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
542 		err = got_error_from_errno("munmap");
543 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
544 		err = got_error_from_errno("close");
545 	pack->fd = -1;
546 	free(pack->path_packfile);
547 	pack->path_packfile = NULL;
548 	pack->filesize = 0;
549 	if (pack->delta_cache) {
550 		got_delta_cache_free(pack->delta_cache);
551 		pack->delta_cache = NULL;
552 	}
553 
554 	return err;
555 }
556 
557 const struct got_error *
558 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
559     struct got_pack *pack, off_t offset)
560 {
561 	uint8_t t = 0;
562 	uint64_t s = 0;
563 	uint8_t sizeN;
564 	size_t mapoff = 0;
565 	int i = 0;
566 
567 	*len = 0;
568 
569 	if (offset >= pack->filesize)
570 		return got_error(GOT_ERR_PACK_OFFSET);
571 
572 	if (pack->map) {
573 		mapoff = (size_t)offset;
574 	} else {
575 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
576 			return got_error_from_errno("lseek");
577 	}
578 
579 	do {
580 		/* We do not support size values which don't fit in 64 bit. */
581 		if (i > 9)
582 			return got_error(GOT_ERR_NO_SPACE);
583 
584 		if (pack->map) {
585 			sizeN = *(pack->map + mapoff);
586 			mapoff += sizeof(sizeN);
587 		} else {
588 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
589 			if (n < 0)
590 				return got_error_from_errno("read");
591 			if (n != sizeof(sizeN))
592 				return got_error(GOT_ERR_BAD_PACKFILE);
593 		}
594 		*len += sizeof(sizeN);
595 
596 		if (i == 0) {
597 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
598 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
599 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
600 		} else {
601 			size_t shift = 4 + 7 * (i - 1);
602 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
603 		}
604 		i++;
605 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
606 
607 	*type = t;
608 	*size = s;
609 	return NULL;
610 }
611 
612 static const struct got_error *
613 open_plain_object(struct got_object **obj, struct got_object_id *id,
614     uint8_t type, off_t offset, size_t size, int idx)
615 {
616 	*obj = calloc(1, sizeof(**obj));
617 	if (*obj == NULL)
618 		return got_error_from_errno("calloc");
619 
620 	(*obj)->type = type;
621 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
622 	(*obj)->pack_idx = idx;
623 	(*obj)->hdrlen = 0;
624 	(*obj)->size = size;
625 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
626 	(*obj)->pack_offset = offset;
627 
628 	return NULL;
629 }
630 
631 static const struct got_error *
632 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
633     off_t delta_offset)
634 {
635 	int64_t o = 0;
636 	uint8_t offN;
637 	int i = 0;
638 
639 	*offset = 0;
640 	*len = 0;
641 
642 	do {
643 		/* We do not support offset values which don't fit in 64 bit. */
644 		if (i > 8)
645 			return got_error(GOT_ERR_NO_SPACE);
646 
647 		if (pack->map) {
648 			size_t mapoff;
649 			if (delta_offset >= pack->filesize)
650 				return got_error(GOT_ERR_PACK_OFFSET);
651 			mapoff = (size_t)delta_offset + *len;
652 			offN = *(pack->map + mapoff);
653 		} else {
654 			ssize_t n;
655 			n = read(pack->fd, &offN, sizeof(offN));
656 			if (n < 0)
657 				return got_error_from_errno("read");
658 			if (n != sizeof(offN))
659 				return got_error(GOT_ERR_BAD_PACKFILE);
660 		}
661 		*len += sizeof(offN);
662 
663 		if (i == 0)
664 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
665 		else {
666 			o++;
667 			o <<= 7;
668 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
669 		}
670 		i++;
671 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
672 
673 	*offset = o;
674 	return NULL;
675 }
676 
677 const struct got_error *
678 got_pack_parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
679     off_t offset, int tslen)
680 {
681 	const struct got_error *err;
682 	int64_t negoffset;
683 	size_t negofflen;
684 
685 	*len = 0;
686 
687 	err = parse_negative_offset(&negoffset, &negofflen, pack,
688 	    offset + tslen);
689 	if (err)
690 		return err;
691 
692 	/* Compute the base object's offset (must be in the same pack file). */
693 	*base_offset = (offset - negoffset);
694 	if (*base_offset <= 0)
695 		return got_error(GOT_ERR_BAD_PACKFILE);
696 
697 	*len = negofflen;
698 	return NULL;
699 }
700 
701 static const struct got_error *
702 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
703     size_t delta_data_offset, struct got_pack *pack)
704 {
705 	const struct got_error *err = NULL;
706 
707 	if (pack->map) {
708 		if (delta_data_offset >= pack->filesize)
709 			return got_error(GOT_ERR_PACK_OFFSET);
710 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
711 		    NULL, NULL, pack->map, delta_data_offset,
712 		    pack->filesize - delta_data_offset);
713 	} else {
714 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
715 			return got_error_from_errno("lseek");
716 		err = got_inflate_to_mem_fd(delta_buf, delta_len, NULL,
717 		    NULL, 0, pack->fd);
718 	}
719 	return err;
720 }
721 
722 static const struct got_error *
723 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
724     int delta_type, size_t delta_size, size_t delta_data_offset)
725 {
726 	struct got_delta *delta;
727 
728 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
729 	    delta_data_offset);
730 	if (delta == NULL)
731 		return got_error_from_errno("got_delta_open");
732 	/* delta is freed in got_object_close() */
733 	deltas->nentries++;
734 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
735 	return NULL;
736 }
737 
738 static const struct got_error *
739 resolve_offset_delta(struct got_delta_chain *deltas,
740     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
741     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
742 
743 {
744 	const struct got_error *err;
745 	off_t base_offset;
746 	uint8_t base_type;
747 	uint64_t base_size;
748 	size_t base_tslen;
749 	off_t delta_data_offset;
750 	size_t consumed;
751 
752 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
753 	    delta_offset, tslen);
754 	if (err)
755 		return err;
756 
757 	delta_data_offset = delta_offset + tslen + consumed;
758 	if (delta_data_offset >= pack->filesize)
759 		return got_error(GOT_ERR_PACK_OFFSET);
760 
761 	if (pack->map == NULL) {
762 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
763 		if (delta_data_offset == -1)
764 			return got_error_from_errno("lseek");
765 	}
766 
767 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
768 	    delta_data_offset);
769 	if (err)
770 		return err;
771 
772 	/* An offset delta must be in the same packfile. */
773 	if (base_offset >= pack->filesize)
774 		return got_error(GOT_ERR_PACK_OFFSET);
775 
776 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
777 	    &base_tslen, pack, base_offset);
778 	if (err)
779 		return err;
780 
781 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
782 	    base_tslen, base_type, base_size, recursion - 1);
783 }
784 
785 static const struct got_error *
786 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
787     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
788     size_t delta_size, unsigned int recursion)
789 {
790 	const struct got_error *err;
791 	struct got_object_id id;
792 	int idx;
793 	off_t base_offset;
794 	uint8_t base_type;
795 	uint64_t base_size;
796 	size_t base_tslen;
797 	off_t delta_data_offset;
798 
799 	if (delta_offset + tslen >= pack->filesize)
800 		return got_error(GOT_ERR_PACK_OFFSET);
801 
802 	if (pack->map) {
803 		size_t mapoff = delta_offset + tslen;
804 		memcpy(&id, pack->map + mapoff, sizeof(id));
805 		mapoff += sizeof(id);
806 		delta_data_offset = (off_t)mapoff;
807 	} else {
808 		ssize_t n;
809 		n = read(pack->fd, &id, sizeof(id));
810 		if (n < 0)
811 			return got_error_from_errno("read");
812 		if (n != sizeof(id))
813 			return got_error(GOT_ERR_BAD_PACKFILE);
814 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
815 		if (delta_data_offset == -1)
816 			return got_error_from_errno("lseek");
817 	}
818 
819 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
820 	    delta_data_offset);
821 	if (err)
822 		return err;
823 
824 	/* Delta base must be in the same pack file. */
825 	idx = got_packidx_get_object_idx(packidx, &id);
826 	if (idx == -1)
827 		return got_error(GOT_ERR_NO_OBJ);
828 
829 	base_offset = get_object_offset(packidx, idx);
830 	if (base_offset == (uint64_t)-1)
831 		return got_error(GOT_ERR_BAD_PACKIDX);
832 
833 	if (base_offset >= pack->filesize)
834 		return got_error(GOT_ERR_PACK_OFFSET);
835 
836 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
837 	    &base_tslen, pack, base_offset);
838 	if (err)
839 		return err;
840 
841 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
842 	    base_tslen, base_type, base_size, recursion - 1);
843 }
844 
845 const struct got_error *
846 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
847     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
848     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
849 {
850 	const struct got_error *err = NULL;
851 
852 	if (--recursion == 0)
853 		return got_error(GOT_ERR_RECURSION);
854 
855 	switch (delta_type) {
856 	case GOT_OBJ_TYPE_COMMIT:
857 	case GOT_OBJ_TYPE_TREE:
858 	case GOT_OBJ_TYPE_BLOB:
859 	case GOT_OBJ_TYPE_TAG:
860 		/* Plain types are the final delta base. Recursion ends. */
861 		err = add_delta(deltas, delta_offset, tslen, delta_type,
862 		    delta_size, 0);
863 		break;
864 	case GOT_OBJ_TYPE_OFFSET_DELTA:
865 		err = resolve_offset_delta(deltas, packidx, pack,
866 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
867 		break;
868 	case GOT_OBJ_TYPE_REF_DELTA:
869 		err = resolve_ref_delta(deltas, packidx, pack,
870 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
871 		break;
872 	default:
873 		return got_error(GOT_ERR_OBJ_TYPE);
874 	}
875 
876 	return err;
877 }
878 
879 static const struct got_error *
880 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
881     struct got_pack *pack, struct got_object_id *id, off_t offset,
882     size_t tslen, int delta_type, size_t delta_size, int idx)
883 {
884 	const struct got_error *err = NULL;
885 	int resolved_type;
886 
887 	*obj = calloc(1, sizeof(**obj));
888 	if (*obj == NULL)
889 		return got_error_from_errno("calloc");
890 
891 	(*obj)->flags = 0;
892 	(*obj)->hdrlen = 0;
893 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
894 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
895 	(*obj)->pack_offset = offset + tslen;
896 
897 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
898 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
899 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
900 	(*obj)->pack_idx = idx;
901 
902 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
903 	    offset, tslen, delta_type, delta_size,
904 	    GOT_DELTA_CHAIN_RECURSION_MAX);
905 	if (err)
906 		goto done;
907 
908 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
909 	if (err)
910 		goto done;
911 	(*obj)->type = resolved_type;
912 done:
913 	if (err) {
914 		got_object_close(*obj);
915 		*obj = NULL;
916 	}
917 	return err;
918 }
919 
920 const struct got_error *
921 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
922     struct got_packidx *packidx, int idx, struct got_object_id *id)
923 {
924 	const struct got_error *err = NULL;
925 	off_t offset;
926 	uint8_t type;
927 	uint64_t size;
928 	size_t tslen;
929 
930 	*obj = NULL;
931 
932 	offset = get_object_offset(packidx, idx);
933 	if (offset == (uint64_t)-1)
934 		return got_error(GOT_ERR_BAD_PACKIDX);
935 
936 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
937 	    pack, offset);
938 	if (err)
939 		return err;
940 
941 	switch (type) {
942 	case GOT_OBJ_TYPE_COMMIT:
943 	case GOT_OBJ_TYPE_TREE:
944 	case GOT_OBJ_TYPE_BLOB:
945 	case GOT_OBJ_TYPE_TAG:
946 		err = open_plain_object(obj, id, type, offset + tslen,
947 		    size, idx);
948 		break;
949 	case GOT_OBJ_TYPE_OFFSET_DELTA:
950 	case GOT_OBJ_TYPE_REF_DELTA:
951 		err = open_delta_object(obj, packidx, pack, id, offset,
952 		    tslen, type, size, idx);
953 		break;
954 	default:
955 		err = got_error(GOT_ERR_OBJ_TYPE);
956 		break;
957 	}
958 
959 	return err;
960 }
961 
962 const struct got_error *
963 got_pack_get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas,
964     struct got_pack *pack)
965 {
966 	struct got_delta *delta;
967 	uint64_t base_size = 0, result_size = 0;
968 
969 	*max_size = 0;
970 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
971 		/* Plain object types are the delta base. */
972 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
973 		    delta->type != GOT_OBJ_TYPE_TREE &&
974 		    delta->type != GOT_OBJ_TYPE_BLOB &&
975 		    delta->type != GOT_OBJ_TYPE_TAG) {
976 			const struct got_error *err;
977 			uint8_t *delta_buf;
978 			size_t delta_len;
979 			int cached = 1;
980 
981 			got_delta_cache_get(&delta_buf, &delta_len,
982 			    pack->delta_cache, delta->data_offset);
983 			if (delta_buf == NULL) {
984 				cached = 0;
985 				err = read_delta_data(&delta_buf, &delta_len,
986 				    delta->data_offset, pack);
987 				if (err)
988 					return err;
989 				err = got_delta_cache_add(pack->delta_cache,
990 				    delta->data_offset, delta_buf, delta_len);
991 				if (err == NULL)
992 					cached = 1;
993 				else if (err->code != GOT_ERR_NO_SPACE) {
994 					free(delta_buf);
995 					return err;
996 				}
997 			}
998 			err = got_delta_get_sizes(&base_size, &result_size,
999 			    delta_buf, delta_len);
1000 			if (!cached)
1001 				free(delta_buf);
1002 			if (err)
1003 				return err;
1004 		} else
1005 			base_size = delta->size;
1006 		if (base_size > *max_size)
1007 			*max_size = base_size;
1008 		if (result_size > *max_size)
1009 			*max_size = result_size;
1010 	}
1011 
1012 	return NULL;
1013 }
1014 
1015 const struct got_error *
1016 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1017     struct got_pack *pack)
1018 {
1019 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1020 		return got_error(GOT_ERR_OBJ_TYPE);
1021 
1022 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1023 }
1024 
1025 const struct got_error *
1026 got_pack_dump_delta_chain_to_file(size_t *result_size,
1027     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1028     FILE *base_file, FILE *accum_file)
1029 {
1030 	const struct got_error *err = NULL;
1031 	struct got_delta *delta;
1032 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1033 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1034 	uint64_t max_size;
1035 	int n = 0;
1036 
1037 	*result_size = 0;
1038 
1039 	if (SIMPLEQ_EMPTY(&deltas->entries))
1040 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1041 
1042 	/* We process small enough files entirely in memory for speed. */
1043 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1044 	if (err)
1045 		return err;
1046 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1047 		accum_buf = malloc(max_size);
1048 		if (accum_buf == NULL)
1049 			return got_error_from_errno("malloc");
1050 		base_file = NULL;
1051 		accum_file = NULL;
1052 	}
1053 
1054 	/* Deltas are ordered in ascending order. */
1055 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1056 		int cached = 1;
1057 		if (n == 0) {
1058 			size_t mapoff;
1059 			off_t delta_data_offset;
1060 
1061 			/* Plain object types are the delta base. */
1062 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1063 			    delta->type != GOT_OBJ_TYPE_TREE &&
1064 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1065 			    delta->type != GOT_OBJ_TYPE_TAG) {
1066 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1067 				goto done;
1068 			}
1069 
1070 			delta_data_offset = delta->offset + delta->tslen;
1071 			if (delta_data_offset >= pack->filesize) {
1072 				err = got_error(GOT_ERR_PACK_OFFSET);
1073 				goto done;
1074 			}
1075 			if (pack->map == NULL) {
1076 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1077 				    == -1) {
1078 					err = got_error_from_errno("lseek");
1079 					goto done;
1080 				}
1081 			}
1082 			if (base_file) {
1083 				if (pack->map) {
1084 					mapoff = (size_t)delta_data_offset;
1085 					err = got_inflate_to_file_mmap(
1086 					    &base_bufsz, NULL, NULL, pack->map,
1087 					    mapoff, pack->filesize - mapoff,
1088 					    base_file);
1089 				} else
1090 					err = got_inflate_to_file_fd(
1091 					    &base_bufsz, NULL, NULL, pack->fd,
1092 					    base_file);
1093 			} else {
1094 				if (pack->map) {
1095 					mapoff = (size_t)delta_data_offset;
1096 					err = got_inflate_to_mem_mmap(&base_buf,
1097 					    &base_bufsz, NULL, NULL,
1098 					    pack->map, mapoff,
1099 					    pack->filesize - mapoff);
1100 				} else
1101 					err = got_inflate_to_mem_fd(&base_buf,
1102 					    &base_bufsz, NULL, NULL, max_size,
1103 					    pack->fd);
1104 			}
1105 			if (err)
1106 				goto done;
1107 			n++;
1108 			if (base_file)
1109 				rewind(base_file);
1110 			continue;
1111 		}
1112 
1113 		got_delta_cache_get(&delta_buf, &delta_len,
1114 		    pack->delta_cache, delta->data_offset);
1115 		if (delta_buf == NULL) {
1116 			cached = 0;
1117 			err = read_delta_data(&delta_buf, &delta_len,
1118 			    delta->data_offset, pack);
1119 			if (err)
1120 				goto done;
1121 			err = got_delta_cache_add(pack->delta_cache,
1122 			    delta->data_offset, delta_buf, delta_len);
1123 			if (err == NULL)
1124 				cached = 1;
1125 			else if (err->code != GOT_ERR_NO_SPACE) {
1126 				free(delta_buf);
1127 				goto done;
1128 			}
1129 		}
1130 		if (base_buf) {
1131 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1132 			    delta_buf, delta_len, accum_buf,
1133 			    &accum_size, max_size);
1134 			n++;
1135 		} else {
1136 			err = got_delta_apply(base_file, delta_buf,
1137 			    delta_len,
1138 			    /* Final delta application writes to output file. */
1139 			    ++n < deltas->nentries ? accum_file : outfile,
1140 			    &accum_size);
1141 		}
1142 		if (!cached)
1143 			free(delta_buf);
1144 		if (err)
1145 			goto done;
1146 
1147 		if (n < deltas->nentries) {
1148 			/* Accumulated delta becomes the new base. */
1149 			if (base_buf) {
1150 				uint8_t *tmp = accum_buf;
1151 				/*
1152 				 * Base buffer switches roles with accumulation
1153 				 * buffer. Ensure it can hold the largest
1154 				 * result in the delta chain. The initial
1155 				 * allocation might have been smaller.
1156 				 */
1157 				if (base_bufsz < max_size) {
1158 					uint8_t *p;
1159 					p = reallocarray(base_buf, 1, max_size);
1160 					if (p == NULL) {
1161 						err = got_error_from_errno(
1162 						    "reallocarray");
1163 						goto done;
1164 					}
1165 					base_buf = p;
1166 					base_bufsz = max_size;
1167 				}
1168 				accum_buf = base_buf;
1169 				base_buf = tmp;
1170 			} else {
1171 				FILE *tmp = accum_file;
1172 				accum_file = base_file;
1173 				base_file = tmp;
1174 				rewind(base_file);
1175 				rewind(accum_file);
1176 			}
1177 		}
1178 	}
1179 
1180 done:
1181 	free(base_buf);
1182 	if (accum_buf) {
1183 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1184 		free(accum_buf);
1185 		if (len != accum_size)
1186 			err = got_ferror(outfile, GOT_ERR_IO);
1187 	}
1188 	rewind(outfile);
1189 	if (err == NULL)
1190 		*result_size = accum_size;
1191 	return err;
1192 }
1193 
1194 const struct got_error *
1195 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1196     struct got_delta_chain *deltas, struct got_pack *pack)
1197 {
1198 	const struct got_error *err = NULL;
1199 	struct got_delta *delta;
1200 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1201 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1202 	uint64_t max_size;
1203 	int n = 0;
1204 
1205 	*outbuf = NULL;
1206 	*outlen = 0;
1207 
1208 	if (SIMPLEQ_EMPTY(&deltas->entries))
1209 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1210 
1211 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1212 	if (err)
1213 		return err;
1214 	accum_buf = malloc(max_size);
1215 	if (accum_buf == NULL)
1216 		return got_error_from_errno("malloc");
1217 
1218 	/* Deltas are ordered in ascending order. */
1219 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1220 		int cached = 1;
1221 		if (n == 0) {
1222 			size_t delta_data_offset;
1223 
1224 			/* Plain object types are the delta base. */
1225 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1226 			    delta->type != GOT_OBJ_TYPE_TREE &&
1227 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1228 			    delta->type != GOT_OBJ_TYPE_TAG) {
1229 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1230 				goto done;
1231 			}
1232 
1233 			delta_data_offset = delta->offset + delta->tslen;
1234 			if (delta_data_offset >= pack->filesize) {
1235 				err = got_error(GOT_ERR_PACK_OFFSET);
1236 				goto done;
1237 			}
1238 			if (pack->map) {
1239 				size_t mapoff = (size_t)delta_data_offset;
1240 				err = got_inflate_to_mem_mmap(&base_buf,
1241 				    &base_bufsz, NULL, NULL, pack->map,
1242 				    mapoff, pack->filesize - mapoff);
1243 			} else {
1244 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1245 				    == -1) {
1246 					err = got_error_from_errno("lseek");
1247 					goto done;
1248 				}
1249 				err = got_inflate_to_mem_fd(&base_buf,
1250 				    &base_bufsz, NULL, NULL, max_size,
1251 				    pack->fd);
1252 			}
1253 			if (err)
1254 				goto done;
1255 			n++;
1256 			continue;
1257 		}
1258 
1259 		got_delta_cache_get(&delta_buf, &delta_len,
1260 		    pack->delta_cache, delta->data_offset);
1261 		if (delta_buf == NULL) {
1262 			cached = 0;
1263 			err = read_delta_data(&delta_buf, &delta_len,
1264 			    delta->data_offset, pack);
1265 			if (err)
1266 				goto done;
1267 			err = got_delta_cache_add(pack->delta_cache,
1268 			    delta->data_offset, delta_buf, delta_len);
1269 			if (err == NULL)
1270 				cached = 1;
1271 			else if (err->code != GOT_ERR_NO_SPACE) {
1272 				free(delta_buf);
1273 				goto done;
1274 			}
1275 		}
1276 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1277 		    delta_buf, delta_len, accum_buf,
1278 		    &accum_size, max_size);
1279 		if (!cached)
1280 			free(delta_buf);
1281 		n++;
1282 		if (err)
1283 			goto done;
1284 
1285 		if (n < deltas->nentries) {
1286 			/* Accumulated delta becomes the new base. */
1287 			uint8_t *tmp = accum_buf;
1288 			/*
1289 			 * Base buffer switches roles with accumulation buffer.
1290 			 * Ensure it can hold the largest result in the delta
1291 			 * chain. Initial allocation might have been smaller.
1292 			 */
1293 			if (base_bufsz < max_size) {
1294 				uint8_t *p;
1295 				p = reallocarray(base_buf, 1, max_size);
1296 				if (p == NULL) {
1297 					err = got_error_from_errno(
1298 					    "reallocarray");
1299 					goto done;
1300 				}
1301 				base_buf = p;
1302 				base_bufsz = max_size;
1303 			}
1304 			accum_buf = base_buf;
1305 			base_buf = tmp;
1306 		}
1307 	}
1308 
1309 done:
1310 	free(base_buf);
1311 	if (err) {
1312 		free(accum_buf);
1313 		*outbuf = NULL;
1314 		*outlen = 0;
1315 	} else {
1316 		*outbuf = accum_buf;
1317 		*outlen = accum_size;
1318 	}
1319 	return err;
1320 }
1321 
1322 const struct got_error *
1323 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1324     FILE *outfile, FILE *base_file, FILE *accum_file)
1325 {
1326 	const struct got_error *err = NULL;
1327 
1328 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1329 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1330 
1331 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1332 		if (obj->pack_offset >= pack->filesize)
1333 			return got_error(GOT_ERR_PACK_OFFSET);
1334 
1335 		if (pack->map) {
1336 			size_t mapoff = (size_t)obj->pack_offset;
1337 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1338 			    pack->map, mapoff, pack->filesize - mapoff,
1339 			    outfile);
1340 		} else {
1341 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1342 				return got_error_from_errno("lseek");
1343 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1344 			    pack->fd, outfile);
1345 		}
1346 	} else
1347 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1348 		    &obj->deltas, pack, outfile, base_file, accum_file);
1349 
1350 	return err;
1351 }
1352 
1353 const struct got_error *
1354 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1355     struct got_object *obj, struct got_pack *pack)
1356 {
1357 	const struct got_error *err = NULL;
1358 
1359 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1360 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1361 
1362 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1363 		if (obj->pack_offset >= pack->filesize)
1364 			return got_error(GOT_ERR_PACK_OFFSET);
1365 		if (pack->map) {
1366 			size_t mapoff = (size_t)obj->pack_offset;
1367 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1368 			    pack->map, mapoff, pack->filesize - mapoff);
1369 		} else {
1370 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1371 				return got_error_from_errno("lseek");
1372 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1373 			    obj->size, pack->fd);
1374 		}
1375 	} else
1376 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1377 		    pack);
1378 
1379 	return err;
1380 }