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Date:: Sun Nov 10 15:51:05 2019 UTC
Message:: cache delta data buffers in an LRU cache
Actions:: History | Blame | Raw File
1 /*
2  * Copyright (c) 2018, 2019 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 <zlib.h>
33 #include <imsg.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_opentemp.h"
38 #include "got_path.h"
39 
40 #include "got_lib_sha1.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_parse.h"
46 #include "got_lib_privsep.h"
47 #include "got_lib_pack.h"
48 
49 #ifndef nitems
50 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
51 #endif
52 
53 #ifndef MIN
54 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
55 #endif
56 
57 static const struct got_error *
58 verify_fanout_table(uint32_t *fanout_table)
59 {
60 	int i;
61 
62 	for (i = 0; i < 0xff - 1; i++) {
63 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
64 			return got_error(GOT_ERR_BAD_PACKIDX);
65 	}
66 
67 	return NULL;
68 }
69 
70 const struct got_error *
71 got_packidx_init_hdr(struct got_packidx *p, int verify)
72 {
73 	const struct got_error *err = NULL;
74 	struct got_packidx_v2_hdr *h;
75 	SHA1_CTX ctx;
76 	uint8_t sha1[SHA1_DIGEST_LENGTH];
77 	size_t nobj, len_fanout, len_ids, offset, remain;
78 	ssize_t n;
79 	int i;
80 
81 	SHA1Init(&ctx);
82 
83 	h = &p->hdr;
84 	offset = 0;
85 	remain = p->len;
86 
87 	if (remain < sizeof(*h->magic)) {
88 		err = got_error(GOT_ERR_BAD_PACKIDX);
89 		goto done;
90 	}
91 	if (p->map)
92 		h->magic = (uint32_t *)(p->map + offset);
93 	else {
94 		h->magic = malloc(sizeof(*h->magic));
95 		if (h->magic == NULL) {
96 			err = got_error_from_errno("malloc");
97 			goto done;
98 		}
99 		n = read(p->fd, h->magic, sizeof(*h->magic));
100 		if (n < 0) {
101 			err = got_error_from_errno("read");
102 			goto done;
103 		} else if (n != sizeof(*h->magic)) {
104 			err = got_error(GOT_ERR_BAD_PACKIDX);
105 			goto done;
106 		}
107 	}
108 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
109 		err = got_error(GOT_ERR_BAD_PACKIDX);
110 		goto done;
111 	}
112 	offset += sizeof(*h->magic);
113 	remain -= sizeof(*h->magic);
114 
115 	if (verify)
116 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
117 
118 	if (remain < sizeof(*h->version)) {
119 		err = got_error(GOT_ERR_BAD_PACKIDX);
120 		goto done;
121 	}
122 	if (p->map)
123 		h->version = (uint32_t *)(p->map + offset);
124 	else {
125 		h->version = malloc(sizeof(*h->version));
126 		if (h->version == NULL) {
127 			err = got_error_from_errno("malloc");
128 			goto done;
129 		}
130 		n = read(p->fd, h->version, sizeof(*h->version));
131 		if (n < 0) {
132 			err = got_error_from_errno("read");
133 			goto done;
134 		} else if (n != sizeof(*h->version)) {
135 			err = got_error(GOT_ERR_BAD_PACKIDX);
136 			goto done;
137 		}
138 	}
139 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
140 		err = got_error(GOT_ERR_BAD_PACKIDX);
141 		goto done;
142 	}
143 	offset += sizeof(*h->version);
144 	remain -= sizeof(*h->version);
145 
146 	if (verify)
147 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
148 
149 	len_fanout =
150 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
151 	if (remain < len_fanout) {
152 		err = got_error(GOT_ERR_BAD_PACKIDX);
153 		goto done;
154 	}
155 	if (p->map)
156 		h->fanout_table = (uint32_t *)(p->map + offset);
157 	else {
158 		h->fanout_table = malloc(len_fanout);
159 		if (h->fanout_table == NULL) {
160 			err = got_error_from_errno("malloc");
161 			goto done;
162 		}
163 		n = read(p->fd, h->fanout_table, len_fanout);
164 		if (n < 0) {
165 			err = got_error_from_errno("read");
166 			goto done;
167 		} else if (n != len_fanout) {
168 			err = got_error(GOT_ERR_BAD_PACKIDX);
169 			goto done;
170 		}
171 	}
172 	err = verify_fanout_table(h->fanout_table);
173 	if (err)
174 		goto done;
175 	if (verify)
176 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
177 	offset += len_fanout;
178 	remain -= len_fanout;
179 
180 	nobj = betoh32(h->fanout_table[0xff]);
181 	len_ids = nobj * sizeof(*h->sorted_ids);
182 	if (len_ids <= nobj || len_ids > remain) {
183 		err = got_error(GOT_ERR_BAD_PACKIDX);
184 		goto done;
185 	}
186 	if (p->map)
187 		h->sorted_ids =
188 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
189 	else {
190 		h->sorted_ids = malloc(len_ids);
191 		if (h->sorted_ids == NULL) {
192 			err = got_error(GOT_ERR_BAD_PACKIDX);
193 			goto done;
194 		}
195 		n = read(p->fd, h->sorted_ids, len_ids);
196 		if (n < 0)
197 			err = got_error_from_errno("read");
198 		else if (n != len_ids) {
199 			err = got_error(GOT_ERR_BAD_PACKIDX);
200 			goto done;
201 		}
202 	}
203 	if (verify)
204 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
205 	offset += len_ids;
206 	remain -= len_ids;
207 
208 	if (remain < nobj * sizeof(*h->crc32)) {
209 		err = got_error(GOT_ERR_BAD_PACKIDX);
210 		goto done;
211 	}
212 	if (p->map)
213 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
214 	else {
215 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
216 		if (h->crc32 == NULL) {
217 			err = got_error_from_errno("malloc");
218 			goto done;
219 		}
220 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
221 		if (n < 0)
222 			err = got_error_from_errno("read");
223 		else if (n != nobj * sizeof(*h->crc32)) {
224 			err = got_error(GOT_ERR_BAD_PACKIDX);
225 			goto done;
226 		}
227 	}
228 	if (verify)
229 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
230 	remain -= nobj * sizeof(*h->crc32);
231 	offset += nobj * sizeof(*h->crc32);
232 
233 	if (remain < nobj * sizeof(*h->offsets)) {
234 		err = got_error(GOT_ERR_BAD_PACKIDX);
235 		goto done;
236 	}
237 	if (p->map)
238 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
239 	else {
240 		h->offsets = malloc(nobj * sizeof(*h->offsets));
241 		if (h->offsets == NULL) {
242 			err = got_error_from_errno("malloc");
243 			goto done;
244 		}
245 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
246 		if (n < 0)
247 			err = got_error_from_errno("read");
248 		else if (n != nobj * sizeof(*h->offsets)) {
249 			err = got_error(GOT_ERR_BAD_PACKIDX);
250 			goto done;
251 		}
252 	}
253 	if (verify)
254 		SHA1Update(&ctx, (uint8_t *)h->offsets,
255 		    nobj * sizeof(*h->offsets));
256 	remain -= nobj * sizeof(*h->offsets);
257 	offset += nobj * sizeof(*h->offsets);
258 
259 	/* Large file offsets are contained only in files > 2GB. */
260 	for (i = 0; i < nobj; i++) {
261 		uint32_t o = betoh32(h->offsets[i]);
262 		if (o & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX)
263 			p->nlargeobj++;
264 	}
265 	if (p->nlargeobj == 0)
266 		goto checksum;
267 
268 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
269 		err = got_error(GOT_ERR_BAD_PACKIDX);
270 		goto done;
271 	}
272 	if (p->map)
273 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
274 	else {
275 		h->large_offsets = malloc(p->nlargeobj *
276 		    sizeof(*h->large_offsets));
277 		if (h->large_offsets == NULL) {
278 			err = got_error_from_errno("malloc");
279 			goto done;
280 		}
281 		n = read(p->fd, h->large_offsets,
282 		    p->nlargeobj * sizeof(*h->large_offsets));
283 		if (n < 0)
284 			err = got_error_from_errno("read");
285 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
286 			err = got_error(GOT_ERR_BAD_PACKIDX);
287 			goto done;
288 		}
289 	}
290 	if (verify)
291 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
292 		    p->nlargeobj * sizeof(*h->large_offsets));
293 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
294 	offset += p->nlargeobj * sizeof(*h->large_offsets);
295 
296 checksum:
297 	if (remain < sizeof(*h->trailer)) {
298 		err = got_error(GOT_ERR_BAD_PACKIDX);
299 		goto done;
300 	}
301 	if (p->map)
302 		h->trailer =
303 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
304 	else {
305 		h->trailer = malloc(sizeof(*h->trailer));
306 		if (h->trailer == NULL) {
307 			err = got_error_from_errno("malloc");
308 			goto done;
309 		}
310 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
311 		if (n < 0)
312 			err = got_error_from_errno("read");
313 		else if (n != sizeof(*h->trailer)) {
314 			err = got_error(GOT_ERR_BAD_PACKIDX);
315 			goto done;
316 		}
317 	}
318 	if (verify) {
319 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
320 		SHA1Final(sha1, &ctx);
321 		if (memcmp(h->trailer->packidx_sha1, sha1,
322 		    SHA1_DIGEST_LENGTH) != 0)
323 			err = got_error(GOT_ERR_PACKIDX_CSUM);
324 	}
325 done:
326 	return err;
327 }
328 
329 const struct got_error *
330 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
331 {
332 	const struct got_error *err = NULL;
333 	struct got_packidx *p;
334 	struct stat sb;
335 
336 	*packidx = NULL;
337 
338 	p = calloc(1, sizeof(*p));
339 	if (p == NULL)
340 		return got_error_from_errno("calloc");
341 
342 	p->fd = open(path, O_RDONLY | O_NOFOLLOW);
343 	if (p->fd == -1) {
344 		err = got_error_from_errno2("open", path);
345 		free(p);
346 		return err;
347 	}
348 
349 	if (fstat(p->fd, &sb) != 0) {
350 		err = got_error_from_errno2("fstat", path);
351 		close(p->fd);
352 		free(p);
353 		return err;
354 	}
355 	p->len = sb.st_size;
356 	if (p->len < sizeof(p->hdr)) {
357 		err = got_error(GOT_ERR_BAD_PACKIDX);
358 		close(p->fd);
359 		free(p);
360 		return err;
361 	}
362 
363 	p->path_packidx = strdup(path);
364 	if (p->path_packidx == NULL) {
365 		err = got_error_from_errno("strdup");
366 		goto done;
367 	}
368 
369 #ifndef GOT_PACK_NO_MMAP
370 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
371 	if (p->map == MAP_FAILED) {
372 		if (errno != ENOMEM) {
373 			err = got_error_from_errno("mmap");
374 			goto done;
375 		}
376 		p->map = NULL; /* fall back to read(2) */
377 	}
378 #endif
379 
380 	err = got_packidx_init_hdr(p, verify);
381 done:
382 	if (err)
383 		got_packidx_close(p);
384 	else
385 		*packidx = p;
386 
387 	return err;
388 }
389 
390 const struct got_error *
391 got_packidx_close(struct got_packidx *packidx)
392 {
393 	const struct got_error *err = NULL;
394 
395 	free(packidx->path_packidx);
396 	if (packidx->map) {
397 		if (munmap(packidx->map, packidx->len) == -1)
398 			err = got_error_from_errno("munmap");
399 	} else {
400 		free(packidx->hdr.magic);
401 		free(packidx->hdr.version);
402 		free(packidx->hdr.fanout_table);
403 		free(packidx->hdr.sorted_ids);
404 		free(packidx->hdr.crc32);
405 		free(packidx->hdr.offsets);
406 		free(packidx->hdr.large_offsets);
407 		free(packidx->hdr.trailer);
408 	}
409 	if (close(packidx->fd) != 0 && err == NULL)
410 		err = got_error_from_errno("close");
411 	free(packidx);
412 
413 	return err;
414 }
415 
416 static off_t
417 get_object_offset(struct got_packidx *packidx, int idx)
418 {
419 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
420 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
421 		uint64_t loffset;
422 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
423 		if (idx < 0 || idx >= packidx->nlargeobj ||
424 		    packidx->hdr.large_offsets == NULL)
425 			return -1;
426 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
427 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
428 	}
429 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
430 }
431 
432 int
433 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
434 {
435 	u_int8_t id0 = id->sha1[0];
436 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
437 	int left = 0, right = totobj - 1;
438 
439 	if (id0 > 0)
440 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
441 
442 	while (left <= right) {
443 		struct got_packidx_object_id *oid;
444 		int i, cmp;
445 
446 		i = ((left + right) / 2);
447 		oid = &packidx->hdr.sorted_ids[i];
448 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
449 		if (cmp == 0)
450 			return i;
451 		else if (cmp > 0)
452 			left = i + 1;
453 		else if (cmp < 0)
454 			right = i - 1;
455 	}
456 
457 	return -1;
458 }
459 
460 const struct got_error *
461 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
462     struct got_packidx *packidx, const char *id_str_prefix)
463 {
464 	const struct got_error *err = NULL;
465 	u_int8_t id0;
466 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
467 	char hex[3];
468 	size_t prefix_len = strlen(id_str_prefix);
469 	struct got_packidx_object_id *oid;
470 	int i;
471 
472 	SIMPLEQ_INIT(matched_ids);
473 
474 	if (prefix_len < 2)
475 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
476 
477 	hex[0] = id_str_prefix[0];
478 	hex[1] = id_str_prefix[1];
479 	hex[2] = '\0';
480 	if (!got_parse_xdigit(&id0, hex))
481 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
482 
483 	i = betoh32(packidx->hdr.fanout_table[id0 - 1]);
484 	if (i == 0)
485 		return NULL;
486 
487 	oid = &packidx->hdr.sorted_ids[i];
488 	while (i < totobj && oid->sha1[0] == id0) {
489 		char id_str[SHA1_DIGEST_STRING_LENGTH];
490 		struct got_object_qid *qid;
491 		int cmp;
492 
493 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
494 		        return got_error(GOT_ERR_NO_SPACE);
495 
496 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
497 		if (cmp < 0) {
498 			oid = &packidx->hdr.sorted_ids[++i];
499 			continue;
500 		} else if (cmp > 0)
501 			break;
502 
503 		err = got_object_qid_alloc_partial(&qid);
504 		if (err)
505 			break;
506 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
507 		SIMPLEQ_INSERT_TAIL(matched_ids, qid, entry);
508 
509 		oid = &packidx->hdr.sorted_ids[++i];
510 	}
511 
512 	if (err)
513 		got_object_id_queue_free(matched_ids);
514 	return err;
515 }
516 
517 const struct got_error *
518 got_pack_stop_privsep_child(struct got_pack *pack)
519 {
520 	const struct got_error *err = NULL;
521 
522 	if (pack->privsep_child == NULL)
523 		return NULL;
524 
525 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
526 	if (err)
527 		return err;
528 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
529 	if (close(pack->privsep_child->imsg_fd) != 0 && err == NULL)
530 		err = got_error_from_errno("close");
531 	free(pack->privsep_child);
532 	pack->privsep_child = NULL;
533 	return err;
534 }
535 
536 const struct got_error *
537 got_pack_close(struct got_pack *pack)
538 {
539 	const struct got_error *err = NULL;
540 
541 	err = got_pack_stop_privsep_child(pack);
542 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
543 		err = got_error_from_errno("munmap");
544 	if (pack->fd != -1 && close(pack->fd) != 0 && err == NULL)
545 		err = got_error_from_errno("close");
546 	pack->fd = -1;
547 	free(pack->path_packfile);
548 	pack->path_packfile = NULL;
549 	pack->filesize = 0;
550 	if (pack->delta_cache) {
551 		got_delta_cache_free(pack->delta_cache);
552 		pack->delta_cache = NULL;
553 	}
554 
555 	return err;
556 }
557 
558 static const struct got_error *
559 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
560     struct got_pack *pack, off_t offset)
561 {
562 	uint8_t t = 0;
563 	uint64_t s = 0;
564 	uint8_t sizeN;
565 	size_t mapoff = 0;
566 	int i = 0;
567 
568 	*len = 0;
569 
570 	if (offset >= pack->filesize)
571 		return got_error(GOT_ERR_PACK_OFFSET);
572 
573 	if (pack->map) {
574 		mapoff = (size_t)offset;
575 	} else {
576 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
577 			return got_error_from_errno("lseek");
578 	}
579 
580 	do {
581 		/* We do not support size values which don't fit in 64 bit. */
582 		if (i > 9)
583 			return got_error(GOT_ERR_NO_SPACE);
584 
585 		if (pack->map) {
586 			sizeN = *(pack->map + mapoff);
587 			mapoff += sizeof(sizeN);
588 		} else {
589 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
590 			if (n < 0)
591 				return got_error_from_errno("read");
592 			if (n != sizeof(sizeN))
593 				return got_error(GOT_ERR_BAD_PACKFILE);
594 		}
595 		*len += sizeof(sizeN);
596 
597 		if (i == 0) {
598 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
599 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
600 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
601 		} else {
602 			size_t shift = 4 + 7 * (i - 1);
603 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
604 		}
605 		i++;
606 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
607 
608 	*type = t;
609 	*size = s;
610 	return NULL;
611 }
612 
613 static const struct got_error *
614 open_plain_object(struct got_object **obj, const char *path_packfile,
615     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
616 {
617 	*obj = calloc(1, sizeof(**obj));
618 	if (*obj == NULL)
619 		return got_error_from_errno("calloc");
620 
621 	(*obj)->path_packfile = strdup(path_packfile);
622 	if ((*obj)->path_packfile == NULL) {
623 		const struct got_error *err = got_error_from_errno("strdup");
624 		free(*obj);
625 		*obj = NULL;
626 		return err;
627 	}
628 
629 	(*obj)->type = type;
630 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
631 	(*obj)->pack_idx = idx;
632 	(*obj)->hdrlen = 0;
633 	(*obj)->size = size;
634 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
635 	(*obj)->pack_offset = offset;
636 
637 	return NULL;
638 }
639 
640 static const struct got_error *
641 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
642     off_t delta_offset)
643 {
644 	int64_t o = 0;
645 	uint8_t offN;
646 	int i = 0;
647 
648 	*offset = 0;
649 	*len = 0;
650 
651 	do {
652 		/* We do not support offset values which don't fit in 64 bit. */
653 		if (i > 8)
654 			return got_error(GOT_ERR_NO_SPACE);
655 
656 		if (pack->map) {
657 			size_t mapoff;
658 			if (delta_offset >= pack->filesize)
659 				return got_error(GOT_ERR_PACK_OFFSET);
660 			mapoff = (size_t)delta_offset + *len;
661 			offN = *(pack->map + mapoff);
662 		} else {
663 			ssize_t n;
664 			n = read(pack->fd, &offN, sizeof(offN));
665 			if (n < 0)
666 				return got_error_from_errno("read");
667 			if (n != sizeof(offN))
668 				return got_error(GOT_ERR_BAD_PACKFILE);
669 		}
670 		*len += sizeof(offN);
671 
672 		if (i == 0)
673 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
674 		else {
675 			o++;
676 			o <<= 7;
677 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
678 		}
679 		i++;
680 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
681 
682 	*offset = o;
683 	return NULL;
684 }
685 
686 static const struct got_error *
687 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
688     off_t offset, int tslen)
689 {
690 	const struct got_error *err;
691 	int64_t negoffset;
692 	size_t negofflen;
693 
694 	*len = 0;
695 
696 	err = parse_negative_offset(&negoffset, &negofflen, pack,
697 	    offset + tslen);
698 	if (err)
699 		return err;
700 
701 	/* Compute the base object's offset (must be in the same pack file). */
702 	*base_offset = (offset - negoffset);
703 	if (*base_offset <= 0)
704 		return got_error(GOT_ERR_BAD_PACKFILE);
705 
706 	*len = negofflen;
707 	return NULL;
708 }
709 
710 static const struct got_error *
711 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
712     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
713 
714 static const struct got_error *
715 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
716     size_t delta_data_offset, struct got_pack *pack)
717 {
718 	const struct got_error *err = NULL;
719 
720 	if (pack->map) {
721 		if (delta_data_offset >= pack->filesize)
722 			return got_error(GOT_ERR_PACK_OFFSET);
723 		err = got_inflate_to_mem_mmap(delta_buf, delta_len, pack->map,
724 		    delta_data_offset, pack->filesize - delta_data_offset);
725 	} else {
726 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
727 			return got_error_from_errno("lseek");
728 		err = got_inflate_to_mem_fd(delta_buf, delta_len, pack->fd);
729 	}
730 	return err;
731 }
732 
733 static const struct got_error *
734 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
735     int delta_type, size_t delta_size, size_t delta_data_offset)
736 {
737 	struct got_delta *delta;
738 
739 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
740 	    delta_data_offset);
741 	if (delta == NULL)
742 		return got_error_from_errno("got_delta_open");
743 	/* delta is freed in got_object_close() */
744 	deltas->nentries++;
745 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
746 	return NULL;
747 }
748 
749 static const struct got_error *
750 resolve_offset_delta(struct got_delta_chain *deltas,
751     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
752     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
753 
754 {
755 	const struct got_error *err;
756 	off_t base_offset;
757 	uint8_t base_type;
758 	uint64_t base_size;
759 	size_t base_tslen;
760 	off_t delta_data_offset;
761 	size_t consumed;
762 
763 	err = parse_offset_delta(&base_offset, &consumed, pack,
764 	    delta_offset, tslen);
765 	if (err)
766 		return err;
767 
768 	delta_data_offset = delta_offset + tslen + consumed;
769 	if (delta_data_offset >= pack->filesize)
770 		return got_error(GOT_ERR_PACK_OFFSET);
771 
772 	if (pack->map == NULL) {
773 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
774 		if (delta_data_offset == -1)
775 			return got_error_from_errno("lseek");
776 	}
777 
778 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
779 	    delta_data_offset);
780 	if (err)
781 		return err;
782 
783 	/* An offset delta must be in the same packfile. */
784 	if (base_offset >= pack->filesize)
785 		return got_error(GOT_ERR_PACK_OFFSET);
786 
787 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
788 	    pack, base_offset);
789 	if (err)
790 		return err;
791 
792 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
793 	    base_tslen, base_type, base_size, recursion - 1);
794 }
795 
796 static const struct got_error *
797 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
798     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
799     size_t delta_size, unsigned int recursion)
800 {
801 	const struct got_error *err;
802 	struct got_object_id id;
803 	int idx;
804 	off_t base_offset;
805 	uint8_t base_type;
806 	uint64_t base_size;
807 	size_t base_tslen;
808 	off_t delta_data_offset;
809 	uint8_t *delta_buf;
810 	size_t delta_len;
811 
812 	if (delta_offset + tslen >= pack->filesize)
813 		return got_error(GOT_ERR_PACK_OFFSET);
814 
815 	if (pack->map == NULL) {
816 	}
817 
818 	if (pack->map) {
819 		size_t mapoff = delta_offset + tslen;
820 		memcpy(&id, pack->map + mapoff, sizeof(id));
821 		mapoff += sizeof(id);
822 		delta_data_offset = (off_t)mapoff;
823 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
824 		    mapoff, pack->filesize - mapoff);
825 		if (err)
826 			return err;
827 	} else {
828 		ssize_t n;
829 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
830 		if (delta_data_offset == -1)
831 			return got_error_from_errno("lseek");
832 		n = read(pack->fd, &id, sizeof(id));
833 		if (n < 0)
834 			return got_error_from_errno("read");
835 		if (n != sizeof(id))
836 			return got_error(GOT_ERR_BAD_PACKFILE);
837 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
838 		if (err)
839 			return err;
840 	}
841 
842 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
843 	    delta_data_offset);
844 	if (err)
845 		return err;
846 
847 	/* Delta base must be in the same pack file. */
848 	idx = got_packidx_get_object_idx(packidx, &id);
849 	if (idx == -1)
850 		return got_error(GOT_ERR_BAD_PACKFILE);
851 
852 	base_offset = get_object_offset(packidx, idx);
853 	if (base_offset == (uint64_t)-1)
854 		return got_error(GOT_ERR_BAD_PACKIDX);
855 
856 	if (base_offset >= pack->filesize)
857 		return got_error(GOT_ERR_PACK_OFFSET);
858 
859 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
860 	    pack, base_offset);
861 	if (err)
862 		return err;
863 
864 	return resolve_delta_chain(deltas, packidx, pack, base_offset,
865 	    base_tslen, base_type, base_size, recursion - 1);
866 }
867 
868 static const struct got_error *
869 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
870     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
871     size_t delta_size, unsigned int recursion)
872 {
873 	const struct got_error *err = NULL;
874 
875 	if (--recursion == 0)
876 		return got_error(GOT_ERR_RECURSION);
877 
878 	switch (delta_type) {
879 	case GOT_OBJ_TYPE_COMMIT:
880 	case GOT_OBJ_TYPE_TREE:
881 	case GOT_OBJ_TYPE_BLOB:
882 	case GOT_OBJ_TYPE_TAG:
883 		/* Plain types are the final delta base. Recursion ends. */
884 		err = add_delta(deltas, delta_offset, tslen, delta_type,
885 		    delta_size, 0);
886 		break;
887 	case GOT_OBJ_TYPE_OFFSET_DELTA:
888 		err = resolve_offset_delta(deltas, packidx, pack,
889 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
890 		break;
891 	case GOT_OBJ_TYPE_REF_DELTA:
892 		err = resolve_ref_delta(deltas, packidx, pack,
893 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
894 		break;
895 	default:
896 		return got_error(GOT_ERR_OBJ_TYPE);
897 	}
898 
899 	return err;
900 }
901 
902 static const struct got_error *
903 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
904     struct got_pack *pack, struct got_object_id *id, off_t offset,
905     size_t tslen, int delta_type, size_t delta_size, int idx)
906 {
907 	const struct got_error *err = NULL;
908 	int resolved_type;
909 
910 	*obj = calloc(1, sizeof(**obj));
911 	if (*obj == NULL)
912 		return got_error_from_errno("calloc");
913 
914 	(*obj)->flags = 0;
915 	(*obj)->hdrlen = 0;
916 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
917 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
918 	(*obj)->pack_offset = offset + tslen;
919 
920 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
921 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
922 
923 	(*obj)->path_packfile = strdup(pack->path_packfile);
924 	if ((*obj)->path_packfile == NULL) {
925 		err = got_error_from_errno("strdup");
926 		goto done;
927 	}
928 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
929 	(*obj)->pack_idx = idx;
930 
931 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
932 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
933 	if (err)
934 		goto done;
935 
936 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
937 	if (err)
938 		goto done;
939 	(*obj)->type = resolved_type;
940 done:
941 	if (err) {
942 		got_object_close(*obj);
943 		*obj = NULL;
944 	}
945 	return err;
946 }
947 
948 const struct got_error *
949 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
950     struct got_packidx *packidx, int idx, struct got_object_id *id)
951 {
952 	const struct got_error *err = NULL;
953 	off_t offset;
954 	uint8_t type;
955 	uint64_t size;
956 	size_t tslen;
957 
958 	*obj = NULL;
959 
960 	offset = get_object_offset(packidx, idx);
961 	if (offset == (uint64_t)-1)
962 		return got_error(GOT_ERR_BAD_PACKIDX);
963 
964 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
965 	if (err)
966 		return err;
967 
968 	switch (type) {
969 	case GOT_OBJ_TYPE_COMMIT:
970 	case GOT_OBJ_TYPE_TREE:
971 	case GOT_OBJ_TYPE_BLOB:
972 	case GOT_OBJ_TYPE_TAG:
973 		err = open_plain_object(obj, pack->path_packfile, id, type,
974 		    offset + tslen, size, idx);
975 		break;
976 	case GOT_OBJ_TYPE_OFFSET_DELTA:
977 	case GOT_OBJ_TYPE_REF_DELTA:
978 		err = open_delta_object(obj, packidx, pack, id, offset,
979 		    tslen, type, size, idx);
980 		break;
981 	default:
982 		err = got_error(GOT_ERR_OBJ_TYPE);
983 		break;
984 	}
985 
986 	return err;
987 }
988 
989 static const struct got_error *
990 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas,
991     struct got_pack *pack)
992 {
993 	struct got_delta *delta;
994 	uint64_t base_size = 0, result_size = 0;
995 
996 	*max_size = 0;
997 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
998 		/* Plain object types are the delta base. */
999 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1000 		    delta->type != GOT_OBJ_TYPE_TREE &&
1001 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1002 		    delta->type != GOT_OBJ_TYPE_TAG) {
1003 			const struct got_error *err;
1004 			uint8_t *delta_buf;
1005 			size_t delta_len;
1006 			int cached = 1;
1007 
1008 			got_delta_cache_get(&delta_buf, &delta_len,
1009 			    pack->delta_cache, delta->data_offset);
1010 			if (delta_buf == NULL) {
1011 				cached = 0;
1012 				err = read_delta_data(&delta_buf, &delta_len,
1013 				    delta->data_offset, pack);
1014 				if (err)
1015 					return err;
1016 				err = got_delta_cache_add(pack->delta_cache,
1017 				    delta->data_offset, delta_buf, delta_len);
1018 				if (err == NULL)
1019 					cached = 1;
1020 				else if (err->code != GOT_ERR_NO_SPACE) {
1021 					free(delta_buf);
1022 					return err;
1023 				}
1024 			}
1025 			err = got_delta_get_sizes(&base_size, &result_size,
1026 			    delta_buf, delta_len);
1027 			if (!cached)
1028 				free(delta_buf);
1029 			if (err)
1030 				return err;
1031 		} else
1032 			base_size = delta->size;
1033 		if (base_size > *max_size)
1034 			*max_size = base_size;
1035 		if (result_size > *max_size)
1036 			*max_size = result_size;
1037 	}
1038 
1039 	return NULL;
1040 }
1041 
1042 const struct got_error *
1043 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1044     struct got_pack *pack)
1045 {
1046 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1047 		return got_error(GOT_ERR_OBJ_TYPE);
1048 
1049 	return get_delta_chain_max_size(size, &obj->deltas, pack);
1050 }
1051 
1052 static const struct got_error *
1053 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1054     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
1055 {
1056 	const struct got_error *err = NULL;
1057 	struct got_delta *delta;
1058 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1059 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1060 	uint64_t max_size;
1061 	int n = 0;
1062 
1063 	*result_size = 0;
1064 
1065 	if (SIMPLEQ_EMPTY(&deltas->entries))
1066 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1067 
1068 	/* We process small enough files entirely in memory for speed. */
1069 	err = get_delta_chain_max_size(&max_size, deltas, pack);
1070 	if (err)
1071 		return err;
1072 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1073 		accum_buf = malloc(max_size);
1074 		if (accum_buf == NULL)
1075 			return got_error_from_errno("malloc");
1076 		base_file = NULL;
1077 		accum_file = NULL;
1078 	}
1079 
1080 	/* Deltas are ordered in ascending order. */
1081 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1082 		int cached = 1;
1083 		if (n == 0) {
1084 			size_t mapoff;
1085 			off_t delta_data_offset;
1086 
1087 			/* Plain object types are the delta base. */
1088 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1089 			    delta->type != GOT_OBJ_TYPE_TREE &&
1090 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1091 			    delta->type != GOT_OBJ_TYPE_TAG) {
1092 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1093 				goto done;
1094 			}
1095 
1096 			delta_data_offset = delta->offset + delta->tslen;
1097 			if (delta_data_offset >= pack->filesize) {
1098 				err = got_error(GOT_ERR_PACK_OFFSET);
1099 				goto done;
1100 			}
1101 			if (pack->map == NULL) {
1102 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1103 				    == -1) {
1104 					err = got_error_from_errno("lseek");
1105 					goto done;
1106 				}
1107 			}
1108 			if (base_file) {
1109 				if (pack->map) {
1110 					mapoff = (size_t)delta_data_offset;
1111 					err = got_inflate_to_file_mmap(
1112 					    &base_bufsz, pack->map, mapoff,
1113 					    pack->filesize - mapoff, base_file);
1114 				} else
1115 					err = got_inflate_to_file_fd(
1116 					    &base_bufsz, pack->fd, base_file);
1117 			} else {
1118 				if (pack->map) {
1119 					mapoff = (size_t)delta_data_offset;
1120 					err = got_inflate_to_mem_mmap(&base_buf,
1121 					    &base_bufsz, pack->map, mapoff,
1122 					    pack->filesize - mapoff);
1123 				} else
1124 					err = got_inflate_to_mem_fd(&base_buf,
1125 					    &base_bufsz, pack->fd);
1126 			}
1127 			if (err)
1128 				goto done;
1129 			n++;
1130 			if (base_file)
1131 				rewind(base_file);
1132 			continue;
1133 		}
1134 
1135 		got_delta_cache_get(&delta_buf, &delta_len,
1136 		    pack->delta_cache, delta->data_offset);
1137 		if (delta_buf == NULL) {
1138 			cached = 0;
1139 			err = read_delta_data(&delta_buf, &delta_len,
1140 			    delta->data_offset, pack);
1141 			if (err)
1142 				goto done;
1143 			err = got_delta_cache_add(pack->delta_cache,
1144 			    delta->data_offset, delta_buf, delta_len);
1145 			if (err == NULL)
1146 				cached = 1;
1147 			else if (err->code != GOT_ERR_NO_SPACE) {
1148 				free(delta_buf);
1149 				goto done;
1150 			}
1151 		}
1152 		if (base_buf) {
1153 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1154 			    delta_buf, delta_len, accum_buf,
1155 			    &accum_size, max_size);
1156 			n++;
1157 		} else {
1158 			err = got_delta_apply(base_file, delta_buf,
1159 			    delta_len,
1160 			    /* Final delta application writes to output file. */
1161 			    ++n < deltas->nentries ? accum_file : outfile,
1162 			    &accum_size);
1163 		}
1164 		if (!cached)
1165 			free(delta_buf);
1166 		if (err)
1167 			goto done;
1168 
1169 		if (n < deltas->nentries) {
1170 			/* Accumulated delta becomes the new base. */
1171 			if (base_buf) {
1172 				uint8_t *tmp = accum_buf;
1173 				/*
1174 				 * Base buffer switches roles with accumulation
1175 				 * buffer. Ensure it can hold the largest
1176 				 * result in the delta chain. The initial
1177 				 * allocation might have been smaller.
1178 				 */
1179 				if (base_bufsz < max_size) {
1180 					uint8_t *p;
1181 					p = reallocarray(base_buf, 1, max_size);
1182 					if (p == NULL) {
1183 						err = got_error_from_errno(
1184 						    "reallocarray");
1185 						goto done;
1186 					}
1187 					base_buf = p;
1188 					base_bufsz = max_size;
1189 				}
1190 				accum_buf = base_buf;
1191 				base_buf = tmp;
1192 			} else {
1193 				FILE *tmp = accum_file;
1194 				accum_file = base_file;
1195 				base_file = tmp;
1196 				rewind(base_file);
1197 				rewind(accum_file);
1198 			}
1199 		}
1200 	}
1201 
1202 done:
1203 	free(base_buf);
1204 	if (accum_buf) {
1205 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1206 		free(accum_buf);
1207 		if (len != accum_size)
1208 			err = got_ferror(outfile, GOT_ERR_IO);
1209 	}
1210 	rewind(outfile);
1211 	if (err == NULL)
1212 		*result_size = accum_size;
1213 	return err;
1214 }
1215 
1216 static const struct got_error *
1217 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1218     struct got_delta_chain *deltas, struct got_pack *pack)
1219 {
1220 	const struct got_error *err = NULL;
1221 	struct got_delta *delta;
1222 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1223 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1224 	uint64_t max_size;
1225 	int n = 0;
1226 
1227 	*outbuf = NULL;
1228 	*outlen = 0;
1229 
1230 	if (SIMPLEQ_EMPTY(&deltas->entries))
1231 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1232 
1233 	err = get_delta_chain_max_size(&max_size, deltas, pack);
1234 	if (err)
1235 		return err;
1236 	accum_buf = malloc(max_size);
1237 	if (accum_buf == NULL)
1238 		return got_error_from_errno("malloc");
1239 
1240 	/* Deltas are ordered in ascending order. */
1241 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1242 		int cached = 1;
1243 		if (n == 0) {
1244 			size_t delta_data_offset;
1245 
1246 			/* Plain object types are the delta base. */
1247 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1248 			    delta->type != GOT_OBJ_TYPE_TREE &&
1249 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1250 			    delta->type != GOT_OBJ_TYPE_TAG) {
1251 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1252 				goto done;
1253 			}
1254 
1255 			delta_data_offset = delta->offset + delta->tslen;
1256 			if (delta_data_offset >= pack->filesize) {
1257 				err = got_error(GOT_ERR_PACK_OFFSET);
1258 				goto done;
1259 			}
1260 			if (pack->map) {
1261 				size_t mapoff = (size_t)delta_data_offset;
1262 				err = got_inflate_to_mem_mmap(&base_buf,
1263 				    &base_bufsz, pack->map, mapoff,
1264 				    pack->filesize - mapoff);
1265 			} else {
1266 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1267 				    == -1) {
1268 					err = got_error_from_errno("lseek");
1269 					goto done;
1270 				}
1271 				err = got_inflate_to_mem_fd(&base_buf,
1272 				    &base_bufsz, pack->fd);
1273 			}
1274 			if (err)
1275 				goto done;
1276 			n++;
1277 			continue;
1278 		}
1279 
1280 		got_delta_cache_get(&delta_buf, &delta_len,
1281 		    pack->delta_cache, delta->data_offset);
1282 		if (delta_buf == NULL) {
1283 			cached = 0;
1284 			err = read_delta_data(&delta_buf, &delta_len,
1285 			    delta->data_offset, pack);
1286 			if (err)
1287 				goto done;
1288 			err = got_delta_cache_add(pack->delta_cache,
1289 			    delta->data_offset, delta_buf, delta_len);
1290 			if (err == NULL)
1291 				cached = 1;
1292 			else if (err->code != GOT_ERR_NO_SPACE) {
1293 				free(delta_buf);
1294 				goto done;
1295 			}
1296 		}
1297 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1298 		    delta_buf, delta_len, accum_buf,
1299 		    &accum_size, max_size);
1300 		if (!cached)
1301 			free(delta_buf);
1302 		n++;
1303 		if (err)
1304 			goto done;
1305 
1306 		if (n < deltas->nentries) {
1307 			/* Accumulated delta becomes the new base. */
1308 			uint8_t *tmp = accum_buf;
1309 			/*
1310 			 * Base buffer switches roles with accumulation buffer.
1311 			 * Ensure it can hold the largest result in the delta
1312 			 * chain. Initial allocation might have been smaller.
1313 			 */
1314 			if (base_bufsz < max_size) {
1315 				uint8_t *p;
1316 				p = reallocarray(base_buf, 1, max_size);
1317 				if (p == NULL) {
1318 					err = got_error_from_errno(
1319 					    "reallocarray");
1320 					goto done;
1321 				}
1322 				base_buf = p;
1323 				base_bufsz = max_size;
1324 			}
1325 			accum_buf = base_buf;
1326 			base_buf = tmp;
1327 		}
1328 	}
1329 
1330 done:
1331 	free(base_buf);
1332 	if (err) {
1333 		free(accum_buf);
1334 		*outbuf = NULL;
1335 		*outlen = 0;
1336 	} else {
1337 		*outbuf = accum_buf;
1338 		*outlen = accum_size;
1339 	}
1340 	return err;
1341 }
1342 
1343 const struct got_error *
1344 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1345     FILE *outfile, FILE *base_file, FILE *accum_file)
1346 {
1347 	const struct got_error *err = NULL;
1348 
1349 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1350 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1351 
1352 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1353 		if (obj->pack_offset >= pack->filesize)
1354 			return got_error(GOT_ERR_PACK_OFFSET);
1355 
1356 		if (pack->map) {
1357 			size_t mapoff = (size_t)obj->pack_offset;
1358 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1359 			    mapoff, pack->filesize - mapoff, outfile);
1360 		} else {
1361 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1362 				return got_error_from_errno("lseek");
1363 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1364 			    outfile);
1365 		}
1366 	} else
1367 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1368 		    outfile, base_file, accum_file);
1369 
1370 	return err;
1371 }
1372 
1373 const struct got_error *
1374 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1375     struct got_object *obj, struct got_pack *pack)
1376 {
1377 	const struct got_error *err = NULL;
1378 
1379 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1380 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1381 
1382 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1383 		if (obj->pack_offset >= pack->filesize)
1384 			return got_error(GOT_ERR_PACK_OFFSET);
1385 		if (pack->map) {
1386 			size_t mapoff = (size_t)obj->pack_offset;
1387 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1388 			    mapoff, pack->filesize - mapoff);
1389 		} else {
1390 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1391 				return got_error_from_errno("lseek");
1392 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1393 		}
1394 	} else
1395 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1396 
1397 	return err;
1398 }