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 (*h->magic != htobe32(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 (*h->version != htobe32(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 = h->offsets[i];
263 		if (o & htobe32(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 = NULL;
336 	char *pack_relpath;
337 	struct stat sb;
338 
339 	*packidx = NULL;
340 
341 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
342 	if (err)
343 		return err;
344 
345 	/*
346 	 * Ensure that a corresponding pack file exists.
347 	 * Some Git repositories have this problem. Git seems to ignore
348 	 * the existence of lonely pack index files but we do not.
349 	 */
350 	if (fstatat(dir_fd, pack_relpath, &sb, 0) == -1) {
351 		if (errno == ENOENT) {
352 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
353 			    "%s", relpath);
354 		} else
355 			err = got_error_from_errno2("fstatat", pack_relpath);
356 		goto done;
357 	}
358 
359 	p = calloc(1, sizeof(*p));
360 	if (p == NULL) {
361 		err = got_error_from_errno("calloc");
362 		goto done;
363 	}
364 
365 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW);
366 	if (p->fd == -1) {
367 		err = got_error_from_errno2("openat", relpath);
368 		free(p);
369 		goto done;
370 	}
371 
372 	if (fstat(p->fd, &sb) != 0) {
373 		err = got_error_from_errno2("fstat", relpath);
374 		close(p->fd);
375 		free(p);
376 		goto done;
377 	}
378 	p->len = sb.st_size;
379 	if (p->len < sizeof(p->hdr)) {
380 		err = got_error(GOT_ERR_BAD_PACKIDX);
381 		close(p->fd);
382 		free(p);
383 		goto done;
384 	}
385 
386 	p->path_packidx = strdup(relpath);
387 	if (p->path_packidx == NULL) {
388 		err = got_error_from_errno("strdup");
389 		goto done;
390 	}
391 
392 #ifndef GOT_PACK_NO_MMAP
393 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
394 	if (p->map == MAP_FAILED) {
395 		if (errno != ENOMEM) {
396 			err = got_error_from_errno("mmap");
397 			goto done;
398 		}
399 		p->map = NULL; /* fall back to read(2) */
400 	}
401 #endif
402 
403 	err = got_packidx_init_hdr(p, verify);
404 done:
405 	if (err) {
406 		if (p)
407 			got_packidx_close(p);
408 	} else
409 		*packidx = p;
410 	free(pack_relpath);
411 	return err;
412 }
413 
414 const struct got_error *
415 got_packidx_close(struct got_packidx *packidx)
416 {
417 	const struct got_error *err = NULL;
418 
419 	free(packidx->path_packidx);
420 	if (packidx->map) {
421 		if (munmap(packidx->map, packidx->len) == -1)
422 			err = got_error_from_errno("munmap");
423 	} else {
424 		free(packidx->hdr.magic);
425 		free(packidx->hdr.version);
426 		free(packidx->hdr.fanout_table);
427 		free(packidx->hdr.sorted_ids);
428 		free(packidx->hdr.crc32);
429 		free(packidx->hdr.offsets);
430 		free(packidx->hdr.large_offsets);
431 		free(packidx->hdr.trailer);
432 	}
433 	if (close(packidx->fd) == -1 && err == NULL)
434 		err = got_error_from_errno("close");
435 	free(packidx);
436 
437 	return err;
438 }
439 
440 const struct got_error *
441 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
442 {
443 	size_t size;
444 
445 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
446 	size = strlen(path_packidx) + 2;
447 	if (size < GOT_PACKFILE_NAMELEN + 1)
448 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
449 
450 	*path_packfile = malloc(size);
451 	if (*path_packfile == NULL)
452 		return got_error_from_errno("malloc");
453 
454 	/* Copy up to and excluding ".idx". */
455 	if (strlcpy(*path_packfile, path_packidx,
456 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
457 		return got_error(GOT_ERR_NO_SPACE);
458 
459 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
460 		return got_error(GOT_ERR_NO_SPACE);
461 
462 	return NULL;
463 }
464 
465 off_t
466 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
467 {
468 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
469 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
470 		uint64_t loffset;
471 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
472 		if (idx < 0 || idx >= packidx->nlargeobj ||
473 		    packidx->hdr.large_offsets == NULL)
474 			return -1;
475 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
476 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
477 	}
478 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
479 }
480 
481 int
482 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
483 {
484 	u_int8_t id0 = id->sha1[0];
485 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
486 	int left = 0, right = totobj - 1;
487 
488 	if (id0 > 0)
489 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
490 
491 	while (left <= right) {
492 		struct got_packidx_object_id *oid;
493 		int i, cmp;
494 
495 		i = ((left + right) / 2);
496 		oid = &packidx->hdr.sorted_ids[i];
497 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
498 		if (cmp == 0)
499 			return i;
500 		else if (cmp > 0)
501 			left = i + 1;
502 		else if (cmp < 0)
503 			right = i - 1;
504 	}
505 
506 	return -1;
507 }
508 
509 const struct got_error *
510 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
511     struct got_packidx *packidx, const char *id_str_prefix)
512 {
513 	const struct got_error *err = NULL;
514 	u_int8_t id0;
515 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
516 	char hex[3];
517 	size_t prefix_len = strlen(id_str_prefix);
518 	struct got_packidx_object_id *oid;
519 	uint32_t i;
520 
521 	STAILQ_INIT(matched_ids);
522 
523 	if (prefix_len < 2)
524 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
525 
526 	hex[0] = id_str_prefix[0];
527 	hex[1] = id_str_prefix[1];
528 	hex[2] = '\0';
529 	if (!got_parse_xdigit(&id0, hex))
530 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
531 
532 	i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
533 	oid = &packidx->hdr.sorted_ids[i];
534 	while (i < totobj && oid->sha1[0] == id0) {
535 		char id_str[SHA1_DIGEST_STRING_LENGTH];
536 		struct got_object_qid *qid;
537 		int cmp;
538 
539 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
540 		        return got_error(GOT_ERR_NO_SPACE);
541 
542 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
543 		if (cmp < 0) {
544 			oid = &packidx->hdr.sorted_ids[++i];
545 			continue;
546 		} else if (cmp > 0)
547 			break;
548 
549 		err = got_object_qid_alloc_partial(&qid);
550 		if (err)
551 			break;
552 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
553 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
554 
555 		oid = &packidx->hdr.sorted_ids[++i];
556 	}
557 
558 	if (err)
559 		got_object_id_queue_free(matched_ids);
560 	return err;
561 }
562 
563 static const struct got_error *
564 pack_stop_privsep_child(struct got_pack *pack)
565 {
566 	const struct got_error *err = NULL;
567 
568 	if (pack->privsep_child == NULL)
569 		return NULL;
570 
571 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
572 	if (err)
573 		return err;
574 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
575 	if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
576 		err = got_error_from_errno("close");
577 	imsg_clear(pack->privsep_child->ibuf);
578 	free(pack->privsep_child->ibuf);
579 	free(pack->privsep_child);
580 	pack->privsep_child = NULL;
581 	return err;
582 }
583 
584 const struct got_error *
585 got_pack_close(struct got_pack *pack)
586 {
587 	const struct got_error *err = NULL;
588 
589 	err = pack_stop_privsep_child(pack);
590 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
591 		err = got_error_from_errno("munmap");
592 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
593 		err = got_error_from_errno("close");
594 	pack->fd = -1;
595 	free(pack->path_packfile);
596 	pack->path_packfile = NULL;
597 	pack->filesize = 0;
598 	if (pack->delta_cache) {
599 		got_delta_cache_free(pack->delta_cache);
600 		pack->delta_cache = NULL;
601 	}
602 
603 	return err;
604 }
605 
606 const struct got_error *
607 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
608     struct got_pack *pack, off_t offset)
609 {
610 	uint8_t t = 0;
611 	uint64_t s = 0;
612 	uint8_t sizeN;
613 	size_t mapoff = 0;
614 	int i = 0;
615 
616 	*len = 0;
617 
618 	if (offset >= pack->filesize)
619 		return got_error(GOT_ERR_PACK_OFFSET);
620 
621 	if (pack->map) {
622 		mapoff = (size_t)offset;
623 	} else {
624 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
625 			return got_error_from_errno("lseek");
626 	}
627 
628 	do {
629 		/* We do not support size values which don't fit in 64 bit. */
630 		if (i > 9)
631 			return got_error(GOT_ERR_NO_SPACE);
632 
633 		if (pack->map) {
634 			sizeN = *(pack->map + mapoff);
635 			mapoff += sizeof(sizeN);
636 		} else {
637 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
638 			if (n < 0)
639 				return got_error_from_errno("read");
640 			if (n != sizeof(sizeN))
641 				return got_error(GOT_ERR_BAD_PACKFILE);
642 		}
643 		*len += sizeof(sizeN);
644 
645 		if (i == 0) {
646 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
647 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
648 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
649 		} else {
650 			size_t shift = 4 + 7 * (i - 1);
651 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
652 		}
653 		i++;
654 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
655 
656 	*type = t;
657 	*size = s;
658 	return NULL;
659 }
660 
661 static const struct got_error *
662 open_plain_object(struct got_object **obj, struct got_object_id *id,
663     uint8_t type, off_t offset, size_t size, int idx)
664 {
665 	*obj = calloc(1, sizeof(**obj));
666 	if (*obj == NULL)
667 		return got_error_from_errno("calloc");
668 
669 	(*obj)->type = type;
670 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
671 	(*obj)->pack_idx = idx;
672 	(*obj)->hdrlen = 0;
673 	(*obj)->size = size;
674 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
675 	(*obj)->pack_offset = offset;
676 
677 	return NULL;
678 }
679 
680 static const struct got_error *
681 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
682     off_t delta_offset)
683 {
684 	int64_t o = 0;
685 	uint8_t offN;
686 	int i = 0;
687 
688 	*offset = 0;
689 	*len = 0;
690 
691 	do {
692 		/* We do not support offset values which don't fit in 64 bit. */
693 		if (i > 8)
694 			return got_error(GOT_ERR_NO_SPACE);
695 
696 		if (pack->map) {
697 			size_t mapoff;
698 			if (delta_offset >= pack->filesize)
699 				return got_error(GOT_ERR_PACK_OFFSET);
700 			mapoff = (size_t)delta_offset + *len;
701 			offN = *(pack->map + mapoff);
702 		} else {
703 			ssize_t n;
704 			n = read(pack->fd, &offN, sizeof(offN));
705 			if (n < 0)
706 				return got_error_from_errno("read");
707 			if (n != sizeof(offN))
708 				return got_error(GOT_ERR_BAD_PACKFILE);
709 		}
710 		*len += sizeof(offN);
711 
712 		if (i == 0)
713 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
714 		else {
715 			o++;
716 			o <<= 7;
717 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
718 		}
719 		i++;
720 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
721 
722 	*offset = o;
723 	return NULL;
724 }
725 
726 const struct got_error *
727 got_pack_parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
728     off_t offset, int tslen)
729 {
730 	const struct got_error *err;
731 	int64_t negoffset;
732 	size_t negofflen;
733 
734 	*len = 0;
735 
736 	err = parse_negative_offset(&negoffset, &negofflen, pack,
737 	    offset + tslen);
738 	if (err)
739 		return err;
740 
741 	/* Compute the base object's offset (must be in the same pack file). */
742 	*base_offset = (offset - negoffset);
743 	if (*base_offset <= 0)
744 		return got_error(GOT_ERR_BAD_PACKFILE);
745 
746 	*len = negofflen;
747 	return NULL;
748 }
749 
750 static const struct got_error *
751 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
752     size_t delta_data_offset, struct got_pack *pack)
753 {
754 	const struct got_error *err = NULL;
755 
756 	if (pack->map) {
757 		if (delta_data_offset >= pack->filesize)
758 			return got_error(GOT_ERR_PACK_OFFSET);
759 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
760 		    NULL, NULL, pack->map, delta_data_offset,
761 		    pack->filesize - delta_data_offset);
762 	} else {
763 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
764 			return got_error_from_errno("lseek");
765 		err = got_inflate_to_mem_fd(delta_buf, delta_len, NULL,
766 		    NULL, 0, pack->fd);
767 	}
768 	return err;
769 }
770 
771 static const struct got_error *
772 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
773     int delta_type, size_t delta_size, size_t delta_data_offset)
774 {
775 	struct got_delta *delta;
776 
777 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
778 	    delta_data_offset);
779 	if (delta == NULL)
780 		return got_error_from_errno("got_delta_open");
781 	/* delta is freed in got_object_close() */
782 	deltas->nentries++;
783 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
784 	return NULL;
785 }
786 
787 static const struct got_error *
788 resolve_offset_delta(struct got_delta_chain *deltas,
789     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
790     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
791 
792 {
793 	const struct got_error *err;
794 	off_t base_offset;
795 	uint8_t base_type;
796 	uint64_t base_size;
797 	size_t base_tslen;
798 	off_t delta_data_offset;
799 	size_t consumed;
800 
801 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
802 	    delta_offset, tslen);
803 	if (err)
804 		return err;
805 
806 	delta_data_offset = delta_offset + tslen + consumed;
807 	if (delta_data_offset >= pack->filesize)
808 		return got_error(GOT_ERR_PACK_OFFSET);
809 
810 	if (pack->map == NULL) {
811 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
812 		if (delta_data_offset == -1)
813 			return got_error_from_errno("lseek");
814 	}
815 
816 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
817 	    delta_data_offset);
818 	if (err)
819 		return err;
820 
821 	/* An offset delta must be in the same packfile. */
822 	if (base_offset >= pack->filesize)
823 		return got_error(GOT_ERR_PACK_OFFSET);
824 
825 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
826 	    &base_tslen, pack, base_offset);
827 	if (err)
828 		return err;
829 
830 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
831 	    base_tslen, base_type, base_size, recursion - 1);
832 }
833 
834 const struct got_error *
835 got_pack_parse_ref_delta(struct got_object_id *id,
836     struct got_pack *pack, off_t delta_offset, int tslen)
837 {
838 	if (pack->map) {
839 		size_t mapoff = delta_offset + tslen;
840 		memcpy(id, pack->map + mapoff, sizeof(*id));
841 	} else {
842 		ssize_t n;
843 		n = read(pack->fd, id, sizeof(*id));
844 		if (n < 0)
845 			return got_error_from_errno("read");
846 		if (n != sizeof(*id))
847 			return got_error(GOT_ERR_BAD_PACKFILE);
848 	}
849 
850 	return NULL;
851 }
852 
853 static const struct got_error *
854 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
855     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
856     size_t delta_size, unsigned int recursion)
857 {
858 	const struct got_error *err;
859 	struct got_object_id id;
860 	int idx;
861 	off_t base_offset;
862 	uint8_t base_type;
863 	uint64_t base_size;
864 	size_t base_tslen;
865 	off_t delta_data_offset;
866 
867 	if (delta_offset + tslen >= pack->filesize)
868 		return got_error(GOT_ERR_PACK_OFFSET);
869 
870 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
871 	if (err)
872 		return err;
873 	if (pack->map) {
874 		delta_data_offset = delta_offset + tslen + sizeof(id);
875 	} else {
876 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
877 		if (delta_data_offset == -1)
878 			return got_error_from_errno("lseek");
879 	}
880 
881 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
882 	    delta_data_offset);
883 	if (err)
884 		return err;
885 
886 	/* Delta base must be in the same pack file. */
887 	idx = got_packidx_get_object_idx(packidx, &id);
888 	if (idx == -1)
889 		return got_error(GOT_ERR_NO_OBJ);
890 
891 	base_offset = got_packidx_get_object_offset(packidx, idx);
892 	if (base_offset == (uint64_t)-1)
893 		return got_error(GOT_ERR_BAD_PACKIDX);
894 
895 	if (base_offset >= pack->filesize)
896 		return got_error(GOT_ERR_PACK_OFFSET);
897 
898 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
899 	    &base_tslen, pack, base_offset);
900 	if (err)
901 		return err;
902 
903 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
904 	    base_tslen, base_type, base_size, recursion - 1);
905 }
906 
907 const struct got_error *
908 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
909     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
910     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
911 {
912 	const struct got_error *err = NULL;
913 
914 	if (--recursion == 0)
915 		return got_error(GOT_ERR_RECURSION);
916 
917 	switch (delta_type) {
918 	case GOT_OBJ_TYPE_COMMIT:
919 	case GOT_OBJ_TYPE_TREE:
920 	case GOT_OBJ_TYPE_BLOB:
921 	case GOT_OBJ_TYPE_TAG:
922 		/* Plain types are the final delta base. Recursion ends. */
923 		err = add_delta(deltas, delta_offset, tslen, delta_type,
924 		    delta_size, 0);
925 		break;
926 	case GOT_OBJ_TYPE_OFFSET_DELTA:
927 		err = resolve_offset_delta(deltas, packidx, pack,
928 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
929 		break;
930 	case GOT_OBJ_TYPE_REF_DELTA:
931 		err = resolve_ref_delta(deltas, packidx, pack,
932 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
933 		break;
934 	default:
935 		return got_error(GOT_ERR_OBJ_TYPE);
936 	}
937 
938 	return err;
939 }
940 
941 static const struct got_error *
942 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
943     struct got_pack *pack, struct got_object_id *id, off_t offset,
944     size_t tslen, int delta_type, size_t delta_size, int idx)
945 {
946 	const struct got_error *err = NULL;
947 	int resolved_type;
948 
949 	*obj = calloc(1, sizeof(**obj));
950 	if (*obj == NULL)
951 		return got_error_from_errno("calloc");
952 
953 	(*obj)->flags = 0;
954 	(*obj)->hdrlen = 0;
955 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
956 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
957 	(*obj)->pack_offset = offset + tslen;
958 
959 	STAILQ_INIT(&(*obj)->deltas.entries);
960 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
961 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
962 	(*obj)->pack_idx = idx;
963 
964 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
965 	    offset, tslen, delta_type, delta_size,
966 	    GOT_DELTA_CHAIN_RECURSION_MAX);
967 	if (err)
968 		goto done;
969 
970 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
971 	if (err)
972 		goto done;
973 	(*obj)->type = resolved_type;
974 done:
975 	if (err) {
976 		got_object_close(*obj);
977 		*obj = NULL;
978 	}
979 	return err;
980 }
981 
982 const struct got_error *
983 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
984     struct got_packidx *packidx, int idx, struct got_object_id *id)
985 {
986 	const struct got_error *err = NULL;
987 	off_t offset;
988 	uint8_t type;
989 	uint64_t size;
990 	size_t tslen;
991 
992 	*obj = NULL;
993 
994 	offset = got_packidx_get_object_offset(packidx, idx);
995 	if (offset == (uint64_t)-1)
996 		return got_error(GOT_ERR_BAD_PACKIDX);
997 
998 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
999 	    pack, offset);
1000 	if (err)
1001 		return err;
1002 
1003 	switch (type) {
1004 	case GOT_OBJ_TYPE_COMMIT:
1005 	case GOT_OBJ_TYPE_TREE:
1006 	case GOT_OBJ_TYPE_BLOB:
1007 	case GOT_OBJ_TYPE_TAG:
1008 		err = open_plain_object(obj, id, type, offset + tslen,
1009 		    size, idx);
1010 		break;
1011 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1012 	case GOT_OBJ_TYPE_REF_DELTA:
1013 		err = open_delta_object(obj, packidx, pack, id, offset,
1014 		    tslen, type, size, idx);
1015 		break;
1016 	default:
1017 		err = got_error(GOT_ERR_OBJ_TYPE);
1018 		break;
1019 	}
1020 
1021 	return err;
1022 }
1023 
1024 const struct got_error *
1025 got_pack_get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas,
1026     struct got_pack *pack)
1027 {
1028 	struct got_delta *delta;
1029 	uint64_t base_size = 0, result_size = 0;
1030 
1031 	*max_size = 0;
1032 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1033 		/* Plain object types are the delta base. */
1034 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1035 		    delta->type != GOT_OBJ_TYPE_TREE &&
1036 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1037 		    delta->type != GOT_OBJ_TYPE_TAG) {
1038 			const struct got_error *err;
1039 			uint8_t *delta_buf;
1040 			size_t delta_len;
1041 			int cached = 1;
1042 
1043 			got_delta_cache_get(&delta_buf, &delta_len,
1044 			    pack->delta_cache, delta->data_offset);
1045 			if (delta_buf == NULL) {
1046 				cached = 0;
1047 				err = read_delta_data(&delta_buf, &delta_len,
1048 				    delta->data_offset, pack);
1049 				if (err)
1050 					return err;
1051 				err = got_delta_cache_add(pack->delta_cache,
1052 				    delta->data_offset, delta_buf, delta_len);
1053 				if (err == NULL)
1054 					cached = 1;
1055 				else if (err->code != GOT_ERR_NO_SPACE) {
1056 					free(delta_buf);
1057 					return err;
1058 				}
1059 			}
1060 			err = got_delta_get_sizes(&base_size, &result_size,
1061 			    delta_buf, delta_len);
1062 			if (!cached)
1063 				free(delta_buf);
1064 			if (err)
1065 				return err;
1066 		} else
1067 			base_size = delta->size;
1068 		if (base_size > *max_size)
1069 			*max_size = base_size;
1070 		if (result_size > *max_size)
1071 			*max_size = result_size;
1072 	}
1073 
1074 	return NULL;
1075 }
1076 
1077 const struct got_error *
1078 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1079     struct got_pack *pack)
1080 {
1081 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1082 		return got_error(GOT_ERR_OBJ_TYPE);
1083 
1084 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1085 }
1086 
1087 const struct got_error *
1088 got_pack_dump_delta_chain_to_file(size_t *result_size,
1089     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1090     FILE *base_file, FILE *accum_file)
1091 {
1092 	const struct got_error *err = NULL;
1093 	struct got_delta *delta;
1094 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1095 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1096 	uint64_t max_size;
1097 	int n = 0;
1098 
1099 	*result_size = 0;
1100 
1101 	if (STAILQ_EMPTY(&deltas->entries))
1102 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1103 
1104 	/* We process small enough files entirely in memory for speed. */
1105 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1106 	if (err)
1107 		return err;
1108 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1109 		accum_buf = malloc(max_size);
1110 		if (accum_buf == NULL)
1111 			return got_error_from_errno("malloc");
1112 		base_file = NULL;
1113 		accum_file = NULL;
1114 	}
1115 
1116 	/* Deltas are ordered in ascending order. */
1117 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1118 		int cached = 1;
1119 		if (n == 0) {
1120 			size_t mapoff;
1121 			off_t delta_data_offset;
1122 
1123 			/* Plain object types are the delta base. */
1124 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1125 			    delta->type != GOT_OBJ_TYPE_TREE &&
1126 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1127 			    delta->type != GOT_OBJ_TYPE_TAG) {
1128 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1129 				goto done;
1130 			}
1131 
1132 			delta_data_offset = delta->offset + delta->tslen;
1133 			if (delta_data_offset >= pack->filesize) {
1134 				err = got_error(GOT_ERR_PACK_OFFSET);
1135 				goto done;
1136 			}
1137 			if (pack->map == NULL) {
1138 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1139 				    == -1) {
1140 					err = got_error_from_errno("lseek");
1141 					goto done;
1142 				}
1143 			}
1144 			if (base_file) {
1145 				if (pack->map) {
1146 					mapoff = (size_t)delta_data_offset;
1147 					err = got_inflate_to_file_mmap(
1148 					    &base_bufsz, NULL, NULL, pack->map,
1149 					    mapoff, pack->filesize - mapoff,
1150 					    base_file);
1151 				} else
1152 					err = got_inflate_to_file_fd(
1153 					    &base_bufsz, NULL, NULL, pack->fd,
1154 					    base_file);
1155 			} else {
1156 				if (pack->map) {
1157 					mapoff = (size_t)delta_data_offset;
1158 					err = got_inflate_to_mem_mmap(&base_buf,
1159 					    &base_bufsz, NULL, NULL,
1160 					    pack->map, mapoff,
1161 					    pack->filesize - mapoff);
1162 				} else
1163 					err = got_inflate_to_mem_fd(&base_buf,
1164 					    &base_bufsz, NULL, NULL, max_size,
1165 					    pack->fd);
1166 			}
1167 			if (err)
1168 				goto done;
1169 			n++;
1170 			if (base_file)
1171 				rewind(base_file);
1172 			continue;
1173 		}
1174 
1175 		got_delta_cache_get(&delta_buf, &delta_len,
1176 		    pack->delta_cache, delta->data_offset);
1177 		if (delta_buf == NULL) {
1178 			cached = 0;
1179 			err = read_delta_data(&delta_buf, &delta_len,
1180 			    delta->data_offset, pack);
1181 			if (err)
1182 				goto done;
1183 			err = got_delta_cache_add(pack->delta_cache,
1184 			    delta->data_offset, delta_buf, delta_len);
1185 			if (err == NULL)
1186 				cached = 1;
1187 			else if (err->code != GOT_ERR_NO_SPACE) {
1188 				free(delta_buf);
1189 				goto done;
1190 			}
1191 		}
1192 		if (base_buf) {
1193 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1194 			    delta_buf, delta_len, accum_buf,
1195 			    &accum_size, max_size);
1196 			n++;
1197 		} else {
1198 			err = got_delta_apply(base_file, delta_buf,
1199 			    delta_len,
1200 			    /* Final delta application writes to output file. */
1201 			    ++n < deltas->nentries ? accum_file : outfile,
1202 			    &accum_size);
1203 		}
1204 		if (!cached)
1205 			free(delta_buf);
1206 		if (err)
1207 			goto done;
1208 
1209 		if (n < deltas->nentries) {
1210 			/* Accumulated delta becomes the new base. */
1211 			if (base_buf) {
1212 				uint8_t *tmp = accum_buf;
1213 				/*
1214 				 * Base buffer switches roles with accumulation
1215 				 * buffer. Ensure it can hold the largest
1216 				 * result in the delta chain. The initial
1217 				 * allocation might have been smaller.
1218 				 */
1219 				if (base_bufsz < max_size) {
1220 					uint8_t *p;
1221 					p = reallocarray(base_buf, 1, max_size);
1222 					if (p == NULL) {
1223 						err = got_error_from_errno(
1224 						    "reallocarray");
1225 						goto done;
1226 					}
1227 					base_buf = p;
1228 					base_bufsz = max_size;
1229 				}
1230 				accum_buf = base_buf;
1231 				base_buf = tmp;
1232 			} else {
1233 				FILE *tmp = accum_file;
1234 				accum_file = base_file;
1235 				base_file = tmp;
1236 				rewind(base_file);
1237 				rewind(accum_file);
1238 			}
1239 		}
1240 	}
1241 
1242 done:
1243 	free(base_buf);
1244 	if (accum_buf) {
1245 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1246 		free(accum_buf);
1247 		if (len != accum_size)
1248 			err = got_ferror(outfile, GOT_ERR_IO);
1249 	}
1250 	rewind(outfile);
1251 	if (err == NULL)
1252 		*result_size = accum_size;
1253 	return err;
1254 }
1255 
1256 const struct got_error *
1257 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1258     struct got_delta_chain *deltas, struct got_pack *pack)
1259 {
1260 	const struct got_error *err = NULL;
1261 	struct got_delta *delta;
1262 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1263 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1264 	uint64_t max_size;
1265 	int n = 0;
1266 
1267 	*outbuf = NULL;
1268 	*outlen = 0;
1269 
1270 	if (STAILQ_EMPTY(&deltas->entries))
1271 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1272 
1273 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1274 	if (err)
1275 		return err;
1276 	accum_buf = malloc(max_size);
1277 	if (accum_buf == NULL)
1278 		return got_error_from_errno("malloc");
1279 
1280 	/* Deltas are ordered in ascending order. */
1281 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1282 		int cached = 1;
1283 		if (n == 0) {
1284 			size_t delta_data_offset;
1285 
1286 			/* Plain object types are the delta base. */
1287 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1288 			    delta->type != GOT_OBJ_TYPE_TREE &&
1289 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1290 			    delta->type != GOT_OBJ_TYPE_TAG) {
1291 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1292 				goto done;
1293 			}
1294 
1295 			delta_data_offset = delta->offset + delta->tslen;
1296 			if (delta_data_offset >= pack->filesize) {
1297 				err = got_error(GOT_ERR_PACK_OFFSET);
1298 				goto done;
1299 			}
1300 			if (pack->map) {
1301 				size_t mapoff = (size_t)delta_data_offset;
1302 				err = got_inflate_to_mem_mmap(&base_buf,
1303 				    &base_bufsz, NULL, NULL, pack->map,
1304 				    mapoff, pack->filesize - mapoff);
1305 			} else {
1306 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1307 				    == -1) {
1308 					err = got_error_from_errno("lseek");
1309 					goto done;
1310 				}
1311 				err = got_inflate_to_mem_fd(&base_buf,
1312 				    &base_bufsz, NULL, NULL, max_size,
1313 				    pack->fd);
1314 			}
1315 			if (err)
1316 				goto done;
1317 			n++;
1318 			continue;
1319 		}
1320 
1321 		got_delta_cache_get(&delta_buf, &delta_len,
1322 		    pack->delta_cache, delta->data_offset);
1323 		if (delta_buf == NULL) {
1324 			cached = 0;
1325 			err = read_delta_data(&delta_buf, &delta_len,
1326 			    delta->data_offset, pack);
1327 			if (err)
1328 				goto done;
1329 			err = got_delta_cache_add(pack->delta_cache,
1330 			    delta->data_offset, delta_buf, delta_len);
1331 			if (err == NULL)
1332 				cached = 1;
1333 			else if (err->code != GOT_ERR_NO_SPACE) {
1334 				free(delta_buf);
1335 				goto done;
1336 			}
1337 		}
1338 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1339 		    delta_buf, delta_len, accum_buf,
1340 		    &accum_size, max_size);
1341 		if (!cached)
1342 			free(delta_buf);
1343 		n++;
1344 		if (err)
1345 			goto done;
1346 
1347 		if (n < deltas->nentries) {
1348 			/* Accumulated delta becomes the new base. */
1349 			uint8_t *tmp = accum_buf;
1350 			/*
1351 			 * Base buffer switches roles with accumulation buffer.
1352 			 * Ensure it can hold the largest result in the delta
1353 			 * chain. Initial allocation might have been smaller.
1354 			 */
1355 			if (base_bufsz < max_size) {
1356 				uint8_t *p;
1357 				p = reallocarray(base_buf, 1, max_size);
1358 				if (p == NULL) {
1359 					err = got_error_from_errno(
1360 					    "reallocarray");
1361 					goto done;
1362 				}
1363 				base_buf = p;
1364 				base_bufsz = max_size;
1365 			}
1366 			accum_buf = base_buf;
1367 			base_buf = tmp;
1368 		}
1369 	}
1370 
1371 done:
1372 	free(base_buf);
1373 	if (err) {
1374 		free(accum_buf);
1375 		*outbuf = NULL;
1376 		*outlen = 0;
1377 	} else {
1378 		*outbuf = accum_buf;
1379 		*outlen = accum_size;
1380 	}
1381 	return err;
1382 }
1383 
1384 const struct got_error *
1385 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1386     FILE *outfile, FILE *base_file, FILE *accum_file)
1387 {
1388 	const struct got_error *err = NULL;
1389 
1390 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1391 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1392 
1393 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1394 		if (obj->pack_offset >= pack->filesize)
1395 			return got_error(GOT_ERR_PACK_OFFSET);
1396 
1397 		if (pack->map) {
1398 			size_t mapoff = (size_t)obj->pack_offset;
1399 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1400 			    pack->map, mapoff, pack->filesize - mapoff,
1401 			    outfile);
1402 		} else {
1403 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1404 				return got_error_from_errno("lseek");
1405 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1406 			    pack->fd, outfile);
1407 		}
1408 	} else
1409 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1410 		    &obj->deltas, pack, outfile, base_file, accum_file);
1411 
1412 	return err;
1413 }
1414 
1415 const struct got_error *
1416 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1417     struct got_object *obj, struct got_pack *pack)
1418 {
1419 	const struct got_error *err = NULL;
1420 
1421 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1422 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1423 
1424 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1425 		if (obj->pack_offset >= pack->filesize)
1426 			return got_error(GOT_ERR_PACK_OFFSET);
1427 		if (pack->map) {
1428 			size_t mapoff = (size_t)obj->pack_offset;
1429 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1430 			    pack->map, mapoff, pack->filesize - mapoff);
1431 		} else {
1432 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1433 				return got_error_from_errno("lseek");
1434 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1435 			    obj->size, pack->fd);
1436 		}
1437 	} else
1438 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1439 		    pack);
1440 
1441 	return err;
1442 }