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Date:: Sun Sep 9 14:09:01 2018 UTC
Message:: remove unused parameter of open_delta_object()
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1 /*
2  * Copyright (c) 2018 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/mman.h>
21 
22 #include <dirent.h>
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 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_repository.h"
37 #include "got_opentemp.h"
38 
39 #include "got_lib_sha1.h"
40 #include "got_lib_pack.h"
41 #include "got_lib_path.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_repository.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #define GOT_PACK_PREFIX		"pack-"
52 #define GOT_PACKFILE_SUFFIX	".pack"
53 #define GOT_PACKIDX_SUFFIX		".idx"
54 #define GOT_PACKFILE_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
55 				SHA1_DIGEST_STRING_LENGTH - 1 + \
56 				strlen(GOT_PACKFILE_SUFFIX))
57 #define GOT_PACKIDX_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
58 				SHA1_DIGEST_STRING_LENGTH - 1 + \
59 				strlen(GOT_PACKIDX_SUFFIX))
60 
61 #ifndef MIN
62 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
63 #endif
64 
65 static const struct got_error *
66 verify_fanout_table(uint32_t *fanout_table)
67 {
68 	int i;
69 
70 	for (i = 0; i < 0xff - 1; i++) {
71 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
72 			return got_error(GOT_ERR_BAD_PACKIDX);
73 	}
74 
75 	return NULL;
76 }
77 
78 static const struct got_error *
79 get_packfile_size(size_t *size, const char *path)
80 {
81 	struct stat sb;
82 	char *dot;
83 
84 	*size = 0;
85 
86 	dot = strrchr(path, '.');
87 	if (dot == NULL)
88 		return got_error(GOT_ERR_BAD_PATH);
89 
90 	/* Path must point to a pack index or to a pack file. */
91 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
92 		const struct got_error *err = NULL;
93 		char *path_pack;
94 		char base_path[PATH_MAX];
95 
96 		/* Convert pack index path to pack file path. */
97 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
98 			return got_error(GOT_ERR_NO_SPACE);
99 		dot = strrchr(base_path, '.');
100 		if (dot == NULL)
101 			return got_error(GOT_ERR_BAD_PATH);
102 		*dot = '\0';
103 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
104 			return got_error_from_errno();
105 
106 		if (stat(path_pack, &sb) != 0)
107 			err = got_error_from_errno();
108 		free(path_pack);
109 		if (err)
110 			return err;
111 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
112 		if (stat(path, &sb) != 0)
113 			return got_error_from_errno();
114 	} else
115 		return got_error(GOT_ERR_BAD_PATH);
116 
117 	*size = sb.st_size;
118 	return 0;
119 }
120 
121 const struct got_error *
122 got_packidx_init_hdr(struct got_packidx *p, int verify)
123 {
124 	const struct got_error *err = NULL;
125 	struct got_packidx_v2_hdr *h;
126 	SHA1_CTX ctx;
127 	uint8_t sha1[SHA1_DIGEST_LENGTH];
128 	size_t nobj, len_fanout, len_ids, offset, remain;
129 	ssize_t n;
130 
131 	SHA1Init(&ctx);
132 
133 	h = &p->hdr;
134 	offset = 0;
135 	remain = p->len;
136 
137 	if (remain < sizeof(*h->magic)) {
138 		err = got_error(GOT_ERR_BAD_PACKIDX);
139 		goto done;
140 	}
141 	if (p->map)
142 		h->magic = (uint32_t *)(p->map + offset);
143 	else {
144 		h->magic = malloc(sizeof(*h->magic));
145 		if (h->magic == NULL) {
146 			err = got_error_from_errno();
147 			goto done;
148 		}
149 		n = read(p->fd, h->magic, sizeof(*h->magic));
150 		if (n != sizeof(*h->magic)) {
151 			err = got_error(GOT_ERR_BAD_PACKIDX);
152 			goto done;
153 		}
154 	}
155 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
156 		err = got_error(GOT_ERR_BAD_PACKIDX);
157 		goto done;
158 	}
159 	offset += sizeof(*h->magic);
160 	remain -= sizeof(*h->magic);
161 
162 	if (verify)
163 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
164 
165 	if (remain < sizeof(*h->version)) {
166 		err = got_error(GOT_ERR_BAD_PACKIDX);
167 		goto done;
168 	}
169 	if (p->map)
170 		h->version = (uint32_t *)(p->map + offset);
171 	else {
172 		h->version = malloc(sizeof(*h->version));
173 		if (h->version == NULL) {
174 			err = got_error_from_errno();
175 			goto done;
176 		}
177 		n = read(p->fd, h->version, sizeof(*h->version));
178 		if (n != sizeof(*h->version)) {
179 			err = got_error(GOT_ERR_BAD_PACKIDX);
180 			goto done;
181 		}
182 	}
183 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
184 		err = got_error(GOT_ERR_BAD_PACKIDX);
185 		goto done;
186 	}
187 	offset += sizeof(*h->version);
188 	remain -= sizeof(*h->version);
189 
190 	if (verify)
191 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
192 
193 	len_fanout =
194 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
195 	if (remain < len_fanout) {
196 		err = got_error(GOT_ERR_BAD_PACKIDX);
197 		goto done;
198 	}
199 	if (p->map)
200 		h->fanout_table = (uint32_t *)(p->map + offset);
201 	else {
202 		h->fanout_table = malloc(len_fanout);
203 		if (h->fanout_table == NULL) {
204 			err = got_error_from_errno();
205 			goto done;
206 		}
207 		n = read(p->fd, h->fanout_table, len_fanout);
208 		if (n != len_fanout) {
209 			err = got_error(GOT_ERR_BAD_PACKIDX);
210 			goto done;
211 		}
212 	}
213 	err = verify_fanout_table(h->fanout_table);
214 	if (err)
215 		goto done;
216 	if (verify)
217 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
218 	offset += len_fanout;
219 	remain -= len_fanout;
220 
221 	nobj = betoh32(h->fanout_table[0xff]);
222 	len_ids = nobj * sizeof(*h->sorted_ids);
223 	if (len_ids <= nobj || len_ids > remain) {
224 		err = got_error(GOT_ERR_BAD_PACKIDX);
225 		goto done;
226 	}
227 	if (p->map)
228 		h->sorted_ids =
229 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
230 	else {
231 		h->sorted_ids = malloc(len_ids);
232 		if (h->sorted_ids == NULL) {
233 			err = got_error(GOT_ERR_BAD_PACKIDX);
234 			goto done;
235 		}
236 		n = read(p->fd, h->sorted_ids, len_ids);
237 		if (n != len_ids) {
238 			err = got_error(GOT_ERR_BAD_PACKIDX);
239 			goto done;
240 		}
241 	}
242 	if (verify)
243 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
244 	offset += len_ids;
245 	remain -= len_ids;
246 
247 	if (remain < nobj * sizeof(*h->crc32)) {
248 		err = got_error(GOT_ERR_BAD_PACKIDX);
249 		goto done;
250 	}
251 	if (p->map)
252 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
253 	else {
254 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
255 		if (h->crc32 == NULL) {
256 			err = got_error_from_errno();
257 			goto done;
258 		}
259 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
260 		if (n != nobj * sizeof(*h->crc32)) {
261 			err = got_error(GOT_ERR_BAD_PACKIDX);
262 			goto done;
263 		}
264 	}
265 	if (verify)
266 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
267 	remain -= nobj * sizeof(*h->crc32);
268 	offset += nobj * sizeof(*h->crc32);
269 
270 	if (remain < nobj * sizeof(*h->offsets)) {
271 		err = got_error(GOT_ERR_BAD_PACKIDX);
272 		goto done;
273 	}
274 	if (p->map)
275 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
276 	else {
277 		h->offsets = malloc(nobj * sizeof(*h->offsets));
278 		if (h->offsets == NULL) {
279 			err = got_error_from_errno();
280 			goto done;
281 		}
282 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
283 		if (n != nobj * sizeof(*h->offsets)) {
284 			err = got_error(GOT_ERR_BAD_PACKIDX);
285 			goto done;
286 		}
287 	}
288 	if (verify)
289 		SHA1Update(&ctx, (uint8_t *)h->offsets,
290 		    nobj * sizeof(*h->offsets));
291 	remain -= nobj * sizeof(*h->offsets);
292 	offset += nobj * sizeof(*h->offsets);
293 
294 	/* Large file offsets are contained only in files > 2GB. */
295 	if (p->len <= 0x80000000)
296 		goto checksum;
297 
298 	if (remain < nobj * sizeof(*h->large_offsets)) {
299 		err = got_error(GOT_ERR_BAD_PACKIDX);
300 		goto done;
301 	}
302 	if (p->map)
303 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
304 	else {
305 		h->offsets = malloc(nobj * sizeof(*h->large_offsets));
306 		if (h->offsets == NULL) {
307 			err = got_error_from_errno();
308 			goto done;
309 		}
310 		n = read(p->fd, h->large_offsets,
311 		    nobj * sizeof(*h->large_offsets));
312 		if (n != nobj * sizeof(*h->large_offsets)) {
313 			err = got_error(GOT_ERR_BAD_PACKIDX);
314 			goto done;
315 		}
316 	}
317 	if (verify)
318 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
319 		    nobj * sizeof(*h->large_offsets));
320 	remain -= nobj * sizeof(*h->large_offsets);
321 	offset += nobj * sizeof(*h->large_offsets);
322 
323 checksum:
324 	if (remain < sizeof(*h->trailer)) {
325 		err = got_error(GOT_ERR_BAD_PACKIDX);
326 		goto done;
327 	}
328 	if (p->map)
329 		h->trailer =
330 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
331 	else {
332 		h->trailer = malloc(sizeof(*h->trailer));
333 		if (h->trailer == NULL) {
334 			err = got_error_from_errno();
335 			goto done;
336 		}
337 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
338 		if (n != sizeof(*h->trailer)) {
339 			err = got_error(GOT_ERR_BAD_PACKIDX);
340 			goto done;
341 		}
342 	}
343 	if (verify) {
344 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
345 		SHA1Final(sha1, &ctx);
346 		if (memcmp(h->trailer->packidx_sha1, sha1,
347 		    SHA1_DIGEST_LENGTH) != 0)
348 			err = got_error(GOT_ERR_PACKIDX_CSUM);
349 	}
350 done:
351 	return err;
352 }
353 
354 const struct got_error *
355 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
356 {
357 	const struct got_error *err = NULL;
358 	struct got_packidx *p;
359 
360 	*packidx = NULL;
361 
362 	p = calloc(1, sizeof(*p));
363 	if (p == NULL)
364 		return got_error_from_errno();
365 
366 	p->fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
367 	if (p->fd == -1)
368 		return got_error_from_errno();
369 
370 	err = get_packfile_size(&p->len, path);
371 	if (err) {
372 		close(p->fd);
373 		free(p);
374 		return err;
375 	}
376 	if (p->len < sizeof(p->hdr)) {
377 		err = got_error(GOT_ERR_BAD_PACKIDX);
378 		close(p->fd);
379 		free(p);
380 		return err;
381 	}
382 
383 	p->path_packidx = strdup(path);
384 	if (p->path_packidx == NULL) {
385 		err = got_error_from_errno();
386 		goto done;
387 	}
388 
389 #ifndef GOT_PACK_NO_MMAP
390 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
391 	if (p->map == MAP_FAILED)
392 		p->map = NULL; /* fall back to read(2) */
393 #endif
394 
395 	err = got_packidx_init_hdr(p, verify);
396 done:
397 	if (err)
398 		got_packidx_close(p);
399 	else
400 		*packidx = p;
401 
402 	return err;
403 }
404 
405 const struct got_error *
406 got_packidx_close(struct got_packidx *packidx)
407 {
408 	const struct got_error *err = NULL;
409 
410 	free(packidx->path_packidx);
411 	if (packidx->map) {
412 		if (munmap(packidx->map, packidx->len) == -1)
413 			err = got_error_from_errno();
414 	} else {
415 		free(packidx->hdr.magic);
416 		free(packidx->hdr.version);
417 		free(packidx->hdr.fanout_table);
418 		free(packidx->hdr.sorted_ids);
419 		free(packidx->hdr.crc32);
420 		free(packidx->hdr.offsets);
421 		free(packidx->hdr.large_offsets);
422 		free(packidx->hdr.trailer);
423 	}
424 	close(packidx->fd);
425 	free(packidx);
426 
427 	return err;
428 }
429 
430 static int
431 is_packidx_filename(const char *name, size_t len)
432 {
433 	if (len != GOT_PACKIDX_NAMELEN)
434 		return 0;
435 
436 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
437 		return 0;
438 
439 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
440 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
441 		return 0;
442 
443 	return 1;
444 }
445 
446 static off_t
447 get_object_offset(struct got_packidx *packidx, int idx)
448 {
449 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
450 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
451 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
452 		uint64_t loffset;
453 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
454 		if (idx < 0 || idx > totobj ||
455 		    packidx->hdr.large_offsets == NULL)
456 			return -1;
457 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
458 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
459 	}
460 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
461 }
462 
463 static int
464 get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
465 {
466 	u_int8_t id0 = id->sha1[0];
467 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
468 	int left = 0, right = totobj - 1;
469 
470 	if (id0 > 0)
471 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
472 
473 	while (left <= right) {
474 		struct got_packidx_object_id *oid;
475 		int i, cmp;
476 
477 		i = ((left + right) / 2);
478 		oid = &packidx->hdr.sorted_ids[i];
479 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
480 		if (cmp == 0)
481 			return i;
482 		else if (cmp > 0)
483 			left = i + 1;
484 		else if (cmp < 0)
485 			right = i - 1;
486 	}
487 
488 	return -1;
489 }
490 
491 static const struct got_error *
492 cache_packidx(struct got_packidx *packidx, struct got_repository *repo)
493 {
494 	const struct got_error *err = NULL;
495 	int i;
496 
497 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
498 		if (repo->packidx_cache[i] == NULL)
499 			break;
500 	}
501 
502 	if (i == nitems(repo->packidx_cache)) {
503 		err = got_packidx_close(repo->packidx_cache[i - 1]);
504 		if (err)
505 			return err;
506 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
507 		    sizeof(repo->packidx_cache) -
508 		    sizeof(repo->packidx_cache[0]));
509 		i = 0;
510 	}
511 
512 	repo->packidx_cache[i] = packidx;
513 	return NULL;
514 }
515 
516 static const struct got_error *
517 search_packidx(struct got_packidx **packidx, int *idx,
518     struct got_repository *repo, struct got_object_id *id)
519 {
520 	const struct got_error *err;
521 	char *path_packdir;
522 	DIR *packdir;
523 	struct dirent *dent;
524 	char *path_packidx;
525 	int i;
526 
527 	/* Search pack index cache. */
528 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
529 		if (repo->packidx_cache[i] == NULL)
530 			break;
531 		*idx = get_object_idx(repo->packidx_cache[i], id);
532 		if (*idx != -1) {
533 			*packidx = repo->packidx_cache[i];
534 			return NULL;
535 		}
536 	}
537 	/* No luck. Search the filesystem. */
538 
539 	path_packdir = got_repo_get_path_objects_pack(repo);
540 	if (path_packdir == NULL)
541 		return got_error_from_errno();
542 
543 	packdir = opendir(path_packdir);
544 	if (packdir == NULL) {
545 		err = got_error_from_errno();
546 		goto done;
547 	}
548 
549 	while ((dent = readdir(packdir)) != NULL) {
550 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
551 			continue;
552 
553 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
554 		    dent->d_name) == -1) {
555 			err = got_error_from_errno();
556 			goto done;
557 		}
558 
559 		err = got_packidx_open(packidx, path_packidx, 0);
560 		free(path_packidx);
561 		if (err)
562 			goto done;
563 
564 		*idx = get_object_idx(*packidx, id);
565 		if (*idx != -1) {
566 			err = NULL; /* found the object */
567 			err = cache_packidx(*packidx, repo);
568 			goto done;
569 		}
570 
571 		err = got_packidx_close(*packidx);
572 		*packidx = NULL;
573 		if (err)
574 			goto done;
575 	}
576 
577 	err = got_error(GOT_ERR_NO_OBJ);
578 done:
579 	free(path_packdir);
580 	if (packdir && closedir(packdir) != 0 && err == 0)
581 		err = got_error_from_errno();
582 	return err;
583 }
584 
585 static const struct got_error *
586 get_packfile_path(char **path_packfile, struct got_packidx *packidx)
587 {
588 	size_t size;
589 
590 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
591 	size = strlen(packidx->path_packidx) + 2;
592 	if (size < GOT_PACKFILE_NAMELEN + 1)
593 		return got_error(GOT_ERR_BAD_PATH);
594 
595 	*path_packfile = calloc(size, sizeof(**path_packfile));
596 	if (*path_packfile == NULL)
597 		return got_error_from_errno();
598 
599 	/* Copy up to and excluding ".idx". */
600 	if (strlcpy(*path_packfile, packidx->path_packidx,
601 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
602 		return got_error(GOT_ERR_NO_SPACE);
603 
604 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
605 		return got_error(GOT_ERR_NO_SPACE);
606 
607 	return NULL;
608 }
609 
610 static const struct got_error *
611 read_packfile_hdr(int fd, struct got_packidx *packidx)
612 {
613 	const struct got_error *err = NULL;
614 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
615 	struct got_packfile_hdr hdr;
616 	ssize_t n;
617 
618 	n = read(fd, &hdr, sizeof(hdr));
619 	if (n < 0)
620 		return got_error_from_errno();
621 	if (n != sizeof(hdr))
622 		return got_error(GOT_ERR_BAD_PACKFILE);
623 
624 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
625 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
626 	    betoh32(hdr.nobjects) != totobj)
627 		err = got_error(GOT_ERR_BAD_PACKFILE);
628 
629 	return err;
630 }
631 
632 static const struct got_error *
633 open_packfile(int *fd, const char *path_packfile, struct got_packidx *packidx)
634 {
635 	const struct got_error *err = NULL;
636 
637 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
638 	if (*fd == -1)
639 		return got_error_from_errno();
640 
641 	if (packidx) {
642 		err = read_packfile_hdr(*fd, packidx);
643 		if (err) {
644 			close(*fd);
645 			*fd = -1;
646 		}
647 	}
648 	return err;
649 }
650 
651 const struct got_error *
652 got_pack_close(struct got_pack *pack)
653 {
654 	const struct got_error *err = NULL;
655 
656 	if (pack->map && munmap(pack->map, pack->filesize) == -1)
657 		err = got_error_from_errno();
658 	close(pack->fd);
659 	pack->fd = -1;
660 	free(pack->path_packfile);
661 	pack->path_packfile = NULL;
662 	pack->filesize = 0;
663 
664 	return err;
665 }
666 
667 static const struct got_error *
668 cache_pack(struct got_pack **packp, const char *path_packfile,
669     struct got_packidx *packidx, struct got_repository *repo)
670 {
671 	const struct got_error *err = NULL;
672 	struct got_pack *pack = NULL;
673 	int i;
674 
675 	if (packp)
676 		*packp = NULL;
677 
678 	for (i = 0; i < nitems(repo->packs); i++) {
679 		pack = &repo->packs[i];
680 		if (pack->path_packfile == NULL)
681 			break;
682 		if (strcmp(pack->path_packfile, path_packfile) == 0)
683 			return NULL;
684 	}
685 
686 	if (i == nitems(repo->packs) - 1) {
687 		err = got_pack_close(&repo->packs[i - 1]);
688 		if (err)
689 			return err;
690 		memmove(&repo->packs[1], &repo->packs[0],
691 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
692 		i = 0;
693 	}
694 
695 	pack = &repo->packs[i];
696 
697 	pack->path_packfile = strdup(path_packfile);
698 	if (pack->path_packfile == NULL) {
699 		err = got_error_from_errno();
700 		goto done;
701 	}
702 
703 	err = open_packfile(&pack->fd, path_packfile, packidx);
704 	if (err)
705 		goto done;
706 
707 	err = get_packfile_size(&pack->filesize, path_packfile);
708 	if (err)
709 		goto done;
710 
711 #ifndef GOT_PACK_NO_MMAP
712 	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
713 	    pack->fd, 0);
714 	if (pack->map == MAP_FAILED)
715 		pack->map = NULL; /* fall back to read(2) */
716 #endif
717 done:
718 	if (err) {
719 		if (pack) {
720 			free(pack->path_packfile);
721 			memset(pack, 0, sizeof(*pack));
722 		}
723 	} else if (packp)
724 		*packp = pack;
725 	return err;
726 }
727 
728 struct got_pack *
729 get_cached_pack(const char *path_packfile, struct got_repository *repo)
730 {
731 	struct got_pack *pack = NULL;
732 	int i;
733 
734 	for (i = 0; i < nitems(repo->packs); i++) {
735 		pack = &repo->packs[i];
736 		if (pack->path_packfile == NULL)
737 			break;
738 		if (strcmp(pack->path_packfile, path_packfile) == 0)
739 			return pack;
740 	}
741 
742 	return NULL;
743 }
744 
745 static const struct got_error *
746 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
747     struct got_pack *pack, off_t offset)
748 {
749 	uint8_t t = 0;
750 	uint64_t s = 0;
751 	uint8_t sizeN;
752 	size_t mapoff = 0;
753 	int i = 0;
754 
755 	*len = 0;
756 
757 	if (offset >= pack->filesize)
758 		return got_error(GOT_ERR_PACK_OFFSET);
759 
760 	if (pack->map) {
761 		mapoff = (size_t)offset;
762 	} else {
763 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
764 			return got_error_from_errno();
765 	}
766 
767 	do {
768 		/* We do not support size values which don't fit in 64 bit. */
769 		if (i > 9)
770 			return got_error(GOT_ERR_NO_SPACE);
771 
772 		if (pack->map) {
773 			sizeN = *(pack->map + mapoff);
774 			mapoff += sizeof(sizeN);
775 		} else {
776 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
777 			if (n < 0)
778 				return got_error_from_errno();
779 			if (n != sizeof(sizeN))
780 				return got_error(GOT_ERR_BAD_PACKFILE);
781 		}
782 		*len += sizeof(sizeN);
783 
784 		if (i == 0) {
785 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
786 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
787 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
788 		} else {
789 			size_t shift = 4 + 7 * (i - 1);
790 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
791 		}
792 		i++;
793 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
794 
795 	*type = t;
796 	*size = s;
797 	return NULL;
798 }
799 
800 static const struct got_error *
801 open_plain_object(struct got_object **obj, const char *path_packfile,
802     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
803 {
804 	*obj = calloc(1, sizeof(**obj));
805 	if (*obj == NULL)
806 		return got_error_from_errno();
807 
808 	(*obj)->path_packfile = strdup(path_packfile);
809 	if ((*obj)->path_packfile == NULL) {
810 		const struct got_error *err = got_error_from_errno();
811 		free(*obj);
812 		*obj = NULL;
813 		return err;
814 	}
815 
816 	(*obj)->type = type;
817 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
818 	(*obj)->hdrlen = 0;
819 	(*obj)->size = size;
820 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
821 	(*obj)->pack_offset = offset;
822 
823 	return NULL;
824 }
825 
826 static const struct got_error *
827 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
828     off_t delta_offset)
829 {
830 	int64_t o = 0;
831 	uint8_t offN;
832 	int i = 0;
833 
834 	*len = 0;
835 
836 	do {
837 		/* We do not support offset values which don't fit in 64 bit. */
838 		if (i > 8)
839 			return got_error(GOT_ERR_NO_SPACE);
840 
841 		if (pack->map) {
842 			size_t mapoff;
843 			if (delta_offset >= pack->filesize)
844 				return got_error(GOT_ERR_PACK_OFFSET);
845 			mapoff = (size_t)delta_offset + *len;
846 			offN = *(pack->map + mapoff);
847 		} else {
848 			ssize_t n;
849 			n = read(pack->fd, &offN, sizeof(offN));
850 			if (n < 0)
851 				return got_error_from_errno();
852 			if (n != sizeof(offN))
853 				return got_error(GOT_ERR_BAD_PACKFILE);
854 		}
855 		*len += sizeof(offN);
856 
857 		if (i == 0)
858 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
859 		else {
860 			o++;
861 			o <<= 7;
862 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
863 		}
864 		i++;
865 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
866 
867 	*offset = o;
868 	return NULL;
869 }
870 
871 static const struct got_error *
872 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
873     off_t offset, int tslen)
874 {
875 	const struct got_error *err;
876 	int64_t negoffset;
877 	size_t negofflen;
878 
879 	*len = 0;
880 
881 	err = parse_negative_offset(&negoffset, &negofflen, pack,
882 	    offset + tslen);
883 	if (err)
884 		return err;
885 
886 	/* Compute the base object's offset (must be in the same pack file). */
887 	*base_offset = (offset - negoffset);
888 	if (*base_offset <= 0)
889 		return got_error(GOT_ERR_BAD_PACKFILE);
890 
891 	*len = negofflen;
892 	return NULL;
893 }
894 
895 static const struct got_error *
896 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
897     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
898 
899 static const struct got_error *
900 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
901     int delta_type, size_t delta_size, size_t delta_data_offset,
902     uint8_t *delta_buf, size_t delta_len)
903 {
904 	struct got_delta *delta;
905 
906 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
907 	    delta_data_offset, delta_buf,
908 	    delta_len);
909 	if (delta == NULL)
910 		return got_error_from_errno();
911 	/* delta is freed in got_object_close() */
912 	deltas->nentries++;
913 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
914 	return NULL;
915 }
916 
917 static const struct got_error *
918 resolve_offset_delta(struct got_delta_chain *deltas,
919     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
920     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
921 
922 {
923 	const struct got_error *err;
924 	off_t base_offset;
925 	uint8_t base_type;
926 	uint64_t base_size;
927 	size_t base_tslen;
928 	off_t delta_data_offset;
929 	uint8_t *delta_buf;
930 	size_t delta_len, consumed;
931 
932 	err = parse_offset_delta(&base_offset, &consumed, pack,
933 	    delta_offset, tslen);
934 	if (err)
935 		return err;
936 
937 	delta_data_offset = delta_offset + tslen + consumed;
938 	if (delta_data_offset >= pack->filesize)
939 		return got_error(GOT_ERR_PACK_OFFSET);
940 
941 	if (pack->map == NULL) {
942 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
943 		if (delta_data_offset == -1)
944 			return got_error_from_errno();
945 	}
946 
947 	if (pack->map) {
948 		size_t mapoff = (size_t)delta_data_offset;
949 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
950 		    mapoff, pack->filesize - mapoff);
951 		if (err)
952 			return err;
953 	} else {
954 
955 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
956 		if (err)
957 			return err;
958 	}
959 
960 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
961 	    delta_data_offset, delta_buf, delta_len);
962 	if (err)
963 		goto done;
964 
965 	/* An offset delta must be in the same packfile. */
966 	if (base_offset >= pack->filesize) {
967 		err = got_error(GOT_ERR_PACK_OFFSET);
968 		goto done;
969 	}
970 
971 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
972 	    pack, base_offset);
973 	if (err)
974 		goto done;
975 
976 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
977 	    base_tslen, base_type, base_size, recursion - 1);
978 done:
979 	if (err)
980 		free(delta_buf);
981 	return err;
982 }
983 
984 static const struct got_error *
985 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
986     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
987     size_t delta_size, unsigned int recursion)
988 {
989 	const struct got_error *err;
990 	struct got_object_id id;
991 	int idx;
992 	off_t base_offset;
993 	uint8_t base_type;
994 	uint64_t base_size;
995 	size_t base_tslen;
996 	off_t delta_data_offset;
997 	uint8_t *delta_buf = NULL;
998 	size_t delta_len;
999 
1000 	if (delta_offset >= pack->filesize)
1001 		return got_error(GOT_ERR_PACK_OFFSET);
1002 	delta_data_offset = delta_offset + tslen;
1003 	if (delta_data_offset >= pack->filesize)
1004 		return got_error(GOT_ERR_PACK_OFFSET);
1005 
1006 	if (pack->map == NULL) {
1007 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1008 		if (delta_data_offset == -1)
1009 			return got_error_from_errno();
1010 	}
1011 
1012 
1013 	if (pack->map) {
1014 		size_t mapoff = (size_t)delta_data_offset;
1015 		memcpy(&id, pack->map + mapoff, sizeof(id));
1016 		mapoff += sizeof(id);
1017 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
1018 		    mapoff, pack->filesize - mapoff);
1019 		if (err)
1020 			goto done;
1021 	} else {
1022 		ssize_t n = read(pack->fd, &id, sizeof(id));
1023 		if (n < 0)
1024 			return got_error_from_errno();
1025 		if (n != sizeof(id))
1026 			return got_error(GOT_ERR_BAD_PACKFILE);
1027 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
1028 		if (err)
1029 			goto done;
1030 	}
1031 
1032 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1033 	    delta_data_offset, delta_buf, delta_len);
1034 	if (err)
1035 		goto done;
1036 
1037 	/* Delta base must be in the same pack file. */
1038 	idx = get_object_idx(packidx, &id);
1039 	if (idx == -1) {
1040 		err = got_error(GOT_ERR_BAD_PACKFILE);
1041 		goto done;
1042 	}
1043 
1044 	base_offset = get_object_offset(packidx, idx);
1045 	if (base_offset == (uint64_t)-1) {
1046 		err = got_error(GOT_ERR_BAD_PACKIDX);
1047 		goto done;
1048 	}
1049 
1050 	if (base_offset >= pack->filesize) {
1051 		err = got_error(GOT_ERR_PACK_OFFSET);
1052 		goto done;
1053 	}
1054 
1055 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
1056 	    pack, base_offset);
1057 	if (err)
1058 		goto done;
1059 
1060 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
1061 	    base_tslen, base_type, base_size, recursion - 1);
1062 done:
1063 	if (err)
1064 		free(delta_buf);
1065 	return err;
1066 }
1067 
1068 static const struct got_error *
1069 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
1070     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1071     size_t delta_size, unsigned int recursion)
1072 {
1073 	const struct got_error *err = NULL;
1074 
1075 	if (--recursion == 0)
1076 		return got_error(GOT_ERR_RECURSION);
1077 
1078 	switch (delta_type) {
1079 	case GOT_OBJ_TYPE_COMMIT:
1080 	case GOT_OBJ_TYPE_TREE:
1081 	case GOT_OBJ_TYPE_BLOB:
1082 	case GOT_OBJ_TYPE_TAG:
1083 		/* Plain types are the final delta base. Recursion ends. */
1084 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1085 		    delta_size, 0, NULL, 0);
1086 		break;
1087 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1088 		err = resolve_offset_delta(deltas, packidx, pack,
1089 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1090 		break;
1091 	case GOT_OBJ_TYPE_REF_DELTA:
1092 		err = resolve_ref_delta(deltas, packidx, pack,
1093 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1094 		break;
1095 	default:
1096 		return got_error(GOT_ERR_OBJ_TYPE);
1097 	}
1098 
1099 	return err;
1100 }
1101 
1102 static const struct got_error *
1103 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1104     struct got_pack *pack, struct got_object_id *id, off_t offset,
1105     size_t tslen, int delta_type, size_t delta_size)
1106 {
1107 	const struct got_error *err = NULL;
1108 	int resolved_type;
1109 
1110 	*obj = calloc(1, sizeof(**obj));
1111 	if (*obj == NULL)
1112 		return got_error_from_errno();
1113 
1114 	(*obj)->flags = 0;
1115 	(*obj)->hdrlen = 0;
1116 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1117 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1118 	(*obj)->pack_offset = offset + tslen;
1119 
1120 	(*obj)->path_packfile = strdup(pack->path_packfile);
1121 	if ((*obj)->path_packfile == NULL) {
1122 		err = got_error_from_errno();
1123 		goto done;
1124 	}
1125 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1126 
1127 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
1128 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1129 
1130 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
1131 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
1132 	if (err)
1133 		goto done;
1134 
1135 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1136 	if (err)
1137 		goto done;
1138 	(*obj)->type = resolved_type;
1139 
1140 done:
1141 	if (err) {
1142 		got_object_close(*obj);
1143 		*obj = NULL;
1144 	}
1145 	return err;
1146 }
1147 
1148 static const struct got_error *
1149 open_packed_object(struct got_object **obj, struct got_repository *repo,
1150     struct got_packidx *packidx, int idx, struct got_object_id *id)
1151 {
1152 	const struct got_error *err = NULL;
1153 	off_t offset;
1154 	char *path_packfile;
1155 	struct got_pack *pack;
1156 	uint8_t type;
1157 	uint64_t size;
1158 	size_t tslen;
1159 
1160 	*obj = NULL;
1161 
1162 	offset = get_object_offset(packidx, idx);
1163 	if (offset == (uint64_t)-1)
1164 		return got_error(GOT_ERR_BAD_PACKIDX);
1165 
1166 	err = get_packfile_path(&path_packfile, packidx);
1167 	if (err)
1168 		return err;
1169 
1170 	pack = get_cached_pack(path_packfile, repo);
1171 	if (pack == NULL) {
1172 		err = cache_pack(&pack, path_packfile, packidx, repo);
1173 		if (err)
1174 			goto done;
1175 	}
1176 
1177 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
1178 	if (err)
1179 		goto done;
1180 
1181 	switch (type) {
1182 	case GOT_OBJ_TYPE_COMMIT:
1183 	case GOT_OBJ_TYPE_TREE:
1184 	case GOT_OBJ_TYPE_BLOB:
1185 	case GOT_OBJ_TYPE_TAG:
1186 		err = open_plain_object(obj, path_packfile, id, type,
1187 		    offset + tslen, size);
1188 		break;
1189 
1190 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1191 	case GOT_OBJ_TYPE_REF_DELTA:
1192 		err = open_delta_object(obj, packidx, pack, id, offset,
1193 		    tslen, type, size);
1194 		break;
1195 
1196 	default:
1197 		err = got_error(GOT_ERR_OBJ_TYPE);
1198 		goto done;
1199 	}
1200 done:
1201 	free(path_packfile);
1202 	return err;
1203 }
1204 
1205 const struct got_error *
1206 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1207     struct got_repository *repo)
1208 {
1209 	const struct got_error *err = NULL;
1210 	struct got_packidx *packidx = NULL;
1211 	int idx;
1212 
1213 	err = search_packidx(&packidx, &idx, repo, id);
1214 	if (err)
1215 		return err;
1216 
1217 	err = open_packed_object(obj, repo, packidx, idx, id);
1218 	if (err)
1219 		return err;
1220 
1221 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1222 	return err;
1223 }
1224 
1225 static const struct got_error *
1226 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1227 {
1228 	struct got_delta *delta;
1229 	uint64_t base_size = 0, result_size = 0;
1230 
1231 	*max_size = 0;
1232 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1233 		/* Plain object types are the delta base. */
1234 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1235 		    delta->type != GOT_OBJ_TYPE_TREE &&
1236 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1237 		    delta->type != GOT_OBJ_TYPE_TAG) {
1238 			const struct got_error *err;
1239 			err = got_delta_get_sizes(&base_size, &result_size,
1240 			    delta->delta_buf, delta->delta_len);
1241 			if (err)
1242 				return err;
1243 		} else
1244 			base_size = delta->size;
1245 		if (base_size > *max_size)
1246 			*max_size = base_size;
1247 		if (result_size > *max_size)
1248 			*max_size = result_size;
1249 	}
1250 
1251 	return NULL;
1252 }
1253 
1254 static const struct got_error *
1255 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1256     struct got_pack *pack, FILE *outfile)
1257 {
1258 	const struct got_error *err = NULL;
1259 	struct got_delta *delta;
1260 	FILE *base_file = NULL, *accum_file = NULL;
1261 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1262 	size_t accum_size = 0;
1263 	uint64_t max_size;
1264 	int n = 0;
1265 
1266 	*result_size = 0;
1267 
1268 	if (SIMPLEQ_EMPTY(&deltas->entries))
1269 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1270 
1271 	/* We process small enough files entirely in memory for speed. */
1272 	err = get_delta_chain_max_size(&max_size, deltas);
1273 	if (err)
1274 		return err;
1275 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1276 		accum_buf = malloc(max_size);
1277 		if (accum_buf == NULL)
1278 			return got_error_from_errno();
1279 	} else {
1280 		base_file = got_opentemp();
1281 		if (base_file == NULL)
1282 			return got_error_from_errno();
1283 
1284 		accum_file = got_opentemp();
1285 		if (accum_file == NULL) {
1286 			err = got_error_from_errno();
1287 			fclose(base_file);
1288 			return err;
1289 		}
1290 	}
1291 
1292 	/* Deltas are ordered in ascending order. */
1293 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1294 		if (n == 0) {
1295 			size_t base_len, mapoff;
1296 			off_t delta_data_offset;
1297 
1298 			/* Plain object types are the delta base. */
1299 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1300 			    delta->type != GOT_OBJ_TYPE_TREE &&
1301 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1302 			    delta->type != GOT_OBJ_TYPE_TAG) {
1303 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1304 				goto done;
1305 			}
1306 
1307 			delta_data_offset = delta->offset + delta->tslen;
1308 			if (delta_data_offset >= pack->filesize) {
1309 				err = got_error(GOT_ERR_PACK_OFFSET);
1310 				goto done;
1311 			}
1312 			if (pack->map == NULL) {
1313 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1314 				    == -1) {
1315 					err = got_error_from_errno();
1316 					goto done;
1317 				}
1318 			}
1319 			if (base_file) {
1320 				if (pack->map) {
1321 					mapoff = (size_t)delta_data_offset;
1322 					err = got_inflate_to_file_mmap(
1323 					    &base_len, pack->map, mapoff,
1324 					    pack->filesize - mapoff, base_file);
1325 				} else
1326 					err = got_inflate_to_file_fd(&base_len,
1327 					    pack->fd, base_file);
1328 			} else {
1329 				if (pack->map) {
1330 					mapoff = (size_t)delta_data_offset;
1331 					err = got_inflate_to_mem_mmap(&base_buf,
1332 					    &base_len, pack->map, mapoff,
1333 					    pack->filesize - mapoff);
1334 				} else
1335 					err = got_inflate_to_mem_fd(&base_buf,
1336 					    &base_len, pack->fd);
1337 				if (base_len < max_size) {
1338 					uint8_t *p;
1339 					p = reallocarray(base_buf, 1, max_size);
1340 					if (p == NULL) {
1341 						err = got_error_from_errno();
1342 						goto done;
1343 					}
1344 					base_buf = p;
1345 				}
1346 			}
1347 			if (err)
1348 				goto done;
1349 			n++;
1350 			if (base_file)
1351 				rewind(base_file);
1352 			continue;
1353 		}
1354 
1355 		if (base_buf) {
1356 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1357 			    delta->delta_len, accum_buf, &accum_size);
1358 			n++;
1359 		} else {
1360 			err = got_delta_apply(base_file, delta->delta_buf,
1361 			    delta->delta_len,
1362 			    /* Final delta application writes to output file. */
1363 			    ++n < deltas->nentries ? accum_file : outfile,
1364 			    &accum_size);
1365 		}
1366 		if (err)
1367 			goto done;
1368 
1369 		if (n < deltas->nentries) {
1370 			/* Accumulated delta becomes the new base. */
1371 			if (base_buf) {
1372 				uint8_t *tmp = accum_buf;
1373 				accum_buf = base_buf;
1374 				base_buf = tmp;
1375 			} else {
1376 				FILE *tmp = accum_file;
1377 				accum_file = base_file;
1378 				base_file = tmp;
1379 				rewind(base_file);
1380 				rewind(accum_file);
1381 			}
1382 		}
1383 	}
1384 
1385 done:
1386 	free(base_buf);
1387 	if (accum_buf) {
1388 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1389 		free(accum_buf);
1390 		if (len != accum_size)
1391 			err = got_ferror(outfile, GOT_ERR_IO);
1392 	}
1393 	if (base_file)
1394 		fclose(base_file);
1395 	if (accum_file)
1396 		fclose(accum_file);
1397 	rewind(outfile);
1398 	if (err == NULL)
1399 		*result_size = accum_size;
1400 	return err;
1401 }
1402 
1403 static const struct got_error *
1404 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1405     struct got_delta_chain *deltas, struct got_pack *pack)
1406 {
1407 	const struct got_error *err = NULL;
1408 	struct got_delta *delta;
1409 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1410 	size_t accum_size;
1411 	uint64_t max_size;
1412 	int n = 0;
1413 
1414 	*outbuf = NULL;
1415 	*outlen = 0;
1416 
1417 	if (SIMPLEQ_EMPTY(&deltas->entries))
1418 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1419 
1420 	err = get_delta_chain_max_size(&max_size, deltas);
1421 	if (err)
1422 		return err;
1423 	accum_buf = malloc(max_size);
1424 	if (accum_buf == NULL)
1425 		return got_error_from_errno();
1426 
1427 	/* Deltas are ordered in ascending order. */
1428 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1429 		if (n == 0) {
1430 			size_t base_len;
1431 			size_t delta_data_offset;
1432 
1433 			/* Plain object types are the delta base. */
1434 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1435 			    delta->type != GOT_OBJ_TYPE_TREE &&
1436 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1437 			    delta->type != GOT_OBJ_TYPE_TAG) {
1438 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1439 				goto done;
1440 			}
1441 
1442 			delta_data_offset = delta->offset + delta->tslen;
1443 			if (delta_data_offset >= pack->filesize) {
1444 				err = got_error(GOT_ERR_PACK_OFFSET);
1445 				goto done;
1446 			}
1447 			if (pack->map) {
1448 				size_t mapoff = (size_t)delta_data_offset;
1449 				err = got_inflate_to_mem_mmap(&base_buf,
1450 				    &base_len, pack->map, mapoff,
1451 				    pack->filesize - mapoff);
1452 			} else {
1453 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1454 				    == -1) {
1455 					err = got_error_from_errno();
1456 					goto done;
1457 				}
1458 				err = got_inflate_to_mem_fd(&base_buf,
1459 				    &base_len, pack->fd);
1460 			}
1461 			if (err)
1462 				goto done;
1463 			if (base_len < max_size) {
1464 				uint8_t *p;
1465 				p = reallocarray(base_buf, 1, max_size);
1466 				if (p == NULL) {
1467 					err = got_error_from_errno();
1468 					goto done;
1469 				}
1470 				base_buf = p;
1471 			}
1472 			n++;
1473 			continue;
1474 		}
1475 
1476 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1477 		    delta->delta_len, accum_buf, &accum_size);
1478 		n++;
1479 		if (err)
1480 			goto done;
1481 
1482 		if (n < deltas->nentries) {
1483 			/* Accumulated delta becomes the new base. */
1484 			uint8_t *tmp = accum_buf;
1485 			accum_buf = base_buf;
1486 			base_buf = tmp;
1487 		}
1488 	}
1489 
1490 done:
1491 	free(base_buf);
1492 	if (err) {
1493 		free(accum_buf);
1494 		*outbuf = NULL;
1495 		*outlen = 0;
1496 	} else {
1497 		*outbuf = accum_buf;
1498 		*outlen = accum_size;
1499 	}
1500 	return err;
1501 }
1502 
1503 const struct got_error *
1504 got_packfile_extract_object(FILE **f, struct got_object *obj,
1505     struct got_repository *repo)
1506 {
1507 	const struct got_error *err = NULL;
1508 	struct got_pack *pack;
1509 
1510 	*f = NULL;
1511 
1512 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1513 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1514 
1515 	pack = get_cached_pack(obj->path_packfile, repo);
1516 	if (pack == NULL) {
1517 		err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1518 		if (err)
1519 			return err;
1520 	}
1521 
1522 	*f = got_opentemp();
1523 	if (*f == NULL) {
1524 		err = got_error_from_errno();
1525 		goto done;
1526 	}
1527 
1528 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1529 		if (obj->pack_offset >= pack->filesize) {
1530 			err = got_error(GOT_ERR_PACK_OFFSET);
1531 			goto done;
1532 		}
1533 
1534 		if (pack->map) {
1535 			size_t mapoff = (size_t)obj->pack_offset;
1536 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1537 			    mapoff, pack->filesize - mapoff, *f);
1538 		} else {
1539 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1540 				err = got_error_from_errno();
1541 				goto done;
1542 			}
1543 			err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1544 		}
1545 	} else
1546 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1547 		    *f);
1548 done:
1549 	if (err && *f) {
1550 		fclose(*f);
1551 		*f = NULL;
1552 	}
1553 	return err;
1554 }
1555 
1556 const struct got_error *
1557 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1558     struct got_object *obj, struct got_repository *repo)
1559 {
1560 	const struct got_error *err = NULL;
1561 	struct got_pack *pack;
1562 
1563 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1564 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1565 
1566 	pack = get_cached_pack(obj->path_packfile, repo);
1567 	if (pack == NULL) {
1568 		err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1569 		if (err)
1570 			goto done;
1571 	}
1572 
1573 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1574 		if (obj->pack_offset >= pack->filesize) {
1575 			err = got_error(GOT_ERR_PACK_OFFSET);
1576 			goto done;
1577 		}
1578 		if (pack->map) {
1579 			size_t mapoff = (size_t)obj->pack_offset;
1580 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1581 			    mapoff, pack->filesize - mapoff);
1582 		} else {
1583 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1584 				err = got_error_from_errno();
1585 				goto done;
1586 			}
1587 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1588 		}
1589 	} else
1590 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1591 done:
1592 	return err;
1593 }