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,
634     struct got_repository *repo, struct got_packidx *packidx)
635 {
636 	const struct got_error *err = NULL;
637 
638 	*fd = open(path_packfile, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
639 	if (*fd == -1)
640 		return got_error_from_errno();
641 
642 	if (packidx) {
643 		err = read_packfile_hdr(*fd, packidx);
644 		if (err) {
645 			close(*fd);
646 			*fd = -1;
647 		}
648 	}
649 	return err;
650 }
651 
652 const struct got_error *
653 got_pack_close(struct got_pack *pack)
654 {
655 	const struct got_error *err = NULL;
656 
657 	if (pack->map && munmap(pack->map, pack->filesize) == -1)
658 		err = got_error_from_errno();
659 	close(pack->fd);
660 	pack->fd = -1;
661 	free(pack->path_packfile);
662 	pack->path_packfile = NULL;
663 	pack->filesize = 0;
664 
665 	return err;
666 }
667 
668 static const struct got_error *
669 cache_pack(struct got_pack **packp, const char *path_packfile,
670     struct got_packidx *packidx, struct got_repository *repo)
671 {
672 	const struct got_error *err = NULL;
673 	struct got_pack *pack = NULL;
674 	int i;
675 
676 	if (packp)
677 		*packp = NULL;
678 
679 	for (i = 0; i < nitems(repo->packs); i++) {
680 		pack = &repo->packs[i];
681 		if (pack->path_packfile == NULL)
682 			break;
683 		if (strcmp(pack->path_packfile, path_packfile) == 0)
684 			return NULL;
685 	}
686 
687 	if (i == nitems(repo->packs) - 1) {
688 		err = got_pack_close(&repo->packs[i - 1]);
689 		if (err)
690 			return err;
691 		memmove(&repo->packs[1], &repo->packs[0],
692 		    sizeof(repo->packs) - sizeof(repo->packs[0]));
693 		i = 0;
694 	}
695 
696 	pack = &repo->packs[i];
697 
698 	pack->path_packfile = strdup(path_packfile);
699 	if (pack->path_packfile == NULL) {
700 		err = got_error_from_errno();
701 		goto done;
702 	}
703 
704 	err = open_packfile(&pack->fd, path_packfile, repo, packidx);
705 	if (err)
706 		goto done;
707 
708 	err = get_packfile_size(&pack->filesize, path_packfile);
709 	if (err)
710 		goto done;
711 
712 #ifndef GOT_PACK_NO_MMAP
713 	pack->map = mmap(NULL, pack->filesize, PROT_READ, MAP_PRIVATE,
714 	    pack->fd, 0);
715 	if (pack->map == MAP_FAILED)
716 		pack->map = NULL; /* fall back to read(2) */
717 #endif
718 done:
719 	if (err) {
720 		if (pack) {
721 			free(pack->path_packfile);
722 			memset(pack, 0, sizeof(*pack));
723 		}
724 	} else if (packp)
725 		*packp = pack;
726 	return err;
727 }
728 
729 struct got_pack *
730 get_cached_pack(const char *path_packfile, struct got_repository *repo)
731 {
732 	struct got_pack *pack = NULL;
733 	int i;
734 
735 	for (i = 0; i < nitems(repo->packs); i++) {
736 		pack = &repo->packs[i];
737 		if (pack->path_packfile == NULL)
738 			break;
739 		if (strcmp(pack->path_packfile, path_packfile) == 0)
740 			return pack;
741 	}
742 
743 	return NULL;
744 }
745 
746 static const struct got_error *
747 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
748     struct got_pack *pack, off_t offset)
749 {
750 	uint8_t t = 0;
751 	uint64_t s = 0;
752 	uint8_t sizeN;
753 	size_t mapoff = 0;
754 	int i = 0;
755 
756 	*len = 0;
757 
758 	if (offset >= pack->filesize)
759 		return got_error(GOT_ERR_PACK_OFFSET);
760 
761 	if (pack->map) {
762 		mapoff = (size_t)offset;
763 	} else {
764 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
765 			return got_error_from_errno();
766 	}
767 
768 	do {
769 		/* We do not support size values which don't fit in 64 bit. */
770 		if (i > 9)
771 			return got_error(GOT_ERR_NO_SPACE);
772 
773 		if (pack->map) {
774 			sizeN = *(pack->map + mapoff);
775 			mapoff += sizeof(sizeN);
776 		} else {
777 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
778 			if (n < 0)
779 				return got_error_from_errno();
780 			if (n != sizeof(sizeN))
781 				return got_error(GOT_ERR_BAD_PACKFILE);
782 		}
783 		*len += sizeof(sizeN);
784 
785 		if (i == 0) {
786 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
787 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
788 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
789 		} else {
790 			size_t shift = 4 + 7 * (i - 1);
791 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
792 		}
793 		i++;
794 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
795 
796 	*type = t;
797 	*size = s;
798 	return NULL;
799 }
800 
801 static const struct got_error *
802 open_plain_object(struct got_object **obj, const char *path_packfile,
803     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
804 {
805 	*obj = calloc(1, sizeof(**obj));
806 	if (*obj == NULL)
807 		return got_error_from_errno();
808 
809 	(*obj)->path_packfile = strdup(path_packfile);
810 	if ((*obj)->path_packfile == NULL) {
811 		const struct got_error *err = got_error_from_errno();
812 		free(*obj);
813 		*obj = NULL;
814 		return err;
815 	}
816 
817 	(*obj)->type = type;
818 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
819 	(*obj)->hdrlen = 0;
820 	(*obj)->size = size;
821 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
822 	(*obj)->pack_offset = offset;
823 
824 	return NULL;
825 }
826 
827 static const struct got_error *
828 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
829     off_t delta_offset)
830 {
831 	int64_t o = 0;
832 	uint8_t offN;
833 	int i = 0;
834 
835 	*len = 0;
836 
837 	do {
838 		/* We do not support offset values which don't fit in 64 bit. */
839 		if (i > 8)
840 			return got_error(GOT_ERR_NO_SPACE);
841 
842 		if (pack->map) {
843 			size_t mapoff;
844 			if (delta_offset >= pack->filesize)
845 				return got_error(GOT_ERR_PACK_OFFSET);
846 			mapoff = (size_t)delta_offset + *len;
847 			offN = *(pack->map + mapoff);
848 		} else {
849 			ssize_t n;
850 			n = read(pack->fd, &offN, sizeof(offN));
851 			if (n < 0)
852 				return got_error_from_errno();
853 			if (n != sizeof(offN))
854 				return got_error(GOT_ERR_BAD_PACKFILE);
855 		}
856 		*len += sizeof(offN);
857 
858 		if (i == 0)
859 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
860 		else {
861 			o++;
862 			o <<= 7;
863 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
864 		}
865 		i++;
866 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
867 
868 	*offset = o;
869 	return NULL;
870 }
871 
872 static const struct got_error *
873 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
874     off_t offset, int tslen)
875 {
876 	const struct got_error *err;
877 	int64_t negoffset;
878 	size_t negofflen;
879 
880 	*len = 0;
881 
882 	err = parse_negative_offset(&negoffset, &negofflen, pack,
883 	    offset + tslen);
884 	if (err)
885 		return err;
886 
887 	/* Compute the base object's offset (must be in the same pack file). */
888 	*base_offset = (offset - negoffset);
889 	if (*base_offset <= 0)
890 		return got_error(GOT_ERR_BAD_PACKFILE);
891 
892 	*len = negofflen;
893 	return NULL;
894 }
895 
896 static const struct got_error *
897 resolve_delta_chain(struct got_delta_chain *, struct got_repository *,
898     struct got_packidx *, struct got_pack *, off_t, size_t, int,
899     size_t, unsigned int);
900 
901 static const struct got_error *
902 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
903     int delta_type, size_t delta_size, size_t delta_data_offset,
904     uint8_t *delta_buf, size_t delta_len)
905 {
906 	struct got_delta *delta;
907 
908 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
909 	    delta_data_offset, delta_buf,
910 	    delta_len);
911 	if (delta == NULL)
912 		return got_error_from_errno();
913 	/* delta is freed in got_object_close() */
914 	deltas->nentries++;
915 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
916 	return NULL;
917 }
918 
919 static const struct got_error *
920 resolve_offset_delta(struct got_delta_chain *deltas,
921     struct got_repository *repo, struct got_packidx *packidx,
922     struct got_pack *pack, off_t delta_offset, size_t tslen,
923     int delta_type, size_t delta_size, unsigned int recursion)
924 
925 {
926 	const struct got_error *err;
927 	off_t base_offset;
928 	uint8_t base_type;
929 	uint64_t base_size;
930 	size_t base_tslen;
931 	off_t delta_data_offset;
932 	uint8_t *delta_buf;
933 	size_t delta_len, consumed;
934 
935 	err = parse_offset_delta(&base_offset, &consumed, pack,
936 	    delta_offset, tslen);
937 	if (err)
938 		return err;
939 
940 	delta_data_offset = delta_offset + tslen + consumed;
941 	if (delta_data_offset >= pack->filesize)
942 		return got_error(GOT_ERR_PACK_OFFSET);
943 
944 	if (pack->map == NULL) {
945 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
946 		if (delta_data_offset == -1)
947 			return got_error_from_errno();
948 	}
949 
950 	if (pack->map) {
951 		size_t mapoff = (size_t)delta_data_offset;
952 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
953 		    mapoff, pack->filesize - mapoff);
954 		if (err)
955 			return err;
956 	} else {
957 
958 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
959 		if (err)
960 			return err;
961 	}
962 
963 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
964 	    delta_data_offset, delta_buf, delta_len);
965 	if (err)
966 		goto done;
967 
968 	/* An offset delta must be in the same packfile. */
969 	if (base_offset >= pack->filesize) {
970 		err = got_error(GOT_ERR_PACK_OFFSET);
971 		goto done;
972 	}
973 
974 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
975 	    pack, base_offset);
976 	if (err)
977 		goto done;
978 
979 	err = resolve_delta_chain(deltas, repo, packidx, pack, base_offset,
980 	    base_tslen, base_type, base_size, recursion - 1);
981 done:
982 	if (err)
983 		free(delta_buf);
984 	return err;
985 }
986 
987 static const struct got_error *
988 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
989     struct got_packidx *packidx, struct got_pack *pack,
990     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
991     unsigned int recursion)
992 {
993 	const struct got_error *err;
994 	struct got_object_id id;
995 	int idx;
996 	off_t base_offset;
997 	uint8_t base_type;
998 	uint64_t base_size;
999 	size_t base_tslen;
1000 	off_t delta_data_offset;
1001 	uint8_t *delta_buf = NULL;
1002 	size_t delta_len;
1003 
1004 	if (delta_offset >= pack->filesize)
1005 		return got_error(GOT_ERR_PACK_OFFSET);
1006 	delta_data_offset = delta_offset + tslen;
1007 	if (delta_data_offset >= pack->filesize)
1008 		return got_error(GOT_ERR_PACK_OFFSET);
1009 
1010 	if (pack->map == NULL) {
1011 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1012 		if (delta_data_offset == -1)
1013 			return got_error_from_errno();
1014 	}
1015 
1016 
1017 	if (pack->map) {
1018 		size_t mapoff = (size_t)delta_data_offset;
1019 		memcpy(&id, pack->map + mapoff, sizeof(id));
1020 		mapoff += sizeof(id);
1021 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
1022 		    mapoff, pack->filesize - mapoff);
1023 		if (err)
1024 			goto done;
1025 	} else {
1026 		ssize_t n = read(pack->fd, &id, sizeof(id));
1027 		if (n < 0)
1028 			return got_error_from_errno();
1029 		if (n != sizeof(id))
1030 			return got_error(GOT_ERR_BAD_PACKFILE);
1031 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
1032 		if (err)
1033 			goto done;
1034 	}
1035 
1036 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1037 	    delta_data_offset, delta_buf, delta_len);
1038 	if (err)
1039 		goto done;
1040 
1041 	/* Delta base must be in the same pack file. */
1042 	idx = get_object_idx(packidx, &id);
1043 	if (idx == -1) {
1044 		err = got_error(GOT_ERR_BAD_PACKFILE);
1045 		goto done;
1046 	}
1047 
1048 	base_offset = get_object_offset(packidx, idx);
1049 	if (base_offset == (uint64_t)-1) {
1050 		err = got_error(GOT_ERR_BAD_PACKIDX);
1051 		goto done;
1052 	}
1053 
1054 	if (base_offset >= pack->filesize) {
1055 		err = got_error(GOT_ERR_PACK_OFFSET);
1056 		goto done;
1057 	}
1058 
1059 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
1060 	    pack, base_offset);
1061 	if (err)
1062 		goto done;
1063 
1064 	err = resolve_delta_chain(deltas, repo, packidx, pack, base_offset,
1065 	    base_tslen, base_type, base_size, recursion - 1);
1066 done:
1067 	if (err)
1068 		free(delta_buf);
1069 	return err;
1070 }
1071 
1072 static const struct got_error *
1073 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
1074     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1075     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1076 {
1077 	const struct got_error *err = NULL;
1078 
1079 	if (--recursion == 0)
1080 		return got_error(GOT_ERR_RECURSION);
1081 
1082 	switch (delta_type) {
1083 	case GOT_OBJ_TYPE_COMMIT:
1084 	case GOT_OBJ_TYPE_TREE:
1085 	case GOT_OBJ_TYPE_BLOB:
1086 	case GOT_OBJ_TYPE_TAG:
1087 		/* Plain types are the final delta base. Recursion ends. */
1088 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1089 		    delta_size, 0, NULL, 0);
1090 		break;
1091 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1092 		err = resolve_offset_delta(deltas, repo, packidx, pack,
1093 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1094 		break;
1095 	case GOT_OBJ_TYPE_REF_DELTA:
1096 		err = resolve_ref_delta(deltas, repo, packidx, pack,
1097 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1098 		break;
1099 	default:
1100 		return got_error(GOT_ERR_OBJ_TYPE);
1101 	}
1102 
1103 	return err;
1104 }
1105 
1106 static const struct got_error *
1107 open_delta_object(struct got_object **obj, struct got_repository *repo,
1108     struct got_packidx *packidx, struct got_pack *pack,
1109     struct got_object_id *id, off_t offset, size_t tslen,
1110     int delta_type, size_t delta_size)
1111 {
1112 	const struct got_error *err = NULL;
1113 	int resolved_type;
1114 
1115 	*obj = calloc(1, sizeof(**obj));
1116 	if (*obj == NULL)
1117 		return got_error_from_errno();
1118 
1119 	(*obj)->flags = 0;
1120 	(*obj)->hdrlen = 0;
1121 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1122 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1123 	(*obj)->pack_offset = offset + tslen;
1124 
1125 	(*obj)->path_packfile = strdup(pack->path_packfile);
1126 	if ((*obj)->path_packfile == NULL) {
1127 		err = got_error_from_errno();
1128 		goto done;
1129 	}
1130 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1131 
1132 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
1133 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1134 
1135 	err = resolve_delta_chain(&(*obj)->deltas, repo, packidx, pack, offset,
1136 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
1137 	if (err)
1138 		goto done;
1139 
1140 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1141 	if (err)
1142 		goto done;
1143 	(*obj)->type = resolved_type;
1144 
1145 done:
1146 	if (err) {
1147 		got_object_close(*obj);
1148 		*obj = NULL;
1149 	}
1150 	return err;
1151 }
1152 
1153 static const struct got_error *
1154 open_packed_object(struct got_object **obj, struct got_repository *repo,
1155     struct got_packidx *packidx, int idx, struct got_object_id *id)
1156 {
1157 	const struct got_error *err = NULL;
1158 	off_t offset;
1159 	char *path_packfile;
1160 	struct got_pack *pack;
1161 	uint8_t type;
1162 	uint64_t size;
1163 	size_t tslen;
1164 
1165 	*obj = NULL;
1166 
1167 	offset = get_object_offset(packidx, idx);
1168 	if (offset == (uint64_t)-1)
1169 		return got_error(GOT_ERR_BAD_PACKIDX);
1170 
1171 	err = get_packfile_path(&path_packfile, packidx);
1172 	if (err)
1173 		return err;
1174 
1175 	pack = get_cached_pack(path_packfile, repo);
1176 	if (pack == NULL) {
1177 		err = cache_pack(&pack, path_packfile, packidx, repo);
1178 		if (err)
1179 			goto done;
1180 	}
1181 
1182 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
1183 	if (err)
1184 		goto done;
1185 
1186 	switch (type) {
1187 	case GOT_OBJ_TYPE_COMMIT:
1188 	case GOT_OBJ_TYPE_TREE:
1189 	case GOT_OBJ_TYPE_BLOB:
1190 	case GOT_OBJ_TYPE_TAG:
1191 		err = open_plain_object(obj, path_packfile, id, type,
1192 		    offset + tslen, size);
1193 		break;
1194 
1195 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1196 	case GOT_OBJ_TYPE_REF_DELTA:
1197 		err = open_delta_object(obj, repo, packidx, pack, id, offset,
1198 		    tslen, type, size);
1199 		break;
1200 
1201 	default:
1202 		err = got_error(GOT_ERR_OBJ_TYPE);
1203 		goto done;
1204 	}
1205 done:
1206 	free(path_packfile);
1207 	return err;
1208 }
1209 
1210 const struct got_error *
1211 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
1212     struct got_repository *repo)
1213 {
1214 	const struct got_error *err = NULL;
1215 	struct got_packidx *packidx = NULL;
1216 	int idx;
1217 
1218 	err = search_packidx(&packidx, &idx, repo, id);
1219 	if (err)
1220 		return err;
1221 
1222 	err = open_packed_object(obj, repo, packidx, idx, id);
1223 	if (err)
1224 		return err;
1225 
1226 	err = cache_pack(NULL, (*obj)->path_packfile, packidx, repo);
1227 	return err;
1228 }
1229 
1230 static const struct got_error *
1231 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
1232 {
1233 	struct got_delta *delta;
1234 	uint64_t base_size = 0, result_size = 0;
1235 
1236 	*max_size = 0;
1237 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1238 		/* Plain object types are the delta base. */
1239 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1240 		    delta->type != GOT_OBJ_TYPE_TREE &&
1241 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1242 		    delta->type != GOT_OBJ_TYPE_TAG) {
1243 			const struct got_error *err;
1244 			err = got_delta_get_sizes(&base_size, &result_size,
1245 			    delta->delta_buf, delta->delta_len);
1246 			if (err)
1247 				return err;
1248 		} else
1249 			base_size = delta->size;
1250 		if (base_size > *max_size)
1251 			*max_size = base_size;
1252 		if (result_size > *max_size)
1253 			*max_size = result_size;
1254 	}
1255 
1256 	return NULL;
1257 }
1258 
1259 static const struct got_error *
1260 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
1261     const char *path_packfile, FILE *outfile, struct got_repository *repo)
1262 {
1263 	const struct got_error *err = NULL;
1264 	struct got_delta *delta;
1265 	FILE *base_file = NULL, *accum_file = NULL;
1266 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1267 	size_t accum_size = 0;
1268 	uint64_t max_size;
1269 	int n = 0;
1270 
1271 	*result_size = 0;
1272 
1273 	if (SIMPLEQ_EMPTY(&deltas->entries))
1274 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1275 
1276 	/* We process small enough files entirely in memory for speed. */
1277 	err = get_delta_chain_max_size(&max_size, deltas);
1278 	if (err)
1279 		return err;
1280 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1281 		accum_buf = malloc(max_size);
1282 		if (accum_buf == NULL)
1283 			return got_error_from_errno();
1284 	} else {
1285 		base_file = got_opentemp();
1286 		if (base_file == NULL)
1287 			return got_error_from_errno();
1288 
1289 		accum_file = got_opentemp();
1290 		if (accum_file == NULL) {
1291 			err = got_error_from_errno();
1292 			fclose(base_file);
1293 			return err;
1294 		}
1295 	}
1296 
1297 	/* Deltas are ordered in ascending order. */
1298 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1299 		if (n == 0) {
1300 			struct got_pack *pack;
1301 			size_t base_len, mapoff;
1302 			off_t delta_data_offset;
1303 
1304 			/* Plain object types are the delta base. */
1305 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1306 			    delta->type != GOT_OBJ_TYPE_TREE &&
1307 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1308 			    delta->type != GOT_OBJ_TYPE_TAG) {
1309 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1310 				goto done;
1311 			}
1312 
1313 			pack = get_cached_pack(path_packfile, repo);
1314 			if (pack == NULL) {
1315 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1316 				goto done;
1317 			}
1318 
1319 			delta_data_offset = delta->offset + delta->tslen;
1320 			if (delta_data_offset >= pack->filesize) {
1321 				err = got_error(GOT_ERR_PACK_OFFSET);
1322 				goto done;
1323 			}
1324 			if (pack->map == NULL) {
1325 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1326 				    == -1) {
1327 					err = got_error_from_errno();
1328 					goto done;
1329 				}
1330 			}
1331 			if (base_file) {
1332 				if (pack->map) {
1333 					mapoff = (size_t)delta_data_offset;
1334 					err = got_inflate_to_file_mmap(
1335 					    &base_len, pack->map, mapoff,
1336 					    pack->filesize - mapoff, base_file);
1337 				} else
1338 					err = got_inflate_to_file_fd(&base_len,
1339 					    pack->fd, base_file);
1340 			} else {
1341 				if (pack->map) {
1342 					mapoff = (size_t)delta_data_offset;
1343 					err = got_inflate_to_mem_mmap(&base_buf,
1344 					    &base_len, pack->map, mapoff,
1345 					    pack->filesize - mapoff);
1346 				} else
1347 					err = got_inflate_to_mem_fd(&base_buf,
1348 					    &base_len, pack->fd);
1349 				if (base_len < max_size) {
1350 					uint8_t *p;
1351 					p = reallocarray(base_buf, 1, max_size);
1352 					if (p == NULL) {
1353 						err = got_error_from_errno();
1354 						goto done;
1355 					}
1356 					base_buf = p;
1357 				}
1358 			}
1359 			if (err)
1360 				goto done;
1361 			n++;
1362 			if (base_file)
1363 				rewind(base_file);
1364 			continue;
1365 		}
1366 
1367 		if (base_buf) {
1368 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1369 			    delta->delta_len, accum_buf, &accum_size);
1370 			n++;
1371 		} else {
1372 			err = got_delta_apply(base_file, delta->delta_buf,
1373 			    delta->delta_len,
1374 			    /* Final delta application writes to output file. */
1375 			    ++n < deltas->nentries ? accum_file : outfile,
1376 			    &accum_size);
1377 		}
1378 		if (err)
1379 			goto done;
1380 
1381 		if (n < deltas->nentries) {
1382 			/* Accumulated delta becomes the new base. */
1383 			if (base_buf) {
1384 				uint8_t *tmp = accum_buf;
1385 				accum_buf = base_buf;
1386 				base_buf = tmp;
1387 			} else {
1388 				FILE *tmp = accum_file;
1389 				accum_file = base_file;
1390 				base_file = tmp;
1391 				rewind(base_file);
1392 				rewind(accum_file);
1393 			}
1394 		}
1395 	}
1396 
1397 done:
1398 	free(base_buf);
1399 	if (accum_buf) {
1400 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1401 		free(accum_buf);
1402 		if (len != accum_size)
1403 			err = got_ferror(outfile, GOT_ERR_IO);
1404 	}
1405 	if (base_file)
1406 		fclose(base_file);
1407 	if (accum_file)
1408 		fclose(accum_file);
1409 	rewind(outfile);
1410 	if (err == NULL)
1411 		*result_size = accum_size;
1412 	return err;
1413 }
1414 
1415 static const struct got_error *
1416 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1417     struct got_delta_chain *deltas, const char *path_packfile,
1418     struct got_repository *repo)
1419 {
1420 	const struct got_error *err = NULL;
1421 	struct got_delta *delta;
1422 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1423 	size_t accum_size;
1424 	uint64_t max_size;
1425 	int n = 0;
1426 
1427 	*outbuf = NULL;
1428 	*outlen = 0;
1429 
1430 	if (SIMPLEQ_EMPTY(&deltas->entries))
1431 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1432 
1433 	err = get_delta_chain_max_size(&max_size, deltas);
1434 	if (err)
1435 		return err;
1436 	accum_buf = malloc(max_size);
1437 	if (accum_buf == NULL)
1438 		return got_error_from_errno();
1439 
1440 	/* Deltas are ordered in ascending order. */
1441 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1442 		if (n == 0) {
1443 			struct got_pack *pack;
1444 			size_t base_len;
1445 			size_t delta_data_offset;
1446 
1447 			/* Plain object types are the delta base. */
1448 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1449 			    delta->type != GOT_OBJ_TYPE_TREE &&
1450 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1451 			    delta->type != GOT_OBJ_TYPE_TAG) {
1452 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1453 				goto done;
1454 			}
1455 
1456 			pack = get_cached_pack(path_packfile, repo);
1457 			if (pack == NULL) {
1458 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1459 				goto done;
1460 			}
1461 
1462 			delta_data_offset = delta->offset + delta->tslen;
1463 			if (delta_data_offset >= pack->filesize) {
1464 				err = got_error(GOT_ERR_PACK_OFFSET);
1465 				goto done;
1466 			}
1467 			if (pack->map) {
1468 				size_t mapoff = (size_t)delta_data_offset;
1469 				err = got_inflate_to_mem_mmap(&base_buf,
1470 				    &base_len, pack->map, mapoff,
1471 				    pack->filesize - mapoff);
1472 			} else {
1473 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1474 				    == -1) {
1475 					err = got_error_from_errno();
1476 					goto done;
1477 				}
1478 				err = got_inflate_to_mem_fd(&base_buf,
1479 				    &base_len, pack->fd);
1480 			}
1481 			if (err)
1482 				goto done;
1483 			if (base_len < max_size) {
1484 				uint8_t *p;
1485 				p = reallocarray(base_buf, 1, max_size);
1486 				if (p == NULL) {
1487 					err = got_error_from_errno();
1488 					goto done;
1489 				}
1490 				base_buf = p;
1491 			}
1492 			n++;
1493 			continue;
1494 		}
1495 
1496 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1497 		    delta->delta_len, accum_buf, &accum_size);
1498 		n++;
1499 		if (err)
1500 			goto done;
1501 
1502 		if (n < deltas->nentries) {
1503 			/* Accumulated delta becomes the new base. */
1504 			uint8_t *tmp = accum_buf;
1505 			accum_buf = base_buf;
1506 			base_buf = tmp;
1507 		}
1508 	}
1509 
1510 done:
1511 	free(base_buf);
1512 	if (err) {
1513 		free(accum_buf);
1514 		*outbuf = NULL;
1515 		*outlen = 0;
1516 	} else {
1517 		*outbuf = accum_buf;
1518 		*outlen = accum_size;
1519 	}
1520 	return err;
1521 }
1522 
1523 const struct got_error *
1524 got_packfile_extract_object(FILE **f, struct got_object *obj,
1525     struct got_repository *repo)
1526 {
1527 	const struct got_error *err = NULL;
1528 
1529 	*f = NULL;
1530 
1531 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1532 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1533 
1534 	*f = got_opentemp();
1535 	if (*f == NULL) {
1536 		err = got_error_from_errno();
1537 		goto done;
1538 	}
1539 
1540 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1541 		struct got_pack *pack;
1542 
1543 		pack = get_cached_pack(obj->path_packfile, repo);
1544 		if (pack == NULL) {
1545 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1546 			if (err)
1547 				goto done;
1548 		}
1549 
1550 		if (obj->pack_offset >= pack->filesize) {
1551 			err = got_error(GOT_ERR_PACK_OFFSET);
1552 			goto done;
1553 		}
1554 
1555 		if (pack->map) {
1556 			size_t mapoff = (size_t)obj->pack_offset;
1557 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1558 			    mapoff, pack->filesize - mapoff, *f);
1559 		} else {
1560 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1561 				err = got_error_from_errno();
1562 				goto done;
1563 			}
1564 			err = got_inflate_to_file_fd(&obj->size, pack->fd, *f);
1565 		}
1566 	} else
1567 		err = dump_delta_chain_to_file(&obj->size,
1568 		    &obj->deltas, obj->path_packfile, *f, repo);
1569 done:
1570 	if (err && *f) {
1571 		fclose(*f);
1572 		*f = NULL;
1573 	}
1574 	return err;
1575 }
1576 
1577 const struct got_error *
1578 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1579     struct got_object *obj, struct got_repository *repo)
1580 {
1581 	const struct got_error *err = NULL;
1582 
1583 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1584 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1585 
1586 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1587 		struct got_pack *pack;
1588 
1589 		pack = get_cached_pack(obj->path_packfile, repo);
1590 		if (pack == NULL) {
1591 			err = cache_pack(&pack, obj->path_packfile, NULL, repo);
1592 			if (err)
1593 				goto done;
1594 		}
1595 
1596 		if (obj->pack_offset >= pack->filesize) {
1597 			err = got_error(GOT_ERR_PACK_OFFSET);
1598 			goto done;
1599 		}
1600 		if (pack->map) {
1601 			size_t mapoff = (size_t)obj->pack_offset;
1602 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1603 			    mapoff, pack->filesize - mapoff);
1604 		} else {
1605 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1) {
1606 				err = got_error_from_errno();
1607 				goto done;
1608 			}
1609 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1610 		}
1611 	} else
1612 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas,
1613 		    obj->path_packfile, repo);
1614 done:
1615 	return err;
1616 }