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Date:: Sat Mar 10 00:09:31 2018 UTC
Message:: unwrap short line
Actions:: History | Blame | Raw File
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 
21 #include <dirent.h>
22 #include <errno.h>
23 #include <stdio.h>
24 #include <stdint.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <limits.h>
28 #include <sha1.h>
29 #include <endian.h>
30 #include <zlib.h>
31 
32 #include "got_error.h"
33 #include "got_object.h"
34 #include "got_repository.h"
35 
36 #include "got_sha1_priv.h"
37 #include "got_pack_priv.h"
38 #include "got_path_priv.h"
39 #include "got_delta_priv.h"
40 #include "got_zb_priv.h"
41 #include "got_object_priv.h"
42 #include "got_repository_priv.h"
43 
44 #ifndef nitems
45 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
46 #endif
47 
48 #define GOT_PACK_PREFIX		"pack-"
49 #define GOT_PACKFILE_SUFFIX	".pack"
50 #define GOT_PACKIDX_SUFFIX		".idx"
51 #define GOT_PACKFILE_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
52 				SHA1_DIGEST_STRING_LENGTH - 1 + \
53 				strlen(GOT_PACKFILE_SUFFIX))
54 #define GOT_PACKIDX_NAMELEN	(strlen(GOT_PACK_PREFIX) + \
55 				SHA1_DIGEST_STRING_LENGTH - 1 + \
56 				strlen(GOT_PACKIDX_SUFFIX))
57 
58 #ifndef MIN
59 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
60 #endif
61 
62 static const struct got_error *
63 verify_fanout_table(uint32_t *fanout_table)
64 {
65 	int i;
66 
67 	for (i = 0; i < 0xff - 1; i++) {
68 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
69 			return got_error(GOT_ERR_BAD_PACKIDX);
70 	}
71 
72 	return NULL;
73 }
74 
75 static const struct got_error *
76 get_packfile_size(size_t *size, const char *path_idx)
77 {
78 	struct stat sb;
79 	char *path_pack;
80 	char base_path[PATH_MAX];
81 	char *dot;
82 
83 	if (strlcpy(base_path, path_idx, PATH_MAX) > PATH_MAX)
84 		return got_error(GOT_ERR_NO_SPACE);
85 
86 	dot = strrchr(base_path, '.');
87 	if (dot == NULL)
88 		return got_error(GOT_ERR_BAD_PATH);
89 	*dot = '\0';
90 	if (asprintf(&path_pack, "%s.pack", base_path) == -1)
91 		return got_error(GOT_ERR_NO_MEM);
92 
93 	if (stat(path_pack, &sb) != 0) {
94 		free(path_pack);
95 		return got_error_from_errno();
96 	}
97 
98 	free(path_pack);
99 	*size = sb.st_size;
100 	return 0;
101 }
102 
103 const struct got_error *
104 got_packidx_open(struct got_packidx_v2_hdr **packidx, const char *path)
105 {
106 	struct got_packidx_v2_hdr *p;
107 	FILE *f;
108 	const struct got_error *err = NULL;
109 	size_t n, nobj, packfile_size;
110 	SHA1_CTX ctx;
111 	uint8_t sha1[SHA1_DIGEST_LENGTH];
112 
113 	SHA1Init(&ctx);
114 
115 	f = fopen(path, "rb");
116 	if (f == NULL)
117 		return got_error(GOT_ERR_BAD_PATH);
118 
119 	err = get_packfile_size(&packfile_size, path);
120 	if (err)
121 		return err;
122 
123 	p = calloc(1, sizeof(*p));
124 	if (p == NULL) {
125 		err = got_error(GOT_ERR_NO_MEM);
126 		goto done;
127 	}
128 
129 	n = fread(&p->magic, sizeof(p->magic), 1, f);
130 	if (n != 1) {
131 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
132 		goto done;
133 	}
134 
135 	if (betoh32(p->magic) != GOT_PACKIDX_V2_MAGIC) {
136 		err = got_error(GOT_ERR_BAD_PACKIDX);
137 		goto done;
138 	}
139 
140 	SHA1Update(&ctx, (uint8_t *)&p->magic, sizeof(p->magic));
141 
142 	n = fread(&p->version, sizeof(p->version), 1, f);
143 	if (n != 1) {
144 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
145 		goto done;
146 	}
147 
148 	if (betoh32(p->version) != GOT_PACKIDX_VERSION) {
149 		err = got_error(GOT_ERR_BAD_PACKIDX);
150 		goto done;
151 	}
152 
153 	SHA1Update(&ctx, (uint8_t *)&p->version, sizeof(p->version));
154 
155 	n = fread(&p->fanout_table, sizeof(p->fanout_table), 1, f);
156 	if (n != 1) {
157 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
158 		goto done;
159 	}
160 
161 	err = verify_fanout_table(p->fanout_table);
162 	if (err)
163 		goto done;
164 
165 	SHA1Update(&ctx, (uint8_t *)p->fanout_table, sizeof(p->fanout_table));
166 
167 	nobj = betoh32(p->fanout_table[0xff]);
168 
169 	p->sorted_ids = calloc(nobj, sizeof(*p->sorted_ids));
170 	if (p->sorted_ids == NULL) {
171 		err = got_error(GOT_ERR_NO_MEM);
172 		goto done;
173 	}
174 
175 	n = fread(p->sorted_ids, sizeof(*p->sorted_ids), nobj, f);
176 	if (n != nobj) {
177 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
178 		goto done;
179 	}
180 
181 	SHA1Update(&ctx, (uint8_t *)p->sorted_ids,
182 	    nobj * sizeof(*p->sorted_ids));
183 
184 	p->crc32 = calloc(nobj, sizeof(*p->crc32));
185 	if (p->crc32 == NULL) {
186 		err = got_error(GOT_ERR_NO_MEM);
187 		goto done;
188 	}
189 
190 	n = fread(p->crc32, sizeof(*p->crc32), nobj, f);
191 	if (n != nobj) {
192 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
193 		goto done;
194 	}
195 
196 	SHA1Update(&ctx, (uint8_t *)p->crc32, nobj * sizeof(*p->crc32));
197 
198 	p->offsets = calloc(nobj, sizeof(*p->offsets));
199 	if (p->offsets == NULL) {
200 		err = got_error(GOT_ERR_NO_MEM);
201 		goto done;
202 	}
203 
204 	n = fread(p->offsets, sizeof(*p->offsets), nobj, f);
205 	if (n != nobj) {
206 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
207 		goto done;
208 	}
209 
210 	SHA1Update(&ctx, (uint8_t *)p->offsets, nobj * sizeof(*p->offsets));
211 
212 	/* Large file offsets are contained only in files > 2GB. */
213 	if (packfile_size <= 0x80000000)
214 		goto checksum;
215 
216 	p->large_offsets = calloc(nobj, sizeof(*p->large_offsets));
217 	if (p->large_offsets == NULL) {
218 		err = got_error(GOT_ERR_NO_MEM);
219 		goto done;
220 	}
221 
222 	n = fread(p->large_offsets, sizeof(*p->large_offsets), nobj, f);
223 	if (n != nobj) {
224 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
225 		goto done;
226 	}
227 
228 	SHA1Update(&ctx, (uint8_t*)p->large_offsets,
229 	    nobj * sizeof(*p->large_offsets));
230 
231 checksum:
232 	n = fread(&p->trailer, sizeof(p->trailer), 1, f);
233 	if (n != 1) {
234 		err = got_ferror(f, GOT_ERR_BAD_PACKIDX);
235 		goto done;
236 	}
237 
238 	SHA1Update(&ctx, p->trailer.packfile_sha1, SHA1_DIGEST_LENGTH);
239 	SHA1Final(sha1, &ctx);
240 	if (memcmp(p->trailer.packidx_sha1, sha1, SHA1_DIGEST_LENGTH) != 0)
241 		err = got_error(GOT_ERR_PACKIDX_CSUM);
242 done:
243 	fclose(f);
244 	if (err)
245 		got_packidx_close(p);
246 	else
247 		*packidx = p;
248 	return err;
249 }
250 
251 void
252 got_packidx_close(struct got_packidx_v2_hdr *packidx)
253 {
254 	free(packidx->sorted_ids);
255 	free(packidx->offsets);
256 	free(packidx->crc32);
257 	free(packidx->large_offsets);
258 	free(packidx);
259 }
260 
261 static int
262 is_packidx_filename(const char *name, size_t len)
263 {
264 	if (len != GOT_PACKIDX_NAMELEN)
265 		return 0;
266 
267 	if (strncmp(name, GOT_PACK_PREFIX, strlen(GOT_PACK_PREFIX)) != 0)
268 		return 0;
269 
270 	if (strcmp(name + strlen(GOT_PACK_PREFIX) +
271 	    SHA1_DIGEST_STRING_LENGTH - 1, GOT_PACKIDX_SUFFIX) != 0)
272 		return 0;
273 
274 	return 1;
275 }
276 
277 static off_t
278 get_object_offset(struct got_packidx_v2_hdr *packidx, int idx)
279 {
280 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
281 	uint32_t offset = betoh32(packidx->offsets[idx]);
282 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
283 		uint64_t loffset;
284 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
285 		if (idx < 0 || idx > totobj || packidx->large_offsets == NULL)
286 			return -1;
287 		loffset = betoh64(packidx->large_offsets[idx]);
288 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
289 	}
290 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
291 }
292 
293 static int
294 get_object_idx(struct got_packidx_v2_hdr *packidx, struct got_object_id *id)
295 {
296 	u_int8_t id0 = id->sha1[0];
297 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
298 	int i = 0;
299 
300 	if (id0 > 0)
301 		i = betoh32(packidx->fanout_table[id0 - 1]);
302 
303 	while (i < totobj) {
304 		struct got_object_id *oid = &packidx->sorted_ids[i];
305 		uint32_t offset;
306 		int cmp = got_object_id_cmp(id, oid);
307 
308 		if (cmp == 0)
309 			return i;
310 		i++;
311 	}
312 
313 	return -1;
314 }
315 
316 static struct got_packidx_v2_hdr *
317 dup_packidx(struct got_packidx_v2_hdr *packidx)
318 {
319 	struct got_packidx_v2_hdr *p;
320 	size_t nobj;
321 
322 	p = calloc(1, sizeof(*p));
323 	if (p == NULL)
324 		return NULL;
325 
326 	memcpy(p, packidx, sizeof(*p));
327 	p->sorted_ids = NULL;
328 	p->crc32 = NULL;
329 	p->offsets = NULL;
330 	p->large_offsets = NULL;
331 
332 	nobj = betoh32(p->fanout_table[0xff]);
333 
334 	p->sorted_ids = calloc(nobj, sizeof(*p->sorted_ids));
335 	if (p->sorted_ids == NULL)
336 		goto err;
337 	memcpy(p->sorted_ids, packidx->sorted_ids, nobj * sizeof(*p->sorted_ids));
338 
339 	p->crc32 = calloc(nobj, sizeof(*p->crc32));
340 	if (p->crc32 == NULL)
341 		goto err;
342 	memcpy(p->crc32, packidx->crc32, nobj * sizeof(*p->crc32));
343 
344 	p->offsets = calloc(nobj, sizeof(*p->offsets));
345 	if (p->offsets == NULL)
346 		goto err;
347 	memcpy(p->offsets, packidx->offsets, nobj * sizeof(*p->offsets));
348 
349 	if (p->large_offsets) {
350 		p->large_offsets = calloc(nobj, sizeof(*p->large_offsets));
351 		if (p->large_offsets == NULL)
352 			goto err;
353 		memcpy(p->large_offsets, packidx->large_offsets,
354 		    nobj * sizeof(*p->large_offsets));
355 	}
356 
357 	return p;
358 
359 err:
360 	free(p->large_offsets);
361 	free(p->offsets);
362 	free(p->crc32);
363 	free(p->sorted_ids);
364 	free(p);
365 	return NULL;
366 }
367 
368 static void
369 cache_packidx(struct got_packidx_v2_hdr *packidx, struct got_repository *repo)
370 {
371 	struct got_packidx_v2_hdr *p;
372 	int i;
373 
374 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
375 		if (repo->packidx_cache[i] == NULL)
376 			break;
377 	}
378 
379 	if (i == nitems(repo->packidx_cache)) {
380 		got_packidx_close(repo->packidx_cache[i - 1]);
381 		memmove(&repo->packidx_cache[1], &repo->packidx_cache[0],
382 		    sizeof(repo->packidx_cache) -
383 		    sizeof(repo->packidx_cache[0]));
384 		i = 0;
385 	}
386 
387 	repo->packidx_cache[i] = dup_packidx(packidx);
388 }
389 
390 static const struct got_error *
391 search_packidx(struct got_packidx_v2_hdr **packidx, int *idx,
392     struct got_repository *repo, struct got_object_id *id)
393 {
394 	const struct got_error *err;
395 	char *path_packdir;
396 	DIR *packdir;
397 	struct dirent *dent;
398 	char *path_packidx;
399 	int i;
400 
401 	/* Search pack index cache. */
402 	for (i = 0; i < nitems(repo->packidx_cache); i++) {
403 		if (repo->packidx_cache[i] == NULL)
404 			break;
405 		*idx = get_object_idx(repo->packidx_cache[i], id);
406 		if (*idx != -1) {
407 			*packidx = dup_packidx(repo->packidx_cache[i]);
408 			if (*packidx == NULL)
409 				return got_error(GOT_ERR_NO_MEM);
410 			return NULL;
411 		}
412 	}
413 	/* No luck. Search the filesystem. */
414 
415 	path_packdir = got_repo_get_path_objects_pack(repo);
416 	if (path_packdir == NULL)
417 		return got_error(GOT_ERR_NO_MEM);
418 
419 	packdir = opendir(path_packdir);
420 	if (packdir == NULL) {
421 		err = got_error_from_errno();
422 		goto done;
423 	}
424 
425 	while ((dent = readdir(packdir)) != NULL) {
426 		if (!is_packidx_filename(dent->d_name, dent->d_namlen))
427 			continue;
428 
429 		if (asprintf(&path_packidx, "%s/%s", path_packdir,
430 		    dent->d_name) == -1) {
431 			err = got_error(GOT_ERR_NO_MEM);
432 			goto done;
433 		}
434 
435 		err = got_packidx_open(packidx, path_packidx);
436 		free(path_packidx);
437 		if (err)
438 			goto done;
439 
440 		*idx = get_object_idx(*packidx, id);
441 		if (*idx != -1) {
442 			err = NULL; /* found the object */
443 			cache_packidx(*packidx, repo);
444 			goto done;
445 		}
446 
447 		got_packidx_close(*packidx);
448 		*packidx = NULL;
449 	}
450 
451 	err = got_error(GOT_ERR_NO_OBJ);
452 done:
453 	free(path_packdir);
454 	if (packdir && closedir(packdir) != 0 && err == 0)
455 		err = got_error_from_errno();
456 	return err;
457 }
458 
459 static const struct got_error *
460 get_packfile_path(char **path_packfile, struct got_repository *repo,
461     struct got_packidx_v2_hdr *packidx)
462 {
463 	char *path_packdir;
464 	char hex[SHA1_DIGEST_STRING_LENGTH];
465 	char *sha1str;
466 	char *path_packidx;
467 
468 	*path_packfile = NULL;
469 
470 	path_packdir = got_repo_get_path_objects_pack(repo);
471 	if (path_packdir == NULL)
472 		return got_error(GOT_ERR_NO_MEM);
473 
474 	sha1str = got_sha1_digest_to_str(packidx->trailer.packfile_sha1,
475 	    hex, sizeof(hex));
476 	if (sha1str == NULL)
477 		return got_error(GOT_ERR_PACKIDX_CSUM);
478 
479 	if (asprintf(path_packfile, "%s/%s%s%s", path_packdir,
480 	    GOT_PACK_PREFIX, sha1str, GOT_PACKFILE_SUFFIX) == -1) {
481 		*path_packfile = NULL;
482 		return got_error(GOT_ERR_NO_MEM);
483 	}
484 
485 	return NULL;
486 }
487 
488 const struct got_error *
489 read_packfile_hdr(FILE *f, struct got_packidx_v2_hdr *packidx)
490 {
491 	const struct got_error *err = NULL;
492 	uint32_t totobj = betoh32(packidx->fanout_table[0xff]);
493 	struct got_packfile_hdr hdr;
494 	size_t n;
495 
496 	n = fread(&hdr, sizeof(hdr), 1, f);
497 	if (n != 1)
498 		return got_ferror(f, GOT_ERR_BAD_PACKIDX);
499 
500 	if (betoh32(hdr.signature) != GOT_PACKFILE_SIGNATURE ||
501 	    betoh32(hdr.version) != GOT_PACKFILE_VERSION ||
502 	    betoh32(hdr.nobjects) != totobj)
503 		err = got_error(GOT_ERR_BAD_PACKFILE);
504 
505 	return err;
506 }
507 
508 static const struct got_error *
509 open_packfile(FILE **packfile, char **path_packfile,
510     struct got_repository *repo, struct got_packidx_v2_hdr *packidx)
511 {
512 	const struct got_error *err;
513 
514 	*packfile = NULL;
515 
516 	err = get_packfile_path(path_packfile, repo, packidx);
517 	if (err)
518 		return err;
519 
520 	*packfile = fopen(*path_packfile, "rb");
521 	if (*packfile == NULL) {
522 		err = got_error_from_errno();
523 		free(*path_packfile);
524 		return err;
525 	}
526 
527 	err = read_packfile_hdr(*packfile, packidx);
528 	if (err) {
529 		fclose(*packfile);
530 		*packfile = NULL;
531 	}
532 	return err;
533 }
534 
535 static const struct got_error *
536 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
537     FILE *packfile)
538 {
539 	uint8_t t = 0;
540 	uint64_t s = 0;
541 	uint8_t sizeN;
542 	size_t n;
543 	int i = 0;
544 
545 	do {
546 		/* We do not support size values which don't fit in 64 bit. */
547 		if (i > 9)
548 			return got_error(GOT_ERR_NO_SPACE);
549 
550 		n = fread(&sizeN, sizeof(sizeN), 1, packfile);
551 		if (n != 1)
552 			return got_ferror(packfile, GOT_ERR_BAD_PACKIDX);
553 
554 		if (i == 0) {
555 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
556 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
557 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
558 		} else {
559 			size_t shift = 4 + 7 * (i - 1);
560 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
561 		}
562 		i++;
563 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
564 
565 	*type = t;
566 	*size = s;
567 	*len = i * sizeof(sizeN);
568 	return NULL;
569 }
570 
571 static const struct got_error *
572 open_plain_object(struct got_object **obj, const char *path_packfile,
573     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
574 {
575 	*obj = calloc(1, sizeof(**obj));
576 	if (*obj == NULL)
577 		return got_error(GOT_ERR_NO_MEM);
578 
579 	(*obj)->path_packfile = strdup(path_packfile);
580 	if ((*obj)->path_packfile == NULL) {
581 		free(*obj);
582 		*obj = NULL;
583 		return got_error(GOT_ERR_NO_MEM);
584 	}
585 
586 	(*obj)->type = type;
587 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
588 	(*obj)->hdrlen = 0;
589 	(*obj)->size = size;
590 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
591 	(*obj)->pack_offset = offset;
592 
593 	return NULL;
594 }
595 
596 static const struct got_error *
597 parse_negative_offset(int64_t *offset, size_t *len, FILE *packfile)
598 {
599 	int64_t o = 0;
600 	uint8_t offN;
601 	size_t n;
602 	int i = 0;
603 
604 	do {
605 		/* We do not support offset values which don't fit in 64 bit. */
606 		if (i > 8)
607 			return got_error(GOT_ERR_NO_SPACE);
608 
609 		n = fread(&offN, sizeof(offN), 1, packfile);
610 		if (n != 1)
611 			return got_ferror(packfile, GOT_ERR_BAD_PACKIDX);
612 
613 		if (i == 0)
614 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
615 		else {
616 			o++;
617 			o <<= 7;
618 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
619 		}
620 		i++;
621 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
622 
623 	*offset = o;
624 	*len = i * sizeof(offN);
625 	return NULL;
626 }
627 
628 static const struct got_error *
629 parse_offset_delta(off_t *base_offset, FILE *packfile, off_t offset)
630 {
631 	const struct got_error *err;
632 	int64_t negoffset;
633 	size_t negofflen;
634 
635 	err = parse_negative_offset(&negoffset, &negofflen, packfile);
636 	if (err)
637 		return err;
638 
639 	/* Compute the base object's offset (must be in the same pack file). */
640 	*base_offset = (offset - negoffset);
641 	if (*base_offset <= 0)
642 		return got_error(GOT_ERR_BAD_PACKFILE);
643 
644 	return NULL;
645 }
646 
647 static const struct got_error *
648 resolve_delta_chain(struct got_delta_chain *, struct got_repository *,
649     FILE *, const char *, off_t, size_t, int, size_t);
650 
651 static const struct got_error *
652 add_delta(struct got_delta_chain *deltas, const char *path_packfile,
653     off_t delta_offset, size_t tslen, int delta_type, size_t delta_size,
654     size_t delta_data_offset)
655 {
656 	struct got_delta *delta;
657 
658 	delta = got_delta_open(path_packfile, delta_offset, tslen,
659 	    delta_type, delta_size, delta_data_offset);
660 	if (delta == NULL)
661 		return got_error(GOT_ERR_NO_MEM);
662 	/* delta is freed in got_object_close() */
663 	deltas->nentries++;
664 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
665 	return NULL;
666 }
667 
668 static const struct got_error *
669 resolve_offset_delta(struct got_delta_chain *deltas,
670     struct got_repository *repo, FILE *packfile, const char *path_packfile,
671     off_t delta_offset,size_t tslen, int delta_type, size_t delta_size)
672 
673 {
674 	const struct got_error *err;
675 	off_t base_offset;
676 	uint8_t base_type;
677 	uint64_t base_size;
678 	size_t base_tslen;
679 	off_t delta_data_offset;
680 
681 	err = parse_offset_delta(&base_offset, packfile, delta_offset);
682 	if (err)
683 		return err;
684 
685 	delta_data_offset = ftello(packfile);
686 	if (delta_data_offset == -1)
687 		return got_error_from_errno();
688 
689 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
690 	    delta_type, delta_size, delta_data_offset);
691 	if (err)
692 		return err;
693 
694 	/* An offset delta must be in the same packfile. */
695 	if (fseeko(packfile, base_offset, SEEK_SET) != 0)
696 		return got_error_from_errno();
697 
698 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
699 	    packfile);
700 	if (err)
701 		return err;
702 
703 	return resolve_delta_chain(deltas, repo, packfile, path_packfile,
704 	    base_offset, base_tslen, base_type, base_size);
705 }
706 
707 static const struct got_error *
708 resolve_ref_delta(struct got_delta_chain *deltas, struct got_repository *repo,
709     FILE *packfile, const char *path_packfile, off_t delta_offset,
710     size_t tslen, int delta_type, size_t delta_size)
711 {
712 	const struct got_error *err;
713 	struct got_object_id id;
714 	struct got_packidx_v2_hdr *packidx;
715 	int idx;
716 	off_t base_offset;
717 	uint8_t base_type;
718 	uint64_t base_size;
719 	size_t base_tslen;
720 	size_t n;
721 	FILE *base_packfile;
722 	char *path_base_packfile;
723 	off_t delta_data_offset;
724 
725 	n = fread(&id, sizeof(id), 1, packfile);
726 	if (n != 1)
727 		return got_ferror(packfile, GOT_ERR_IO);
728 
729 	delta_data_offset = ftello(packfile);
730 	if (delta_data_offset == -1)
731 		return got_error_from_errno();
732 
733 	err = add_delta(deltas, path_packfile, delta_offset, tslen,
734 	    delta_type, delta_size, delta_data_offset);
735 	if (err)
736 		return err;
737 
738 	err = search_packidx(&packidx, &idx, repo, &id);
739 	if (err)
740 		return err;
741 
742 	base_offset = get_object_offset(packidx, idx);
743 	if (base_offset == (uint64_t)-1) {
744 		got_packidx_close(packidx);
745 		return got_error(GOT_ERR_BAD_PACKIDX);
746 	}
747 
748 	err = open_packfile(&base_packfile, &path_base_packfile, repo, packidx);
749 	got_packidx_close(packidx);
750 	if (err)
751 		return err;
752 
753 	if (fseeko(base_packfile, base_offset, SEEK_SET) != 0) {
754 		err = got_error_from_errno();
755 		goto done;
756 	}
757 
758 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
759 	    base_packfile);
760 	if (err)
761 		goto done;
762 
763 	err = resolve_delta_chain(deltas, repo, base_packfile,
764 	    path_base_packfile, base_offset, base_tslen, base_type,
765 	    base_size);
766 done:
767 	free(path_base_packfile);
768 	if (base_packfile && fclose(base_packfile) == -1 && err == 0)
769 		err = got_error_from_errno();
770 	return err;
771 }
772 
773 static const struct got_error *
774 resolve_delta_chain(struct got_delta_chain *deltas, struct got_repository *repo,
775     FILE *packfile, const char *path_packfile, off_t delta_offset, size_t tslen,
776     int delta_type, size_t delta_size)
777 {
778 	const struct got_error *err = NULL;
779 
780 	switch (delta_type) {
781 	case GOT_OBJ_TYPE_COMMIT:
782 	case GOT_OBJ_TYPE_TREE:
783 	case GOT_OBJ_TYPE_BLOB:
784 	case GOT_OBJ_TYPE_TAG:
785 		/* Plain types are the final delta base. Recursion ends. */
786 		err = add_delta(deltas, path_packfile, delta_offset, tslen,
787 		    delta_type, delta_size, 0);
788 		break;
789 	case GOT_OBJ_TYPE_OFFSET_DELTA:
790 		err = resolve_offset_delta(deltas, repo, packfile,
791 		    path_packfile, delta_offset, tslen, delta_type,
792 		    delta_size);
793 		break;
794 	case GOT_OBJ_TYPE_REF_DELTA:
795 		err = resolve_ref_delta(deltas, repo, packfile,
796 		    path_packfile, delta_offset, tslen, delta_type,
797 		    delta_size);
798 		break;
799 	default:
800 		return got_error(GOT_ERR_NOT_IMPL);
801 	}
802 
803 	return err;
804 }
805 
806 static const struct got_error *
807 open_delta_object(struct got_object **obj, struct got_repository *repo,
808     struct got_packidx_v2_hdr *packidx, const char *path_packfile,
809     FILE *packfile, struct got_object_id *id, off_t offset, size_t tslen,
810     int delta_type, size_t delta_size)
811 {
812 	const struct got_error *err = NULL;
813 	struct got_object_id base_id;
814 	uint8_t base_type;
815 	int resolved_type;
816 	uint64_t base_size;
817 	size_t base_tslen;
818 
819 	*obj = calloc(1, sizeof(**obj));
820 	if (*obj == NULL)
821 		return got_error(GOT_ERR_NO_MEM);
822 
823 	(*obj)->flags = 0;
824 	(*obj)->hdrlen = 0;
825 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
826 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
827 	(*obj)->pack_offset = offset + tslen;
828 
829 	(*obj)->path_packfile = strdup(path_packfile);
830 	if ((*obj)->path_packfile == NULL) {
831 		err = got_error(GOT_ERR_NO_MEM);
832 		goto done;
833 	}
834 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
835 
836 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
837 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
838 
839 	err = resolve_delta_chain(&(*obj)->deltas, repo, packfile,
840 	    path_packfile, offset, tslen, delta_type, delta_size);
841 	if (err)
842 		goto done;
843 
844 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
845 	if (err)
846 		goto done;
847 	(*obj)->type = resolved_type;
848 
849 done:
850 	if (err) {
851 		got_object_close(*obj);
852 		*obj = NULL;
853 	}
854 	return err;
855 }
856 
857 static const struct got_error *
858 open_packed_object(struct got_object **obj, struct got_repository *repo,
859     struct got_packidx_v2_hdr *packidx, int idx, struct got_object_id *id)
860 {
861 	const struct got_error *err = NULL;
862 	off_t offset;
863 	char *path_packfile;
864 	FILE *packfile;
865 	uint8_t type;
866 	uint64_t size;
867 	size_t tslen;
868 
869 	*obj = NULL;
870 
871 	offset = get_object_offset(packidx, idx);
872 	if (offset == (uint64_t)-1)
873 		return got_error(GOT_ERR_BAD_PACKIDX);
874 
875 	err = open_packfile(&packfile, &path_packfile, repo, packidx);
876 	if (err)
877 		return err;
878 
879 	if (fseeko(packfile, offset, SEEK_SET) != 0) {
880 		err = got_error_from_errno();
881 		goto done;
882 	}
883 
884 	err = parse_object_type_and_size(&type, &size, &tslen, packfile);
885 	if (err)
886 		goto done;
887 
888 	switch (type) {
889 	case GOT_OBJ_TYPE_COMMIT:
890 	case GOT_OBJ_TYPE_TREE:
891 	case GOT_OBJ_TYPE_BLOB:
892 	case GOT_OBJ_TYPE_TAG:
893 		err = open_plain_object(obj, path_packfile, id, type,
894 		    offset + tslen, size);
895 		break;
896 
897 	case GOT_OBJ_TYPE_OFFSET_DELTA:
898 	case GOT_OBJ_TYPE_REF_DELTA:
899 		err = open_delta_object(obj, repo, packidx, path_packfile,
900 		    packfile, id, offset, tslen, type, size);
901 		break;
902 
903 	default:
904 		err = got_error(GOT_ERR_NOT_IMPL);
905 		goto done;
906 	}
907 done:
908 	free(path_packfile);
909 	if (packfile && fclose(packfile) == -1 && err == 0)
910 		err = got_error_from_errno();
911 	return err;
912 }
913 
914 const struct got_error *
915 got_packfile_open_object(struct got_object **obj, struct got_object_id *id,
916     struct got_repository *repo)
917 {
918 	const struct got_error *err = NULL;
919 	struct got_packidx_v2_hdr *packidx = NULL;
920 	int idx;
921 
922 	err = search_packidx(&packidx, &idx, repo, id);
923 	if (err)
924 		return err;
925 
926 	err = open_packed_object(obj, repo, packidx, idx, id);
927 	got_packidx_close(packidx);
928 	return err;
929 }
930 
931 static const struct got_error *
932 dump_delta_chain(struct got_delta_chain *deltas, FILE *outfile)
933 {
934 	const struct got_error *err = NULL;
935 	struct got_delta *delta;
936 	FILE *base_file, *accum_file;
937 	int n = 0;
938 
939 	if (SIMPLEQ_EMPTY(&deltas->entries))
940 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
941 
942 	base_file = got_opentemp();
943 	if (base_file == NULL)
944 		return got_error_from_errno();
945 
946 	accum_file = got_opentemp();
947 	if (accum_file == NULL) {
948 		err = got_error_from_errno();
949 		fclose(base_file);
950 		return err;
951 	}
952 
953 	/* Deltas are ordered in ascending order. */
954 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
955 		uint8_t *delta_buf = NULL;
956 		size_t delta_len = 0;
957 		FILE *delta_file;
958 
959 		delta_file = fopen(delta->path_packfile, "rb");
960 		if (delta_file == NULL) {
961 			err = got_error_from_errno();
962 			goto done;
963 		}
964 
965 
966 		if (n == 0) {
967 			/* Plain object types are the delta base. */
968 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
969 			    delta->type != GOT_OBJ_TYPE_TREE &&
970 			    delta->type != GOT_OBJ_TYPE_BLOB &&
971 			    delta->type != GOT_OBJ_TYPE_TAG) {
972 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
973 				goto done;
974 			}
975 
976 			if (fseeko(delta_file, delta->offset + delta->tslen,
977 			    SEEK_SET) != 0) {
978 				fclose(delta_file);
979 				err = got_error_from_errno();
980 				goto done;
981 			}
982 			err = got_inflate_to_file(&delta_len, delta_file,
983 			    base_file);
984 			fclose(delta_file);
985 			if (err)
986 				goto done;
987 			n++;
988 			rewind(base_file);
989 			continue;
990 		}
991 
992 		if (fseeko(delta_file, delta->data_offset, SEEK_CUR) != 0) {
993 			fclose(delta_file);
994 			err = got_error_from_errno();
995 			goto done;
996 		}
997 
998 		/* Delta streams should always fit in memory. */
999 		err = got_inflate_to_mem(&delta_buf, &delta_len, delta_file);
1000 		fclose(delta_file);
1001 		if (err)
1002 			goto done;
1003 
1004 		err = got_delta_apply(base_file, delta_buf, delta_len,
1005 		    /* Final delta application writes to the output file. */
1006 		    ++n < deltas->nentries ? accum_file : outfile);
1007 		free(delta_buf);
1008 		if (err)
1009 			goto done;
1010 
1011 		if (n < deltas->nentries) {
1012 			/* Accumulated delta becomes the new base. */
1013 			FILE *tmp = accum_file;
1014 			accum_file = base_file;
1015 			base_file = tmp;
1016 			rewind(base_file);
1017 			rewind(accum_file);
1018 		}
1019 	}
1020 
1021 done:
1022 	fclose(base_file);
1023 	fclose(accum_file);
1024 	rewind(outfile);
1025 	return err;
1026 }
1027 
1028 const struct got_error *
1029 got_packfile_extract_object(FILE **f, struct got_object *obj,
1030     struct got_repository *repo)
1031 {
1032 	const struct got_error *err = NULL;
1033 	FILE *packfile = NULL;
1034 
1035 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1036 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1037 
1038 	*f = got_opentemp();
1039 	if (*f == NULL) {
1040 		err = got_error(GOT_ERR_FILE_OPEN);
1041 		goto done;
1042 	}
1043 
1044 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1045 		packfile = fopen(obj->path_packfile, "rb");
1046 		if (packfile == NULL) {
1047 			err = got_error_from_errno();
1048 			goto done;
1049 		}
1050 
1051 		if (fseeko(packfile, obj->pack_offset, SEEK_SET) != 0) {
1052 			err = got_error_from_errno();
1053 			goto done;
1054 		}
1055 
1056 		err = got_inflate_to_file(&obj->size, packfile, *f);
1057 	} else
1058 		err = dump_delta_chain(&obj->deltas, *f);
1059 done:
1060 	if (packfile)
1061 		fclose(packfile);
1062 	if (err && *f)
1063 		fclose(*f);
1064 	return err;
1065 }