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Date:: Mon Sep 10 10:30:47 2018 UTC
Message:: start reading pack files with privsep; still WIP
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 #include <sys/uio.h>
21 #include <sys/mman.h>
22 
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <zlib.h>
33 #include <imsg.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_opentemp.h"
38 
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_privsep.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #ifndef MIN
52 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
53 #endif
54 
55 static const struct got_error *
56 verify_fanout_table(uint32_t *fanout_table)
57 {
58 	int i;
59 
60 	for (i = 0; i < 0xff - 1; i++) {
61 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
62 			return got_error(GOT_ERR_BAD_PACKIDX);
63 	}
64 
65 	return NULL;
66 }
67 
68 const struct got_error *
69 got_pack_get_packfile_size(size_t *size, const char *path)
70 {
71 	struct stat sb;
72 	char *dot;
73 
74 	*size = 0;
75 
76 	dot = strrchr(path, '.');
77 	if (dot == NULL)
78 		return got_error(GOT_ERR_BAD_PATH);
79 
80 	/* Path must point to a pack index or to a pack file. */
81 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
82 		const struct got_error *err = NULL;
83 		char *path_pack;
84 		char base_path[PATH_MAX];
85 
86 		/* Convert pack index path to pack file path. */
87 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
88 			return got_error(GOT_ERR_NO_SPACE);
89 		dot = strrchr(base_path, '.');
90 		if (dot == NULL)
91 			return got_error(GOT_ERR_BAD_PATH);
92 		*dot = '\0';
93 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
94 			return got_error_from_errno();
95 
96 		if (stat(path_pack, &sb) != 0)
97 			err = got_error_from_errno();
98 		free(path_pack);
99 		if (err)
100 			return err;
101 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
102 		if (stat(path, &sb) != 0)
103 			return got_error_from_errno();
104 	} else
105 		return got_error(GOT_ERR_BAD_PATH);
106 
107 	*size = sb.st_size;
108 	return 0;
109 }
110 
111 const struct got_error *
112 got_packidx_init_hdr(struct got_packidx *p, int verify)
113 {
114 	const struct got_error *err = NULL;
115 	struct got_packidx_v2_hdr *h;
116 	SHA1_CTX ctx;
117 	uint8_t sha1[SHA1_DIGEST_LENGTH];
118 	size_t nobj, len_fanout, len_ids, offset, remain;
119 	ssize_t n;
120 
121 	SHA1Init(&ctx);
122 
123 	h = &p->hdr;
124 	offset = 0;
125 	remain = p->len;
126 
127 	if (remain < sizeof(*h->magic)) {
128 		err = got_error(GOT_ERR_BAD_PACKIDX);
129 		goto done;
130 	}
131 	if (p->map)
132 		h->magic = (uint32_t *)(p->map + offset);
133 	else {
134 		h->magic = malloc(sizeof(*h->magic));
135 		if (h->magic == NULL) {
136 			err = got_error_from_errno();
137 			goto done;
138 		}
139 		n = read(p->fd, h->magic, sizeof(*h->magic));
140 		if (n != sizeof(*h->magic)) {
141 			err = got_error(GOT_ERR_BAD_PACKIDX);
142 			goto done;
143 		}
144 	}
145 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
146 		err = got_error(GOT_ERR_BAD_PACKIDX);
147 		goto done;
148 	}
149 	offset += sizeof(*h->magic);
150 	remain -= sizeof(*h->magic);
151 
152 	if (verify)
153 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
154 
155 	if (remain < sizeof(*h->version)) {
156 		err = got_error(GOT_ERR_BAD_PACKIDX);
157 		goto done;
158 	}
159 	if (p->map)
160 		h->version = (uint32_t *)(p->map + offset);
161 	else {
162 		h->version = malloc(sizeof(*h->version));
163 		if (h->version == NULL) {
164 			err = got_error_from_errno();
165 			goto done;
166 		}
167 		n = read(p->fd, h->version, sizeof(*h->version));
168 		if (n != sizeof(*h->version)) {
169 			err = got_error(GOT_ERR_BAD_PACKIDX);
170 			goto done;
171 		}
172 	}
173 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
174 		err = got_error(GOT_ERR_BAD_PACKIDX);
175 		goto done;
176 	}
177 	offset += sizeof(*h->version);
178 	remain -= sizeof(*h->version);
179 
180 	if (verify)
181 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
182 
183 	len_fanout =
184 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
185 	if (remain < len_fanout) {
186 		err = got_error(GOT_ERR_BAD_PACKIDX);
187 		goto done;
188 	}
189 	if (p->map)
190 		h->fanout_table = (uint32_t *)(p->map + offset);
191 	else {
192 		h->fanout_table = malloc(len_fanout);
193 		if (h->fanout_table == NULL) {
194 			err = got_error_from_errno();
195 			goto done;
196 		}
197 		n = read(p->fd, h->fanout_table, len_fanout);
198 		if (n != len_fanout) {
199 			err = got_error(GOT_ERR_BAD_PACKIDX);
200 			goto done;
201 		}
202 	}
203 	err = verify_fanout_table(h->fanout_table);
204 	if (err)
205 		goto done;
206 	if (verify)
207 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
208 	offset += len_fanout;
209 	remain -= len_fanout;
210 
211 	nobj = betoh32(h->fanout_table[0xff]);
212 	len_ids = nobj * sizeof(*h->sorted_ids);
213 	if (len_ids <= nobj || len_ids > remain) {
214 		err = got_error(GOT_ERR_BAD_PACKIDX);
215 		goto done;
216 	}
217 	if (p->map)
218 		h->sorted_ids =
219 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
220 	else {
221 		h->sorted_ids = malloc(len_ids);
222 		if (h->sorted_ids == NULL) {
223 			err = got_error(GOT_ERR_BAD_PACKIDX);
224 			goto done;
225 		}
226 		n = read(p->fd, h->sorted_ids, len_ids);
227 		if (n != len_ids) {
228 			err = got_error(GOT_ERR_BAD_PACKIDX);
229 			goto done;
230 		}
231 	}
232 	if (verify)
233 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
234 	offset += len_ids;
235 	remain -= len_ids;
236 
237 	if (remain < nobj * sizeof(*h->crc32)) {
238 		err = got_error(GOT_ERR_BAD_PACKIDX);
239 		goto done;
240 	}
241 	if (p->map)
242 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
243 	else {
244 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
245 		if (h->crc32 == NULL) {
246 			err = got_error_from_errno();
247 			goto done;
248 		}
249 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
250 		if (n != nobj * sizeof(*h->crc32)) {
251 			err = got_error(GOT_ERR_BAD_PACKIDX);
252 			goto done;
253 		}
254 	}
255 	if (verify)
256 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
257 	remain -= nobj * sizeof(*h->crc32);
258 	offset += nobj * sizeof(*h->crc32);
259 
260 	if (remain < nobj * sizeof(*h->offsets)) {
261 		err = got_error(GOT_ERR_BAD_PACKIDX);
262 		goto done;
263 	}
264 	if (p->map)
265 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
266 	else {
267 		h->offsets = malloc(nobj * sizeof(*h->offsets));
268 		if (h->offsets == NULL) {
269 			err = got_error_from_errno();
270 			goto done;
271 		}
272 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
273 		if (n != nobj * sizeof(*h->offsets)) {
274 			err = got_error(GOT_ERR_BAD_PACKIDX);
275 			goto done;
276 		}
277 	}
278 	if (verify)
279 		SHA1Update(&ctx, (uint8_t *)h->offsets,
280 		    nobj * sizeof(*h->offsets));
281 	remain -= nobj * sizeof(*h->offsets);
282 	offset += nobj * sizeof(*h->offsets);
283 
284 	/* Large file offsets are contained only in files > 2GB. */
285 	if (p->len <= 0x80000000)
286 		goto checksum;
287 
288 	if (remain < nobj * sizeof(*h->large_offsets)) {
289 		err = got_error(GOT_ERR_BAD_PACKIDX);
290 		goto done;
291 	}
292 	if (p->map)
293 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
294 	else {
295 		h->offsets = malloc(nobj * sizeof(*h->large_offsets));
296 		if (h->offsets == NULL) {
297 			err = got_error_from_errno();
298 			goto done;
299 		}
300 		n = read(p->fd, h->large_offsets,
301 		    nobj * sizeof(*h->large_offsets));
302 		if (n != nobj * sizeof(*h->large_offsets)) {
303 			err = got_error(GOT_ERR_BAD_PACKIDX);
304 			goto done;
305 		}
306 	}
307 	if (verify)
308 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
309 		    nobj * sizeof(*h->large_offsets));
310 	remain -= nobj * sizeof(*h->large_offsets);
311 	offset += nobj * sizeof(*h->large_offsets);
312 
313 checksum:
314 	if (remain < sizeof(*h->trailer)) {
315 		err = got_error(GOT_ERR_BAD_PACKIDX);
316 		goto done;
317 	}
318 	if (p->map)
319 		h->trailer =
320 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
321 	else {
322 		h->trailer = malloc(sizeof(*h->trailer));
323 		if (h->trailer == NULL) {
324 			err = got_error_from_errno();
325 			goto done;
326 		}
327 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
328 		if (n != sizeof(*h->trailer)) {
329 			err = got_error(GOT_ERR_BAD_PACKIDX);
330 			goto done;
331 		}
332 	}
333 	if (verify) {
334 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
335 		SHA1Final(sha1, &ctx);
336 		if (memcmp(h->trailer->packidx_sha1, sha1,
337 		    SHA1_DIGEST_LENGTH) != 0)
338 			err = got_error(GOT_ERR_PACKIDX_CSUM);
339 	}
340 done:
341 	return err;
342 }
343 
344 const struct got_error *
345 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
346 {
347 	const struct got_error *err = NULL;
348 	struct got_packidx *p;
349 
350 	*packidx = NULL;
351 
352 	p = calloc(1, sizeof(*p));
353 	if (p == NULL)
354 		return got_error_from_errno();
355 
356 	p->fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
357 	if (p->fd == -1)
358 		return got_error_from_errno();
359 
360 	err = got_pack_get_packfile_size(&p->len, path);
361 	if (err) {
362 		close(p->fd);
363 		free(p);
364 		return err;
365 	}
366 	if (p->len < sizeof(p->hdr)) {
367 		err = got_error(GOT_ERR_BAD_PACKIDX);
368 		close(p->fd);
369 		free(p);
370 		return err;
371 	}
372 
373 	p->path_packidx = strdup(path);
374 	if (p->path_packidx == NULL) {
375 		err = got_error_from_errno();
376 		goto done;
377 	}
378 
379 #ifndef GOT_PACK_NO_MMAP
380 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
381 	if (p->map == MAP_FAILED)
382 		p->map = NULL; /* fall back to read(2) */
383 #endif
384 
385 	err = got_packidx_init_hdr(p, verify);
386 done:
387 	if (err)
388 		got_packidx_close(p);
389 	else
390 		*packidx = p;
391 
392 	return err;
393 }
394 
395 const struct got_error *
396 got_packidx_close(struct got_packidx *packidx)
397 {
398 	const struct got_error *err = NULL;
399 
400 	free(packidx->path_packidx);
401 	if (packidx->map) {
402 		if (munmap(packidx->map, packidx->len) == -1)
403 			err = got_error_from_errno();
404 	} else {
405 		free(packidx->hdr.magic);
406 		free(packidx->hdr.version);
407 		free(packidx->hdr.fanout_table);
408 		free(packidx->hdr.sorted_ids);
409 		free(packidx->hdr.crc32);
410 		free(packidx->hdr.offsets);
411 		free(packidx->hdr.large_offsets);
412 		free(packidx->hdr.trailer);
413 	}
414 	close(packidx->fd);
415 	free(packidx);
416 
417 	return err;
418 }
419 
420 static off_t
421 get_object_offset(struct got_packidx *packidx, int idx)
422 {
423 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
424 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
425 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
426 		uint64_t loffset;
427 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
428 		if (idx < 0 || idx > totobj ||
429 		    packidx->hdr.large_offsets == NULL)
430 			return -1;
431 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
432 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
433 	}
434 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
435 }
436 
437 int
438 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
439 {
440 	u_int8_t id0 = id->sha1[0];
441 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
442 	int left = 0, right = totobj - 1;
443 
444 	if (id0 > 0)
445 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
446 
447 	while (left <= right) {
448 		struct got_packidx_object_id *oid;
449 		int i, cmp;
450 
451 		i = ((left + right) / 2);
452 		oid = &packidx->hdr.sorted_ids[i];
453 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
454 		if (cmp == 0)
455 			return i;
456 		else if (cmp > 0)
457 			left = i + 1;
458 		else if (cmp < 0)
459 			right = i - 1;
460 	}
461 
462 	return -1;
463 }
464 
465 const struct got_error *
466 got_pack_stop_privsep_child(struct got_pack *pack)
467 {
468 	const struct got_error *err = NULL, *child_err = NULL;
469 
470 	if (pack->privsep_child == NULL)
471 		return NULL;
472 
473 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
474 	child_err = got_privsep_wait_for_child(
475 	    pack->privsep_child->pid);
476 	if (child_err && err == NULL)
477 		err = child_err;
478 	free(pack->privsep_child);
479 	pack->privsep_child = NULL;
480 	return err;
481 }
482 
483 const struct got_error *
484 got_pack_close(struct got_pack *pack)
485 {
486 	const struct got_error *err = NULL;
487 
488 	err = got_pack_stop_privsep_child(pack);
489 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
490 		err = got_error_from_errno();
491 	close(pack->fd);
492 	pack->fd = -1;
493 	free(pack->path_packfile);
494 	pack->path_packfile = NULL;
495 	pack->filesize = 0;
496 
497 	return err;
498 }
499 
500 static const struct got_error *
501 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
502     struct got_pack *pack, off_t offset)
503 {
504 	uint8_t t = 0;
505 	uint64_t s = 0;
506 	uint8_t sizeN;
507 	size_t mapoff = 0;
508 	int i = 0;
509 
510 	*len = 0;
511 
512 	if (offset >= pack->filesize)
513 		return got_error(GOT_ERR_PACK_OFFSET);
514 
515 	if (pack->map) {
516 		mapoff = (size_t)offset;
517 	} else {
518 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
519 			return got_error_from_errno();
520 	}
521 
522 	do {
523 		/* We do not support size values which don't fit in 64 bit. */
524 		if (i > 9)
525 			return got_error(GOT_ERR_NO_SPACE);
526 
527 		if (pack->map) {
528 			sizeN = *(pack->map + mapoff);
529 			mapoff += sizeof(sizeN);
530 		} else {
531 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
532 			if (n < 0)
533 				return got_error_from_errno();
534 			if (n != sizeof(sizeN))
535 				return got_error(GOT_ERR_BAD_PACKFILE);
536 		}
537 		*len += sizeof(sizeN);
538 
539 		if (i == 0) {
540 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
541 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
542 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
543 		} else {
544 			size_t shift = 4 + 7 * (i - 1);
545 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
546 		}
547 		i++;
548 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
549 
550 	*type = t;
551 	*size = s;
552 	return NULL;
553 }
554 
555 static const struct got_error *
556 open_plain_object(struct got_object **obj, const char *path_packfile,
557     struct got_object_id *id, uint8_t type, off_t offset, size_t size)
558 {
559 	*obj = calloc(1, sizeof(**obj));
560 	if (*obj == NULL)
561 		return got_error_from_errno();
562 
563 	(*obj)->path_packfile = strdup(path_packfile);
564 	if ((*obj)->path_packfile == NULL) {
565 		const struct got_error *err = got_error_from_errno();
566 		free(*obj);
567 		*obj = NULL;
568 		return err;
569 	}
570 
571 	(*obj)->type = type;
572 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
573 	(*obj)->hdrlen = 0;
574 	(*obj)->size = size;
575 	if (id)
576 		memcpy(&(*obj)->id, id, sizeof((*obj)->id));
577 	(*obj)->pack_offset = offset;
578 
579 	return NULL;
580 }
581 
582 static const struct got_error *
583 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
584     off_t delta_offset)
585 {
586 	int64_t o = 0;
587 	uint8_t offN;
588 	int i = 0;
589 
590 	*len = 0;
591 
592 	do {
593 		/* We do not support offset values which don't fit in 64 bit. */
594 		if (i > 8)
595 			return got_error(GOT_ERR_NO_SPACE);
596 
597 		if (pack->map) {
598 			size_t mapoff;
599 			if (delta_offset >= pack->filesize)
600 				return got_error(GOT_ERR_PACK_OFFSET);
601 			mapoff = (size_t)delta_offset + *len;
602 			offN = *(pack->map + mapoff);
603 		} else {
604 			ssize_t n;
605 			n = read(pack->fd, &offN, sizeof(offN));
606 			if (n < 0)
607 				return got_error_from_errno();
608 			if (n != sizeof(offN))
609 				return got_error(GOT_ERR_BAD_PACKFILE);
610 		}
611 		*len += sizeof(offN);
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 	return NULL;
625 }
626 
627 static const struct got_error *
628 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
629     off_t offset, int tslen)
630 {
631 	const struct got_error *err;
632 	int64_t negoffset;
633 	size_t negofflen;
634 
635 	*len = 0;
636 
637 	err = parse_negative_offset(&negoffset, &negofflen, pack,
638 	    offset + tslen);
639 	if (err)
640 		return err;
641 
642 	/* Compute the base object's offset (must be in the same pack file). */
643 	*base_offset = (offset - negoffset);
644 	if (*base_offset <= 0)
645 		return got_error(GOT_ERR_BAD_PACKFILE);
646 
647 	*len = negofflen;
648 	return NULL;
649 }
650 
651 static const struct got_error *
652 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
653     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
654 
655 static const struct got_error *
656 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
657     int delta_type, size_t delta_size, size_t delta_data_offset,
658     uint8_t *delta_buf, size_t delta_len)
659 {
660 	struct got_delta *delta;
661 
662 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
663 	    delta_data_offset, delta_buf,
664 	    delta_len);
665 	if (delta == NULL)
666 		return got_error_from_errno();
667 	/* delta is freed in got_object_close() */
668 	deltas->nentries++;
669 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
670 	return NULL;
671 }
672 
673 static const struct got_error *
674 resolve_offset_delta(struct got_delta_chain *deltas,
675     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
676     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
677 
678 {
679 	const struct got_error *err;
680 	off_t base_offset;
681 	uint8_t base_type;
682 	uint64_t base_size;
683 	size_t base_tslen;
684 	off_t delta_data_offset;
685 	uint8_t *delta_buf;
686 	size_t delta_len, consumed;
687 
688 	err = parse_offset_delta(&base_offset, &consumed, pack,
689 	    delta_offset, tslen);
690 	if (err)
691 		return err;
692 
693 	delta_data_offset = delta_offset + tslen + consumed;
694 	if (delta_data_offset >= pack->filesize)
695 		return got_error(GOT_ERR_PACK_OFFSET);
696 
697 	if (pack->map == NULL) {
698 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
699 		if (delta_data_offset == -1)
700 			return got_error_from_errno();
701 	}
702 
703 	if (pack->map) {
704 		size_t mapoff = (size_t)delta_data_offset;
705 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
706 		    mapoff, pack->filesize - mapoff);
707 		if (err)
708 			return err;
709 	} else {
710 
711 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
712 		if (err)
713 			return err;
714 	}
715 
716 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
717 	    delta_data_offset, delta_buf, delta_len);
718 	if (err)
719 		goto done;
720 
721 	/* An offset delta must be in the same packfile. */
722 	if (base_offset >= pack->filesize) {
723 		err = got_error(GOT_ERR_PACK_OFFSET);
724 		goto done;
725 	}
726 
727 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
728 	    pack, base_offset);
729 	if (err)
730 		goto done;
731 
732 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
733 	    base_tslen, base_type, base_size, recursion - 1);
734 done:
735 	if (err)
736 		free(delta_buf);
737 	return err;
738 }
739 
740 static const struct got_error *
741 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
742     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
743     size_t delta_size, unsigned int recursion)
744 {
745 	const struct got_error *err;
746 	struct got_object_id id;
747 	int idx;
748 	off_t base_offset;
749 	uint8_t base_type;
750 	uint64_t base_size;
751 	size_t base_tslen;
752 	off_t delta_data_offset;
753 	uint8_t *delta_buf = NULL;
754 	size_t delta_len;
755 
756 	if (delta_offset >= pack->filesize)
757 		return got_error(GOT_ERR_PACK_OFFSET);
758 	delta_data_offset = delta_offset + tslen;
759 	if (delta_data_offset >= pack->filesize)
760 		return got_error(GOT_ERR_PACK_OFFSET);
761 
762 	if (pack->map == NULL) {
763 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
764 		if (delta_data_offset == -1)
765 			return got_error_from_errno();
766 	}
767 
768 
769 	if (pack->map) {
770 		size_t mapoff = (size_t)delta_data_offset;
771 		memcpy(&id, pack->map + mapoff, sizeof(id));
772 		mapoff += sizeof(id);
773 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
774 		    mapoff, pack->filesize - mapoff);
775 		if (err)
776 			goto done;
777 	} else {
778 		ssize_t n = read(pack->fd, &id, sizeof(id));
779 		if (n < 0)
780 			return got_error_from_errno();
781 		if (n != sizeof(id))
782 			return got_error(GOT_ERR_BAD_PACKFILE);
783 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
784 		if (err)
785 			goto done;
786 	}
787 
788 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
789 	    delta_data_offset, delta_buf, delta_len);
790 	if (err)
791 		goto done;
792 
793 	/* Delta base must be in the same pack file. */
794 	idx = got_packidx_get_object_idx(packidx, &id);
795 	if (idx == -1) {
796 		err = got_error(GOT_ERR_BAD_PACKFILE);
797 		goto done;
798 	}
799 
800 	base_offset = get_object_offset(packidx, idx);
801 	if (base_offset == (uint64_t)-1) {
802 		err = got_error(GOT_ERR_BAD_PACKIDX);
803 		goto done;
804 	}
805 
806 	if (base_offset >= pack->filesize) {
807 		err = got_error(GOT_ERR_PACK_OFFSET);
808 		goto done;
809 	}
810 
811 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
812 	    pack, base_offset);
813 	if (err)
814 		goto done;
815 
816 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
817 	    base_tslen, base_type, base_size, recursion - 1);
818 done:
819 	if (err)
820 		free(delta_buf);
821 	return err;
822 }
823 
824 static const struct got_error *
825 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
826     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
827     size_t delta_size, unsigned int recursion)
828 {
829 	const struct got_error *err = NULL;
830 
831 	if (--recursion == 0)
832 		return got_error(GOT_ERR_RECURSION);
833 
834 	switch (delta_type) {
835 	case GOT_OBJ_TYPE_COMMIT:
836 	case GOT_OBJ_TYPE_TREE:
837 	case GOT_OBJ_TYPE_BLOB:
838 	case GOT_OBJ_TYPE_TAG:
839 		/* Plain types are the final delta base. Recursion ends. */
840 		err = add_delta(deltas, delta_offset, tslen, delta_type,
841 		    delta_size, 0, NULL, 0);
842 		break;
843 	case GOT_OBJ_TYPE_OFFSET_DELTA:
844 		err = resolve_offset_delta(deltas, packidx, pack,
845 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
846 		break;
847 	case GOT_OBJ_TYPE_REF_DELTA:
848 		err = resolve_ref_delta(deltas, packidx, pack,
849 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
850 		break;
851 	default:
852 		return got_error(GOT_ERR_OBJ_TYPE);
853 	}
854 
855 	return err;
856 }
857 
858 static const struct got_error *
859 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
860     struct got_pack *pack, struct got_object_id *id, off_t offset,
861     size_t tslen, int delta_type, size_t delta_size)
862 {
863 	const struct got_error *err = NULL;
864 	int resolved_type;
865 
866 	*obj = calloc(1, sizeof(**obj));
867 	if (*obj == NULL)
868 		return got_error_from_errno();
869 
870 	(*obj)->flags = 0;
871 	(*obj)->hdrlen = 0;
872 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
873 	if (id)
874 		memcpy(&(*obj)->id, id, sizeof((*obj)->id));
875 	(*obj)->pack_offset = offset + tslen;
876 
877 	(*obj)->path_packfile = strdup(pack->path_packfile);
878 	if ((*obj)->path_packfile == NULL) {
879 		err = got_error_from_errno();
880 		goto done;
881 	}
882 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
883 
884 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
885 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
886 
887 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
888 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
889 	if (err)
890 		goto done;
891 
892 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
893 	if (err)
894 		goto done;
895 	(*obj)->type = resolved_type;
896 
897 done:
898 	if (err) {
899 		got_object_close(*obj);
900 		*obj = NULL;
901 	}
902 	return err;
903 }
904 
905 const struct got_error *
906 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
907     struct got_packidx *packidx, int idx, struct got_object_id *id)
908 {
909 	const struct got_error *err = NULL;
910 	off_t offset;
911 	uint8_t type;
912 	uint64_t size;
913 	size_t tslen;
914 
915 	*obj = NULL;
916 
917 	offset = get_object_offset(packidx, idx);
918 	if (offset == (uint64_t)-1)
919 		return got_error(GOT_ERR_BAD_PACKIDX);
920 
921 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
922 	if (err)
923 		return err;
924 
925 	switch (type) {
926 	case GOT_OBJ_TYPE_COMMIT:
927 	case GOT_OBJ_TYPE_TREE:
928 	case GOT_OBJ_TYPE_BLOB:
929 	case GOT_OBJ_TYPE_TAG:
930 		err = open_plain_object(obj, pack->path_packfile, id, type,
931 		    offset + tslen, size);
932 		break;
933 	case GOT_OBJ_TYPE_OFFSET_DELTA:
934 	case GOT_OBJ_TYPE_REF_DELTA:
935 		err = open_delta_object(obj, packidx, pack, id, offset,
936 		    tslen, type, size);
937 		break;
938 	default:
939 		err = got_error(GOT_ERR_OBJ_TYPE);
940 		break;
941 	}
942 
943 	return err;
944 }
945 
946 static const struct got_error *
947 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
948 {
949 	struct got_delta *delta;
950 	uint64_t base_size = 0, result_size = 0;
951 
952 	*max_size = 0;
953 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
954 		/* Plain object types are the delta base. */
955 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
956 		    delta->type != GOT_OBJ_TYPE_TREE &&
957 		    delta->type != GOT_OBJ_TYPE_BLOB &&
958 		    delta->type != GOT_OBJ_TYPE_TAG) {
959 			const struct got_error *err;
960 			err = got_delta_get_sizes(&base_size, &result_size,
961 			    delta->delta_buf, delta->delta_len);
962 			if (err)
963 				return err;
964 		} else
965 			base_size = delta->size;
966 		if (base_size > *max_size)
967 			*max_size = base_size;
968 		if (result_size > *max_size)
969 			*max_size = result_size;
970 	}
971 
972 	return NULL;
973 }
974 
975 static const struct got_error *
976 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
977     struct got_pack *pack, FILE *outfile)
978 {
979 	const struct got_error *err = NULL;
980 	struct got_delta *delta;
981 	FILE *base_file = NULL, *accum_file = NULL;
982 	uint8_t *base_buf = NULL, *accum_buf = NULL;
983 	size_t accum_size = 0;
984 	uint64_t max_size;
985 	int n = 0;
986 
987 	*result_size = 0;
988 
989 	if (SIMPLEQ_EMPTY(&deltas->entries))
990 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
991 
992 	/* We process small enough files entirely in memory for speed. */
993 	err = get_delta_chain_max_size(&max_size, deltas);
994 	if (err)
995 		return err;
996 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
997 		accum_buf = malloc(max_size);
998 		if (accum_buf == NULL)
999 			return got_error_from_errno();
1000 	} else {
1001 		base_file = got_opentemp();
1002 		if (base_file == NULL)
1003 			return got_error_from_errno();
1004 
1005 		accum_file = got_opentemp();
1006 		if (accum_file == NULL) {
1007 			err = got_error_from_errno();
1008 			fclose(base_file);
1009 			return err;
1010 		}
1011 	}
1012 
1013 	/* Deltas are ordered in ascending order. */
1014 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1015 		if (n == 0) {
1016 			size_t base_len, mapoff;
1017 			off_t delta_data_offset;
1018 
1019 			/* Plain object types are the delta base. */
1020 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1021 			    delta->type != GOT_OBJ_TYPE_TREE &&
1022 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1023 			    delta->type != GOT_OBJ_TYPE_TAG) {
1024 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1025 				goto done;
1026 			}
1027 
1028 			delta_data_offset = delta->offset + delta->tslen;
1029 			if (delta_data_offset >= pack->filesize) {
1030 				err = got_error(GOT_ERR_PACK_OFFSET);
1031 				goto done;
1032 			}
1033 			if (pack->map == NULL) {
1034 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1035 				    == -1) {
1036 					err = got_error_from_errno();
1037 					goto done;
1038 				}
1039 			}
1040 			if (base_file) {
1041 				if (pack->map) {
1042 					mapoff = (size_t)delta_data_offset;
1043 					err = got_inflate_to_file_mmap(
1044 					    &base_len, pack->map, mapoff,
1045 					    pack->filesize - mapoff, base_file);
1046 				} else
1047 					err = got_inflate_to_file_fd(&base_len,
1048 					    pack->fd, base_file);
1049 			} else {
1050 				if (pack->map) {
1051 					mapoff = (size_t)delta_data_offset;
1052 					err = got_inflate_to_mem_mmap(&base_buf,
1053 					    &base_len, pack->map, mapoff,
1054 					    pack->filesize - mapoff);
1055 				} else
1056 					err = got_inflate_to_mem_fd(&base_buf,
1057 					    &base_len, pack->fd);
1058 				if (base_len < max_size) {
1059 					uint8_t *p;
1060 					p = reallocarray(base_buf, 1, max_size);
1061 					if (p == NULL) {
1062 						err = got_error_from_errno();
1063 						goto done;
1064 					}
1065 					base_buf = p;
1066 				}
1067 			}
1068 			if (err)
1069 				goto done;
1070 			n++;
1071 			if (base_file)
1072 				rewind(base_file);
1073 			continue;
1074 		}
1075 
1076 		if (base_buf) {
1077 			err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1078 			    delta->delta_len, accum_buf, &accum_size);
1079 			n++;
1080 		} else {
1081 			err = got_delta_apply(base_file, delta->delta_buf,
1082 			    delta->delta_len,
1083 			    /* Final delta application writes to output file. */
1084 			    ++n < deltas->nentries ? accum_file : outfile,
1085 			    &accum_size);
1086 		}
1087 		if (err)
1088 			goto done;
1089 
1090 		if (n < deltas->nentries) {
1091 			/* Accumulated delta becomes the new base. */
1092 			if (base_buf) {
1093 				uint8_t *tmp = accum_buf;
1094 				accum_buf = base_buf;
1095 				base_buf = tmp;
1096 			} else {
1097 				FILE *tmp = accum_file;
1098 				accum_file = base_file;
1099 				base_file = tmp;
1100 				rewind(base_file);
1101 				rewind(accum_file);
1102 			}
1103 		}
1104 	}
1105 
1106 done:
1107 	free(base_buf);
1108 	if (accum_buf) {
1109 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1110 		free(accum_buf);
1111 		if (len != accum_size)
1112 			err = got_ferror(outfile, GOT_ERR_IO);
1113 	}
1114 	if (base_file)
1115 		fclose(base_file);
1116 	if (accum_file)
1117 		fclose(accum_file);
1118 	rewind(outfile);
1119 	if (err == NULL)
1120 		*result_size = accum_size;
1121 	return err;
1122 }
1123 
1124 static const struct got_error *
1125 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1126     struct got_delta_chain *deltas, struct got_pack *pack)
1127 {
1128 	const struct got_error *err = NULL;
1129 	struct got_delta *delta;
1130 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1131 	size_t accum_size;
1132 	uint64_t max_size;
1133 	int n = 0;
1134 
1135 	*outbuf = NULL;
1136 	*outlen = 0;
1137 
1138 	if (SIMPLEQ_EMPTY(&deltas->entries))
1139 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1140 
1141 	err = get_delta_chain_max_size(&max_size, deltas);
1142 	if (err)
1143 		return err;
1144 	accum_buf = malloc(max_size);
1145 	if (accum_buf == NULL)
1146 		return got_error_from_errno();
1147 
1148 	/* Deltas are ordered in ascending order. */
1149 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1150 		if (n == 0) {
1151 			size_t base_len;
1152 			size_t delta_data_offset;
1153 
1154 			/* Plain object types are the delta base. */
1155 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1156 			    delta->type != GOT_OBJ_TYPE_TREE &&
1157 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1158 			    delta->type != GOT_OBJ_TYPE_TAG) {
1159 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1160 				goto done;
1161 			}
1162 
1163 			delta_data_offset = delta->offset + delta->tslen;
1164 			if (delta_data_offset >= pack->filesize) {
1165 				err = got_error(GOT_ERR_PACK_OFFSET);
1166 				goto done;
1167 			}
1168 			if (pack->map) {
1169 				size_t mapoff = (size_t)delta_data_offset;
1170 				err = got_inflate_to_mem_mmap(&base_buf,
1171 				    &base_len, pack->map, mapoff,
1172 				    pack->filesize - mapoff);
1173 			} else {
1174 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1175 				    == -1) {
1176 					err = got_error_from_errno();
1177 					goto done;
1178 				}
1179 				err = got_inflate_to_mem_fd(&base_buf,
1180 				    &base_len, pack->fd);
1181 			}
1182 			if (err)
1183 				goto done;
1184 			if (base_len < max_size) {
1185 				uint8_t *p;
1186 				p = reallocarray(base_buf, 1, max_size);
1187 				if (p == NULL) {
1188 					err = got_error_from_errno();
1189 					goto done;
1190 				}
1191 				base_buf = p;
1192 			}
1193 			n++;
1194 			continue;
1195 		}
1196 
1197 		err = got_delta_apply_in_mem(base_buf, delta->delta_buf,
1198 		    delta->delta_len, accum_buf, &accum_size);
1199 		n++;
1200 		if (err)
1201 			goto done;
1202 
1203 		if (n < deltas->nentries) {
1204 			/* Accumulated delta becomes the new base. */
1205 			uint8_t *tmp = accum_buf;
1206 			accum_buf = base_buf;
1207 			base_buf = tmp;
1208 		}
1209 	}
1210 
1211 done:
1212 	free(base_buf);
1213 	if (err) {
1214 		free(accum_buf);
1215 		*outbuf = NULL;
1216 		*outlen = 0;
1217 	} else {
1218 		*outbuf = accum_buf;
1219 		*outlen = accum_size;
1220 	}
1221 	return err;
1222 }
1223 
1224 const struct got_error *
1225 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1226     FILE *outfile)
1227 {
1228 	const struct got_error *err = NULL;
1229 
1230 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1231 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1232 
1233 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1234 		if (obj->pack_offset >= pack->filesize)
1235 			return got_error(GOT_ERR_PACK_OFFSET);
1236 
1237 		if (pack->map) {
1238 			size_t mapoff = (size_t)obj->pack_offset;
1239 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1240 			    mapoff, pack->filesize - mapoff, outfile);
1241 		} else {
1242 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1243 				return got_error_from_errno();
1244 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1245 			    outfile);
1246 		}
1247 	} else
1248 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1249 		    outfile);
1250 
1251 	return err;
1252 }
1253 
1254 const struct got_error *
1255 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1256     struct got_object *obj, struct got_pack *pack)
1257 {
1258 	const struct got_error *err = NULL;
1259 
1260 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1261 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1262 
1263 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1264 		if (obj->pack_offset >= pack->filesize)
1265 			return got_error(GOT_ERR_PACK_OFFSET);
1266 		if (pack->map) {
1267 			size_t mapoff = (size_t)obj->pack_offset;
1268 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1269 			    mapoff, pack->filesize - mapoff);
1270 		} else {
1271 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1272 				return got_error_from_errno();
1273 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1274 		}
1275 	} else
1276 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1277 
1278 	return err;
1279 }