1 /*
2  * Copyright (c) 2018, 2019, 2020 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/types.h>
18 #include <sys/stat.h>
19 #include <sys/uio.h>
20 #include <sys/mman.h>
21 
22 #include <fcntl.h>
23 #include <errno.h>
24 #include <stdio.h>
25 #include <stdint.h>
26 #include <stdlib.h>
27 #include <string.h>
28 #include <limits.h>
29 #include <unistd.h>
30 #include <zlib.h>
31 
32 #include "got_error.h"
33 #include "got_object.h"
34 #include "got_path.h"
35 
36 #include "got_lib_sha1.h"
37 #include "got_lib_delta.h"
38 #include "got_lib_delta_cache.h"
39 #include "got_lib_inflate.h"
40 #include "got_lib_object.h"
41 #include "got_lib_object_parse.h"
42 #include "got_lib_privsep.h"
43 #include "got_lib_pack.h"
44 
45 #ifndef nitems
46 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
47 #endif
48 
49 #ifndef MIN
50 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
51 #endif
52 
53 static const struct got_error *
54 verify_fanout_table(uint32_t *fanout_table)
55 {
56 	int i;
57 
58 	for (i = 0; i < 0xff - 1; i++) {
59 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
60 			return got_error(GOT_ERR_BAD_PACKIDX);
61 	}
62 
63 	return NULL;
64 }
65 
66 const struct got_error *
67 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
68 {
69 	const struct got_error *err = NULL;
70 	struct got_packidx_v2_hdr *h;
71 	SHA1_CTX ctx;
72 	uint8_t sha1[SHA1_DIGEST_LENGTH];
73 	size_t nobj, len_fanout, len_ids, offset, remain;
74 	ssize_t n;
75 	int i;
76 
77 	SHA1Init(&ctx);
78 
79 	h = &p->hdr;
80 	offset = 0;
81 	remain = p->len;
82 
83 	if (remain < sizeof(*h->magic)) {
84 		err = got_error(GOT_ERR_BAD_PACKIDX);
85 		goto done;
86 	}
87 	if (p->map)
88 		h->magic = (uint32_t *)(p->map + offset);
89 	else {
90 		h->magic = malloc(sizeof(*h->magic));
91 		if (h->magic == NULL) {
92 			err = got_error_from_errno("malloc");
93 			goto done;
94 		}
95 		n = read(p->fd, h->magic, sizeof(*h->magic));
96 		if (n < 0) {
97 			err = got_error_from_errno("read");
98 			goto done;
99 		} else if (n != sizeof(*h->magic)) {
100 			err = got_error(GOT_ERR_BAD_PACKIDX);
101 			goto done;
102 		}
103 	}
104 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
105 		err = got_error(GOT_ERR_BAD_PACKIDX);
106 		goto done;
107 	}
108 	offset += sizeof(*h->magic);
109 	remain -= sizeof(*h->magic);
110 
111 	if (verify)
112 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
113 
114 	if (remain < sizeof(*h->version)) {
115 		err = got_error(GOT_ERR_BAD_PACKIDX);
116 		goto done;
117 	}
118 	if (p->map)
119 		h->version = (uint32_t *)(p->map + offset);
120 	else {
121 		h->version = malloc(sizeof(*h->version));
122 		if (h->version == NULL) {
123 			err = got_error_from_errno("malloc");
124 			goto done;
125 		}
126 		n = read(p->fd, h->version, sizeof(*h->version));
127 		if (n < 0) {
128 			err = got_error_from_errno("read");
129 			goto done;
130 		} else if (n != sizeof(*h->version)) {
131 			err = got_error(GOT_ERR_BAD_PACKIDX);
132 			goto done;
133 		}
134 	}
135 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
136 		err = got_error(GOT_ERR_BAD_PACKIDX);
137 		goto done;
138 	}
139 	offset += sizeof(*h->version);
140 	remain -= sizeof(*h->version);
141 
142 	if (verify)
143 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
144 
145 	len_fanout =
146 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
147 	if (remain < len_fanout) {
148 		err = got_error(GOT_ERR_BAD_PACKIDX);
149 		goto done;
150 	}
151 	if (p->map)
152 		h->fanout_table = (uint32_t *)(p->map + offset);
153 	else {
154 		h->fanout_table = malloc(len_fanout);
155 		if (h->fanout_table == NULL) {
156 			err = got_error_from_errno("malloc");
157 			goto done;
158 		}
159 		n = read(p->fd, h->fanout_table, len_fanout);
160 		if (n < 0) {
161 			err = got_error_from_errno("read");
162 			goto done;
163 		} else if (n != len_fanout) {
164 			err = got_error(GOT_ERR_BAD_PACKIDX);
165 			goto done;
166 		}
167 	}
168 	err = verify_fanout_table(h->fanout_table);
169 	if (err)
170 		goto done;
171 	if (verify)
172 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
173 	offset += len_fanout;
174 	remain -= len_fanout;
175 
176 	nobj = be32toh(h->fanout_table[0xff]);
177 	len_ids = nobj * sizeof(*h->sorted_ids);
178 	if (len_ids <= nobj || len_ids > remain) {
179 		err = got_error(GOT_ERR_BAD_PACKIDX);
180 		goto done;
181 	}
182 	if (p->map)
183 		h->sorted_ids =
184 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
185 	else {
186 		h->sorted_ids = malloc(len_ids);
187 		if (h->sorted_ids == NULL) {
188 			err = got_error(GOT_ERR_BAD_PACKIDX);
189 			goto done;
190 		}
191 		n = read(p->fd, h->sorted_ids, len_ids);
192 		if (n < 0)
193 			err = got_error_from_errno("read");
194 		else if (n != len_ids) {
195 			err = got_error(GOT_ERR_BAD_PACKIDX);
196 			goto done;
197 		}
198 	}
199 	if (verify)
200 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
201 	offset += len_ids;
202 	remain -= len_ids;
203 
204 	if (remain < nobj * sizeof(*h->crc32)) {
205 		err = got_error(GOT_ERR_BAD_PACKIDX);
206 		goto done;
207 	}
208 	if (p->map)
209 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
210 	else {
211 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
212 		if (h->crc32 == NULL) {
213 			err = got_error_from_errno("malloc");
214 			goto done;
215 		}
216 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
217 		if (n < 0)
218 			err = got_error_from_errno("read");
219 		else if (n != nobj * sizeof(*h->crc32)) {
220 			err = got_error(GOT_ERR_BAD_PACKIDX);
221 			goto done;
222 		}
223 	}
224 	if (verify)
225 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
226 	remain -= nobj * sizeof(*h->crc32);
227 	offset += nobj * sizeof(*h->crc32);
228 
229 	if (remain < nobj * sizeof(*h->offsets)) {
230 		err = got_error(GOT_ERR_BAD_PACKIDX);
231 		goto done;
232 	}
233 	if (p->map)
234 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
235 	else {
236 		h->offsets = malloc(nobj * sizeof(*h->offsets));
237 		if (h->offsets == NULL) {
238 			err = got_error_from_errno("malloc");
239 			goto done;
240 		}
241 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
242 		if (n < 0)
243 			err = got_error_from_errno("read");
244 		else if (n != nobj * sizeof(*h->offsets)) {
245 			err = got_error(GOT_ERR_BAD_PACKIDX);
246 			goto done;
247 		}
248 	}
249 	if (verify)
250 		SHA1Update(&ctx, (uint8_t *)h->offsets,
251 		    nobj * sizeof(*h->offsets));
252 	remain -= nobj * sizeof(*h->offsets);
253 	offset += nobj * sizeof(*h->offsets);
254 
255 	/* Large file offsets are contained only in files > 2GB. */
256 	if (verify || packfile_size > 0x7fffffff) {
257 		for (i = 0; i < nobj; i++) {
258 			uint32_t o = h->offsets[i];
259 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
260 				p->nlargeobj++;
261 		}
262 	}
263 	if (p->nlargeobj == 0)
264 		goto checksum;
265 	else if (packfile_size <= 0x7fffffff) {
266 		err = got_error(GOT_ERR_BAD_PACKIDX);
267 		goto done;
268 	}
269 
270 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
271 		err = got_error(GOT_ERR_BAD_PACKIDX);
272 		goto done;
273 	}
274 	if (p->map)
275 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
276 	else {
277 		h->large_offsets = malloc(p->nlargeobj *
278 		    sizeof(*h->large_offsets));
279 		if (h->large_offsets == NULL) {
280 			err = got_error_from_errno("malloc");
281 			goto done;
282 		}
283 		n = read(p->fd, h->large_offsets,
284 		    p->nlargeobj * sizeof(*h->large_offsets));
285 		if (n < 0)
286 			err = got_error_from_errno("read");
287 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
288 			err = got_error(GOT_ERR_BAD_PACKIDX);
289 			goto done;
290 		}
291 	}
292 	if (verify)
293 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
294 		    p->nlargeobj * sizeof(*h->large_offsets));
295 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
296 	offset += p->nlargeobj * sizeof(*h->large_offsets);
297 
298 checksum:
299 	if (remain < sizeof(*h->trailer)) {
300 		err = got_error(GOT_ERR_BAD_PACKIDX);
301 		goto done;
302 	}
303 	if (p->map)
304 		h->trailer =
305 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
306 	else {
307 		h->trailer = malloc(sizeof(*h->trailer));
308 		if (h->trailer == NULL) {
309 			err = got_error_from_errno("malloc");
310 			goto done;
311 		}
312 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
313 		if (n < 0)
314 			err = got_error_from_errno("read");
315 		else if (n != sizeof(*h->trailer)) {
316 			err = got_error(GOT_ERR_BAD_PACKIDX);
317 			goto done;
318 		}
319 	}
320 	if (verify) {
321 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
322 		SHA1Final(sha1, &ctx);
323 		if (memcmp(h->trailer->packidx_sha1, sha1,
324 		    SHA1_DIGEST_LENGTH) != 0)
325 			err = got_error(GOT_ERR_PACKIDX_CSUM);
326 	}
327 done:
328 	return err;
329 }
330 
331 const struct got_error *
332 got_packidx_open(struct got_packidx **packidx,
333     int dir_fd, const char *relpath, int verify)
334 {
335 	const struct got_error *err = NULL;
336 	struct got_packidx *p = NULL;
337 	char *pack_relpath;
338 	struct stat idx_sb, pack_sb;
339 
340 	*packidx = NULL;
341 
342 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
343 	if (err)
344 		return err;
345 
346 	/*
347 	 * Ensure that a corresponding pack file exists.
348 	 * Some Git repositories have this problem. Git seems to ignore
349 	 * the existence of lonely pack index files but we do not.
350 	 */
351 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
352 		if (errno == ENOENT) {
353 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
354 			    "%s", relpath);
355 		} else
356 			err = got_error_from_errno2("fstatat", pack_relpath);
357 		goto done;
358 	}
359 
360 	p = calloc(1, sizeof(*p));
361 	if (p == NULL) {
362 		err = got_error_from_errno("calloc");
363 		goto done;
364 	}
365 
366 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
367 	if (p->fd == -1) {
368 		err = got_error_from_errno2("openat", relpath);
369 		goto done;
370 	}
371 
372 	if (fstat(p->fd, &idx_sb) != 0) {
373 		err = got_error_from_errno2("fstat", relpath);
374 		goto done;
375 	}
376 	p->len = idx_sb.st_size;
377 	if (p->len < sizeof(p->hdr)) {
378 		err = got_error(GOT_ERR_BAD_PACKIDX);
379 		goto done;
380 	}
381 
382 	p->path_packidx = strdup(relpath);
383 	if (p->path_packidx == NULL) {
384 		err = got_error_from_errno("strdup");
385 		goto done;
386 	}
387 
388 #ifndef GOT_PACK_NO_MMAP
389 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
390 	if (p->map == MAP_FAILED) {
391 		if (errno != ENOMEM) {
392 			err = got_error_from_errno("mmap");
393 			goto done;
394 		}
395 		p->map = NULL; /* fall back to read(2) */
396 	}
397 #endif
398 
399 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
400 done:
401 	if (err) {
402 		if (p)
403 			got_packidx_close(p);
404 	} else
405 		*packidx = p;
406 	free(pack_relpath);
407 	return err;
408 }
409 
410 const struct got_error *
411 got_packidx_close(struct got_packidx *packidx)
412 {
413 	const struct got_error *err = NULL;
414 
415 	free(packidx->path_packidx);
416 	if (packidx->map) {
417 		if (munmap(packidx->map, packidx->len) == -1)
418 			err = got_error_from_errno("munmap");
419 	} else {
420 		free(packidx->hdr.magic);
421 		free(packidx->hdr.version);
422 		free(packidx->hdr.fanout_table);
423 		free(packidx->hdr.sorted_ids);
424 		free(packidx->hdr.crc32);
425 		free(packidx->hdr.offsets);
426 		free(packidx->hdr.large_offsets);
427 		free(packidx->hdr.trailer);
428 	}
429 	if (close(packidx->fd) == -1 && err == NULL)
430 		err = got_error_from_errno("close");
431 	free(packidx->sorted_offsets);
432 	free(packidx->sorted_large_offsets);
433 	free(packidx);
434 
435 	return err;
436 }
437 
438 const struct got_error *
439 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
440 {
441 	size_t size;
442 
443 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
444 	size = strlen(path_packidx) + 2;
445 	if (size < GOT_PACKFILE_NAMELEN + 1)
446 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
447 
448 	*path_packfile = malloc(size);
449 	if (*path_packfile == NULL)
450 		return got_error_from_errno("malloc");
451 
452 	/* Copy up to and excluding ".idx". */
453 	if (strlcpy(*path_packfile, path_packidx,
454 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
455 		return got_error(GOT_ERR_NO_SPACE);
456 
457 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
458 		return got_error(GOT_ERR_NO_SPACE);
459 
460 	return NULL;
461 }
462 
463 off_t
464 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
465 {
466 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
467 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
468 		uint64_t loffset;
469 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
470 		if (idx < 0 || idx >= packidx->nlargeobj ||
471 		    packidx->hdr.large_offsets == NULL)
472 			return -1;
473 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
474 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
475 	}
476 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
477 }
478 
479 int
480 got_packidx_get_object_idx(struct got_packidx *packidx,
481     struct got_object_id *id)
482 {
483 	u_int8_t id0 = id->sha1[0];
484 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
485 	int left = 0, right = totobj - 1;
486 
487 	if (id0 > 0)
488 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
489 
490 	while (left <= right) {
491 		struct got_packidx_object_id *oid;
492 		int i, cmp;
493 
494 		i = ((left + right) / 2);
495 		oid = &packidx->hdr.sorted_ids[i];
496 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
497 		if (cmp == 0)
498 			return i;
499 		else if (cmp > 0)
500 			left = i + 1;
501 		else if (cmp < 0)
502 			right = i - 1;
503 	}
504 
505 	return -1;
506 }
507 
508 static int
509 offset_cmp(const void *pa, const void *pb)
510 {
511 	const struct got_pack_offset_index *a, *b;
512 
513 	a = (const struct got_pack_offset_index *)pa;
514 	b = (const struct got_pack_offset_index *)pb;
515 
516 	if (a->offset < b->offset)
517 		return -1;
518 	else if (a->offset > b->offset)
519 		return 1;
520 
521 	return 0;
522 }
523 
524 static int
525 large_offset_cmp(const void *pa, const void *pb)
526 {
527 	const struct got_pack_large_offset_index *a, *b;
528 
529 	a = (const struct got_pack_large_offset_index *)pa;
530 	b = (const struct got_pack_large_offset_index *)pb;
531 
532 	if (a->offset < b->offset)
533 		return -1;
534 	else if (a->offset > b->offset)
535 		return 1;
536 
537 	return 0;
538 }
539 
540 static const struct got_error *
541 build_offset_index(struct got_packidx *p)
542 {
543 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
544 	unsigned int i, j, k;
545 
546 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
547 	    sizeof(p->sorted_offsets[0]));
548 	if (p->sorted_offsets == NULL)
549 		return got_error_from_errno("calloc");
550 
551 	if (p->nlargeobj > 0) {
552 		p->sorted_large_offsets = calloc(p->nlargeobj,
553 		    sizeof(p->sorted_large_offsets[0]));
554 		if (p->sorted_large_offsets == NULL)
555 			return got_error_from_errno("calloc");
556 	}
557 
558 	j = 0;
559 	k = 0;
560 	for (i = 0; i < nobj; i++) {
561 		uint32_t offset = be32toh(p->hdr.offsets[i]);
562 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
563 			uint64_t loffset;
564 			uint32_t idx;
565 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
566 			if (idx >= p->nlargeobj ||
567 			    p->nlargeobj == 0 ||
568 			    p->hdr.large_offsets == NULL)
569 				return got_error(GOT_ERR_BAD_PACKIDX);
570 			loffset = be64toh(p->hdr.large_offsets[idx]);
571 			p->sorted_large_offsets[j].offset = loffset;
572 			p->sorted_large_offsets[j].idx = i;
573 			j++;
574 		} else {
575 			p->sorted_offsets[k].offset = offset;
576 			p->sorted_offsets[k].idx = i;
577 			k++;
578 		}
579 	}
580 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
581 		return got_error(GOT_ERR_BAD_PACKIDX);
582 
583 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
584 	    sizeof(p->sorted_offsets[0]), offset_cmp);
585 
586 	if (p->sorted_large_offsets)
587 		qsort(p->sorted_large_offsets, p->nlargeobj,
588 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
589 
590 	return NULL;
591 }
592 
593 const struct got_error *
594 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
595 {
596 	const struct got_error *err;
597 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
598 	int i, left, right;
599 
600 	*idx = -1;
601 
602 	if (packidx->sorted_offsets == NULL) {
603 		err = build_offset_index(packidx);
604 		if (err)
605 			return err;
606 	}
607 
608 	if (offset >= 0x7fffffff) {
609 		uint64_t lo;
610 		left = 0, right = packidx->nlargeobj - 1;
611 		while (left <= right) {
612 			i = ((left + right) / 2);
613 			lo = packidx->sorted_large_offsets[i].offset;
614 			if (lo == offset) {
615 				*idx = packidx->sorted_large_offsets[i].idx;
616 				break;
617 			} else if (offset > lo)
618 				left = i + 1;
619 			else if (offset < lo)
620 				right = i - 1;
621 		}
622 	} else {
623 		uint32_t o;
624 		left = 0, right = totobj - packidx->nlargeobj - 1;
625 		while (left <= right) {
626 			i = ((left + right) / 2);
627 			o = packidx->sorted_offsets[i].offset;
628 			if (o == offset) {
629 				*idx = packidx->sorted_offsets[i].idx;
630 				break;
631 			} else if (offset > o)
632 				left = i + 1;
633 			else if (offset < o)
634 				right = i - 1;
635 		}
636 	}
637 
638 	return NULL;
639 }
640 
641 const struct got_error *
642 got_packidx_get_object_id(struct got_object_id *id,
643     struct got_packidx *packidx, int idx)
644 {
645 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
646 	struct got_packidx_object_id *oid;
647 
648 	if (idx < 0 || idx >= totobj)
649 		return got_error(GOT_ERR_NO_OBJ);
650 
651 	oid = &packidx->hdr.sorted_ids[idx];
652 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
653 	return NULL;
654 }
655 
656 const struct got_error *
657 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
658     struct got_packidx *packidx, const char *id_str_prefix)
659 {
660 	const struct got_error *err = NULL;
661 	u_int8_t id0;
662 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
663 	char hex[3];
664 	size_t prefix_len = strlen(id_str_prefix);
665 	struct got_packidx_object_id *oid;
666 	uint32_t i = 0;
667 
668 	STAILQ_INIT(matched_ids);
669 
670 	if (prefix_len < 2)
671 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
672 
673 	hex[0] = id_str_prefix[0];
674 	hex[1] = id_str_prefix[1];
675 	hex[2] = '\0';
676 	if (!got_parse_xdigit(&id0, hex))
677 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
678 
679 	if (id0 > 0)
680 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
681 	oid = &packidx->hdr.sorted_ids[i];
682 	while (i < totobj && oid->sha1[0] == id0) {
683 		char id_str[SHA1_DIGEST_STRING_LENGTH];
684 		struct got_object_qid *qid;
685 		int cmp;
686 
687 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
688 		        return got_error(GOT_ERR_NO_SPACE);
689 
690 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
691 		if (cmp < 0) {
692 			oid = &packidx->hdr.sorted_ids[++i];
693 			continue;
694 		} else if (cmp > 0)
695 			break;
696 
697 		err = got_object_qid_alloc_partial(&qid);
698 		if (err)
699 			break;
700 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
701 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
702 
703 		oid = &packidx->hdr.sorted_ids[++i];
704 	}
705 
706 	if (err)
707 		got_object_id_queue_free(matched_ids);
708 	return err;
709 }
710 
711 static const struct got_error *
712 pack_stop_privsep_child(struct got_pack *pack)
713 {
714 	const struct got_error *err = NULL;
715 
716 	if (pack->privsep_child == NULL)
717 		return NULL;
718 
719 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
720 	if (err)
721 		return err;
722 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
723 	if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
724 		err = got_error_from_errno("close");
725 	free(pack->privsep_child->ibuf);
726 	free(pack->privsep_child);
727 	pack->privsep_child = NULL;
728 	return err;
729 }
730 
731 const struct got_error *
732 got_pack_close(struct got_pack *pack)
733 {
734 	const struct got_error *err = NULL;
735 
736 	err = pack_stop_privsep_child(pack);
737 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
738 		err = got_error_from_errno("munmap");
739 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
740 		err = got_error_from_errno("close");
741 	pack->fd = -1;
742 	free(pack->path_packfile);
743 	pack->path_packfile = NULL;
744 	pack->filesize = 0;
745 	if (pack->delta_cache) {
746 		got_delta_cache_free(pack->delta_cache);
747 		pack->delta_cache = NULL;
748 	}
749 
750 	/*
751 	 * Leave accumfd and basefd alone. They are managed by the
752 	 * repository layer and can be reused.
753 	 */
754 
755 	return err;
756 }
757 
758 const struct got_error *
759 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
760     struct got_pack *pack, off_t offset)
761 {
762 	uint8_t t = 0;
763 	uint64_t s = 0;
764 	uint8_t sizeN;
765 	size_t mapoff = 0;
766 	int i = 0;
767 
768 	*len = 0;
769 
770 	if (offset >= pack->filesize)
771 		return got_error(GOT_ERR_PACK_OFFSET);
772 
773 	if (pack->map) {
774 		mapoff = (size_t)offset;
775 	} else {
776 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
777 			return got_error_from_errno("lseek");
778 	}
779 
780 	do {
781 		/* We do not support size values which don't fit in 64 bit. */
782 		if (i > 9)
783 			return got_error(GOT_ERR_NO_SPACE);
784 
785 		if (pack->map) {
786 			if (mapoff + sizeof(sizeN) >= pack->filesize)
787 				return got_error(GOT_ERR_BAD_PACKFILE);
788 			sizeN = *(pack->map + mapoff);
789 			mapoff += sizeof(sizeN);
790 		} else {
791 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
792 			if (n < 0)
793 				return got_error_from_errno("read");
794 			if (n != sizeof(sizeN))
795 				return got_error(GOT_ERR_BAD_PACKFILE);
796 		}
797 		*len += sizeof(sizeN);
798 
799 		if (i == 0) {
800 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
801 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
802 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
803 		} else {
804 			size_t shift = 4 + 7 * (i - 1);
805 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
806 		}
807 		i++;
808 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
809 
810 	*type = t;
811 	*size = s;
812 	return NULL;
813 }
814 
815 static const struct got_error *
816 open_plain_object(struct got_object **obj, struct got_object_id *id,
817     uint8_t type, off_t offset, size_t size, int idx)
818 {
819 	*obj = calloc(1, sizeof(**obj));
820 	if (*obj == NULL)
821 		return got_error_from_errno("calloc");
822 
823 	(*obj)->type = type;
824 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
825 	(*obj)->pack_idx = idx;
826 	(*obj)->hdrlen = 0;
827 	(*obj)->size = size;
828 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
829 	(*obj)->pack_offset = offset;
830 
831 	return NULL;
832 }
833 
834 static const struct got_error *
835 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
836     off_t delta_offset)
837 {
838 	int64_t o = 0;
839 	uint8_t offN;
840 	int i = 0;
841 
842 	*offset = 0;
843 	*len = 0;
844 
845 	do {
846 		/* We do not support offset values which don't fit in 64 bit. */
847 		if (i > 8)
848 			return got_error(GOT_ERR_NO_SPACE);
849 
850 		if (pack->map) {
851 			size_t mapoff;
852 			mapoff = (size_t)delta_offset + *len;
853 			if (mapoff + sizeof(offN) >= pack->filesize)
854 				return got_error(GOT_ERR_PACK_OFFSET);
855 			offN = *(pack->map + mapoff);
856 		} else {
857 			ssize_t n;
858 			n = read(pack->fd, &offN, sizeof(offN));
859 			if (n < 0)
860 				return got_error_from_errno("read");
861 			if (n != sizeof(offN))
862 				return got_error(GOT_ERR_BAD_PACKFILE);
863 		}
864 		*len += sizeof(offN);
865 
866 		if (i == 0)
867 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
868 		else {
869 			o++;
870 			o <<= 7;
871 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
872 		}
873 		i++;
874 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
875 
876 	*offset = o;
877 	return NULL;
878 }
879 
880 const struct got_error *
881 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
882     struct got_pack *pack, off_t offset, int tslen)
883 {
884 	const struct got_error *err;
885 	int64_t negoffset;
886 	size_t negofflen;
887 
888 	*len = 0;
889 
890 	err = parse_negative_offset(&negoffset, &negofflen, pack,
891 	    offset + tslen);
892 	if (err)
893 		return err;
894 
895 	/* Compute the base object's offset (must be in the same pack file). */
896 	*base_offset = (offset - negoffset);
897 	if (*base_offset <= 0)
898 		return got_error(GOT_ERR_BAD_PACKFILE);
899 
900 	*len = negofflen;
901 	return NULL;
902 }
903 
904 static const struct got_error *
905 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
906     size_t *delta_compressed_len, size_t delta_data_offset,
907     struct got_pack *pack)
908 {
909 	const struct got_error *err = NULL;
910 	size_t consumed = 0;
911 
912 	if (pack->map) {
913 		if (delta_data_offset >= pack->filesize)
914 			return got_error(GOT_ERR_PACK_OFFSET);
915 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
916 		    &consumed, NULL, pack->map, delta_data_offset,
917 		    pack->filesize - delta_data_offset);
918 		if (err)
919 			return err;
920 	} else {
921 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
922 			return got_error_from_errno("lseek");
923 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
924 		    &consumed, NULL, 0, pack->fd);
925 		if (err)
926 			return err;
927 	}
928 
929 	if (delta_compressed_len)
930 		*delta_compressed_len = consumed;
931 
932 	return NULL;
933 }
934 
935 static const struct got_error *
936 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
937     int delta_type, size_t delta_size, size_t delta_data_offset)
938 {
939 	struct got_delta *delta;
940 
941 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
942 	    delta_data_offset);
943 	if (delta == NULL)
944 		return got_error_from_errno("got_delta_open");
945 	/* delta is freed in got_object_close() */
946 	deltas->nentries++;
947 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
948 	return NULL;
949 }
950 
951 static const struct got_error *
952 resolve_offset_delta(struct got_delta_chain *deltas,
953     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
954     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
955 
956 {
957 	const struct got_error *err;
958 	off_t base_offset;
959 	uint8_t base_type;
960 	uint64_t base_size;
961 	size_t base_tslen;
962 	off_t delta_data_offset;
963 	size_t consumed;
964 
965 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
966 	    delta_offset, tslen);
967 	if (err)
968 		return err;
969 
970 	delta_data_offset = delta_offset + tslen + consumed;
971 	if (delta_data_offset >= pack->filesize)
972 		return got_error(GOT_ERR_PACK_OFFSET);
973 
974 	if (pack->map == NULL) {
975 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
976 		if (delta_data_offset == -1)
977 			return got_error_from_errno("lseek");
978 	}
979 
980 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
981 	    delta_data_offset);
982 	if (err)
983 		return err;
984 
985 	/* An offset delta must be in the same packfile. */
986 	if (base_offset >= pack->filesize)
987 		return got_error(GOT_ERR_PACK_OFFSET);
988 
989 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
990 	    &base_tslen, pack, base_offset);
991 	if (err)
992 		return err;
993 
994 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
995 	    base_tslen, base_type, base_size, recursion - 1);
996 }
997 
998 const struct got_error *
999 got_pack_parse_ref_delta(struct got_object_id *id,
1000     struct got_pack *pack, off_t delta_offset, int tslen)
1001 {
1002 	if (pack->map) {
1003 		size_t mapoff = delta_offset + tslen;
1004 		if (mapoff + sizeof(*id) >= pack->filesize)
1005 			return got_error(GOT_ERR_PACK_OFFSET);
1006 		memcpy(id, pack->map + mapoff, sizeof(*id));
1007 	} else {
1008 		ssize_t n;
1009 		n = read(pack->fd, id, sizeof(*id));
1010 		if (n < 0)
1011 			return got_error_from_errno("read");
1012 		if (n != sizeof(*id))
1013 			return got_error(GOT_ERR_BAD_PACKFILE);
1014 	}
1015 
1016 	return NULL;
1017 }
1018 
1019 static const struct got_error *
1020 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1021     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1022     size_t delta_size, unsigned int recursion)
1023 {
1024 	const struct got_error *err;
1025 	struct got_object_id id;
1026 	int idx;
1027 	off_t base_offset;
1028 	uint8_t base_type;
1029 	uint64_t base_size;
1030 	size_t base_tslen;
1031 	off_t delta_data_offset;
1032 
1033 	if (delta_offset + tslen >= pack->filesize)
1034 		return got_error(GOT_ERR_PACK_OFFSET);
1035 
1036 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1037 	if (err)
1038 		return err;
1039 	if (pack->map) {
1040 		delta_data_offset = delta_offset + tslen + sizeof(id);
1041 	} else {
1042 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1043 		if (delta_data_offset == -1)
1044 			return got_error_from_errno("lseek");
1045 	}
1046 
1047 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1048 	    delta_data_offset);
1049 	if (err)
1050 		return err;
1051 
1052 	/* Delta base must be in the same pack file. */
1053 	idx = got_packidx_get_object_idx(packidx, &id);
1054 	if (idx == -1)
1055 		return got_error(GOT_ERR_NO_OBJ);
1056 
1057 	base_offset = got_packidx_get_object_offset(packidx, idx);
1058 	if (base_offset == (uint64_t)-1)
1059 		return got_error(GOT_ERR_BAD_PACKIDX);
1060 
1061 	if (base_offset >= pack->filesize)
1062 		return got_error(GOT_ERR_PACK_OFFSET);
1063 
1064 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1065 	    &base_tslen, pack, base_offset);
1066 	if (err)
1067 		return err;
1068 
1069 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1070 	    base_tslen, base_type, base_size, recursion - 1);
1071 }
1072 
1073 const struct got_error *
1074 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1075     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1076     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1077 {
1078 	const struct got_error *err = NULL;
1079 
1080 	if (--recursion == 0)
1081 		return got_error(GOT_ERR_RECURSION);
1082 
1083 	switch (delta_type) {
1084 	case GOT_OBJ_TYPE_COMMIT:
1085 	case GOT_OBJ_TYPE_TREE:
1086 	case GOT_OBJ_TYPE_BLOB:
1087 	case GOT_OBJ_TYPE_TAG:
1088 		/* Plain types are the final delta base. Recursion ends. */
1089 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1090 		    delta_size, 0);
1091 		break;
1092 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1093 		err = resolve_offset_delta(deltas, packidx, pack,
1094 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1095 		break;
1096 	case GOT_OBJ_TYPE_REF_DELTA:
1097 		err = resolve_ref_delta(deltas, packidx, pack,
1098 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1099 		break;
1100 	default:
1101 		return got_error(GOT_ERR_OBJ_TYPE);
1102 	}
1103 
1104 	return err;
1105 }
1106 
1107 static const struct got_error *
1108 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1109     struct got_pack *pack, struct got_object_id *id, off_t offset,
1110     size_t tslen, int delta_type, size_t delta_size, int idx)
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("calloc");
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 	STAILQ_INIT(&(*obj)->deltas.entries);
1126 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1127 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1128 	(*obj)->pack_idx = idx;
1129 
1130 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1131 	    offset, tslen, delta_type, delta_size,
1132 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1133 	if (err)
1134 		goto done;
1135 
1136 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1137 	if (err)
1138 		goto done;
1139 	(*obj)->type = resolved_type;
1140 done:
1141 	if (err) {
1142 		got_object_close(*obj);
1143 		*obj = NULL;
1144 	}
1145 	return err;
1146 }
1147 
1148 const struct got_error *
1149 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1150     struct got_packidx *packidx, int idx, struct got_object_id *id)
1151 {
1152 	const struct got_error *err = NULL;
1153 	off_t offset;
1154 	uint8_t type;
1155 	uint64_t size;
1156 	size_t tslen;
1157 
1158 	*obj = NULL;
1159 
1160 	offset = got_packidx_get_object_offset(packidx, idx);
1161 	if (offset == (uint64_t)-1)
1162 		return got_error(GOT_ERR_BAD_PACKIDX);
1163 
1164 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1165 	    pack, offset);
1166 	if (err)
1167 		return err;
1168 
1169 	switch (type) {
1170 	case GOT_OBJ_TYPE_COMMIT:
1171 	case GOT_OBJ_TYPE_TREE:
1172 	case GOT_OBJ_TYPE_BLOB:
1173 	case GOT_OBJ_TYPE_TAG:
1174 		err = open_plain_object(obj, id, type, offset + tslen,
1175 		    size, idx);
1176 		break;
1177 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1178 	case GOT_OBJ_TYPE_REF_DELTA:
1179 		err = open_delta_object(obj, packidx, pack, id, offset,
1180 		    tslen, type, size, idx);
1181 		break;
1182 	default:
1183 		err = got_error(GOT_ERR_OBJ_TYPE);
1184 		break;
1185 	}
1186 
1187 	return err;
1188 }
1189 
1190 const struct got_error *
1191 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1192     struct got_delta_chain *deltas, struct got_pack *pack)
1193 {
1194 	struct got_delta *delta;
1195 	uint64_t base_size = 0, result_size = 0;
1196 
1197 	*max_size = 0;
1198 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1199 		/* Plain object types are the delta base. */
1200 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1201 		    delta->type != GOT_OBJ_TYPE_TREE &&
1202 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1203 		    delta->type != GOT_OBJ_TYPE_TAG) {
1204 			const struct got_error *err;
1205 			uint8_t *delta_buf;
1206 			size_t delta_len;
1207 			int cached = 1;
1208 
1209 			got_delta_cache_get(&delta_buf, &delta_len,
1210 			    pack->delta_cache, delta->data_offset);
1211 			if (delta_buf == NULL) {
1212 				cached = 0;
1213 				err = read_delta_data(&delta_buf, &delta_len,
1214 				    NULL, delta->data_offset, pack);
1215 				if (err)
1216 					return err;
1217 				err = got_delta_cache_add(pack->delta_cache,
1218 				    delta->data_offset, delta_buf, delta_len);
1219 				if (err == NULL)
1220 					cached = 1;
1221 				else if (err->code != GOT_ERR_NO_SPACE) {
1222 					free(delta_buf);
1223 					return err;
1224 				}
1225 			}
1226 			err = got_delta_get_sizes(&base_size, &result_size,
1227 			    delta_buf, delta_len);
1228 			if (!cached)
1229 				free(delta_buf);
1230 			if (err)
1231 				return err;
1232 		} else
1233 			base_size = delta->size;
1234 		if (base_size > *max_size)
1235 			*max_size = base_size;
1236 		if (result_size > *max_size)
1237 			*max_size = result_size;
1238 	}
1239 
1240 	return NULL;
1241 }
1242 
1243 const struct got_error *
1244 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1245     struct got_pack *pack)
1246 {
1247 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1248 		return got_error(GOT_ERR_OBJ_TYPE);
1249 
1250 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1251 }
1252 
1253 const struct got_error *
1254 got_pack_dump_delta_chain_to_file(size_t *result_size,
1255     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1256     FILE *base_file, FILE *accum_file)
1257 {
1258 	const struct got_error *err = NULL;
1259 	struct got_delta *delta;
1260 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1261 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1262 	/* We process small enough files entirely in memory for speed. */
1263 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1264 	uint64_t max_size = 0;
1265 	int n = 0;
1266 
1267 	*result_size = 0;
1268 
1269 	if (STAILQ_EMPTY(&deltas->entries))
1270 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1271 
1272 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1273 		return got_error_from_errno("fseeko");
1274 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1275 		return got_error_from_errno("fseeko");
1276 
1277 	/* Deltas are ordered in ascending order. */
1278 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1279 		uint64_t base_size, result_size = 0;
1280 		int cached = 1;
1281 		if (n == 0) {
1282 			size_t mapoff;
1283 			off_t delta_data_offset;
1284 
1285 			/* Plain object types are the delta base. */
1286 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1287 			    delta->type != GOT_OBJ_TYPE_TREE &&
1288 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1289 			    delta->type != GOT_OBJ_TYPE_TAG) {
1290 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1291 				goto done;
1292 			}
1293 
1294 			delta_data_offset = delta->offset + delta->tslen;
1295 			if (delta_data_offset >= pack->filesize) {
1296 				err = got_error(GOT_ERR_PACK_OFFSET);
1297 				goto done;
1298 			}
1299 			if (pack->map == NULL) {
1300 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1301 				    == -1) {
1302 					err = got_error_from_errno("lseek");
1303 					goto done;
1304 				}
1305 			}
1306 			if (delta->size > max_size)
1307 				max_size = delta->size;
1308 			if (max_size > max_bufsize) {
1309 				if (pack->map) {
1310 					mapoff = (size_t)delta_data_offset;
1311 					err = got_inflate_to_file_mmap(
1312 					    &base_bufsz, NULL, NULL, pack->map,
1313 					    mapoff, pack->filesize - mapoff,
1314 					    base_file);
1315 				} else
1316 					err = got_inflate_to_file_fd(
1317 					    &base_bufsz, NULL, NULL, pack->fd,
1318 					    base_file);
1319 			} else {
1320 				accum_buf = malloc(max_size);
1321 				if (accum_buf == NULL) {
1322 					err = got_error_from_errno("malloc");
1323 					goto done;
1324 				}
1325 				accum_bufsz = max_size;
1326 				if (pack->map) {
1327 					mapoff = (size_t)delta_data_offset;
1328 					err = got_inflate_to_mem_mmap(&base_buf,
1329 					    &base_bufsz, NULL, NULL,
1330 					    pack->map, mapoff,
1331 					    pack->filesize - mapoff);
1332 				} else
1333 					err = got_inflate_to_mem_fd(&base_buf,
1334 					    &base_bufsz, NULL, NULL, max_size,
1335 					    pack->fd);
1336 			}
1337 			if (err)
1338 				goto done;
1339 			n++;
1340 			if (base_buf == NULL)
1341 				rewind(base_file);
1342 			continue;
1343 		}
1344 
1345 		got_delta_cache_get(&delta_buf, &delta_len,
1346 		    pack->delta_cache, delta->data_offset);
1347 		if (delta_buf == NULL) {
1348 			cached = 0;
1349 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1350 			    delta->data_offset, pack);
1351 			if (err)
1352 				goto done;
1353 			err = got_delta_cache_add(pack->delta_cache,
1354 			    delta->data_offset, delta_buf, delta_len);
1355 			if (err == NULL)
1356 				cached = 1;
1357 			else if (err->code != GOT_ERR_NO_SPACE) {
1358 				free(delta_buf);
1359 				goto done;
1360 			}
1361 		}
1362 
1363 		err = got_delta_get_sizes(&base_size, &result_size,
1364 		    delta_buf, delta_len);
1365 		if (err)
1366 			goto done;
1367 		if (base_size > max_size)
1368 			max_size = base_size;
1369 		if (result_size > max_size)
1370 			max_size = result_size;
1371 
1372 		if (base_buf && max_size > max_bufsize) {
1373 			/* Switch from buffers to temporary files. */
1374 			size_t w = fwrite(base_buf, 1, base_bufsz,
1375 			    base_file);
1376 			if (w != base_bufsz) {
1377 				err = got_ferror(outfile, GOT_ERR_IO);
1378 				goto done;
1379 			}
1380 			free(base_buf);
1381 			base_buf = NULL;
1382 			free(accum_buf);
1383 			accum_buf = NULL;
1384 		}
1385 
1386 		if (base_buf && max_size > base_bufsz) {
1387 			uint8_t *p = realloc(base_buf, max_size);
1388 			if (p == NULL) {
1389 				err = got_error_from_errno("realloc");
1390 				goto done;
1391 			}
1392 			base_buf = p;
1393 			base_bufsz = max_size;
1394 		}
1395 
1396 		if (accum_buf && max_size > accum_bufsz) {
1397 			uint8_t *p = realloc(accum_buf, max_size);
1398 			if (p == NULL) {
1399 				err = got_error_from_errno("realloc");
1400 				goto done;
1401 			}
1402 			accum_buf = p;
1403 			accum_bufsz = max_size;
1404 		}
1405 
1406 		if (base_buf) {
1407 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1408 			    delta_buf, delta_len, accum_buf,
1409 			    &accum_size, max_size);
1410 			n++;
1411 		} else {
1412 			err = got_delta_apply(base_file, delta_buf,
1413 			    delta_len,
1414 			    /* Final delta application writes to output file. */
1415 			    ++n < deltas->nentries ? accum_file : outfile,
1416 			    &accum_size);
1417 		}
1418 		if (!cached)
1419 			free(delta_buf);
1420 		if (err)
1421 			goto done;
1422 
1423 		if (n < deltas->nentries) {
1424 			/* Accumulated delta becomes the new base. */
1425 			if (base_buf) {
1426 				uint8_t *tmp = accum_buf;
1427 				size_t tmp_size = accum_bufsz;
1428 				accum_buf = base_buf;
1429 				accum_bufsz = base_bufsz;
1430 				base_buf = tmp;
1431 				base_bufsz = tmp_size;
1432 			} else {
1433 				FILE *tmp = accum_file;
1434 				accum_file = base_file;
1435 				base_file = tmp;
1436 				rewind(base_file);
1437 				rewind(accum_file);
1438 			}
1439 		}
1440 	}
1441 
1442 done:
1443 	free(base_buf);
1444 	if (accum_buf) {
1445 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1446 		free(accum_buf);
1447 		if (len != accum_size)
1448 			err = got_ferror(outfile, GOT_ERR_IO);
1449 	}
1450 	rewind(outfile);
1451 	if (err == NULL)
1452 		*result_size = accum_size;
1453 	return err;
1454 }
1455 
1456 const struct got_error *
1457 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1458     struct got_delta_chain *deltas, struct got_pack *pack)
1459 {
1460 	const struct got_error *err = NULL;
1461 	struct got_delta *delta;
1462 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1463 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1464 	uint64_t max_size = 0;
1465 	int n = 0;
1466 
1467 	*outbuf = NULL;
1468 	*outlen = 0;
1469 
1470 	if (STAILQ_EMPTY(&deltas->entries))
1471 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1472 
1473 	/* Deltas are ordered in ascending order. */
1474 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1475 		uint64_t base_size, result_size = 0;
1476 		int cached = 1;
1477 		if (n == 0) {
1478 			size_t delta_data_offset;
1479 
1480 			/* Plain object types are the delta base. */
1481 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1482 			    delta->type != GOT_OBJ_TYPE_TREE &&
1483 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1484 			    delta->type != GOT_OBJ_TYPE_TAG) {
1485 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1486 				goto done;
1487 			}
1488 
1489 			delta_data_offset = delta->offset + delta->tslen;
1490 			if (delta_data_offset >= pack->filesize) {
1491 				err = got_error(GOT_ERR_PACK_OFFSET);
1492 				goto done;
1493 			}
1494 
1495 			if (delta->size > max_size)
1496 				max_size = delta->size;
1497 
1498 			if (pack->map) {
1499 				size_t mapoff = (size_t)delta_data_offset;
1500 				err = got_inflate_to_mem_mmap(&base_buf,
1501 				    &base_bufsz, NULL, NULL, pack->map,
1502 				    mapoff, pack->filesize - mapoff);
1503 			} else {
1504 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1505 				    == -1) {
1506 					err = got_error_from_errno("lseek");
1507 					goto done;
1508 				}
1509 				err = got_inflate_to_mem_fd(&base_buf,
1510 				    &base_bufsz, NULL, NULL, max_size,
1511 				    pack->fd);
1512 			}
1513 			if (err)
1514 				goto done;
1515 			n++;
1516 			continue;
1517 		}
1518 
1519 		got_delta_cache_get(&delta_buf, &delta_len,
1520 		    pack->delta_cache, delta->data_offset);
1521 		if (delta_buf == NULL) {
1522 			cached = 0;
1523 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1524 			    delta->data_offset, pack);
1525 			if (err)
1526 				goto done;
1527 			err = got_delta_cache_add(pack->delta_cache,
1528 			    delta->data_offset, delta_buf, delta_len);
1529 			if (err == NULL)
1530 				cached = 1;
1531 			else if (err->code != GOT_ERR_NO_SPACE) {
1532 				free(delta_buf);
1533 				goto done;
1534 			}
1535 		}
1536 
1537 		err = got_delta_get_sizes(&base_size, &result_size,
1538 		    delta_buf, delta_len);
1539 		if (err)
1540 			goto done;
1541 		if (base_size > max_size)
1542 			max_size = base_size;
1543 		if (result_size > max_size)
1544 			max_size = result_size;
1545 
1546 		if (max_size > base_bufsz) {
1547 			uint8_t *p = realloc(base_buf, max_size);
1548 			if (p == NULL) {
1549 				err = got_error_from_errno("realloc");
1550 				goto done;
1551 			}
1552 			base_buf = p;
1553 			base_bufsz = max_size;
1554 		}
1555 
1556 		if (max_size > accum_bufsz) {
1557 			uint8_t *p = realloc(accum_buf, max_size);
1558 			if (p == NULL) {
1559 				err = got_error_from_errno("realloc");
1560 				goto done;
1561 			}
1562 			accum_buf = p;
1563 			accum_bufsz = max_size;
1564 		}
1565 
1566 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1567 		    delta_buf, delta_len, accum_buf,
1568 		    &accum_size, max_size);
1569 		if (!cached)
1570 			free(delta_buf);
1571 		n++;
1572 		if (err)
1573 			goto done;
1574 
1575 		if (n < deltas->nentries) {
1576 			/* Accumulated delta becomes the new base. */
1577 			uint8_t *tmp = accum_buf;
1578 			size_t tmp_size = accum_bufsz;
1579 			accum_buf = base_buf;
1580 			accum_bufsz = base_bufsz;
1581 			base_buf = tmp;
1582 			base_bufsz = tmp_size;
1583 		}
1584 	}
1585 
1586 done:
1587 	free(base_buf);
1588 	if (err) {
1589 		free(accum_buf);
1590 		*outbuf = NULL;
1591 		*outlen = 0;
1592 	} else {
1593 		*outbuf = accum_buf;
1594 		*outlen = accum_size;
1595 	}
1596 	return err;
1597 }
1598 
1599 const struct got_error *
1600 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1601     FILE *outfile, FILE *base_file, FILE *accum_file)
1602 {
1603 	const struct got_error *err = NULL;
1604 
1605 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1606 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1607 
1608 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1609 		if (obj->pack_offset >= pack->filesize)
1610 			return got_error(GOT_ERR_PACK_OFFSET);
1611 
1612 		if (pack->map) {
1613 			size_t mapoff = (size_t)obj->pack_offset;
1614 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1615 			    pack->map, mapoff, pack->filesize - mapoff,
1616 			    outfile);
1617 		} else {
1618 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1619 				return got_error_from_errno("lseek");
1620 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1621 			    pack->fd, outfile);
1622 		}
1623 	} else
1624 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1625 		    &obj->deltas, pack, outfile, base_file, accum_file);
1626 
1627 	return err;
1628 }
1629 
1630 const struct got_error *
1631 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1632     struct got_object *obj, struct got_pack *pack)
1633 {
1634 	const struct got_error *err = NULL;
1635 
1636 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1637 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1638 
1639 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1640 		if (obj->pack_offset >= pack->filesize)
1641 			return got_error(GOT_ERR_PACK_OFFSET);
1642 		if (pack->map) {
1643 			size_t mapoff = (size_t)obj->pack_offset;
1644 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1645 			    pack->map, mapoff, pack->filesize - mapoff);
1646 		} else {
1647 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1648 				return got_error_from_errno("lseek");
1649 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1650 			    obj->size, pack->fd);
1651 		}
1652 	} else
1653 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1654 		    pack);
1655 
1656 	return err;
1657 }
1658 
1659 static const struct got_error *
1660 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1661     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1662     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1663 {
1664 	const struct got_error *err = NULL;
1665 
1666 	/* Validate decompression and obtain the decompressed size. */
1667 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1668 	    delta_data_offset, pack);
1669 	if (err)
1670 		return err;
1671 
1672 	/* Read delta base/result sizes from head of delta stream. */
1673 	err = got_delta_get_sizes(base_size, result_size,
1674 	    *delta_buf, *delta_len);
1675 	if (err)
1676 		goto done;
1677 
1678 	/* Discard decompressed delta and read it again in compressed form. */
1679 	free(*delta_buf);
1680 	*delta_buf = malloc(*delta_len_compressed);
1681 	if (*delta_buf == NULL) {
1682 		err = got_error_from_errno("malloc");
1683 		goto done;
1684 	}
1685 	if (pack->map) {
1686 		if (delta_data_offset >= pack->filesize)
1687 			err = got_error(GOT_ERR_PACK_OFFSET);
1688 		memcpy(*delta_buf, pack->map + delta_data_offset,
1689 		    *delta_len_compressed);
1690 	} else {
1691 		ssize_t n;
1692 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1693 			err = got_error_from_errno("lseek");
1694 			goto done;
1695 		}
1696 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1697 		if (n < 0) {
1698 			err = got_error_from_errno("read");
1699 			goto done;
1700 		} else if (n != *delta_len_compressed) {
1701 			err = got_error(GOT_ERR_IO);
1702 			goto done;
1703 		}
1704 	}
1705 done:
1706 	if (err) {
1707 		free(*delta_buf);
1708 		*delta_buf = NULL;
1709 		*delta_len = 0;
1710 		*delta_len_compressed = 0;
1711 		*base_size = 0;
1712 		*result_size = 0;
1713 	}
1714 	return err;
1715 }
1716 
1717 const struct got_error *
1718 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1719     size_t *delta_compressed_size, off_t *delta_offset, off_t *base_offset,
1720     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1721     struct got_pack *pack, struct got_packidx *packidx, int idx)
1722 {
1723 	const struct got_error *err = NULL;
1724 	off_t offset;
1725 	uint8_t type;
1726 	uint64_t size;
1727 	size_t tslen, delta_hdrlen;
1728 	off_t delta_data_offset;
1729 
1730 	*delta_buf = NULL;
1731 	*delta_size = 0;
1732 	*delta_compressed_size = 0;
1733 	*delta_offset = 0;
1734 	*base_offset = 0;
1735 	*base_size = 0;
1736 	*result_size = 0;
1737 
1738 	offset = got_packidx_get_object_offset(packidx, idx);
1739 	if (offset == (uint64_t)-1)
1740 		return got_error(GOT_ERR_BAD_PACKIDX);
1741 
1742 	if (offset >= pack->filesize)
1743 		return got_error(GOT_ERR_PACK_OFFSET);
1744 
1745 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1746 	    pack, offset);
1747 	if (err)
1748 		return err;
1749 
1750 	if (tslen + size < tslen || offset + size < size ||
1751 	    tslen + offset < tslen)
1752 		return got_error(GOT_ERR_PACK_OFFSET);
1753 
1754 	switch (type) {
1755 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1756 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1757 		    pack, offset, tslen);
1758 		if (err)
1759 			return err;
1760 		break;
1761 	case GOT_OBJ_TYPE_REF_DELTA:
1762 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1763 		if (err)
1764 			return err;
1765 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1766 		break;
1767 	default:
1768 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1769 		    "non-delta object type %d found at offset %llu",
1770 		    type, offset);
1771 	}
1772 
1773 	if (tslen + delta_hdrlen < delta_hdrlen ||
1774 	    offset + delta_hdrlen < delta_hdrlen)
1775 		return got_error(GOT_ERR_BAD_DELTA);
1776 
1777 	delta_data_offset = offset + tslen + delta_hdrlen;
1778 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
1779 	    base_size, result_size, delta_data_offset, pack, packidx);
1780 	if (err)
1781 		return err;
1782 
1783 	if (*delta_size != size) {
1784 		err = got_error(GOT_ERR_BAD_DELTA);
1785 		goto done;
1786 	}
1787 
1788 	*delta_offset = offset;
1789 done:
1790 	if (err) {
1791 		free(*delta_buf);
1792 		*delta_buf = NULL;
1793 		*delta_size = 0;
1794 		*delta_compressed_size = 0;
1795 		*delta_offset = 0;
1796 		*base_offset = 0;
1797 		*base_size = 0;
1798 		*result_size = 0;
1799 	}
1800 	return err;
1801 }