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 	return err;
751 }
752 
753 const struct got_error *
754 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
755     struct got_pack *pack, off_t offset)
756 {
757 	uint8_t t = 0;
758 	uint64_t s = 0;
759 	uint8_t sizeN;
760 	size_t mapoff = 0;
761 	int i = 0;
762 
763 	*len = 0;
764 
765 	if (offset >= pack->filesize)
766 		return got_error(GOT_ERR_PACK_OFFSET);
767 
768 	if (pack->map) {
769 		mapoff = (size_t)offset;
770 	} else {
771 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
772 			return got_error_from_errno("lseek");
773 	}
774 
775 	do {
776 		/* We do not support size values which don't fit in 64 bit. */
777 		if (i > 9)
778 			return got_error(GOT_ERR_NO_SPACE);
779 
780 		if (pack->map) {
781 			if (mapoff + sizeof(sizeN) >= pack->filesize)
782 				return got_error(GOT_ERR_BAD_PACKFILE);
783 			sizeN = *(pack->map + mapoff);
784 			mapoff += sizeof(sizeN);
785 		} else {
786 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
787 			if (n < 0)
788 				return got_error_from_errno("read");
789 			if (n != sizeof(sizeN))
790 				return got_error(GOT_ERR_BAD_PACKFILE);
791 		}
792 		*len += sizeof(sizeN);
793 
794 		if (i == 0) {
795 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
796 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
797 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
798 		} else {
799 			size_t shift = 4 + 7 * (i - 1);
800 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
801 		}
802 		i++;
803 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
804 
805 	*type = t;
806 	*size = s;
807 	return NULL;
808 }
809 
810 static const struct got_error *
811 open_plain_object(struct got_object **obj, struct got_object_id *id,
812     uint8_t type, off_t offset, size_t size, int idx)
813 {
814 	*obj = calloc(1, sizeof(**obj));
815 	if (*obj == NULL)
816 		return got_error_from_errno("calloc");
817 
818 	(*obj)->type = type;
819 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
820 	(*obj)->pack_idx = idx;
821 	(*obj)->hdrlen = 0;
822 	(*obj)->size = size;
823 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
824 	(*obj)->pack_offset = offset;
825 
826 	return NULL;
827 }
828 
829 static const struct got_error *
830 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
831     off_t delta_offset)
832 {
833 	int64_t o = 0;
834 	uint8_t offN;
835 	int i = 0;
836 
837 	*offset = 0;
838 	*len = 0;
839 
840 	do {
841 		/* We do not support offset values which don't fit in 64 bit. */
842 		if (i > 8)
843 			return got_error(GOT_ERR_NO_SPACE);
844 
845 		if (pack->map) {
846 			size_t mapoff;
847 			mapoff = (size_t)delta_offset + *len;
848 			if (mapoff + sizeof(offN) >= pack->filesize)
849 				return got_error(GOT_ERR_PACK_OFFSET);
850 			offN = *(pack->map + mapoff);
851 		} else {
852 			ssize_t n;
853 			n = read(pack->fd, &offN, sizeof(offN));
854 			if (n < 0)
855 				return got_error_from_errno("read");
856 			if (n != sizeof(offN))
857 				return got_error(GOT_ERR_BAD_PACKFILE);
858 		}
859 		*len += sizeof(offN);
860 
861 		if (i == 0)
862 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
863 		else {
864 			o++;
865 			o <<= 7;
866 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
867 		}
868 		i++;
869 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
870 
871 	*offset = o;
872 	return NULL;
873 }
874 
875 const struct got_error *
876 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
877     struct got_pack *pack, off_t offset, int tslen)
878 {
879 	const struct got_error *err;
880 	int64_t negoffset;
881 	size_t negofflen;
882 
883 	*len = 0;
884 
885 	err = parse_negative_offset(&negoffset, &negofflen, pack,
886 	    offset + tslen);
887 	if (err)
888 		return err;
889 
890 	/* Compute the base object's offset (must be in the same pack file). */
891 	*base_offset = (offset - negoffset);
892 	if (*base_offset <= 0)
893 		return got_error(GOT_ERR_BAD_PACKFILE);
894 
895 	*len = negofflen;
896 	return NULL;
897 }
898 
899 static const struct got_error *
900 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
901     size_t *delta_compressed_len, size_t delta_data_offset,
902     struct got_pack *pack)
903 {
904 	const struct got_error *err = NULL;
905 	size_t consumed = 0;
906 
907 	if (pack->map) {
908 		if (delta_data_offset >= pack->filesize)
909 			return got_error(GOT_ERR_PACK_OFFSET);
910 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
911 		    &consumed, NULL, pack->map, delta_data_offset,
912 		    pack->filesize - delta_data_offset);
913 		if (err)
914 			return err;
915 	} else {
916 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
917 			return got_error_from_errno("lseek");
918 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
919 		    &consumed, NULL, 0, pack->fd);
920 		if (err)
921 			return err;
922 	}
923 
924 	if (delta_compressed_len)
925 		*delta_compressed_len = consumed;
926 
927 	return NULL;
928 }
929 
930 static const struct got_error *
931 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
932     int delta_type, size_t delta_size, size_t delta_data_offset)
933 {
934 	struct got_delta *delta;
935 
936 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
937 	    delta_data_offset);
938 	if (delta == NULL)
939 		return got_error_from_errno("got_delta_open");
940 	/* delta is freed in got_object_close() */
941 	deltas->nentries++;
942 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
943 	return NULL;
944 }
945 
946 static const struct got_error *
947 resolve_offset_delta(struct got_delta_chain *deltas,
948     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
949     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
950 
951 {
952 	const struct got_error *err;
953 	off_t base_offset;
954 	uint8_t base_type;
955 	uint64_t base_size;
956 	size_t base_tslen;
957 	off_t delta_data_offset;
958 	size_t consumed;
959 
960 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
961 	    delta_offset, tslen);
962 	if (err)
963 		return err;
964 
965 	delta_data_offset = delta_offset + tslen + consumed;
966 	if (delta_data_offset >= pack->filesize)
967 		return got_error(GOT_ERR_PACK_OFFSET);
968 
969 	if (pack->map == NULL) {
970 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
971 		if (delta_data_offset == -1)
972 			return got_error_from_errno("lseek");
973 	}
974 
975 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
976 	    delta_data_offset);
977 	if (err)
978 		return err;
979 
980 	/* An offset delta must be in the same packfile. */
981 	if (base_offset >= pack->filesize)
982 		return got_error(GOT_ERR_PACK_OFFSET);
983 
984 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
985 	    &base_tslen, pack, base_offset);
986 	if (err)
987 		return err;
988 
989 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
990 	    base_tslen, base_type, base_size, recursion - 1);
991 }
992 
993 const struct got_error *
994 got_pack_parse_ref_delta(struct got_object_id *id,
995     struct got_pack *pack, off_t delta_offset, int tslen)
996 {
997 	if (pack->map) {
998 		size_t mapoff = delta_offset + tslen;
999 		if (mapoff + sizeof(*id) >= pack->filesize)
1000 			return got_error(GOT_ERR_PACK_OFFSET);
1001 		memcpy(id, pack->map + mapoff, sizeof(*id));
1002 	} else {
1003 		ssize_t n;
1004 		n = read(pack->fd, id, sizeof(*id));
1005 		if (n < 0)
1006 			return got_error_from_errno("read");
1007 		if (n != sizeof(*id))
1008 			return got_error(GOT_ERR_BAD_PACKFILE);
1009 	}
1010 
1011 	return NULL;
1012 }
1013 
1014 static const struct got_error *
1015 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1016     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1017     size_t delta_size, unsigned int recursion)
1018 {
1019 	const struct got_error *err;
1020 	struct got_object_id id;
1021 	int idx;
1022 	off_t base_offset;
1023 	uint8_t base_type;
1024 	uint64_t base_size;
1025 	size_t base_tslen;
1026 	off_t delta_data_offset;
1027 
1028 	if (delta_offset + tslen >= pack->filesize)
1029 		return got_error(GOT_ERR_PACK_OFFSET);
1030 
1031 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1032 	if (err)
1033 		return err;
1034 	if (pack->map) {
1035 		delta_data_offset = delta_offset + tslen + sizeof(id);
1036 	} else {
1037 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1038 		if (delta_data_offset == -1)
1039 			return got_error_from_errno("lseek");
1040 	}
1041 
1042 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1043 	    delta_data_offset);
1044 	if (err)
1045 		return err;
1046 
1047 	/* Delta base must be in the same pack file. */
1048 	idx = got_packidx_get_object_idx(packidx, &id);
1049 	if (idx == -1)
1050 		return got_error(GOT_ERR_NO_OBJ);
1051 
1052 	base_offset = got_packidx_get_object_offset(packidx, idx);
1053 	if (base_offset == (uint64_t)-1)
1054 		return got_error(GOT_ERR_BAD_PACKIDX);
1055 
1056 	if (base_offset >= pack->filesize)
1057 		return got_error(GOT_ERR_PACK_OFFSET);
1058 
1059 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1060 	    &base_tslen, pack, base_offset);
1061 	if (err)
1062 		return err;
1063 
1064 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1065 	    base_tslen, base_type, base_size, recursion - 1);
1066 }
1067 
1068 const struct got_error *
1069 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1070     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1071     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1072 {
1073 	const struct got_error *err = NULL;
1074 
1075 	if (--recursion == 0)
1076 		return got_error(GOT_ERR_RECURSION);
1077 
1078 	switch (delta_type) {
1079 	case GOT_OBJ_TYPE_COMMIT:
1080 	case GOT_OBJ_TYPE_TREE:
1081 	case GOT_OBJ_TYPE_BLOB:
1082 	case GOT_OBJ_TYPE_TAG:
1083 		/* Plain types are the final delta base. Recursion ends. */
1084 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1085 		    delta_size, 0);
1086 		break;
1087 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1088 		err = resolve_offset_delta(deltas, packidx, pack,
1089 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1090 		break;
1091 	case GOT_OBJ_TYPE_REF_DELTA:
1092 		err = resolve_ref_delta(deltas, packidx, pack,
1093 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1094 		break;
1095 	default:
1096 		return got_error(GOT_ERR_OBJ_TYPE);
1097 	}
1098 
1099 	return err;
1100 }
1101 
1102 static const struct got_error *
1103 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1104     struct got_pack *pack, struct got_object_id *id, off_t offset,
1105     size_t tslen, int delta_type, size_t delta_size, int idx)
1106 {
1107 	const struct got_error *err = NULL;
1108 	int resolved_type;
1109 
1110 	*obj = calloc(1, sizeof(**obj));
1111 	if (*obj == NULL)
1112 		return got_error_from_errno("calloc");
1113 
1114 	(*obj)->flags = 0;
1115 	(*obj)->hdrlen = 0;
1116 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1117 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1118 	(*obj)->pack_offset = offset + tslen;
1119 
1120 	STAILQ_INIT(&(*obj)->deltas.entries);
1121 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1122 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1123 	(*obj)->pack_idx = idx;
1124 
1125 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1126 	    offset, tslen, delta_type, delta_size,
1127 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1128 	if (err)
1129 		goto done;
1130 
1131 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1132 	if (err)
1133 		goto done;
1134 	(*obj)->type = resolved_type;
1135 done:
1136 	if (err) {
1137 		got_object_close(*obj);
1138 		*obj = NULL;
1139 	}
1140 	return err;
1141 }
1142 
1143 const struct got_error *
1144 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1145     struct got_packidx *packidx, int idx, struct got_object_id *id)
1146 {
1147 	const struct got_error *err = NULL;
1148 	off_t offset;
1149 	uint8_t type;
1150 	uint64_t size;
1151 	size_t tslen;
1152 
1153 	*obj = NULL;
1154 
1155 	offset = got_packidx_get_object_offset(packidx, idx);
1156 	if (offset == (uint64_t)-1)
1157 		return got_error(GOT_ERR_BAD_PACKIDX);
1158 
1159 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1160 	    pack, offset);
1161 	if (err)
1162 		return err;
1163 
1164 	switch (type) {
1165 	case GOT_OBJ_TYPE_COMMIT:
1166 	case GOT_OBJ_TYPE_TREE:
1167 	case GOT_OBJ_TYPE_BLOB:
1168 	case GOT_OBJ_TYPE_TAG:
1169 		err = open_plain_object(obj, id, type, offset + tslen,
1170 		    size, idx);
1171 		break;
1172 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1173 	case GOT_OBJ_TYPE_REF_DELTA:
1174 		err = open_delta_object(obj, packidx, pack, id, offset,
1175 		    tslen, type, size, idx);
1176 		break;
1177 	default:
1178 		err = got_error(GOT_ERR_OBJ_TYPE);
1179 		break;
1180 	}
1181 
1182 	return err;
1183 }
1184 
1185 const struct got_error *
1186 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1187     struct got_delta_chain *deltas, struct got_pack *pack)
1188 {
1189 	struct got_delta *delta;
1190 	uint64_t base_size = 0, result_size = 0;
1191 
1192 	*max_size = 0;
1193 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1194 		/* Plain object types are the delta base. */
1195 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1196 		    delta->type != GOT_OBJ_TYPE_TREE &&
1197 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1198 		    delta->type != GOT_OBJ_TYPE_TAG) {
1199 			const struct got_error *err;
1200 			uint8_t *delta_buf;
1201 			size_t delta_len;
1202 			int cached = 1;
1203 
1204 			got_delta_cache_get(&delta_buf, &delta_len,
1205 			    pack->delta_cache, delta->data_offset);
1206 			if (delta_buf == NULL) {
1207 				cached = 0;
1208 				err = read_delta_data(&delta_buf, &delta_len,
1209 				    NULL, delta->data_offset, pack);
1210 				if (err)
1211 					return err;
1212 				err = got_delta_cache_add(pack->delta_cache,
1213 				    delta->data_offset, delta_buf, delta_len);
1214 				if (err == NULL)
1215 					cached = 1;
1216 				else if (err->code != GOT_ERR_NO_SPACE) {
1217 					free(delta_buf);
1218 					return err;
1219 				}
1220 			}
1221 			err = got_delta_get_sizes(&base_size, &result_size,
1222 			    delta_buf, delta_len);
1223 			if (!cached)
1224 				free(delta_buf);
1225 			if (err)
1226 				return err;
1227 		} else
1228 			base_size = delta->size;
1229 		if (base_size > *max_size)
1230 			*max_size = base_size;
1231 		if (result_size > *max_size)
1232 			*max_size = result_size;
1233 	}
1234 
1235 	return NULL;
1236 }
1237 
1238 const struct got_error *
1239 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1240     struct got_pack *pack)
1241 {
1242 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1243 		return got_error(GOT_ERR_OBJ_TYPE);
1244 
1245 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1246 }
1247 
1248 const struct got_error *
1249 got_pack_dump_delta_chain_to_file(size_t *result_size,
1250     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1251     FILE *base_file, FILE *accum_file)
1252 {
1253 	const struct got_error *err = NULL;
1254 	struct got_delta *delta;
1255 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1256 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1257 	uint64_t max_size;
1258 	int n = 0;
1259 
1260 	*result_size = 0;
1261 
1262 	if (STAILQ_EMPTY(&deltas->entries))
1263 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1264 
1265 	/* We process small enough files entirely in memory for speed. */
1266 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1267 	if (err)
1268 		return err;
1269 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1270 		accum_buf = malloc(max_size);
1271 		if (accum_buf == NULL)
1272 			return got_error_from_errno("malloc");
1273 		base_file = NULL;
1274 		accum_file = NULL;
1275 	} else {
1276 		if (fseeko(base_file, 0L, SEEK_SET) == -1)
1277 			return got_error_from_errno("fseeko");
1278 		if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1279 			return got_error_from_errno("fseeko");
1280 	}
1281 
1282 	/* Deltas are ordered in ascending order. */
1283 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1284 		int cached = 1;
1285 		if (n == 0) {
1286 			size_t mapoff;
1287 			off_t delta_data_offset;
1288 
1289 			/* Plain object types are the delta base. */
1290 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1291 			    delta->type != GOT_OBJ_TYPE_TREE &&
1292 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1293 			    delta->type != GOT_OBJ_TYPE_TAG) {
1294 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1295 				goto done;
1296 			}
1297 
1298 			delta_data_offset = delta->offset + delta->tslen;
1299 			if (delta_data_offset >= pack->filesize) {
1300 				err = got_error(GOT_ERR_PACK_OFFSET);
1301 				goto done;
1302 			}
1303 			if (pack->map == NULL) {
1304 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1305 				    == -1) {
1306 					err = got_error_from_errno("lseek");
1307 					goto done;
1308 				}
1309 			}
1310 			if (base_file) {
1311 				if (pack->map) {
1312 					mapoff = (size_t)delta_data_offset;
1313 					err = got_inflate_to_file_mmap(
1314 					    &base_bufsz, NULL, NULL, pack->map,
1315 					    mapoff, pack->filesize - mapoff,
1316 					    base_file);
1317 				} else
1318 					err = got_inflate_to_file_fd(
1319 					    &base_bufsz, NULL, NULL, pack->fd,
1320 					    base_file);
1321 			} else {
1322 				if (pack->map) {
1323 					mapoff = (size_t)delta_data_offset;
1324 					err = got_inflate_to_mem_mmap(&base_buf,
1325 					    &base_bufsz, NULL, NULL,
1326 					    pack->map, mapoff,
1327 					    pack->filesize - mapoff);
1328 				} else
1329 					err = got_inflate_to_mem_fd(&base_buf,
1330 					    &base_bufsz, NULL, NULL, max_size,
1331 					    pack->fd);
1332 			}
1333 			if (err)
1334 				goto done;
1335 			n++;
1336 			if (base_file)
1337 				rewind(base_file);
1338 			continue;
1339 		}
1340 
1341 		got_delta_cache_get(&delta_buf, &delta_len,
1342 		    pack->delta_cache, delta->data_offset);
1343 		if (delta_buf == NULL) {
1344 			cached = 0;
1345 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1346 			    delta->data_offset, pack);
1347 			if (err)
1348 				goto done;
1349 			err = got_delta_cache_add(pack->delta_cache,
1350 			    delta->data_offset, delta_buf, delta_len);
1351 			if (err == NULL)
1352 				cached = 1;
1353 			else if (err->code != GOT_ERR_NO_SPACE) {
1354 				free(delta_buf);
1355 				goto done;
1356 			}
1357 		}
1358 		if (base_buf) {
1359 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1360 			    delta_buf, delta_len, accum_buf,
1361 			    &accum_size, max_size);
1362 			n++;
1363 		} else {
1364 			err = got_delta_apply(base_file, delta_buf,
1365 			    delta_len,
1366 			    /* Final delta application writes to output file. */
1367 			    ++n < deltas->nentries ? accum_file : outfile,
1368 			    &accum_size);
1369 		}
1370 		if (!cached)
1371 			free(delta_buf);
1372 		if (err)
1373 			goto done;
1374 
1375 		if (n < deltas->nentries) {
1376 			/* Accumulated delta becomes the new base. */
1377 			if (base_buf) {
1378 				uint8_t *tmp = accum_buf;
1379 				/*
1380 				 * Base buffer switches roles with accumulation
1381 				 * buffer. Ensure it can hold the largest
1382 				 * result in the delta chain. The initial
1383 				 * allocation might have been smaller.
1384 				 */
1385 				if (base_bufsz < max_size) {
1386 					uint8_t *p;
1387 					p = reallocarray(base_buf, 1, max_size);
1388 					if (p == NULL) {
1389 						err = got_error_from_errno(
1390 						    "reallocarray");
1391 						goto done;
1392 					}
1393 					base_buf = p;
1394 					base_bufsz = max_size;
1395 				}
1396 				accum_buf = base_buf;
1397 				base_buf = tmp;
1398 			} else {
1399 				FILE *tmp = accum_file;
1400 				accum_file = base_file;
1401 				base_file = tmp;
1402 				rewind(base_file);
1403 				rewind(accum_file);
1404 			}
1405 		}
1406 	}
1407 
1408 done:
1409 	free(base_buf);
1410 	if (accum_buf) {
1411 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1412 		free(accum_buf);
1413 		if (len != accum_size)
1414 			err = got_ferror(outfile, GOT_ERR_IO);
1415 	}
1416 	rewind(outfile);
1417 	if (err == NULL)
1418 		*result_size = accum_size;
1419 	return err;
1420 }
1421 
1422 const struct got_error *
1423 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1424     struct got_delta_chain *deltas, struct got_pack *pack)
1425 {
1426 	const struct got_error *err = NULL;
1427 	struct got_delta *delta;
1428 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1429 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1430 	uint64_t max_size;
1431 	int n = 0;
1432 
1433 	*outbuf = NULL;
1434 	*outlen = 0;
1435 
1436 	if (STAILQ_EMPTY(&deltas->entries))
1437 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1438 
1439 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1440 	if (err)
1441 		return err;
1442 	accum_buf = malloc(max_size);
1443 	if (accum_buf == NULL)
1444 		return got_error_from_errno("malloc");
1445 
1446 	/* Deltas are ordered in ascending order. */
1447 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1448 		int cached = 1;
1449 		if (n == 0) {
1450 			size_t delta_data_offset;
1451 
1452 			/* Plain object types are the delta base. */
1453 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1454 			    delta->type != GOT_OBJ_TYPE_TREE &&
1455 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1456 			    delta->type != GOT_OBJ_TYPE_TAG) {
1457 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1458 				goto done;
1459 			}
1460 
1461 			delta_data_offset = delta->offset + delta->tslen;
1462 			if (delta_data_offset >= pack->filesize) {
1463 				err = got_error(GOT_ERR_PACK_OFFSET);
1464 				goto done;
1465 			}
1466 			if (pack->map) {
1467 				size_t mapoff = (size_t)delta_data_offset;
1468 				err = got_inflate_to_mem_mmap(&base_buf,
1469 				    &base_bufsz, NULL, NULL, pack->map,
1470 				    mapoff, pack->filesize - mapoff);
1471 			} else {
1472 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1473 				    == -1) {
1474 					err = got_error_from_errno("lseek");
1475 					goto done;
1476 				}
1477 				err = got_inflate_to_mem_fd(&base_buf,
1478 				    &base_bufsz, NULL, NULL, max_size,
1479 				    pack->fd);
1480 			}
1481 			if (err)
1482 				goto done;
1483 			n++;
1484 			continue;
1485 		}
1486 
1487 		got_delta_cache_get(&delta_buf, &delta_len,
1488 		    pack->delta_cache, delta->data_offset);
1489 		if (delta_buf == NULL) {
1490 			cached = 0;
1491 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1492 			    delta->data_offset, pack);
1493 			if (err)
1494 				goto done;
1495 			err = got_delta_cache_add(pack->delta_cache,
1496 			    delta->data_offset, delta_buf, delta_len);
1497 			if (err == NULL)
1498 				cached = 1;
1499 			else if (err->code != GOT_ERR_NO_SPACE) {
1500 				free(delta_buf);
1501 				goto done;
1502 			}
1503 		}
1504 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1505 		    delta_buf, delta_len, accum_buf,
1506 		    &accum_size, max_size);
1507 		if (!cached)
1508 			free(delta_buf);
1509 		n++;
1510 		if (err)
1511 			goto done;
1512 
1513 		if (n < deltas->nentries) {
1514 			/* Accumulated delta becomes the new base. */
1515 			uint8_t *tmp = accum_buf;
1516 			/*
1517 			 * Base buffer switches roles with accumulation buffer.
1518 			 * Ensure it can hold the largest result in the delta
1519 			 * chain. Initial allocation might have been smaller.
1520 			 */
1521 			if (base_bufsz < max_size) {
1522 				uint8_t *p;
1523 				p = reallocarray(base_buf, 1, max_size);
1524 				if (p == NULL) {
1525 					err = got_error_from_errno(
1526 					    "reallocarray");
1527 					goto done;
1528 				}
1529 				base_buf = p;
1530 				base_bufsz = max_size;
1531 			}
1532 			accum_buf = base_buf;
1533 			base_buf = tmp;
1534 		}
1535 	}
1536 
1537 done:
1538 	free(base_buf);
1539 	if (err) {
1540 		free(accum_buf);
1541 		*outbuf = NULL;
1542 		*outlen = 0;
1543 	} else {
1544 		*outbuf = accum_buf;
1545 		*outlen = accum_size;
1546 	}
1547 	return err;
1548 }
1549 
1550 const struct got_error *
1551 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1552     FILE *outfile, FILE *base_file, FILE *accum_file)
1553 {
1554 	const struct got_error *err = NULL;
1555 
1556 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1557 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1558 
1559 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1560 		if (obj->pack_offset >= pack->filesize)
1561 			return got_error(GOT_ERR_PACK_OFFSET);
1562 
1563 		if (pack->map) {
1564 			size_t mapoff = (size_t)obj->pack_offset;
1565 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1566 			    pack->map, mapoff, pack->filesize - mapoff,
1567 			    outfile);
1568 		} else {
1569 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1570 				return got_error_from_errno("lseek");
1571 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1572 			    pack->fd, outfile);
1573 		}
1574 	} else
1575 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1576 		    &obj->deltas, pack, outfile, base_file, accum_file);
1577 
1578 	return err;
1579 }
1580 
1581 const struct got_error *
1582 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1583     struct got_object *obj, struct got_pack *pack)
1584 {
1585 	const struct got_error *err = NULL;
1586 
1587 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1588 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1589 
1590 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1591 		if (obj->pack_offset >= pack->filesize)
1592 			return got_error(GOT_ERR_PACK_OFFSET);
1593 		if (pack->map) {
1594 			size_t mapoff = (size_t)obj->pack_offset;
1595 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1596 			    pack->map, mapoff, pack->filesize - mapoff);
1597 		} else {
1598 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1599 				return got_error_from_errno("lseek");
1600 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1601 			    obj->size, pack->fd);
1602 		}
1603 	} else
1604 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1605 		    pack);
1606 
1607 	return err;
1608 }
1609 
1610 static const struct got_error *
1611 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1612     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1613     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1614 {
1615 	const struct got_error *err = NULL;
1616 
1617 	/* Validate decompression and obtain the decompressed size. */
1618 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1619 	    delta_data_offset, pack);
1620 	if (err)
1621 		return err;
1622 
1623 	/* Read delta base/result sizes from head of delta stream. */
1624 	err = got_delta_get_sizes(base_size, result_size,
1625 	    *delta_buf, *delta_len);
1626 	if (err)
1627 		goto done;
1628 
1629 	/* Discard decompressed delta and read it again in compressed form. */
1630 	free(*delta_buf);
1631 	*delta_buf = malloc(*delta_len_compressed);
1632 	if (*delta_buf == NULL) {
1633 		err = got_error_from_errno("malloc");
1634 		goto done;
1635 	}
1636 	if (pack->map) {
1637 		if (delta_data_offset >= pack->filesize)
1638 			err = got_error(GOT_ERR_PACK_OFFSET);
1639 		memcpy(*delta_buf, pack->map + delta_data_offset,
1640 		    *delta_len_compressed);
1641 	} else {
1642 		ssize_t n;
1643 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1644 			err = got_error_from_errno("lseek");
1645 			goto done;
1646 		}
1647 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1648 		if (n < 0) {
1649 			err = got_error_from_errno("read");
1650 			goto done;
1651 		} else if (n != *delta_len_compressed) {
1652 			err = got_error(GOT_ERR_IO);
1653 			goto done;
1654 		}
1655 	}
1656 done:
1657 	if (err) {
1658 		free(*delta_buf);
1659 		*delta_buf = NULL;
1660 		*delta_len = 0;
1661 		*delta_len_compressed = 0;
1662 		*base_size = 0;
1663 		*result_size = 0;
1664 	}
1665 	return err;
1666 }
1667 
1668 const struct got_error *
1669 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1670     size_t *delta_compressed_size, off_t *delta_offset, off_t *base_offset,
1671     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1672     struct got_pack *pack, struct got_packidx *packidx, int idx)
1673 {
1674 	const struct got_error *err = NULL;
1675 	off_t offset;
1676 	uint8_t type;
1677 	uint64_t size;
1678 	size_t tslen, delta_hdrlen;
1679 	off_t delta_data_offset;
1680 
1681 	*delta_buf = NULL;
1682 	*delta_size = 0;
1683 	*delta_compressed_size = 0;
1684 	*delta_offset = 0;
1685 	*base_offset = 0;
1686 	*base_size = 0;
1687 	*result_size = 0;
1688 
1689 	offset = got_packidx_get_object_offset(packidx, idx);
1690 	if (offset == (uint64_t)-1)
1691 		return got_error(GOT_ERR_BAD_PACKIDX);
1692 
1693 	if (offset >= pack->filesize)
1694 		return got_error(GOT_ERR_PACK_OFFSET);
1695 
1696 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1697 	    pack, offset);
1698 	if (err)
1699 		return err;
1700 
1701 	if (tslen + size < tslen || offset + size < size ||
1702 	    tslen + offset < tslen)
1703 		return got_error(GOT_ERR_PACK_OFFSET);
1704 
1705 	switch (type) {
1706 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1707 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1708 		    pack, offset, tslen);
1709 		if (err)
1710 			return err;
1711 		break;
1712 	case GOT_OBJ_TYPE_REF_DELTA:
1713 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1714 		if (err)
1715 			return err;
1716 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1717 		break;
1718 	default:
1719 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1720 		    "non-delta object type %d found at offset %llu",
1721 		    type, offset);
1722 	}
1723 
1724 	if (tslen + delta_hdrlen < delta_hdrlen ||
1725 	    offset + delta_hdrlen < delta_hdrlen)
1726 		return got_error(GOT_ERR_BAD_DELTA);
1727 
1728 	delta_data_offset = offset + tslen + delta_hdrlen;
1729 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
1730 	    base_size, result_size, delta_data_offset, pack, packidx);
1731 	if (err)
1732 		return err;
1733 
1734 	if (*delta_size != size) {
1735 		err = got_error(GOT_ERR_BAD_DELTA);
1736 		goto done;
1737 	}
1738 
1739 	*delta_offset = offset;
1740 done:
1741 	if (err) {
1742 		free(*delta_buf);
1743 		*delta_buf = NULL;
1744 		*delta_size = 0;
1745 		*delta_compressed_size = 0;
1746 		*delta_offset = 0;
1747 		*base_offset = 0;
1748 		*base_size = 0;
1749 		*result_size = 0;
1750 	}
1751 	return err;
1752 }