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 #include <sys/resource.h>
22 #include <sys/socket.h>
23 
24 #include <fcntl.h>
25 #include <errno.h>
26 #include <stdio.h>
27 #include <stdint.h>
28 #include <stdlib.h>
29 #include <string.h>
30 #include <limits.h>
31 #include <unistd.h>
32 #include <zlib.h>
33 
34 #include "got_error.h"
35 #include "got_object.h"
36 #include "got_path.h"
37 
38 #include "got_lib_sha1.h"
39 #include "got_lib_delta.h"
40 #include "got_lib_delta_cache.h"
41 #include "got_lib_inflate.h"
42 #include "got_lib_object.h"
43 #include "got_lib_object_parse.h"
44 #include "got_lib_privsep.h"
45 #include "got_lib_pack.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #ifndef MIN
52 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
53 #endif
54 
55 static const struct got_error *
56 verify_fanout_table(uint32_t *fanout_table)
57 {
58 	int i;
59 
60 	for (i = 0; i < 0xff - 1; i++) {
61 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
62 			return got_error(GOT_ERR_BAD_PACKIDX);
63 	}
64 
65 	return NULL;
66 }
67 
68 const struct got_error *
69 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
70 {
71 	const struct got_error *err = NULL;
72 	struct got_packidx_v2_hdr *h;
73 	SHA1_CTX ctx;
74 	uint8_t sha1[SHA1_DIGEST_LENGTH];
75 	size_t nobj, len_fanout, len_ids, offset, remain;
76 	ssize_t n;
77 	int i;
78 
79 	SHA1Init(&ctx);
80 
81 	h = &p->hdr;
82 	offset = 0;
83 	remain = p->len;
84 
85 	if (remain < sizeof(*h->magic)) {
86 		err = got_error(GOT_ERR_BAD_PACKIDX);
87 		goto done;
88 	}
89 	if (p->map)
90 		h->magic = (uint32_t *)(p->map + offset);
91 	else {
92 		h->magic = malloc(sizeof(*h->magic));
93 		if (h->magic == NULL) {
94 			err = got_error_from_errno("malloc");
95 			goto done;
96 		}
97 		n = read(p->fd, h->magic, sizeof(*h->magic));
98 		if (n < 0) {
99 			err = got_error_from_errno("read");
100 			goto done;
101 		} else if (n != sizeof(*h->magic)) {
102 			err = got_error(GOT_ERR_BAD_PACKIDX);
103 			goto done;
104 		}
105 	}
106 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
107 		err = got_error(GOT_ERR_BAD_PACKIDX);
108 		goto done;
109 	}
110 	offset += sizeof(*h->magic);
111 	remain -= sizeof(*h->magic);
112 
113 	if (verify)
114 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
115 
116 	if (remain < sizeof(*h->version)) {
117 		err = got_error(GOT_ERR_BAD_PACKIDX);
118 		goto done;
119 	}
120 	if (p->map)
121 		h->version = (uint32_t *)(p->map + offset);
122 	else {
123 		h->version = malloc(sizeof(*h->version));
124 		if (h->version == NULL) {
125 			err = got_error_from_errno("malloc");
126 			goto done;
127 		}
128 		n = read(p->fd, h->version, sizeof(*h->version));
129 		if (n < 0) {
130 			err = got_error_from_errno("read");
131 			goto done;
132 		} else if (n != sizeof(*h->version)) {
133 			err = got_error(GOT_ERR_BAD_PACKIDX);
134 			goto done;
135 		}
136 	}
137 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
138 		err = got_error(GOT_ERR_BAD_PACKIDX);
139 		goto done;
140 	}
141 	offset += sizeof(*h->version);
142 	remain -= sizeof(*h->version);
143 
144 	if (verify)
145 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
146 
147 	len_fanout =
148 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
149 	if (remain < len_fanout) {
150 		err = got_error(GOT_ERR_BAD_PACKIDX);
151 		goto done;
152 	}
153 	if (p->map)
154 		h->fanout_table = (uint32_t *)(p->map + offset);
155 	else {
156 		h->fanout_table = malloc(len_fanout);
157 		if (h->fanout_table == NULL) {
158 			err = got_error_from_errno("malloc");
159 			goto done;
160 		}
161 		n = read(p->fd, h->fanout_table, len_fanout);
162 		if (n < 0) {
163 			err = got_error_from_errno("read");
164 			goto done;
165 		} else if (n != len_fanout) {
166 			err = got_error(GOT_ERR_BAD_PACKIDX);
167 			goto done;
168 		}
169 	}
170 	err = verify_fanout_table(h->fanout_table);
171 	if (err)
172 		goto done;
173 	if (verify)
174 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
175 	offset += len_fanout;
176 	remain -= len_fanout;
177 
178 	nobj = be32toh(h->fanout_table[0xff]);
179 	len_ids = nobj * sizeof(*h->sorted_ids);
180 	if (len_ids <= nobj || len_ids > remain) {
181 		err = got_error(GOT_ERR_BAD_PACKIDX);
182 		goto done;
183 	}
184 	if (p->map)
185 		h->sorted_ids =
186 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
187 	else {
188 		h->sorted_ids = malloc(len_ids);
189 		if (h->sorted_ids == NULL) {
190 			err = got_error(GOT_ERR_BAD_PACKIDX);
191 			goto done;
192 		}
193 		n = read(p->fd, h->sorted_ids, len_ids);
194 		if (n < 0)
195 			err = got_error_from_errno("read");
196 		else if (n != len_ids) {
197 			err = got_error(GOT_ERR_BAD_PACKIDX);
198 			goto done;
199 		}
200 	}
201 	if (verify)
202 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
203 	offset += len_ids;
204 	remain -= len_ids;
205 
206 	if (remain < nobj * sizeof(*h->crc32)) {
207 		err = got_error(GOT_ERR_BAD_PACKIDX);
208 		goto done;
209 	}
210 	if (p->map)
211 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
212 	else {
213 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
214 		if (h->crc32 == NULL) {
215 			err = got_error_from_errno("malloc");
216 			goto done;
217 		}
218 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
219 		if (n < 0)
220 			err = got_error_from_errno("read");
221 		else if (n != nobj * sizeof(*h->crc32)) {
222 			err = got_error(GOT_ERR_BAD_PACKIDX);
223 			goto done;
224 		}
225 	}
226 	if (verify)
227 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
228 	remain -= nobj * sizeof(*h->crc32);
229 	offset += nobj * sizeof(*h->crc32);
230 
231 	if (remain < nobj * sizeof(*h->offsets)) {
232 		err = got_error(GOT_ERR_BAD_PACKIDX);
233 		goto done;
234 	}
235 	if (p->map)
236 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
237 	else {
238 		h->offsets = malloc(nobj * sizeof(*h->offsets));
239 		if (h->offsets == NULL) {
240 			err = got_error_from_errno("malloc");
241 			goto done;
242 		}
243 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
244 		if (n < 0)
245 			err = got_error_from_errno("read");
246 		else if (n != nobj * sizeof(*h->offsets)) {
247 			err = got_error(GOT_ERR_BAD_PACKIDX);
248 			goto done;
249 		}
250 	}
251 	if (verify)
252 		SHA1Update(&ctx, (uint8_t *)h->offsets,
253 		    nobj * sizeof(*h->offsets));
254 	remain -= nobj * sizeof(*h->offsets);
255 	offset += nobj * sizeof(*h->offsets);
256 
257 	/* Large file offsets are contained only in files > 2GB. */
258 	if (verify || packfile_size > 0x7fffffff) {
259 		for (i = 0; i < nobj; i++) {
260 			uint32_t o = h->offsets[i];
261 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
262 				p->nlargeobj++;
263 		}
264 	}
265 	if (p->nlargeobj == 0)
266 		goto checksum;
267 	else if (packfile_size <= 0x7fffffff) {
268 		err = got_error(GOT_ERR_BAD_PACKIDX);
269 		goto done;
270 	}
271 
272 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
273 		err = got_error(GOT_ERR_BAD_PACKIDX);
274 		goto done;
275 	}
276 	if (p->map)
277 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
278 	else {
279 		h->large_offsets = malloc(p->nlargeobj *
280 		    sizeof(*h->large_offsets));
281 		if (h->large_offsets == NULL) {
282 			err = got_error_from_errno("malloc");
283 			goto done;
284 		}
285 		n = read(p->fd, h->large_offsets,
286 		    p->nlargeobj * sizeof(*h->large_offsets));
287 		if (n < 0)
288 			err = got_error_from_errno("read");
289 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
290 			err = got_error(GOT_ERR_BAD_PACKIDX);
291 			goto done;
292 		}
293 	}
294 	if (verify)
295 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
296 		    p->nlargeobj * sizeof(*h->large_offsets));
297 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
298 	offset += p->nlargeobj * sizeof(*h->large_offsets);
299 
300 checksum:
301 	if (remain < sizeof(*h->trailer)) {
302 		err = got_error(GOT_ERR_BAD_PACKIDX);
303 		goto done;
304 	}
305 	if (p->map)
306 		h->trailer =
307 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
308 	else {
309 		h->trailer = malloc(sizeof(*h->trailer));
310 		if (h->trailer == NULL) {
311 			err = got_error_from_errno("malloc");
312 			goto done;
313 		}
314 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
315 		if (n < 0)
316 			err = got_error_from_errno("read");
317 		else if (n != sizeof(*h->trailer)) {
318 			err = got_error(GOT_ERR_BAD_PACKIDX);
319 			goto done;
320 		}
321 	}
322 	if (verify) {
323 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
324 		SHA1Final(sha1, &ctx);
325 		if (memcmp(h->trailer->packidx_sha1, sha1,
326 		    SHA1_DIGEST_LENGTH) != 0)
327 			err = got_error(GOT_ERR_PACKIDX_CSUM);
328 	}
329 done:
330 	return err;
331 }
332 
333 const struct got_error *
334 got_packidx_open(struct got_packidx **packidx,
335     int dir_fd, const char *relpath, int verify)
336 {
337 	const struct got_error *err = NULL;
338 	struct got_packidx *p = NULL;
339 	char *pack_relpath;
340 	struct stat idx_sb, pack_sb;
341 
342 	*packidx = NULL;
343 
344 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
345 	if (err)
346 		return err;
347 
348 	/*
349 	 * Ensure that a corresponding pack file exists.
350 	 * Some Git repositories have this problem. Git seems to ignore
351 	 * the existence of lonely pack index files but we do not.
352 	 */
353 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
354 		if (errno == ENOENT) {
355 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
356 			    "%s", relpath);
357 		} else
358 			err = got_error_from_errno2("fstatat", pack_relpath);
359 		goto done;
360 	}
361 
362 	p = calloc(1, sizeof(*p));
363 	if (p == NULL) {
364 		err = got_error_from_errno("calloc");
365 		goto done;
366 	}
367 
368 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
369 	if (p->fd == -1) {
370 		err = got_error_from_errno2("openat", relpath);
371 		goto done;
372 	}
373 
374 	if (fstat(p->fd, &idx_sb) != 0) {
375 		err = got_error_from_errno2("fstat", relpath);
376 		goto done;
377 	}
378 	p->len = idx_sb.st_size;
379 	if (p->len < sizeof(p->hdr)) {
380 		err = got_error(GOT_ERR_BAD_PACKIDX);
381 		goto done;
382 	}
383 
384 	p->path_packidx = strdup(relpath);
385 	if (p->path_packidx == NULL) {
386 		err = got_error_from_errno("strdup");
387 		goto done;
388 	}
389 
390 #ifndef GOT_PACK_NO_MMAP
391 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
392 	if (p->map == MAP_FAILED) {
393 		if (errno != ENOMEM) {
394 			err = got_error_from_errno("mmap");
395 			goto done;
396 		}
397 		p->map = NULL; /* fall back to read(2) */
398 	}
399 #endif
400 
401 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
402 done:
403 	if (err) {
404 		if (p)
405 			got_packidx_close(p);
406 	} else
407 		*packidx = p;
408 	free(pack_relpath);
409 	return err;
410 }
411 
412 const struct got_error *
413 got_packidx_close(struct got_packidx *packidx)
414 {
415 	const struct got_error *err = NULL;
416 
417 	free(packidx->path_packidx);
418 	if (packidx->map) {
419 		if (munmap(packidx->map, packidx->len) == -1)
420 			err = got_error_from_errno("munmap");
421 	} else {
422 		free(packidx->hdr.magic);
423 		free(packidx->hdr.version);
424 		free(packidx->hdr.fanout_table);
425 		free(packidx->hdr.sorted_ids);
426 		free(packidx->hdr.crc32);
427 		free(packidx->hdr.offsets);
428 		free(packidx->hdr.large_offsets);
429 		free(packidx->hdr.trailer);
430 	}
431 	if (close(packidx->fd) == -1 && err == NULL)
432 		err = got_error_from_errno("close");
433 	free(packidx->sorted_offsets);
434 	free(packidx->sorted_large_offsets);
435 	free(packidx);
436 
437 	return err;
438 }
439 
440 const struct got_error *
441 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
442 {
443 	size_t size;
444 
445 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
446 	size = strlen(path_packidx) + 2;
447 	if (size < GOT_PACKFILE_NAMELEN + 1)
448 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
449 
450 	*path_packfile = malloc(size);
451 	if (*path_packfile == NULL)
452 		return got_error_from_errno("malloc");
453 
454 	/* Copy up to and excluding ".idx". */
455 	if (strlcpy(*path_packfile, path_packidx,
456 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
457 		return got_error(GOT_ERR_NO_SPACE);
458 
459 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
460 		return got_error(GOT_ERR_NO_SPACE);
461 
462 	return NULL;
463 }
464 
465 off_t
466 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
467 {
468 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
469 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
470 		uint64_t loffset;
471 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
472 		if (idx < 0 || idx >= packidx->nlargeobj ||
473 		    packidx->hdr.large_offsets == NULL)
474 			return -1;
475 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
476 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
477 	}
478 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
479 }
480 
481 int
482 got_packidx_get_object_idx(struct got_packidx *packidx,
483     struct got_object_id *id)
484 {
485 	u_int8_t id0 = id->sha1[0];
486 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
487 	int left = 0, right = totobj - 1;
488 
489 	if (id0 > 0)
490 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
491 
492 	while (left <= right) {
493 		struct got_packidx_object_id *oid;
494 		int i, cmp;
495 
496 		i = ((left + right) / 2);
497 		oid = &packidx->hdr.sorted_ids[i];
498 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
499 		if (cmp == 0)
500 			return i;
501 		else if (cmp > 0)
502 			left = i + 1;
503 		else if (cmp < 0)
504 			right = i - 1;
505 	}
506 
507 	return -1;
508 }
509 
510 static int
511 offset_cmp(const void *pa, const void *pb)
512 {
513 	const struct got_pack_offset_index *a, *b;
514 
515 	a = (const struct got_pack_offset_index *)pa;
516 	b = (const struct got_pack_offset_index *)pb;
517 
518 	if (a->offset < b->offset)
519 		return -1;
520 	else if (a->offset > b->offset)
521 		return 1;
522 
523 	return 0;
524 }
525 
526 static int
527 large_offset_cmp(const void *pa, const void *pb)
528 {
529 	const struct got_pack_large_offset_index *a, *b;
530 
531 	a = (const struct got_pack_large_offset_index *)pa;
532 	b = (const struct got_pack_large_offset_index *)pb;
533 
534 	if (a->offset < b->offset)
535 		return -1;
536 	else if (a->offset > b->offset)
537 		return 1;
538 
539 	return 0;
540 }
541 
542 static const struct got_error *
543 build_offset_index(struct got_packidx *p)
544 {
545 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
546 	unsigned int i, j, k;
547 
548 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
549 	    sizeof(p->sorted_offsets[0]));
550 	if (p->sorted_offsets == NULL)
551 		return got_error_from_errno("calloc");
552 
553 	if (p->nlargeobj > 0) {
554 		p->sorted_large_offsets = calloc(p->nlargeobj,
555 		    sizeof(p->sorted_large_offsets[0]));
556 		if (p->sorted_large_offsets == NULL)
557 			return got_error_from_errno("calloc");
558 	}
559 
560 	j = 0;
561 	k = 0;
562 	for (i = 0; i < nobj; i++) {
563 		uint32_t offset = be32toh(p->hdr.offsets[i]);
564 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
565 			uint64_t loffset;
566 			uint32_t idx;
567 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
568 			if (idx >= p->nlargeobj ||
569 			    p->nlargeobj == 0 ||
570 			    p->hdr.large_offsets == NULL)
571 				return got_error(GOT_ERR_BAD_PACKIDX);
572 			loffset = be64toh(p->hdr.large_offsets[idx]);
573 			p->sorted_large_offsets[j].offset = loffset;
574 			p->sorted_large_offsets[j].idx = i;
575 			j++;
576 		} else {
577 			p->sorted_offsets[k].offset = offset;
578 			p->sorted_offsets[k].idx = i;
579 			k++;
580 		}
581 	}
582 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
583 		return got_error(GOT_ERR_BAD_PACKIDX);
584 
585 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
586 	    sizeof(p->sorted_offsets[0]), offset_cmp);
587 
588 	if (p->sorted_large_offsets)
589 		qsort(p->sorted_large_offsets, p->nlargeobj,
590 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
591 
592 	return NULL;
593 }
594 
595 const struct got_error *
596 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
597 {
598 	const struct got_error *err;
599 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
600 	int i, left, right;
601 
602 	*idx = -1;
603 
604 	if (packidx->sorted_offsets == NULL) {
605 		err = build_offset_index(packidx);
606 		if (err)
607 			return err;
608 	}
609 
610 	if (offset >= 0x7fffffff) {
611 		uint64_t lo;
612 		left = 0, right = packidx->nlargeobj - 1;
613 		while (left <= right) {
614 			i = ((left + right) / 2);
615 			lo = packidx->sorted_large_offsets[i].offset;
616 			if (lo == offset) {
617 				*idx = packidx->sorted_large_offsets[i].idx;
618 				break;
619 			} else if (offset > lo)
620 				left = i + 1;
621 			else if (offset < lo)
622 				right = i - 1;
623 		}
624 	} else {
625 		uint32_t o;
626 		left = 0, right = totobj - packidx->nlargeobj - 1;
627 		while (left <= right) {
628 			i = ((left + right) / 2);
629 			o = packidx->sorted_offsets[i].offset;
630 			if (o == offset) {
631 				*idx = packidx->sorted_offsets[i].idx;
632 				break;
633 			} else if (offset > o)
634 				left = i + 1;
635 			else if (offset < o)
636 				right = i - 1;
637 		}
638 	}
639 
640 	return NULL;
641 }
642 
643 const struct got_error *
644 got_packidx_get_object_id(struct got_object_id *id,
645     struct got_packidx *packidx, int idx)
646 {
647 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
648 	struct got_packidx_object_id *oid;
649 
650 	if (idx < 0 || idx >= totobj)
651 		return got_error(GOT_ERR_NO_OBJ);
652 
653 	oid = &packidx->hdr.sorted_ids[idx];
654 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
655 	return NULL;
656 }
657 
658 const struct got_error *
659 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
660     struct got_packidx *packidx, const char *id_str_prefix)
661 {
662 	const struct got_error *err = NULL;
663 	u_int8_t id0;
664 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
665 	char hex[3];
666 	size_t prefix_len = strlen(id_str_prefix);
667 	struct got_packidx_object_id *oid;
668 	uint32_t i = 0;
669 
670 	STAILQ_INIT(matched_ids);
671 
672 	if (prefix_len < 2)
673 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
674 
675 	hex[0] = id_str_prefix[0];
676 	hex[1] = id_str_prefix[1];
677 	hex[2] = '\0';
678 	if (!got_parse_xdigit(&id0, hex))
679 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
680 
681 	if (id0 > 0)
682 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
683 	oid = &packidx->hdr.sorted_ids[i];
684 	while (i < totobj && oid->sha1[0] == id0) {
685 		char id_str[SHA1_DIGEST_STRING_LENGTH];
686 		struct got_object_qid *qid;
687 		int cmp;
688 
689 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
690 		        return got_error(GOT_ERR_NO_SPACE);
691 
692 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
693 		if (cmp < 0) {
694 			oid = &packidx->hdr.sorted_ids[++i];
695 			continue;
696 		} else if (cmp > 0)
697 			break;
698 
699 		err = got_object_qid_alloc_partial(&qid);
700 		if (err)
701 			break;
702 		memcpy(qid->id.sha1, oid->sha1, SHA1_DIGEST_LENGTH);
703 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
704 
705 		oid = &packidx->hdr.sorted_ids[++i];
706 	}
707 
708 	if (err)
709 		got_object_id_queue_free(matched_ids);
710 	return err;
711 }
712 
713 static void
714 set_max_datasize(void)
715 {
716 	struct rlimit rl;
717 
718 	if (getrlimit(RLIMIT_DATA, &rl) != 0)
719 		return;
720 
721 	rl.rlim_cur = rl.rlim_max;
722 	setrlimit(RLIMIT_DATA, &rl);
723 }
724 
725 const struct got_error *
726 got_pack_start_privsep_child(struct got_pack *pack, struct got_packidx *packidx)
727 {
728 	const struct got_error *err = NULL;
729 	int imsg_fds[2];
730 	pid_t pid;
731 	struct imsgbuf *ibuf;
732 
733 	ibuf = calloc(1, sizeof(*ibuf));
734 	if (ibuf == NULL)
735 		return got_error_from_errno("calloc");
736 
737 	pack->privsep_child = calloc(1, sizeof(*pack->privsep_child));
738 	if (pack->privsep_child == NULL) {
739 		err = got_error_from_errno("calloc");
740 		free(ibuf);
741 		return err;
742 	}
743 	pack->child_has_tempfiles = 0;
744 	pack->child_has_delta_outfd = 0;
745 
746 	if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, imsg_fds) == -1) {
747 		err = got_error_from_errno("socketpair");
748 		goto done;
749 	}
750 
751 	pid = fork();
752 	if (pid == -1) {
753 		err = got_error_from_errno("fork");
754 		goto done;
755 	} else if (pid == 0) {
756 		set_max_datasize();
757 		got_privsep_exec_child(imsg_fds, GOT_PATH_PROG_READ_PACK,
758 		    pack->path_packfile);
759 		/* not reached */
760 	}
761 
762 	if (close(imsg_fds[1]) == -1)
763 		return got_error_from_errno("close");
764 	pack->privsep_child->imsg_fd = imsg_fds[0];
765 	pack->privsep_child->pid = pid;
766 	imsg_init(ibuf, imsg_fds[0]);
767 	pack->privsep_child->ibuf = ibuf;
768 
769 	err = got_privsep_init_pack_child(ibuf, pack, packidx);
770 	if (err) {
771 		const struct got_error *child_err;
772 		err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
773 		child_err = got_privsep_wait_for_child(
774 		    pack->privsep_child->pid);
775 		if (child_err && err == NULL)
776 			err = child_err;
777 	}
778 done:
779 	if (err) {
780 		free(ibuf);
781 		free(pack->privsep_child);
782 		pack->privsep_child = NULL;
783 	}
784 	return err;
785 }
786 
787 static const struct got_error *
788 pack_stop_privsep_child(struct got_pack *pack)
789 {
790 	const struct got_error *err = NULL;
791 
792 	if (pack->privsep_child == NULL)
793 		return NULL;
794 
795 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
796 	if (err)
797 		return err;
798 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
799 	if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
800 		err = got_error_from_errno("close");
801 	free(pack->privsep_child->ibuf);
802 	free(pack->privsep_child);
803 	pack->privsep_child = NULL;
804 	return err;
805 }
806 
807 const struct got_error *
808 got_pack_close(struct got_pack *pack)
809 {
810 	const struct got_error *err = NULL;
811 
812 	err = pack_stop_privsep_child(pack);
813 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
814 		err = got_error_from_errno("munmap");
815 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
816 		err = got_error_from_errno("close");
817 	pack->fd = -1;
818 	free(pack->path_packfile);
819 	pack->path_packfile = NULL;
820 	pack->filesize = 0;
821 	if (pack->delta_cache) {
822 		got_delta_cache_free(pack->delta_cache);
823 		pack->delta_cache = NULL;
824 	}
825 
826 	/*
827 	 * Leave accumfd and basefd alone. They are managed by the
828 	 * repository layer and can be reused.
829 	 */
830 
831 	return err;
832 }
833 
834 const struct got_error *
835 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
836     struct got_pack *pack, off_t offset)
837 {
838 	uint8_t t = 0;
839 	uint64_t s = 0;
840 	uint8_t sizeN;
841 	size_t mapoff = 0;
842 	int i = 0;
843 
844 	*len = 0;
845 
846 	if (offset >= pack->filesize)
847 		return got_error(GOT_ERR_PACK_OFFSET);
848 
849 	if (pack->map) {
850 		mapoff = (size_t)offset;
851 	} else {
852 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
853 			return got_error_from_errno("lseek");
854 	}
855 
856 	do {
857 		/* We do not support size values which don't fit in 64 bit. */
858 		if (i > 9)
859 			return got_error(GOT_ERR_NO_SPACE);
860 
861 		if (pack->map) {
862 			if (mapoff + sizeof(sizeN) >= pack->filesize)
863 				return got_error(GOT_ERR_BAD_PACKFILE);
864 			sizeN = *(pack->map + mapoff);
865 			mapoff += sizeof(sizeN);
866 		} else {
867 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
868 			if (n < 0)
869 				return got_error_from_errno("read");
870 			if (n != sizeof(sizeN))
871 				return got_error(GOT_ERR_BAD_PACKFILE);
872 		}
873 		*len += sizeof(sizeN);
874 
875 		if (i == 0) {
876 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
877 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
878 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
879 		} else {
880 			size_t shift = 4 + 7 * (i - 1);
881 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
882 		}
883 		i++;
884 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
885 
886 	*type = t;
887 	*size = s;
888 	return NULL;
889 }
890 
891 static const struct got_error *
892 open_plain_object(struct got_object **obj, struct got_object_id *id,
893     uint8_t type, off_t offset, size_t size, int idx)
894 {
895 	*obj = calloc(1, sizeof(**obj));
896 	if (*obj == NULL)
897 		return got_error_from_errno("calloc");
898 
899 	(*obj)->type = type;
900 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
901 	(*obj)->pack_idx = idx;
902 	(*obj)->hdrlen = 0;
903 	(*obj)->size = size;
904 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
905 	(*obj)->pack_offset = offset;
906 
907 	return NULL;
908 }
909 
910 static const struct got_error *
911 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
912     off_t delta_offset)
913 {
914 	int64_t o = 0;
915 	uint8_t offN;
916 	int i = 0;
917 
918 	*offset = 0;
919 	*len = 0;
920 
921 	do {
922 		/* We do not support offset values which don't fit in 64 bit. */
923 		if (i > 8)
924 			return got_error(GOT_ERR_NO_SPACE);
925 
926 		if (pack->map) {
927 			size_t mapoff;
928 			mapoff = (size_t)delta_offset + *len;
929 			if (mapoff + sizeof(offN) >= pack->filesize)
930 				return got_error(GOT_ERR_PACK_OFFSET);
931 			offN = *(pack->map + mapoff);
932 		} else {
933 			ssize_t n;
934 			n = read(pack->fd, &offN, sizeof(offN));
935 			if (n < 0)
936 				return got_error_from_errno("read");
937 			if (n != sizeof(offN))
938 				return got_error(GOT_ERR_BAD_PACKFILE);
939 		}
940 		*len += sizeof(offN);
941 
942 		if (i == 0)
943 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
944 		else {
945 			o++;
946 			o <<= 7;
947 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
948 		}
949 		i++;
950 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
951 
952 	*offset = o;
953 	return NULL;
954 }
955 
956 const struct got_error *
957 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
958     struct got_pack *pack, off_t offset, int tslen)
959 {
960 	const struct got_error *err;
961 	int64_t negoffset;
962 	size_t negofflen;
963 
964 	*len = 0;
965 
966 	err = parse_negative_offset(&negoffset, &negofflen, pack,
967 	    offset + tslen);
968 	if (err)
969 		return err;
970 
971 	/* Compute the base object's offset (must be in the same pack file). */
972 	*base_offset = (offset - negoffset);
973 	if (*base_offset <= 0)
974 		return got_error(GOT_ERR_BAD_PACKFILE);
975 
976 	*len = negofflen;
977 	return NULL;
978 }
979 
980 static const struct got_error *
981 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
982     size_t *delta_compressed_len, size_t delta_data_offset,
983     struct got_pack *pack)
984 {
985 	const struct got_error *err = NULL;
986 	size_t consumed = 0;
987 
988 	if (pack->map) {
989 		if (delta_data_offset >= pack->filesize)
990 			return got_error(GOT_ERR_PACK_OFFSET);
991 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
992 		    &consumed, NULL, pack->map, delta_data_offset,
993 		    pack->filesize - delta_data_offset);
994 		if (err)
995 			return err;
996 	} else {
997 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
998 			return got_error_from_errno("lseek");
999 		err = got_inflate_to_mem_fd(delta_buf, delta_len,
1000 		    &consumed, NULL, 0, pack->fd);
1001 		if (err)
1002 			return err;
1003 	}
1004 
1005 	if (delta_compressed_len)
1006 		*delta_compressed_len = consumed;
1007 
1008 	return NULL;
1009 }
1010 
1011 static const struct got_error *
1012 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
1013     int delta_type, size_t delta_size, size_t delta_data_offset)
1014 {
1015 	struct got_delta *delta;
1016 
1017 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
1018 	    delta_data_offset);
1019 	if (delta == NULL)
1020 		return got_error_from_errno("got_delta_open");
1021 	/* delta is freed in got_object_close() */
1022 	deltas->nentries++;
1023 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
1024 	return NULL;
1025 }
1026 
1027 static const struct got_error *
1028 resolve_offset_delta(struct got_delta_chain *deltas,
1029     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1030     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1031 
1032 {
1033 	const struct got_error *err;
1034 	off_t base_offset;
1035 	uint8_t base_type;
1036 	uint64_t base_size;
1037 	size_t base_tslen;
1038 	off_t delta_data_offset;
1039 	size_t consumed;
1040 
1041 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
1042 	    delta_offset, tslen);
1043 	if (err)
1044 		return err;
1045 
1046 	delta_data_offset = delta_offset + tslen + consumed;
1047 	if (delta_data_offset >= pack->filesize)
1048 		return got_error(GOT_ERR_PACK_OFFSET);
1049 
1050 	if (pack->map == NULL) {
1051 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1052 		if (delta_data_offset == -1)
1053 			return got_error_from_errno("lseek");
1054 	}
1055 
1056 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1057 	    delta_data_offset);
1058 	if (err)
1059 		return err;
1060 
1061 	/* An offset delta must be in the same packfile. */
1062 	if (base_offset >= pack->filesize)
1063 		return got_error(GOT_ERR_PACK_OFFSET);
1064 
1065 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1066 	    &base_tslen, pack, base_offset);
1067 	if (err)
1068 		return err;
1069 
1070 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1071 	    base_tslen, base_type, base_size, recursion - 1);
1072 }
1073 
1074 const struct got_error *
1075 got_pack_parse_ref_delta(struct got_object_id *id,
1076     struct got_pack *pack, off_t delta_offset, int tslen)
1077 {
1078 	if (pack->map) {
1079 		size_t mapoff = delta_offset + tslen;
1080 		if (mapoff + sizeof(*id) >= pack->filesize)
1081 			return got_error(GOT_ERR_PACK_OFFSET);
1082 		memcpy(id, pack->map + mapoff, sizeof(*id));
1083 	} else {
1084 		ssize_t n;
1085 		n = read(pack->fd, id, sizeof(*id));
1086 		if (n < 0)
1087 			return got_error_from_errno("read");
1088 		if (n != sizeof(*id))
1089 			return got_error(GOT_ERR_BAD_PACKFILE);
1090 	}
1091 
1092 	return NULL;
1093 }
1094 
1095 static const struct got_error *
1096 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1097     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1098     size_t delta_size, unsigned int recursion)
1099 {
1100 	const struct got_error *err;
1101 	struct got_object_id id;
1102 	int idx;
1103 	off_t base_offset;
1104 	uint8_t base_type;
1105 	uint64_t base_size;
1106 	size_t base_tslen;
1107 	off_t delta_data_offset;
1108 
1109 	if (delta_offset + tslen >= pack->filesize)
1110 		return got_error(GOT_ERR_PACK_OFFSET);
1111 
1112 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1113 	if (err)
1114 		return err;
1115 	if (pack->map) {
1116 		delta_data_offset = delta_offset + tslen + sizeof(id);
1117 	} else {
1118 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1119 		if (delta_data_offset == -1)
1120 			return got_error_from_errno("lseek");
1121 	}
1122 
1123 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1124 	    delta_data_offset);
1125 	if (err)
1126 		return err;
1127 
1128 	/* Delta base must be in the same pack file. */
1129 	idx = got_packidx_get_object_idx(packidx, &id);
1130 	if (idx == -1)
1131 		return got_error(GOT_ERR_NO_OBJ);
1132 
1133 	base_offset = got_packidx_get_object_offset(packidx, idx);
1134 	if (base_offset == (uint64_t)-1)
1135 		return got_error(GOT_ERR_BAD_PACKIDX);
1136 
1137 	if (base_offset >= pack->filesize)
1138 		return got_error(GOT_ERR_PACK_OFFSET);
1139 
1140 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1141 	    &base_tslen, pack, base_offset);
1142 	if (err)
1143 		return err;
1144 
1145 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1146 	    base_tslen, base_type, base_size, recursion - 1);
1147 }
1148 
1149 const struct got_error *
1150 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1151     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1152     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1153 {
1154 	const struct got_error *err = NULL;
1155 
1156 	if (--recursion == 0)
1157 		return got_error(GOT_ERR_RECURSION);
1158 
1159 	switch (delta_type) {
1160 	case GOT_OBJ_TYPE_COMMIT:
1161 	case GOT_OBJ_TYPE_TREE:
1162 	case GOT_OBJ_TYPE_BLOB:
1163 	case GOT_OBJ_TYPE_TAG:
1164 		/* Plain types are the final delta base. Recursion ends. */
1165 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1166 		    delta_size, 0);
1167 		break;
1168 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1169 		err = resolve_offset_delta(deltas, packidx, pack,
1170 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1171 		break;
1172 	case GOT_OBJ_TYPE_REF_DELTA:
1173 		err = resolve_ref_delta(deltas, packidx, pack,
1174 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1175 		break;
1176 	default:
1177 		return got_error(GOT_ERR_OBJ_TYPE);
1178 	}
1179 
1180 	return err;
1181 }
1182 
1183 static const struct got_error *
1184 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1185     struct got_pack *pack, struct got_object_id *id, off_t offset,
1186     size_t tslen, int delta_type, size_t delta_size, int idx)
1187 {
1188 	const struct got_error *err = NULL;
1189 	int resolved_type;
1190 
1191 	*obj = calloc(1, sizeof(**obj));
1192 	if (*obj == NULL)
1193 		return got_error_from_errno("calloc");
1194 
1195 	(*obj)->flags = 0;
1196 	(*obj)->hdrlen = 0;
1197 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1198 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1199 	(*obj)->pack_offset = offset + tslen;
1200 
1201 	STAILQ_INIT(&(*obj)->deltas.entries);
1202 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1203 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1204 	(*obj)->pack_idx = idx;
1205 
1206 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1207 	    offset, tslen, delta_type, delta_size,
1208 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1209 	if (err)
1210 		goto done;
1211 
1212 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1213 	if (err)
1214 		goto done;
1215 	(*obj)->type = resolved_type;
1216 done:
1217 	if (err) {
1218 		got_object_close(*obj);
1219 		*obj = NULL;
1220 	}
1221 	return err;
1222 }
1223 
1224 const struct got_error *
1225 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1226     struct got_packidx *packidx, int idx, struct got_object_id *id)
1227 {
1228 	const struct got_error *err = NULL;
1229 	off_t offset;
1230 	uint8_t type;
1231 	uint64_t size;
1232 	size_t tslen;
1233 
1234 	*obj = NULL;
1235 
1236 	offset = got_packidx_get_object_offset(packidx, idx);
1237 	if (offset == (uint64_t)-1)
1238 		return got_error(GOT_ERR_BAD_PACKIDX);
1239 
1240 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1241 	    pack, offset);
1242 	if (err)
1243 		return err;
1244 
1245 	switch (type) {
1246 	case GOT_OBJ_TYPE_COMMIT:
1247 	case GOT_OBJ_TYPE_TREE:
1248 	case GOT_OBJ_TYPE_BLOB:
1249 	case GOT_OBJ_TYPE_TAG:
1250 		err = open_plain_object(obj, id, type, offset + tslen,
1251 		    size, idx);
1252 		break;
1253 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1254 	case GOT_OBJ_TYPE_REF_DELTA:
1255 		err = open_delta_object(obj, packidx, pack, id, offset,
1256 		    tslen, type, size, idx);
1257 		break;
1258 	default:
1259 		err = got_error(GOT_ERR_OBJ_TYPE);
1260 		break;
1261 	}
1262 
1263 	return err;
1264 }
1265 
1266 const struct got_error *
1267 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1268     struct got_delta_chain *deltas, struct got_pack *pack)
1269 {
1270 	struct got_delta *delta;
1271 	uint64_t base_size = 0, result_size = 0;
1272 
1273 	*max_size = 0;
1274 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1275 		/* Plain object types are the delta base. */
1276 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1277 		    delta->type != GOT_OBJ_TYPE_TREE &&
1278 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1279 		    delta->type != GOT_OBJ_TYPE_TAG) {
1280 			const struct got_error *err;
1281 			uint8_t *delta_buf;
1282 			size_t delta_len;
1283 			int cached = 1;
1284 
1285 			got_delta_cache_get(&delta_buf, &delta_len,
1286 			    pack->delta_cache, delta->data_offset);
1287 			if (delta_buf == NULL) {
1288 				cached = 0;
1289 				err = read_delta_data(&delta_buf, &delta_len,
1290 				    NULL, delta->data_offset, pack);
1291 				if (err)
1292 					return err;
1293 				err = got_delta_cache_add(pack->delta_cache,
1294 				    delta->data_offset, delta_buf, delta_len);
1295 				if (err == NULL)
1296 					cached = 1;
1297 				else if (err->code != GOT_ERR_NO_SPACE) {
1298 					free(delta_buf);
1299 					return err;
1300 				}
1301 			}
1302 			err = got_delta_get_sizes(&base_size, &result_size,
1303 			    delta_buf, delta_len);
1304 			if (!cached)
1305 				free(delta_buf);
1306 			if (err)
1307 				return err;
1308 		} else
1309 			base_size = delta->size;
1310 		if (base_size > *max_size)
1311 			*max_size = base_size;
1312 		if (result_size > *max_size)
1313 			*max_size = result_size;
1314 	}
1315 
1316 	return NULL;
1317 }
1318 
1319 const struct got_error *
1320 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1321     struct got_pack *pack)
1322 {
1323 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1324 		return got_error(GOT_ERR_OBJ_TYPE);
1325 
1326 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1327 }
1328 
1329 const struct got_error *
1330 got_pack_dump_delta_chain_to_file(size_t *result_size,
1331     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1332     FILE *base_file, FILE *accum_file)
1333 {
1334 	const struct got_error *err = NULL;
1335 	struct got_delta *delta;
1336 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1337 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1338 	/* We process small enough files entirely in memory for speed. */
1339 	const size_t max_bufsize = GOT_DELTA_RESULT_SIZE_CACHED_MAX;
1340 	uint64_t max_size = 0;
1341 	int n = 0;
1342 
1343 	*result_size = 0;
1344 
1345 	if (STAILQ_EMPTY(&deltas->entries))
1346 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1347 
1348 	if (fseeko(base_file, 0L, SEEK_SET) == -1)
1349 		return got_error_from_errno("fseeko");
1350 	if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1351 		return got_error_from_errno("fseeko");
1352 
1353 	/* Deltas are ordered in ascending order. */
1354 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1355 		uint64_t base_size, result_size = 0;
1356 		int cached = 1;
1357 		if (n == 0) {
1358 			size_t mapoff;
1359 			off_t delta_data_offset;
1360 
1361 			/* Plain object types are the delta base. */
1362 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1363 			    delta->type != GOT_OBJ_TYPE_TREE &&
1364 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1365 			    delta->type != GOT_OBJ_TYPE_TAG) {
1366 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1367 				goto done;
1368 			}
1369 
1370 			delta_data_offset = delta->offset + delta->tslen;
1371 			if (delta_data_offset >= pack->filesize) {
1372 				err = got_error(GOT_ERR_PACK_OFFSET);
1373 				goto done;
1374 			}
1375 			if (pack->map == NULL) {
1376 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1377 				    == -1) {
1378 					err = got_error_from_errno("lseek");
1379 					goto done;
1380 				}
1381 			}
1382 			if (delta->size > max_size)
1383 				max_size = delta->size;
1384 			if (max_size > max_bufsize) {
1385 				if (pack->map) {
1386 					mapoff = (size_t)delta_data_offset;
1387 					err = got_inflate_to_file_mmap(
1388 					    &base_bufsz, NULL, NULL, pack->map,
1389 					    mapoff, pack->filesize - mapoff,
1390 					    base_file);
1391 				} else
1392 					err = got_inflate_to_file_fd(
1393 					    &base_bufsz, NULL, NULL, pack->fd,
1394 					    base_file);
1395 			} else {
1396 				accum_buf = malloc(max_size);
1397 				if (accum_buf == NULL) {
1398 					err = got_error_from_errno("malloc");
1399 					goto done;
1400 				}
1401 				accum_bufsz = max_size;
1402 				if (pack->map) {
1403 					mapoff = (size_t)delta_data_offset;
1404 					err = got_inflate_to_mem_mmap(&base_buf,
1405 					    &base_bufsz, NULL, NULL,
1406 					    pack->map, mapoff,
1407 					    pack->filesize - mapoff);
1408 				} else
1409 					err = got_inflate_to_mem_fd(&base_buf,
1410 					    &base_bufsz, NULL, NULL, max_size,
1411 					    pack->fd);
1412 			}
1413 			if (err)
1414 				goto done;
1415 			n++;
1416 			if (base_buf == NULL)
1417 				rewind(base_file);
1418 			continue;
1419 		}
1420 
1421 		got_delta_cache_get(&delta_buf, &delta_len,
1422 		    pack->delta_cache, delta->data_offset);
1423 		if (delta_buf == NULL) {
1424 			cached = 0;
1425 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1426 			    delta->data_offset, pack);
1427 			if (err)
1428 				goto done;
1429 			err = got_delta_cache_add(pack->delta_cache,
1430 			    delta->data_offset, delta_buf, delta_len);
1431 			if (err == NULL)
1432 				cached = 1;
1433 			else if (err->code != GOT_ERR_NO_SPACE) {
1434 				free(delta_buf);
1435 				goto done;
1436 			}
1437 		}
1438 
1439 		err = got_delta_get_sizes(&base_size, &result_size,
1440 		    delta_buf, delta_len);
1441 		if (err)
1442 			goto done;
1443 		if (base_size > max_size)
1444 			max_size = base_size;
1445 		if (result_size > max_size)
1446 			max_size = result_size;
1447 
1448 		if (base_buf && max_size > max_bufsize) {
1449 			/* Switch from buffers to temporary files. */
1450 			size_t w = fwrite(base_buf, 1, base_bufsz,
1451 			    base_file);
1452 			if (w != base_bufsz) {
1453 				err = got_ferror(outfile, GOT_ERR_IO);
1454 				goto done;
1455 			}
1456 			free(base_buf);
1457 			base_buf = NULL;
1458 			free(accum_buf);
1459 			accum_buf = NULL;
1460 		}
1461 
1462 		if (base_buf && max_size > base_bufsz) {
1463 			uint8_t *p = realloc(base_buf, max_size);
1464 			if (p == NULL) {
1465 				err = got_error_from_errno("realloc");
1466 				goto done;
1467 			}
1468 			base_buf = p;
1469 			base_bufsz = max_size;
1470 		}
1471 
1472 		if (accum_buf && max_size > accum_bufsz) {
1473 			uint8_t *p = realloc(accum_buf, max_size);
1474 			if (p == NULL) {
1475 				err = got_error_from_errno("realloc");
1476 				goto done;
1477 			}
1478 			accum_buf = p;
1479 			accum_bufsz = max_size;
1480 		}
1481 
1482 		if (base_buf) {
1483 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1484 			    delta_buf, delta_len, accum_buf,
1485 			    &accum_size, max_size);
1486 			n++;
1487 		} else {
1488 			err = got_delta_apply(base_file, delta_buf,
1489 			    delta_len,
1490 			    /* Final delta application writes to output file. */
1491 			    ++n < deltas->nentries ? accum_file : outfile,
1492 			    &accum_size);
1493 		}
1494 		if (!cached)
1495 			free(delta_buf);
1496 		if (err)
1497 			goto done;
1498 
1499 		if (n < deltas->nentries) {
1500 			/* Accumulated delta becomes the new base. */
1501 			if (base_buf) {
1502 				uint8_t *tmp = accum_buf;
1503 				size_t tmp_size = accum_bufsz;
1504 				accum_buf = base_buf;
1505 				accum_bufsz = base_bufsz;
1506 				base_buf = tmp;
1507 				base_bufsz = tmp_size;
1508 			} else {
1509 				FILE *tmp = accum_file;
1510 				accum_file = base_file;
1511 				base_file = tmp;
1512 				rewind(base_file);
1513 				rewind(accum_file);
1514 			}
1515 		}
1516 	}
1517 
1518 done:
1519 	free(base_buf);
1520 	if (accum_buf) {
1521 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1522 		free(accum_buf);
1523 		if (len != accum_size)
1524 			err = got_ferror(outfile, GOT_ERR_IO);
1525 	}
1526 	rewind(outfile);
1527 	if (err == NULL)
1528 		*result_size = accum_size;
1529 	return err;
1530 }
1531 
1532 const struct got_error *
1533 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1534     struct got_delta_chain *deltas, struct got_pack *pack)
1535 {
1536 	const struct got_error *err = NULL;
1537 	struct got_delta *delta;
1538 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1539 	size_t base_bufsz = 0, accum_bufsz = 0, accum_size = 0, delta_len;
1540 	uint64_t max_size = 0;
1541 	int n = 0;
1542 
1543 	*outbuf = NULL;
1544 	*outlen = 0;
1545 
1546 	if (STAILQ_EMPTY(&deltas->entries))
1547 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1548 
1549 	/* Deltas are ordered in ascending order. */
1550 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1551 		uint64_t base_size, result_size = 0;
1552 		int cached = 1;
1553 		if (n == 0) {
1554 			size_t delta_data_offset;
1555 
1556 			/* Plain object types are the delta base. */
1557 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1558 			    delta->type != GOT_OBJ_TYPE_TREE &&
1559 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1560 			    delta->type != GOT_OBJ_TYPE_TAG) {
1561 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1562 				goto done;
1563 			}
1564 
1565 			delta_data_offset = delta->offset + delta->tslen;
1566 			if (delta_data_offset >= pack->filesize) {
1567 				err = got_error(GOT_ERR_PACK_OFFSET);
1568 				goto done;
1569 			}
1570 
1571 			if (delta->size > max_size)
1572 				max_size = delta->size;
1573 
1574 			if (pack->map) {
1575 				size_t mapoff = (size_t)delta_data_offset;
1576 				err = got_inflate_to_mem_mmap(&base_buf,
1577 				    &base_bufsz, NULL, NULL, pack->map,
1578 				    mapoff, pack->filesize - mapoff);
1579 			} else {
1580 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1581 				    == -1) {
1582 					err = got_error_from_errno("lseek");
1583 					goto done;
1584 				}
1585 				err = got_inflate_to_mem_fd(&base_buf,
1586 				    &base_bufsz, NULL, NULL, max_size,
1587 				    pack->fd);
1588 			}
1589 			if (err)
1590 				goto done;
1591 			n++;
1592 			continue;
1593 		}
1594 
1595 		got_delta_cache_get(&delta_buf, &delta_len,
1596 		    pack->delta_cache, delta->data_offset);
1597 		if (delta_buf == NULL) {
1598 			cached = 0;
1599 			err = read_delta_data(&delta_buf, &delta_len, NULL,
1600 			    delta->data_offset, pack);
1601 			if (err)
1602 				goto done;
1603 			err = got_delta_cache_add(pack->delta_cache,
1604 			    delta->data_offset, delta_buf, delta_len);
1605 			if (err == NULL)
1606 				cached = 1;
1607 			else if (err->code != GOT_ERR_NO_SPACE) {
1608 				free(delta_buf);
1609 				goto done;
1610 			}
1611 		}
1612 
1613 		err = got_delta_get_sizes(&base_size, &result_size,
1614 		    delta_buf, delta_len);
1615 		if (err)
1616 			goto done;
1617 		if (base_size > max_size)
1618 			max_size = base_size;
1619 		if (result_size > max_size)
1620 			max_size = result_size;
1621 
1622 		if (max_size > base_bufsz) {
1623 			uint8_t *p = realloc(base_buf, max_size);
1624 			if (p == NULL) {
1625 				err = got_error_from_errno("realloc");
1626 				goto done;
1627 			}
1628 			base_buf = p;
1629 			base_bufsz = max_size;
1630 		}
1631 
1632 		if (max_size > accum_bufsz) {
1633 			uint8_t *p = realloc(accum_buf, max_size);
1634 			if (p == NULL) {
1635 				err = got_error_from_errno("realloc");
1636 				goto done;
1637 			}
1638 			accum_buf = p;
1639 			accum_bufsz = max_size;
1640 		}
1641 
1642 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1643 		    delta_buf, delta_len, accum_buf,
1644 		    &accum_size, max_size);
1645 		if (!cached)
1646 			free(delta_buf);
1647 		n++;
1648 		if (err)
1649 			goto done;
1650 
1651 		if (n < deltas->nentries) {
1652 			/* Accumulated delta becomes the new base. */
1653 			uint8_t *tmp = accum_buf;
1654 			size_t tmp_size = accum_bufsz;
1655 			accum_buf = base_buf;
1656 			accum_bufsz = base_bufsz;
1657 			base_buf = tmp;
1658 			base_bufsz = tmp_size;
1659 		}
1660 	}
1661 
1662 done:
1663 	free(base_buf);
1664 	if (err) {
1665 		free(accum_buf);
1666 		*outbuf = NULL;
1667 		*outlen = 0;
1668 	} else {
1669 		*outbuf = accum_buf;
1670 		*outlen = accum_size;
1671 	}
1672 	return err;
1673 }
1674 
1675 const struct got_error *
1676 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1677     FILE *outfile, FILE *base_file, FILE *accum_file)
1678 {
1679 	const struct got_error *err = NULL;
1680 
1681 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1682 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1683 
1684 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1685 		if (obj->pack_offset >= pack->filesize)
1686 			return got_error(GOT_ERR_PACK_OFFSET);
1687 
1688 		if (pack->map) {
1689 			size_t mapoff = (size_t)obj->pack_offset;
1690 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1691 			    pack->map, mapoff, pack->filesize - mapoff,
1692 			    outfile);
1693 		} else {
1694 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1695 				return got_error_from_errno("lseek");
1696 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1697 			    pack->fd, outfile);
1698 		}
1699 	} else
1700 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1701 		    &obj->deltas, pack, outfile, base_file, accum_file);
1702 
1703 	return err;
1704 }
1705 
1706 const struct got_error *
1707 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1708     struct got_object *obj, struct got_pack *pack)
1709 {
1710 	const struct got_error *err = NULL;
1711 
1712 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1713 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1714 
1715 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1716 		if (obj->pack_offset >= pack->filesize)
1717 			return got_error(GOT_ERR_PACK_OFFSET);
1718 		if (pack->map) {
1719 			size_t mapoff = (size_t)obj->pack_offset;
1720 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1721 			    pack->map, mapoff, pack->filesize - mapoff);
1722 		} else {
1723 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1724 				return got_error_from_errno("lseek");
1725 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1726 			    obj->size, pack->fd);
1727 		}
1728 	} else
1729 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1730 		    pack);
1731 
1732 	return err;
1733 }
1734 
1735 static const struct got_error *
1736 read_raw_delta_data(uint8_t **delta_buf, size_t *delta_len,
1737     size_t *delta_len_compressed, uint64_t *base_size, uint64_t *result_size,
1738     off_t delta_data_offset, struct got_pack *pack, struct got_packidx *packidx)
1739 {
1740 	const struct got_error *err = NULL;
1741 
1742 	/* Validate decompression and obtain the decompressed size. */
1743 	err = read_delta_data(delta_buf, delta_len, delta_len_compressed,
1744 	    delta_data_offset, pack);
1745 	if (err)
1746 		return err;
1747 
1748 	/* Read delta base/result sizes from head of delta stream. */
1749 	err = got_delta_get_sizes(base_size, result_size,
1750 	    *delta_buf, *delta_len);
1751 	if (err)
1752 		goto done;
1753 
1754 	/* Discard decompressed delta and read it again in compressed form. */
1755 	free(*delta_buf);
1756 	*delta_buf = malloc(*delta_len_compressed);
1757 	if (*delta_buf == NULL) {
1758 		err = got_error_from_errno("malloc");
1759 		goto done;
1760 	}
1761 	if (pack->map) {
1762 		if (delta_data_offset >= pack->filesize)
1763 			err = got_error(GOT_ERR_PACK_OFFSET);
1764 		memcpy(*delta_buf, pack->map + delta_data_offset,
1765 		    *delta_len_compressed);
1766 	} else {
1767 		ssize_t n;
1768 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1) {
1769 			err = got_error_from_errno("lseek");
1770 			goto done;
1771 		}
1772 		n = read(pack->fd, *delta_buf, *delta_len_compressed);
1773 		if (n < 0) {
1774 			err = got_error_from_errno("read");
1775 			goto done;
1776 		} else if (n != *delta_len_compressed) {
1777 			err = got_error(GOT_ERR_IO);
1778 			goto done;
1779 		}
1780 	}
1781 done:
1782 	if (err) {
1783 		free(*delta_buf);
1784 		*delta_buf = NULL;
1785 		*delta_len = 0;
1786 		*delta_len_compressed = 0;
1787 		*base_size = 0;
1788 		*result_size = 0;
1789 	}
1790 	return err;
1791 }
1792 
1793 const struct got_error *
1794 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1795     size_t *delta_compressed_size, off_t *delta_offset, off_t *base_offset,
1796     struct got_object_id *base_id, uint64_t *base_size, uint64_t *result_size,
1797     struct got_pack *pack, struct got_packidx *packidx, int idx)
1798 {
1799 	const struct got_error *err = NULL;
1800 	off_t offset;
1801 	uint8_t type;
1802 	uint64_t size;
1803 	size_t tslen, delta_hdrlen;
1804 	off_t delta_data_offset;
1805 
1806 	*delta_buf = NULL;
1807 	*delta_size = 0;
1808 	*delta_compressed_size = 0;
1809 	*delta_offset = 0;
1810 	*base_offset = 0;
1811 	*base_size = 0;
1812 	*result_size = 0;
1813 
1814 	offset = got_packidx_get_object_offset(packidx, idx);
1815 	if (offset == (uint64_t)-1)
1816 		return got_error(GOT_ERR_BAD_PACKIDX);
1817 
1818 	if (offset >= pack->filesize)
1819 		return got_error(GOT_ERR_PACK_OFFSET);
1820 
1821 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1822 	    pack, offset);
1823 	if (err)
1824 		return err;
1825 
1826 	if (tslen + size < tslen || offset + size < size ||
1827 	    tslen + offset < tslen)
1828 		return got_error(GOT_ERR_PACK_OFFSET);
1829 
1830 	switch (type) {
1831 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1832 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1833 		    pack, offset, tslen);
1834 		if (err)
1835 			return err;
1836 		break;
1837 	case GOT_OBJ_TYPE_REF_DELTA:
1838 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1839 		if (err)
1840 			return err;
1841 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1842 		break;
1843 	default:
1844 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1845 		    "non-delta object type %d found at offset %llu",
1846 		    type, offset);
1847 	}
1848 
1849 	if (tslen + delta_hdrlen < delta_hdrlen ||
1850 	    offset + delta_hdrlen < delta_hdrlen)
1851 		return got_error(GOT_ERR_BAD_DELTA);
1852 
1853 	delta_data_offset = offset + tslen + delta_hdrlen;
1854 	err = read_raw_delta_data(delta_buf, delta_size, delta_compressed_size,
1855 	    base_size, result_size, delta_data_offset, pack, packidx);
1856 	if (err)
1857 		return err;
1858 
1859 	if (*delta_size != size) {
1860 		err = got_error(GOT_ERR_BAD_DELTA);
1861 		goto done;
1862 	}
1863 
1864 	*delta_offset = offset;
1865 done:
1866 	if (err) {
1867 		free(*delta_buf);
1868 		*delta_buf = NULL;
1869 		*delta_size = 0;
1870 		*delta_compressed_size = 0;
1871 		*delta_offset = 0;
1872 		*base_offset = 0;
1873 		*base_size = 0;
1874 		*result_size = 0;
1875 	}
1876 	return err;
1877 }