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Date:: Mon Feb 14 13:14:36 2022 UTC
Message:: factorize imsg_clear calls after imsg_flush failures imsg_clear frees and closes resources allocated as part of enqueueing imsgs so it's a no-op after reads. discussed with and ok stsp@
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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/queue.h>
20 #include <sys/uio.h>
21 #include <sys/mman.h>
22 
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <unistd.h>
33 #include <zlib.h>
34 #include <imsg.h>
35 
36 #include "got_error.h"
37 #include "got_object.h"
38 #include "got_opentemp.h"
39 #include "got_path.h"
40 
41 #include "got_lib_sha1.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_delta_cache.h"
44 #include "got_lib_inflate.h"
45 #include "got_lib_object.h"
46 #include "got_lib_object_parse.h"
47 #include "got_lib_privsep.h"
48 #include "got_lib_pack.h"
49 
50 #ifndef nitems
51 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
52 #endif
53 
54 #ifndef MIN
55 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
56 #endif
57 
58 static const struct got_error *
59 verify_fanout_table(uint32_t *fanout_table)
60 {
61 	int i;
62 
63 	for (i = 0; i < 0xff - 1; i++) {
64 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
65 			return got_error(GOT_ERR_BAD_PACKIDX);
66 	}
67 
68 	return NULL;
69 }
70 
71 const struct got_error *
72 got_packidx_init_hdr(struct got_packidx *p, int verify, off_t packfile_size)
73 {
74 	const struct got_error *err = NULL;
75 	struct got_packidx_v2_hdr *h;
76 	SHA1_CTX ctx;
77 	uint8_t sha1[SHA1_DIGEST_LENGTH];
78 	size_t nobj, len_fanout, len_ids, offset, remain;
79 	ssize_t n;
80 	int i;
81 
82 	SHA1Init(&ctx);
83 
84 	h = &p->hdr;
85 	offset = 0;
86 	remain = p->len;
87 
88 	if (remain < sizeof(*h->magic)) {
89 		err = got_error(GOT_ERR_BAD_PACKIDX);
90 		goto done;
91 	}
92 	if (p->map)
93 		h->magic = (uint32_t *)(p->map + offset);
94 	else {
95 		h->magic = malloc(sizeof(*h->magic));
96 		if (h->magic == NULL) {
97 			err = got_error_from_errno("malloc");
98 			goto done;
99 		}
100 		n = read(p->fd, h->magic, sizeof(*h->magic));
101 		if (n < 0) {
102 			err = got_error_from_errno("read");
103 			goto done;
104 		} else if (n != sizeof(*h->magic)) {
105 			err = got_error(GOT_ERR_BAD_PACKIDX);
106 			goto done;
107 		}
108 	}
109 	if (*h->magic != htobe32(GOT_PACKIDX_V2_MAGIC)) {
110 		err = got_error(GOT_ERR_BAD_PACKIDX);
111 		goto done;
112 	}
113 	offset += sizeof(*h->magic);
114 	remain -= sizeof(*h->magic);
115 
116 	if (verify)
117 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
118 
119 	if (remain < sizeof(*h->version)) {
120 		err = got_error(GOT_ERR_BAD_PACKIDX);
121 		goto done;
122 	}
123 	if (p->map)
124 		h->version = (uint32_t *)(p->map + offset);
125 	else {
126 		h->version = malloc(sizeof(*h->version));
127 		if (h->version == NULL) {
128 			err = got_error_from_errno("malloc");
129 			goto done;
130 		}
131 		n = read(p->fd, h->version, sizeof(*h->version));
132 		if (n < 0) {
133 			err = got_error_from_errno("read");
134 			goto done;
135 		} else if (n != sizeof(*h->version)) {
136 			err = got_error(GOT_ERR_BAD_PACKIDX);
137 			goto done;
138 		}
139 	}
140 	if (*h->version != htobe32(GOT_PACKIDX_VERSION)) {
141 		err = got_error(GOT_ERR_BAD_PACKIDX);
142 		goto done;
143 	}
144 	offset += sizeof(*h->version);
145 	remain -= sizeof(*h->version);
146 
147 	if (verify)
148 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
149 
150 	len_fanout =
151 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
152 	if (remain < len_fanout) {
153 		err = got_error(GOT_ERR_BAD_PACKIDX);
154 		goto done;
155 	}
156 	if (p->map)
157 		h->fanout_table = (uint32_t *)(p->map + offset);
158 	else {
159 		h->fanout_table = malloc(len_fanout);
160 		if (h->fanout_table == NULL) {
161 			err = got_error_from_errno("malloc");
162 			goto done;
163 		}
164 		n = read(p->fd, h->fanout_table, len_fanout);
165 		if (n < 0) {
166 			err = got_error_from_errno("read");
167 			goto done;
168 		} else if (n != len_fanout) {
169 			err = got_error(GOT_ERR_BAD_PACKIDX);
170 			goto done;
171 		}
172 	}
173 	err = verify_fanout_table(h->fanout_table);
174 	if (err)
175 		goto done;
176 	if (verify)
177 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
178 	offset += len_fanout;
179 	remain -= len_fanout;
180 
181 	nobj = be32toh(h->fanout_table[0xff]);
182 	len_ids = nobj * sizeof(*h->sorted_ids);
183 	if (len_ids <= nobj || len_ids > remain) {
184 		err = got_error(GOT_ERR_BAD_PACKIDX);
185 		goto done;
186 	}
187 	if (p->map)
188 		h->sorted_ids =
189 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
190 	else {
191 		h->sorted_ids = malloc(len_ids);
192 		if (h->sorted_ids == NULL) {
193 			err = got_error(GOT_ERR_BAD_PACKIDX);
194 			goto done;
195 		}
196 		n = read(p->fd, h->sorted_ids, len_ids);
197 		if (n < 0)
198 			err = got_error_from_errno("read");
199 		else if (n != len_ids) {
200 			err = got_error(GOT_ERR_BAD_PACKIDX);
201 			goto done;
202 		}
203 	}
204 	if (verify)
205 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
206 	offset += len_ids;
207 	remain -= len_ids;
208 
209 	if (remain < nobj * sizeof(*h->crc32)) {
210 		err = got_error(GOT_ERR_BAD_PACKIDX);
211 		goto done;
212 	}
213 	if (p->map)
214 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
215 	else {
216 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
217 		if (h->crc32 == NULL) {
218 			err = got_error_from_errno("malloc");
219 			goto done;
220 		}
221 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
222 		if (n < 0)
223 			err = got_error_from_errno("read");
224 		else if (n != nobj * sizeof(*h->crc32)) {
225 			err = got_error(GOT_ERR_BAD_PACKIDX);
226 			goto done;
227 		}
228 	}
229 	if (verify)
230 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
231 	remain -= nobj * sizeof(*h->crc32);
232 	offset += nobj * sizeof(*h->crc32);
233 
234 	if (remain < nobj * sizeof(*h->offsets)) {
235 		err = got_error(GOT_ERR_BAD_PACKIDX);
236 		goto done;
237 	}
238 	if (p->map)
239 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
240 	else {
241 		h->offsets = malloc(nobj * sizeof(*h->offsets));
242 		if (h->offsets == NULL) {
243 			err = got_error_from_errno("malloc");
244 			goto done;
245 		}
246 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
247 		if (n < 0)
248 			err = got_error_from_errno("read");
249 		else if (n != nobj * sizeof(*h->offsets)) {
250 			err = got_error(GOT_ERR_BAD_PACKIDX);
251 			goto done;
252 		}
253 	}
254 	if (verify)
255 		SHA1Update(&ctx, (uint8_t *)h->offsets,
256 		    nobj * sizeof(*h->offsets));
257 	remain -= nobj * sizeof(*h->offsets);
258 	offset += nobj * sizeof(*h->offsets);
259 
260 	/* Large file offsets are contained only in files > 2GB. */
261 	if (verify || packfile_size > 0x7fffffff) {
262 		for (i = 0; i < nobj; i++) {
263 			uint32_t o = h->offsets[i];
264 			if (o & htobe32(GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX))
265 				p->nlargeobj++;
266 		}
267 	}
268 	if (p->nlargeobj == 0)
269 		goto checksum;
270 	else if (packfile_size <= 0x7fffffff) {
271 		err = got_error(GOT_ERR_BAD_PACKIDX);
272 		goto done;
273 	}
274 
275 	if (remain < p->nlargeobj * sizeof(*h->large_offsets)) {
276 		err = got_error(GOT_ERR_BAD_PACKIDX);
277 		goto done;
278 	}
279 	if (p->map)
280 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
281 	else {
282 		h->large_offsets = malloc(p->nlargeobj *
283 		    sizeof(*h->large_offsets));
284 		if (h->large_offsets == NULL) {
285 			err = got_error_from_errno("malloc");
286 			goto done;
287 		}
288 		n = read(p->fd, h->large_offsets,
289 		    p->nlargeobj * sizeof(*h->large_offsets));
290 		if (n < 0)
291 			err = got_error_from_errno("read");
292 		else if (n != p->nlargeobj * sizeof(*h->large_offsets)) {
293 			err = got_error(GOT_ERR_BAD_PACKIDX);
294 			goto done;
295 		}
296 	}
297 	if (verify)
298 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
299 		    p->nlargeobj * sizeof(*h->large_offsets));
300 	remain -= p->nlargeobj * sizeof(*h->large_offsets);
301 	offset += p->nlargeobj * sizeof(*h->large_offsets);
302 
303 checksum:
304 	if (remain < sizeof(*h->trailer)) {
305 		err = got_error(GOT_ERR_BAD_PACKIDX);
306 		goto done;
307 	}
308 	if (p->map)
309 		h->trailer =
310 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
311 	else {
312 		h->trailer = malloc(sizeof(*h->trailer));
313 		if (h->trailer == NULL) {
314 			err = got_error_from_errno("malloc");
315 			goto done;
316 		}
317 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
318 		if (n < 0)
319 			err = got_error_from_errno("read");
320 		else if (n != sizeof(*h->trailer)) {
321 			err = got_error(GOT_ERR_BAD_PACKIDX);
322 			goto done;
323 		}
324 	}
325 	if (verify) {
326 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
327 		SHA1Final(sha1, &ctx);
328 		if (memcmp(h->trailer->packidx_sha1, sha1,
329 		    SHA1_DIGEST_LENGTH) != 0)
330 			err = got_error(GOT_ERR_PACKIDX_CSUM);
331 	}
332 done:
333 	return err;
334 }
335 
336 const struct got_error *
337 got_packidx_open(struct got_packidx **packidx,
338     int dir_fd, const char *relpath, int verify)
339 {
340 	const struct got_error *err = NULL;
341 	struct got_packidx *p = NULL;
342 	char *pack_relpath;
343 	struct stat idx_sb, pack_sb;
344 
345 	*packidx = NULL;
346 
347 	err = got_packidx_get_packfile_path(&pack_relpath, relpath);
348 	if (err)
349 		return err;
350 
351 	/*
352 	 * Ensure that a corresponding pack file exists.
353 	 * Some Git repositories have this problem. Git seems to ignore
354 	 * the existence of lonely pack index files but we do not.
355 	 */
356 	if (fstatat(dir_fd, pack_relpath, &pack_sb, 0) == -1) {
357 		if (errno == ENOENT) {
358 			err = got_error_fmt(GOT_ERR_LONELY_PACKIDX,
359 			    "%s", relpath);
360 		} else
361 			err = got_error_from_errno2("fstatat", pack_relpath);
362 		goto done;
363 	}
364 
365 	p = calloc(1, sizeof(*p));
366 	if (p == NULL) {
367 		err = got_error_from_errno("calloc");
368 		goto done;
369 	}
370 
371 	p->fd = openat(dir_fd, relpath, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
372 	if (p->fd == -1) {
373 		err = got_error_from_errno2("openat", relpath);
374 		goto done;
375 	}
376 
377 	if (fstat(p->fd, &idx_sb) != 0) {
378 		err = got_error_from_errno2("fstat", relpath);
379 		goto done;
380 	}
381 	p->len = idx_sb.st_size;
382 	if (p->len < sizeof(p->hdr)) {
383 		err = got_error(GOT_ERR_BAD_PACKIDX);
384 		goto done;
385 	}
386 
387 	p->path_packidx = strdup(relpath);
388 	if (p->path_packidx == NULL) {
389 		err = got_error_from_errno("strdup");
390 		goto done;
391 	}
392 
393 #ifndef GOT_PACK_NO_MMAP
394 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
395 	if (p->map == MAP_FAILED) {
396 		if (errno != ENOMEM) {
397 			err = got_error_from_errno("mmap");
398 			goto done;
399 		}
400 		p->map = NULL; /* fall back to read(2) */
401 	}
402 #endif
403 
404 	err = got_packidx_init_hdr(p, verify, pack_sb.st_size);
405 done:
406 	if (err) {
407 		if (p)
408 			got_packidx_close(p);
409 	} else
410 		*packidx = p;
411 	free(pack_relpath);
412 	return err;
413 }
414 
415 const struct got_error *
416 got_packidx_close(struct got_packidx *packidx)
417 {
418 	const struct got_error *err = NULL;
419 
420 	free(packidx->path_packidx);
421 	if (packidx->map) {
422 		if (munmap(packidx->map, packidx->len) == -1)
423 			err = got_error_from_errno("munmap");
424 	} else {
425 		free(packidx->hdr.magic);
426 		free(packidx->hdr.version);
427 		free(packidx->hdr.fanout_table);
428 		free(packidx->hdr.sorted_ids);
429 		free(packidx->hdr.crc32);
430 		free(packidx->hdr.offsets);
431 		free(packidx->hdr.large_offsets);
432 		free(packidx->hdr.trailer);
433 	}
434 	if (close(packidx->fd) == -1 && err == NULL)
435 		err = got_error_from_errno("close");
436 	free(packidx->sorted_offsets);
437 	free(packidx->sorted_large_offsets);
438 	free(packidx);
439 
440 	return err;
441 }
442 
443 const struct got_error *
444 got_packidx_get_packfile_path(char **path_packfile, const char *path_packidx)
445 {
446 	size_t size;
447 
448 	/* Packfile path contains ".pack" instead of ".idx", so add one byte. */
449 	size = strlen(path_packidx) + 2;
450 	if (size < GOT_PACKFILE_NAMELEN + 1)
451 		return got_error_path(path_packidx, GOT_ERR_BAD_PATH);
452 
453 	*path_packfile = malloc(size);
454 	if (*path_packfile == NULL)
455 		return got_error_from_errno("malloc");
456 
457 	/* Copy up to and excluding ".idx". */
458 	if (strlcpy(*path_packfile, path_packidx,
459 	    size - strlen(GOT_PACKIDX_SUFFIX) - 1) >= size)
460 		return got_error(GOT_ERR_NO_SPACE);
461 
462 	if (strlcat(*path_packfile, GOT_PACKFILE_SUFFIX, size) >= size)
463 		return got_error(GOT_ERR_NO_SPACE);
464 
465 	return NULL;
466 }
467 
468 off_t
469 got_packidx_get_object_offset(struct got_packidx *packidx, int idx)
470 {
471 	uint32_t offset = be32toh(packidx->hdr.offsets[idx]);
472 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
473 		uint64_t loffset;
474 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
475 		if (idx < 0 || idx >= packidx->nlargeobj ||
476 		    packidx->hdr.large_offsets == NULL)
477 			return -1;
478 		loffset = be64toh(packidx->hdr.large_offsets[idx]);
479 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
480 	}
481 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
482 }
483 
484 int
485 got_packidx_get_object_idx(struct got_packidx *packidx,
486     struct got_object_id *id)
487 {
488 	u_int8_t id0 = id->sha1[0];
489 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
490 	int left = 0, right = totobj - 1;
491 
492 	if (id0 > 0)
493 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
494 
495 	while (left <= right) {
496 		struct got_packidx_object_id *oid;
497 		int i, cmp;
498 
499 		i = ((left + right) / 2);
500 		oid = &packidx->hdr.sorted_ids[i];
501 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
502 		if (cmp == 0)
503 			return i;
504 		else if (cmp > 0)
505 			left = i + 1;
506 		else if (cmp < 0)
507 			right = i - 1;
508 	}
509 
510 	return -1;
511 }
512 
513 static int
514 offset_cmp(const void *pa, const void *pb)
515 {
516 	const struct got_pack_offset_index *a, *b;
517 
518 	a = (const struct got_pack_offset_index *)pa;
519 	b = (const struct got_pack_offset_index *)pb;
520 
521 	if (a->offset < b->offset)
522 		return -1;
523 	else if (a->offset > b->offset)
524 		return 1;
525 
526 	return 0;
527 }
528 
529 static int
530 large_offset_cmp(const void *pa, const void *pb)
531 {
532 	const struct got_pack_large_offset_index *a, *b;
533 
534 	a = (const struct got_pack_large_offset_index *)pa;
535 	b = (const struct got_pack_large_offset_index *)pb;
536 
537 	if (a->offset < b->offset)
538 		return -1;
539 	else if (a->offset > b->offset)
540 		return 1;
541 
542 	return 0;
543 }
544 
545 static const struct got_error *
546 build_offset_index(struct got_packidx *p)
547 {
548 	uint32_t nobj = be32toh(p->hdr.fanout_table[0xff]);
549 	unsigned int i, j, k;
550 
551 	p->sorted_offsets = calloc(nobj - p->nlargeobj,
552 	    sizeof(p->sorted_offsets[0]));
553 	if (p->sorted_offsets == NULL)
554 		return got_error_from_errno("calloc");
555 
556 	if (p->nlargeobj > 0) {
557 		p->sorted_large_offsets = calloc(p->nlargeobj,
558 		    sizeof(p->sorted_large_offsets[0]));
559 		if (p->sorted_large_offsets == NULL)
560 			return got_error_from_errno("calloc");
561 	}
562 
563 	j = 0;
564 	k = 0;
565 	for (i = 0; i < nobj; i++) {
566 		uint32_t offset = be32toh(p->hdr.offsets[i]);
567 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
568 			uint64_t loffset;
569 			uint32_t idx;
570 			idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
571 			if (idx >= p->nlargeobj ||
572 			    p->nlargeobj == 0 ||
573 			    p->hdr.large_offsets == NULL)
574 				return got_error(GOT_ERR_BAD_PACKIDX);
575 			loffset = be64toh(p->hdr.large_offsets[idx]);
576 			p->sorted_large_offsets[j].offset = loffset;
577 			p->sorted_large_offsets[j].idx = i;
578 			j++;
579 		} else {
580 			p->sorted_offsets[k].offset = offset;
581 			p->sorted_offsets[k].idx = i;
582 			k++;
583 		}
584 	}
585 	if (j != p->nlargeobj || k != nobj - p->nlargeobj)
586 		return got_error(GOT_ERR_BAD_PACKIDX);
587 
588 	qsort(p->sorted_offsets, nobj - p->nlargeobj,
589 	    sizeof(p->sorted_offsets[0]), offset_cmp);
590 
591 	if (p->sorted_large_offsets)
592 		qsort(p->sorted_large_offsets, p->nlargeobj,
593 		    sizeof(p->sorted_large_offsets[0]), large_offset_cmp);
594 
595 	return NULL;
596 }
597 
598 const struct got_error *
599 got_packidx_get_offset_idx(int *idx, struct got_packidx *packidx, off_t offset)
600 {
601 	const struct got_error *err;
602 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
603 	int i, left, right;
604 
605 	*idx = -1;
606 
607 	if (packidx->sorted_offsets == NULL) {
608 		err = build_offset_index(packidx);
609 		if (err)
610 			return err;
611 	}
612 
613 	if (offset >= 0x7fffffff) {
614 		uint64_t lo;
615 		left = 0, right = packidx->nlargeobj - 1;
616 		while (left <= right) {
617 			i = ((left + right) / 2);
618 			lo = packidx->sorted_large_offsets[i].offset;
619 			if (lo == offset) {
620 				*idx = packidx->sorted_large_offsets[i].idx;
621 				break;
622 			} else if (offset > lo)
623 				left = i + 1;
624 			else if (offset < lo)
625 				right = i - 1;
626 		}
627 	} else {
628 		uint32_t o;
629 		left = 0, right = totobj - packidx->nlargeobj - 1;
630 		while (left <= right) {
631 			i = ((left + right) / 2);
632 			o = packidx->sorted_offsets[i].offset;
633 			if (o == offset) {
634 				*idx = packidx->sorted_offsets[i].idx;
635 				break;
636 			} else if (offset > o)
637 				left = i + 1;
638 			else if (offset < o)
639 				right = i - 1;
640 		}
641 	}
642 
643 	return NULL;
644 }
645 
646 const struct got_error *
647 got_packidx_get_object_id(struct got_object_id *id,
648     struct got_packidx *packidx, int idx)
649 {
650 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
651 	struct got_packidx_object_id *oid;
652 
653 	if (idx < 0 || idx >= totobj)
654 		return got_error(GOT_ERR_NO_OBJ);
655 
656 	oid = &packidx->hdr.sorted_ids[idx];
657 	memcpy(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
658 	return NULL;
659 }
660 
661 const struct got_error *
662 got_packidx_match_id_str_prefix(struct got_object_id_queue *matched_ids,
663     struct got_packidx *packidx, const char *id_str_prefix)
664 {
665 	const struct got_error *err = NULL;
666 	u_int8_t id0;
667 	uint32_t totobj = be32toh(packidx->hdr.fanout_table[0xff]);
668 	char hex[3];
669 	size_t prefix_len = strlen(id_str_prefix);
670 	struct got_packidx_object_id *oid;
671 	uint32_t i = 0;
672 
673 	STAILQ_INIT(matched_ids);
674 
675 	if (prefix_len < 2)
676 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
677 
678 	hex[0] = id_str_prefix[0];
679 	hex[1] = id_str_prefix[1];
680 	hex[2] = '\0';
681 	if (!got_parse_xdigit(&id0, hex))
682 		return got_error_path(id_str_prefix, GOT_ERR_BAD_OBJ_ID_STR);
683 
684 	if (id0 > 0)
685 		i = be32toh(packidx->hdr.fanout_table[id0 - 1]);
686 	oid = &packidx->hdr.sorted_ids[i];
687 	while (i < totobj && oid->sha1[0] == id0) {
688 		char id_str[SHA1_DIGEST_STRING_LENGTH];
689 		struct got_object_qid *qid;
690 		int cmp;
691 
692 		if (!got_sha1_digest_to_str(oid->sha1, id_str, sizeof(id_str)))
693 		        return got_error(GOT_ERR_NO_SPACE);
694 
695 		cmp = strncmp(id_str, id_str_prefix, prefix_len);
696 		if (cmp < 0) {
697 			oid = &packidx->hdr.sorted_ids[++i];
698 			continue;
699 		} else if (cmp > 0)
700 			break;
701 
702 		err = got_object_qid_alloc_partial(&qid);
703 		if (err)
704 			break;
705 		memcpy(qid->id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
706 		STAILQ_INSERT_TAIL(matched_ids, qid, entry);
707 
708 		oid = &packidx->hdr.sorted_ids[++i];
709 	}
710 
711 	if (err)
712 		got_object_id_queue_free(matched_ids);
713 	return err;
714 }
715 
716 static const struct got_error *
717 pack_stop_privsep_child(struct got_pack *pack)
718 {
719 	const struct got_error *err = NULL;
720 
721 	if (pack->privsep_child == NULL)
722 		return NULL;
723 
724 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
725 	if (err)
726 		return err;
727 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
728 	if (close(pack->privsep_child->imsg_fd) == -1 && err == NULL)
729 		err = got_error_from_errno("close");
730 	free(pack->privsep_child->ibuf);
731 	free(pack->privsep_child);
732 	pack->privsep_child = NULL;
733 	return err;
734 }
735 
736 const struct got_error *
737 got_pack_close(struct got_pack *pack)
738 {
739 	const struct got_error *err = NULL;
740 
741 	err = pack_stop_privsep_child(pack);
742 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
743 		err = got_error_from_errno("munmap");
744 	if (pack->fd != -1 && close(pack->fd) == -1 && err == NULL)
745 		err = got_error_from_errno("close");
746 	pack->fd = -1;
747 	free(pack->path_packfile);
748 	pack->path_packfile = NULL;
749 	pack->filesize = 0;
750 	if (pack->delta_cache) {
751 		got_delta_cache_free(pack->delta_cache);
752 		pack->delta_cache = NULL;
753 	}
754 
755 	return err;
756 }
757 
758 const struct got_error *
759 got_pack_parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
760     struct got_pack *pack, off_t offset)
761 {
762 	uint8_t t = 0;
763 	uint64_t s = 0;
764 	uint8_t sizeN;
765 	size_t mapoff = 0;
766 	int i = 0;
767 
768 	*len = 0;
769 
770 	if (offset >= pack->filesize)
771 		return got_error(GOT_ERR_PACK_OFFSET);
772 
773 	if (pack->map) {
774 		mapoff = (size_t)offset;
775 	} else {
776 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
777 			return got_error_from_errno("lseek");
778 	}
779 
780 	do {
781 		/* We do not support size values which don't fit in 64 bit. */
782 		if (i > 9)
783 			return got_error(GOT_ERR_NO_SPACE);
784 
785 		if (pack->map) {
786 			if (mapoff + sizeof(sizeN) >= pack->filesize)
787 				return got_error(GOT_ERR_BAD_PACKFILE);
788 			sizeN = *(pack->map + mapoff);
789 			mapoff += sizeof(sizeN);
790 		} else {
791 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
792 			if (n < 0)
793 				return got_error_from_errno("read");
794 			if (n != sizeof(sizeN))
795 				return got_error(GOT_ERR_BAD_PACKFILE);
796 		}
797 		*len += sizeof(sizeN);
798 
799 		if (i == 0) {
800 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
801 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
802 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
803 		} else {
804 			size_t shift = 4 + 7 * (i - 1);
805 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
806 		}
807 		i++;
808 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
809 
810 	*type = t;
811 	*size = s;
812 	return NULL;
813 }
814 
815 static const struct got_error *
816 open_plain_object(struct got_object **obj, struct got_object_id *id,
817     uint8_t type, off_t offset, size_t size, int idx)
818 {
819 	*obj = calloc(1, sizeof(**obj));
820 	if (*obj == NULL)
821 		return got_error_from_errno("calloc");
822 
823 	(*obj)->type = type;
824 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
825 	(*obj)->pack_idx = idx;
826 	(*obj)->hdrlen = 0;
827 	(*obj)->size = size;
828 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
829 	(*obj)->pack_offset = offset;
830 
831 	return NULL;
832 }
833 
834 static const struct got_error *
835 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
836     off_t delta_offset)
837 {
838 	int64_t o = 0;
839 	uint8_t offN;
840 	int i = 0;
841 
842 	*offset = 0;
843 	*len = 0;
844 
845 	do {
846 		/* We do not support offset values which don't fit in 64 bit. */
847 		if (i > 8)
848 			return got_error(GOT_ERR_NO_SPACE);
849 
850 		if (pack->map) {
851 			size_t mapoff;
852 			mapoff = (size_t)delta_offset + *len;
853 			if (mapoff + sizeof(offN) >= pack->filesize)
854 				return got_error(GOT_ERR_PACK_OFFSET);
855 			offN = *(pack->map + mapoff);
856 		} else {
857 			ssize_t n;
858 			n = read(pack->fd, &offN, sizeof(offN));
859 			if (n < 0)
860 				return got_error_from_errno("read");
861 			if (n != sizeof(offN))
862 				return got_error(GOT_ERR_BAD_PACKFILE);
863 		}
864 		*len += sizeof(offN);
865 
866 		if (i == 0)
867 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
868 		else {
869 			o++;
870 			o <<= 7;
871 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
872 		}
873 		i++;
874 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
875 
876 	*offset = o;
877 	return NULL;
878 }
879 
880 const struct got_error *
881 got_pack_parse_offset_delta(off_t *base_offset, size_t *len,
882     struct got_pack *pack, off_t offset, int tslen)
883 {
884 	const struct got_error *err;
885 	int64_t negoffset;
886 	size_t negofflen;
887 
888 	*len = 0;
889 
890 	err = parse_negative_offset(&negoffset, &negofflen, pack,
891 	    offset + tslen);
892 	if (err)
893 		return err;
894 
895 	/* Compute the base object's offset (must be in the same pack file). */
896 	*base_offset = (offset - negoffset);
897 	if (*base_offset <= 0)
898 		return got_error(GOT_ERR_BAD_PACKFILE);
899 
900 	*len = negofflen;
901 	return NULL;
902 }
903 
904 static const struct got_error *
905 read_delta_data(uint8_t **delta_buf, size_t *delta_len,
906     size_t delta_data_offset, struct got_pack *pack)
907 {
908 	const struct got_error *err = NULL;
909 
910 	if (pack->map) {
911 		if (delta_data_offset >= pack->filesize)
912 			return got_error(GOT_ERR_PACK_OFFSET);
913 		err = got_inflate_to_mem_mmap(delta_buf, delta_len,
914 		    NULL, NULL, pack->map, delta_data_offset,
915 		    pack->filesize - delta_data_offset);
916 	} else {
917 		if (lseek(pack->fd, delta_data_offset, SEEK_SET) == -1)
918 			return got_error_from_errno("lseek");
919 		err = got_inflate_to_mem_fd(delta_buf, delta_len, NULL,
920 		    NULL, 0, pack->fd);
921 	}
922 	return err;
923 }
924 
925 static const struct got_error *
926 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
927     int delta_type, size_t delta_size, size_t delta_data_offset)
928 {
929 	struct got_delta *delta;
930 
931 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
932 	    delta_data_offset);
933 	if (delta == NULL)
934 		return got_error_from_errno("got_delta_open");
935 	/* delta is freed in got_object_close() */
936 	deltas->nentries++;
937 	STAILQ_INSERT_HEAD(&deltas->entries, delta, entry);
938 	return NULL;
939 }
940 
941 static const struct got_error *
942 resolve_offset_delta(struct got_delta_chain *deltas,
943     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
944     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
945 
946 {
947 	const struct got_error *err;
948 	off_t base_offset;
949 	uint8_t base_type;
950 	uint64_t base_size;
951 	size_t base_tslen;
952 	off_t delta_data_offset;
953 	size_t consumed;
954 
955 	err = got_pack_parse_offset_delta(&base_offset, &consumed, pack,
956 	    delta_offset, tslen);
957 	if (err)
958 		return err;
959 
960 	delta_data_offset = delta_offset + tslen + consumed;
961 	if (delta_data_offset >= pack->filesize)
962 		return got_error(GOT_ERR_PACK_OFFSET);
963 
964 	if (pack->map == NULL) {
965 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
966 		if (delta_data_offset == -1)
967 			return got_error_from_errno("lseek");
968 	}
969 
970 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
971 	    delta_data_offset);
972 	if (err)
973 		return err;
974 
975 	/* An offset delta must be in the same packfile. */
976 	if (base_offset >= pack->filesize)
977 		return got_error(GOT_ERR_PACK_OFFSET);
978 
979 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
980 	    &base_tslen, pack, base_offset);
981 	if (err)
982 		return err;
983 
984 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
985 	    base_tslen, base_type, base_size, recursion - 1);
986 }
987 
988 const struct got_error *
989 got_pack_parse_ref_delta(struct got_object_id *id,
990     struct got_pack *pack, off_t delta_offset, int tslen)
991 {
992 	if (pack->map) {
993 		size_t mapoff = delta_offset + tslen;
994 		if (mapoff + sizeof(*id) >= pack->filesize)
995 			return got_error(GOT_ERR_PACK_OFFSET);
996 		memcpy(id, pack->map + mapoff, sizeof(*id));
997 	} else {
998 		ssize_t n;
999 		n = read(pack->fd, id, sizeof(*id));
1000 		if (n < 0)
1001 			return got_error_from_errno("read");
1002 		if (n != sizeof(*id))
1003 			return got_error(GOT_ERR_BAD_PACKFILE);
1004 	}
1005 
1006 	return NULL;
1007 }
1008 
1009 static const struct got_error *
1010 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
1011     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
1012     size_t delta_size, unsigned int recursion)
1013 {
1014 	const struct got_error *err;
1015 	struct got_object_id id;
1016 	int idx;
1017 	off_t base_offset;
1018 	uint8_t base_type;
1019 	uint64_t base_size;
1020 	size_t base_tslen;
1021 	off_t delta_data_offset;
1022 
1023 	if (delta_offset + tslen >= pack->filesize)
1024 		return got_error(GOT_ERR_PACK_OFFSET);
1025 
1026 	err = got_pack_parse_ref_delta(&id, pack, delta_offset, tslen);
1027 	if (err)
1028 		return err;
1029 	if (pack->map) {
1030 		delta_data_offset = delta_offset + tslen + sizeof(id);
1031 	} else {
1032 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
1033 		if (delta_data_offset == -1)
1034 			return got_error_from_errno("lseek");
1035 	}
1036 
1037 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
1038 	    delta_data_offset);
1039 	if (err)
1040 		return err;
1041 
1042 	/* Delta base must be in the same pack file. */
1043 	idx = got_packidx_get_object_idx(packidx, &id);
1044 	if (idx == -1)
1045 		return got_error(GOT_ERR_NO_OBJ);
1046 
1047 	base_offset = got_packidx_get_object_offset(packidx, idx);
1048 	if (base_offset == (uint64_t)-1)
1049 		return got_error(GOT_ERR_BAD_PACKIDX);
1050 
1051 	if (base_offset >= pack->filesize)
1052 		return got_error(GOT_ERR_PACK_OFFSET);
1053 
1054 	err = got_pack_parse_object_type_and_size(&base_type, &base_size,
1055 	    &base_tslen, pack, base_offset);
1056 	if (err)
1057 		return err;
1058 
1059 	return got_pack_resolve_delta_chain(deltas, packidx, pack, base_offset,
1060 	    base_tslen, base_type, base_size, recursion - 1);
1061 }
1062 
1063 const struct got_error *
1064 got_pack_resolve_delta_chain(struct got_delta_chain *deltas,
1065     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
1066     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
1067 {
1068 	const struct got_error *err = NULL;
1069 
1070 	if (--recursion == 0)
1071 		return got_error(GOT_ERR_RECURSION);
1072 
1073 	switch (delta_type) {
1074 	case GOT_OBJ_TYPE_COMMIT:
1075 	case GOT_OBJ_TYPE_TREE:
1076 	case GOT_OBJ_TYPE_BLOB:
1077 	case GOT_OBJ_TYPE_TAG:
1078 		/* Plain types are the final delta base. Recursion ends. */
1079 		err = add_delta(deltas, delta_offset, tslen, delta_type,
1080 		    delta_size, 0);
1081 		break;
1082 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1083 		err = resolve_offset_delta(deltas, packidx, pack,
1084 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1085 		break;
1086 	case GOT_OBJ_TYPE_REF_DELTA:
1087 		err = resolve_ref_delta(deltas, packidx, pack,
1088 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
1089 		break;
1090 	default:
1091 		return got_error(GOT_ERR_OBJ_TYPE);
1092 	}
1093 
1094 	return err;
1095 }
1096 
1097 static const struct got_error *
1098 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
1099     struct got_pack *pack, struct got_object_id *id, off_t offset,
1100     size_t tslen, int delta_type, size_t delta_size, int idx)
1101 {
1102 	const struct got_error *err = NULL;
1103 	int resolved_type;
1104 
1105 	*obj = calloc(1, sizeof(**obj));
1106 	if (*obj == NULL)
1107 		return got_error_from_errno("calloc");
1108 
1109 	(*obj)->flags = 0;
1110 	(*obj)->hdrlen = 0;
1111 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
1112 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
1113 	(*obj)->pack_offset = offset + tslen;
1114 
1115 	STAILQ_INIT(&(*obj)->deltas.entries);
1116 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
1117 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
1118 	(*obj)->pack_idx = idx;
1119 
1120 	err = got_pack_resolve_delta_chain(&(*obj)->deltas, packidx, pack,
1121 	    offset, tslen, delta_type, delta_size,
1122 	    GOT_DELTA_CHAIN_RECURSION_MAX);
1123 	if (err)
1124 		goto done;
1125 
1126 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
1127 	if (err)
1128 		goto done;
1129 	(*obj)->type = resolved_type;
1130 done:
1131 	if (err) {
1132 		got_object_close(*obj);
1133 		*obj = NULL;
1134 	}
1135 	return err;
1136 }
1137 
1138 const struct got_error *
1139 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
1140     struct got_packidx *packidx, int idx, struct got_object_id *id)
1141 {
1142 	const struct got_error *err = NULL;
1143 	off_t offset;
1144 	uint8_t type;
1145 	uint64_t size;
1146 	size_t tslen;
1147 
1148 	*obj = NULL;
1149 
1150 	offset = got_packidx_get_object_offset(packidx, idx);
1151 	if (offset == (uint64_t)-1)
1152 		return got_error(GOT_ERR_BAD_PACKIDX);
1153 
1154 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1155 	    pack, offset);
1156 	if (err)
1157 		return err;
1158 
1159 	switch (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 		err = open_plain_object(obj, id, type, offset + tslen,
1165 		    size, idx);
1166 		break;
1167 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1168 	case GOT_OBJ_TYPE_REF_DELTA:
1169 		err = open_delta_object(obj, packidx, pack, id, offset,
1170 		    tslen, type, size, idx);
1171 		break;
1172 	default:
1173 		err = got_error(GOT_ERR_OBJ_TYPE);
1174 		break;
1175 	}
1176 
1177 	return err;
1178 }
1179 
1180 const struct got_error *
1181 got_pack_get_delta_chain_max_size(uint64_t *max_size,
1182     struct got_delta_chain *deltas, struct got_pack *pack)
1183 {
1184 	struct got_delta *delta;
1185 	uint64_t base_size = 0, result_size = 0;
1186 
1187 	*max_size = 0;
1188 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1189 		/* Plain object types are the delta base. */
1190 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1191 		    delta->type != GOT_OBJ_TYPE_TREE &&
1192 		    delta->type != GOT_OBJ_TYPE_BLOB &&
1193 		    delta->type != GOT_OBJ_TYPE_TAG) {
1194 			const struct got_error *err;
1195 			uint8_t *delta_buf;
1196 			size_t delta_len;
1197 			int cached = 1;
1198 
1199 			got_delta_cache_get(&delta_buf, &delta_len,
1200 			    pack->delta_cache, delta->data_offset);
1201 			if (delta_buf == NULL) {
1202 				cached = 0;
1203 				err = read_delta_data(&delta_buf, &delta_len,
1204 				    delta->data_offset, pack);
1205 				if (err)
1206 					return err;
1207 				err = got_delta_cache_add(pack->delta_cache,
1208 				    delta->data_offset, delta_buf, delta_len);
1209 				if (err == NULL)
1210 					cached = 1;
1211 				else if (err->code != GOT_ERR_NO_SPACE) {
1212 					free(delta_buf);
1213 					return err;
1214 				}
1215 			}
1216 			err = got_delta_get_sizes(&base_size, &result_size,
1217 			    delta_buf, delta_len);
1218 			if (!cached)
1219 				free(delta_buf);
1220 			if (err)
1221 				return err;
1222 		} else
1223 			base_size = delta->size;
1224 		if (base_size > *max_size)
1225 			*max_size = base_size;
1226 		if (result_size > *max_size)
1227 			*max_size = result_size;
1228 	}
1229 
1230 	return NULL;
1231 }
1232 
1233 const struct got_error *
1234 got_pack_get_max_delta_object_size(uint64_t *size, struct got_object *obj,
1235     struct got_pack *pack)
1236 {
1237 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
1238 		return got_error(GOT_ERR_OBJ_TYPE);
1239 
1240 	return got_pack_get_delta_chain_max_size(size, &obj->deltas, pack);
1241 }
1242 
1243 const struct got_error *
1244 got_pack_dump_delta_chain_to_file(size_t *result_size,
1245     struct got_delta_chain *deltas, struct got_pack *pack, FILE *outfile,
1246     FILE *base_file, FILE *accum_file)
1247 {
1248 	const struct got_error *err = NULL;
1249 	struct got_delta *delta;
1250 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1251 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1252 	uint64_t max_size;
1253 	int n = 0;
1254 
1255 	*result_size = 0;
1256 
1257 	if (STAILQ_EMPTY(&deltas->entries))
1258 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1259 
1260 	/* We process small enough files entirely in memory for speed. */
1261 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1262 	if (err)
1263 		return err;
1264 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1265 		accum_buf = malloc(max_size);
1266 		if (accum_buf == NULL)
1267 			return got_error_from_errno("malloc");
1268 		base_file = NULL;
1269 		accum_file = NULL;
1270 	} else {
1271 		if (fseeko(base_file, 0L, SEEK_SET) == -1)
1272 			return got_error_from_errno("fseeko");
1273 		if (fseeko(accum_file, 0L, SEEK_SET) == -1)
1274 			return got_error_from_errno("fseeko");
1275 	}
1276 
1277 	/* Deltas are ordered in ascending order. */
1278 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1279 		int cached = 1;
1280 		if (n == 0) {
1281 			size_t mapoff;
1282 			off_t delta_data_offset;
1283 
1284 			/* Plain object types are the delta base. */
1285 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1286 			    delta->type != GOT_OBJ_TYPE_TREE &&
1287 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1288 			    delta->type != GOT_OBJ_TYPE_TAG) {
1289 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1290 				goto done;
1291 			}
1292 
1293 			delta_data_offset = delta->offset + delta->tslen;
1294 			if (delta_data_offset >= pack->filesize) {
1295 				err = got_error(GOT_ERR_PACK_OFFSET);
1296 				goto done;
1297 			}
1298 			if (pack->map == NULL) {
1299 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1300 				    == -1) {
1301 					err = got_error_from_errno("lseek");
1302 					goto done;
1303 				}
1304 			}
1305 			if (base_file) {
1306 				if (pack->map) {
1307 					mapoff = (size_t)delta_data_offset;
1308 					err = got_inflate_to_file_mmap(
1309 					    &base_bufsz, NULL, NULL, pack->map,
1310 					    mapoff, pack->filesize - mapoff,
1311 					    base_file);
1312 				} else
1313 					err = got_inflate_to_file_fd(
1314 					    &base_bufsz, NULL, NULL, pack->fd,
1315 					    base_file);
1316 			} else {
1317 				if (pack->map) {
1318 					mapoff = (size_t)delta_data_offset;
1319 					err = got_inflate_to_mem_mmap(&base_buf,
1320 					    &base_bufsz, NULL, NULL,
1321 					    pack->map, mapoff,
1322 					    pack->filesize - mapoff);
1323 				} else
1324 					err = got_inflate_to_mem_fd(&base_buf,
1325 					    &base_bufsz, NULL, NULL, max_size,
1326 					    pack->fd);
1327 			}
1328 			if (err)
1329 				goto done;
1330 			n++;
1331 			if (base_file)
1332 				rewind(base_file);
1333 			continue;
1334 		}
1335 
1336 		got_delta_cache_get(&delta_buf, &delta_len,
1337 		    pack->delta_cache, delta->data_offset);
1338 		if (delta_buf == NULL) {
1339 			cached = 0;
1340 			err = read_delta_data(&delta_buf, &delta_len,
1341 			    delta->data_offset, pack);
1342 			if (err)
1343 				goto done;
1344 			err = got_delta_cache_add(pack->delta_cache,
1345 			    delta->data_offset, delta_buf, delta_len);
1346 			if (err == NULL)
1347 				cached = 1;
1348 			else if (err->code != GOT_ERR_NO_SPACE) {
1349 				free(delta_buf);
1350 				goto done;
1351 			}
1352 		}
1353 		if (base_buf) {
1354 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1355 			    delta_buf, delta_len, accum_buf,
1356 			    &accum_size, max_size);
1357 			n++;
1358 		} else {
1359 			err = got_delta_apply(base_file, delta_buf,
1360 			    delta_len,
1361 			    /* Final delta application writes to output file. */
1362 			    ++n < deltas->nentries ? accum_file : outfile,
1363 			    &accum_size);
1364 		}
1365 		if (!cached)
1366 			free(delta_buf);
1367 		if (err)
1368 			goto done;
1369 
1370 		if (n < deltas->nentries) {
1371 			/* Accumulated delta becomes the new base. */
1372 			if (base_buf) {
1373 				uint8_t *tmp = accum_buf;
1374 				/*
1375 				 * Base buffer switches roles with accumulation
1376 				 * buffer. Ensure it can hold the largest
1377 				 * result in the delta chain. The initial
1378 				 * allocation might have been smaller.
1379 				 */
1380 				if (base_bufsz < max_size) {
1381 					uint8_t *p;
1382 					p = reallocarray(base_buf, 1, max_size);
1383 					if (p == NULL) {
1384 						err = got_error_from_errno(
1385 						    "reallocarray");
1386 						goto done;
1387 					}
1388 					base_buf = p;
1389 					base_bufsz = max_size;
1390 				}
1391 				accum_buf = base_buf;
1392 				base_buf = tmp;
1393 			} else {
1394 				FILE *tmp = accum_file;
1395 				accum_file = base_file;
1396 				base_file = tmp;
1397 				rewind(base_file);
1398 				rewind(accum_file);
1399 			}
1400 		}
1401 	}
1402 
1403 done:
1404 	free(base_buf);
1405 	if (accum_buf) {
1406 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1407 		free(accum_buf);
1408 		if (len != accum_size)
1409 			err = got_ferror(outfile, GOT_ERR_IO);
1410 	}
1411 	rewind(outfile);
1412 	if (err == NULL)
1413 		*result_size = accum_size;
1414 	return err;
1415 }
1416 
1417 const struct got_error *
1418 got_pack_dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1419     struct got_delta_chain *deltas, struct got_pack *pack)
1420 {
1421 	const struct got_error *err = NULL;
1422 	struct got_delta *delta;
1423 	uint8_t *base_buf = NULL, *accum_buf = NULL, *delta_buf;
1424 	size_t base_bufsz = 0, accum_size = 0, delta_len;
1425 	uint64_t max_size;
1426 	int n = 0;
1427 
1428 	*outbuf = NULL;
1429 	*outlen = 0;
1430 
1431 	if (STAILQ_EMPTY(&deltas->entries))
1432 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1433 
1434 	err = got_pack_get_delta_chain_max_size(&max_size, deltas, pack);
1435 	if (err)
1436 		return err;
1437 	accum_buf = malloc(max_size);
1438 	if (accum_buf == NULL)
1439 		return got_error_from_errno("malloc");
1440 
1441 	/* Deltas are ordered in ascending order. */
1442 	STAILQ_FOREACH(delta, &deltas->entries, entry) {
1443 		int cached = 1;
1444 		if (n == 0) {
1445 			size_t delta_data_offset;
1446 
1447 			/* Plain object types are the delta base. */
1448 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1449 			    delta->type != GOT_OBJ_TYPE_TREE &&
1450 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1451 			    delta->type != GOT_OBJ_TYPE_TAG) {
1452 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1453 				goto done;
1454 			}
1455 
1456 			delta_data_offset = delta->offset + delta->tslen;
1457 			if (delta_data_offset >= pack->filesize) {
1458 				err = got_error(GOT_ERR_PACK_OFFSET);
1459 				goto done;
1460 			}
1461 			if (pack->map) {
1462 				size_t mapoff = (size_t)delta_data_offset;
1463 				err = got_inflate_to_mem_mmap(&base_buf,
1464 				    &base_bufsz, NULL, NULL, pack->map,
1465 				    mapoff, pack->filesize - mapoff);
1466 			} else {
1467 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1468 				    == -1) {
1469 					err = got_error_from_errno("lseek");
1470 					goto done;
1471 				}
1472 				err = got_inflate_to_mem_fd(&base_buf,
1473 				    &base_bufsz, NULL, NULL, max_size,
1474 				    pack->fd);
1475 			}
1476 			if (err)
1477 				goto done;
1478 			n++;
1479 			continue;
1480 		}
1481 
1482 		got_delta_cache_get(&delta_buf, &delta_len,
1483 		    pack->delta_cache, delta->data_offset);
1484 		if (delta_buf == NULL) {
1485 			cached = 0;
1486 			err = read_delta_data(&delta_buf, &delta_len,
1487 			    delta->data_offset, pack);
1488 			if (err)
1489 				goto done;
1490 			err = got_delta_cache_add(pack->delta_cache,
1491 			    delta->data_offset, delta_buf, delta_len);
1492 			if (err == NULL)
1493 				cached = 1;
1494 			else if (err->code != GOT_ERR_NO_SPACE) {
1495 				free(delta_buf);
1496 				goto done;
1497 			}
1498 		}
1499 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1500 		    delta_buf, delta_len, accum_buf,
1501 		    &accum_size, max_size);
1502 		if (!cached)
1503 			free(delta_buf);
1504 		n++;
1505 		if (err)
1506 			goto done;
1507 
1508 		if (n < deltas->nentries) {
1509 			/* Accumulated delta becomes the new base. */
1510 			uint8_t *tmp = accum_buf;
1511 			/*
1512 			 * Base buffer switches roles with accumulation buffer.
1513 			 * Ensure it can hold the largest result in the delta
1514 			 * chain. Initial allocation might have been smaller.
1515 			 */
1516 			if (base_bufsz < max_size) {
1517 				uint8_t *p;
1518 				p = reallocarray(base_buf, 1, max_size);
1519 				if (p == NULL) {
1520 					err = got_error_from_errno(
1521 					    "reallocarray");
1522 					goto done;
1523 				}
1524 				base_buf = p;
1525 				base_bufsz = max_size;
1526 			}
1527 			accum_buf = base_buf;
1528 			base_buf = tmp;
1529 		}
1530 	}
1531 
1532 done:
1533 	free(base_buf);
1534 	if (err) {
1535 		free(accum_buf);
1536 		*outbuf = NULL;
1537 		*outlen = 0;
1538 	} else {
1539 		*outbuf = accum_buf;
1540 		*outlen = accum_size;
1541 	}
1542 	return err;
1543 }
1544 
1545 const struct got_error *
1546 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1547     FILE *outfile, FILE *base_file, FILE *accum_file)
1548 {
1549 	const struct got_error *err = NULL;
1550 
1551 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1552 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1553 
1554 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1555 		if (obj->pack_offset >= pack->filesize)
1556 			return got_error(GOT_ERR_PACK_OFFSET);
1557 
1558 		if (pack->map) {
1559 			size_t mapoff = (size_t)obj->pack_offset;
1560 			err = got_inflate_to_file_mmap(&obj->size, NULL, NULL,
1561 			    pack->map, mapoff, pack->filesize - mapoff,
1562 			    outfile);
1563 		} else {
1564 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1565 				return got_error_from_errno("lseek");
1566 			err = got_inflate_to_file_fd(&obj->size, NULL, NULL,
1567 			    pack->fd, outfile);
1568 		}
1569 	} else
1570 		err = got_pack_dump_delta_chain_to_file(&obj->size,
1571 		    &obj->deltas, pack, outfile, base_file, accum_file);
1572 
1573 	return err;
1574 }
1575 
1576 const struct got_error *
1577 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1578     struct got_object *obj, struct got_pack *pack)
1579 {
1580 	const struct got_error *err = NULL;
1581 
1582 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1583 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1584 
1585 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1586 		if (obj->pack_offset >= pack->filesize)
1587 			return got_error(GOT_ERR_PACK_OFFSET);
1588 		if (pack->map) {
1589 			size_t mapoff = (size_t)obj->pack_offset;
1590 			err = got_inflate_to_mem_mmap(buf, len, NULL, NULL,
1591 			    pack->map, mapoff, pack->filesize - mapoff);
1592 		} else {
1593 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1594 				return got_error_from_errno("lseek");
1595 			err = got_inflate_to_mem_fd(buf, len, NULL, NULL,
1596 			    obj->size, pack->fd);
1597 		}
1598 	} else
1599 		err = got_pack_dump_delta_chain_to_mem(buf, len, &obj->deltas,
1600 		    pack);
1601 
1602 	return err;
1603 }
1604 
1605 const struct got_error *
1606 got_packfile_extract_raw_delta(uint8_t **delta_buf, size_t *delta_size,
1607     off_t *delta_offset, off_t *base_offset, struct got_object_id *base_id,
1608     uint64_t *base_size, uint64_t *result_size, struct got_pack *pack,
1609     struct got_packidx *packidx, int idx)
1610 {
1611 	const struct got_error *err = NULL;
1612 	off_t offset;
1613 	uint8_t type;
1614 	uint64_t size;
1615 	size_t tslen, delta_hdrlen;
1616 
1617 	*delta_buf = NULL;
1618 	*delta_size = 0;
1619 	*delta_offset = 0;
1620 	*base_offset = 0;
1621 	*base_size = 0;
1622 	*result_size = 0;
1623 
1624 	offset = got_packidx_get_object_offset(packidx, idx);
1625 	if (offset == (uint64_t)-1)
1626 		return got_error(GOT_ERR_BAD_PACKIDX);
1627 
1628 	if (offset >= pack->filesize)
1629 		return got_error(GOT_ERR_PACK_OFFSET);
1630 
1631 	err = got_pack_parse_object_type_and_size(&type, &size, &tslen,
1632 	    pack, offset);
1633 	if (err)
1634 		return err;
1635 
1636 	if (tslen + size < tslen || offset + size < size ||
1637 	    tslen + offset < tslen)
1638 		return got_error(GOT_ERR_PACK_OFFSET);
1639 
1640 	switch (type) {
1641 	case GOT_OBJ_TYPE_OFFSET_DELTA:
1642 		err = got_pack_parse_offset_delta(base_offset, &delta_hdrlen,
1643 		    pack, offset, tslen);
1644 		if (err)
1645 			return err;
1646 		break;
1647 	case GOT_OBJ_TYPE_REF_DELTA:
1648 		err = got_pack_parse_ref_delta(base_id, pack, offset, tslen);
1649 		if (err)
1650 			return err;
1651 		delta_hdrlen = SHA1_DIGEST_LENGTH;
1652 		break;
1653 	default:
1654 		return got_error_fmt(GOT_ERR_OBJ_TYPE,
1655 		    "non-delta object type %d found at offset %llu",
1656 		    type, offset);
1657 	}
1658 
1659 	if (tslen + delta_hdrlen < delta_hdrlen ||
1660 	    offset + delta_hdrlen < delta_hdrlen)
1661 		return got_error(GOT_ERR_BAD_DELTA);
1662 
1663 	err = read_delta_data(delta_buf, delta_size,
1664 	    offset + tslen + delta_hdrlen, pack);
1665 	if (err)
1666 		return err;
1667 
1668 	if (*delta_size != size) {
1669 		err = got_error(GOT_ERR_BAD_DELTA);
1670 		goto done;
1671 	}
1672 
1673 	err = got_delta_get_sizes(base_size, result_size, *delta_buf, size);
1674 	if (err)
1675 		goto done;
1676 
1677 	*delta_offset = offset;
1678 done:
1679 	if (err) {
1680 		free(*delta_buf);
1681 		*delta_buf = NULL;
1682 	}
1683 	return err;
1684 }