1 /*
2  * Copyright (c) 2019 Ori Bernstein <ori@openbsd.org>
3  * Copyright (c) 2020, 2022 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include "got_compat.h"
19 
20 #include <sys/queue.h>
21 #include <sys/stat.h>
22 #include <sys/time.h>
23 #include <sys/types.h>
24 #include <sys/uio.h>
25 #include <sys/mman.h>
26 
27 #include <stdint.h>
28 #include <errno.h>
29 #include <imsg.h>
30 #include <limits.h>
31 #include <signal.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <ctype.h>
36 #include <fcntl.h>
37 #include <unistd.h>
38 #include <zlib.h>
39 #include <err.h>
40 #include <assert.h>
41 #include <dirent.h>
42 
43 #include "got_error.h"
44 #include "got_object.h"
45 
46 #include "got_lib_hash.h"
47 #include "got_lib_delta.h"
48 #include "got_lib_inflate.h"
49 #include "got_lib_object.h"
50 #include "got_lib_object_parse.h"
51 #include "got_lib_object_idset.h"
52 #include "got_lib_privsep.h"
53 #include "got_lib_pack.h"
54 #include "got_lib_ratelimit.h"
55 #include "got_lib_pack_index.h"
56 #include "got_lib_delta_cache.h"
57 
58 struct got_indexed_object {
59 	struct got_object_id id;
60 
61 	/*
62 	 * Has this object been fully resolved?
63 	 * If so, we know its ID, otherwise we don't and 'id' is invalid.
64 	 */
65 	int valid;
66 
67 	/* Offset of type+size field for this object in pack file. */
68 	off_t off;
69 
70 	/* Type+size values parsed from pack file. */
71 	uint8_t type;
72 	uint64_t size;
73 
74 	/* Length of on-disk type+size data. */
75 	size_t tslen;
76 
77 	/* Length of object data following type+size. */
78 	size_t len;
79 
80 	uint32_t crc;
81 
82 	union {
83 		struct {
84 			/* For ref deltas. */
85 			struct got_object_id ref_id;
86 		} ref;
87 		struct {
88 			/* For offset deltas. */
89 			off_t base_offset;
90 			size_t base_offsetlen;
91 		} ofs;
92 	} delta;
93 };
94 
95 static void
96 putbe32(char *b, uint32_t n)
97 {
98 	b[0] = n >> 24;
99 	b[1] = n >> 16;
100 	b[2] = n >> 8;
101 	b[3] = n >> 0;
102 }
103 
104 static const struct got_error *
105 read_checksum(uint32_t *crc, struct got_hash *ctx, int fd, size_t len)
106 {
107 	uint8_t buf[8192];
108 	size_t n;
109 	ssize_t r;
110 
111 	for (n = len; n > 0; n -= r){
112 		r = read(fd, buf, n > sizeof(buf) ? sizeof(buf) : n);
113 		if (r == -1)
114 			return got_error_from_errno("read");
115 		if (r == 0)
116 			break;
117 		if (crc)
118 			*crc = crc32(*crc, buf, r);
119 		if (ctx)
120 			got_hash_update(ctx, buf, r);
121 	}
122 
123 	return NULL;
124 }
125 
126 static const struct got_error *
127 read_file_digest(struct got_hash *ctx, FILE *f, size_t len)
128 {
129 	uint8_t buf[8192];
130 	size_t n, r;
131 
132 	for (n = len; n > 0; n -= r) {
133 		r = fread(buf, 1, n > sizeof(buf) ? sizeof(buf) : n, f);
134 		if (r == 0) {
135 			if (feof(f))
136 				return NULL;
137 			return got_ferror(f, GOT_ERR_IO);
138 		}
139 		got_hash_update(ctx, buf, r);
140 	}
141 
142 	return NULL;
143 }
144 
145 static const struct got_error *
146 read_packed_object(struct got_pack *pack, struct got_indexed_object *obj,
147     FILE *tmpfile, struct got_hash *pack_sha1_ctx)
148 {
149 	const struct got_error *err = NULL;
150 	struct got_hash ctx;
151 	uint8_t *data = NULL;
152 	size_t datalen = 0;
153 	ssize_t n;
154 	char *header;
155 	size_t headerlen;
156 	const char *obj_label;
157 	size_t mapoff = obj->off;
158 	struct got_inflate_checksum csum;
159 
160 	memset(&csum, 0, sizeof(csum));
161 	csum.input_ctx = pack_sha1_ctx;
162 	csum.input_crc = &obj->crc;
163 
164 	err = got_pack_parse_object_type_and_size(&obj->type, &obj->size,
165 	    &obj->tslen, pack, obj->off);
166 	if (err)
167 		return err;
168 
169 	if (pack->map) {
170 		obj->crc = crc32(obj->crc, pack->map + mapoff, obj->tslen);
171 		got_hash_update(pack_sha1_ctx, pack->map + mapoff, obj->tslen);
172 		mapoff += obj->tslen;
173 	} else {
174 		/* XXX Seek back and get the CRC of on-disk type+size bytes. */
175 		if (lseek(pack->fd, obj->off, SEEK_SET) == -1)
176 			return got_error_from_errno("lseek");
177 		err = read_checksum(&obj->crc, pack_sha1_ctx,
178 		    pack->fd, obj->tslen);
179 		if (err)
180 			return err;
181 	}
182 
183 	switch (obj->type) {
184 	case GOT_OBJ_TYPE_BLOB:
185 	case GOT_OBJ_TYPE_COMMIT:
186 	case GOT_OBJ_TYPE_TREE:
187 	case GOT_OBJ_TYPE_TAG:
188 		if (obj->size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
189 			if (fseek(tmpfile, 0L, SEEK_SET) == -1) {
190 				err = got_error_from_errno("fseek");
191 				break;
192 			}
193 			if (pack->map) {
194 				err = got_inflate_to_file_mmap(&datalen,
195 				    &obj->len, &csum, pack->map, mapoff,
196 				    pack->filesize - mapoff, tmpfile);
197 			} else {
198 				err = got_inflate_to_file_fd(&datalen,
199 				    &obj->len, &csum, pack->fd, tmpfile);
200 			}
201 		} else {
202 			if (pack->map) {
203 				err = got_inflate_to_mem_mmap(&data, &datalen,
204 				    &obj->len, &csum, pack->map, mapoff,
205 				    pack->filesize - mapoff);
206 			} else {
207 				err = got_inflate_to_mem_fd(&data, &datalen,
208 				    &obj->len, &csum, obj->size, pack->fd);
209 			}
210 		}
211 		if (err)
212 			break;
213 		got_hash_init(&ctx, GOT_HASH_SHA1);
214 		err = got_object_type_label(&obj_label, obj->type);
215 		if (err) {
216 			free(data);
217 			break;
218 		}
219 		if (asprintf(&header, "%s %lld", obj_label,
220 		    (long long)obj->size) == -1) {
221 			err = got_error_from_errno("asprintf");
222 			free(data);
223 			break;
224 		}
225 		headerlen = strlen(header) + 1;
226 		got_hash_update(&ctx, header, headerlen);
227 		if (obj->size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
228 			err = read_file_digest(&ctx, tmpfile, datalen);
229 			if (err) {
230 				free(header);
231 				free(data);
232 				break;
233 			}
234 		} else
235 			got_hash_update(&ctx, data, datalen);
236 		got_hash_final_object_id(&ctx, &obj->id);
237 		free(header);
238 		free(data);
239 		break;
240 	case GOT_OBJ_TYPE_REF_DELTA:
241 		memset(obj->id.sha1, 0xff, SHA1_DIGEST_LENGTH);
242 		if (pack->map) {
243 			if (mapoff + SHA1_DIGEST_LENGTH >= pack->filesize) {
244 				err = got_error(GOT_ERR_BAD_PACKFILE);
245 				break;
246 			}
247 			if (mapoff + SHA1_DIGEST_LENGTH > SIZE_MAX) {
248 				err = got_error_fmt(GOT_ERR_RANGE,
249 				    "mapoff %lld would overflow size_t",
250 				    (long long)mapoff + SHA1_DIGEST_LENGTH);
251 				break;
252 			}
253 			memcpy(obj->delta.ref.ref_id.sha1, pack->map + mapoff,
254 			    SHA1_DIGEST_LENGTH);
255 			obj->crc = crc32(obj->crc, pack->map + mapoff,
256 			    SHA1_DIGEST_LENGTH);
257 			got_hash_update(pack_sha1_ctx, pack->map + mapoff,
258 			    SHA1_DIGEST_LENGTH);
259 			mapoff += SHA1_DIGEST_LENGTH;
260 			err = got_inflate_to_mem_mmap(NULL, &datalen,
261 			    &obj->len, &csum, pack->map, mapoff,
262 			    pack->filesize - mapoff);
263 			if (err)
264 				break;
265 		} else {
266 			n = read(pack->fd, obj->delta.ref.ref_id.sha1,
267 			    SHA1_DIGEST_LENGTH);
268 			if (n == -1) {
269 				err = got_error_from_errno("read");
270 				break;
271 			}
272 			if (n < sizeof(obj->id)) {
273 				err = got_error(GOT_ERR_BAD_PACKFILE);
274 				break;
275 			}
276 			obj->crc = crc32(obj->crc, obj->delta.ref.ref_id.sha1,
277 			    SHA1_DIGEST_LENGTH);
278 			got_hash_update(pack_sha1_ctx,
279 			    obj->delta.ref.ref_id.sha1, SHA1_DIGEST_LENGTH);
280 			err = got_inflate_to_mem_fd(NULL, &datalen, &obj->len,
281 			    &csum, obj->size, pack->fd);
282 			if (err)
283 				break;
284 		}
285 		obj->len += SHA1_DIGEST_LENGTH;
286 		break;
287 	case GOT_OBJ_TYPE_OFFSET_DELTA:
288 		memset(obj->id.sha1, 0xff, SHA1_DIGEST_LENGTH);
289 		err = got_pack_parse_offset_delta(&obj->delta.ofs.base_offset,
290 		    &obj->delta.ofs.base_offsetlen, pack, obj->off,
291 		    obj->tslen);
292 		if (err)
293 			break;
294 
295 		if (pack->map) {
296 			if (mapoff + obj->delta.ofs.base_offsetlen >=
297 			    pack->filesize) {
298 				err = got_error(GOT_ERR_BAD_PACKFILE);
299 				break;
300 			}
301 
302 			if (mapoff + obj->delta.ofs.base_offsetlen >
303 			    SIZE_MAX) {
304 				err = got_error_fmt(GOT_ERR_RANGE,
305 				    "mapoff %lld would overflow size_t",
306 				    (long long)mapoff
307 				    + obj->delta.ofs.base_offsetlen);
308 			}
309 
310 			obj->crc = crc32(obj->crc, pack->map + mapoff,
311 			    obj->delta.ofs.base_offsetlen);
312 			got_hash_update(pack_sha1_ctx, pack->map + mapoff,
313 			    obj->delta.ofs.base_offsetlen);
314 			mapoff += obj->delta.ofs.base_offsetlen;
315 			err = got_inflate_to_mem_mmap(NULL, &datalen,
316 			    &obj->len, &csum, pack->map, mapoff,
317 			    pack->filesize - mapoff);
318 			if (err)
319 				break;
320 		} else {
321 			/*
322 			 * XXX Seek back and get CRC and SHA1 of on-disk
323 			 * offset bytes.
324 			 */
325 			if (lseek(pack->fd, obj->off + obj->tslen, SEEK_SET)
326 			    == -1) {
327 				err = got_error_from_errno("lseek");
328 				break;
329 			}
330 			err = read_checksum(&obj->crc, pack_sha1_ctx,
331 			    pack->fd, obj->delta.ofs.base_offsetlen);
332 			if (err)
333 				break;
334 
335 			err = got_inflate_to_mem_fd(NULL, &datalen, &obj->len,
336 			    &csum, obj->size, pack->fd);
337 			if (err)
338 				break;
339 		}
340 		obj->len += obj->delta.ofs.base_offsetlen;
341 		break;
342 	default:
343 		err = got_error(GOT_ERR_OBJ_TYPE);
344 		break;
345 	}
346 
347 	return err;
348 }
349 
350 const struct got_error *
351 got_pack_hwrite(int fd, void *buf, int len, struct got_hash *ctx)
352 {
353 	ssize_t w;
354 
355 	got_hash_update(ctx, buf, len);
356 
357 	w = write(fd, buf, len);
358 	if (w == -1)
359 		return got_error_from_errno("write");
360 	if (w != len)
361 		return got_error(GOT_ERR_IO);
362 
363 	return NULL;
364 }
365 
366 static const struct got_error *
367 resolve_deltified_object(struct got_pack *pack, struct got_packidx *packidx,
368     struct got_indexed_object *obj, FILE *tmpfile, FILE *delta_base_file,
369     FILE *delta_accum_file)
370 {
371 	const struct got_error *err = NULL;
372 	struct got_delta_chain deltas;
373 	struct got_delta *delta;
374 	uint8_t *buf = NULL;
375 	size_t len = 0;
376 	struct got_hash ctx;
377 	char *header = NULL;
378 	size_t headerlen;
379 	uint64_t max_size;
380 	int base_obj_type;
381 	const char *obj_label;
382 
383 	deltas.nentries = 0;
384 	STAILQ_INIT(&deltas.entries);
385 
386 	err = got_pack_resolve_delta_chain(&deltas, packidx, pack,
387 	    obj->off, obj->tslen, obj->type, obj->size,
388 	    GOT_DELTA_CHAIN_RECURSION_MAX);
389 	if (err)
390 		goto done;
391 
392 	err = got_pack_get_delta_chain_max_size(&max_size, &deltas, pack);
393 	if (err)
394 		goto done;
395 	if (max_size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
396 		rewind(tmpfile);
397 		rewind(delta_base_file);
398 		rewind(delta_accum_file);
399 		err = got_pack_dump_delta_chain_to_file(&len, &deltas,
400 		    pack, tmpfile, delta_base_file, delta_accum_file);
401 		if (err)
402 			goto done;
403 	} else {
404 		err = got_pack_dump_delta_chain_to_mem(&buf, &len,
405 		    &deltas, pack);
406 	}
407 	if (err)
408 		goto done;
409 
410 	err = got_delta_chain_get_base_type(&base_obj_type, &deltas);
411 	if (err)
412 		goto done;
413 	err = got_object_type_label(&obj_label, base_obj_type);
414 	if (err)
415 		goto done;
416 	if (asprintf(&header, "%s %zd", obj_label, len) == -1) {
417 		err = got_error_from_errno("asprintf");
418 		goto done;
419 	}
420 	headerlen = strlen(header) + 1;
421 	got_hash_init(&ctx, GOT_HASH_SHA1);
422 	got_hash_update(&ctx, header, headerlen);
423 	if (max_size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
424 		err = read_file_digest(&ctx, tmpfile, len);
425 		if (err)
426 			goto done;
427 	} else
428 		got_hash_update(&ctx, buf, len);
429 	got_hash_final_object_id(&ctx, &obj->id);
430 done:
431 	free(buf);
432 	free(header);
433 	while (!STAILQ_EMPTY(&deltas.entries)) {
434 		delta = STAILQ_FIRST(&deltas.entries);
435 		STAILQ_REMOVE_HEAD(&deltas.entries, entry);
436 		free(delta);
437 	}
438 	return err;
439 }
440 
441 /* Determine the slot in the pack index a given object ID should use. */
442 static int
443 find_object_idx(struct got_packidx *packidx, uint8_t *sha1)
444 {
445 	u_int8_t id0 = sha1[0];
446 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
447 	int left = 0, right = nindexed - 1;
448 	int cmp = 0, i = 0;
449 
450 	if (id0 > 0)
451 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
452 
453 	while (left <= right) {
454 		struct got_packidx_object_id *oid;
455 
456 		i = ((left + right) / 2);
457 		oid = &packidx->hdr.sorted_ids[i];
458 
459 		cmp = memcmp(sha1, oid->sha1, SHA1_DIGEST_LENGTH);
460 		if (cmp == 0)
461 			return -1; /* object already indexed */
462 		else if (cmp > 0)
463 			left = i + 1;
464 		else if (cmp < 0)
465 			right = i - 1;
466 	}
467 
468 	return left;
469 }
470 
471 #if 0
472 static void
473 print_packidx(struct got_packidx *packidx)
474 {
475 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
476 	int i;
477 
478 	fprintf(stderr, "object IDs:\n");
479 	for (i = 0; i < nindexed; i++) {
480 		char hex[SHA1_DIGEST_STRING_LENGTH];
481 		got_sha1_digest_to_str(packidx->hdr.sorted_ids[i].sha1,
482 		    hex, sizeof(hex));
483 		fprintf(stderr, "%s\n", hex);
484 	}
485 	fprintf(stderr, "\n");
486 
487 	fprintf(stderr, "object offsets:\n");
488 	for (i = 0; i < nindexed; i++) {
489 		uint32_t offset = be32toh(packidx->hdr.offsets[i]);
490 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
491 			int j = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
492 			fprintf(stderr, "%u -> %llu\n", offset,
493 			    be64toh(packidx->hdr.large_offsets[j]));
494 		} else
495 			fprintf(stderr, "%u\n", offset);
496 	}
497 	fprintf(stderr, "\n");
498 
499 	fprintf(stderr, "fanout table:");
500 	for (i = 0; i <= 0xff; i++)
501 		fprintf(stderr, " %u", be32toh(packidx->hdr.fanout_table[i]));
502 	fprintf(stderr, "\n");
503 }
504 #endif
505 
506 static void
507 add_indexed_object(struct got_packidx *packidx, uint32_t idx,
508     struct got_indexed_object *obj)
509 {
510 	int i;
511 
512 	memcpy(packidx->hdr.sorted_ids[idx].sha1, obj->id.sha1,
513 	    SHA1_DIGEST_LENGTH);
514 	packidx->hdr.crc32[idx] = htobe32(obj->crc);
515 	if (obj->off < GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX)
516 		packidx->hdr.offsets[idx] = htobe32(obj->off);
517 	else {
518 		packidx->hdr.offsets[idx] = htobe32(packidx->nlargeobj |
519 		    GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX);
520 		packidx->hdr.large_offsets[packidx->nlargeobj] =
521 		    htobe64(obj->off);
522 		packidx->nlargeobj++;
523 	}
524 
525 	for (i = obj->id.sha1[0]; i <= 0xff; i++) {
526 		uint32_t n = be32toh(packidx->hdr.fanout_table[i]);
527 		packidx->hdr.fanout_table[i] = htobe32(n + 1);
528 	}
529 }
530 
531 static int
532 indexed_obj_cmp(const void *pa, const void *pb)
533 {
534 	struct got_indexed_object *a, *b;
535 
536 	a = (struct got_indexed_object *)pa;
537 	b = (struct got_indexed_object *)pb;
538 	return got_object_id_cmp(&a->id, &b->id);
539 }
540 
541 static void
542 make_packidx(struct got_packidx *packidx, uint32_t nobj,
543     struct got_indexed_object *objects)
544 {
545 	struct got_indexed_object *obj;
546 	int i;
547 	uint32_t idx = 0;
548 
549 	qsort(objects, nobj, sizeof(struct got_indexed_object),
550 	    indexed_obj_cmp);
551 
552 	memset(packidx->hdr.fanout_table, 0,
553 	    GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS * sizeof(uint32_t));
554 	packidx->nlargeobj = 0;
555 
556 	for (i = 0; i < nobj; i++) {
557 		obj = &objects[i];
558 		if (obj->valid)
559 			add_indexed_object(packidx, idx++, obj);
560 	}
561 }
562 
563 static void
564 update_packidx(struct got_packidx *packidx, uint32_t nobj,
565     struct got_indexed_object *obj)
566 {
567 	int idx;
568 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
569 
570 	idx = find_object_idx(packidx, obj->id.sha1);
571 	if (idx == -1)
572 		return; /* object already indexed */
573 
574 	memmove(&packidx->hdr.sorted_ids[idx + 1],
575 	    &packidx->hdr.sorted_ids[idx],
576 	    sizeof(struct got_packidx_object_id) * (nindexed - idx));
577 	memmove(&packidx->hdr.offsets[idx + 1], &packidx->hdr.offsets[idx],
578 	    sizeof(uint32_t) * (nindexed - idx));
579 
580 	add_indexed_object(packidx, idx, obj);
581 }
582 
583 static const struct got_error *
584 report_progress(uint32_t nobj_total, uint32_t nobj_indexed, uint32_t nobj_loose,
585     uint32_t nobj_resolved, struct got_ratelimit *rl,
586     got_pack_index_progress_cb progress_cb, void *progress_arg)
587 {
588 	const struct got_error *err;
589 	int elapsed = 0;
590 
591 	if (rl) {
592 		err = got_ratelimit_check(&elapsed, rl);
593 		if (err || !elapsed)
594 			return err;
595 	}
596 
597 	return progress_cb(progress_arg, nobj_total, nobj_indexed, nobj_loose,
598 	    nobj_resolved);
599 }
600 
601 const struct got_error *
602 got_pack_index(struct got_pack *pack, int idxfd, FILE *tmpfile,
603     FILE *delta_base_file, FILE *delta_accum_file, uint8_t *pack_sha1_expected,
604     got_pack_index_progress_cb progress_cb, void *progress_arg,
605     struct got_ratelimit *rl)
606 {
607 	const struct got_error *err;
608 	struct got_packfile_hdr hdr;
609 	struct got_packidx packidx;
610 	char buf[8];
611 	char pack_sha1[SHA1_DIGEST_LENGTH];
612 	uint32_t nobj, nvalid, nloose, nresolved = 0, i;
613 	struct got_indexed_object *objects = NULL, *obj;
614 	struct got_hash ctx;
615 	uint8_t packidx_hash[SHA1_DIGEST_LENGTH];
616 	ssize_t r, w;
617 	int pass, have_ref_deltas = 0, first_delta_idx = -1;
618 	size_t mapoff = 0;
619 	int p_indexed = 0, last_p_indexed = -1;
620 	int p_resolved = 0, last_p_resolved = -1;
621 
622 	/* Require that pack file header and SHA1 trailer are present. */
623 	if (pack->filesize < sizeof(hdr) + SHA1_DIGEST_LENGTH)
624 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
625 		    "short pack file");
626 
627 	if (pack->map) {
628 		memcpy(&hdr, pack->map, sizeof(hdr));
629 		mapoff += sizeof(hdr);
630 	} else {
631 		r = read(pack->fd, &hdr, sizeof(hdr));
632 		if (r == -1)
633 			return got_error_from_errno("read");
634 		if (r < sizeof(hdr))
635 			return got_error_msg(GOT_ERR_BAD_PACKFILE,
636 			    "short pack file");
637 	}
638 
639 	if (hdr.signature != htobe32(GOT_PACKFILE_SIGNATURE))
640 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
641 		    "bad packfile signature");
642 	if (hdr.version != htobe32(GOT_PACKFILE_VERSION))
643 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
644 		    "bad packfile version");
645 	nobj = be32toh(hdr.nobjects);
646 	if (nobj == 0)
647 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
648 		    "bad packfile with zero objects");
649 
650 	/* We compute the SHA1 of pack file contents and verify later on. */
651 	got_hash_init(&ctx, GOT_HASH_SHA1);
652 	got_hash_update(&ctx, &hdr, sizeof(hdr));
653 
654 	/*
655 	 * Create an in-memory pack index which will grow as objects
656 	 * IDs in the pack file are discovered. Only fields used to
657 	 * read deltified objects will be needed by the pack.c library
658 	 * code, so setting up just a pack index header is sufficient.
659 	 */
660 	memset(&packidx, 0, sizeof(packidx));
661 	packidx.hdr.magic = malloc(sizeof(uint32_t));
662 	if (packidx.hdr.magic == NULL)
663 		return got_error_from_errno("malloc");
664 	*packidx.hdr.magic = htobe32(GOT_PACKIDX_V2_MAGIC);
665 	packidx.hdr.version = malloc(sizeof(uint32_t));
666 	if (packidx.hdr.version == NULL) {
667 		err = got_error_from_errno("malloc");
668 		goto done;
669 	}
670 	*packidx.hdr.version = htobe32(GOT_PACKIDX_VERSION);
671 	packidx.hdr.fanout_table = calloc(GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS,
672 	    sizeof(uint32_t));
673 	if (packidx.hdr.fanout_table == NULL) {
674 		err = got_error_from_errno("calloc");
675 		goto done;
676 	}
677 	packidx.hdr.sorted_ids = calloc(nobj,
678 	    sizeof(struct got_packidx_object_id));
679 	if (packidx.hdr.sorted_ids == NULL) {
680 		err = got_error_from_errno("calloc");
681 		goto done;
682 	}
683 	packidx.hdr.crc32 = calloc(nobj, sizeof(uint32_t));
684 	if (packidx.hdr.crc32 == NULL) {
685 		err = got_error_from_errno("calloc");
686 		goto done;
687 	}
688 	packidx.hdr.offsets = calloc(nobj, sizeof(uint32_t));
689 	if (packidx.hdr.offsets == NULL) {
690 		err = got_error_from_errno("calloc");
691 		goto done;
692 	}
693 	/* Large offsets table is empty for pack files < 2 GB. */
694 	if (pack->filesize >= GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
695 		packidx.hdr.large_offsets = calloc(nobj, sizeof(uint64_t));
696 		if (packidx.hdr.large_offsets == NULL) {
697 			err = got_error_from_errno("calloc");
698 			goto done;
699 		}
700 	}
701 
702 	nvalid = 0;
703 	nloose = 0;
704 	objects = calloc(nobj, sizeof(struct got_indexed_object));
705 	if (objects == NULL)
706 		return got_error_from_errno("calloc");
707 
708 	/*
709 	 * First pass: locate all objects and identify un-deltified objects.
710 	 *
711 	 * When this pass has completed we will know offset, type, size, and
712 	 * CRC information for all objects in this pack file. We won't know
713 	 * any of the actual object IDs of deltified objects yet since we
714 	 * will not yet attempt to combine deltas.
715 	 */
716 	pass = 1;
717 	for (i = 0; i < nobj; i++) {
718 		/* Don't send too many progress privsep messages. */
719 		p_indexed = ((i + 1) * 100) / nobj;
720 		if (p_indexed != last_p_indexed) {
721 			err = report_progress(nobj, i + 1, nloose, 0,
722 			    rl, progress_cb, progress_arg);
723 			if (err)
724 				goto done;
725 			last_p_indexed = p_indexed;
726 		}
727 
728 		obj = &objects[i];
729 		obj->crc = crc32(0L, NULL, 0);
730 
731 		/* Store offset to type+size information for this object. */
732 		if (pack->map) {
733 			obj->off = mapoff;
734 		} else {
735 			obj->off = lseek(pack->fd, 0, SEEK_CUR);
736 			if (obj->off == -1) {
737 				err = got_error_from_errno("lseek");
738 				goto done;
739 			}
740 		}
741 
742 		err = read_packed_object(pack, obj, tmpfile, &ctx);
743 		if (err)
744 			goto done;
745 
746 		if (pack->map) {
747 			mapoff += obj->tslen + obj->len;
748 		} else {
749 			if (lseek(pack->fd, obj->off + obj->tslen + obj->len,
750 			    SEEK_SET) == -1) {
751 				err = got_error_from_errno("lseek");
752 				goto done;
753 			}
754 		}
755 
756 		if (obj->type == GOT_OBJ_TYPE_BLOB ||
757 		    obj->type == GOT_OBJ_TYPE_TREE ||
758 		    obj->type == GOT_OBJ_TYPE_COMMIT ||
759 		    obj->type == GOT_OBJ_TYPE_TAG) {
760 			obj->valid = 1;
761 			nloose++;
762 		} else {
763 			if (first_delta_idx == -1)
764 				first_delta_idx = i;
765 			if (obj->type == GOT_OBJ_TYPE_REF_DELTA)
766 				have_ref_deltas = 1;
767 		}
768 	}
769 	nvalid = nloose;
770 
771 	/*
772 	 * Having done a full pass over the pack file and can now
773 	 * verify its checksum.
774 	 */
775 	got_hash_final(&ctx, pack_sha1);
776 
777 	if (memcmp(pack_sha1_expected, pack_sha1, SHA1_DIGEST_LENGTH) != 0) {
778 		err = got_error(GOT_ERR_PACKFILE_CSUM);
779 		goto done;
780 	}
781 
782 	/* Verify the SHA1 checksum stored at the end of the pack file. */
783 	if (pack->map) {
784 		if (pack->filesize > SIZE_MAX) {
785 			err = got_error_fmt(GOT_ERR_RANGE,
786 			    "filesize %lld overflows size_t",
787 			    (long long)pack->filesize);
788 			goto done;
789 		}
790 
791 		memcpy(pack_sha1_expected, pack->map +
792 		    pack->filesize - SHA1_DIGEST_LENGTH,
793 		    SHA1_DIGEST_LENGTH);
794 	} else {
795 		ssize_t n;
796 		if (lseek(pack->fd, -SHA1_DIGEST_LENGTH, SEEK_END) == -1) {
797 			err = got_error_from_errno("lseek");
798 			goto done;
799 		}
800 		n = read(pack->fd, pack_sha1_expected, SHA1_DIGEST_LENGTH);
801 		if (n == -1) {
802 			err = got_error_from_errno("read");
803 			goto done;
804 		}
805 		if (n != SHA1_DIGEST_LENGTH) {
806 			err = got_error(GOT_ERR_IO);
807 			goto done;
808 		}
809 	}
810 	if (memcmp(pack_sha1, pack_sha1_expected, SHA1_DIGEST_LENGTH) != 0) {
811 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
812 		    "bad checksum in pack file trailer");
813 		goto done;
814 	}
815 
816 	if (first_delta_idx == -1)
817 		first_delta_idx = 0;
818 
819 	/* In order to resolve ref deltas we need an in-progress pack index. */
820 	if (have_ref_deltas)
821 		make_packidx(&packidx, nobj, objects);
822 
823 	/*
824 	 * Second pass: We can now resolve deltas to compute the IDs of
825 	 * objects which appear in deltified form. Because deltas can be
826 	 * chained this pass may require a couple of iterations until all
827 	 * IDs of deltified objects have been discovered.
828 	 */
829 	pass++;
830 	while (nvalid != nobj) {
831 		int n = 0;
832 		/*
833 		 * This loop will only run once unless the pack file
834 		 * contains ref deltas which refer to objects located
835 		 * later in the pack file, which is unusual.
836 		 * Offset deltas can always be resolved in one pass
837 		 * unless the packfile is corrupt.
838 		 */
839 		for (i = first_delta_idx; i < nobj; i++) {
840 			obj = &objects[i];
841 			if (obj->type != GOT_OBJ_TYPE_REF_DELTA &&
842 			    obj->type != GOT_OBJ_TYPE_OFFSET_DELTA)
843 				continue;
844 
845 			if (obj->valid)
846 				continue;
847 
848 			if (pack->map == NULL && lseek(pack->fd,
849 			    obj->off + obj->tslen, SEEK_SET) == -1) {
850 				err = got_error_from_errno("lseek");
851 				goto done;
852 			}
853 
854 			err = resolve_deltified_object(pack, &packidx, obj,
855 			    tmpfile, delta_base_file, delta_accum_file);
856 			if (err) {
857 				if (err->code != GOT_ERR_NO_OBJ)
858 					goto done;
859 				/*
860 				 * We cannot resolve this object yet because
861 				 * a delta base is unknown. Try again later.
862 				 */
863 				continue;
864 			}
865 
866 			obj->valid = 1;
867 			n++;
868 			if (have_ref_deltas)
869 				update_packidx(&packidx, nobj, obj);
870 			/* Don't send too many progress privsep messages. */
871 			p_resolved = ((nresolved + n) * 100) / nobj;
872 			if (p_resolved != last_p_resolved) {
873 				err = report_progress(nobj, nobj,
874 				    nloose, nresolved + n, rl,
875 				    progress_cb, progress_arg);
876 				if (err)
877 					goto done;
878 				last_p_resolved = p_resolved;
879 			}
880 
881 		}
882 		if (pass++ > 3 && n == 0) {
883 			err = got_error_msg(GOT_ERR_BAD_PACKFILE,
884 			    "could not resolve any of deltas; packfile could "
885 			    "be corrupt");
886 			goto done;
887 		}
888 		nresolved += n;
889 		nvalid += n;
890 	}
891 
892 	if (nloose + nresolved != nobj) {
893 		static char msg[64];
894 		snprintf(msg, sizeof(msg), "discovered only %d of %d objects",
895 		    nloose + nresolved, nobj);
896 		err = got_error_msg(GOT_ERR_BAD_PACKFILE, msg);
897 		goto done;
898 	}
899 
900 	err = report_progress(nobj, nobj, nloose, nresolved, NULL,
901 	    progress_cb, progress_arg);
902 	if (err)
903 		goto done;
904 
905 	make_packidx(&packidx, nobj, objects);
906 
907 	free(objects);
908 	objects = NULL;
909 
910 	got_hash_init(&ctx, GOT_HASH_SHA1);
911 	putbe32(buf, GOT_PACKIDX_V2_MAGIC);
912 	putbe32(buf + 4, GOT_PACKIDX_VERSION);
913 	err = got_pack_hwrite(idxfd, buf, 8, &ctx);
914 	if (err)
915 		goto done;
916 	err = got_pack_hwrite(idxfd, packidx.hdr.fanout_table,
917 	    GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS * sizeof(uint32_t), &ctx);
918 	if (err)
919 		goto done;
920 	err = got_pack_hwrite(idxfd, packidx.hdr.sorted_ids,
921 	    nobj * SHA1_DIGEST_LENGTH, &ctx);
922 	if (err)
923 		goto done;
924 	err = got_pack_hwrite(idxfd, packidx.hdr.crc32,
925 	    nobj * sizeof(uint32_t), &ctx);
926 	if (err)
927 		goto done;
928 	err = got_pack_hwrite(idxfd, packidx.hdr.offsets,
929 	    nobj * sizeof(uint32_t), &ctx);
930 	if (err)
931 		goto done;
932 	if (packidx.nlargeobj > 0) {
933 		err = got_pack_hwrite(idxfd, packidx.hdr.large_offsets,
934 		    packidx.nlargeobj * sizeof(uint64_t), &ctx);
935 		if (err)
936 			goto done;
937 	}
938 	err = got_pack_hwrite(idxfd, pack_sha1, SHA1_DIGEST_LENGTH, &ctx);
939 	if (err)
940 		goto done;
941 
942 	got_hash_final(&ctx, packidx_hash);
943 	w = write(idxfd, packidx_hash, sizeof(packidx_hash));
944 	if (w == -1) {
945 		err = got_error_from_errno("write");
946 		goto done;
947 	}
948 	if (w != sizeof(packidx_hash)) {
949 		err = got_error(GOT_ERR_IO);
950 		goto done;
951 	}
952 done:
953 	free(objects);
954 	free(packidx.hdr.magic);
955 	free(packidx.hdr.version);
956 	free(packidx.hdr.fanout_table);
957 	free(packidx.hdr.sorted_ids);
958 	free(packidx.hdr.offsets);
959 	free(packidx.hdr.large_offsets);
960 	return err;
961 }