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 <sys/queue.h>
19 #include <sys/stat.h>
20 #include <sys/time.h>
21 #include <sys/types.h>
22 #include <sys/uio.h>
23 #include <sys/mman.h>
24 
25 #include <stdint.h>
26 #include <errno.h>
27 #include <imsg.h>
28 #include <limits.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <ctype.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36 #include <zlib.h>
37 #include <err.h>
38 #include <assert.h>
39 #include <dirent.h>
40 
41 #include "got_error.h"
42 #include "got_object.h"
43 
44 #include "got_lib_sha1.h"
45 #include "got_lib_delta.h"
46 #include "got_lib_inflate.h"
47 #include "got_lib_object.h"
48 #include "got_lib_object_parse.h"
49 #include "got_lib_object_idset.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_pack.h"
52 #include "got_lib_ratelimit.h"
53 #include "got_lib_pack_index.h"
54 #include "got_lib_delta_cache.h"
55 
56 struct got_indexed_object {
57 	struct got_object_id id;
58 
59 	/*
60 	 * Has this object been fully resolved?
61 	 * If so, we know its ID, otherwise we don't and 'id' is invalid.
62 	 */
63 	int valid;
64 
65 	/* Offset of type+size field for this object in pack file. */
66 	off_t off;
67 
68 	/* Type+size values parsed from pack file. */
69 	uint8_t type;
70 	uint64_t size;
71 
72 	/* Length of on-disk type+size data. */
73 	size_t tslen;
74 
75 	/* Length of object data following type+size. */
76 	size_t len;
77 
78 	uint32_t crc;
79 
80 	union {
81 		struct {
82 			/* For ref deltas. */
83 			struct got_object_id ref_id;
84 		} ref;
85 		struct {
86 			/* For offset deltas. */
87 			off_t base_offset;
88 			size_t base_offsetlen;
89 		} ofs;
90 	} delta;
91 };
92 
93 static void
94 putbe32(char *b, uint32_t n)
95 {
96 	b[0] = n >> 24;
97 	b[1] = n >> 16;
98 	b[2] = n >> 8;
99 	b[3] = n >> 0;
100 }
101 
102 static const struct got_error *
103 get_obj_type_label(const char **label, int obj_type)
104 {
105 	const struct got_error *err = NULL;
106 
107 	switch (obj_type) {
108 	case GOT_OBJ_TYPE_BLOB:
109 		*label = GOT_OBJ_LABEL_BLOB;
110 		break;
111 	case GOT_OBJ_TYPE_TREE:
112 		*label = GOT_OBJ_LABEL_TREE;
113 		break;
114 	case GOT_OBJ_TYPE_COMMIT:
115 		*label = GOT_OBJ_LABEL_COMMIT;
116 		break;
117 	case GOT_OBJ_TYPE_TAG:
118 		*label = GOT_OBJ_LABEL_TAG;
119 		break;
120 	default:
121 		*label = NULL;
122 		err = got_error(GOT_ERR_OBJ_TYPE);
123 		break;
124 	}
125 
126 	return err;
127 }
128 
129 static const struct got_error *
130 read_checksum(uint32_t *crc, SHA1_CTX *sha1_ctx, int fd, size_t len)
131 {
132 	uint8_t buf[8192];
133 	size_t n;
134 	ssize_t r;
135 
136 	for (n = len; n > 0; n -= r){
137 		r = read(fd, buf, n > sizeof(buf) ? sizeof(buf) : n);
138 		if (r == -1)
139 			return got_error_from_errno("read");
140 		if (r == 0)
141 			break;
142 		if (crc)
143 			*crc = crc32(*crc, buf, r);
144 		if (sha1_ctx)
145 			SHA1Update(sha1_ctx, buf, r);
146 	}
147 
148 	return NULL;
149 }
150 
151 static const struct got_error *
152 read_file_sha1(SHA1_CTX *ctx, FILE *f, size_t len)
153 {
154 	uint8_t buf[8192];
155 	size_t n, r;
156 
157 	for (n = len; n > 0; n -= r) {
158 		r = fread(buf, 1, n > sizeof(buf) ? sizeof(buf) : n, f);
159 		if (r == 0) {
160 			if (feof(f))
161 				return NULL;
162 			return got_ferror(f, GOT_ERR_IO);
163 		}
164 		SHA1Update(ctx, buf, r);
165 	}
166 
167 	return NULL;
168 }
169 
170 static const struct got_error *
171 read_packed_object(struct got_pack *pack, struct got_indexed_object *obj,
172     FILE *tmpfile, SHA1_CTX *pack_sha1_ctx)
173 {
174 	const struct got_error *err = NULL;
175 	SHA1_CTX ctx;
176 	uint8_t *data = NULL;
177 	size_t datalen = 0;
178 	ssize_t n;
179 	char *header;
180 	size_t headerlen;
181 	const char *obj_label;
182 	size_t mapoff = obj->off;
183 	struct got_inflate_checksum csum;
184 
185 	memset(&csum, 0, sizeof(csum));
186 	csum.input_sha1 = pack_sha1_ctx;
187 	csum.input_crc = &obj->crc;
188 
189 	err = got_pack_parse_object_type_and_size(&obj->type, &obj->size,
190 	    &obj->tslen, pack, obj->off);
191 	if (err)
192 		return err;
193 
194 	if (pack->map) {
195 		obj->crc = crc32(obj->crc, pack->map + mapoff, obj->tslen);
196 		SHA1Update(pack_sha1_ctx, pack->map + mapoff, obj->tslen);
197 		mapoff += obj->tslen;
198 	} else {
199 		/* XXX Seek back and get the CRC of on-disk type+size bytes. */
200 		if (lseek(pack->fd, obj->off, SEEK_SET) == -1)
201 			return got_error_from_errno("lseek");
202 		err = read_checksum(&obj->crc, pack_sha1_ctx,
203 		    pack->fd, obj->tslen);
204 		if (err)
205 			return err;
206 	}
207 
208 	switch (obj->type) {
209 	case GOT_OBJ_TYPE_BLOB:
210 	case GOT_OBJ_TYPE_COMMIT:
211 	case GOT_OBJ_TYPE_TREE:
212 	case GOT_OBJ_TYPE_TAG:
213 		if (obj->size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
214 			if (fseek(tmpfile, 0L, SEEK_SET) == -1) {
215 				err = got_error_from_errno("fseek");
216 				break;
217 			}
218 			if (pack->map) {
219 				err = got_inflate_to_file_mmap(&datalen,
220 				    &obj->len, &csum, pack->map, mapoff,
221 				    pack->filesize - mapoff, tmpfile);
222 			} else {
223 				err = got_inflate_to_file_fd(&datalen,
224 				    &obj->len, &csum, pack->fd, tmpfile);
225 			}
226 		} else {
227 			if (pack->map) {
228 				err = got_inflate_to_mem_mmap(&data, &datalen,
229 				    &obj->len, &csum, pack->map, mapoff,
230 				    pack->filesize - mapoff);
231 			} else {
232 				err = got_inflate_to_mem_fd(&data, &datalen,
233 				    &obj->len, &csum, obj->size, pack->fd);
234 			}
235 		}
236 		if (err)
237 			break;
238 		SHA1Init(&ctx);
239 		err = get_obj_type_label(&obj_label, obj->type);
240 		if (err) {
241 			free(data);
242 			break;
243 		}
244 		if (asprintf(&header, "%s %lld", obj_label,
245 		    (long long)obj->size) == -1) {
246 			err = got_error_from_errno("asprintf");
247 			free(data);
248 			break;
249 		}
250 		headerlen = strlen(header) + 1;
251 		SHA1Update(&ctx, header, headerlen);
252 		if (obj->size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
253 			err = read_file_sha1(&ctx, tmpfile, datalen);
254 			if (err) {
255 				free(header);
256 				free(data);
257 				break;
258 			}
259 		} else
260 			SHA1Update(&ctx, data, datalen);
261 		SHA1Final(obj->id.sha1, &ctx);
262 		free(header);
263 		free(data);
264 		break;
265 	case GOT_OBJ_TYPE_REF_DELTA:
266 		memset(obj->id.sha1, 0xff, SHA1_DIGEST_LENGTH);
267 		if (pack->map) {
268 			if (mapoff + SHA1_DIGEST_LENGTH >= pack->filesize) {
269 				err = got_error(GOT_ERR_BAD_PACKFILE);
270 				break;
271 			}
272 			if (mapoff + SHA1_DIGEST_LENGTH > SIZE_MAX) {
273 				err = got_error_fmt(GOT_ERR_RANGE,
274 				    "mapoff %lld would overflow size_t",
275 				    (long long)mapoff + SHA1_DIGEST_LENGTH);
276 				break;
277 			}
278 			memcpy(obj->delta.ref.ref_id.sha1, pack->map + mapoff,
279 			    SHA1_DIGEST_LENGTH);
280 			obj->crc = crc32(obj->crc, pack->map + mapoff,
281 			    SHA1_DIGEST_LENGTH);
282 			SHA1Update(pack_sha1_ctx, pack->map + mapoff,
283 			    SHA1_DIGEST_LENGTH);
284 			mapoff += SHA1_DIGEST_LENGTH;
285 			err = got_inflate_to_mem_mmap(NULL, &datalen,
286 			    &obj->len, &csum, pack->map, mapoff,
287 			    pack->filesize - mapoff);
288 			if (err)
289 				break;
290 		} else {
291 			n = read(pack->fd, obj->delta.ref.ref_id.sha1,
292 			    SHA1_DIGEST_LENGTH);
293 			if (n == -1) {
294 				err = got_error_from_errno("read");
295 				break;
296 			}
297 			if (n < sizeof(obj->id)) {
298 				err = got_error(GOT_ERR_BAD_PACKFILE);
299 				break;
300 			}
301 			obj->crc = crc32(obj->crc, obj->delta.ref.ref_id.sha1,
302 			    SHA1_DIGEST_LENGTH);
303 			SHA1Update(pack_sha1_ctx, obj->delta.ref.ref_id.sha1,
304 			    SHA1_DIGEST_LENGTH);
305 			err = got_inflate_to_mem_fd(NULL, &datalen, &obj->len,
306 			    &csum, obj->size, pack->fd);
307 			if (err)
308 				break;
309 		}
310 		obj->len += SHA1_DIGEST_LENGTH;
311 		break;
312 	case GOT_OBJ_TYPE_OFFSET_DELTA:
313 		memset(obj->id.sha1, 0xff, SHA1_DIGEST_LENGTH);
314 		err = got_pack_parse_offset_delta(&obj->delta.ofs.base_offset,
315 		    &obj->delta.ofs.base_offsetlen, pack, obj->off,
316 		    obj->tslen);
317 		if (err)
318 			break;
319 
320 		if (pack->map) {
321 			if (mapoff + obj->delta.ofs.base_offsetlen >=
322 			    pack->filesize) {
323 				err = got_error(GOT_ERR_BAD_PACKFILE);
324 				break;
325 			}
326 
327 			if (mapoff + obj->delta.ofs.base_offsetlen >
328 			    SIZE_MAX) {
329 				err = got_error_fmt(GOT_ERR_RANGE,
330 				    "mapoff %lld would overflow size_t",
331 				    (long long)mapoff
332 				    + obj->delta.ofs.base_offsetlen);
333 			}
334 
335 			obj->crc = crc32(obj->crc, pack->map + mapoff,
336 			    obj->delta.ofs.base_offsetlen);
337 			SHA1Update(pack_sha1_ctx, pack->map + mapoff,
338 			    obj->delta.ofs.base_offsetlen);
339 			mapoff += obj->delta.ofs.base_offsetlen;
340 			err = got_inflate_to_mem_mmap(NULL, &datalen,
341 			    &obj->len, &csum, pack->map, mapoff,
342 			    pack->filesize - mapoff);
343 			if (err)
344 				break;
345 		} else {
346 			/*
347 			 * XXX Seek back and get CRC and SHA1 of on-disk
348 			 * offset bytes.
349 			 */
350 			if (lseek(pack->fd, obj->off + obj->tslen, SEEK_SET)
351 			    == -1) {
352 				err = got_error_from_errno("lseek");
353 				break;
354 			}
355 			err = read_checksum(&obj->crc, pack_sha1_ctx,
356 			    pack->fd, obj->delta.ofs.base_offsetlen);
357 			if (err)
358 				break;
359 
360 			err = got_inflate_to_mem_fd(NULL, &datalen, &obj->len,
361 			    &csum, obj->size, pack->fd);
362 			if (err)
363 				break;
364 		}
365 		obj->len += obj->delta.ofs.base_offsetlen;
366 		break;
367 	default:
368 		err = got_error(GOT_ERR_OBJ_TYPE);
369 		break;
370 	}
371 
372 	return err;
373 }
374 
375 const struct got_error *
376 got_pack_hwrite(int fd, void *buf, int len, SHA1_CTX *ctx)
377 {
378 	ssize_t w;
379 
380 	SHA1Update(ctx, buf, len);
381 
382 	w = write(fd, buf, len);
383 	if (w == -1)
384 		return got_error_from_errno("write");
385 	if (w != len)
386 		return got_error(GOT_ERR_IO);
387 
388 	return NULL;
389 }
390 
391 static const struct got_error *
392 resolve_deltified_object(struct got_pack *pack, struct got_packidx *packidx,
393     struct got_indexed_object *obj, FILE *tmpfile, FILE *delta_base_file,
394     FILE *delta_accum_file)
395 {
396 	const struct got_error *err = NULL;
397 	struct got_delta_chain deltas;
398 	struct got_delta *delta;
399 	uint8_t *buf = NULL;
400 	size_t len = 0;
401 	SHA1_CTX ctx;
402 	char *header = NULL;
403 	size_t headerlen;
404 	uint64_t max_size;
405 	int base_obj_type;
406 	const char *obj_label;
407 
408 	deltas.nentries = 0;
409 	STAILQ_INIT(&deltas.entries);
410 
411 	err = got_pack_resolve_delta_chain(&deltas, packidx, pack,
412 	    obj->off, obj->tslen, obj->type, obj->size,
413 	    GOT_DELTA_CHAIN_RECURSION_MAX);
414 	if (err)
415 		goto done;
416 
417 	err = got_pack_get_delta_chain_max_size(&max_size, &deltas, pack);
418 	if (err)
419 		goto done;
420 	if (max_size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
421 		rewind(tmpfile);
422 		rewind(delta_base_file);
423 		rewind(delta_accum_file);
424 		err = got_pack_dump_delta_chain_to_file(&len, &deltas,
425 		    pack, tmpfile, delta_base_file, delta_accum_file);
426 		if (err)
427 			goto done;
428 	} else {
429 		err = got_pack_dump_delta_chain_to_mem(&buf, &len,
430 		    &deltas, pack);
431 	}
432 	if (err)
433 		goto done;
434 
435 	err = got_delta_chain_get_base_type(&base_obj_type, &deltas);
436 	if (err)
437 		goto done;
438 	err = get_obj_type_label(&obj_label, base_obj_type);
439 	if (err)
440 		goto done;
441 	if (asprintf(&header, "%s %zd", obj_label, len) == -1) {
442 		err = got_error_from_errno("asprintf");
443 		goto done;
444 	}
445 	headerlen = strlen(header) + 1;
446 	SHA1Init(&ctx);
447 	SHA1Update(&ctx, header, headerlen);
448 	if (max_size > GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
449 		err = read_file_sha1(&ctx, tmpfile, len);
450 		if (err)
451 			goto done;
452 	} else
453 		SHA1Update(&ctx, buf, len);
454 	SHA1Final(obj->id.sha1, &ctx);
455 done:
456 	free(buf);
457 	free(header);
458 	while (!STAILQ_EMPTY(&deltas.entries)) {
459 		delta = STAILQ_FIRST(&deltas.entries);
460 		STAILQ_REMOVE_HEAD(&deltas.entries, entry);
461 		free(delta);
462 	}
463 	return err;
464 }
465 
466 /* Determine the slot in the pack index a given object ID should use. */
467 static int
468 find_object_idx(struct got_packidx *packidx, uint8_t *sha1)
469 {
470 	u_int8_t id0 = sha1[0];
471 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
472 	int left = 0, right = nindexed - 1;
473 	int cmp = 0, i = 0;
474 
475 	if (id0 > 0)
476 		left = be32toh(packidx->hdr.fanout_table[id0 - 1]);
477 
478 	while (left <= right) {
479 		struct got_packidx_object_id *oid;
480 
481 		i = ((left + right) / 2);
482 		oid = &packidx->hdr.sorted_ids[i];
483 
484 		cmp = memcmp(sha1, oid->sha1, SHA1_DIGEST_LENGTH);
485 		if (cmp == 0)
486 			return -1; /* object already indexed */
487 		else if (cmp > 0)
488 			left = i + 1;
489 		else if (cmp < 0)
490 			right = i - 1;
491 	}
492 
493 	return left;
494 }
495 
496 #if 0
497 static void
498 print_packidx(struct got_packidx *packidx)
499 {
500 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
501 	int i;
502 
503 	fprintf(stderr, "object IDs:\n");
504 	for (i = 0; i < nindexed; i++) {
505 		char hex[SHA1_DIGEST_STRING_LENGTH];
506 		got_sha1_digest_to_str(packidx->hdr.sorted_ids[i].sha1,
507 		    hex, sizeof(hex));
508 		fprintf(stderr, "%s\n", hex);
509 	}
510 	fprintf(stderr, "\n");
511 
512 	fprintf(stderr, "object offsets:\n");
513 	for (i = 0; i < nindexed; i++) {
514 		uint32_t offset = be32toh(packidx->hdr.offsets[i]);
515 		if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
516 			int j = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
517 			fprintf(stderr, "%u -> %llu\n", offset,
518 			    be64toh(packidx->hdr.large_offsets[j]));
519 		} else
520 			fprintf(stderr, "%u\n", offset);
521 	}
522 	fprintf(stderr, "\n");
523 
524 	fprintf(stderr, "fanout table:");
525 	for (i = 0; i <= 0xff; i++)
526 		fprintf(stderr, " %u", be32toh(packidx->hdr.fanout_table[i]));
527 	fprintf(stderr, "\n");
528 }
529 #endif
530 
531 static void
532 add_indexed_object(struct got_packidx *packidx, uint32_t idx,
533     struct got_indexed_object *obj)
534 {
535 	int i;
536 
537 	memcpy(packidx->hdr.sorted_ids[idx].sha1, obj->id.sha1,
538 	    SHA1_DIGEST_LENGTH);
539 	packidx->hdr.crc32[idx] = htobe32(obj->crc);
540 	if (obj->off < GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX)
541 		packidx->hdr.offsets[idx] = htobe32(obj->off);
542 	else {
543 		packidx->hdr.offsets[idx] = htobe32(packidx->nlargeobj |
544 		    GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX);
545 		packidx->hdr.large_offsets[packidx->nlargeobj] =
546 		    htobe64(obj->off);
547 		packidx->nlargeobj++;
548 	}
549 
550 	for (i = obj->id.sha1[0]; i <= 0xff; i++) {
551 		uint32_t n = be32toh(packidx->hdr.fanout_table[i]);
552 		packidx->hdr.fanout_table[i] = htobe32(n + 1);
553 	}
554 }
555 
556 static int
557 indexed_obj_cmp(const void *pa, const void *pb)
558 {
559 	struct got_indexed_object *a, *b;
560 
561 	a = (struct got_indexed_object *)pa;
562 	b = (struct got_indexed_object *)pb;
563 	return got_object_id_cmp(&a->id, &b->id);
564 }
565 
566 static void
567 make_packidx(struct got_packidx *packidx, uint32_t nobj,
568     struct got_indexed_object *objects)
569 {
570 	struct got_indexed_object *obj;
571 	int i;
572 	uint32_t idx = 0;
573 
574 	qsort(objects, nobj, sizeof(struct got_indexed_object),
575 	    indexed_obj_cmp);
576 
577 	memset(packidx->hdr.fanout_table, 0,
578 	    GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS * sizeof(uint32_t));
579 	packidx->nlargeobj = 0;
580 
581 	for (i = 0; i < nobj; i++) {
582 		obj = &objects[i];
583 		if (obj->valid)
584 			add_indexed_object(packidx, idx++, obj);
585 	}
586 }
587 
588 static void
589 update_packidx(struct got_packidx *packidx, uint32_t nobj,
590     struct got_indexed_object *obj)
591 {
592 	int idx;
593 	uint32_t nindexed = be32toh(packidx->hdr.fanout_table[0xff]);
594 
595 	idx = find_object_idx(packidx, obj->id.sha1);
596 	if (idx == -1) {
597 		char hex[SHA1_DIGEST_STRING_LENGTH];
598 		got_sha1_digest_to_str(obj->id.sha1, hex, sizeof(hex));
599 		return; /* object already indexed */
600 	}
601 
602 	memmove(&packidx->hdr.sorted_ids[idx + 1],
603 	    &packidx->hdr.sorted_ids[idx],
604 	    sizeof(struct got_packidx_object_id) * (nindexed - idx));
605 	memmove(&packidx->hdr.offsets[idx + 1], &packidx->hdr.offsets[idx],
606 	    sizeof(uint32_t) * (nindexed - idx));
607 
608 	add_indexed_object(packidx, idx, obj);
609 }
610 
611 static const struct got_error *
612 report_progress(uint32_t nobj_total, uint32_t nobj_indexed, uint32_t nobj_loose,
613     uint32_t nobj_resolved, struct got_ratelimit *rl,
614     got_pack_index_progress_cb progress_cb, void *progress_arg)
615 {
616 	const struct got_error *err;
617 	int elapsed = 0;
618 
619 	if (rl) {
620 		err = got_ratelimit_check(&elapsed, rl);
621 		if (err || !elapsed)
622 			return err;
623 	}
624 
625 	return progress_cb(progress_arg, nobj_total, nobj_indexed, nobj_loose,
626 	    nobj_resolved);
627 }
628 
629 const struct got_error *
630 got_pack_index(struct got_pack *pack, int idxfd, FILE *tmpfile,
631     FILE *delta_base_file, FILE *delta_accum_file, uint8_t *pack_sha1_expected,
632     got_pack_index_progress_cb progress_cb, void *progress_arg,
633     struct got_ratelimit *rl)
634 {
635 	const struct got_error *err;
636 	struct got_packfile_hdr hdr;
637 	struct got_packidx packidx;
638 	char buf[8];
639 	char pack_sha1[SHA1_DIGEST_LENGTH];
640 	uint32_t nobj, nvalid, nloose, nresolved = 0, i;
641 	struct got_indexed_object *objects = NULL, *obj;
642 	SHA1_CTX ctx;
643 	uint8_t packidx_hash[SHA1_DIGEST_LENGTH];
644 	ssize_t r, w;
645 	int pass, have_ref_deltas = 0, first_delta_idx = -1;
646 	size_t mapoff = 0;
647 	int p_indexed = 0, last_p_indexed = -1;
648 	int p_resolved = 0, last_p_resolved = -1;
649 
650 	/* Require that pack file header and SHA1 trailer are present. */
651 	if (pack->filesize < sizeof(hdr) + SHA1_DIGEST_LENGTH)
652 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
653 		    "short pack file");
654 
655 	if (pack->map) {
656 		memcpy(&hdr, pack->map, sizeof(hdr));
657 		mapoff += sizeof(hdr);
658 	} else {
659 		r = read(pack->fd, &hdr, sizeof(hdr));
660 		if (r == -1)
661 			return got_error_from_errno("read");
662 		if (r < sizeof(hdr))
663 			return got_error_msg(GOT_ERR_BAD_PACKFILE,
664 			    "short pack file");
665 	}
666 
667 	if (hdr.signature != htobe32(GOT_PACKFILE_SIGNATURE))
668 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
669 		    "bad packfile signature");
670 	if (hdr.version != htobe32(GOT_PACKFILE_VERSION))
671 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
672 		    "bad packfile version");
673 	nobj = be32toh(hdr.nobjects);
674 	if (nobj == 0)
675 		return got_error_msg(GOT_ERR_BAD_PACKFILE,
676 		    "bad packfile with zero objects");
677 
678 	/* We compute the SHA1 of pack file contents and verify later on. */
679 	SHA1Init(&ctx);
680 	SHA1Update(&ctx, (void *)&hdr, sizeof(hdr));
681 
682 	/*
683 	 * Create an in-memory pack index which will grow as objects
684 	 * IDs in the pack file are discovered. Only fields used to
685 	 * read deltified objects will be needed by the pack.c library
686 	 * code, so setting up just a pack index header is sufficient.
687 	 */
688 	memset(&packidx, 0, sizeof(packidx));
689 	packidx.hdr.magic = malloc(sizeof(uint32_t));
690 	if (packidx.hdr.magic == NULL)
691 		return got_error_from_errno("malloc");
692 	*packidx.hdr.magic = htobe32(GOT_PACKIDX_V2_MAGIC);
693 	packidx.hdr.version = malloc(sizeof(uint32_t));
694 	if (packidx.hdr.version == NULL) {
695 		err = got_error_from_errno("malloc");
696 		goto done;
697 	}
698 	*packidx.hdr.version = htobe32(GOT_PACKIDX_VERSION);
699 	packidx.hdr.fanout_table = calloc(GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS,
700 	    sizeof(uint32_t));
701 	if (packidx.hdr.fanout_table == NULL) {
702 		err = got_error_from_errno("calloc");
703 		goto done;
704 	}
705 	packidx.hdr.sorted_ids = calloc(nobj,
706 	    sizeof(struct got_packidx_object_id));
707 	if (packidx.hdr.sorted_ids == NULL) {
708 		err = got_error_from_errno("calloc");
709 		goto done;
710 	}
711 	packidx.hdr.crc32 = calloc(nobj, sizeof(uint32_t));
712 	if (packidx.hdr.crc32 == NULL) {
713 		err = got_error_from_errno("calloc");
714 		goto done;
715 	}
716 	packidx.hdr.offsets = calloc(nobj, sizeof(uint32_t));
717 	if (packidx.hdr.offsets == NULL) {
718 		err = got_error_from_errno("calloc");
719 		goto done;
720 	}
721 	/* Large offsets table is empty for pack files < 2 GB. */
722 	if (pack->filesize >= GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
723 		packidx.hdr.large_offsets = calloc(nobj, sizeof(uint64_t));
724 		if (packidx.hdr.large_offsets == NULL) {
725 			err = got_error_from_errno("calloc");
726 			goto done;
727 		}
728 	}
729 
730 	nvalid = 0;
731 	nloose = 0;
732 	objects = calloc(nobj, sizeof(struct got_indexed_object));
733 	if (objects == NULL)
734 		return got_error_from_errno("calloc");
735 
736 	/*
737 	 * First pass: locate all objects and identify un-deltified objects.
738 	 *
739 	 * When this pass has completed we will know offset, type, size, and
740 	 * CRC information for all objects in this pack file. We won't know
741 	 * any of the actual object IDs of deltified objects yet since we
742 	 * will not yet attempt to combine deltas.
743 	 */
744 	pass = 1;
745 	for (i = 0; i < nobj; i++) {
746 		/* Don't send too many progress privsep messages. */
747 		p_indexed = ((i + 1) * 100) / nobj;
748 		if (p_indexed != last_p_indexed) {
749 			err = report_progress(nobj, i + 1, nloose, 0,
750 			    rl, progress_cb, progress_arg);
751 			if (err)
752 				goto done;
753 			last_p_indexed = p_indexed;
754 		}
755 
756 		obj = &objects[i];
757 		obj->crc = crc32(0L, NULL, 0);
758 
759 		/* Store offset to type+size information for this object. */
760 		if (pack->map) {
761 			obj->off = mapoff;
762 		} else {
763 			obj->off = lseek(pack->fd, 0, SEEK_CUR);
764 			if (obj->off == -1) {
765 				err = got_error_from_errno("lseek");
766 				goto done;
767 			}
768 		}
769 
770 		err = read_packed_object(pack, obj, tmpfile, &ctx);
771 		if (err)
772 			goto done;
773 
774 		if (pack->map) {
775 			mapoff += obj->tslen + obj->len;
776 		} else {
777 			if (lseek(pack->fd, obj->off + obj->tslen + obj->len,
778 			    SEEK_SET) == -1) {
779 				err = got_error_from_errno("lseek");
780 				goto done;
781 			}
782 		}
783 
784 		if (obj->type == GOT_OBJ_TYPE_BLOB ||
785 		    obj->type == GOT_OBJ_TYPE_TREE ||
786 		    obj->type == GOT_OBJ_TYPE_COMMIT ||
787 		    obj->type == GOT_OBJ_TYPE_TAG) {
788 			obj->valid = 1;
789 			nloose++;
790 		} else {
791 			if (first_delta_idx == -1)
792 				first_delta_idx = i;
793 			if (obj->type == GOT_OBJ_TYPE_REF_DELTA)
794 				have_ref_deltas = 1;
795 		}
796 	}
797 	nvalid = nloose;
798 
799 	/*
800 	 * Having done a full pass over the pack file and can now
801 	 * verify its checksum.
802 	 */
803 	SHA1Final(pack_sha1, &ctx);
804 
805 	if (memcmp(pack_sha1_expected, pack_sha1, SHA1_DIGEST_LENGTH) != 0) {
806 		err = got_error(GOT_ERR_PACKFILE_CSUM);
807 		goto done;
808 	}
809 
810 	/* Verify the SHA1 checksum stored at the end of the pack file. */
811 	if (pack->map) {
812 		if (pack->filesize > SIZE_MAX) {
813 			err = got_error_fmt(GOT_ERR_RANGE,
814 			    "filesize %lld overflows size_t",
815 			    (long long)pack->filesize);
816 			goto done;
817 		}
818 
819 		memcpy(pack_sha1_expected, pack->map +
820 		    pack->filesize - SHA1_DIGEST_LENGTH,
821 		    SHA1_DIGEST_LENGTH);
822 	} else {
823 		ssize_t n;
824 		if (lseek(pack->fd, -SHA1_DIGEST_LENGTH, SEEK_END) == -1) {
825 			err = got_error_from_errno("lseek");
826 			goto done;
827 		}
828 		n = read(pack->fd, pack_sha1_expected, SHA1_DIGEST_LENGTH);
829 		if (n == -1) {
830 			err = got_error_from_errno("read");
831 			goto done;
832 		}
833 		if (n != SHA1_DIGEST_LENGTH) {
834 			err = got_error(GOT_ERR_IO);
835 			goto done;
836 		}
837 	}
838 	if (memcmp(pack_sha1, pack_sha1_expected, SHA1_DIGEST_LENGTH) != 0) {
839 		err = got_error_msg(GOT_ERR_BAD_PACKFILE,
840 		    "bad checksum in pack file trailer");
841 		goto done;
842 	}
843 
844 	if (first_delta_idx == -1)
845 		first_delta_idx = 0;
846 
847 	/* In order to resolve ref deltas we need an in-progress pack index. */
848 	if (have_ref_deltas)
849 		make_packidx(&packidx, nobj, objects);
850 
851 	/*
852 	 * Second pass: We can now resolve deltas to compute the IDs of
853 	 * objects which appear in deltified form. Because deltas can be
854 	 * chained this pass may require a couple of iterations until all
855 	 * IDs of deltified objects have been discovered.
856 	 */
857 	pass++;
858 	while (nvalid != nobj) {
859 		int n = 0;
860 		/*
861 		 * This loop will only run once unless the pack file
862 		 * contains ref deltas which refer to objects located
863 		 * later in the pack file, which is unusual.
864 		 * Offset deltas can always be resolved in one pass
865 		 * unless the packfile is corrupt.
866 		 */
867 		for (i = first_delta_idx; i < nobj; i++) {
868 			obj = &objects[i];
869 			if (obj->type != GOT_OBJ_TYPE_REF_DELTA &&
870 			    obj->type != GOT_OBJ_TYPE_OFFSET_DELTA)
871 				continue;
872 
873 			if (obj->valid)
874 				continue;
875 
876 			if (pack->map == NULL && lseek(pack->fd,
877 			    obj->off + obj->tslen, SEEK_SET) == -1) {
878 				err = got_error_from_errno("lseek");
879 				goto done;
880 			}
881 
882 			err = resolve_deltified_object(pack, &packidx, obj,
883 			    tmpfile, delta_base_file, delta_accum_file);
884 			if (err) {
885 				if (err->code != GOT_ERR_NO_OBJ)
886 					goto done;
887 				/*
888 				 * We cannot resolve this object yet because
889 				 * a delta base is unknown. Try again later.
890 				 */
891 				continue;
892 			}
893 
894 			obj->valid = 1;
895 			n++;
896 			if (have_ref_deltas)
897 				update_packidx(&packidx, nobj, obj);
898 			/* Don't send too many progress privsep messages. */
899 			p_resolved = ((nresolved + n) * 100) / nobj;
900 			if (p_resolved != last_p_resolved) {
901 				err = report_progress(nobj, nobj,
902 				    nloose, nresolved + n, rl,
903 				    progress_cb, progress_arg);
904 				if (err)
905 					goto done;
906 				last_p_resolved = p_resolved;
907 			}
908 
909 		}
910 		if (pass++ > 3 && n == 0) {
911 			err = got_error_msg(GOT_ERR_BAD_PACKFILE,
912 			    "could not resolve any of deltas; packfile could "
913 			    "be corrupt");
914 			goto done;
915 		}
916 		nresolved += n;
917 		nvalid += nresolved;
918 	}
919 
920 	if (nloose + nresolved != nobj) {
921 		static char msg[64];
922 		snprintf(msg, sizeof(msg), "discovered only %d of %d objects",
923 		    nloose + nresolved, nobj);
924 		err = got_error_msg(GOT_ERR_BAD_PACKFILE, msg);
925 		goto done;
926 	}
927 
928 	err = report_progress(nobj, nobj, nloose, nresolved, NULL,
929 	    progress_cb, progress_arg);
930 	if (err)
931 		goto done;
932 
933 	make_packidx(&packidx, nobj, objects);
934 
935 	free(objects);
936 	objects = NULL;
937 
938 	SHA1Init(&ctx);
939 	putbe32(buf, GOT_PACKIDX_V2_MAGIC);
940 	putbe32(buf + 4, GOT_PACKIDX_VERSION);
941 	err = got_pack_hwrite(idxfd, buf, 8, &ctx);
942 	if (err)
943 		goto done;
944 	err = got_pack_hwrite(idxfd, packidx.hdr.fanout_table,
945 	    GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS * sizeof(uint32_t), &ctx);
946 	if (err)
947 		goto done;
948 	err = got_pack_hwrite(idxfd, packidx.hdr.sorted_ids,
949 	    nobj * SHA1_DIGEST_LENGTH, &ctx);
950 	if (err)
951 		goto done;
952 	err = got_pack_hwrite(idxfd, packidx.hdr.crc32,
953 	    nobj * sizeof(uint32_t), &ctx);
954 	if (err)
955 		goto done;
956 	err = got_pack_hwrite(idxfd, packidx.hdr.offsets,
957 	    nobj * sizeof(uint32_t), &ctx);
958 	if (err)
959 		goto done;
960 	if (packidx.nlargeobj > 0) {
961 		err = got_pack_hwrite(idxfd, packidx.hdr.large_offsets,
962 		    packidx.nlargeobj * sizeof(uint64_t), &ctx);
963 		if (err)
964 			goto done;
965 	}
966 	err = got_pack_hwrite(idxfd, pack_sha1, SHA1_DIGEST_LENGTH, &ctx);
967 	if (err)
968 		goto done;
969 
970 	SHA1Final(packidx_hash, &ctx);
971 	w = write(idxfd, packidx_hash, sizeof(packidx_hash));
972 	if (w == -1) {
973 		err = got_error_from_errno("write");
974 		goto done;
975 	}
976 	if (w != sizeof(packidx_hash)) {
977 		err = got_error(GOT_ERR_IO);
978 		goto done;
979 	}
980 done:
981 	free(objects);
982 	free(packidx.hdr.magic);
983 	free(packidx.hdr.version);
984 	free(packidx.hdr.fanout_table);
985 	free(packidx.hdr.sorted_ids);
986 	free(packidx.hdr.offsets);
987 	free(packidx.hdr.large_offsets);
988 	return err;
989 }