multi-pack-index: verify bad header
[git/git.git] / midx.c
CommitLineData
a3407730 1#include "cache.h"
c4d25228 2#include "config.h"
fc59e748 3#include "csum-file.h"
396f2570 4#include "dir.h"
fc59e748 5#include "lockfile.h"
396f2570 6#include "packfile.h"
4d80560c 7#include "object-store.h"
3715a633 8#include "sha1-lookup.h"
a3407730
DS
9#include "midx.h"
10
fc59e748
DS
11#define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
12#define MIDX_VERSION 1
4d80560c
DS
13#define MIDX_BYTE_FILE_VERSION 4
14#define MIDX_BYTE_HASH_VERSION 5
15#define MIDX_BYTE_NUM_CHUNKS 6
16#define MIDX_BYTE_NUM_PACKS 8
fc59e748
DS
17#define MIDX_HASH_VERSION 1
18#define MIDX_HEADER_SIZE 12
4d80560c
DS
19#define MIDX_HASH_LEN 20
20#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
fc59e748 21
662148c4 22#define MIDX_MAX_CHUNKS 5
32f3c541
DS
23#define MIDX_CHUNK_ALIGNMENT 4
24#define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
d7cacf29 25#define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
0d5b3a5e 26#define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
662148c4
DS
27#define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
28#define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
32f3c541 29#define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
d7cacf29 30#define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
662148c4
DS
31#define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
32#define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
33#define MIDX_LARGE_OFFSET_NEEDED 0x80000000
32f3c541 34
fc59e748
DS
35static char *get_midx_filename(const char *object_dir)
36{
37 return xstrfmt("%s/pack/multi-pack-index", object_dir);
38}
39
2cf489a3 40struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
4d80560c
DS
41{
42 struct multi_pack_index *m = NULL;
43 int fd;
44 struct stat st;
45 size_t midx_size;
46 void *midx_map = NULL;
47 uint32_t hash_version;
48 char *midx_name = get_midx_filename(object_dir);
32f3c541 49 uint32_t i;
3227565c 50 const char *cur_pack_name;
4d80560c
DS
51
52 fd = git_open(midx_name);
53
54 if (fd < 0)
55 goto cleanup_fail;
56 if (fstat(fd, &st)) {
57 error_errno(_("failed to read %s"), midx_name);
58 goto cleanup_fail;
59 }
60
61 midx_size = xsize_t(st.st_size);
62
63 if (midx_size < MIDX_MIN_SIZE) {
64 error(_("multi-pack-index file %s is too small"), midx_name);
65 goto cleanup_fail;
66 }
67
68 FREE_AND_NULL(midx_name);
69
70 midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
71
72 FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
73 m->fd = fd;
74 m->data = midx_map;
75 m->data_len = midx_size;
2cf489a3 76 m->local = local;
4d80560c
DS
77
78 m->signature = get_be32(m->data);
53ad0407
DS
79 if (m->signature != MIDX_SIGNATURE)
80 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
4d80560c 81 m->signature, MIDX_SIGNATURE);
4d80560c
DS
82
83 m->version = m->data[MIDX_BYTE_FILE_VERSION];
53ad0407
DS
84 if (m->version != MIDX_VERSION)
85 die(_("multi-pack-index version %d not recognized"),
4d80560c 86 m->version);
4d80560c
DS
87
88 hash_version = m->data[MIDX_BYTE_HASH_VERSION];
53ad0407
DS
89 if (hash_version != MIDX_HASH_VERSION)
90 die(_("hash version %u does not match"), hash_version);
4d80560c
DS
91 m->hash_len = MIDX_HASH_LEN;
92
93 m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
94
95 m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
96
32f3c541
DS
97 for (i = 0; i < m->num_chunks; i++) {
98 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
99 MIDX_CHUNKLOOKUP_WIDTH * i);
100 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
101 MIDX_CHUNKLOOKUP_WIDTH * i);
102
103 switch (chunk_id) {
104 case MIDX_CHUNKID_PACKNAMES:
105 m->chunk_pack_names = m->data + chunk_offset;
106 break;
107
d7cacf29
DS
108 case MIDX_CHUNKID_OIDFANOUT:
109 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
110 break;
111
0d5b3a5e
DS
112 case MIDX_CHUNKID_OIDLOOKUP:
113 m->chunk_oid_lookup = m->data + chunk_offset;
114 break;
115
662148c4
DS
116 case MIDX_CHUNKID_OBJECTOFFSETS:
117 m->chunk_object_offsets = m->data + chunk_offset;
118 break;
119
120 case MIDX_CHUNKID_LARGEOFFSETS:
121 m->chunk_large_offsets = m->data + chunk_offset;
122 break;
123
32f3c541
DS
124 case 0:
125 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
126 break;
127
128 default:
129 /*
130 * Do nothing on unrecognized chunks, allowing future
131 * extensions to add optional chunks.
132 */
133 break;
134 }
135 }
136
137 if (!m->chunk_pack_names)
138 die(_("multi-pack-index missing required pack-name chunk"));
d7cacf29
DS
139 if (!m->chunk_oid_fanout)
140 die(_("multi-pack-index missing required OID fanout chunk"));
0d5b3a5e
DS
141 if (!m->chunk_oid_lookup)
142 die(_("multi-pack-index missing required OID lookup chunk"));
662148c4
DS
143 if (!m->chunk_object_offsets)
144 die(_("multi-pack-index missing required object offsets chunk"));
32f3c541 145
d7cacf29
DS
146 m->num_objects = ntohl(m->chunk_oid_fanout[255]);
147
3227565c 148 m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
3715a633 149 m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
3227565c
DS
150
151 cur_pack_name = (const char *)m->chunk_pack_names;
152 for (i = 0; i < m->num_packs; i++) {
153 m->pack_names[i] = cur_pack_name;
154
155 cur_pack_name += strlen(cur_pack_name) + 1;
156
157 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0) {
158 error(_("multi-pack-index pack names out of order: '%s' before '%s'"),
159 m->pack_names[i - 1],
160 m->pack_names[i]);
161 goto cleanup_fail;
162 }
163 }
164
4d80560c
DS
165 return m;
166
167cleanup_fail:
168 free(m);
169 free(midx_name);
170 if (midx_map)
171 munmap(midx_map, midx_size);
172 if (0 <= fd)
173 close(fd);
174 return NULL;
175}
176
a40498a1
DS
177static void close_midx(struct multi_pack_index *m)
178{
179 uint32_t i;
180 munmap((unsigned char *)m->data, m->data_len);
181 close(m->fd);
182 m->fd = -1;
183
184 for (i = 0; i < m->num_packs; i++) {
185 if (m->packs[i]) {
186 close_pack(m->packs[i]);
187 free(m->packs);
188 }
189 }
190 FREE_AND_NULL(m->packs);
191 FREE_AND_NULL(m->pack_names);
192}
193
0bff5269 194int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
3715a633
DS
195{
196 struct strbuf pack_name = STRBUF_INIT;
197
198 if (pack_int_id >= m->num_packs)
199 BUG("bad pack-int-id");
200
201 if (m->packs[pack_int_id])
202 return 0;
203
204 strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
205 m->pack_names[pack_int_id]);
206
2cf489a3 207 m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local);
3715a633
DS
208 strbuf_release(&pack_name);
209 return !m->packs[pack_int_id];
210}
211
212int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
213{
214 return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
215 MIDX_HASH_LEN, result);
216}
217
8aac67a1
DS
218struct object_id *nth_midxed_object_oid(struct object_id *oid,
219 struct multi_pack_index *m,
220 uint32_t n)
221{
222 if (n >= m->num_objects)
223 return NULL;
224
225 hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
226 return oid;
227}
228
3715a633
DS
229static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
230{
231 const unsigned char *offset_data;
232 uint32_t offset32;
233
234 offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
235 offset32 = get_be32(offset_data + sizeof(uint32_t));
236
237 if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
238 if (sizeof(offset32) < sizeof(uint64_t))
239 die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
240
241 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
242 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
243 }
244
245 return offset32;
246}
247
248static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
249{
250 return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
251}
252
253static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
254{
255 uint32_t pack_int_id;
256 struct packed_git *p;
257
258 if (pos >= m->num_objects)
259 return 0;
260
261 pack_int_id = nth_midxed_pack_int_id(m, pos);
262
263 if (prepare_midx_pack(m, pack_int_id))
264 die(_("error preparing packfile from multi-pack-index"));
265 p = m->packs[pack_int_id];
266
267 /*
268 * We are about to tell the caller where they can locate the
269 * requested object. We better make sure the packfile is
270 * still here and can be accessed before supplying that
271 * answer, as it may have been deleted since the MIDX was
272 * loaded!
273 */
274 if (!is_pack_valid(p))
275 return 0;
276
c39b02ae
DS
277 if (p->num_bad_objects) {
278 uint32_t i;
279 struct object_id oid;
280 nth_midxed_object_oid(&oid, m, pos);
281 for (i = 0; i < p->num_bad_objects; i++)
282 if (!hashcmp(oid.hash,
283 p->bad_object_sha1 + the_hash_algo->rawsz * i))
284 return 0;
285 }
286
3715a633
DS
287 e->offset = nth_midxed_offset(m, pos);
288 e->p = p;
289
290 return 1;
291}
292
293int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
294{
295 uint32_t pos;
296
297 if (!bsearch_midx(oid, m, &pos))
298 return 0;
299
300 return nth_midxed_pack_entry(m, e, pos);
301}
302
a40498a1
DS
303int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
304{
305 uint32_t first = 0, last = m->num_packs;
306
307 while (first < last) {
308 uint32_t mid = first + (last - first) / 2;
309 const char *current;
310 int cmp;
311
312 current = m->pack_names[mid];
313 cmp = strcmp(idx_name, current);
314 if (!cmp)
315 return 1;
316 if (cmp > 0) {
317 first = mid + 1;
318 continue;
319 }
320 last = mid;
321 }
322
323 return 0;
324}
325
2cf489a3 326int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
c4d25228 327{
29e2016b 328 struct multi_pack_index *m;
c4d25228
DS
329 struct multi_pack_index *m_search;
330 int config_value;
331
332 if (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
333 !config_value)
334 return 0;
335
29e2016b 336 for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
c4d25228
DS
337 if (!strcmp(object_dir, m_search->object_dir))
338 return 1;
339
29e2016b 340 m = load_multi_pack_index(object_dir, local);
c4d25228 341
29e2016b
DS
342 if (m) {
343 m->next = r->objects->multi_pack_index;
344 r->objects->multi_pack_index = m;
c4d25228
DS
345 return 1;
346 }
347
348 return 0;
349}
350
fc59e748
DS
351static size_t write_midx_header(struct hashfile *f,
352 unsigned char num_chunks,
353 uint32_t num_packs)
354{
355 unsigned char byte_values[4];
356
357 hashwrite_be32(f, MIDX_SIGNATURE);
358 byte_values[0] = MIDX_VERSION;
359 byte_values[1] = MIDX_HASH_VERSION;
360 byte_values[2] = num_chunks;
361 byte_values[3] = 0; /* unused */
362 hashwrite(f, byte_values, sizeof(byte_values));
363 hashwrite_be32(f, num_packs);
364
365 return MIDX_HEADER_SIZE;
366}
367
396f2570
DS
368struct pack_list {
369 struct packed_git **list;
32f3c541 370 char **names;
396f2570
DS
371 uint32_t nr;
372 uint32_t alloc_list;
32f3c541
DS
373 uint32_t alloc_names;
374 size_t pack_name_concat_len;
a40498a1 375 struct multi_pack_index *m;
396f2570
DS
376};
377
378static void add_pack_to_midx(const char *full_path, size_t full_path_len,
379 const char *file_name, void *data)
380{
381 struct pack_list *packs = (struct pack_list *)data;
382
383 if (ends_with(file_name, ".idx")) {
a40498a1
DS
384 if (packs->m && midx_contains_pack(packs->m, file_name))
385 return;
386
396f2570 387 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
32f3c541 388 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
396f2570
DS
389
390 packs->list[packs->nr] = add_packed_git(full_path,
391 full_path_len,
392 0);
fe1ed56f 393
396f2570
DS
394 if (!packs->list[packs->nr]) {
395 warning(_("failed to add packfile '%s'"),
396 full_path);
397 return;
398 }
399
fe1ed56f
DS
400 if (open_pack_index(packs->list[packs->nr])) {
401 warning(_("failed to open pack-index '%s'"),
402 full_path);
403 close_pack(packs->list[packs->nr]);
404 FREE_AND_NULL(packs->list[packs->nr]);
405 return;
406 }
407
32f3c541
DS
408 packs->names[packs->nr] = xstrdup(file_name);
409 packs->pack_name_concat_len += strlen(file_name) + 1;
396f2570
DS
410 packs->nr++;
411 }
412}
413
32f3c541
DS
414struct pack_pair {
415 uint32_t pack_int_id;
416 char *pack_name;
417};
418
419static int pack_pair_compare(const void *_a, const void *_b)
420{
421 struct pack_pair *a = (struct pack_pair *)_a;
422 struct pack_pair *b = (struct pack_pair *)_b;
423 return strcmp(a->pack_name, b->pack_name);
424}
425
426static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
427{
428 uint32_t i;
429 struct pack_pair *pairs;
430
431 ALLOC_ARRAY(pairs, nr_packs);
432
433 for (i = 0; i < nr_packs; i++) {
434 pairs[i].pack_int_id = i;
435 pairs[i].pack_name = pack_names[i];
436 }
437
438 QSORT(pairs, nr_packs, pack_pair_compare);
439
440 for (i = 0; i < nr_packs; i++) {
441 pack_names[i] = pairs[i].pack_name;
442 perm[pairs[i].pack_int_id] = i;
443 }
444
445 free(pairs);
446}
447
fe1ed56f
DS
448struct pack_midx_entry {
449 struct object_id oid;
450 uint32_t pack_int_id;
451 time_t pack_mtime;
452 uint64_t offset;
453};
454
455static int midx_oid_compare(const void *_a, const void *_b)
456{
457 const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
458 const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
459 int cmp = oidcmp(&a->oid, &b->oid);
460
461 if (cmp)
462 return cmp;
463
464 if (a->pack_mtime > b->pack_mtime)
465 return -1;
466 else if (a->pack_mtime < b->pack_mtime)
467 return 1;
468
469 return a->pack_int_id - b->pack_int_id;
470}
471
a40498a1
DS
472static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
473 uint32_t *pack_perm,
474 struct pack_midx_entry *e,
475 uint32_t pos)
476{
477 if (pos >= m->num_objects)
478 return 1;
479
480 nth_midxed_object_oid(&e->oid, m, pos);
481 e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
482 e->offset = nth_midxed_offset(m, pos);
483
484 /* consider objects in midx to be from "old" packs */
485 e->pack_mtime = 0;
486 return 0;
487}
488
fe1ed56f
DS
489static void fill_pack_entry(uint32_t pack_int_id,
490 struct packed_git *p,
491 uint32_t cur_object,
492 struct pack_midx_entry *entry)
493{
494 if (!nth_packed_object_oid(&entry->oid, p, cur_object))
495 die(_("failed to locate object %d in packfile"), cur_object);
496
497 entry->pack_int_id = pack_int_id;
498 entry->pack_mtime = p->mtime;
499
500 entry->offset = nth_packed_object_offset(p, cur_object);
501}
502
503/*
504 * It is possible to artificially get into a state where there are many
505 * duplicate copies of objects. That can create high memory pressure if
506 * we are to create a list of all objects before de-duplication. To reduce
507 * this memory pressure without a significant performance drop, automatically
508 * group objects by the first byte of their object id. Use the IDX fanout
509 * tables to group the data, copy to a local array, then sort.
510 *
511 * Copy only the de-duplicated entries (selected by most-recent modified time
512 * of a packfile containing the object).
513 */
a40498a1
DS
514static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
515 struct packed_git **p,
fe1ed56f
DS
516 uint32_t *perm,
517 uint32_t nr_packs,
518 uint32_t *nr_objects)
519{
520 uint32_t cur_fanout, cur_pack, cur_object;
521 uint32_t alloc_fanout, alloc_objects, total_objects = 0;
522 struct pack_midx_entry *entries_by_fanout = NULL;
523 struct pack_midx_entry *deduplicated_entries = NULL;
a40498a1 524 uint32_t start_pack = m ? m->num_packs : 0;
fe1ed56f 525
a40498a1 526 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
fe1ed56f
DS
527 total_objects += p[cur_pack]->num_objects;
528
529 /*
530 * As we de-duplicate by fanout value, we expect the fanout
531 * slices to be evenly distributed, with some noise. Hence,
532 * allocate slightly more than one 256th.
533 */
534 alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
535
536 ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
537 ALLOC_ARRAY(deduplicated_entries, alloc_objects);
538 *nr_objects = 0;
539
540 for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
541 uint32_t nr_fanout = 0;
542
a40498a1
DS
543 if (m) {
544 uint32_t start = 0, end;
545
546 if (cur_fanout)
547 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
548 end = ntohl(m->chunk_oid_fanout[cur_fanout]);
549
550 for (cur_object = start; cur_object < end; cur_object++) {
551 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
552 nth_midxed_pack_midx_entry(m, perm,
553 &entries_by_fanout[nr_fanout],
554 cur_object);
555 nr_fanout++;
556 }
557 }
558
559 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
fe1ed56f
DS
560 uint32_t start = 0, end;
561
562 if (cur_fanout)
563 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
564 end = get_pack_fanout(p[cur_pack], cur_fanout);
565
566 for (cur_object = start; cur_object < end; cur_object++) {
567 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
568 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
569 nr_fanout++;
570 }
571 }
572
573 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
574
575 /*
576 * The batch is now sorted by OID and then mtime (descending).
577 * Take only the first duplicate.
578 */
579 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
580 if (cur_object && !oidcmp(&entries_by_fanout[cur_object - 1].oid,
581 &entries_by_fanout[cur_object].oid))
582 continue;
583
584 ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
585 memcpy(&deduplicated_entries[*nr_objects],
586 &entries_by_fanout[cur_object],
587 sizeof(struct pack_midx_entry));
588 (*nr_objects)++;
589 }
590 }
591
592 free(entries_by_fanout);
593 return deduplicated_entries;
594}
595
32f3c541
DS
596static size_t write_midx_pack_names(struct hashfile *f,
597 char **pack_names,
598 uint32_t num_packs)
599{
600 uint32_t i;
601 unsigned char padding[MIDX_CHUNK_ALIGNMENT];
602 size_t written = 0;
603
604 for (i = 0; i < num_packs; i++) {
605 size_t writelen = strlen(pack_names[i]) + 1;
606
607 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
608 BUG("incorrect pack-file order: %s before %s",
609 pack_names[i - 1],
610 pack_names[i]);
611
612 hashwrite(f, pack_names[i], writelen);
613 written += writelen;
614 }
615
616 /* add padding to be aligned */
617 i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
618 if (i < MIDX_CHUNK_ALIGNMENT) {
619 memset(padding, 0, sizeof(padding));
620 hashwrite(f, padding, i);
621 written += i;
622 }
623
624 return written;
625}
626
d7cacf29
DS
627static size_t write_midx_oid_fanout(struct hashfile *f,
628 struct pack_midx_entry *objects,
629 uint32_t nr_objects)
630{
631 struct pack_midx_entry *list = objects;
632 struct pack_midx_entry *last = objects + nr_objects;
633 uint32_t count = 0;
634 uint32_t i;
635
636 /*
637 * Write the first-level table (the list is sorted,
638 * but we use a 256-entry lookup to be able to avoid
639 * having to do eight extra binary search iterations).
640 */
641 for (i = 0; i < 256; i++) {
642 struct pack_midx_entry *next = list;
643
644 while (next < last && next->oid.hash[0] == i) {
645 count++;
646 next++;
647 }
648
649 hashwrite_be32(f, count);
650 list = next;
651 }
652
653 return MIDX_CHUNK_FANOUT_SIZE;
654}
655
0d5b3a5e
DS
656static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
657 struct pack_midx_entry *objects,
658 uint32_t nr_objects)
659{
660 struct pack_midx_entry *list = objects;
661 uint32_t i;
662 size_t written = 0;
663
664 for (i = 0; i < nr_objects; i++) {
665 struct pack_midx_entry *obj = list++;
666
667 if (i < nr_objects - 1) {
668 struct pack_midx_entry *next = list;
669 if (oidcmp(&obj->oid, &next->oid) >= 0)
670 BUG("OIDs not in order: %s >= %s",
671 oid_to_hex(&obj->oid),
672 oid_to_hex(&next->oid));
673 }
674
675 hashwrite(f, obj->oid.hash, (int)hash_len);
676 written += hash_len;
677 }
678
679 return written;
680}
681
662148c4
DS
682static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
683 struct pack_midx_entry *objects, uint32_t nr_objects)
684{
685 struct pack_midx_entry *list = objects;
686 uint32_t i, nr_large_offset = 0;
687 size_t written = 0;
688
689 for (i = 0; i < nr_objects; i++) {
690 struct pack_midx_entry *obj = list++;
691
692 hashwrite_be32(f, obj->pack_int_id);
693
694 if (large_offset_needed && obj->offset >> 31)
695 hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
696 else if (!large_offset_needed && obj->offset >> 32)
697 BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
698 oid_to_hex(&obj->oid),
699 obj->offset);
700 else
701 hashwrite_be32(f, (uint32_t)obj->offset);
702
703 written += MIDX_CHUNK_OFFSET_WIDTH;
704 }
705
706 return written;
707}
708
709static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
710 struct pack_midx_entry *objects, uint32_t nr_objects)
711{
712 struct pack_midx_entry *list = objects;
713 size_t written = 0;
714
715 while (nr_large_offset) {
716 struct pack_midx_entry *obj = list++;
717 uint64_t offset = obj->offset;
718
719 if (!(offset >> 31))
720 continue;
721
722 hashwrite_be32(f, offset >> 32);
723 hashwrite_be32(f, offset & 0xffffffffUL);
724 written += 2 * sizeof(uint32_t);
725
726 nr_large_offset--;
727 }
728
729 return written;
730}
731
a3407730
DS
732int write_midx_file(const char *object_dir)
733{
32f3c541 734 unsigned char cur_chunk, num_chunks = 0;
fc59e748 735 char *midx_name;
396f2570 736 uint32_t i;
fc59e748
DS
737 struct hashfile *f = NULL;
738 struct lock_file lk;
396f2570 739 struct pack_list packs;
32f3c541
DS
740 uint32_t *pack_perm = NULL;
741 uint64_t written = 0;
742 uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
743 uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
662148c4 744 uint32_t nr_entries, num_large_offsets = 0;
fe1ed56f 745 struct pack_midx_entry *entries = NULL;
662148c4 746 int large_offsets_needed = 0;
fc59e748
DS
747
748 midx_name = get_midx_filename(object_dir);
749 if (safe_create_leading_directories(midx_name)) {
750 UNLEAK(midx_name);
751 die_errno(_("unable to create leading directories of %s"),
752 midx_name);
753 }
754
2cf489a3 755 packs.m = load_multi_pack_index(object_dir, 1);
a40498a1 756
396f2570 757 packs.nr = 0;
a40498a1
DS
758 packs.alloc_list = packs.m ? packs.m->num_packs : 16;
759 packs.alloc_names = packs.alloc_list;
396f2570 760 packs.list = NULL;
a40498a1 761 packs.names = NULL;
32f3c541 762 packs.pack_name_concat_len = 0;
396f2570 763 ALLOC_ARRAY(packs.list, packs.alloc_list);
32f3c541 764 ALLOC_ARRAY(packs.names, packs.alloc_names);
396f2570 765
a40498a1
DS
766 if (packs.m) {
767 for (i = 0; i < packs.m->num_packs; i++) {
768 ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
769 ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
770
771 packs.list[packs.nr] = NULL;
772 packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
773 packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
774 packs.nr++;
775 }
776 }
777
396f2570
DS
778 for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
779
a40498a1
DS
780 if (packs.m && packs.nr == packs.m->num_packs)
781 goto cleanup;
782
32f3c541
DS
783 if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
784 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
785 (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
786
787 ALLOC_ARRAY(pack_perm, packs.nr);
788 sort_packs_by_name(packs.names, packs.nr, pack_perm);
789
a40498a1
DS
790 entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
791
662148c4
DS
792 for (i = 0; i < nr_entries; i++) {
793 if (entries[i].offset > 0x7fffffff)
794 num_large_offsets++;
795 if (entries[i].offset > 0xffffffff)
796 large_offsets_needed = 1;
797 }
fe1ed56f 798
fc59e748
DS
799 hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
800 f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
801 FREE_AND_NULL(midx_name);
802
a40498a1
DS
803 if (packs.m)
804 close_midx(packs.m);
805
32f3c541 806 cur_chunk = 0;
662148c4 807 num_chunks = large_offsets_needed ? 5 : 4;
32f3c541
DS
808
809 written = write_midx_header(f, num_chunks, packs.nr);
810
811 chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
812 chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
813
814 cur_chunk++;
d7cacf29 815 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
32f3c541
DS
816 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
817
d7cacf29
DS
818 cur_chunk++;
819 chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
820 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
821
0d5b3a5e 822 cur_chunk++;
662148c4 823 chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
0d5b3a5e
DS
824 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
825
662148c4
DS
826 cur_chunk++;
827 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
828 if (large_offsets_needed) {
829 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
830
831 cur_chunk++;
832 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
833 num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
834 }
835
836 chunk_ids[cur_chunk] = 0;
837
32f3c541
DS
838 for (i = 0; i <= num_chunks; i++) {
839 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
840 BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
841 chunk_offsets[i - 1],
842 chunk_offsets[i]);
843
844 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
845 BUG("chunk offset %"PRIu64" is not properly aligned",
846 chunk_offsets[i]);
847
848 hashwrite_be32(f, chunk_ids[i]);
849 hashwrite_be32(f, chunk_offsets[i] >> 32);
850 hashwrite_be32(f, chunk_offsets[i]);
851
852 written += MIDX_CHUNKLOOKUP_WIDTH;
853 }
854
855 for (i = 0; i < num_chunks; i++) {
856 if (written != chunk_offsets[i])
857 BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
858 chunk_offsets[i],
859 written,
860 chunk_ids[i]);
861
862 switch (chunk_ids[i]) {
863 case MIDX_CHUNKID_PACKNAMES:
864 written += write_midx_pack_names(f, packs.names, packs.nr);
865 break;
866
d7cacf29
DS
867 case MIDX_CHUNKID_OIDFANOUT:
868 written += write_midx_oid_fanout(f, entries, nr_entries);
869 break;
870
0d5b3a5e
DS
871 case MIDX_CHUNKID_OIDLOOKUP:
872 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
873 break;
874
662148c4
DS
875 case MIDX_CHUNKID_OBJECTOFFSETS:
876 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
877 break;
878
879 case MIDX_CHUNKID_LARGEOFFSETS:
880 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
881 break;
882
32f3c541
DS
883 default:
884 BUG("trying to write unknown chunk id %"PRIx32,
885 chunk_ids[i]);
886 }
887 }
888
889 if (written != chunk_offsets[num_chunks])
890 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
891 written,
892 chunk_offsets[num_chunks]);
fc59e748
DS
893
894 finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
895 commit_lock_file(&lk);
896
a40498a1 897cleanup:
396f2570
DS
898 for (i = 0; i < packs.nr; i++) {
899 if (packs.list[i]) {
900 close_pack(packs.list[i]);
901 free(packs.list[i]);
902 }
32f3c541 903 free(packs.names[i]);
396f2570
DS
904 }
905
906 free(packs.list);
32f3c541 907 free(packs.names);
fe1ed56f 908 free(entries);
a40498a1
DS
909 free(pack_perm);
910 free(midx_name);
a3407730
DS
911 return 0;
912}
525e18c0
DS
913
914void clear_midx_file(const char *object_dir)
915{
916 char *midx = get_midx_filename(object_dir);
917
918 if (remove_path(midx)) {
919 UNLEAK(midx);
920 die(_("failed to clear multi-pack-index at %s"), midx);
921 }
922
923 free(midx);
924}
56ee7ff1
DS
925
926static int verify_midx_error;
927
928int verify_midx_file(const char *object_dir)
929{
930 struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
931 verify_midx_error = 0;
932
933 if (!m)
934 return 0;
935
936 return verify_midx_error;
937}