git.oblomov.eu Git - git/blob - midx.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "csum-file.h"
   4 #include "dir.h"
   5 #include "lockfile.h"
   6 #include "packfile.h"
   7 #include "object-store.h"
   8 #include "sha1-lookup.h"
   9 #include "midx.h"
  10 #include "progress.h"
  11
  12 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
  13 #define MIDX_VERSION 1
  14 #define MIDX_BYTE_FILE_VERSION 4
  15 #define MIDX_BYTE_HASH_VERSION 5
  16 #define MIDX_BYTE_NUM_CHUNKS 6
  17 #define MIDX_BYTE_NUM_PACKS 8
  18 #define MIDX_HASH_VERSION 1
  19 #define MIDX_HEADER_SIZE 12
  20 #define MIDX_HASH_LEN 20
  21 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + MIDX_HASH_LEN)
  22
  23 #define MIDX_MAX_CHUNKS 5
  24 #define MIDX_CHUNK_ALIGNMENT 4
  25 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
  26 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
  27 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
  28 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
  29 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
  30 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
  31 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
  32 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
  33 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
  34 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
  35
  36 static char *get_midx_filename(const char *object_dir)
  37 {
  38         return xstrfmt("%s/pack/multi-pack-index", object_dir);
  39 }
  40
  41 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
  42 {
  43         struct multi_pack_index *m = NULL;
  44         int fd;
  45         struct stat st;
  46         size_t midx_size;
  47         void *midx_map = NULL;
  48         uint32_t hash_version;
  49         char *midx_name = get_midx_filename(object_dir);
  50         uint32_t i;
  51         const char *cur_pack_name;
  52
  53         fd = git_open(midx_name);
  54
  55         if (fd < 0)
  56                 goto cleanup_fail;
  57         if (fstat(fd, &st)) {
  58                 error_errno(_("failed to read %s"), midx_name);
  59                 goto cleanup_fail;
  60         }
  61
  62         midx_size = xsize_t(st.st_size);
  63
  64         if (midx_size < MIDX_MIN_SIZE) {
  65                 error(_("multi-pack-index file %s is too small"), midx_name);
  66                 goto cleanup_fail;
  67         }
  68
  69         FREE_AND_NULL(midx_name);
  70
  71         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
  72
  73         FLEX_ALLOC_MEM(m, object_dir, object_dir, strlen(object_dir));
  74         m->fd = fd;
  75         m->data = midx_map;
  76         m->data_len = midx_size;
  77         m->local = local;
  78
  79         m->signature = get_be32(m->data);
  80         if (m->signature != MIDX_SIGNATURE)
  81                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
  82                       m->signature, MIDX_SIGNATURE);
  83
  84         m->version = m->data[MIDX_BYTE_FILE_VERSION];
  85         if (m->version != MIDX_VERSION)
  86                 die(_("multi-pack-index version %d not recognized"),
  87                       m->version);
  88
  89         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
  90         if (hash_version != MIDX_HASH_VERSION)
  91                 die(_("hash version %u does not match"), hash_version);
  92         m->hash_len = MIDX_HASH_LEN;
  93
  94         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
  95
  96         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
  97
  98         for (i = 0; i < m->num_chunks; i++) {
  99                 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
 100                                              MIDX_CHUNKLOOKUP_WIDTH * i);
 101                 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
 102                                                  MIDX_CHUNKLOOKUP_WIDTH * i);
 103
 104                 if (chunk_offset >= m->data_len)
 105                         die(_("invalid chunk offset (too large)"));
 106
 107                 switch (chunk_id) {
 108                         case MIDX_CHUNKID_PACKNAMES:
 109                                 m->chunk_pack_names = m->data + chunk_offset;
 110                                 break;
 111
 112                         case MIDX_CHUNKID_OIDFANOUT:
 113                                 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
 114                                 break;
 115
 116                         case MIDX_CHUNKID_OIDLOOKUP:
 117                                 m->chunk_oid_lookup = m->data + chunk_offset;
 118                                 break;
 119
 120                         case MIDX_CHUNKID_OBJECTOFFSETS:
 121                                 m->chunk_object_offsets = m->data + chunk_offset;
 122                                 break;
 123
 124                         case MIDX_CHUNKID_LARGEOFFSETS:
 125                                 m->chunk_large_offsets = m->data + chunk_offset;
 126                                 break;
 127
 128                         case 0:
 129                                 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
 130                                 break;
 131
 132                         default:
 133                                 /*
 134                                  * Do nothing on unrecognized chunks, allowing future
 135                                  * extensions to add optional chunks.
 136                                  */
 137                                 break;
 138                 }
 139         }
 140
 141         if (!m->chunk_pack_names)
 142                 die(_("multi-pack-index missing required pack-name chunk"));
 143         if (!m->chunk_oid_fanout)
 144                 die(_("multi-pack-index missing required OID fanout chunk"));
 145         if (!m->chunk_oid_lookup)
 146                 die(_("multi-pack-index missing required OID lookup chunk"));
 147         if (!m->chunk_object_offsets)
 148                 die(_("multi-pack-index missing required object offsets chunk"));
 149
 150         m->num_objects = ntohl(m->chunk_oid_fanout[255]);
 151
 152         m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
 153         m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
 154
 155         cur_pack_name = (const char *)m->chunk_pack_names;
 156         for (i = 0; i < m->num_packs; i++) {
 157                 m->pack_names[i] = cur_pack_name;
 158
 159                 cur_pack_name += strlen(cur_pack_name) + 1;
 160
 161                 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
 162                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
 163                               m->pack_names[i - 1],
 164                               m->pack_names[i]);
 165         }
 166
 167         return m;
 168
 169 cleanup_fail:
 170         free(m);
 171         free(midx_name);
 172         if (midx_map)
 173                 munmap(midx_map, midx_size);
 174         if (0 <= fd)
 175                 close(fd);
 176         return NULL;
 177 }
 178
 179 static void close_midx(struct multi_pack_index *m)
 180 {
 181         uint32_t i;
 182         munmap((unsigned char *)m->data, m->data_len);
 183         close(m->fd);
 184         m->fd = -1;
 185
 186         for (i = 0; i < m->num_packs; i++) {
 187                 if (m->packs[i]) {
 188                         close_pack(m->packs[i]);
 189                         free(m->packs);
 190                 }
 191         }
 192         FREE_AND_NULL(m->packs);
 193         FREE_AND_NULL(m->pack_names);
 194 }
 195
 196 int prepare_midx_pack(struct multi_pack_index *m, uint32_t pack_int_id)
 197 {
 198         struct strbuf pack_name = STRBUF_INIT;
 199
 200         if (pack_int_id >= m->num_packs)
 201                 die(_("bad pack-int-id: %u (%u total packs"),
 202                     pack_int_id, m->num_packs);
 203
 204         if (m->packs[pack_int_id])
 205                 return 0;
 206
 207         strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
 208                     m->pack_names[pack_int_id]);
 209
 210         m->packs[pack_int_id] = add_packed_git(pack_name.buf, pack_name.len, m->local);
 211         strbuf_release(&pack_name);
 212         return !m->packs[pack_int_id];
 213 }
 214
 215 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
 216 {
 217         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
 218                             MIDX_HASH_LEN, result);
 219 }
 220
 221 struct object_id *nth_midxed_object_oid(struct object_id *oid,
 222                                         struct multi_pack_index *m,
 223                                         uint32_t n)
 224 {
 225         if (n >= m->num_objects)
 226                 return NULL;
 227
 228         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
 229         return oid;
 230 }
 231
 232 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
 233 {
 234         const unsigned char *offset_data;
 235         uint32_t offset32;
 236
 237         offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
 238         offset32 = get_be32(offset_data + sizeof(uint32_t));
 239
 240         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
 241                 if (sizeof(off_t) < sizeof(uint64_t))
 242                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
 243
 244                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
 245                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
 246         }
 247
 248         return offset32;
 249 }
 250
 251 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
 252 {
 253         return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
 254 }
 255
 256 static int nth_midxed_pack_entry(struct multi_pack_index *m, struct pack_entry *e, uint32_t pos)
 257 {
 258         uint32_t pack_int_id;
 259         struct packed_git *p;
 260
 261         if (pos >= m->num_objects)
 262                 return 0;
 263
 264         pack_int_id = nth_midxed_pack_int_id(m, pos);
 265
 266         if (prepare_midx_pack(m, pack_int_id))
 267                 die(_("error preparing packfile from multi-pack-index"));
 268         p = m->packs[pack_int_id];
 269
 270         /*
 271         * We are about to tell the caller where they can locate the
 272         * requested object.  We better make sure the packfile is
 273         * still here and can be accessed before supplying that
 274         * answer, as it may have been deleted since the MIDX was
 275         * loaded!
 276         */
 277         if (!is_pack_valid(p))
 278                 return 0;
 279
 280         if (p->num_bad_objects) {
 281                 uint32_t i;
 282                 struct object_id oid;
 283                 nth_midxed_object_oid(&oid, m, pos);
 284                 for (i = 0; i < p->num_bad_objects; i++)
 285                         if (hasheq(oid.hash,
 286                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
 287                                 return 0;
 288         }
 289
 290         e->offset = nth_midxed_offset(m, pos);
 291         e->p = p;
 292
 293         return 1;
 294 }
 295
 296 int fill_midx_entry(const struct object_id *oid, struct pack_entry *e, struct multi_pack_index *m)
 297 {
 298         uint32_t pos;
 299
 300         if (!bsearch_midx(oid, m, &pos))
 301                 return 0;
 302
 303         return nth_midxed_pack_entry(m, e, pos);
 304 }
 305
 306 int midx_contains_pack(struct multi_pack_index *m, const char *idx_name)
 307 {
 308         uint32_t first = 0, last = m->num_packs;
 309
 310         while (first < last) {
 311                 uint32_t mid = first + (last - first) / 2;
 312                 const char *current;
 313                 int cmp;
 314
 315                 current = m->pack_names[mid];
 316                 cmp = strcmp(idx_name, current);
 317                 if (!cmp)
 318                         return 1;
 319                 if (cmp > 0) {
 320                         first = mid + 1;
 321                         continue;
 322                 }
 323                 last = mid;
 324         }
 325
 326         return 0;
 327 }
 328
 329 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
 330 {
 331         struct multi_pack_index *m;
 332         struct multi_pack_index *m_search;
 333         int config_value;
 334
 335         if (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
 336             !config_value)
 337                 return 0;
 338
 339         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
 340                 if (!strcmp(object_dir, m_search->object_dir))
 341                         return 1;
 342
 343         m = load_multi_pack_index(object_dir, local);
 344
 345         if (m) {
 346                 m->next = r->objects->multi_pack_index;
 347                 r->objects->multi_pack_index = m;
 348                 return 1;
 349         }
 350
 351         return 0;
 352 }
 353
 354 static size_t write_midx_header(struct hashfile *f,
 355                                 unsigned char num_chunks,
 356                                 uint32_t num_packs)
 357 {
 358         unsigned char byte_values[4];
 359
 360         hashwrite_be32(f, MIDX_SIGNATURE);
 361         byte_values[0] = MIDX_VERSION;
 362         byte_values[1] = MIDX_HASH_VERSION;
 363         byte_values[2] = num_chunks;
 364         byte_values[3] = 0; /* unused */
 365         hashwrite(f, byte_values, sizeof(byte_values));
 366         hashwrite_be32(f, num_packs);
 367
 368         return MIDX_HEADER_SIZE;
 369 }
 370
 371 struct pack_list {
 372         struct packed_git **list;
 373         char **names;
 374         uint32_t nr;
 375         uint32_t alloc_list;
 376         uint32_t alloc_names;
 377         size_t pack_name_concat_len;
 378         struct multi_pack_index *m;
 379 };
 380
 381 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
 382                              const char *file_name, void *data)
 383 {
 384         struct pack_list *packs = (struct pack_list *)data;
 385
 386         if (ends_with(file_name, ".idx")) {
 387                 if (packs->m && midx_contains_pack(packs->m, file_name))
 388                         return;
 389
 390                 ALLOC_GROW(packs->list, packs->nr + 1, packs->alloc_list);
 391                 ALLOC_GROW(packs->names, packs->nr + 1, packs->alloc_names);
 392
 393                 packs->list[packs->nr] = add_packed_git(full_path,
 394                                                         full_path_len,
 395                                                         0);
 396
 397                 if (!packs->list[packs->nr]) {
 398                         warning(_("failed to add packfile '%s'"),
 399                                 full_path);
 400                         return;
 401                 }
 402
 403                 if (open_pack_index(packs->list[packs->nr])) {
 404                         warning(_("failed to open pack-index '%s'"),
 405                                 full_path);
 406                         close_pack(packs->list[packs->nr]);
 407                         FREE_AND_NULL(packs->list[packs->nr]);
 408                         return;
 409                 }
 410
 411                 packs->names[packs->nr] = xstrdup(file_name);
 412                 packs->pack_name_concat_len += strlen(file_name) + 1;
 413                 packs->nr++;
 414         }
 415 }
 416
 417 struct pack_pair {
 418         uint32_t pack_int_id;
 419         char *pack_name;
 420 };
 421
 422 static int pack_pair_compare(const void *_a, const void *_b)
 423 {
 424         struct pack_pair *a = (struct pack_pair *)_a;
 425         struct pack_pair *b = (struct pack_pair *)_b;
 426         return strcmp(a->pack_name, b->pack_name);
 427 }
 428
 429 static void sort_packs_by_name(char **pack_names, uint32_t nr_packs, uint32_t *perm)
 430 {
 431         uint32_t i;
 432         struct pack_pair *pairs;
 433
 434         ALLOC_ARRAY(pairs, nr_packs);
 435
 436         for (i = 0; i < nr_packs; i++) {
 437                 pairs[i].pack_int_id = i;
 438                 pairs[i].pack_name = pack_names[i];
 439         }
 440
 441         QSORT(pairs, nr_packs, pack_pair_compare);
 442
 443         for (i = 0; i < nr_packs; i++) {
 444                 pack_names[i] = pairs[i].pack_name;
 445                 perm[pairs[i].pack_int_id] = i;
 446         }
 447
 448         free(pairs);
 449 }
 450
 451 struct pack_midx_entry {
 452         struct object_id oid;
 453         uint32_t pack_int_id;
 454         time_t pack_mtime;
 455         uint64_t offset;
 456 };
 457
 458 static int midx_oid_compare(const void *_a, const void *_b)
 459 {
 460         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
 461         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
 462         int cmp = oidcmp(&a->oid, &b->oid);
 463
 464         if (cmp)
 465                 return cmp;
 466
 467         if (a->pack_mtime > b->pack_mtime)
 468                 return -1;
 469         else if (a->pack_mtime < b->pack_mtime)
 470                 return 1;
 471
 472         return a->pack_int_id - b->pack_int_id;
 473 }
 474
 475 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
 476                                       uint32_t *pack_perm,
 477                                       struct pack_midx_entry *e,
 478                                       uint32_t pos)
 479 {
 480         if (pos >= m->num_objects)
 481                 return 1;
 482
 483         nth_midxed_object_oid(&e->oid, m, pos);
 484         e->pack_int_id = pack_perm[nth_midxed_pack_int_id(m, pos)];
 485         e->offset = nth_midxed_offset(m, pos);
 486
 487         /* consider objects in midx to be from "old" packs */
 488         e->pack_mtime = 0;
 489         return 0;
 490 }
 491
 492 static void fill_pack_entry(uint32_t pack_int_id,
 493                             struct packed_git *p,
 494                             uint32_t cur_object,
 495                             struct pack_midx_entry *entry)
 496 {
 497         if (!nth_packed_object_oid(&entry->oid, p, cur_object))
 498                 die(_("failed to locate object %d in packfile"), cur_object);
 499
 500         entry->pack_int_id = pack_int_id;
 501         entry->pack_mtime = p->mtime;
 502
 503         entry->offset = nth_packed_object_offset(p, cur_object);
 504 }
 505
 506 /*
 507  * It is possible to artificially get into a state where there are many
 508  * duplicate copies of objects. That can create high memory pressure if
 509  * we are to create a list of all objects before de-duplication. To reduce
 510  * this memory pressure without a significant performance drop, automatically
 511  * group objects by the first byte of their object id. Use the IDX fanout
 512  * tables to group the data, copy to a local array, then sort.
 513  *
 514  * Copy only the de-duplicated entries (selected by most-recent modified time
 515  * of a packfile containing the object).
 516  */
 517 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
 518                                                   struct packed_git **p,
 519                                                   uint32_t *perm,
 520                                                   uint32_t nr_packs,
 521                                                   uint32_t *nr_objects)
 522 {
 523         uint32_t cur_fanout, cur_pack, cur_object;
 524         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
 525         struct pack_midx_entry *entries_by_fanout = NULL;
 526         struct pack_midx_entry *deduplicated_entries = NULL;
 527         uint32_t start_pack = m ? m->num_packs : 0;
 528
 529         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
 530                 total_objects += p[cur_pack]->num_objects;
 531
 532         /*
 533          * As we de-duplicate by fanout value, we expect the fanout
 534          * slices to be evenly distributed, with some noise. Hence,
 535          * allocate slightly more than one 256th.
 536          */
 537         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
 538
 539         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
 540         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
 541         *nr_objects = 0;
 542
 543         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
 544                 uint32_t nr_fanout = 0;
 545
 546                 if (m) {
 547                         uint32_t start = 0, end;
 548
 549                         if (cur_fanout)
 550                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
 551                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
 552
 553                         for (cur_object = start; cur_object < end; cur_object++) {
 554                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 555                                 nth_midxed_pack_midx_entry(m, perm,
 556                                                            &entries_by_fanout[nr_fanout],
 557                                                            cur_object);
 558                                 nr_fanout++;
 559                         }
 560                 }
 561
 562                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
 563                         uint32_t start = 0, end;
 564
 565                         if (cur_fanout)
 566                                 start = get_pack_fanout(p[cur_pack], cur_fanout - 1);
 567                         end = get_pack_fanout(p[cur_pack], cur_fanout);
 568
 569                         for (cur_object = start; cur_object < end; cur_object++) {
 570                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
 571                                 fill_pack_entry(perm[cur_pack], p[cur_pack], cur_object, &entries_by_fanout[nr_fanout]);
 572                                 nr_fanout++;
 573                         }
 574                 }
 575
 576                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
 577
 578                 /*
 579                  * The batch is now sorted by OID and then mtime (descending).
 580                  * Take only the first duplicate.
 581                  */
 582                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
 583                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
 584                                                 &entries_by_fanout[cur_object].oid))
 585                                 continue;
 586
 587                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
 588                         memcpy(&deduplicated_entries[*nr_objects],
 589                                &entries_by_fanout[cur_object],
 590                                sizeof(struct pack_midx_entry));
 591                         (*nr_objects)++;
 592                 }
 593         }
 594
 595         free(entries_by_fanout);
 596         return deduplicated_entries;
 597 }
 598
 599 static size_t write_midx_pack_names(struct hashfile *f,
 600                                     char **pack_names,
 601                                     uint32_t num_packs)
 602 {
 603         uint32_t i;
 604         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
 605         size_t written = 0;
 606
 607         for (i = 0; i < num_packs; i++) {
 608                 size_t writelen = strlen(pack_names[i]) + 1;
 609
 610                 if (i && strcmp(pack_names[i], pack_names[i - 1]) <= 0)
 611                         BUG("incorrect pack-file order: %s before %s",
 612                             pack_names[i - 1],
 613                             pack_names[i]);
 614
 615                 hashwrite(f, pack_names[i], writelen);
 616                 written += writelen;
 617         }
 618
 619         /* add padding to be aligned */
 620         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
 621         if (i < MIDX_CHUNK_ALIGNMENT) {
 622                 memset(padding, 0, sizeof(padding));
 623                 hashwrite(f, padding, i);
 624                 written += i;
 625         }
 626
 627         return written;
 628 }
 629
 630 static size_t write_midx_oid_fanout(struct hashfile *f,
 631                                     struct pack_midx_entry *objects,
 632                                     uint32_t nr_objects)
 633 {
 634         struct pack_midx_entry *list = objects;
 635         struct pack_midx_entry *last = objects + nr_objects;
 636         uint32_t count = 0;
 637         uint32_t i;
 638
 639         /*
 640         * Write the first-level table (the list is sorted,
 641         * but we use a 256-entry lookup to be able to avoid
 642         * having to do eight extra binary search iterations).
 643         */
 644         for (i = 0; i < 256; i++) {
 645                 struct pack_midx_entry *next = list;
 646
 647                 while (next < last && next->oid.hash[0] == i) {
 648                         count++;
 649                         next++;
 650                 }
 651
 652                 hashwrite_be32(f, count);
 653                 list = next;
 654         }
 655
 656         return MIDX_CHUNK_FANOUT_SIZE;
 657 }
 658
 659 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
 660                                     struct pack_midx_entry *objects,
 661                                     uint32_t nr_objects)
 662 {
 663         struct pack_midx_entry *list = objects;
 664         uint32_t i;
 665         size_t written = 0;
 666
 667         for (i = 0; i < nr_objects; i++) {
 668                 struct pack_midx_entry *obj = list++;
 669
 670                 if (i < nr_objects - 1) {
 671                         struct pack_midx_entry *next = list;
 672                         if (oidcmp(&obj->oid, &next->oid) >= 0)
 673                                 BUG("OIDs not in order: %s >= %s",
 674                                     oid_to_hex(&obj->oid),
 675                                     oid_to_hex(&next->oid));
 676                 }
 677
 678                 hashwrite(f, obj->oid.hash, (int)hash_len);
 679                 written += hash_len;
 680         }
 681
 682         return written;
 683 }
 684
 685 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
 686                                         struct pack_midx_entry *objects, uint32_t nr_objects)
 687 {
 688         struct pack_midx_entry *list = objects;
 689         uint32_t i, nr_large_offset = 0;
 690         size_t written = 0;
 691
 692         for (i = 0; i < nr_objects; i++) {
 693                 struct pack_midx_entry *obj = list++;
 694
 695                 hashwrite_be32(f, obj->pack_int_id);
 696
 697                 if (large_offset_needed && obj->offset >> 31)
 698                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
 699                 else if (!large_offset_needed && obj->offset >> 32)
 700                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
 701                             oid_to_hex(&obj->oid),
 702                             obj->offset);
 703                 else
 704                         hashwrite_be32(f, (uint32_t)obj->offset);
 705
 706                 written += MIDX_CHUNK_OFFSET_WIDTH;
 707         }
 708
 709         return written;
 710 }
 711
 712 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
 713                                        struct pack_midx_entry *objects, uint32_t nr_objects)
 714 {
 715         struct pack_midx_entry *list = objects;
 716         size_t written = 0;
 717
 718         while (nr_large_offset) {
 719                 struct pack_midx_entry *obj = list++;
 720                 uint64_t offset = obj->offset;
 721
 722                 if (!(offset >> 31))
 723                         continue;
 724
 725                 hashwrite_be32(f, offset >> 32);
 726                 hashwrite_be32(f, offset & 0xffffffffUL);
 727                 written += 2 * sizeof(uint32_t);
 728
 729                 nr_large_offset--;
 730         }
 731
 732         return written;
 733 }
 734
 735 int write_midx_file(const char *object_dir)
 736 {
 737         unsigned char cur_chunk, num_chunks = 0;
 738         char *midx_name;
 739         uint32_t i;
 740         struct hashfile *f = NULL;
 741         struct lock_file lk;
 742         struct pack_list packs;
 743         uint32_t *pack_perm = NULL;
 744         uint64_t written = 0;
 745         uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
 746         uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
 747         uint32_t nr_entries, num_large_offsets = 0;
 748         struct pack_midx_entry *entries = NULL;
 749         int large_offsets_needed = 0;
 750
 751         midx_name = get_midx_filename(object_dir);
 752         if (safe_create_leading_directories(midx_name)) {
 753                 UNLEAK(midx_name);
 754                 die_errno(_("unable to create leading directories of %s"),
 755                           midx_name);
 756         }
 757
 758         packs.m = load_multi_pack_index(object_dir, 1);
 759
 760         packs.nr = 0;
 761         packs.alloc_list = packs.m ? packs.m->num_packs : 16;
 762         packs.alloc_names = packs.alloc_list;
 763         packs.list = NULL;
 764         packs.names = NULL;
 765         packs.pack_name_concat_len = 0;
 766         ALLOC_ARRAY(packs.list, packs.alloc_list);
 767         ALLOC_ARRAY(packs.names, packs.alloc_names);
 768
 769         if (packs.m) {
 770                 for (i = 0; i < packs.m->num_packs; i++) {
 771                         ALLOC_GROW(packs.list, packs.nr + 1, packs.alloc_list);
 772                         ALLOC_GROW(packs.names, packs.nr + 1, packs.alloc_names);
 773
 774                         packs.list[packs.nr] = NULL;
 775                         packs.names[packs.nr] = xstrdup(packs.m->pack_names[i]);
 776                         packs.pack_name_concat_len += strlen(packs.names[packs.nr]) + 1;
 777                         packs.nr++;
 778                 }
 779         }
 780
 781         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
 782
 783         if (packs.m && packs.nr == packs.m->num_packs)
 784                 goto cleanup;
 785
 786         if (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
 787                 packs.pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
 788                                               (packs.pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
 789
 790         ALLOC_ARRAY(pack_perm, packs.nr);
 791         sort_packs_by_name(packs.names, packs.nr, pack_perm);
 792
 793         entries = get_sorted_entries(packs.m, packs.list, pack_perm, packs.nr, &nr_entries);
 794
 795         for (i = 0; i < nr_entries; i++) {
 796                 if (entries[i].offset > 0x7fffffff)
 797                         num_large_offsets++;
 798                 if (entries[i].offset > 0xffffffff)
 799                         large_offsets_needed = 1;
 800         }
 801
 802         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
 803         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
 804         FREE_AND_NULL(midx_name);
 805
 806         if (packs.m)
 807                 close_midx(packs.m);
 808
 809         cur_chunk = 0;
 810         num_chunks = large_offsets_needed ? 5 : 4;
 811
 812         written = write_midx_header(f, num_chunks, packs.nr);
 813
 814         chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
 815         chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
 816
 817         cur_chunk++;
 818         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
 819         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + packs.pack_name_concat_len;
 820
 821         cur_chunk++;
 822         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
 823         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
 824
 825         cur_chunk++;
 826         chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
 827         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_HASH_LEN;
 828
 829         cur_chunk++;
 830         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
 831         if (large_offsets_needed) {
 832                 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
 833
 834                 cur_chunk++;
 835                 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
 836                                            num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
 837         }
 838
 839         chunk_ids[cur_chunk] = 0;
 840
 841         for (i = 0; i <= num_chunks; i++) {
 842                 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
 843                         BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
 844                             chunk_offsets[i - 1],
 845                             chunk_offsets[i]);
 846
 847                 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
 848                         BUG("chunk offset %"PRIu64" is not properly aligned",
 849                             chunk_offsets[i]);
 850
 851                 hashwrite_be32(f, chunk_ids[i]);
 852                 hashwrite_be32(f, chunk_offsets[i] >> 32);
 853                 hashwrite_be32(f, chunk_offsets[i]);
 854
 855                 written += MIDX_CHUNKLOOKUP_WIDTH;
 856         }
 857
 858         for (i = 0; i < num_chunks; i++) {
 859                 if (written != chunk_offsets[i])
 860                         BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
 861                             chunk_offsets[i],
 862                             written,
 863                             chunk_ids[i]);
 864
 865                 switch (chunk_ids[i]) {
 866                         case MIDX_CHUNKID_PACKNAMES:
 867                                 written += write_midx_pack_names(f, packs.names, packs.nr);
 868                                 break;
 869
 870                         case MIDX_CHUNKID_OIDFANOUT:
 871                                 written += write_midx_oid_fanout(f, entries, nr_entries);
 872                                 break;
 873
 874                         case MIDX_CHUNKID_OIDLOOKUP:
 875                                 written += write_midx_oid_lookup(f, MIDX_HASH_LEN, entries, nr_entries);
 876                                 break;
 877
 878                         case MIDX_CHUNKID_OBJECTOFFSETS:
 879                                 written += write_midx_object_offsets(f, large_offsets_needed, entries, nr_entries);
 880                                 break;
 881
 882                         case MIDX_CHUNKID_LARGEOFFSETS:
 883                                 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
 884                                 break;
 885
 886                         default:
 887                                 BUG("trying to write unknown chunk id %"PRIx32,
 888                                     chunk_ids[i]);
 889                 }
 890         }
 891
 892         if (written != chunk_offsets[num_chunks])
 893                 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
 894                     written,
 895                     chunk_offsets[num_chunks]);
 896
 897         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
 898         commit_lock_file(&lk);
 899
 900 cleanup:
 901         for (i = 0; i < packs.nr; i++) {
 902                 if (packs.list[i]) {
 903                         close_pack(packs.list[i]);
 904                         free(packs.list[i]);
 905                 }
 906                 free(packs.names[i]);
 907         }
 908
 909         free(packs.list);
 910         free(packs.names);
 911         free(entries);
 912         free(pack_perm);
 913         free(midx_name);
 914         return 0;
 915 }
 916
 917 void clear_midx_file(const char *object_dir)
 918 {
 919         char *midx = get_midx_filename(object_dir);
 920
 921         if (remove_path(midx)) {
 922                 UNLEAK(midx);
 923                 die(_("failed to clear multi-pack-index at %s"), midx);
 924         }
 925
 926         free(midx);
 927 }
 928
 929 static int verify_midx_error;
 930
 931 static void midx_report(const char *fmt, ...)
 932 {
 933         va_list ap;
 934         verify_midx_error = 1;
 935         va_start(ap, fmt);
 936         vfprintf(stderr, fmt, ap);
 937         fprintf(stderr, "\n");
 938         va_end(ap);
 939 }
 940
 941 int verify_midx_file(const char *object_dir)
 942 {
 943         uint32_t i;
 944         struct progress *progress = NULL;
 945         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
 946         verify_midx_error = 0;
 947
 948         if (!m)
 949                 return 0;
 950
 951         for (i = 0; i < m->num_packs; i++) {
 952                 if (prepare_midx_pack(m, i))
 953                         midx_report("failed to load pack in position %d", i);
 954         }
 955
 956         for (i = 0; i < 255; i++) {
 957                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
 958                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
 959
 960                 if (oid_fanout1 > oid_fanout2)
 961                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
 962                                     i, oid_fanout1, oid_fanout2, i + 1);
 963         }
 964
 965         for (i = 0; i < m->num_objects - 1; i++) {
 966                 struct object_id oid1, oid2;
 967
 968                 nth_midxed_object_oid(&oid1, m, i);
 969                 nth_midxed_object_oid(&oid2, m, i + 1);
 970
 971                 if (oidcmp(&oid1, &oid2) >= 0)
 972                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
 973                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
 974         }
 975
 976         progress = start_progress(_("Verifying object offsets"), m->num_objects);
 977         for (i = 0; i < m->num_objects; i++) {
 978                 struct object_id oid;
 979                 struct pack_entry e;
 980                 off_t m_offset, p_offset;
 981
 982                 nth_midxed_object_oid(&oid, m, i);
 983                 if (!fill_midx_entry(&oid, &e, m)) {
 984                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
 985                                     i, oid_to_hex(&oid));
 986                         continue;
 987                 }
 988
 989                 if (open_pack_index(e.p)) {
 990                         midx_report(_("failed to load pack-index for packfile %s"),
 991                                     e.p->pack_name);
 992                         break;
 993                 }
 994
 995                 m_offset = e.offset;
 996                 p_offset = find_pack_entry_one(oid.hash, e.p);
 997
 998                 if (m_offset != p_offset)
 999                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1000                                     i, oid_to_hex(&oid), m_offset, p_offset);
1001
1002                 display_progress(progress, i + 1);
1003         }
1004         stop_progress(&progress);
1005
1006         return verify_midx_error;
1007 }