git.oblomov.eu Git - git/blob - builtin/index-pack.c

   1 #include "builtin.h"
   2 #include "delta.h"
   3 #include "pack.h"
   4 #include "csum-file.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "progress.h"
  10 #include "fsck.h"
  11 #include "exec_cmd.h"
  12 #include "streaming.h"
  13 #include "thread-utils.h"
  14
  15 static const char index_pack_usage[] =
  16 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  17
  18 struct object_entry {
  19         struct pack_idx_entry idx;
  20         unsigned long size;
  21         unsigned int hdr_size;
  22         enum object_type type;
  23         enum object_type real_type;
  24         unsigned delta_depth;
  25         int base_object_no;
  26 };
  27
  28 union delta_base {
  29         unsigned char sha1[20];
  30         off_t offset;
  31 };
  32
  33 struct base_data {
  34         struct base_data *base;
  35         struct base_data *child;
  36         struct object_entry *obj;
  37         void *data;
  38         unsigned long size;
  39         int ref_first, ref_last;
  40         int ofs_first, ofs_last;
  41 };
  42
  43 #if !defined(NO_PTHREADS) && defined(NO_THREAD_SAFE_PREAD)
  44 /* pread() emulation is not thread-safe. Disable threading. */
  45 #define NO_PTHREADS
  46 #endif
  47
  48 struct thread_local {
  49 #ifndef NO_PTHREADS
  50         pthread_t thread;
  51 #endif
  52         struct base_data *base_cache;
  53         size_t base_cache_used;
  54 };
  55
  56 /*
  57  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  58  * to memcmp() only the first 20 bytes.
  59  */
  60 #define UNION_BASE_SZ   20
  61
  62 #define FLAG_LINK (1u<<20)
  63 #define FLAG_CHECKED (1u<<21)
  64
  65 struct delta_entry {
  66         union delta_base base;
  67         int obj_no;
  68 };
  69
  70 static struct object_entry *objects;
  71 static struct delta_entry *deltas;
  72 static struct thread_local nothread_data;
  73 static int nr_objects;
  74 static int nr_deltas;
  75 static int nr_resolved_deltas;
  76 static int nr_threads;
  77
  78 static int from_stdin;
  79 static int strict;
  80 static int verbose;
  81
  82 static struct progress *progress;
  83
  84 /* We always read in 4kB chunks. */
  85 static unsigned char input_buffer[4096];
  86 static unsigned int input_offset, input_len;
  87 static off_t consumed_bytes;
  88 static unsigned deepest_delta;
  89 static git_SHA_CTX input_ctx;
  90 static uint32_t input_crc32;
  91 static int input_fd, output_fd, pack_fd;
  92
  93 #ifndef NO_PTHREADS
  94
  95 static struct thread_local *thread_data;
  96 static int nr_dispatched;
  97 static int threads_active;
  98
  99 static pthread_mutex_t read_mutex;
 100 #define read_lock()             lock_mutex(&read_mutex)
 101 #define read_unlock()           unlock_mutex(&read_mutex)
 102
 103 static pthread_mutex_t counter_mutex;
 104 #define counter_lock()          lock_mutex(&counter_mutex)
 105 #define counter_unlock()        unlock_mutex(&counter_mutex)
 106
 107 static pthread_mutex_t work_mutex;
 108 #define work_lock()             lock_mutex(&work_mutex)
 109 #define work_unlock()           unlock_mutex(&work_mutex)
 110
 111 static pthread_key_t key;
 112
 113 static inline void lock_mutex(pthread_mutex_t *mutex)
 114 {
 115         if (threads_active)
 116                 pthread_mutex_lock(mutex);
 117 }
 118
 119 static inline void unlock_mutex(pthread_mutex_t *mutex)
 120 {
 121         if (threads_active)
 122                 pthread_mutex_unlock(mutex);
 123 }
 124
 125 /*
 126  * Mutex and conditional variable can't be statically-initialized on Windows.
 127  */
 128 static void init_thread(void)
 129 {
 130         init_recursive_mutex(&read_mutex);
 131         pthread_mutex_init(&counter_mutex, NULL);
 132         pthread_mutex_init(&work_mutex, NULL);
 133         pthread_key_create(&key, NULL);
 134         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
 135         threads_active = 1;
 136 }
 137
 138 static void cleanup_thread(void)
 139 {
 140         if (!threads_active)
 141                 return;
 142         threads_active = 0;
 143         pthread_mutex_destroy(&read_mutex);
 144         pthread_mutex_destroy(&counter_mutex);
 145         pthread_mutex_destroy(&work_mutex);
 146         pthread_key_delete(key);
 147         free(thread_data);
 148 }
 149
 150 #else
 151
 152 #define read_lock()
 153 #define read_unlock()
 154
 155 #define counter_lock()
 156 #define counter_unlock()
 157
 158 #define work_lock()
 159 #define work_unlock()
 160
 161 #endif
 162
 163
 164 static int mark_link(struct object *obj, int type, void *data)
 165 {
 166         if (!obj)
 167                 return -1;
 168
 169         if (type != OBJ_ANY && obj->type != type)
 170                 die(_("object type mismatch at %s"), sha1_to_hex(obj->sha1));
 171
 172         obj->flags |= FLAG_LINK;
 173         return 0;
 174 }
 175
 176 /* The content of each linked object must have been checked
 177    or it must be already present in the object database */
 178 static void check_object(struct object *obj)
 179 {
 180         if (!obj)
 181                 return;
 182
 183         if (!(obj->flags & FLAG_LINK))
 184                 return;
 185
 186         if (!(obj->flags & FLAG_CHECKED)) {
 187                 unsigned long size;
 188                 int type = sha1_object_info(obj->sha1, &size);
 189                 if (type != obj->type || type <= 0)
 190                         die(_("object of unexpected type"));
 191                 obj->flags |= FLAG_CHECKED;
 192                 return;
 193         }
 194 }
 195
 196 static void check_objects(void)
 197 {
 198         unsigned i, max;
 199
 200         max = get_max_object_index();
 201         for (i = 0; i < max; i++)
 202                 check_object(get_indexed_object(i));
 203 }
 204
 205
 206 /* Discard current buffer used content. */
 207 static void flush(void)
 208 {
 209         if (input_offset) {
 210                 if (output_fd >= 0)
 211                         write_or_die(output_fd, input_buffer, input_offset);
 212                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 213                 memmove(input_buffer, input_buffer + input_offset, input_len);
 214                 input_offset = 0;
 215         }
 216 }
 217
 218 /*
 219  * Make sure at least "min" bytes are available in the buffer, and
 220  * return the pointer to the buffer.
 221  */
 222 static void *fill(int min)
 223 {
 224         if (min <= input_len)
 225                 return input_buffer + input_offset;
 226         if (min > sizeof(input_buffer))
 227                 die(Q_("cannot fill %d byte",
 228                        "cannot fill %d bytes",
 229                        min),
 230                     min);
 231         flush();
 232         do {
 233                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 234                                 sizeof(input_buffer) - input_len);
 235                 if (ret <= 0) {
 236                         if (!ret)
 237                                 die(_("early EOF"));
 238                         die_errno(_("read error on input"));
 239                 }
 240                 input_len += ret;
 241                 if (from_stdin)
 242                         display_throughput(progress, consumed_bytes + input_len);
 243         } while (input_len < min);
 244         return input_buffer;
 245 }
 246
 247 static void use(int bytes)
 248 {
 249         if (bytes > input_len)
 250                 die(_("used more bytes than were available"));
 251         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 252         input_len -= bytes;
 253         input_offset += bytes;
 254
 255         /* make sure off_t is sufficiently large not to wrap */
 256         if (signed_add_overflows(consumed_bytes, bytes))
 257                 die(_("pack too large for current definition of off_t"));
 258         consumed_bytes += bytes;
 259 }
 260
 261 static const char *open_pack_file(const char *pack_name)
 262 {
 263         if (from_stdin) {
 264                 input_fd = 0;
 265                 if (!pack_name) {
 266                         static char tmp_file[PATH_MAX];
 267                         output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
 268                                                 "pack/tmp_pack_XXXXXX");
 269                         pack_name = xstrdup(tmp_file);
 270                 } else
 271                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 272                 if (output_fd < 0)
 273                         die_errno(_("unable to create '%s'"), pack_name);
 274                 pack_fd = output_fd;
 275         } else {
 276                 input_fd = open(pack_name, O_RDONLY);
 277                 if (input_fd < 0)
 278                         die_errno(_("cannot open packfile '%s'"), pack_name);
 279                 output_fd = -1;
 280                 pack_fd = input_fd;
 281         }
 282         git_SHA1_Init(&input_ctx);
 283         return pack_name;
 284 }
 285
 286 static void parse_pack_header(void)
 287 {
 288         struct pack_header *hdr = fill(sizeof(struct pack_header));
 289
 290         /* Header consistency check */
 291         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 292                 die(_("pack signature mismatch"));
 293         if (!pack_version_ok(hdr->hdr_version))
 294                 die("pack version %"PRIu32" unsupported",
 295                         ntohl(hdr->hdr_version));
 296
 297         nr_objects = ntohl(hdr->hdr_entries);
 298         use(sizeof(struct pack_header));
 299 }
 300
 301 static NORETURN void bad_object(unsigned long offset, const char *format,
 302                        ...) __attribute__((format (printf, 2, 3)));
 303
 304 static NORETURN void bad_object(unsigned long offset, const char *format, ...)
 305 {
 306         va_list params;
 307         char buf[1024];
 308
 309         va_start(params, format);
 310         vsnprintf(buf, sizeof(buf), format, params);
 311         va_end(params);
 312         die(_("pack has bad object at offset %lu: %s"), offset, buf);
 313 }
 314
 315 static inline struct thread_local *get_thread_data(void)
 316 {
 317 #ifndef NO_PTHREADS
 318         if (threads_active)
 319                 return pthread_getspecific(key);
 320         assert(!threads_active &&
 321                "This should only be reached when all threads are gone");
 322 #endif
 323         return &nothread_data;
 324 }
 325
 326 #ifndef NO_PTHREADS
 327 static void set_thread_data(struct thread_local *data)
 328 {
 329         if (threads_active)
 330                 pthread_setspecific(key, data);
 331 }
 332 #endif
 333
 334 static struct base_data *alloc_base_data(void)
 335 {
 336         struct base_data *base = xmalloc(sizeof(struct base_data));
 337         memset(base, 0, sizeof(*base));
 338         base->ref_last = -1;
 339         base->ofs_last = -1;
 340         return base;
 341 }
 342
 343 static void free_base_data(struct base_data *c)
 344 {
 345         if (c->data) {
 346                 free(c->data);
 347                 c->data = NULL;
 348                 get_thread_data()->base_cache_used -= c->size;
 349         }
 350 }
 351
 352 static void prune_base_data(struct base_data *retain)
 353 {
 354         struct base_data *b;
 355         struct thread_local *data = get_thread_data();
 356         for (b = data->base_cache;
 357              data->base_cache_used > delta_base_cache_limit && b;
 358              b = b->child) {
 359                 if (b->data && b != retain)
 360                         free_base_data(b);
 361         }
 362 }
 363
 364 static void link_base_data(struct base_data *base, struct base_data *c)
 365 {
 366         if (base)
 367                 base->child = c;
 368         else
 369                 get_thread_data()->base_cache = c;
 370
 371         c->base = base;
 372         c->child = NULL;
 373         if (c->data)
 374                 get_thread_data()->base_cache_used += c->size;
 375         prune_base_data(c);
 376 }
 377
 378 static void unlink_base_data(struct base_data *c)
 379 {
 380         struct base_data *base = c->base;
 381         if (base)
 382                 base->child = NULL;
 383         else
 384                 get_thread_data()->base_cache = NULL;
 385         free_base_data(c);
 386 }
 387
 388 static int is_delta_type(enum object_type type)
 389 {
 390         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 391 }
 392
 393 static void *unpack_entry_data(unsigned long offset, unsigned long size,
 394                                enum object_type type, unsigned char *sha1)
 395 {
 396         static char fixed_buf[8192];
 397         int status;
 398         git_zstream stream;
 399         void *buf;
 400         git_SHA_CTX c;
 401         char hdr[32];
 402         int hdrlen;
 403
 404         if (!is_delta_type(type)) {
 405                 hdrlen = sprintf(hdr, "%s %lu", typename(type), size) + 1;
 406                 git_SHA1_Init(&c);
 407                 git_SHA1_Update(&c, hdr, hdrlen);
 408         } else
 409                 sha1 = NULL;
 410         if (type == OBJ_BLOB && size > big_file_threshold)
 411                 buf = fixed_buf;
 412         else
 413                 buf = xmalloc(size);
 414
 415         memset(&stream, 0, sizeof(stream));
 416         git_inflate_init(&stream);
 417         stream.next_out = buf;
 418         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
 419
 420         do {
 421                 unsigned char *last_out = stream.next_out;
 422                 stream.next_in = fill(1);
 423                 stream.avail_in = input_len;
 424                 status = git_inflate(&stream, 0);
 425                 use(input_len - stream.avail_in);
 426                 if (sha1)
 427                         git_SHA1_Update(&c, last_out, stream.next_out - last_out);
 428                 if (buf == fixed_buf) {
 429                         stream.next_out = buf;
 430                         stream.avail_out = sizeof(fixed_buf);
 431                 }
 432         } while (status == Z_OK);
 433         if (stream.total_out != size || status != Z_STREAM_END)
 434                 bad_object(offset, _("inflate returned %d"), status);
 435         git_inflate_end(&stream);
 436         if (sha1)
 437                 git_SHA1_Final(sha1, &c);
 438         return buf == fixed_buf ? NULL : buf;
 439 }
 440
 441 static void *unpack_raw_entry(struct object_entry *obj,
 442                               union delta_base *delta_base,
 443                               unsigned char *sha1)
 444 {
 445         unsigned char *p;
 446         unsigned long size, c;
 447         off_t base_offset;
 448         unsigned shift;
 449         void *data;
 450
 451         obj->idx.offset = consumed_bytes;
 452         input_crc32 = crc32(0, NULL, 0);
 453
 454         p = fill(1);
 455         c = *p;
 456         use(1);
 457         obj->type = (c >> 4) & 7;
 458         size = (c & 15);
 459         shift = 4;
 460         while (c & 0x80) {
 461                 p = fill(1);
 462                 c = *p;
 463                 use(1);
 464                 size += (c & 0x7f) << shift;
 465                 shift += 7;
 466         }
 467         obj->size = size;
 468
 469         switch (obj->type) {
 470         case OBJ_REF_DELTA:
 471                 hashcpy(delta_base->sha1, fill(20));
 472                 use(20);
 473                 break;
 474         case OBJ_OFS_DELTA:
 475                 memset(delta_base, 0, sizeof(*delta_base));
 476                 p = fill(1);
 477                 c = *p;
 478                 use(1);
 479                 base_offset = c & 127;
 480                 while (c & 128) {
 481                         base_offset += 1;
 482                         if (!base_offset || MSB(base_offset, 7))
 483                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
 484                         p = fill(1);
 485                         c = *p;
 486                         use(1);
 487                         base_offset = (base_offset << 7) + (c & 127);
 488                 }
 489                 delta_base->offset = obj->idx.offset - base_offset;
 490                 if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 491                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
 492                 break;
 493         case OBJ_COMMIT:
 494         case OBJ_TREE:
 495         case OBJ_BLOB:
 496         case OBJ_TAG:
 497                 break;
 498         default:
 499                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
 500         }
 501         obj->hdr_size = consumed_bytes - obj->idx.offset;
 502
 503         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, sha1);
 504         obj->idx.crc32 = input_crc32;
 505         return data;
 506 }
 507
 508 static void *unpack_data(struct object_entry *obj,
 509                          int (*consume)(const unsigned char *, unsigned long, void *),
 510                          void *cb_data)
 511 {
 512         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 513         unsigned long len = obj[1].idx.offset - from;
 514         unsigned char *data, *inbuf;
 515         git_zstream stream;
 516         int status;
 517
 518         data = xmalloc(consume ? 64*1024 : obj->size);
 519         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
 520
 521         memset(&stream, 0, sizeof(stream));
 522         git_inflate_init(&stream);
 523         stream.next_out = data;
 524         stream.avail_out = consume ? 64*1024 : obj->size;
 525
 526         do {
 527                 ssize_t n = (len < 64*1024) ? len : 64*1024;
 528                 n = pread(pack_fd, inbuf, n, from);
 529                 if (n < 0)
 530                         die_errno(_("cannot pread pack file"));
 531                 if (!n)
 532                         die(Q_("premature end of pack file, %lu byte missing",
 533                                "premature end of pack file, %lu bytes missing",
 534                                len),
 535                             len);
 536                 from += n;
 537                 len -= n;
 538                 stream.next_in = inbuf;
 539                 stream.avail_in = n;
 540                 if (!consume)
 541                         status = git_inflate(&stream, 0);
 542                 else {
 543                         do {
 544                                 status = git_inflate(&stream, 0);
 545                                 if (consume(data, stream.next_out - data, cb_data)) {
 546                                         free(inbuf);
 547                                         free(data);
 548                                         return NULL;
 549                                 }
 550                                 stream.next_out = data;
 551                                 stream.avail_out = 64*1024;
 552                         } while (status == Z_OK && stream.avail_in);
 553                 }
 554         } while (len && status == Z_OK && !stream.avail_in);
 555
 556         /* This has been inflated OK when first encountered, so... */
 557         if (status != Z_STREAM_END || stream.total_out != obj->size)
 558                 die(_("serious inflate inconsistency"));
 559
 560         git_inflate_end(&stream);
 561         free(inbuf);
 562         if (consume) {
 563                 free(data);
 564                 data = NULL;
 565         }
 566         return data;
 567 }
 568
 569 static void *get_data_from_pack(struct object_entry *obj)
 570 {
 571         return unpack_data(obj, NULL, NULL);
 572 }
 573
 574 static int compare_delta_bases(const union delta_base *base1,
 575                                const union delta_base *base2,
 576                                enum object_type type1,
 577                                enum object_type type2)
 578 {
 579         int cmp = type1 - type2;
 580         if (cmp)
 581                 return cmp;
 582         return memcmp(base1, base2, UNION_BASE_SZ);
 583 }
 584
 585 static int find_delta(const union delta_base *base, enum object_type type)
 586 {
 587         int first = 0, last = nr_deltas;
 588
 589         while (first < last) {
 590                 int next = (first + last) / 2;
 591                 struct delta_entry *delta = &deltas[next];
 592                 int cmp;
 593
 594                 cmp = compare_delta_bases(base, &delta->base,
 595                                           type, objects[delta->obj_no].type);
 596                 if (!cmp)
 597                         return next;
 598                 if (cmp < 0) {
 599                         last = next;
 600                         continue;
 601                 }
 602                 first = next+1;
 603         }
 604         return -first-1;
 605 }
 606
 607 static void find_delta_children(const union delta_base *base,
 608                                 int *first_index, int *last_index,
 609                                 enum object_type type)
 610 {
 611         int first = find_delta(base, type);
 612         int last = first;
 613         int end = nr_deltas - 1;
 614
 615         if (first < 0) {
 616                 *first_index = 0;
 617                 *last_index = -1;
 618                 return;
 619         }
 620         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 621                 --first;
 622         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 623                 ++last;
 624         *first_index = first;
 625         *last_index = last;
 626 }
 627
 628 struct compare_data {
 629         struct object_entry *entry;
 630         struct git_istream *st;
 631         unsigned char *buf;
 632         unsigned long buf_size;
 633 };
 634
 635 static int compare_objects(const unsigned char *buf, unsigned long size,
 636                            void *cb_data)
 637 {
 638         struct compare_data *data = cb_data;
 639
 640         if (data->buf_size < size) {
 641                 free(data->buf);
 642                 data->buf = xmalloc(size);
 643                 data->buf_size = size;
 644         }
 645
 646         while (size) {
 647                 ssize_t len = read_istream(data->st, data->buf, size);
 648                 if (len == 0)
 649                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 650                             sha1_to_hex(data->entry->idx.sha1));
 651                 if (len < 0)
 652                         die(_("unable to read %s"),
 653                             sha1_to_hex(data->entry->idx.sha1));
 654                 if (memcmp(buf, data->buf, len))
 655                         die(_("SHA1 COLLISION FOUND WITH %s !"),
 656                             sha1_to_hex(data->entry->idx.sha1));
 657                 size -= len;
 658                 buf += len;
 659         }
 660         return 0;
 661 }
 662
 663 static int check_collison(struct object_entry *entry)
 664 {
 665         struct compare_data data;
 666         enum object_type type;
 667         unsigned long size;
 668
 669         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
 670                 return -1;
 671
 672         memset(&data, 0, sizeof(data));
 673         data.entry = entry;
 674         data.st = open_istream(entry->idx.sha1, &type, &size, NULL);
 675         if (!data.st)
 676                 return -1;
 677         if (size != entry->size || type != entry->type)
 678                 die(_("SHA1 COLLISION FOUND WITH %s !"),
 679                     sha1_to_hex(entry->idx.sha1));
 680         unpack_data(entry, compare_objects, &data);
 681         close_istream(data.st);
 682         free(data.buf);
 683         return 0;
 684 }
 685
 686 static void sha1_object(const void *data, struct object_entry *obj_entry,
 687                         unsigned long size, enum object_type type,
 688                         const unsigned char *sha1)
 689 {
 690         void *new_data = NULL;
 691         int collision_test_needed;
 692
 693         assert(data || obj_entry);
 694
 695         read_lock();
 696         collision_test_needed = has_sha1_file(sha1);
 697         read_unlock();
 698
 699         if (collision_test_needed && !data) {
 700                 read_lock();
 701                 if (!check_collison(obj_entry))
 702                         collision_test_needed = 0;
 703                 read_unlock();
 704         }
 705         if (collision_test_needed) {
 706                 void *has_data;
 707                 enum object_type has_type;
 708                 unsigned long has_size;
 709                 read_lock();
 710                 has_type = sha1_object_info(sha1, &has_size);
 711                 if (has_type != type || has_size != size)
 712                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 713                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 714                 read_unlock();
 715                 if (!data)
 716                         data = new_data = get_data_from_pack(obj_entry);
 717                 if (!has_data)
 718                         die(_("cannot read existing object %s"), sha1_to_hex(sha1));
 719                 if (size != has_size || type != has_type ||
 720                     memcmp(data, has_data, size) != 0)
 721                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
 722                 free(has_data);
 723         }
 724
 725         if (strict) {
 726                 read_lock();
 727                 if (type == OBJ_BLOB) {
 728                         struct blob *blob = lookup_blob(sha1);
 729                         if (blob)
 730                                 blob->object.flags |= FLAG_CHECKED;
 731                         else
 732                                 die(_("invalid blob object %s"), sha1_to_hex(sha1));
 733                 } else {
 734                         struct object *obj;
 735                         int eaten;
 736                         void *buf = (void *) data;
 737
 738                         if (!buf)
 739                                 buf = new_data = get_data_from_pack(obj_entry);
 740
 741                         /*
 742                          * we do not need to free the memory here, as the
 743                          * buf is deleted by the caller.
 744                          */
 745                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 746                         if (!obj)
 747                                 die(_("invalid %s"), typename(type));
 748                         if (fsck_object(obj, 1, fsck_error_function))
 749                                 die(_("Error in object"));
 750                         if (fsck_walk(obj, mark_link, NULL))
 751                                 die(_("Not all child objects of %s are reachable"), sha1_to_hex(obj->sha1));
 752
 753                         if (obj->type == OBJ_TREE) {
 754                                 struct tree *item = (struct tree *) obj;
 755                                 item->buffer = NULL;
 756                         }
 757                         if (obj->type == OBJ_COMMIT) {
 758                                 struct commit *commit = (struct commit *) obj;
 759                                 commit->buffer = NULL;
 760                         }
 761                         obj->flags |= FLAG_CHECKED;
 762                 }
 763                 read_unlock();
 764         }
 765
 766         free(new_data);
 767 }
 768
 769 /*
 770  * This function is part of find_unresolved_deltas(). There are two
 771  * walkers going in the opposite ways.
 772  *
 773  * The first one in find_unresolved_deltas() traverses down from
 774  * parent node to children, deflating nodes along the way. However,
 775  * memory for deflated nodes is limited by delta_base_cache_limit, so
 776  * at some point parent node's deflated content may be freed.
 777  *
 778  * The second walker is this function, which goes from current node up
 779  * to top parent if necessary to deflate the node. In normal
 780  * situation, its parent node would be already deflated, so it just
 781  * needs to apply delta.
 782  *
 783  * In the worst case scenario, parent node is no longer deflated because
 784  * we're running out of delta_base_cache_limit; we need to re-deflate
 785  * parents, possibly up to the top base.
 786  *
 787  * All deflated objects here are subject to be freed if we exceed
 788  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
 789  * just need to make sure the last node is not freed.
 790  */
 791 static void *get_base_data(struct base_data *c)
 792 {
 793         if (!c->data) {
 794                 struct object_entry *obj = c->obj;
 795                 struct base_data **delta = NULL;
 796                 int delta_nr = 0, delta_alloc = 0;
 797
 798                 while (is_delta_type(c->obj->type) && !c->data) {
 799                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
 800                         delta[delta_nr++] = c;
 801                         c = c->base;
 802                 }
 803                 if (!delta_nr) {
 804                         c->data = get_data_from_pack(obj);
 805                         c->size = obj->size;
 806                         get_thread_data()->base_cache_used += c->size;
 807                         prune_base_data(c);
 808                 }
 809                 for (; delta_nr > 0; delta_nr--) {
 810                         void *base, *raw;
 811                         c = delta[delta_nr - 1];
 812                         obj = c->obj;
 813                         base = get_base_data(c->base);
 814                         raw = get_data_from_pack(obj);
 815                         c->data = patch_delta(
 816                                 base, c->base->size,
 817                                 raw, obj->size,
 818                                 &c->size);
 819                         free(raw);
 820                         if (!c->data)
 821                                 bad_object(obj->idx.offset, _("failed to apply delta"));
 822                         get_thread_data()->base_cache_used += c->size;
 823                         prune_base_data(c);
 824                 }
 825                 free(delta);
 826         }
 827         return c->data;
 828 }
 829
 830 static void resolve_delta(struct object_entry *delta_obj,
 831                           struct base_data *base, struct base_data *result)
 832 {
 833         void *base_data, *delta_data;
 834
 835         delta_obj->real_type = base->obj->real_type;
 836         delta_obj->delta_depth = base->obj->delta_depth + 1;
 837         if (deepest_delta < delta_obj->delta_depth)
 838                 deepest_delta = delta_obj->delta_depth;
 839         delta_obj->base_object_no = base->obj - objects;
 840         delta_data = get_data_from_pack(delta_obj);
 841         base_data = get_base_data(base);
 842         result->obj = delta_obj;
 843         result->data = patch_delta(base_data, base->size,
 844                                    delta_data, delta_obj->size, &result->size);
 845         free(delta_data);
 846         if (!result->data)
 847                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
 848         hash_sha1_file(result->data, result->size,
 849                        typename(delta_obj->real_type), delta_obj->idx.sha1);
 850         sha1_object(result->data, NULL, result->size, delta_obj->real_type,
 851                     delta_obj->idx.sha1);
 852         counter_lock();
 853         nr_resolved_deltas++;
 854         counter_unlock();
 855 }
 856
 857 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
 858                                                   struct base_data *prev_base)
 859 {
 860         if (base->ref_last == -1 && base->ofs_last == -1) {
 861                 union delta_base base_spec;
 862
 863                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
 864                 find_delta_children(&base_spec,
 865                                     &base->ref_first, &base->ref_last, OBJ_REF_DELTA);
 866
 867                 memset(&base_spec, 0, sizeof(base_spec));
 868                 base_spec.offset = base->obj->idx.offset;
 869                 find_delta_children(&base_spec,
 870                                     &base->ofs_first, &base->ofs_last, OBJ_OFS_DELTA);
 871
 872                 if (base->ref_last == -1 && base->ofs_last == -1) {
 873                         free(base->data);
 874                         return NULL;
 875                 }
 876
 877                 link_base_data(prev_base, base);
 878         }
 879
 880         if (base->ref_first <= base->ref_last) {
 881                 struct object_entry *child = objects + deltas[base->ref_first].obj_no;
 882                 struct base_data *result = alloc_base_data();
 883
 884                 assert(child->real_type == OBJ_REF_DELTA);
 885                 resolve_delta(child, base, result);
 886                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
 887                         free_base_data(base);
 888
 889                 base->ref_first++;
 890                 return result;
 891         }
 892
 893         if (base->ofs_first <= base->ofs_last) {
 894                 struct object_entry *child = objects + deltas[base->ofs_first].obj_no;
 895                 struct base_data *result = alloc_base_data();
 896
 897                 assert(child->real_type == OBJ_OFS_DELTA);
 898                 resolve_delta(child, base, result);
 899                 if (base->ofs_first == base->ofs_last)
 900                         free_base_data(base);
 901
 902                 base->ofs_first++;
 903                 return result;
 904         }
 905
 906         unlink_base_data(base);
 907         return NULL;
 908 }
 909
 910 static void find_unresolved_deltas(struct base_data *base)
 911 {
 912         struct base_data *new_base, *prev_base = NULL;
 913         for (;;) {
 914                 new_base = find_unresolved_deltas_1(base, prev_base);
 915
 916                 if (new_base) {
 917                         prev_base = base;
 918                         base = new_base;
 919                 } else {
 920                         free(base);
 921                         base = prev_base;
 922                         if (!base)
 923                                 return;
 924                         prev_base = base->base;
 925                 }
 926         }
 927 }
 928
 929 static int compare_delta_entry(const void *a, const void *b)
 930 {
 931         const struct delta_entry *delta_a = a;
 932         const struct delta_entry *delta_b = b;
 933
 934         /* group by type (ref vs ofs) and then by value (sha-1 or offset) */
 935         return compare_delta_bases(&delta_a->base, &delta_b->base,
 936                                    objects[delta_a->obj_no].type,
 937                                    objects[delta_b->obj_no].type);
 938 }
 939
 940 static void resolve_base(struct object_entry *obj)
 941 {
 942         struct base_data *base_obj = alloc_base_data();
 943         base_obj->obj = obj;
 944         base_obj->data = NULL;
 945         find_unresolved_deltas(base_obj);
 946 }
 947
 948 #ifndef NO_PTHREADS
 949 static void *threaded_second_pass(void *data)
 950 {
 951         set_thread_data(data);
 952         for (;;) {
 953                 int i;
 954                 work_lock();
 955                 display_progress(progress, nr_resolved_deltas);
 956                 while (nr_dispatched < nr_objects &&
 957                        is_delta_type(objects[nr_dispatched].type))
 958                         nr_dispatched++;
 959                 if (nr_dispatched >= nr_objects) {
 960                         work_unlock();
 961                         break;
 962                 }
 963                 i = nr_dispatched++;
 964                 work_unlock();
 965
 966                 resolve_base(&objects[i]);
 967         }
 968         return NULL;
 969 }
 970 #endif
 971
 972 /*
 973  * First pass:
 974  * - find locations of all objects;
 975  * - calculate SHA1 of all non-delta objects;
 976  * - remember base (SHA1 or offset) for all deltas.
 977  */
 978 static void parse_pack_objects(unsigned char *sha1)
 979 {
 980         int i, nr_delays = 0;
 981         struct delta_entry *delta = deltas;
 982         struct stat st;
 983
 984         if (verbose)
 985                 progress = start_progress(
 986                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
 987                                 nr_objects);
 988         for (i = 0; i < nr_objects; i++) {
 989                 struct object_entry *obj = &objects[i];
 990                 void *data = unpack_raw_entry(obj, &delta->base, obj->idx.sha1);
 991                 obj->real_type = obj->type;
 992                 if (is_delta_type(obj->type)) {
 993                         nr_deltas++;
 994                         delta->obj_no = i;
 995                         delta++;
 996                 } else if (!data) {
 997                         /* large blobs, check later */
 998                         obj->real_type = OBJ_BAD;
 999                         nr_delays++;
1000                 } else
1001                         sha1_object(data, NULL, obj->size, obj->type, obj->idx.sha1);
1002                 free(data);
1003                 display_progress(progress, i+1);
1004         }
1005         objects[i].idx.offset = consumed_bytes;
1006         stop_progress(&progress);
1007
1008         /* Check pack integrity */
1009         flush();
1010         git_SHA1_Final(sha1, &input_ctx);
1011         if (hashcmp(fill(20), sha1))
1012                 die(_("pack is corrupted (SHA1 mismatch)"));
1013         use(20);
1014
1015         /* If input_fd is a file, we should have reached its end now. */
1016         if (fstat(input_fd, &st))
1017                 die_errno(_("cannot fstat packfile"));
1018         if (S_ISREG(st.st_mode) &&
1019                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1020                 die(_("pack has junk at the end"));
1021
1022         for (i = 0; i < nr_objects; i++) {
1023                 struct object_entry *obj = &objects[i];
1024                 if (obj->real_type != OBJ_BAD)
1025                         continue;
1026                 obj->real_type = obj->type;
1027                 sha1_object(NULL, obj, obj->size, obj->type, obj->idx.sha1);
1028                 nr_delays--;
1029         }
1030         if (nr_delays)
1031                 die(_("confusion beyond insanity in parse_pack_objects()"));
1032 }
1033
1034 /*
1035  * Second pass:
1036  * - for all non-delta objects, look if it is used as a base for
1037  *   deltas;
1038  * - if used as a base, uncompress the object and apply all deltas,
1039  *   recursively checking if the resulting object is used as a base
1040  *   for some more deltas.
1041  */
1042 static void resolve_deltas(void)
1043 {
1044         int i;
1045
1046         if (!nr_deltas)
1047                 return;
1048
1049         /* Sort deltas by base SHA1/offset for fast searching */
1050         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
1051               compare_delta_entry);
1052
1053         if (verbose)
1054                 progress = start_progress(_("Resolving deltas"), nr_deltas);
1055
1056 #ifndef NO_PTHREADS
1057         nr_dispatched = 0;
1058         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1059                 init_thread();
1060                 for (i = 0; i < nr_threads; i++) {
1061                         int ret = pthread_create(&thread_data[i].thread, NULL,
1062                                                  threaded_second_pass, thread_data + i);
1063                         if (ret)
1064                                 die("unable to create thread: %s", strerror(ret));
1065                 }
1066                 for (i = 0; i < nr_threads; i++)
1067                         pthread_join(thread_data[i].thread, NULL);
1068                 cleanup_thread();
1069                 return;
1070         }
1071 #endif
1072
1073         for (i = 0; i < nr_objects; i++) {
1074                 struct object_entry *obj = &objects[i];
1075
1076                 if (is_delta_type(obj->type))
1077                         continue;
1078                 resolve_base(obj);
1079                 display_progress(progress, nr_resolved_deltas);
1080         }
1081 }
1082
1083 /*
1084  * Third pass:
1085  * - append objects to convert thin pack to full pack if required
1086  * - write the final 20-byte SHA-1
1087  */
1088 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved);
1089 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_sha1)
1090 {
1091         if (nr_deltas == nr_resolved_deltas) {
1092                 stop_progress(&progress);
1093                 /* Flush remaining pack final 20-byte SHA1. */
1094                 flush();
1095                 return;
1096         }
1097
1098         if (fix_thin_pack) {
1099                 struct sha1file *f;
1100                 unsigned char read_sha1[20], tail_sha1[20];
1101                 char msg[48];
1102                 int nr_unresolved = nr_deltas - nr_resolved_deltas;
1103                 int nr_objects_initial = nr_objects;
1104                 if (nr_unresolved <= 0)
1105                         die(_("confusion beyond insanity"));
1106                 objects = xrealloc(objects,
1107                                    (nr_objects + nr_unresolved + 1)
1108                                    * sizeof(*objects));
1109                 f = sha1fd(output_fd, curr_pack);
1110                 fix_unresolved_deltas(f, nr_unresolved);
1111                 sprintf(msg, "completed with %d local objects",
1112                         nr_objects - nr_objects_initial);
1113                 stop_progress_msg(&progress, msg);
1114                 sha1close(f, tail_sha1, 0);
1115                 hashcpy(read_sha1, pack_sha1);
1116                 fixup_pack_header_footer(output_fd, pack_sha1,
1117                                          curr_pack, nr_objects,
1118                                          read_sha1, consumed_bytes-20);
1119                 if (hashcmp(read_sha1, tail_sha1) != 0)
1120                         die("Unexpected tail checksum for %s "
1121                             "(disk corruption?)", curr_pack);
1122         }
1123         if (nr_deltas != nr_resolved_deltas)
1124                 die(Q_("pack has %d unresolved delta",
1125                        "pack has %d unresolved deltas",
1126                        nr_deltas - nr_resolved_deltas),
1127                     nr_deltas - nr_resolved_deltas);
1128 }
1129
1130 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
1131 {
1132         git_zstream stream;
1133         int status;
1134         unsigned char outbuf[4096];
1135
1136         memset(&stream, 0, sizeof(stream));
1137         git_deflate_init(&stream, zlib_compression_level);
1138         stream.next_in = in;
1139         stream.avail_in = size;
1140
1141         do {
1142                 stream.next_out = outbuf;
1143                 stream.avail_out = sizeof(outbuf);
1144                 status = git_deflate(&stream, Z_FINISH);
1145                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
1146         } while (status == Z_OK);
1147
1148         if (status != Z_STREAM_END)
1149                 die(_("unable to deflate appended object (%d)"), status);
1150         size = stream.total_out;
1151         git_deflate_end(&stream);
1152         return size;
1153 }
1154
1155 static struct object_entry *append_obj_to_pack(struct sha1file *f,
1156                                const unsigned char *sha1, void *buf,
1157                                unsigned long size, enum object_type type)
1158 {
1159         struct object_entry *obj = &objects[nr_objects++];
1160         unsigned char header[10];
1161         unsigned long s = size;
1162         int n = 0;
1163         unsigned char c = (type << 4) | (s & 15);
1164         s >>= 4;
1165         while (s) {
1166                 header[n++] = c | 0x80;
1167                 c = s & 0x7f;
1168                 s >>= 7;
1169         }
1170         header[n++] = c;
1171         crc32_begin(f);
1172         sha1write(f, header, n);
1173         obj[0].size = size;
1174         obj[0].hdr_size = n;
1175         obj[0].type = type;
1176         obj[0].real_type = type;
1177         obj[1].idx.offset = obj[0].idx.offset + n;
1178         obj[1].idx.offset += write_compressed(f, buf, size);
1179         obj[0].idx.crc32 = crc32_end(f);
1180         sha1flush(f);
1181         hashcpy(obj->idx.sha1, sha1);
1182         return obj;
1183 }
1184
1185 static int delta_pos_compare(const void *_a, const void *_b)
1186 {
1187         struct delta_entry *a = *(struct delta_entry **)_a;
1188         struct delta_entry *b = *(struct delta_entry **)_b;
1189         return a->obj_no - b->obj_no;
1190 }
1191
1192 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
1193 {
1194         struct delta_entry **sorted_by_pos;
1195         int i, n = 0;
1196
1197         /*
1198          * Since many unresolved deltas may well be themselves base objects
1199          * for more unresolved deltas, we really want to include the
1200          * smallest number of base objects that would cover as much delta
1201          * as possible by picking the
1202          * trunc deltas first, allowing for other deltas to resolve without
1203          * additional base objects.  Since most base objects are to be found
1204          * before deltas depending on them, a good heuristic is to start
1205          * resolving deltas in the same order as their position in the pack.
1206          */
1207         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
1208         for (i = 0; i < nr_deltas; i++) {
1209                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
1210                         continue;
1211                 sorted_by_pos[n++] = &deltas[i];
1212         }
1213         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
1214
1215         for (i = 0; i < n; i++) {
1216                 struct delta_entry *d = sorted_by_pos[i];
1217                 enum object_type type;
1218                 struct base_data *base_obj = alloc_base_data();
1219
1220                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1221                         continue;
1222                 base_obj->data = read_sha1_file(d->base.sha1, &type, &base_obj->size);
1223                 if (!base_obj->data)
1224                         continue;
1225
1226                 if (check_sha1_signature(d->base.sha1, base_obj->data,
1227                                 base_obj->size, typename(type)))
1228                         die(_("local object %s is corrupt"), sha1_to_hex(d->base.sha1));
1229                 base_obj->obj = append_obj_to_pack(f, d->base.sha1,
1230                                         base_obj->data, base_obj->size, type);
1231                 find_unresolved_deltas(base_obj);
1232                 display_progress(progress, nr_resolved_deltas);
1233         }
1234         free(sorted_by_pos);
1235 }
1236
1237 static void final(const char *final_pack_name, const char *curr_pack_name,
1238                   const char *final_index_name, const char *curr_index_name,
1239                   const char *keep_name, const char *keep_msg,
1240                   unsigned char *sha1)
1241 {
1242         const char *report = "pack";
1243         char name[PATH_MAX];
1244         int err;
1245
1246         if (!from_stdin) {
1247                 close(input_fd);
1248         } else {
1249                 fsync_or_die(output_fd, curr_pack_name);
1250                 err = close(output_fd);
1251                 if (err)
1252                         die_errno(_("error while closing pack file"));
1253         }
1254
1255         if (keep_msg) {
1256                 int keep_fd, keep_msg_len = strlen(keep_msg);
1257
1258                 if (!keep_name)
1259                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
1260                 else
1261                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
1262
1263                 if (keep_fd < 0) {
1264                         if (errno != EEXIST)
1265                                 die_errno(_("cannot write keep file '%s'"),
1266                                           keep_name);
1267                 } else {
1268                         if (keep_msg_len > 0) {
1269                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
1270                                 write_or_die(keep_fd, "\n", 1);
1271                         }
1272                         if (close(keep_fd) != 0)
1273                                 die_errno(_("cannot close written keep file '%s'"),
1274                                     keep_name);
1275                         report = "keep";
1276                 }
1277         }
1278
1279         if (final_pack_name != curr_pack_name) {
1280                 if (!final_pack_name) {
1281                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
1282                                  get_object_directory(), sha1_to_hex(sha1));
1283                         final_pack_name = name;
1284                 }
1285                 if (move_temp_to_file(curr_pack_name, final_pack_name))
1286                         die(_("cannot store pack file"));
1287         } else if (from_stdin)
1288                 chmod(final_pack_name, 0444);
1289
1290         if (final_index_name != curr_index_name) {
1291                 if (!final_index_name) {
1292                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
1293                                  get_object_directory(), sha1_to_hex(sha1));
1294                         final_index_name = name;
1295                 }
1296                 if (move_temp_to_file(curr_index_name, final_index_name))
1297                         die(_("cannot store index file"));
1298         } else
1299                 chmod(final_index_name, 0444);
1300
1301         if (!from_stdin) {
1302                 printf("%s\n", sha1_to_hex(sha1));
1303         } else {
1304                 char buf[48];
1305                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
1306                                    report, sha1_to_hex(sha1));
1307                 write_or_die(1, buf, len);
1308
1309                 /*
1310                  * Let's just mimic git-unpack-objects here and write
1311                  * the last part of the input buffer to stdout.
1312                  */
1313                 while (input_len) {
1314                         err = xwrite(1, input_buffer + input_offset, input_len);
1315                         if (err <= 0)
1316                                 break;
1317                         input_len -= err;
1318                         input_offset += err;
1319                 }
1320         }
1321 }
1322
1323 static int git_index_pack_config(const char *k, const char *v, void *cb)
1324 {
1325         struct pack_idx_option *opts = cb;
1326
1327         if (!strcmp(k, "pack.indexversion")) {
1328                 opts->version = git_config_int(k, v);
1329                 if (opts->version > 2)
1330                         die("bad pack.indexversion=%"PRIu32, opts->version);
1331                 return 0;
1332         }
1333         if (!strcmp(k, "pack.threads")) {
1334                 nr_threads = git_config_int(k, v);
1335                 if (nr_threads < 0)
1336                         die("invalid number of threads specified (%d)",
1337                             nr_threads);
1338 #ifdef NO_PTHREADS
1339                 if (nr_threads != 1)
1340                         warning("no threads support, ignoring %s", k);
1341                 nr_threads = 1;
1342 #endif
1343                 return 0;
1344         }
1345         return git_default_config(k, v, cb);
1346 }
1347
1348 static int cmp_uint32(const void *a_, const void *b_)
1349 {
1350         uint32_t a = *((uint32_t *)a_);
1351         uint32_t b = *((uint32_t *)b_);
1352
1353         return (a < b) ? -1 : (a != b);
1354 }
1355
1356 static void read_v2_anomalous_offsets(struct packed_git *p,
1357                                       struct pack_idx_option *opts)
1358 {
1359         const uint32_t *idx1, *idx2;
1360         uint32_t i;
1361
1362         /* The address of the 4-byte offset table */
1363         idx1 = (((const uint32_t *)p->index_data)
1364                 + 2 /* 8-byte header */
1365                 + 256 /* fan out */
1366                 + 5 * p->num_objects /* 20-byte SHA-1 table */
1367                 + p->num_objects /* CRC32 table */
1368                 );
1369
1370         /* The address of the 8-byte offset table */
1371         idx2 = idx1 + p->num_objects;
1372
1373         for (i = 0; i < p->num_objects; i++) {
1374                 uint32_t off = ntohl(idx1[i]);
1375                 if (!(off & 0x80000000))
1376                         continue;
1377                 off = off & 0x7fffffff;
1378                 if (idx2[off * 2])
1379                         continue;
1380                 /*
1381                  * The real offset is ntohl(idx2[off * 2]) in high 4
1382                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1383                  * octets.  But idx2[off * 2] is Zero!!!
1384                  */
1385                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1386                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1387         }
1388
1389         if (1 < opts->anomaly_nr)
1390                 qsort(opts->anomaly, opts->anomaly_nr, sizeof(uint32_t), cmp_uint32);
1391 }
1392
1393 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1394 {
1395         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1396
1397         if (!p)
1398                 die(_("Cannot open existing pack file '%s'"), pack_name);
1399         if (open_pack_index(p))
1400                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1401
1402         /* Read the attributes from the existing idx file */
1403         opts->version = p->index_version;
1404
1405         if (opts->version == 2)
1406                 read_v2_anomalous_offsets(p, opts);
1407
1408         /*
1409          * Get rid of the idx file as we do not need it anymore.
1410          * NEEDSWORK: extract this bit from free_pack_by_name() in
1411          * sha1_file.c, perhaps?  It shouldn't matter very much as we
1412          * know we haven't installed this pack (hence we never have
1413          * read anything from it).
1414          */
1415         close_pack_index(p);
1416         free(p);
1417 }
1418
1419 static void show_pack_info(int stat_only)
1420 {
1421         int i, baseobjects = nr_objects - nr_deltas;
1422         unsigned long *chain_histogram = NULL;
1423
1424         if (deepest_delta)
1425                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1426
1427         for (i = 0; i < nr_objects; i++) {
1428                 struct object_entry *obj = &objects[i];
1429
1430                 if (is_delta_type(obj->type))
1431                         chain_histogram[obj->delta_depth - 1]++;
1432                 if (stat_only)
1433                         continue;
1434                 printf("%s %-6s %lu %lu %"PRIuMAX,
1435                        sha1_to_hex(obj->idx.sha1),
1436                        typename(obj->real_type), obj->size,
1437                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1438                        (uintmax_t)obj->idx.offset);
1439                 if (is_delta_type(obj->type)) {
1440                         struct object_entry *bobj = &objects[obj->base_object_no];
1441                         printf(" %u %s", obj->delta_depth, sha1_to_hex(bobj->idx.sha1));
1442                 }
1443                 putchar('\n');
1444         }
1445
1446         if (baseobjects)
1447                 printf_ln(Q_("non delta: %d object",
1448                              "non delta: %d objects",
1449                              baseobjects),
1450                           baseobjects);
1451         for (i = 0; i < deepest_delta; i++) {
1452                 if (!chain_histogram[i])
1453                         continue;
1454                 printf_ln(Q_("chain length = %d: %lu object",
1455                              "chain length = %d: %lu objects",
1456                              chain_histogram[i]),
1457                           i + 1,
1458                           chain_histogram[i]);
1459         }
1460 }
1461
1462 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1463 {
1464         int i, fix_thin_pack = 0, verify = 0, stat_only = 0, stat = 0;
1465         const char *curr_pack, *curr_index;
1466         const char *index_name = NULL, *pack_name = NULL;
1467         const char *keep_name = NULL, *keep_msg = NULL;
1468         char *index_name_buf = NULL, *keep_name_buf = NULL;
1469         struct pack_idx_entry **idx_objects;
1470         struct pack_idx_option opts;
1471         unsigned char pack_sha1[20];
1472
1473         if (argc == 2 && !strcmp(argv[1], "-h"))
1474                 usage(index_pack_usage);
1475
1476         read_replace_refs = 0;
1477
1478         reset_pack_idx_option(&opts);
1479         git_config(git_index_pack_config, &opts);
1480         if (prefix && chdir(prefix))
1481                 die(_("Cannot come back to cwd"));
1482
1483         for (i = 1; i < argc; i++) {
1484                 const char *arg = argv[i];
1485
1486                 if (*arg == '-') {
1487                         if (!strcmp(arg, "--stdin")) {
1488                                 from_stdin = 1;
1489                         } else if (!strcmp(arg, "--fix-thin")) {
1490                                 fix_thin_pack = 1;
1491                         } else if (!strcmp(arg, "--strict")) {
1492                                 strict = 1;
1493                         } else if (!strcmp(arg, "--verify")) {
1494                                 verify = 1;
1495                         } else if (!strcmp(arg, "--verify-stat")) {
1496                                 verify = 1;
1497                                 stat = 1;
1498                         } else if (!strcmp(arg, "--verify-stat-only")) {
1499                                 verify = 1;
1500                                 stat = 1;
1501                                 stat_only = 1;
1502                         } else if (!strcmp(arg, "--keep")) {
1503                                 keep_msg = "";
1504                         } else if (!prefixcmp(arg, "--keep=")) {
1505                                 keep_msg = arg + 7;
1506                         } else if (!prefixcmp(arg, "--threads=")) {
1507                                 char *end;
1508                                 nr_threads = strtoul(arg+10, &end, 0);
1509                                 if (!arg[10] || *end || nr_threads < 0)
1510                                         usage(index_pack_usage);
1511 #ifdef NO_PTHREADS
1512                                 if (nr_threads != 1)
1513                                         warning("no threads support, "
1514                                                 "ignoring %s", arg);
1515                                 nr_threads = 1;
1516 #endif
1517                         } else if (!prefixcmp(arg, "--pack_header=")) {
1518                                 struct pack_header *hdr;
1519                                 char *c;
1520
1521                                 hdr = (struct pack_header *)input_buffer;
1522                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1523                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1524                                 if (*c != ',')
1525                                         die(_("bad %s"), arg);
1526                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1527                                 if (*c)
1528                                         die(_("bad %s"), arg);
1529                                 input_len = sizeof(*hdr);
1530                         } else if (!strcmp(arg, "-v")) {
1531                                 verbose = 1;
1532                         } else if (!strcmp(arg, "-o")) {
1533                                 if (index_name || (i+1) >= argc)
1534                                         usage(index_pack_usage);
1535                                 index_name = argv[++i];
1536                         } else if (!prefixcmp(arg, "--index-version=")) {
1537                                 char *c;
1538                                 opts.version = strtoul(arg + 16, &c, 10);
1539                                 if (opts.version > 2)
1540                                         die(_("bad %s"), arg);
1541                                 if (*c == ',')
1542                                         opts.off32_limit = strtoul(c+1, &c, 0);
1543                                 if (*c || opts.off32_limit & 0x80000000)
1544                                         die(_("bad %s"), arg);
1545                         } else
1546                                 usage(index_pack_usage);
1547                         continue;
1548                 }
1549
1550                 if (pack_name)
1551                         usage(index_pack_usage);
1552                 pack_name = arg;
1553         }
1554
1555         if (!pack_name && !from_stdin)
1556                 usage(index_pack_usage);
1557         if (fix_thin_pack && !from_stdin)
1558                 die(_("--fix-thin cannot be used without --stdin"));
1559         if (!index_name && pack_name) {
1560                 int len = strlen(pack_name);
1561                 if (!has_extension(pack_name, ".pack"))
1562                         die(_("packfile name '%s' does not end with '.pack'"),
1563                             pack_name);
1564                 index_name_buf = xmalloc(len);
1565                 memcpy(index_name_buf, pack_name, len - 5);
1566                 strcpy(index_name_buf + len - 5, ".idx");
1567                 index_name = index_name_buf;
1568         }
1569         if (keep_msg && !keep_name && pack_name) {
1570                 int len = strlen(pack_name);
1571                 if (!has_extension(pack_name, ".pack"))
1572                         die(_("packfile name '%s' does not end with '.pack'"),
1573                             pack_name);
1574                 keep_name_buf = xmalloc(len);
1575                 memcpy(keep_name_buf, pack_name, len - 5);
1576                 strcpy(keep_name_buf + len - 5, ".keep");
1577                 keep_name = keep_name_buf;
1578         }
1579         if (verify) {
1580                 if (!index_name)
1581                         die(_("--verify with no packfile name given"));
1582                 read_idx_option(&opts, index_name);
1583                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1584         }
1585         if (strict)
1586                 opts.flags |= WRITE_IDX_STRICT;
1587
1588 #ifndef NO_PTHREADS
1589         if (!nr_threads) {
1590                 nr_threads = online_cpus();
1591                 /* An experiment showed that more threads does not mean faster */
1592                 if (nr_threads > 3)
1593                         nr_threads = 3;
1594         }
1595 #endif
1596
1597         curr_pack = open_pack_file(pack_name);
1598         parse_pack_header();
1599         objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
1600         deltas = xcalloc(nr_objects, sizeof(struct delta_entry));
1601         parse_pack_objects(pack_sha1);
1602         resolve_deltas();
1603         conclude_pack(fix_thin_pack, curr_pack, pack_sha1);
1604         free(deltas);
1605         if (strict)
1606                 check_objects();
1607
1608         if (stat)
1609                 show_pack_info(stat_only);
1610
1611         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1612         for (i = 0; i < nr_objects; i++)
1613                 idx_objects[i] = &objects[i].idx;
1614         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1615         free(idx_objects);
1616
1617         if (!verify)
1618                 final(pack_name, curr_pack,
1619                       index_name, curr_index,
1620                       keep_name, keep_msg,
1621                       pack_sha1);
1622         else
1623                 close(input_fd);
1624         free(objects);
1625         free(index_name_buf);
1626         free(keep_name_buf);
1627         if (pack_name == NULL)
1628                 free((void *) curr_pack);
1629         if (index_name == NULL)
1630                 free((void *) curr_index);
1631
1632         return 0;
1633 }