builtin/index-pack.c

   1 #include "cache.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
  13 static const char index_pack_usage[] =
  14 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  15
  16 struct object_entry
  17 {
  18         struct pack_idx_entry idx;
  19         unsigned long size;
  20         unsigned int hdr_size;
  21         enum object_type type;
  22         enum object_type real_type;
  23         unsigned delta_depth;
  24         int base_object_no;
  25 };
  26
  27 union delta_base {
  28         unsigned char sha1[20];
  29         off_t offset;
  30 };
  31
  32 struct base_data {
  33         struct base_data *base;
  34         struct base_data *child;
  35         struct object_entry *obj;
  36         void *data;
  37         unsigned long size;
  38 };
  39
  40 /*
  41  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  42  * to memcmp() only the first 20 bytes.
  43  */
  44 #define UNION_BASE_SZ   20
  45
  46 #define FLAG_LINK (1u<<20)
  47 #define FLAG_CHECKED (1u<<21)
  48
  49 struct delta_entry
  50 {
  51         union delta_base base;
  52         int obj_no;
  53 };
  54
  55 static struct object_entry *objects;
  56 static struct delta_entry *deltas;
  57 static struct base_data *base_cache;
  58 static size_t base_cache_used;
  59 static int nr_objects;
  60 static int nr_deltas;
  61 static int nr_resolved_deltas;
  62
  63 static int from_stdin;
  64 static int strict;
  65 static int verbose;
  66
  67 static struct progress *progress;
  68
  69 /* We always read in 4kB chunks. */
  70 static unsigned char input_buffer[4096];
  71 static unsigned int input_offset, input_len;
  72 static off_t consumed_bytes;
  73 static unsigned deepest_delta;
  74 static git_SHA_CTX input_ctx;
  75 static uint32_t input_crc32;
  76 static int input_fd, output_fd, pack_fd;
  77
  78 static int mark_link(struct object *obj, int type, void *data)
  79 {
  80         if (!obj)
  81                 return -1;
  82
  83         if (type != OBJ_ANY && obj->type != type)
  84                 die("object type mismatch at %s", sha1_to_hex(obj->sha1));
  85
  86         obj->flags |= FLAG_LINK;
  87         return 0;
  88 }
  89
  90 /* The content of each linked object must have been checked
  91    or it must be already present in the object database */
  92 static void check_object(struct object *obj)
  93 {
  94         if (!obj)
  95                 return;
  96
  97         if (!(obj->flags & FLAG_LINK))
  98                 return;
  99
 100         if (!(obj->flags & FLAG_CHECKED)) {
 101                 unsigned long size;
 102                 int type = sha1_object_info(obj->sha1, &size);
 103                 if (type != obj->type || type <= 0)
 104                         die("object of unexpected type");
 105                 obj->flags |= FLAG_CHECKED;
 106                 return;
 107         }
 108 }
 109
 110 static void check_objects(void)
 111 {
 112         unsigned i, max;
 113
 114         max = get_max_object_index();
 115         for (i = 0; i < max; i++)
 116                 check_object(get_indexed_object(i));
 117 }
 118
 119
 120 /* Discard current buffer used content. */
 121 static void flush(void)
 122 {
 123         if (input_offset) {
 124                 if (output_fd >= 0)
 125                         write_or_die(output_fd, input_buffer, input_offset);
 126                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 127                 memmove(input_buffer, input_buffer + input_offset, input_len);
 128                 input_offset = 0;
 129         }
 130 }
 131
 132 /*
 133  * Make sure at least "min" bytes are available in the buffer, and
 134  * return the pointer to the buffer.
 135  */
 136 static void *fill(int min)
 137 {
 138         if (min <= input_len)
 139                 return input_buffer + input_offset;
 140         if (min > sizeof(input_buffer))
 141                 die("cannot fill %d bytes", min);
 142         flush();
 143         do {
 144                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 145                                 sizeof(input_buffer) - input_len);
 146                 if (ret <= 0) {
 147                         if (!ret)
 148                                 die("early EOF");
 149                         die_errno("read error on input");
 150                 }
 151                 input_len += ret;
 152                 if (from_stdin)
 153                         display_throughput(progress, consumed_bytes + input_len);
 154         } while (input_len < min);
 155         return input_buffer;
 156 }
 157
 158 static void use(int bytes)
 159 {
 160         if (bytes > input_len)
 161                 die("used more bytes than were available");
 162         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 163         input_len -= bytes;
 164         input_offset += bytes;
 165
 166         /* make sure off_t is sufficiently large not to wrap */
 167         if (signed_add_overflows(consumed_bytes, bytes))
 168                 die("pack too large for current definition of off_t");
 169         consumed_bytes += bytes;
 170 }
 171
 172 static const char *open_pack_file(const char *pack_name)
 173 {
 174         if (from_stdin) {
 175                 input_fd = 0;
 176                 if (!pack_name) {
 177                         static char tmpfile[PATH_MAX];
 178                         output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
 179                                                 "pack/tmp_pack_XXXXXX");
 180                         pack_name = xstrdup(tmpfile);
 181                 } else
 182                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 183                 if (output_fd < 0)
 184                         die_errno("unable to create '%s'", pack_name);
 185                 pack_fd = output_fd;
 186         } else {
 187                 input_fd = open(pack_name, O_RDONLY);
 188                 if (input_fd < 0)
 189                         die_errno("cannot open packfile '%s'", pack_name);
 190                 output_fd = -1;
 191                 pack_fd = input_fd;
 192         }
 193         git_SHA1_Init(&input_ctx);
 194         return pack_name;
 195 }
 196
 197 static void parse_pack_header(void)
 198 {
 199         struct pack_header *hdr = fill(sizeof(struct pack_header));
 200
 201         /* Header consistency check */
 202         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 203                 die("pack signature mismatch");
 204         if (!pack_version_ok(hdr->hdr_version))
 205                 die("pack version %"PRIu32" unsupported",
 206                         ntohl(hdr->hdr_version));
 207
 208         nr_objects = ntohl(hdr->hdr_entries);
 209         use(sizeof(struct pack_header));
 210 }
 211
 212 static NORETURN void bad_object(unsigned long offset, const char *format,
 213                        ...) __attribute__((format (printf, 2, 3)));
 214
 215 static void bad_object(unsigned long offset, const char *format, ...)
 216 {
 217         va_list params;
 218         char buf[1024];
 219
 220         va_start(params, format);
 221         vsnprintf(buf, sizeof(buf), format, params);
 222         va_end(params);
 223         die("pack has bad object at offset %lu: %s", offset, buf);
 224 }
 225
 226 static void free_base_data(struct base_data *c)
 227 {
 228         if (c->data) {
 229                 free(c->data);
 230                 c->data = NULL;
 231                 base_cache_used -= c->size;
 232         }
 233 }
 234
 235 static void prune_base_data(struct base_data *retain)
 236 {
 237         struct base_data *b;
 238         for (b = base_cache;
 239              base_cache_used > delta_base_cache_limit && b;
 240              b = b->child) {
 241                 if (b->data && b != retain)
 242                         free_base_data(b);
 243         }
 244 }
 245
 246 static void link_base_data(struct base_data *base, struct base_data *c)
 247 {
 248         if (base)
 249                 base->child = c;
 250         else
 251                 base_cache = c;
 252
 253         c->base = base;
 254         c->child = NULL;
 255         if (c->data)
 256                 base_cache_used += c->size;
 257         prune_base_data(c);
 258 }
 259
 260 static void unlink_base_data(struct base_data *c)
 261 {
 262         struct base_data *base = c->base;
 263         if (base)
 264                 base->child = NULL;
 265         else
 266                 base_cache = NULL;
 267         free_base_data(c);
 268 }
 269
 270 static void *unpack_entry_data(unsigned long offset, unsigned long size)
 271 {
 272         int status;
 273         z_stream stream;
 274         void *buf = xmalloc(size);
 275
 276         memset(&stream, 0, sizeof(stream));
 277         git_inflate_init(&stream);
 278         stream.next_out = buf;
 279         stream.avail_out = size;
 280
 281         do {
 282                 stream.next_in = fill(1);
 283                 stream.avail_in = input_len;
 284                 status = git_inflate(&stream, 0);
 285                 use(input_len - stream.avail_in);
 286         } while (status == Z_OK);
 287         if (stream.total_out != size || status != Z_STREAM_END)
 288                 bad_object(offset, "inflate returned %d", status);
 289         git_inflate_end(&stream);
 290         return buf;
 291 }
 292
 293 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 294 {
 295         unsigned char *p;
 296         unsigned long size, c;
 297         off_t base_offset;
 298         unsigned shift;
 299         void *data;
 300
 301         obj->idx.offset = consumed_bytes;
 302         input_crc32 = crc32(0, Z_NULL, 0);
 303
 304         p = fill(1);
 305         c = *p;
 306         use(1);
 307         obj->type = (c >> 4) & 7;
 308         size = (c & 15);
 309         shift = 4;
 310         while (c & 0x80) {
 311                 p = fill(1);
 312                 c = *p;
 313                 use(1);
 314                 size += (c & 0x7f) << shift;
 315                 shift += 7;
 316         }
 317         obj->size = size;
 318
 319         switch (obj->type) {
 320         case OBJ_REF_DELTA:
 321                 hashcpy(delta_base->sha1, fill(20));
 322                 use(20);
 323                 break;
 324         case OBJ_OFS_DELTA:
 325                 memset(delta_base, 0, sizeof(*delta_base));
 326                 p = fill(1);
 327                 c = *p;
 328                 use(1);
 329                 base_offset = c & 127;
 330                 while (c & 128) {
 331                         base_offset += 1;
 332                         if (!base_offset || MSB(base_offset, 7))
 333                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
 334                         p = fill(1);
 335                         c = *p;
 336                         use(1);
 337                         base_offset = (base_offset << 7) + (c & 127);
 338                 }
 339                 delta_base->offset = obj->idx.offset - base_offset;
 340                 if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 341                         bad_object(obj->idx.offset, "delta base offset is out of bound");
 342                 break;
 343         case OBJ_COMMIT:
 344         case OBJ_TREE:
 345         case OBJ_BLOB:
 346         case OBJ_TAG:
 347                 break;
 348         default:
 349                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 350         }
 351         obj->hdr_size = consumed_bytes - obj->idx.offset;
 352
 353         data = unpack_entry_data(obj->idx.offset, obj->size);
 354         obj->idx.crc32 = input_crc32;
 355         return data;
 356 }
 357
 358 static void *get_data_from_pack(struct object_entry *obj)
 359 {
 360         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 361         unsigned long len = obj[1].idx.offset - from;
 362         unsigned char *data, *inbuf;
 363         z_stream stream;
 364         int status;
 365
 366         data = xmalloc(obj->size);
 367         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
 368
 369         memset(&stream, 0, sizeof(stream));
 370         git_inflate_init(&stream);
 371         stream.next_out = data;
 372         stream.avail_out = obj->size;
 373
 374         do {
 375                 ssize_t n = (len < 64*1024) ? len : 64*1024;
 376                 n = pread(pack_fd, inbuf, n, from);
 377                 if (n < 0)
 378                         die_errno("cannot pread pack file");
 379                 if (!n)
 380                         die("premature end of pack file, %lu bytes missing", len);
 381                 from += n;
 382                 len -= n;
 383                 stream.next_in = inbuf;
 384                 stream.avail_in = n;
 385                 status = git_inflate(&stream, 0);
 386         } while (len && status == Z_OK && !stream.avail_in);
 387
 388         /* This has been inflated OK when first encountered, so... */
 389         if (status != Z_STREAM_END || stream.total_out != obj->size)
 390                 die("serious inflate inconsistency");
 391
 392         git_inflate_end(&stream);
 393         free(inbuf);
 394         return data;
 395 }
 396
 397 static int compare_delta_bases(const union delta_base *base1,
 398                                const union delta_base *base2,
 399                                enum object_type type1,
 400                                enum object_type type2)
 401 {
 402         int cmp = type1 - type2;
 403         if (cmp)
 404                 return cmp;
 405         return memcmp(base1, base2, UNION_BASE_SZ);
 406 }
 407
 408 static int find_delta(const union delta_base *base, enum object_type type)
 409 {
 410         int first = 0, last = nr_deltas;
 411
 412         while (first < last) {
 413                 int next = (first + last) / 2;
 414                 struct delta_entry *delta = &deltas[next];
 415                 int cmp;
 416
 417                 cmp = compare_delta_bases(base, &delta->base,
 418                                           type, objects[delta->obj_no].type);
 419                 if (!cmp)
 420                         return next;
 421                 if (cmp < 0) {
 422                         last = next;
 423                         continue;
 424                 }
 425                 first = next+1;
 426         }
 427         return -first-1;
 428 }
 429
 430 static void find_delta_children(const union delta_base *base,
 431                                 int *first_index, int *last_index,
 432                                 enum object_type type)
 433 {
 434         int first = find_delta(base, type);
 435         int last = first;
 436         int end = nr_deltas - 1;
 437
 438         if (first < 0) {
 439                 *first_index = 0;
 440                 *last_index = -1;
 441                 return;
 442         }
 443         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 444                 --first;
 445         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 446                 ++last;
 447         *first_index = first;
 448         *last_index = last;
 449 }
 450
 451 static void sha1_object(const void *data, unsigned long size,
 452                         enum object_type type, unsigned char *sha1)
 453 {
 454         hash_sha1_file(data, size, typename(type), sha1);
 455         if (has_sha1_file(sha1)) {
 456                 void *has_data;
 457                 enum object_type has_type;
 458                 unsigned long has_size;
 459                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 460                 if (!has_data)
 461                         die("cannot read existing object %s", sha1_to_hex(sha1));
 462                 if (size != has_size || type != has_type ||
 463                     memcmp(data, has_data, size) != 0)
 464                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 465                 free(has_data);
 466         }
 467         if (strict) {
 468                 if (type == OBJ_BLOB) {
 469                         struct blob *blob = lookup_blob(sha1);
 470                         if (blob)
 471                                 blob->object.flags |= FLAG_CHECKED;
 472                         else
 473                                 die("invalid blob object %s", sha1_to_hex(sha1));
 474                 } else {
 475                         struct object *obj;
 476                         int eaten;
 477                         void *buf = (void *) data;
 478
 479                         /*
 480                          * we do not need to free the memory here, as the
 481                          * buf is deleted by the caller.
 482                          */
 483                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 484                         if (!obj)
 485                                 die("invalid %s", typename(type));
 486                         if (fsck_object(obj, 1, fsck_error_function))
 487                                 die("Error in object");
 488                         if (fsck_walk(obj, mark_link, NULL))
 489                                 die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 490
 491                         if (obj->type == OBJ_TREE) {
 492                                 struct tree *item = (struct tree *) obj;
 493                                 item->buffer = NULL;
 494                         }
 495                         if (obj->type == OBJ_COMMIT) {
 496                                 struct commit *commit = (struct commit *) obj;
 497                                 commit->buffer = NULL;
 498                         }
 499                         obj->flags |= FLAG_CHECKED;
 500                 }
 501         }
 502 }
 503
 504 static int is_delta_type(enum object_type type)
 505 {
 506         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
 507 }
 508
 509 static void *get_base_data(struct base_data *c)
 510 {
 511         if (!c->data) {
 512                 struct object_entry *obj = c->obj;
 513
 514                 if (is_delta_type(obj->type)) {
 515                         void *base = get_base_data(c->base);
 516                         void *raw = get_data_from_pack(obj);
 517                         c->data = patch_delta(
 518                                 base, c->base->size,
 519                                 raw, obj->size,
 520                                 &c->size);
 521                         free(raw);
 522                         if (!c->data)
 523                                 bad_object(obj->idx.offset, "failed to apply delta");
 524                 } else {
 525                         c->data = get_data_from_pack(obj);
 526                         c->size = obj->size;
 527                 }
 528
 529                 base_cache_used += c->size;
 530                 prune_base_data(c);
 531         }
 532         return c->data;
 533 }
 534
 535 static void resolve_delta(struct object_entry *delta_obj,
 536                           struct base_data *base, struct base_data *result)
 537 {
 538         void *base_data, *delta_data;
 539
 540         delta_obj->real_type = base->obj->real_type;
 541         delta_obj->delta_depth = base->obj->delta_depth + 1;
 542         if (deepest_delta < delta_obj->delta_depth)
 543                 deepest_delta = delta_obj->delta_depth;
 544         delta_obj->base_object_no = base->obj - objects;
 545         delta_data = get_data_from_pack(delta_obj);
 546         base_data = get_base_data(base);
 547         result->obj = delta_obj;
 548         result->data = patch_delta(base_data, base->size,
 549                                    delta_data, delta_obj->size, &result->size);
 550         free(delta_data);
 551         if (!result->data)
 552                 bad_object(delta_obj->idx.offset, "failed to apply delta");
 553         sha1_object(result->data, result->size, delta_obj->real_type,
 554                     delta_obj->idx.sha1);
 555         nr_resolved_deltas++;
 556 }
 557
 558 static void find_unresolved_deltas(struct base_data *base,
 559                                    struct base_data *prev_base)
 560 {
 561         int i, ref_first, ref_last, ofs_first, ofs_last;
 562
 563         /*
 564          * This is a recursive function. Those brackets should help reducing
 565          * stack usage by limiting the scope of the delta_base union.
 566          */
 567         {
 568                 union delta_base base_spec;
 569
 570                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
 571                 find_delta_children(&base_spec,
 572                                     &ref_first, &ref_last, OBJ_REF_DELTA);
 573
 574                 memset(&base_spec, 0, sizeof(base_spec));
 575                 base_spec.offset = base->obj->idx.offset;
 576                 find_delta_children(&base_spec,
 577                                     &ofs_first, &ofs_last, OBJ_OFS_DELTA);
 578         }
 579
 580         if (ref_last == -1 && ofs_last == -1) {
 581                 free(base->data);
 582                 return;
 583         }
 584
 585         link_base_data(prev_base, base);
 586
 587         for (i = ref_first; i <= ref_last; i++) {
 588                 struct object_entry *child = objects + deltas[i].obj_no;
 589                 struct base_data result;
 590
 591                 assert(child->real_type == OBJ_REF_DELTA);
 592                 resolve_delta(child, base, &result);
 593                 if (i == ref_last && ofs_last == -1)
 594                         free_base_data(base);
 595                 find_unresolved_deltas(&result, base);
 596         }
 597
 598         for (i = ofs_first; i <= ofs_last; i++) {
 599                 struct object_entry *child = objects + deltas[i].obj_no;
 600                 struct base_data result;
 601
 602                 assert(child->real_type == OBJ_OFS_DELTA);
 603                 resolve_delta(child, base, &result);
 604                 if (i == ofs_last)
 605                         free_base_data(base);
 606                 find_unresolved_deltas(&result, base);
 607         }
 608
 609         unlink_base_data(base);
 610 }
 611
 612 static int compare_delta_entry(const void *a, const void *b)
 613 {
 614         const struct delta_entry *delta_a = a;
 615         const struct delta_entry *delta_b = b;
 616
 617         /* group by type (ref vs ofs) and then by value (sha-1 or offset) */
 618         return compare_delta_bases(&delta_a->base, &delta_b->base,
 619                                    objects[delta_a->obj_no].type,
 620                                    objects[delta_b->obj_no].type);
 621 }
 622
 623 /* Parse all objects and return the pack content SHA1 hash */
 624 static void parse_pack_objects(unsigned char *sha1)
 625 {
 626         int i;
 627         struct delta_entry *delta = deltas;
 628         struct stat st;
 629
 630         /*
 631          * First pass:
 632          * - find locations of all objects;
 633          * - calculate SHA1 of all non-delta objects;
 634          * - remember base (SHA1 or offset) for all deltas.
 635          */
 636         if (verbose)
 637                 progress = start_progress(
 638                                 from_stdin ? "Receiving objects" : "Indexing objects",
 639                                 nr_objects);
 640         for (i = 0; i < nr_objects; i++) {
 641                 struct object_entry *obj = &objects[i];
 642                 void *data = unpack_raw_entry(obj, &delta->base);
 643                 obj->real_type = obj->type;
 644                 if (is_delta_type(obj->type)) {
 645                         nr_deltas++;
 646                         delta->obj_no = i;
 647                         delta++;
 648                 } else
 649                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 650                 free(data);
 651                 display_progress(progress, i+1);
 652         }
 653         objects[i].idx.offset = consumed_bytes;
 654         stop_progress(&progress);
 655
 656         /* Check pack integrity */
 657         flush();
 658         git_SHA1_Final(sha1, &input_ctx);
 659         if (hashcmp(fill(20), sha1))
 660                 die("pack is corrupted (SHA1 mismatch)");
 661         use(20);
 662
 663         /* If input_fd is a file, we should have reached its end now. */
 664         if (fstat(input_fd, &st))
 665                 die_errno("cannot fstat packfile");
 666         if (S_ISREG(st.st_mode) &&
 667                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 668                 die("pack has junk at the end");
 669
 670         if (!nr_deltas)
 671                 return;
 672
 673         /* Sort deltas by base SHA1/offset for fast searching */
 674         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 675               compare_delta_entry);
 676
 677         /*
 678          * Second pass:
 679          * - for all non-delta objects, look if it is used as a base for
 680          *   deltas;
 681          * - if used as a base, uncompress the object and apply all deltas,
 682          *   recursively checking if the resulting object is used as a base
 683          *   for some more deltas.
 684          */
 685         if (verbose)
 686                 progress = start_progress("Resolving deltas", nr_deltas);
 687         for (i = 0; i < nr_objects; i++) {
 688                 struct object_entry *obj = &objects[i];
 689                 struct base_data base_obj;
 690
 691                 if (is_delta_type(obj->type))
 692                         continue;
 693                 base_obj.obj = obj;
 694                 base_obj.data = NULL;
 695                 find_unresolved_deltas(&base_obj, NULL);
 696                 display_progress(progress, nr_resolved_deltas);
 697         }
 698 }
 699
 700 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 701 {
 702         z_stream stream;
 703         int status;
 704         unsigned char outbuf[4096];
 705
 706         memset(&stream, 0, sizeof(stream));
 707         deflateInit(&stream, zlib_compression_level);
 708         stream.next_in = in;
 709         stream.avail_in = size;
 710
 711         do {
 712                 stream.next_out = outbuf;
 713                 stream.avail_out = sizeof(outbuf);
 714                 status = deflate(&stream, Z_FINISH);
 715                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
 716         } while (status == Z_OK);
 717
 718         if (status != Z_STREAM_END)
 719                 die("unable to deflate appended object (%d)", status);
 720         size = stream.total_out;
 721         deflateEnd(&stream);
 722         return size;
 723 }
 724
 725 static struct object_entry *append_obj_to_pack(struct sha1file *f,
 726                                const unsigned char *sha1, void *buf,
 727                                unsigned long size, enum object_type type)
 728 {
 729         struct object_entry *obj = &objects[nr_objects++];
 730         unsigned char header[10];
 731         unsigned long s = size;
 732         int n = 0;
 733         unsigned char c = (type << 4) | (s & 15);
 734         s >>= 4;
 735         while (s) {
 736                 header[n++] = c | 0x80;
 737                 c = s & 0x7f;
 738                 s >>= 7;
 739         }
 740         header[n++] = c;
 741         crc32_begin(f);
 742         sha1write(f, header, n);
 743         obj[0].size = size;
 744         obj[0].hdr_size = n;
 745         obj[0].type = type;
 746         obj[0].real_type = type;
 747         obj[1].idx.offset = obj[0].idx.offset + n;
 748         obj[1].idx.offset += write_compressed(f, buf, size);
 749         obj[0].idx.crc32 = crc32_end(f);
 750         sha1flush(f);
 751         hashcpy(obj->idx.sha1, sha1);
 752         return obj;
 753 }
 754
 755 static int delta_pos_compare(const void *_a, const void *_b)
 756 {
 757         struct delta_entry *a = *(struct delta_entry **)_a;
 758         struct delta_entry *b = *(struct delta_entry **)_b;
 759         return a->obj_no - b->obj_no;
 760 }
 761
 762 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 763 {
 764         struct delta_entry **sorted_by_pos;
 765         int i, n = 0;
 766
 767         /*
 768          * Since many unresolved deltas may well be themselves base objects
 769          * for more unresolved deltas, we really want to include the
 770          * smallest number of base objects that would cover as much delta
 771          * as possible by picking the
 772          * trunc deltas first, allowing for other deltas to resolve without
 773          * additional base objects.  Since most base objects are to be found
 774          * before deltas depending on them, a good heuristic is to start
 775          * resolving deltas in the same order as their position in the pack.
 776          */
 777         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 778         for (i = 0; i < nr_deltas; i++) {
 779                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 780                         continue;
 781                 sorted_by_pos[n++] = &deltas[i];
 782         }
 783         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 784
 785         for (i = 0; i < n; i++) {
 786                 struct delta_entry *d = sorted_by_pos[i];
 787                 enum object_type type;
 788                 struct base_data base_obj;
 789
 790                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 791                         continue;
 792                 base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 793                 if (!base_obj.data)
 794                         continue;
 795
 796                 if (check_sha1_signature(d->base.sha1, base_obj.data,
 797                                 base_obj.size, typename(type)))
 798                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 799                 base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 800                                         base_obj.data, base_obj.size, type);
 801                 find_unresolved_deltas(&base_obj, NULL);
 802                 display_progress(progress, nr_resolved_deltas);
 803         }
 804         free(sorted_by_pos);
 805 }
 806
 807 static void final(const char *final_pack_name, const char *curr_pack_name,
 808                   const char *final_index_name, const char *curr_index_name,
 809                   const char *keep_name, const char *keep_msg,
 810                   unsigned char *sha1)
 811 {
 812         const char *report = "pack";
 813         char name[PATH_MAX];
 814         int err;
 815
 816         if (!from_stdin) {
 817                 close(input_fd);
 818         } else {
 819                 fsync_or_die(output_fd, curr_pack_name);
 820                 err = close(output_fd);
 821                 if (err)
 822                         die_errno("error while closing pack file");
 823         }
 824
 825         if (keep_msg) {
 826                 int keep_fd, keep_msg_len = strlen(keep_msg);
 827
 828                 if (!keep_name)
 829                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
 830                 else
 831                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 832
 833                 if (keep_fd < 0) {
 834                         if (errno != EEXIST)
 835                                 die_errno("cannot write keep file '%s'",
 836                                           keep_name);
 837                 } else {
 838                         if (keep_msg_len > 0) {
 839                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
 840                                 write_or_die(keep_fd, "\n", 1);
 841                         }
 842                         if (close(keep_fd) != 0)
 843                                 die_errno("cannot close written keep file '%s'",
 844                                     keep_name);
 845                         report = "keep";
 846                 }
 847         }
 848
 849         if (final_pack_name != curr_pack_name) {
 850                 if (!final_pack_name) {
 851                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 852                                  get_object_directory(), sha1_to_hex(sha1));
 853                         final_pack_name = name;
 854                 }
 855                 if (move_temp_to_file(curr_pack_name, final_pack_name))
 856                         die("cannot store pack file");
 857         } else if (from_stdin)
 858                 chmod(final_pack_name, 0444);
 859
 860         if (final_index_name != curr_index_name) {
 861                 if (!final_index_name) {
 862                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 863                                  get_object_directory(), sha1_to_hex(sha1));
 864                         final_index_name = name;
 865                 }
 866                 if (move_temp_to_file(curr_index_name, final_index_name))
 867                         die("cannot store index file");
 868         } else
 869                 chmod(final_index_name, 0444);
 870
 871         if (!from_stdin) {
 872                 printf("%s\n", sha1_to_hex(sha1));
 873         } else {
 874                 char buf[48];
 875                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 876                                    report, sha1_to_hex(sha1));
 877                 write_or_die(1, buf, len);
 878
 879                 /*
 880                  * Let's just mimic git-unpack-objects here and write
 881                  * the last part of the input buffer to stdout.
 882                  */
 883                 while (input_len) {
 884                         err = xwrite(1, input_buffer + input_offset, input_len);
 885                         if (err <= 0)
 886                                 break;
 887                         input_len -= err;
 888                         input_offset += err;
 889                 }
 890         }
 891 }
 892
 893 static int git_index_pack_config(const char *k, const char *v, void *cb)
 894 {
 895         struct pack_idx_option *opts = cb;
 896
 897         if (!strcmp(k, "pack.indexversion")) {
 898                 opts->version = git_config_int(k, v);
 899                 if (opts->version > 2)
 900                         die("bad pack.indexversion=%"PRIu32, opts->version);
 901                 return 0;
 902         }
 903         return git_default_config(k, v, cb);
 904 }
 905
 906 static int cmp_uint32(const void *a_, const void *b_)
 907 {
 908         uint32_t a = *((uint32_t *)a_);
 909         uint32_t b = *((uint32_t *)b_);
 910
 911         return (a < b) ? -1 : (a != b);
 912 }
 913
 914 static void read_v2_anomalous_offsets(struct packed_git *p,
 915                                       struct pack_idx_option *opts)
 916 {
 917         const uint32_t *idx1, *idx2;
 918         uint32_t i;
 919
 920         /* The address of the 4-byte offset table */
 921         idx1 = (((const uint32_t *)p->index_data)
 922                 + 2 /* 8-byte header */
 923                 + 256 /* fan out */
 924                 + 5 * p->num_objects /* 20-byte SHA-1 table */
 925                 + p->num_objects /* CRC32 table */
 926                 );
 927
 928         /* The address of the 8-byte offset table */
 929         idx2 = idx1 + p->num_objects;
 930
 931         for (i = 0; i < p->num_objects; i++) {
 932                 uint32_t off = ntohl(idx1[i]);
 933                 if (!(off & 0x80000000))
 934                         continue;
 935                 off = off & 0x7fffffff;
 936                 if (idx2[off * 2])
 937                         continue;
 938                 /*
 939                  * The real offset is ntohl(idx2[off * 2]) in high 4
 940                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
 941                  * octets.  But idx2[off * 2] is Zero!!!
 942                  */
 943                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
 944                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
 945         }
 946
 947         if (1 < opts->anomaly_nr)
 948                 qsort(opts->anomaly, opts->anomaly_nr, sizeof(uint32_t), cmp_uint32);
 949 }
 950
 951 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
 952 {
 953         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
 954
 955         if (!p)
 956                 die("Cannot open existing pack file '%s'", pack_name);
 957         if (open_pack_index(p))
 958                 die("Cannot open existing pack idx file for '%s'", pack_name);
 959
 960         /* Read the attributes from the existing idx file */
 961         opts->version = p->index_version;
 962
 963         if (opts->version == 2)
 964                 read_v2_anomalous_offsets(p, opts);
 965
 966         /*
 967          * Get rid of the idx file as we do not need it anymore.
 968          * NEEDSWORK: extract this bit from free_pack_by_name() in
 969          * sha1_file.c, perhaps?  It shouldn't matter very much as we
 970          * know we haven't installed this pack (hence we never have
 971          * read anything from it).
 972          */
 973         close_pack_index(p);
 974         free(p);
 975 }
 976
 977 static void show_pack_info(int stat_only)
 978 {
 979         int i, baseobjects = nr_objects - nr_deltas;
 980         unsigned long *chain_histogram = NULL;
 981
 982         if (deepest_delta)
 983                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
 984
 985         for (i = 0; i < nr_objects; i++) {
 986                 struct object_entry *obj = &objects[i];
 987
 988                 if (is_delta_type(obj->type))
 989                         chain_histogram[obj->delta_depth - 1]++;
 990                 if (stat_only)
 991                         continue;
 992                 printf("%s %-6s %lu %lu %"PRIuMAX,
 993                        sha1_to_hex(obj->idx.sha1),
 994                        typename(obj->real_type), obj->size,
 995                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
 996                        (uintmax_t)obj->idx.offset);
 997                 if (is_delta_type(obj->type)) {
 998                         struct object_entry *bobj = &objects[obj->base_object_no];
 999                         printf(" %u %s", obj->delta_depth, sha1_to_hex(bobj->idx.sha1));
1000                 }
1001                 putchar('\n');
1002         }
1003
1004         if (baseobjects)
1005                 printf("non delta: %d object%s\n",
1006                        baseobjects, baseobjects > 1 ? "s" : "");
1007         for (i = 0; i < deepest_delta; i++) {
1008                 if (!chain_histogram[i])
1009                         continue;
1010                 printf("chain length = %d: %lu object%s\n",
1011                        i + 1,
1012                        chain_histogram[i],
1013                        chain_histogram[i] > 1 ? "s" : "");
1014         }
1015 }
1016
1017 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1018 {
1019         int i, fix_thin_pack = 0, verify = 0, stat_only = 0, stat = 0;
1020         const char *curr_pack, *curr_index;
1021         const char *index_name = NULL, *pack_name = NULL;
1022         const char *keep_name = NULL, *keep_msg = NULL;
1023         char *index_name_buf = NULL, *keep_name_buf = NULL;
1024         struct pack_idx_entry **idx_objects;
1025         struct pack_idx_option opts;
1026         unsigned char pack_sha1[20];
1027
1028         if (argc == 2 && !strcmp(argv[1], "-h"))
1029                 usage(index_pack_usage);
1030
1031         read_replace_refs = 0;
1032
1033         reset_pack_idx_option(&opts);
1034         git_config(git_index_pack_config, &opts);
1035         if (prefix && chdir(prefix))
1036                 die("Cannot come back to cwd");
1037
1038         for (i = 1; i < argc; i++) {
1039                 const char *arg = argv[i];
1040
1041                 if (*arg == '-') {
1042                         if (!strcmp(arg, "--stdin")) {
1043                                 from_stdin = 1;
1044                         } else if (!strcmp(arg, "--fix-thin")) {
1045                                 fix_thin_pack = 1;
1046                         } else if (!strcmp(arg, "--strict")) {
1047                                 strict = 1;
1048                         } else if (!strcmp(arg, "--verify")) {
1049                                 verify = 1;
1050                         } else if (!strcmp(arg, "--verify-stat")) {
1051                                 verify = 1;
1052                                 stat = 1;
1053                         } else if (!strcmp(arg, "--verify-stat-only")) {
1054                                 verify = 1;
1055                                 stat = 1;
1056                                 stat_only = 1;
1057                         } else if (!strcmp(arg, "--keep")) {
1058                                 keep_msg = "";
1059                         } else if (!prefixcmp(arg, "--keep=")) {
1060                                 keep_msg = arg + 7;
1061                         } else if (!prefixcmp(arg, "--pack_header=")) {
1062                                 struct pack_header *hdr;
1063                                 char *c;
1064
1065                                 hdr = (struct pack_header *)input_buffer;
1066                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1067                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1068                                 if (*c != ',')
1069                                         die("bad %s", arg);
1070                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1071                                 if (*c)
1072                                         die("bad %s", arg);
1073                                 input_len = sizeof(*hdr);
1074                         } else if (!strcmp(arg, "-v")) {
1075                                 verbose = 1;
1076                         } else if (!strcmp(arg, "-o")) {
1077                                 if (index_name || (i+1) >= argc)
1078                                         usage(index_pack_usage);
1079                                 index_name = argv[++i];
1080                         } else if (!prefixcmp(arg, "--index-version=")) {
1081                                 char *c;
1082                                 opts.version = strtoul(arg + 16, &c, 10);
1083                                 if (opts.version > 2)
1084                                         die("bad %s", arg);
1085                                 if (*c == ',')
1086                                         opts.off32_limit = strtoul(c+1, &c, 0);
1087                                 if (*c || opts.off32_limit & 0x80000000)
1088                                         die("bad %s", arg);
1089                         } else
1090                                 usage(index_pack_usage);
1091                         continue;
1092                 }
1093
1094                 if (pack_name)
1095                         usage(index_pack_usage);
1096                 pack_name = arg;
1097         }
1098
1099         if (!pack_name && !from_stdin)
1100                 usage(index_pack_usage);
1101         if (fix_thin_pack && !from_stdin)
1102                 die("--fix-thin cannot be used without --stdin");
1103         if (!index_name && pack_name) {
1104                 int len = strlen(pack_name);
1105                 if (!has_extension(pack_name, ".pack"))
1106                         die("packfile name '%s' does not end with '.pack'",
1107                             pack_name);
1108                 index_name_buf = xmalloc(len);
1109                 memcpy(index_name_buf, pack_name, len - 5);
1110                 strcpy(index_name_buf + len - 5, ".idx");
1111                 index_name = index_name_buf;
1112         }
1113         if (keep_msg && !keep_name && pack_name) {
1114                 int len = strlen(pack_name);
1115                 if (!has_extension(pack_name, ".pack"))
1116                         die("packfile name '%s' does not end with '.pack'",
1117                             pack_name);
1118                 keep_name_buf = xmalloc(len);
1119                 memcpy(keep_name_buf, pack_name, len - 5);
1120                 strcpy(keep_name_buf + len - 5, ".keep");
1121                 keep_name = keep_name_buf;
1122         }
1123         if (verify) {
1124                 if (!index_name)
1125                         die("--verify with no packfile name given");
1126                 read_idx_option(&opts, index_name);
1127                 opts.flags |= WRITE_IDX_VERIFY;
1128         }
1129
1130         curr_pack = open_pack_file(pack_name);
1131         parse_pack_header();
1132         objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
1133         deltas = xcalloc(nr_objects, sizeof(struct delta_entry));
1134         parse_pack_objects(pack_sha1);
1135         if (nr_deltas == nr_resolved_deltas) {
1136                 stop_progress(&progress);
1137                 /* Flush remaining pack final 20-byte SHA1. */
1138                 flush();
1139         } else {
1140                 if (fix_thin_pack) {
1141                         struct sha1file *f;
1142                         unsigned char read_sha1[20], tail_sha1[20];
1143                         char msg[48];
1144                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
1145                         int nr_objects_initial = nr_objects;
1146                         if (nr_unresolved <= 0)
1147                                 die("confusion beyond insanity");
1148                         objects = xrealloc(objects,
1149                                            (nr_objects + nr_unresolved + 1)
1150                                            * sizeof(*objects));
1151                         f = sha1fd(output_fd, curr_pack);
1152                         fix_unresolved_deltas(f, nr_unresolved);
1153                         sprintf(msg, "completed with %d local objects",
1154                                 nr_objects - nr_objects_initial);
1155                         stop_progress_msg(&progress, msg);
1156                         sha1close(f, tail_sha1, 0);
1157                         hashcpy(read_sha1, pack_sha1);
1158                         fixup_pack_header_footer(output_fd, pack_sha1,
1159                                                  curr_pack, nr_objects,
1160                                                  read_sha1, consumed_bytes-20);
1161                         if (hashcmp(read_sha1, tail_sha1) != 0)
1162                                 die("Unexpected tail checksum for %s "
1163                                     "(disk corruption?)", curr_pack);
1164                 }
1165                 if (nr_deltas != nr_resolved_deltas)
1166                         die("pack has %d unresolved deltas",
1167                             nr_deltas - nr_resolved_deltas);
1168         }
1169         free(deltas);
1170         if (strict)
1171                 check_objects();
1172
1173         if (stat)
1174                 show_pack_info(stat_only);
1175
1176         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1177         for (i = 0; i < nr_objects; i++)
1178                 idx_objects[i] = &objects[i].idx;
1179         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1180         free(idx_objects);
1181
1182         if (!verify)
1183                 final(pack_name, curr_pack,
1184                       index_name, curr_index,
1185                       keep_name, keep_msg,
1186                       pack_sha1);
1187         else
1188                 close(input_fd);
1189         free(objects);
1190         free(index_name_buf);
1191         free(keep_name_buf);
1192         if (pack_name == NULL)
1193                 free((void *) curr_pack);
1194         if (index_name == NULL)
1195                 free((void *) curr_index);
1196
1197         return 0;
1198 }