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