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
  11 static const char index_pack_usage[] =
  12 "git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
  13
  14 struct object_entry
  15 {
  16         struct pack_idx_entry idx;
  17         unsigned long size;
  18         unsigned int hdr_size;
  19         enum object_type type;
  20         enum object_type real_type;
  21 };
  22
  23 union delta_base {
  24         unsigned char sha1[20];
  25         off_t offset;
  26 };
  27
  28 /*
  29  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  30  * to memcmp() only the first 20 bytes.
  31  */
  32 #define UNION_BASE_SZ   20
  33
  34 struct delta_entry
  35 {
  36         union delta_base base;
  37         int obj_no;
  38 };
  39
  40 static struct object_entry *objects;
  41 static struct delta_entry *deltas;
  42 static int nr_objects;
  43 static int nr_deltas;
  44 static int nr_resolved_deltas;
  45
  46 static int from_stdin;
  47 static int verbose;
  48
  49 static struct progress progress;
  50
  51 /* We always read in 4kB chunks. */
  52 static unsigned char input_buffer[4096];
  53 static unsigned int input_offset, input_len;
  54 static off_t consumed_bytes;
  55 static SHA_CTX input_ctx;
  56 static uint32_t input_crc32;
  57 static int input_fd, output_fd, pack_fd;
  58
  59 /* Discard current buffer used content. */
  60 static void flush(void)
  61 {
  62         if (input_offset) {
  63                 if (output_fd >= 0)
  64                         write_or_die(output_fd, input_buffer, input_offset);
  65                 SHA1_Update(&input_ctx, input_buffer, input_offset);
  66                 memmove(input_buffer, input_buffer + input_offset, input_len);
  67                 input_offset = 0;
  68         }
  69 }
  70
  71 /*
  72  * Make sure at least "min" bytes are available in the buffer, and
  73  * return the pointer to the buffer.
  74  */
  75 static void *fill(int min)
  76 {
  77         if (min <= input_len)
  78                 return input_buffer + input_offset;
  79         if (min > sizeof(input_buffer))
  80                 die("cannot fill %d bytes", min);
  81         flush();
  82         do {
  83                 ssize_t ret = xread(input_fd, input_buffer + input_len,
  84                                 sizeof(input_buffer) - input_len);
  85                 if (ret <= 0) {
  86                         if (!ret)
  87                                 die("early EOF");
  88                         die("read error on input: %s", strerror(errno));
  89                 }
  90                 input_len += ret;
  91         } while (input_len < min);
  92         return input_buffer;
  93 }
  94
  95 static void use(int bytes)
  96 {
  97         if (bytes > input_len)
  98                 die("used more bytes than were available");
  99         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 100         input_len -= bytes;
 101         input_offset += bytes;
 102
 103         /* make sure off_t is sufficiently large not to wrap */
 104         if (consumed_bytes > consumed_bytes + bytes)
 105                 die("pack too large for current definition of off_t");
 106         consumed_bytes += bytes;
 107 }
 108
 109 static const char *open_pack_file(const char *pack_name)
 110 {
 111         if (from_stdin) {
 112                 input_fd = 0;
 113                 if (!pack_name) {
 114                         static char tmpfile[PATH_MAX];
 115                         snprintf(tmpfile, sizeof(tmpfile),
 116                                  "%s/tmp_pack_XXXXXX", get_object_directory());
 117                         output_fd = xmkstemp(tmpfile);
 118                         pack_name = xstrdup(tmpfile);
 119                 } else
 120                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 121                 if (output_fd < 0)
 122                         die("unable to create %s: %s\n", pack_name, strerror(errno));
 123                 pack_fd = output_fd;
 124         } else {
 125                 input_fd = open(pack_name, O_RDONLY);
 126                 if (input_fd < 0)
 127                         die("cannot open packfile '%s': %s",
 128                             pack_name, strerror(errno));
 129                 output_fd = -1;
 130                 pack_fd = input_fd;
 131         }
 132         SHA1_Init(&input_ctx);
 133         return pack_name;
 134 }
 135
 136 static void parse_pack_header(void)
 137 {
 138         struct pack_header *hdr = fill(sizeof(struct pack_header));
 139
 140         /* Header consistency check */
 141         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 142                 die("pack signature mismatch");
 143         if (!pack_version_ok(hdr->hdr_version))
 144                 die("pack version %d unsupported", ntohl(hdr->hdr_version));
 145
 146         nr_objects = ntohl(hdr->hdr_entries);
 147         use(sizeof(struct pack_header));
 148 }
 149
 150 static void bad_object(unsigned long offset, const char *format,
 151                        ...) NORETURN __attribute__((format (printf, 2, 3)));
 152
 153 static void bad_object(unsigned long offset, const char *format, ...)
 154 {
 155         va_list params;
 156         char buf[1024];
 157
 158         va_start(params, format);
 159         vsnprintf(buf, sizeof(buf), format, params);
 160         va_end(params);
 161         die("pack has bad object at offset %lu: %s", offset, buf);
 162 }
 163
 164 static void *unpack_entry_data(unsigned long offset, unsigned long size)
 165 {
 166         z_stream stream;
 167         void *buf = xmalloc(size);
 168
 169         memset(&stream, 0, sizeof(stream));
 170         stream.next_out = buf;
 171         stream.avail_out = size;
 172         stream.next_in = fill(1);
 173         stream.avail_in = input_len;
 174         inflateInit(&stream);
 175
 176         for (;;) {
 177                 int ret = inflate(&stream, 0);
 178                 use(input_len - stream.avail_in);
 179                 if (stream.total_out == size && ret == Z_STREAM_END)
 180                         break;
 181                 if (ret != Z_OK)
 182                         bad_object(offset, "inflate returned %d", ret);
 183                 stream.next_in = fill(1);
 184                 stream.avail_in = input_len;
 185         }
 186         inflateEnd(&stream);
 187         return buf;
 188 }
 189
 190 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 191 {
 192         unsigned char *p, c;
 193         unsigned long size;
 194         off_t base_offset;
 195         unsigned shift;
 196         void *data;
 197
 198         obj->idx.offset = consumed_bytes;
 199         input_crc32 = crc32(0, Z_NULL, 0);
 200
 201         p = fill(1);
 202         c = *p;
 203         use(1);
 204         obj->type = (c >> 4) & 7;
 205         size = (c & 15);
 206         shift = 4;
 207         while (c & 0x80) {
 208                 p = fill(1);
 209                 c = *p;
 210                 use(1);
 211                 size += (c & 0x7fUL) << shift;
 212                 shift += 7;
 213         }
 214         obj->size = size;
 215
 216         switch (obj->type) {
 217         case OBJ_REF_DELTA:
 218                 hashcpy(delta_base->sha1, fill(20));
 219                 use(20);
 220                 break;
 221         case OBJ_OFS_DELTA:
 222                 memset(delta_base, 0, sizeof(*delta_base));
 223                 p = fill(1);
 224                 c = *p;
 225                 use(1);
 226                 base_offset = c & 127;
 227                 while (c & 128) {
 228                         base_offset += 1;
 229                         if (!base_offset || MSB(base_offset, 7))
 230                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
 231                         p = fill(1);
 232                         c = *p;
 233                         use(1);
 234                         base_offset = (base_offset << 7) + (c & 127);
 235                 }
 236                 delta_base->offset = obj->idx.offset - base_offset;
 237                 if (delta_base->offset >= obj->idx.offset)
 238                         bad_object(obj->idx.offset, "delta base offset is out of bound");
 239                 break;
 240         case OBJ_COMMIT:
 241         case OBJ_TREE:
 242         case OBJ_BLOB:
 243         case OBJ_TAG:
 244                 break;
 245         default:
 246                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 247         }
 248         obj->hdr_size = consumed_bytes - obj->idx.offset;
 249
 250         data = unpack_entry_data(obj->idx.offset, obj->size);
 251         obj->idx.crc32 = input_crc32;
 252         return data;
 253 }
 254
 255 static void *get_data_from_pack(struct object_entry *obj)
 256 {
 257         unsigned long from = obj[0].idx.offset + obj[0].hdr_size;
 258         unsigned long len = obj[1].idx.offset - from;
 259         unsigned long rdy = 0;
 260         unsigned char *src, *data;
 261         z_stream stream;
 262         int st;
 263
 264         src = xmalloc(len);
 265         data = src;
 266         do {
 267                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
 268                 if (n <= 0)
 269                         die("cannot pread pack file: %s", strerror(errno));
 270                 rdy += n;
 271         } while (rdy < len);
 272         data = xmalloc(obj->size);
 273         memset(&stream, 0, sizeof(stream));
 274         stream.next_out = data;
 275         stream.avail_out = obj->size;
 276         stream.next_in = src;
 277         stream.avail_in = len;
 278         inflateInit(&stream);
 279         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
 280         inflateEnd(&stream);
 281         if (st != Z_STREAM_END || stream.total_out != obj->size)
 282                 die("serious inflate inconsistency");
 283         free(src);
 284         return data;
 285 }
 286
 287 static int find_delta(const union delta_base *base)
 288 {
 289         int first = 0, last = nr_deltas;
 290
 291         while (first < last) {
 292                 int next = (first + last) / 2;
 293                 struct delta_entry *delta = &deltas[next];
 294                 int cmp;
 295
 296                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 297                 if (!cmp)
 298                         return next;
 299                 if (cmp < 0) {
 300                         last = next;
 301                         continue;
 302                 }
 303                 first = next+1;
 304         }
 305         return -first-1;
 306 }
 307
 308 static int find_delta_children(const union delta_base *base,
 309                                int *first_index, int *last_index)
 310 {
 311         int first = find_delta(base);
 312         int last = first;
 313         int end = nr_deltas - 1;
 314
 315         if (first < 0)
 316                 return -1;
 317         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 318                 --first;
 319         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 320                 ++last;
 321         *first_index = first;
 322         *last_index = last;
 323         return 0;
 324 }
 325
 326 static void sha1_object(const void *data, unsigned long size,
 327                         enum object_type type, unsigned char *sha1)
 328 {
 329         hash_sha1_file(data, size, typename(type), sha1);
 330         if (has_sha1_file(sha1)) {
 331                 void *has_data;
 332                 enum object_type has_type;
 333                 unsigned long has_size;
 334                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 335                 if (!has_data)
 336                         die("cannot read existing object %s", sha1_to_hex(sha1));
 337                 if (size != has_size || type != has_type ||
 338                     memcmp(data, has_data, size) != 0)
 339                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 340                 free(has_data);
 341         }
 342 }
 343
 344 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
 345                           unsigned long base_size, enum object_type type)
 346 {
 347         void *delta_data;
 348         unsigned long delta_size;
 349         void *result;
 350         unsigned long result_size;
 351         union delta_base delta_base;
 352         int j, first, last;
 353
 354         delta_obj->real_type = type;
 355         delta_data = get_data_from_pack(delta_obj);
 356         delta_size = delta_obj->size;
 357         result = patch_delta(base_data, base_size, delta_data, delta_size,
 358                              &result_size);
 359         free(delta_data);
 360         if (!result)
 361                 bad_object(delta_obj->idx.offset, "failed to apply delta");
 362         sha1_object(result, result_size, type, delta_obj->idx.sha1);
 363         nr_resolved_deltas++;
 364
 365         hashcpy(delta_base.sha1, delta_obj->idx.sha1);
 366         if (!find_delta_children(&delta_base, &first, &last)) {
 367                 for (j = first; j <= last; j++) {
 368                         struct object_entry *child = objects + deltas[j].obj_no;
 369                         if (child->real_type == OBJ_REF_DELTA)
 370                                 resolve_delta(child, result, result_size, type);
 371                 }
 372         }
 373
 374         memset(&delta_base, 0, sizeof(delta_base));
 375         delta_base.offset = delta_obj->idx.offset;
 376         if (!find_delta_children(&delta_base, &first, &last)) {
 377                 for (j = first; j <= last; j++) {
 378                         struct object_entry *child = objects + deltas[j].obj_no;
 379                         if (child->real_type == OBJ_OFS_DELTA)
 380                                 resolve_delta(child, result, result_size, type);
 381                 }
 382         }
 383
 384         free(result);
 385 }
 386
 387 static int compare_delta_entry(const void *a, const void *b)
 388 {
 389         const struct delta_entry *delta_a = a;
 390         const struct delta_entry *delta_b = b;
 391         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 392 }
 393
 394 /* Parse all objects and return the pack content SHA1 hash */
 395 static void parse_pack_objects(unsigned char *sha1)
 396 {
 397         int i;
 398         struct delta_entry *delta = deltas;
 399         void *data;
 400         struct stat st;
 401
 402         /*
 403          * First pass:
 404          * - find locations of all objects;
 405          * - calculate SHA1 of all non-delta objects;
 406          * - remember base (SHA1 or offset) for all deltas.
 407          */
 408         if (verbose)
 409                 start_progress(&progress, "Indexing %u objects...", "", nr_objects);
 410         for (i = 0; i < nr_objects; i++) {
 411                 struct object_entry *obj = &objects[i];
 412                 data = unpack_raw_entry(obj, &delta->base);
 413                 obj->real_type = obj->type;
 414                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 415                         nr_deltas++;
 416                         delta->obj_no = i;
 417                         delta++;
 418                 } else
 419                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 420                 free(data);
 421                 if (verbose)
 422                         display_progress(&progress, i+1);
 423         }
 424         objects[i].idx.offset = consumed_bytes;
 425         if (verbose)
 426                 stop_progress(&progress);
 427
 428         /* Check pack integrity */
 429         flush();
 430         SHA1_Final(sha1, &input_ctx);
 431         if (hashcmp(fill(20), sha1))
 432                 die("pack is corrupted (SHA1 mismatch)");
 433         use(20);
 434
 435         /* If input_fd is a file, we should have reached its end now. */
 436         if (fstat(input_fd, &st))
 437                 die("cannot fstat packfile: %s", strerror(errno));
 438         if (S_ISREG(st.st_mode) &&
 439                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 440                 die("pack has junk at the end");
 441
 442         if (!nr_deltas)
 443                 return;
 444
 445         /* Sort deltas by base SHA1/offset for fast searching */
 446         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 447               compare_delta_entry);
 448
 449         /*
 450          * Second pass:
 451          * - for all non-delta objects, look if it is used as a base for
 452          *   deltas;
 453          * - if used as a base, uncompress the object and apply all deltas,
 454          *   recursively checking if the resulting object is used as a base
 455          *   for some more deltas.
 456          */
 457         if (verbose)
 458                 start_progress(&progress, "Resolving %u deltas...", "", nr_deltas);
 459         for (i = 0; i < nr_objects; i++) {
 460                 struct object_entry *obj = &objects[i];
 461                 union delta_base base;
 462                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
 463
 464                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 465                         continue;
 466                 hashcpy(base.sha1, obj->idx.sha1);
 467                 ref = !find_delta_children(&base, &ref_first, &ref_last);
 468                 memset(&base, 0, sizeof(base));
 469                 base.offset = obj->idx.offset;
 470                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
 471                 if (!ref && !ofs)
 472                         continue;
 473                 data = get_data_from_pack(obj);
 474                 if (ref)
 475                         for (j = ref_first; j <= ref_last; j++) {
 476                                 struct object_entry *child = objects + deltas[j].obj_no;
 477                                 if (child->real_type == OBJ_REF_DELTA)
 478                                         resolve_delta(child, data,
 479                                                       obj->size, obj->type);
 480                         }
 481                 if (ofs)
 482                         for (j = ofs_first; j <= ofs_last; j++) {
 483                                 struct object_entry *child = objects + deltas[j].obj_no;
 484                                 if (child->real_type == OBJ_OFS_DELTA)
 485                                         resolve_delta(child, data,
 486                                                       obj->size, obj->type);
 487                         }
 488                 free(data);
 489                 if (verbose)
 490                         display_progress(&progress, nr_resolved_deltas);
 491         }
 492 }
 493
 494 static int write_compressed(int fd, void *in, unsigned int size, uint32_t *obj_crc)
 495 {
 496         z_stream stream;
 497         unsigned long maxsize;
 498         void *out;
 499
 500         memset(&stream, 0, sizeof(stream));
 501         deflateInit(&stream, zlib_compression_level);
 502         maxsize = deflateBound(&stream, size);
 503         out = xmalloc(maxsize);
 504
 505         /* Compress it */
 506         stream.next_in = in;
 507         stream.avail_in = size;
 508         stream.next_out = out;
 509         stream.avail_out = maxsize;
 510         while (deflate(&stream, Z_FINISH) == Z_OK);
 511         deflateEnd(&stream);
 512
 513         size = stream.total_out;
 514         write_or_die(fd, out, size);
 515         *obj_crc = crc32(*obj_crc, out, size);
 516         free(out);
 517         return size;
 518 }
 519
 520 static void append_obj_to_pack(const unsigned char *sha1, void *buf,
 521                                unsigned long size, enum object_type type)
 522 {
 523         struct object_entry *obj = &objects[nr_objects++];
 524         unsigned char header[10];
 525         unsigned long s = size;
 526         int n = 0;
 527         unsigned char c = (type << 4) | (s & 15);
 528         s >>= 4;
 529         while (s) {
 530                 header[n++] = c | 0x80;
 531                 c = s & 0x7f;
 532                 s >>= 7;
 533         }
 534         header[n++] = c;
 535         write_or_die(output_fd, header, n);
 536         obj[0].idx.crc32 = crc32(0, Z_NULL, 0);
 537         obj[0].idx.crc32 = crc32(obj[0].idx.crc32, header, n);
 538         obj[1].idx.offset = obj[0].idx.offset + n;
 539         obj[1].idx.offset += write_compressed(output_fd, buf, size, &obj[0].idx.crc32);
 540         hashcpy(obj->idx.sha1, sha1);
 541 }
 542
 543 static int delta_pos_compare(const void *_a, const void *_b)
 544 {
 545         struct delta_entry *a = *(struct delta_entry **)_a;
 546         struct delta_entry *b = *(struct delta_entry **)_b;
 547         return a->obj_no - b->obj_no;
 548 }
 549
 550 static void fix_unresolved_deltas(int nr_unresolved)
 551 {
 552         struct delta_entry **sorted_by_pos;
 553         int i, n = 0;
 554
 555         /*
 556          * Since many unresolved deltas may well be themselves base objects
 557          * for more unresolved deltas, we really want to include the
 558          * smallest number of base objects that would cover as much delta
 559          * as possible by picking the
 560          * trunc deltas first, allowing for other deltas to resolve without
 561          * additional base objects.  Since most base objects are to be found
 562          * before deltas depending on them, a good heuristic is to start
 563          * resolving deltas in the same order as their position in the pack.
 564          */
 565         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 566         for (i = 0; i < nr_deltas; i++) {
 567                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 568                         continue;
 569                 sorted_by_pos[n++] = &deltas[i];
 570         }
 571         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 572
 573         for (i = 0; i < n; i++) {
 574                 struct delta_entry *d = sorted_by_pos[i];
 575                 void *data;
 576                 unsigned long size;
 577                 enum object_type type;
 578                 int j, first, last;
 579
 580                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 581                         continue;
 582                 data = read_sha1_file(d->base.sha1, &type, &size);
 583                 if (!data)
 584                         continue;
 585
 586                 find_delta_children(&d->base, &first, &last);
 587                 for (j = first; j <= last; j++) {
 588                         struct object_entry *child = objects + deltas[j].obj_no;
 589                         if (child->real_type == OBJ_REF_DELTA)
 590                                 resolve_delta(child, data, size, type);
 591                 }
 592
 593                 if (check_sha1_signature(d->base.sha1, data, size, typename(type)))
 594                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 595                 append_obj_to_pack(d->base.sha1, data, size, type);
 596                 free(data);
 597                 if (verbose)
 598                         display_progress(&progress, nr_resolved_deltas);
 599         }
 600         free(sorted_by_pos);
 601 }
 602
 603 static void final(const char *final_pack_name, const char *curr_pack_name,
 604                   const char *final_index_name, const char *curr_index_name,
 605                   const char *keep_name, const char *keep_msg,
 606                   unsigned char *sha1)
 607 {
 608         const char *report = "pack";
 609         char name[PATH_MAX];
 610         int err;
 611
 612         if (!from_stdin) {
 613                 close(input_fd);
 614         } else {
 615                 err = close(output_fd);
 616                 if (err)
 617                         die("error while closing pack file: %s", strerror(errno));
 618                 chmod(curr_pack_name, 0444);
 619         }
 620
 621         if (keep_msg) {
 622                 int keep_fd, keep_msg_len = strlen(keep_msg);
 623                 if (!keep_name) {
 624                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
 625                                  get_object_directory(), sha1_to_hex(sha1));
 626                         keep_name = name;
 627                 }
 628                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 629                 if (keep_fd < 0) {
 630                         if (errno != EEXIST)
 631                                 die("cannot write keep file");
 632                 } else {
 633                         if (keep_msg_len > 0) {
 634                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
 635                                 write_or_die(keep_fd, "\n", 1);
 636                         }
 637                         if (close(keep_fd) != 0)
 638                                 die("cannot write keep file");
 639                         report = "keep";
 640                 }
 641         }
 642
 643         if (final_pack_name != curr_pack_name) {
 644                 if (!final_pack_name) {
 645                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 646                                  get_object_directory(), sha1_to_hex(sha1));
 647                         final_pack_name = name;
 648                 }
 649                 if (move_temp_to_file(curr_pack_name, final_pack_name))
 650                         die("cannot store pack file");
 651         }
 652
 653         chmod(curr_index_name, 0444);
 654         if (final_index_name != curr_index_name) {
 655                 if (!final_index_name) {
 656                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 657                                  get_object_directory(), sha1_to_hex(sha1));
 658                         final_index_name = name;
 659                 }
 660                 if (move_temp_to_file(curr_index_name, final_index_name))
 661                         die("cannot store index file");
 662         }
 663
 664         if (!from_stdin) {
 665                 printf("%s\n", sha1_to_hex(sha1));
 666         } else {
 667                 char buf[48];
 668                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 669                                    report, sha1_to_hex(sha1));
 670                 write_or_die(1, buf, len);
 671
 672                 /*
 673                  * Let's just mimic git-unpack-objects here and write
 674                  * the last part of the input buffer to stdout.
 675                  */
 676                 while (input_len) {
 677                         err = xwrite(1, input_buffer + input_offset, input_len);
 678                         if (err <= 0)
 679                                 break;
 680                         input_len -= err;
 681                         input_offset += err;
 682                 }
 683         }
 684 }
 685
 686 int main(int argc, char **argv)
 687 {
 688         int i, fix_thin_pack = 0;
 689         const char *curr_pack, *pack_name = NULL;
 690         const char *curr_index, *index_name = NULL;
 691         const char *keep_name = NULL, *keep_msg = NULL;
 692         char *index_name_buf = NULL, *keep_name_buf = NULL;
 693         struct pack_idx_entry **idx_objects;
 694         unsigned char sha1[20];
 695
 696         for (i = 1; i < argc; i++) {
 697                 const char *arg = argv[i];
 698
 699                 if (*arg == '-') {
 700                         if (!strcmp(arg, "--stdin")) {
 701                                 from_stdin = 1;
 702                         } else if (!strcmp(arg, "--fix-thin")) {
 703                                 fix_thin_pack = 1;
 704                         } else if (!strcmp(arg, "--keep")) {
 705                                 keep_msg = "";
 706                         } else if (!prefixcmp(arg, "--keep=")) {
 707                                 keep_msg = arg + 7;
 708                         } else if (!prefixcmp(arg, "--pack_header=")) {
 709                                 struct pack_header *hdr;
 710                                 char *c;
 711
 712                                 hdr = (struct pack_header *)input_buffer;
 713                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
 714                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 715                                 if (*c != ',')
 716                                         die("bad %s", arg);
 717                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 718                                 if (*c)
 719                                         die("bad %s", arg);
 720                                 input_len = sizeof(*hdr);
 721                         } else if (!strcmp(arg, "-v")) {
 722                                 verbose = 1;
 723                         } else if (!strcmp(arg, "-o")) {
 724                                 if (index_name || (i+1) >= argc)
 725                                         usage(index_pack_usage);
 726                                 index_name = argv[++i];
 727                         } else if (!prefixcmp(arg, "--index-version=")) {
 728                                 char *c;
 729                                 pack_idx_default_version = strtoul(arg + 16, &c, 10);
 730                                 if (pack_idx_default_version > 2)
 731                                         die("bad %s", arg);
 732                                 if (*c == ',')
 733                                         pack_idx_off32_limit = strtoul(c+1, &c, 0);
 734                                 if (*c || pack_idx_off32_limit & 0x80000000)
 735                                         die("bad %s", arg);
 736                         } else
 737                                 usage(index_pack_usage);
 738                         continue;
 739                 }
 740
 741                 if (pack_name)
 742                         usage(index_pack_usage);
 743                 pack_name = arg;
 744         }
 745
 746         if (!pack_name && !from_stdin)
 747                 usage(index_pack_usage);
 748         if (fix_thin_pack && !from_stdin)
 749                 die("--fix-thin cannot be used without --stdin");
 750         if (!index_name && pack_name) {
 751                 int len = strlen(pack_name);
 752                 if (!has_extension(pack_name, ".pack"))
 753                         die("packfile name '%s' does not end with '.pack'",
 754                             pack_name);
 755                 index_name_buf = xmalloc(len);
 756                 memcpy(index_name_buf, pack_name, len - 5);
 757                 strcpy(index_name_buf + len - 5, ".idx");
 758                 index_name = index_name_buf;
 759         }
 760         if (keep_msg && !keep_name && pack_name) {
 761                 int len = strlen(pack_name);
 762                 if (!has_extension(pack_name, ".pack"))
 763                         die("packfile name '%s' does not end with '.pack'",
 764                             pack_name);
 765                 keep_name_buf = xmalloc(len);
 766                 memcpy(keep_name_buf, pack_name, len - 5);
 767                 strcpy(keep_name_buf + len - 5, ".keep");
 768                 keep_name = keep_name_buf;
 769         }
 770
 771         curr_pack = open_pack_file(pack_name);
 772         parse_pack_header();
 773         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 774         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 775         parse_pack_objects(sha1);
 776         if (nr_deltas == nr_resolved_deltas) {
 777                 if (verbose)
 778                         stop_progress(&progress);
 779                 /* Flush remaining pack final 20-byte SHA1. */
 780                 flush();
 781         } else {
 782                 if (fix_thin_pack) {
 783                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
 784                         int nr_objects_initial = nr_objects;
 785                         if (nr_unresolved <= 0)
 786                                 die("confusion beyond insanity");
 787                         objects = xrealloc(objects,
 788                                            (nr_objects + nr_unresolved + 1)
 789                                            * sizeof(*objects));
 790                         fix_unresolved_deltas(nr_unresolved);
 791                         if (verbose) {
 792                                 stop_progress(&progress);
 793                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
 794                                         nr_objects - nr_objects_initial);
 795                         }
 796                         fixup_pack_header_footer(output_fd, sha1,
 797                                 curr_pack, nr_objects);
 798                 }
 799                 if (nr_deltas != nr_resolved_deltas)
 800                         die("pack has %d unresolved deltas",
 801                             nr_deltas - nr_resolved_deltas);
 802         }
 803         free(deltas);
 804
 805         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
 806         for (i = 0; i < nr_objects; i++)
 807                 idx_objects[i] = &objects[i].idx;
 808         curr_index = write_idx_file(index_name, idx_objects, nr_objects, sha1);
 809         free(idx_objects);
 810
 811         final(pack_name, curr_pack,
 812                 index_name, curr_index,
 813                 keep_name, keep_msg,
 814                 sha1);
 815         free(objects);
 816         free(index_name_buf);
 817         free(keep_name_buf);
 818
 819         return 0;
 820 }