sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include "cache.h"
  10 #include "delta.h"
  11
  12 #ifndef O_NOATIME
  13 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  14 #define O_NOATIME 01000000
  15 #else
  16 #define O_NOATIME 0
  17 #endif
  18 #endif
  19
  20 static unsigned int sha1_file_open_flag = O_NOATIME;
  21
  22 static unsigned hexval(char c)
  23 {
  24         if (c >= '0' && c <= '9')
  25                 return c - '0';
  26         if (c >= 'a' && c <= 'f')
  27                 return c - 'a' + 10;
  28         if (c >= 'A' && c <= 'F')
  29                 return c - 'A' + 10;
  30         return ~0;
  31 }
  32
  33 int get_sha1_hex(const char *hex, unsigned char *sha1)
  34 {
  35         int i;
  36         for (i = 0; i < 20; i++) {
  37                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  38                 if (val & ~0xff)
  39                         return -1;
  40                 *sha1++ = val;
  41                 hex += 2;
  42         }
  43         return 0;
  44 }
  45
  46 static int get_sha1_file(const char *path, unsigned char *result)
  47 {
  48         char buffer[60];
  49         int fd = open(path, O_RDONLY);
  50         int len;
  51
  52         if (fd < 0)
  53                 return -1;
  54         len = read(fd, buffer, sizeof(buffer));
  55         close(fd);
  56         if (len < 40)
  57                 return -1;
  58         return get_sha1_hex(buffer, result);
  59 }
  60
  61 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
  62 static void setup_git_env(void)
  63 {
  64         git_dir = gitenv(GIT_DIR_ENVIRONMENT);
  65         if (!git_dir)
  66                 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
  67         git_object_dir = gitenv(DB_ENVIRONMENT);
  68         if (!git_object_dir) {
  69                 git_object_dir = xmalloc(strlen(git_dir) + 9);
  70                 sprintf(git_object_dir, "%s/objects", git_dir);
  71         }
  72         git_refs_dir = xmalloc(strlen(git_dir) + 6);
  73         sprintf(git_refs_dir, "%s/refs", git_dir);
  74         git_index_file = gitenv(INDEX_ENVIRONMENT);
  75         if (!git_index_file) {
  76                 git_index_file = xmalloc(strlen(git_dir) + 7);
  77                 sprintf(git_index_file, "%s/index", git_dir);
  78         }
  79 }
  80
  81 char *get_object_directory(void)
  82 {
  83         if (!git_object_dir)
  84                 setup_git_env();
  85         return git_object_dir;
  86 }
  87
  88 char *get_refs_directory(void)
  89 {
  90         if (!git_refs_dir)
  91                 setup_git_env();
  92         return git_refs_dir;
  93 }
  94
  95 char *get_index_file(void)
  96 {
  97         if (!git_index_file)
  98                 setup_git_env();
  99         return git_index_file;
 100 }
 101
 102 int get_sha1(const char *str, unsigned char *sha1)
 103 {
 104         static char pathname[PATH_MAX];
 105         static const char *prefix[] = {
 106                 "",
 107                 "refs",
 108                 "refs/tags",
 109                 "refs/heads",
 110                 "refs/snap",
 111                 NULL
 112         };
 113         const char **p;
 114
 115         if (!get_sha1_hex(str, sha1))
 116                 return 0;
 117
 118         if (!git_dir)
 119                 setup_git_env();
 120         for (p = prefix; *p; p++) {
 121                 snprintf(pathname, sizeof(pathname), "%s/%s/%s",
 122                          git_dir, *p, str);
 123                 if (!get_sha1_file(pathname, sha1))
 124                         return 0;
 125         }
 126
 127         return -1;
 128 }
 129
 130 char * sha1_to_hex(const unsigned char *sha1)
 131 {
 132         static char buffer[50];
 133         static const char hex[] = "0123456789abcdef";
 134         char *buf = buffer;
 135         int i;
 136
 137         for (i = 0; i < 20; i++) {
 138                 unsigned int val = *sha1++;
 139                 *buf++ = hex[val >> 4];
 140                 *buf++ = hex[val & 0xf];
 141         }
 142         return buffer;
 143 }
 144
 145 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 146 {
 147         int i;
 148         for (i = 0; i < 20; i++) {
 149                 static char hex[] = "0123456789abcdef";
 150                 unsigned int val = sha1[i];
 151                 char *pos = pathbuf + i*2 + (i > 0);
 152                 *pos++ = hex[val >> 4];
 153                 *pos = hex[val & 0xf];
 154         }
 155 }
 156
 157 /*
 158  * NOTE! This returns a statically allocated buffer, so you have to be
 159  * careful about using it. Do a "strdup()" if you need to save the
 160  * filename.
 161  *
 162  * Also note that this returns the location for creating.  Reading
 163  * SHA1 file can happen from any alternate directory listed in the
 164  * DB_ENVIRONMENT environment variable if it is not found in
 165  * the primary object database.
 166  */
 167 char *sha1_file_name(const unsigned char *sha1)
 168 {
 169         static char *name, *base;
 170
 171         if (!base) {
 172                 const char *sha1_file_directory = get_object_directory();
 173                 int len = strlen(sha1_file_directory);
 174                 base = xmalloc(len + 60);
 175                 memcpy(base, sha1_file_directory, len);
 176                 memset(base+len, 0, 60);
 177                 base[len] = '/';
 178                 base[len+3] = '/';
 179                 name = base + len + 1;
 180         }
 181         fill_sha1_path(name, sha1);
 182         return base;
 183 }
 184
 185 static struct alternate_object_database {
 186         char *base;
 187         char *name;
 188 } *alt_odb;
 189
 190 /*
 191  * Prepare alternate object database registry.
 192  * alt_odb points at an array of struct alternate_object_database.
 193  * This array is terminated with an element that has both its base
 194  * and name set to NULL.  alt_odb[n] comes from n'th non-empty
 195  * element from colon separated ALTERNATE_DB_ENVIRONMENT environment
 196  * variable, and its base points at a statically allocated buffer
 197  * that contains "/the/directory/corresponding/to/.git/objects/...",
 198  * while its name points just after the slash at the end of
 199  * ".git/objects/" in the example above, and has enough space to hold
 200  * 40-byte hex SHA1, an extra slash for the first level indirection,
 201  * and the terminating NUL.
 202  * This function allocates the alt_odb array and all the strings
 203  * pointed by base fields of the array elements with one xmalloc();
 204  * the string pool immediately follows the array.
 205  */
 206 static void prepare_alt_odb(void)
 207 {
 208         int pass, totlen, i;
 209         const char *cp, *last;
 210         char *op = NULL;
 211         const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
 212
 213         /* The first pass counts how large an area to allocate to
 214          * hold the entire alt_odb structure, including array of
 215          * structs and path buffers for them.  The second pass fills
 216          * the structure and prepares the path buffers for use by
 217          * fill_sha1_path().
 218          */
 219         for (totlen = pass = 0; pass < 2; pass++) {
 220                 last = alt;
 221                 i = 0;
 222                 do {
 223                         cp = strchr(last, ':') ? : last + strlen(last);
 224                         if (last != cp) {
 225                                 /* 43 = 40-byte + 2 '/' + terminating NUL */
 226                                 int pfxlen = cp - last;
 227                                 int entlen = pfxlen + 43;
 228                                 if (pass == 0)
 229                                         totlen += entlen;
 230                                 else {
 231                                         alt_odb[i].base = op;
 232                                         alt_odb[i].name = op + pfxlen + 1;
 233                                         memcpy(op, last, pfxlen);
 234                                         op[pfxlen] = op[pfxlen + 3] = '/';
 235                                         op[entlen-1] = 0;
 236                                         op += entlen;
 237                                 }
 238                                 i++;
 239                         }
 240                         while (*cp && *cp == ':')
 241                                 cp++;
 242                         last = cp;
 243                 } while (*cp);
 244                 if (pass)
 245                         break;
 246                 alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
 247                 alt_odb[i].base = alt_odb[i].name = NULL;
 248                 op = (char*)(&alt_odb[i+1]);
 249         }
 250 }
 251
 252 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 253 {
 254         int i;
 255         char *name = sha1_file_name(sha1);
 256
 257         if (!stat(name, st))
 258                 return name;
 259         if (!alt_odb)
 260                 prepare_alt_odb();
 261         for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
 262                 fill_sha1_path(name, sha1);
 263                 if (!stat(alt_odb[i].base, st))
 264                         return alt_odb[i].base;
 265         }
 266         return NULL;
 267 }
 268
 269 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 270 {
 271         char header[100];
 272         unsigned char real_sha1[20];
 273         SHA_CTX c;
 274
 275         SHA1_Init(&c);
 276         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 277         SHA1_Update(&c, map, size);
 278         SHA1_Final(real_sha1, &c);
 279         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 280 }
 281
 282 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 283 {
 284         struct stat st;
 285         void *map;
 286         int fd;
 287         char *filename = find_sha1_file(sha1, &st);
 288
 289         if (!filename) {
 290                 error("cannot map sha1 file %s", sha1_to_hex(sha1));
 291                 return NULL;
 292         }
 293
 294         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 295         if (fd < 0) {
 296                 /* See if it works without O_NOATIME */
 297                 switch (sha1_file_open_flag) {
 298                 default:
 299                         fd = open(filename, O_RDONLY);
 300                         if (fd >= 0)
 301                                 break;
 302                 /* Fallthrough */
 303                 case 0:
 304                         perror(filename);
 305                         return NULL;
 306                 }
 307
 308                 /* If it failed once, it will probably fail again. Stop using O_NOATIME */
 309                 sha1_file_open_flag = 0;
 310         }
 311         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 312         close(fd);
 313         if (-1 == (int)(long)map)
 314                 return NULL;
 315         *size = st.st_size;
 316         return map;
 317 }
 318
 319 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 320 {
 321         /* Get the data stream */
 322         memset(stream, 0, sizeof(*stream));
 323         stream->next_in = map;
 324         stream->avail_in = mapsize;
 325         stream->next_out = buffer;
 326         stream->avail_out = size;
 327
 328         inflateInit(stream);
 329         return inflate(stream, 0);
 330 }
 331
 332 void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 333 {
 334         int bytes = strlen(buffer) + 1;
 335         unsigned char *buf = xmalloc(1+size);
 336
 337         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 338         bytes = stream->total_out - bytes;
 339         if (bytes < size) {
 340                 stream->next_out = buf + bytes;
 341                 stream->avail_out = size - bytes;
 342                 while (inflate(stream, Z_FINISH) == Z_OK)
 343                         /* nothing */;
 344         }
 345         buf[size] = 0;
 346         inflateEnd(stream);
 347         return buf;
 348 }
 349
 350 /*
 351  * We used to just use "sscanf()", but that's actually way
 352  * too permissive for what we want to check. So do an anal
 353  * object header parse by hand.
 354  */
 355 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 356 {
 357         int i;
 358         unsigned long size;
 359
 360         /*
 361          * The type can be at most ten bytes (including the
 362          * terminating '\0' that we add), and is followed by
 363          * a space.
 364          */
 365         i = 10;
 366         for (;;) {
 367                 char c = *hdr++;
 368                 if (c == ' ')
 369                         break;
 370                 if (!--i)
 371                         return -1;
 372                 *type++ = c;
 373         }
 374         *type = 0;
 375
 376         /*
 377          * The length must follow immediately, and be in canonical
 378          * decimal format (ie "010" is not valid).
 379          */
 380         size = *hdr++ - '0';
 381         if (size > 9)
 382                 return -1;
 383         if (size) {
 384                 for (;;) {
 385                         unsigned long c = *hdr - '0';
 386                         if (c > 9)
 387                                 break;
 388                         hdr++;
 389                         size = size * 10 + c;
 390                 }
 391         }
 392         *sizep = size;
 393
 394         /*
 395          * The length must be followed by a zero byte
 396          */
 397         return *hdr ? -1 : 0;
 398 }
 399
 400 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 401 {
 402         int ret;
 403         z_stream stream;
 404         char hdr[8192];
 405
 406         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 407         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 408                 return NULL;
 409
 410         return unpack_sha1_rest(&stream, hdr, *size);
 411 }
 412
 413 int sha1_delta_base(const unsigned char *sha1, unsigned char *base_sha1)
 414 {
 415         int ret;
 416         unsigned long mapsize, size;
 417         void *map;
 418         z_stream stream;
 419         char hdr[64], type[20];
 420         void *delta_data_head;
 421
 422         map = map_sha1_file(sha1, &mapsize);
 423         if (!map)
 424                 return -1;
 425         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 426         if (ret < Z_OK || parse_sha1_header(hdr, type, &size) < 0) {
 427                 ret = -1;
 428                 goto out;
 429         }
 430         if (strcmp(type, "delta")) {
 431                 ret = 0;
 432                 goto out;
 433         }
 434
 435         delta_data_head = hdr + strlen(hdr) + 1;
 436         ret = 1;
 437         memcpy(base_sha1, delta_data_head, 20);
 438  out:
 439         inflateEnd(&stream);
 440         munmap(map, mapsize);
 441         return ret;
 442 }
 443
 444 int sha1_file_size(const unsigned char *sha1, unsigned long *sizep)
 445 {
 446         int ret, status;
 447         unsigned long mapsize, size;
 448         void *map;
 449         z_stream stream;
 450         char hdr[64], type[20];
 451         const unsigned char *data;
 452         unsigned char cmd;
 453         int i;
 454
 455         map = map_sha1_file(sha1, &mapsize);
 456         if (!map)
 457                 return -1;
 458         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 459         status = -1;
 460         if (ret < Z_OK || parse_sha1_header(hdr, type, &size) < 0)
 461                 goto out;
 462         if (strcmp(type, "delta")) {
 463                 *sizep = size;
 464                 status = 0;
 465                 goto out;
 466         }
 467
 468         /* We are dealing with a delta object.  Inflated, the first
 469          * 20 bytes hold the base object SHA1, and delta data follows
 470          * immediately after it.
 471          *
 472          * The initial part of the delta starts at delta_data_head +
 473          * 20.  Borrow code from patch-delta to read the result size.
 474          */
 475         data = (unsigned char *)(hdr + strlen(hdr) + 1 + 20);
 476
 477         /* Skip over the source size; we are not interested in
 478          * it and we cannot verify it because we do not want
 479          * to read the base object.
 480          */
 481         cmd = *data++;
 482         while (cmd) {
 483                 if (cmd & 1)
 484                         data++;
 485                 cmd >>= 1;
 486         }
 487         /* Read the result size */
 488         size = i = 0;
 489         cmd = *data++;
 490         while (cmd) {
 491                 if (cmd & 1)
 492                         size |= *data++ << i;
 493                 i += 8;
 494                 cmd >>= 1;
 495         }
 496         *sizep = size;
 497         status = 0;
 498  out:
 499         inflateEnd(&stream);
 500         munmap(map, mapsize);
 501         return status;
 502 }
 503
 504 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 505 {
 506         unsigned long mapsize;
 507         void *map, *buf;
 508
 509         map = map_sha1_file(sha1, &mapsize);
 510         if (map) {
 511                 buf = unpack_sha1_file(map, mapsize, type, size);
 512                 munmap(map, mapsize);
 513                 if (buf && !strcmp(type, "delta")) {
 514                         void *ref = NULL, *delta = buf;
 515                         unsigned long ref_size, delta_size = *size;
 516                         buf = NULL;
 517                         if (delta_size > 20)
 518                                 ref = read_sha1_file(delta, type, &ref_size);
 519                         if (ref)
 520                                 buf = patch_delta(ref, ref_size,
 521                                                   delta+20, delta_size-20,
 522                                                   size);
 523                         free(delta);
 524                         free(ref);
 525                 }
 526                 return buf;
 527         }
 528         return NULL;
 529 }
 530
 531 void *read_object_with_reference(const unsigned char *sha1,
 532                                  const char *required_type,
 533                                  unsigned long *size,
 534                                  unsigned char *actual_sha1_return)
 535 {
 536         char type[20];
 537         void *buffer;
 538         unsigned long isize;
 539         unsigned char actual_sha1[20];
 540
 541         memcpy(actual_sha1, sha1, 20);
 542         while (1) {
 543                 int ref_length = -1;
 544                 const char *ref_type = NULL;
 545
 546                 buffer = read_sha1_file(actual_sha1, type, &isize);
 547                 if (!buffer)
 548                         return NULL;
 549                 if (!strcmp(type, required_type)) {
 550                         *size = isize;
 551                         if (actual_sha1_return)
 552                                 memcpy(actual_sha1_return, actual_sha1, 20);
 553                         return buffer;
 554                 }
 555                 /* Handle references */
 556                 else if (!strcmp(type, "commit"))
 557                         ref_type = "tree ";
 558                 else if (!strcmp(type, "tag"))
 559                         ref_type = "object ";
 560                 else {
 561                         free(buffer);
 562                         return NULL;
 563                 }
 564                 ref_length = strlen(ref_type);
 565
 566                 if (memcmp(buffer, ref_type, ref_length) ||
 567                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
 568                         free(buffer);
 569                         return NULL;
 570                 }
 571                 /* Now we have the ID of the referred-to object in
 572                  * actual_sha1.  Check again. */
 573         }
 574 }
 575
 576 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 577 {
 578         int size;
 579         unsigned char *compressed;
 580         z_stream stream;
 581         unsigned char sha1[20];
 582         SHA_CTX c;
 583         char *filename;
 584         static char tmpfile[PATH_MAX];
 585         unsigned char hdr[50];
 586         int fd, hdrlen, ret;
 587
 588         /* Generate the header */
 589         hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
 590
 591         /* Sha1.. */
 592         SHA1_Init(&c);
 593         SHA1_Update(&c, hdr, hdrlen);
 594         SHA1_Update(&c, buf, len);
 595         SHA1_Final(sha1, &c);
 596
 597         if (returnsha1)
 598                 memcpy(returnsha1, sha1, 20);
 599
 600         filename = sha1_file_name(sha1);
 601         fd = open(filename, O_RDONLY);
 602         if (fd >= 0) {
 603                 /*
 604                  * FIXME!!! We might do collision checking here, but we'd
 605                  * need to uncompress the old file and check it. Later.
 606                  */
 607                 close(fd);
 608                 return 0;
 609         }
 610
 611         if (errno != ENOENT) {
 612                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
 613                 return -1;
 614         }
 615
 616         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
 617
 618         fd = mkstemp(tmpfile);
 619         if (fd < 0) {
 620                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
 621                 return -1;
 622         }
 623
 624         /* Set it up */
 625         memset(&stream, 0, sizeof(stream));
 626         deflateInit(&stream, Z_BEST_COMPRESSION);
 627         size = deflateBound(&stream, len+hdrlen);
 628         compressed = xmalloc(size);
 629
 630         /* Compress it */
 631         stream.next_out = compressed;
 632         stream.avail_out = size;
 633
 634         /* First header.. */
 635         stream.next_in = hdr;
 636         stream.avail_in = hdrlen;
 637         while (deflate(&stream, 0) == Z_OK)
 638                 /* nothing */;
 639
 640         /* Then the data itself.. */
 641         stream.next_in = buf;
 642         stream.avail_in = len;
 643         while (deflate(&stream, Z_FINISH) == Z_OK)
 644                 /* nothing */;
 645         deflateEnd(&stream);
 646         size = stream.total_out;
 647
 648         if (write(fd, compressed, size) != size)
 649                 die("unable to write file");
 650         fchmod(fd, 0444);
 651         close(fd);
 652         free(compressed);
 653
 654         ret = link(tmpfile, filename);
 655         if (ret < 0) {
 656                 ret = errno;
 657
 658                 /*
 659                  * Coda hack - coda doesn't like cross-directory links,
 660                  * so we fall back to a rename, which will mean that it
 661                  * won't be able to check collisions, but that's not a
 662                  * big deal.
 663                  *
 664                  * When this succeeds, we just return 0. We have nothing
 665                  * left to unlink.
 666                  */
 667                 if (ret == EXDEV && !rename(tmpfile, filename))
 668                         return 0;
 669         }
 670         unlink(tmpfile);
 671         if (ret) {
 672                 if (ret != EEXIST) {
 673                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
 674                         return -1;
 675                 }
 676                 /* FIXME!!! Collision check here ? */
 677         }
 678
 679         return 0;
 680 }
 681
 682 int write_sha1_from_fd(const unsigned char *sha1, int fd)
 683 {
 684         char *filename = sha1_file_name(sha1);
 685
 686         int local;
 687         z_stream stream;
 688         unsigned char real_sha1[20];
 689         unsigned char buf[4096];
 690         unsigned char discard[4096];
 691         int ret;
 692         SHA_CTX c;
 693
 694         local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
 695
 696         if (local < 0)
 697                 return error("Couldn't open %s\n", filename);
 698
 699         memset(&stream, 0, sizeof(stream));
 700
 701         inflateInit(&stream);
 702
 703         SHA1_Init(&c);
 704
 705         do {
 706                 ssize_t size;
 707                 size = read(fd, buf, 4096);
 708                 if (size <= 0) {
 709                         close(local);
 710                         unlink(filename);
 711                         if (!size)
 712                                 return error("Connection closed?");
 713                         perror("Reading from connection");
 714                         return -1;
 715                 }
 716                 write(local, buf, size);
 717                 stream.avail_in = size;
 718                 stream.next_in = buf;
 719                 do {
 720                         stream.next_out = discard;
 721                         stream.avail_out = sizeof(discard);
 722                         ret = inflate(&stream, Z_SYNC_FLUSH);
 723                         SHA1_Update(&c, discard, sizeof(discard) -
 724                                     stream.avail_out);
 725                 } while (stream.avail_in && ret == Z_OK);
 726
 727         } while (ret == Z_OK);
 728         inflateEnd(&stream);
 729
 730         close(local);
 731         SHA1_Final(real_sha1, &c);
 732         if (ret != Z_STREAM_END) {
 733                 unlink(filename);
 734                 return error("File %s corrupted", sha1_to_hex(sha1));
 735         }
 736         if (memcmp(sha1, real_sha1, 20)) {
 737                 unlink(filename);
 738                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
 739         }
 740
 741         return 0;
 742 }
 743
 744 int has_sha1_file(const unsigned char *sha1)
 745 {
 746         struct stat st;
 747         return !!find_sha1_file(sha1, &st);
 748 }
 749
 750 int index_fd(unsigned char *sha1, int fd, struct stat *st)
 751 {
 752         unsigned long size = st->st_size;
 753         void *buf;
 754         int ret;
 755
 756         buf = "";
 757         if (size)
 758                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
 759         close(fd);
 760         if ((int)(long)buf == -1)
 761                 return -1;
 762
 763         ret = write_sha1_file(buf, size, "blob", sha1);
 764         if (size)
 765                 munmap(buf, size);
 766         return ret;
 767 }