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 <sys/types.h>
  10 #include <dirent.h>
  11 #include "cache.h"
  12 #include "delta.h"
  13 #include "pack.h"
  14
  15 #ifndef O_NOATIME
  16 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  17 #define O_NOATIME 01000000
  18 #else
  19 #define O_NOATIME 0
  20 #endif
  21 #endif
  22
  23 static unsigned int sha1_file_open_flag = O_NOATIME;
  24
  25 static unsigned hexval(char c)
  26 {
  27         if (c >= '0' && c <= '9')
  28                 return c - '0';
  29         if (c >= 'a' && c <= 'f')
  30                 return c - 'a' + 10;
  31         if (c >= 'A' && c <= 'F')
  32                 return c - 'A' + 10;
  33         return ~0;
  34 }
  35
  36 int get_sha1_hex(const char *hex, unsigned char *sha1)
  37 {
  38         int i;
  39         for (i = 0; i < 20; i++) {
  40                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  41                 if (val & ~0xff)
  42                         return -1;
  43                 *sha1++ = val;
  44                 hex += 2;
  45         }
  46         return 0;
  47 }
  48
  49 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
  50         *git_graft_file;
  51 static void setup_git_env(void)
  52 {
  53         git_dir = gitenv(GIT_DIR_ENVIRONMENT);
  54         if (!git_dir)
  55                 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
  56         git_object_dir = gitenv(DB_ENVIRONMENT);
  57         if (!git_object_dir) {
  58                 git_object_dir = xmalloc(strlen(git_dir) + 9);
  59                 sprintf(git_object_dir, "%s/objects", git_dir);
  60         }
  61         git_refs_dir = xmalloc(strlen(git_dir) + 6);
  62         sprintf(git_refs_dir, "%s/refs", git_dir);
  63         git_index_file = gitenv(INDEX_ENVIRONMENT);
  64         if (!git_index_file) {
  65                 git_index_file = xmalloc(strlen(git_dir) + 7);
  66                 sprintf(git_index_file, "%s/index", git_dir);
  67         }
  68         git_graft_file = gitenv(GRAFT_ENVIRONMENT);
  69         if (!git_graft_file)
  70                 git_graft_file = strdup(git_path("info/grafts"));
  71 }
  72
  73 char *get_object_directory(void)
  74 {
  75         if (!git_object_dir)
  76                 setup_git_env();
  77         return git_object_dir;
  78 }
  79
  80 char *get_refs_directory(void)
  81 {
  82         if (!git_refs_dir)
  83                 setup_git_env();
  84         return git_refs_dir;
  85 }
  86
  87 char *get_index_file(void)
  88 {
  89         if (!git_index_file)
  90                 setup_git_env();
  91         return git_index_file;
  92 }
  93
  94 char *get_graft_file(void)
  95 {
  96         if (!git_graft_file)
  97                 setup_git_env();
  98         return git_graft_file;
  99 }
 100
 101 int safe_create_leading_directories(char *path)
 102 {
 103         char *pos = path;
 104
 105         while (pos) {
 106                 pos = strchr(pos, '/');
 107                 if (!pos)
 108                         break;
 109                 *pos = 0;
 110                 if (mkdir(path, 0777) < 0)
 111                         if (errno != EEXIST) {
 112                                 *pos = '/';
 113                                 return -1;
 114                         }
 115                 *pos++ = '/';
 116         }
 117         return 0;
 118 }
 119
 120 char * sha1_to_hex(const unsigned char *sha1)
 121 {
 122         static char buffer[50];
 123         static const char hex[] = "0123456789abcdef";
 124         char *buf = buffer;
 125         int i;
 126
 127         for (i = 0; i < 20; i++) {
 128                 unsigned int val = *sha1++;
 129                 *buf++ = hex[val >> 4];
 130                 *buf++ = hex[val & 0xf];
 131         }
 132         return buffer;
 133 }
 134
 135 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 136 {
 137         int i;
 138         for (i = 0; i < 20; i++) {
 139                 static char hex[] = "0123456789abcdef";
 140                 unsigned int val = sha1[i];
 141                 char *pos = pathbuf + i*2 + (i > 0);
 142                 *pos++ = hex[val >> 4];
 143                 *pos = hex[val & 0xf];
 144         }
 145 }
 146
 147 /*
 148  * NOTE! This returns a statically allocated buffer, so you have to be
 149  * careful about using it. Do a "strdup()" if you need to save the
 150  * filename.
 151  *
 152  * Also note that this returns the location for creating.  Reading
 153  * SHA1 file can happen from any alternate directory listed in the
 154  * DB_ENVIRONMENT environment variable if it is not found in
 155  * the primary object database.
 156  */
 157 char *sha1_file_name(const unsigned char *sha1)
 158 {
 159         static char *name, *base;
 160
 161         if (!base) {
 162                 const char *sha1_file_directory = get_object_directory();
 163                 int len = strlen(sha1_file_directory);
 164                 base = xmalloc(len + 60);
 165                 memcpy(base, sha1_file_directory, len);
 166                 memset(base+len, 0, 60);
 167                 base[len] = '/';
 168                 base[len+3] = '/';
 169                 name = base + len + 1;
 170         }
 171         fill_sha1_path(name, sha1);
 172         return base;
 173 }
 174
 175 char *sha1_pack_name(const unsigned char *sha1)
 176 {
 177         static const char hex[] = "0123456789abcdef";
 178         static char *name, *base, *buf;
 179         int i;
 180
 181         if (!base) {
 182                 const char *sha1_file_directory = get_object_directory();
 183                 int len = strlen(sha1_file_directory);
 184                 base = xmalloc(len + 60);
 185                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 186                 name = base + len + 11;
 187         }
 188
 189         buf = name;
 190
 191         for (i = 0; i < 20; i++) {
 192                 unsigned int val = *sha1++;
 193                 *buf++ = hex[val >> 4];
 194                 *buf++ = hex[val & 0xf];
 195         }
 196
 197         return base;
 198 }
 199
 200 char *sha1_pack_index_name(const unsigned char *sha1)
 201 {
 202         static const char hex[] = "0123456789abcdef";
 203         static char *name, *base, *buf;
 204         int i;
 205
 206         if (!base) {
 207                 const char *sha1_file_directory = get_object_directory();
 208                 int len = strlen(sha1_file_directory);
 209                 base = xmalloc(len + 60);
 210                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 211                 name = base + len + 11;
 212         }
 213
 214         buf = name;
 215
 216         for (i = 0; i < 20; i++) {
 217                 unsigned int val = *sha1++;
 218                 *buf++ = hex[val >> 4];
 219                 *buf++ = hex[val & 0xf];
 220         }
 221
 222         return base;
 223 }
 224
 225 struct alternate_object_database *alt_odb_list;
 226 static struct alternate_object_database **alt_odb_tail;
 227
 228 /*
 229  * Prepare alternate object database registry.
 230  *
 231  * The variable alt_odb_list points at the list of struct
 232  * alternate_object_database.  The elements on this list come from
 233  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 234  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 235  * whose contents is exactly in the same format as that environment
 236  * variable.  Its base points at a statically allocated buffer that
 237  * contains "/the/directory/corresponding/to/.git/objects/...", while
 238  * its name points just after the slash at the end of ".git/objects/"
 239  * in the example above, and has enough space to hold 40-byte hex
 240  * SHA1, an extra slash for the first level indirection, and the
 241  * terminating NUL.
 242  */
 243 static void link_alt_odb_entries(const char *alt, const char *ep, int sep)
 244 {
 245         const char *cp, *last;
 246         struct alternate_object_database *ent;
 247
 248         last = alt;
 249         while (last < ep) {
 250                 cp = last;
 251                 if (cp < ep && *cp == '#') {
 252                         while (cp < ep && *cp != sep)
 253                                 cp++;
 254                         last = cp + 1;
 255                         continue;
 256                 }
 257                 for ( ; cp < ep && *cp != sep; cp++)
 258                         ;
 259                 if (last != cp) {
 260                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 261                         int pfxlen = cp - last;
 262                         int entlen = pfxlen + 43;
 263
 264                         ent = xmalloc(sizeof(*ent) + entlen);
 265                         *alt_odb_tail = ent;
 266                         alt_odb_tail = &(ent->next);
 267                         ent->next = NULL;
 268
 269                         memcpy(ent->base, last, pfxlen);
 270                         ent->name = ent->base + pfxlen + 1;
 271                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 272                         ent->base[entlen-1] = 0;
 273                 }
 274                 while (cp < ep && *cp == sep)
 275                         cp++;
 276                 last = cp;
 277         }
 278 }
 279
 280 void prepare_alt_odb(void)
 281 {
 282         char path[PATH_MAX];
 283         char *map;
 284         int fd;
 285         struct stat st;
 286         char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";
 287
 288         sprintf(path, "%s/info/alternates", get_object_directory());
 289         if (alt_odb_tail)
 290                 return;
 291         alt_odb_tail = &alt_odb_list;
 292         link_alt_odb_entries(alt, alt + strlen(alt), ':');
 293
 294         fd = open(path, O_RDONLY);
 295         if (fd < 0)
 296                 return;
 297         if (fstat(fd, &st) || (st.st_size == 0)) {
 298                 close(fd);
 299                 return;
 300         }
 301         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 302         close(fd);
 303         if (map == MAP_FAILED)
 304                 return;
 305
 306         link_alt_odb_entries(map, map + st.st_size, '\n');
 307         munmap(map, st.st_size);
 308 }
 309
 310 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 311 {
 312         char *name = sha1_file_name(sha1);
 313         struct alternate_object_database *alt;
 314
 315         if (!stat(name, st))
 316                 return name;
 317         prepare_alt_odb();
 318         for (alt = alt_odb_list; alt; alt = alt->next) {
 319                 name = alt->name;
 320                 fill_sha1_path(name, sha1);
 321                 if (!stat(alt->base, st))
 322                         return alt->base;
 323         }
 324         return NULL;
 325 }
 326
 327 #define PACK_MAX_SZ (1<<26)
 328 static int pack_used_ctr;
 329 static unsigned long pack_mapped;
 330 struct packed_git *packed_git;
 331
 332 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 333                                 void **idx_map_)
 334 {
 335         void *idx_map;
 336         unsigned int *index;
 337         unsigned long idx_size;
 338         int nr, i;
 339         int fd = open(path, O_RDONLY);
 340         struct stat st;
 341         if (fd < 0)
 342                 return -1;
 343         if (fstat(fd, &st)) {
 344                 close(fd);
 345                 return -1;
 346         }
 347         idx_size = st.st_size;
 348         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 349         close(fd);
 350         if (idx_map == MAP_FAILED)
 351                 return -1;
 352
 353         index = idx_map;
 354         *idx_map_ = idx_map;
 355         *idx_size_ = idx_size;
 356
 357         /* check index map */
 358         if (idx_size < 4*256 + 20 + 20)
 359                 return error("index file too small");
 360         nr = 0;
 361         for (i = 0; i < 256; i++) {
 362                 unsigned int n = ntohl(index[i]);
 363                 if (n < nr)
 364                         return error("non-monotonic index");
 365                 nr = n;
 366         }
 367
 368         /*
 369          * Total size:
 370          *  - 256 index entries 4 bytes each
 371          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 372          *  - 20-byte SHA1 of the packfile
 373          *  - 20-byte SHA1 file checksum
 374          */
 375         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 376                 return error("wrong index file size");
 377
 378         return 0;
 379 }
 380
 381 static int unuse_one_packed_git(void)
 382 {
 383         struct packed_git *p, *lru = NULL;
 384
 385         for (p = packed_git; p; p = p->next) {
 386                 if (p->pack_use_cnt || !p->pack_base)
 387                         continue;
 388                 if (!lru || p->pack_last_used < lru->pack_last_used)
 389                         lru = p;
 390         }
 391         if (!lru)
 392                 return 0;
 393         munmap(lru->pack_base, lru->pack_size);
 394         lru->pack_base = NULL;
 395         return 1;
 396 }
 397
 398 void unuse_packed_git(struct packed_git *p)
 399 {
 400         p->pack_use_cnt--;
 401 }
 402
 403 int use_packed_git(struct packed_git *p)
 404 {
 405         if (!p->pack_size) {
 406                 struct stat st;
 407                 // We created the struct before we had the pack
 408                 stat(p->pack_name, &st);
 409                 if (!S_ISREG(st.st_mode))
 410                         die("packfile %s not a regular file", p->pack_name);
 411                 p->pack_size = st.st_size;
 412         }
 413         if (!p->pack_base) {
 414                 int fd;
 415                 struct stat st;
 416                 void *map;
 417
 418                 pack_mapped += p->pack_size;
 419                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 420                         ; /* nothing */
 421                 fd = open(p->pack_name, O_RDONLY);
 422                 if (fd < 0)
 423                         die("packfile %s cannot be opened", p->pack_name);
 424                 if (fstat(fd, &st)) {
 425                         close(fd);
 426                         die("packfile %s cannot be opened", p->pack_name);
 427                 }
 428                 if (st.st_size != p->pack_size)
 429                         die("packfile %s size mismatch.", p->pack_name);
 430                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 431                 close(fd);
 432                 if (map == MAP_FAILED)
 433                         die("packfile %s cannot be mapped.", p->pack_name);
 434                 p->pack_base = map;
 435
 436                 /* Check if the pack file matches with the index file.
 437                  * this is cheap.
 438                  */
 439                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 440                            p->pack_base + p->pack_size - 20, 20)) {
 441
 442                         die("packfile %s does not match index.", p->pack_name);
 443                 }
 444         }
 445         p->pack_last_used = pack_used_ctr++;
 446         p->pack_use_cnt++;
 447         return 0;
 448 }
 449
 450 struct packed_git *add_packed_git(char *path, int path_len)
 451 {
 452         struct stat st;
 453         struct packed_git *p;
 454         unsigned long idx_size;
 455         void *idx_map;
 456
 457         if (check_packed_git_idx(path, &idx_size, &idx_map))
 458                 return NULL;
 459
 460         /* do we have a corresponding .pack file? */
 461         strcpy(path + path_len - 4, ".pack");
 462         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 463                 munmap(idx_map, idx_size);
 464                 return NULL;
 465         }
 466         /* ok, it looks sane as far as we can check without
 467          * actually mapping the pack file.
 468          */
 469         p = xmalloc(sizeof(*p) + path_len + 2);
 470         strcpy(p->pack_name, path);
 471         p->index_size = idx_size;
 472         p->pack_size = st.st_size;
 473         p->index_base = idx_map;
 474         p->next = NULL;
 475         p->pack_base = NULL;
 476         p->pack_last_used = 0;
 477         p->pack_use_cnt = 0;
 478         return p;
 479 }
 480
 481 struct packed_git *parse_pack_index(unsigned char *sha1)
 482 {
 483         char *path = sha1_pack_index_name(sha1);
 484         return parse_pack_index_file(sha1, path);
 485 }
 486
 487 struct packed_git *parse_pack_index_file(unsigned char *sha1, char *idx_path)
 488 {
 489         struct packed_git *p;
 490         unsigned long idx_size;
 491         void *idx_map;
 492         char *path;
 493
 494         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 495                 return NULL;
 496
 497         path = sha1_pack_name(sha1);
 498
 499         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 500         strcpy(p->pack_name, path);
 501         p->index_size = idx_size;
 502         p->pack_size = 0;
 503         p->index_base = idx_map;
 504         p->next = NULL;
 505         p->pack_base = NULL;
 506         p->pack_last_used = 0;
 507         p->pack_use_cnt = 0;
 508         memcpy(p->sha1, sha1, 20);
 509         return p;
 510 }
 511
 512 void install_packed_git(struct packed_git *pack)
 513 {
 514         pack->next = packed_git;
 515         packed_git = pack;
 516 }
 517
 518 static void prepare_packed_git_one(char *objdir)
 519 {
 520         char path[PATH_MAX];
 521         int len;
 522         DIR *dir;
 523         struct dirent *de;
 524
 525         sprintf(path, "%s/pack", objdir);
 526         len = strlen(path);
 527         dir = opendir(path);
 528         if (!dir)
 529                 return;
 530         path[len++] = '/';
 531         while ((de = readdir(dir)) != NULL) {
 532                 int namelen = strlen(de->d_name);
 533                 struct packed_git *p;
 534
 535                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 536                         continue;
 537
 538                 /* we have .idx.  Is it a file we can map? */
 539                 strcpy(path + len, de->d_name);
 540                 p = add_packed_git(path, len + namelen);
 541                 if (!p)
 542                         continue;
 543                 p->next = packed_git;
 544                 packed_git = p;
 545         }
 546         closedir(dir);
 547 }
 548
 549 void prepare_packed_git(void)
 550 {
 551         static int run_once = 0;
 552         struct alternate_object_database *alt;
 553
 554         if (run_once)
 555                 return;
 556         prepare_packed_git_one(get_object_directory());
 557         prepare_alt_odb();
 558         for (alt = alt_odb_list; alt; alt = alt->next) {
 559                 alt->name[0] = 0;
 560                 prepare_packed_git_one(alt->base);
 561         }
 562         run_once = 1;
 563 }
 564
 565 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 566 {
 567         char header[100];
 568         unsigned char real_sha1[20];
 569         SHA_CTX c;
 570
 571         SHA1_Init(&c);
 572         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 573         SHA1_Update(&c, map, size);
 574         SHA1_Final(real_sha1, &c);
 575         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 576 }
 577
 578 static void *map_sha1_file_internal(const unsigned char *sha1,
 579                                     unsigned long *size)
 580 {
 581         struct stat st;
 582         void *map;
 583         int fd;
 584         char *filename = find_sha1_file(sha1, &st);
 585
 586         if (!filename) {
 587                 return NULL;
 588         }
 589
 590         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 591         if (fd < 0) {
 592                 /* See if it works without O_NOATIME */
 593                 switch (sha1_file_open_flag) {
 594                 default:
 595                         fd = open(filename, O_RDONLY);
 596                         if (fd >= 0)
 597                                 break;
 598                 /* Fallthrough */
 599                 case 0:
 600                         return NULL;
 601                 }
 602
 603                 /* If it failed once, it will probably fail again.
 604                  * Stop using O_NOATIME
 605                  */
 606                 sha1_file_open_flag = 0;
 607         }
 608         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 609         close(fd);
 610         if (map == MAP_FAILED)
 611                 return NULL;
 612         *size = st.st_size;
 613         return map;
 614 }
 615
 616 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 617 {
 618         /* Get the data stream */
 619         memset(stream, 0, sizeof(*stream));
 620         stream->next_in = map;
 621         stream->avail_in = mapsize;
 622         stream->next_out = buffer;
 623         stream->avail_out = size;
 624
 625         inflateInit(stream);
 626         return inflate(stream, 0);
 627 }
 628
 629 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 630 {
 631         int bytes = strlen(buffer) + 1;
 632         unsigned char *buf = xmalloc(1+size);
 633
 634         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 635         bytes = stream->total_out - bytes;
 636         if (bytes < size) {
 637                 stream->next_out = buf + bytes;
 638                 stream->avail_out = size - bytes;
 639                 while (inflate(stream, Z_FINISH) == Z_OK)
 640                         /* nothing */;
 641         }
 642         buf[size] = 0;
 643         inflateEnd(stream);
 644         return buf;
 645 }
 646
 647 /*
 648  * We used to just use "sscanf()", but that's actually way
 649  * too permissive for what we want to check. So do an anal
 650  * object header parse by hand.
 651  */
 652 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 653 {
 654         int i;
 655         unsigned long size;
 656
 657         /*
 658          * The type can be at most ten bytes (including the
 659          * terminating '\0' that we add), and is followed by
 660          * a space.
 661          */
 662         i = 10;
 663         for (;;) {
 664                 char c = *hdr++;
 665                 if (c == ' ')
 666                         break;
 667                 if (!--i)
 668                         return -1;
 669                 *type++ = c;
 670         }
 671         *type = 0;
 672
 673         /*
 674          * The length must follow immediately, and be in canonical
 675          * decimal format (ie "010" is not valid).
 676          */
 677         size = *hdr++ - '0';
 678         if (size > 9)
 679                 return -1;
 680         if (size) {
 681                 for (;;) {
 682                         unsigned long c = *hdr - '0';
 683                         if (c > 9)
 684                                 break;
 685                         hdr++;
 686                         size = size * 10 + c;
 687                 }
 688         }
 689         *sizep = size;
 690
 691         /*
 692          * The length must be followed by a zero byte
 693          */
 694         return *hdr ? -1 : 0;
 695 }
 696
 697 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 698 {
 699         int ret;
 700         z_stream stream;
 701         char hdr[8192];
 702
 703         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 704         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 705                 return NULL;
 706
 707         return unpack_sha1_rest(&stream, hdr, *size);
 708 }
 709
 710 /* forward declaration for a mutually recursive function */
 711 static int packed_object_info(struct pack_entry *entry,
 712                               char *type, unsigned long *sizep);
 713
 714 static int packed_delta_info(unsigned char *base_sha1,
 715                              unsigned long delta_size,
 716                              unsigned long left,
 717                              char *type,
 718                              unsigned long *sizep,
 719                              struct packed_git *p)
 720 {
 721         struct pack_entry base_ent;
 722
 723         if (left < 20)
 724                 die("truncated pack file");
 725
 726         /* The base entry _must_ be in the same pack */
 727         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 728                 die("failed to find delta-pack base object %s",
 729                     sha1_to_hex(base_sha1));
 730
 731         /* We choose to only get the type of the base object and
 732          * ignore potentially corrupt pack file that expects the delta
 733          * based on a base with a wrong size.  This saves tons of
 734          * inflate() calls.
 735          */
 736
 737         if (packed_object_info(&base_ent, type, NULL))
 738                 die("cannot get info for delta-pack base");
 739
 740         if (sizep) {
 741                 const unsigned char *data;
 742                 unsigned char delta_head[64];
 743                 unsigned long result_size;
 744                 z_stream stream;
 745                 int st;
 746
 747                 memset(&stream, 0, sizeof(stream));
 748
 749                 data = stream.next_in = base_sha1 + 20;
 750                 stream.avail_in = left - 20;
 751                 stream.next_out = delta_head;
 752                 stream.avail_out = sizeof(delta_head);
 753
 754                 inflateInit(&stream);
 755                 st = inflate(&stream, Z_FINISH);
 756                 inflateEnd(&stream);
 757                 if ((st != Z_STREAM_END) &&
 758                     stream.total_out != sizeof(delta_head))
 759                         die("delta data unpack-initial failed");
 760
 761                 /* Examine the initial part of the delta to figure out
 762                  * the result size.
 763                  */
 764                 data = delta_head;
 765                 get_delta_hdr_size(&data); /* ignore base size */
 766
 767                 /* Read the result size */
 768                 result_size = get_delta_hdr_size(&data);
 769                 *sizep = result_size;
 770         }
 771         return 0;
 772 }
 773
 774 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 775         enum object_type *type, unsigned long *sizep)
 776 {
 777         unsigned shift;
 778         unsigned char *pack, c;
 779         unsigned long size;
 780
 781         if (offset >= p->pack_size)
 782                 die("object offset outside of pack file");
 783
 784         pack =  p->pack_base + offset;
 785         c = *pack++;
 786         offset++;
 787         *type = (c >> 4) & 7;
 788         size = c & 15;
 789         shift = 4;
 790         while (c & 0x80) {
 791                 if (offset >= p->pack_size)
 792                         die("object offset outside of pack file");
 793                 c = *pack++;
 794                 offset++;
 795                 size += (c & 0x7f) << shift;
 796                 shift += 7;
 797         }
 798         *sizep = size;
 799         return offset;
 800 }
 801
 802 void packed_object_info_detail(struct pack_entry *e,
 803                                char *type,
 804                                unsigned long *size,
 805                                unsigned long *store_size,
 806                                int *delta_chain_length,
 807                                unsigned char *base_sha1)
 808 {
 809         struct packed_git *p = e->p;
 810         unsigned long offset, left;
 811         unsigned char *pack;
 812         enum object_type kind;
 813
 814         offset = unpack_object_header(p, e->offset, &kind, size);
 815         pack = p->pack_base + offset;
 816         left = p->pack_size - offset;
 817         if (kind != OBJ_DELTA)
 818                 *delta_chain_length = 0;
 819         else {
 820                 int chain_length = 0;
 821                 memcpy(base_sha1, pack, 20);
 822                 do {
 823                         struct pack_entry base_ent;
 824                         unsigned long junk;
 825
 826                         find_pack_entry_one(pack, &base_ent, p);
 827                         offset = unpack_object_header(p, base_ent.offset,
 828                                                       &kind, &junk);
 829                         pack = p->pack_base + offset;
 830                         chain_length++;
 831                 } while (kind == OBJ_DELTA);
 832                 *delta_chain_length = chain_length;
 833         }
 834         switch (kind) {
 835         case OBJ_COMMIT:
 836                 strcpy(type, "commit");
 837                 break;
 838         case OBJ_TREE:
 839                 strcpy(type, "tree");
 840                 break;
 841         case OBJ_BLOB:
 842                 strcpy(type, "blob");
 843                 break;
 844         case OBJ_TAG:
 845                 strcpy(type, "tag");
 846                 break;
 847         default:
 848                 die("corrupted pack file");
 849         }
 850         *store_size = 0; /* notyet */
 851 }
 852
 853 static int packed_object_info(struct pack_entry *entry,
 854                               char *type, unsigned long *sizep)
 855 {
 856         struct packed_git *p = entry->p;
 857         unsigned long offset, size, left;
 858         unsigned char *pack;
 859         enum object_type kind;
 860         int retval;
 861
 862         if (use_packed_git(p))
 863                 die("cannot map packed file");
 864
 865         offset = unpack_object_header(p, entry->offset, &kind, &size);
 866         pack = p->pack_base + offset;
 867         left = p->pack_size - offset;
 868
 869         switch (kind) {
 870         case OBJ_DELTA:
 871                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 872                 unuse_packed_git(p);
 873                 return retval;
 874         case OBJ_COMMIT:
 875                 strcpy(type, "commit");
 876                 break;
 877         case OBJ_TREE:
 878                 strcpy(type, "tree");
 879                 break;
 880         case OBJ_BLOB:
 881                 strcpy(type, "blob");
 882                 break;
 883         case OBJ_TAG:
 884                 strcpy(type, "tag");
 885                 break;
 886         default:
 887                 die("corrupted pack file");
 888         }
 889         if (sizep)
 890                 *sizep = size;
 891         unuse_packed_git(p);
 892         return 0;
 893 }
 894
 895 /* forward declaration for a mutually recursive function */
 896 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 897
 898 static void *unpack_delta_entry(unsigned char *base_sha1,
 899                                 unsigned long delta_size,
 900                                 unsigned long left,
 901                                 char *type,
 902                                 unsigned long *sizep,
 903                                 struct packed_git *p)
 904 {
 905         struct pack_entry base_ent;
 906         void *data, *delta_data, *result, *base;
 907         unsigned long data_size, result_size, base_size;
 908         z_stream stream;
 909         int st;
 910
 911         if (left < 20)
 912                 die("truncated pack file");
 913         data = base_sha1 + 20;
 914         data_size = left - 20;
 915         delta_data = xmalloc(delta_size);
 916
 917         memset(&stream, 0, sizeof(stream));
 918
 919         stream.next_in = data;
 920         stream.avail_in = data_size;
 921         stream.next_out = delta_data;
 922         stream.avail_out = delta_size;
 923
 924         inflateInit(&stream);
 925         st = inflate(&stream, Z_FINISH);
 926         inflateEnd(&stream);
 927         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 928                 die("delta data unpack failed");
 929
 930         /* The base entry _must_ be in the same pack */
 931         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 932                 die("failed to find delta-pack base object %s",
 933                     sha1_to_hex(base_sha1));
 934         base = unpack_entry_gently(&base_ent, type, &base_size);
 935         if (!base)
 936                 die("failed to read delta-pack base object %s",
 937                     sha1_to_hex(base_sha1));
 938         result = patch_delta(base, base_size,
 939                              delta_data, delta_size,
 940                              &result_size);
 941         if (!result)
 942                 die("failed to apply delta");
 943         free(delta_data);
 944         free(base);
 945         *sizep = result_size;
 946         return result;
 947 }
 948
 949 static void *unpack_non_delta_entry(unsigned char *data,
 950                                     unsigned long size,
 951                                     unsigned long left)
 952 {
 953         int st;
 954         z_stream stream;
 955         unsigned char *buffer;
 956
 957         buffer = xmalloc(size + 1);
 958         buffer[size] = 0;
 959         memset(&stream, 0, sizeof(stream));
 960         stream.next_in = data;
 961         stream.avail_in = left;
 962         stream.next_out = buffer;
 963         stream.avail_out = size;
 964
 965         inflateInit(&stream);
 966         st = inflate(&stream, Z_FINISH);
 967         inflateEnd(&stream);
 968         if ((st != Z_STREAM_END) || stream.total_out != size) {
 969                 free(buffer);
 970                 return NULL;
 971         }
 972
 973         return buffer;
 974 }
 975
 976 static void *unpack_entry(struct pack_entry *entry,
 977                           char *type, unsigned long *sizep)
 978 {
 979         struct packed_git *p = entry->p;
 980         void *retval;
 981
 982         if (use_packed_git(p))
 983                 die("cannot map packed file");
 984         retval = unpack_entry_gently(entry, type, sizep);
 985         unuse_packed_git(p);
 986         if (!retval)
 987                 die("corrupted pack file");
 988         return retval;
 989 }
 990
 991 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 992 void *unpack_entry_gently(struct pack_entry *entry,
 993                           char *type, unsigned long *sizep)
 994 {
 995         struct packed_git *p = entry->p;
 996         unsigned long offset, size, left;
 997         unsigned char *pack;
 998         enum object_type kind;
 999         void *retval;
1000
1001         offset = unpack_object_header(p, entry->offset, &kind, &size);
1002         pack = p->pack_base + offset;
1003         left = p->pack_size - offset;
1004         switch (kind) {
1005         case OBJ_DELTA:
1006                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1007                 return retval;
1008         case OBJ_COMMIT:
1009                 strcpy(type, "commit");
1010                 break;
1011         case OBJ_TREE:
1012                 strcpy(type, "tree");
1013                 break;
1014         case OBJ_BLOB:
1015                 strcpy(type, "blob");
1016                 break;
1017         case OBJ_TAG:
1018                 strcpy(type, "tag");
1019                 break;
1020         default:
1021                 return NULL;
1022         }
1023         *sizep = size;
1024         retval = unpack_non_delta_entry(pack, size, left);
1025         return retval;
1026 }
1027
1028 int num_packed_objects(const struct packed_git *p)
1029 {
1030         /* See check_packed_git_idx() */
1031         return (p->index_size - 20 - 20 - 4*256) / 24;
1032 }
1033
1034 int nth_packed_object_sha1(const struct packed_git *p, int n,
1035                            unsigned char* sha1)
1036 {
1037         void *index = p->index_base + 256;
1038         if (n < 0 || num_packed_objects(p) <= n)
1039                 return -1;
1040         memcpy(sha1, (index + 24 * n + 4), 20);
1041         return 0;
1042 }
1043
1044 int find_pack_entry_one(const unsigned char *sha1,
1045                         struct pack_entry *e, struct packed_git *p)
1046 {
1047         unsigned int *level1_ofs = p->index_base;
1048         int hi = ntohl(level1_ofs[*sha1]);
1049         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1050         void *index = p->index_base + 256;
1051
1052         do {
1053                 int mi = (lo + hi) / 2;
1054                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1055                 if (!cmp) {
1056                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1057                         memcpy(e->sha1, sha1, 20);
1058                         e->p = p;
1059                         return 1;
1060                 }
1061                 if (cmp > 0)
1062                         hi = mi;
1063                 else
1064                         lo = mi+1;
1065         } while (lo < hi);
1066         return 0;
1067 }
1068
1069 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1070 {
1071         struct packed_git *p;
1072         prepare_packed_git();
1073
1074         for (p = packed_git; p; p = p->next) {
1075                 if (find_pack_entry_one(sha1, e, p))
1076                         return 1;
1077         }
1078         return 0;
1079 }
1080
1081 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1082                                   struct packed_git *packs)
1083 {
1084         struct packed_git *p;
1085         struct pack_entry e;
1086
1087         for (p = packs; p; p = p->next) {
1088                 if (find_pack_entry_one(sha1, &e, p))
1089                         return p;
1090         }
1091         return NULL;
1092
1093 }
1094
1095 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1096 {
1097         int status;
1098         unsigned long mapsize, size;
1099         void *map;
1100         z_stream stream;
1101         char hdr[128];
1102
1103         map = map_sha1_file_internal(sha1, &mapsize);
1104         if (!map) {
1105                 struct pack_entry e;
1106
1107                 if (!find_pack_entry(sha1, &e))
1108                         return error("unable to find %s", sha1_to_hex(sha1));
1109                 return packed_object_info(&e, type, sizep);
1110         }
1111         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1112                 status = error("unable to unpack %s header",
1113                                sha1_to_hex(sha1));
1114         if (parse_sha1_header(hdr, type, &size) < 0)
1115                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1116         else {
1117                 status = 0;
1118                 if (sizep)
1119                         *sizep = size;
1120         }
1121         inflateEnd(&stream);
1122         munmap(map, mapsize);
1123         return status;
1124 }
1125
1126 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1127 {
1128         struct pack_entry e;
1129
1130         if (!find_pack_entry(sha1, &e)) {
1131                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1132                 return NULL;
1133         }
1134         return unpack_entry(&e, type, size);
1135 }
1136
1137 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1138 {
1139         unsigned long mapsize;
1140         void *map, *buf;
1141         struct pack_entry e;
1142
1143         if (find_pack_entry(sha1, &e))
1144                 return read_packed_sha1(sha1, type, size);
1145         map = map_sha1_file_internal(sha1, &mapsize);
1146         if (map) {
1147                 buf = unpack_sha1_file(map, mapsize, type, size);
1148                 munmap(map, mapsize);
1149                 return buf;
1150         }
1151         return NULL;
1152 }
1153
1154 void *read_object_with_reference(const unsigned char *sha1,
1155                                  const char *required_type,
1156                                  unsigned long *size,
1157                                  unsigned char *actual_sha1_return)
1158 {
1159         char type[20];
1160         void *buffer;
1161         unsigned long isize;
1162         unsigned char actual_sha1[20];
1163
1164         memcpy(actual_sha1, sha1, 20);
1165         while (1) {
1166                 int ref_length = -1;
1167                 const char *ref_type = NULL;
1168
1169                 buffer = read_sha1_file(actual_sha1, type, &isize);
1170                 if (!buffer)
1171                         return NULL;
1172                 if (!strcmp(type, required_type)) {
1173                         *size = isize;
1174                         if (actual_sha1_return)
1175                                 memcpy(actual_sha1_return, actual_sha1, 20);
1176                         return buffer;
1177                 }
1178                 /* Handle references */
1179                 else if (!strcmp(type, "commit"))
1180                         ref_type = "tree ";
1181                 else if (!strcmp(type, "tag"))
1182                         ref_type = "object ";
1183                 else {
1184                         free(buffer);
1185                         return NULL;
1186                 }
1187                 ref_length = strlen(ref_type);
1188
1189                 if (memcmp(buffer, ref_type, ref_length) ||
1190                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1191                         free(buffer);
1192                         return NULL;
1193                 }
1194                 free(buffer);
1195                 /* Now we have the ID of the referred-to object in
1196                  * actual_sha1.  Check again. */
1197         }
1198 }
1199
1200 char *write_sha1_file_prepare(void *buf,
1201                               unsigned long len,
1202                               const char *type,
1203                               unsigned char *sha1,
1204                               unsigned char *hdr,
1205                               int *hdrlen)
1206 {
1207         SHA_CTX c;
1208
1209         /* Generate the header */
1210         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1211
1212         /* Sha1.. */
1213         SHA1_Init(&c);
1214         SHA1_Update(&c, hdr, *hdrlen);
1215         SHA1_Update(&c, buf, len);
1216         SHA1_Final(sha1, &c);
1217
1218         return sha1_file_name(sha1);
1219 }
1220
1221 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1222 {
1223         int size;
1224         unsigned char *compressed;
1225         z_stream stream;
1226         unsigned char sha1[20];
1227         char *filename;
1228         static char tmpfile[PATH_MAX];
1229         unsigned char hdr[50];
1230         int fd, hdrlen, ret;
1231
1232         /* Normally if we have it in the pack then we do not bother writing
1233          * it out into .git/objects/??/?{38} file.
1234          */
1235         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1236         if (returnsha1)
1237                 memcpy(returnsha1, sha1, 20);
1238         if (has_sha1_file(sha1))
1239                 return 0;
1240         fd = open(filename, O_RDONLY);
1241         if (fd >= 0) {
1242                 /*
1243                  * FIXME!!! We might do collision checking here, but we'd
1244                  * need to uncompress the old file and check it. Later.
1245                  */
1246                 close(fd);
1247                 return 0;
1248         }
1249
1250         if (errno != ENOENT) {
1251                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1252                 return -1;
1253         }
1254
1255         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1256
1257         fd = mkstemp(tmpfile);
1258         if (fd < 0) {
1259                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1260                 return -1;
1261         }
1262
1263         /* Set it up */
1264         memset(&stream, 0, sizeof(stream));
1265         deflateInit(&stream, Z_BEST_COMPRESSION);
1266         size = deflateBound(&stream, len+hdrlen);
1267         compressed = xmalloc(size);
1268
1269         /* Compress it */
1270         stream.next_out = compressed;
1271         stream.avail_out = size;
1272
1273         /* First header.. */
1274         stream.next_in = hdr;
1275         stream.avail_in = hdrlen;
1276         while (deflate(&stream, 0) == Z_OK)
1277                 /* nothing */;
1278
1279         /* Then the data itself.. */
1280         stream.next_in = buf;
1281         stream.avail_in = len;
1282         while (deflate(&stream, Z_FINISH) == Z_OK)
1283                 /* nothing */;
1284         deflateEnd(&stream);
1285         size = stream.total_out;
1286
1287         if (write(fd, compressed, size) != size)
1288                 die("unable to write file");
1289         fchmod(fd, 0444);
1290         close(fd);
1291         free(compressed);
1292
1293         ret = link(tmpfile, filename);
1294         if (ret < 0) {
1295                 ret = errno;
1296
1297                 /*
1298                  * Coda hack - coda doesn't like cross-directory links,
1299                  * so we fall back to a rename, which will mean that it
1300                  * won't be able to check collisions, but that's not a
1301                  * big deal.
1302                  *
1303                  * When this succeeds, we just return 0. We have nothing
1304                  * left to unlink.
1305                  */
1306                 if (ret == EXDEV && !rename(tmpfile, filename))
1307                         return 0;
1308         }
1309         unlink(tmpfile);
1310         if (ret) {
1311                 if (ret != EEXIST) {
1312                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1313                         return -1;
1314                 }
1315                 /* FIXME!!! Collision check here ? */
1316         }
1317
1318         return 0;
1319 }
1320
1321 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1322 {
1323         ssize_t size;
1324         unsigned long objsize;
1325         int posn = 0;
1326         void *map = map_sha1_file_internal(sha1, &objsize);
1327         void *buf = map;
1328         void *temp_obj = NULL;
1329         z_stream stream;
1330
1331         if (!buf) {
1332                 unsigned char *unpacked;
1333                 unsigned long len;
1334                 char type[20];
1335                 char hdr[50];
1336                 int hdrlen;
1337                 // need to unpack and recompress it by itself
1338                 unpacked = read_packed_sha1(sha1, type, &len);
1339
1340                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1341
1342                 /* Set it up */
1343                 memset(&stream, 0, sizeof(stream));
1344                 deflateInit(&stream, Z_BEST_COMPRESSION);
1345                 size = deflateBound(&stream, len + hdrlen);
1346                 temp_obj = buf = xmalloc(size);
1347
1348                 /* Compress it */
1349                 stream.next_out = buf;
1350                 stream.avail_out = size;
1351
1352                 /* First header.. */
1353                 stream.next_in = (void *)hdr;
1354                 stream.avail_in = hdrlen;
1355                 while (deflate(&stream, 0) == Z_OK)
1356                         /* nothing */;
1357
1358                 /* Then the data itself.. */
1359                 stream.next_in = unpacked;
1360                 stream.avail_in = len;
1361                 while (deflate(&stream, Z_FINISH) == Z_OK)
1362                         /* nothing */;
1363                 deflateEnd(&stream);
1364                 free(unpacked);
1365
1366                 objsize = stream.total_out;
1367         }
1368
1369         do {
1370                 size = write(fd, buf + posn, objsize - posn);
1371                 if (size <= 0) {
1372                         if (!size) {
1373                                 fprintf(stderr, "write closed");
1374                         } else {
1375                                 perror("write ");
1376                         }
1377                         return -1;
1378                 }
1379                 posn += size;
1380         } while (posn < objsize);
1381
1382         if (map)
1383                 munmap(map, objsize);
1384         if (temp_obj)
1385                 free(temp_obj);
1386
1387         return 0;
1388 }
1389
1390 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1391                        size_t bufsize, size_t *bufposn)
1392 {
1393         char *filename = sha1_file_name(sha1);
1394
1395         int local;
1396         z_stream stream;
1397         unsigned char real_sha1[20];
1398         unsigned char discard[4096];
1399         int ret;
1400         SHA_CTX c;
1401
1402         local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1403
1404         if (local < 0)
1405                 return error("Couldn't open %s\n", filename);
1406
1407         memset(&stream, 0, sizeof(stream));
1408
1409         inflateInit(&stream);
1410
1411         SHA1_Init(&c);
1412
1413         do {
1414                 ssize_t size;
1415                 if (*bufposn) {
1416                         stream.avail_in = *bufposn;
1417                         stream.next_in = (unsigned char *) buffer;
1418                         do {
1419                                 stream.next_out = discard;
1420                                 stream.avail_out = sizeof(discard);
1421                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1422                                 SHA1_Update(&c, discard, sizeof(discard) -
1423                                             stream.avail_out);
1424                         } while (stream.avail_in && ret == Z_OK);
1425                         write(local, buffer, *bufposn - stream.avail_in);
1426                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1427                                 stream.avail_in);
1428                         *bufposn = stream.avail_in;
1429                         if (ret != Z_OK)
1430                                 break;
1431                 }
1432                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1433                 if (size <= 0) {
1434                         close(local);
1435                         unlink(filename);
1436                         if (!size)
1437                                 return error("Connection closed?");
1438                         perror("Reading from connection");
1439                         return -1;
1440                 }
1441                 *bufposn += size;
1442         } while (1);
1443         inflateEnd(&stream);
1444
1445         close(local);
1446         SHA1_Final(real_sha1, &c);
1447         if (ret != Z_STREAM_END) {
1448                 unlink(filename);
1449                 return error("File %s corrupted", sha1_to_hex(sha1));
1450         }
1451         if (memcmp(sha1, real_sha1, 20)) {
1452                 unlink(filename);
1453                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1454         }
1455
1456         return 0;
1457 }
1458
1459 int has_pack_index(const unsigned char *sha1)
1460 {
1461         struct stat st;
1462         if (stat(sha1_pack_index_name(sha1), &st))
1463                 return 0;
1464         return 1;
1465 }
1466
1467 int has_pack_file(const unsigned char *sha1)
1468 {
1469         struct stat st;
1470         if (stat(sha1_pack_name(sha1), &st))
1471                 return 0;
1472         return 1;
1473 }
1474
1475 int has_sha1_pack(const unsigned char *sha1)
1476 {
1477         struct pack_entry e;
1478         return find_pack_entry(sha1, &e);
1479 }
1480
1481 int has_sha1_file(const unsigned char *sha1)
1482 {
1483         struct stat st;
1484         struct pack_entry e;
1485
1486         if (find_pack_entry(sha1, &e))
1487                 return 1;
1488         return find_sha1_file(sha1, &st) ? 1 : 0;
1489 }
1490
1491 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1492 {
1493         unsigned long size = st->st_size;
1494         void *buf;
1495         int ret;
1496         unsigned char hdr[50];
1497         int hdrlen;
1498
1499         buf = "";
1500         if (size)
1501                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1502         close(fd);
1503         if (buf == MAP_FAILED)
1504                 return -1;
1505
1506         if (!type)
1507                 type = "blob";
1508         if (write_object)
1509                 ret = write_sha1_file(buf, size, type, sha1);
1510         else {
1511                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1512                 ret = 0;
1513         }
1514         if (size)
1515                 munmap(buf, size);
1516         return ret;
1517 }