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;
 287
 288         alt = gitenv(ALTERNATE_DB_ENVIRONMENT);
 289         if (!alt) alt = "";
 290
 291         sprintf(path, "%s/info/alternates", get_object_directory());
 292         if (alt_odb_tail)
 293                 return;
 294         alt_odb_tail = &alt_odb_list;
 295         link_alt_odb_entries(alt, alt + strlen(alt), ':');
 296
 297         fd = open(path, O_RDONLY);
 298         if (fd < 0)
 299                 return;
 300         if (fstat(fd, &st) || (st.st_size == 0)) {
 301                 close(fd);
 302                 return;
 303         }
 304         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 305         close(fd);
 306         if (map == MAP_FAILED)
 307                 return;
 308
 309         link_alt_odb_entries(map, map + st.st_size, '\n');
 310         munmap(map, st.st_size);
 311 }
 312
 313 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 314 {
 315         char *name = sha1_file_name(sha1);
 316         struct alternate_object_database *alt;
 317
 318         if (!stat(name, st))
 319                 return name;
 320         prepare_alt_odb();
 321         for (alt = alt_odb_list; alt; alt = alt->next) {
 322                 name = alt->name;
 323                 fill_sha1_path(name, sha1);
 324                 if (!stat(alt->base, st))
 325                         return alt->base;
 326         }
 327         return NULL;
 328 }
 329
 330 #define PACK_MAX_SZ (1<<26)
 331 static int pack_used_ctr;
 332 static unsigned long pack_mapped;
 333 struct packed_git *packed_git;
 334
 335 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 336                                 void **idx_map_)
 337 {
 338         void *idx_map;
 339         unsigned int *index;
 340         unsigned long idx_size;
 341         int nr, i;
 342         int fd = open(path, O_RDONLY);
 343         struct stat st;
 344         if (fd < 0)
 345                 return -1;
 346         if (fstat(fd, &st)) {
 347                 close(fd);
 348                 return -1;
 349         }
 350         idx_size = st.st_size;
 351         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 352         close(fd);
 353         if (idx_map == MAP_FAILED)
 354                 return -1;
 355
 356         index = idx_map;
 357         *idx_map_ = idx_map;
 358         *idx_size_ = idx_size;
 359
 360         /* check index map */
 361         if (idx_size < 4*256 + 20 + 20)
 362                 return error("index file too small");
 363         nr = 0;
 364         for (i = 0; i < 256; i++) {
 365                 unsigned int n = ntohl(index[i]);
 366                 if (n < nr)
 367                         return error("non-monotonic index");
 368                 nr = n;
 369         }
 370
 371         /*
 372          * Total size:
 373          *  - 256 index entries 4 bytes each
 374          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 375          *  - 20-byte SHA1 of the packfile
 376          *  - 20-byte SHA1 file checksum
 377          */
 378         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 379                 return error("wrong index file size");
 380
 381         return 0;
 382 }
 383
 384 static int unuse_one_packed_git(void)
 385 {
 386         struct packed_git *p, *lru = NULL;
 387
 388         for (p = packed_git; p; p = p->next) {
 389                 if (p->pack_use_cnt || !p->pack_base)
 390                         continue;
 391                 if (!lru || p->pack_last_used < lru->pack_last_used)
 392                         lru = p;
 393         }
 394         if (!lru)
 395                 return 0;
 396         munmap(lru->pack_base, lru->pack_size);
 397         lru->pack_base = NULL;
 398         return 1;
 399 }
 400
 401 void unuse_packed_git(struct packed_git *p)
 402 {
 403         p->pack_use_cnt--;
 404 }
 405
 406 int use_packed_git(struct packed_git *p)
 407 {
 408         if (!p->pack_size) {
 409                 struct stat st;
 410                 // We created the struct before we had the pack
 411                 stat(p->pack_name, &st);
 412                 if (!S_ISREG(st.st_mode))
 413                         die("packfile %s not a regular file", p->pack_name);
 414                 p->pack_size = st.st_size;
 415         }
 416         if (!p->pack_base) {
 417                 int fd;
 418                 struct stat st;
 419                 void *map;
 420
 421                 pack_mapped += p->pack_size;
 422                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 423                         ; /* nothing */
 424                 fd = open(p->pack_name, O_RDONLY);
 425                 if (fd < 0)
 426                         die("packfile %s cannot be opened", p->pack_name);
 427                 if (fstat(fd, &st)) {
 428                         close(fd);
 429                         die("packfile %s cannot be opened", p->pack_name);
 430                 }
 431                 if (st.st_size != p->pack_size)
 432                         die("packfile %s size mismatch.", p->pack_name);
 433                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 434                 close(fd);
 435                 if (map == MAP_FAILED)
 436                         die("packfile %s cannot be mapped.", p->pack_name);
 437                 p->pack_base = map;
 438
 439                 /* Check if the pack file matches with the index file.
 440                  * this is cheap.
 441                  */
 442                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 443                            p->pack_base + p->pack_size - 20, 20)) {
 444
 445                         die("packfile %s does not match index.", p->pack_name);
 446                 }
 447         }
 448         p->pack_last_used = pack_used_ctr++;
 449         p->pack_use_cnt++;
 450         return 0;
 451 }
 452
 453 struct packed_git *add_packed_git(char *path, int path_len)
 454 {
 455         struct stat st;
 456         struct packed_git *p;
 457         unsigned long idx_size;
 458         void *idx_map;
 459
 460         if (check_packed_git_idx(path, &idx_size, &idx_map))
 461                 return NULL;
 462
 463         /* do we have a corresponding .pack file? */
 464         strcpy(path + path_len - 4, ".pack");
 465         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 466                 munmap(idx_map, idx_size);
 467                 return NULL;
 468         }
 469         /* ok, it looks sane as far as we can check without
 470          * actually mapping the pack file.
 471          */
 472         p = xmalloc(sizeof(*p) + path_len + 2);
 473         strcpy(p->pack_name, path);
 474         p->index_size = idx_size;
 475         p->pack_size = st.st_size;
 476         p->index_base = idx_map;
 477         p->next = NULL;
 478         p->pack_base = NULL;
 479         p->pack_last_used = 0;
 480         p->pack_use_cnt = 0;
 481         return p;
 482 }
 483
 484 struct packed_git *parse_pack_index(unsigned char *sha1)
 485 {
 486         char *path = sha1_pack_index_name(sha1);
 487         return parse_pack_index_file(sha1, path);
 488 }
 489
 490 struct packed_git *parse_pack_index_file(unsigned char *sha1, char *idx_path)
 491 {
 492         struct packed_git *p;
 493         unsigned long idx_size;
 494         void *idx_map;
 495         char *path;
 496
 497         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 498                 return NULL;
 499
 500         path = sha1_pack_name(sha1);
 501
 502         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 503         strcpy(p->pack_name, path);
 504         p->index_size = idx_size;
 505         p->pack_size = 0;
 506         p->index_base = idx_map;
 507         p->next = NULL;
 508         p->pack_base = NULL;
 509         p->pack_last_used = 0;
 510         p->pack_use_cnt = 0;
 511         memcpy(p->sha1, sha1, 20);
 512         return p;
 513 }
 514
 515 void install_packed_git(struct packed_git *pack)
 516 {
 517         pack->next = packed_git;
 518         packed_git = pack;
 519 }
 520
 521 static void prepare_packed_git_one(char *objdir)
 522 {
 523         char path[PATH_MAX];
 524         int len;
 525         DIR *dir;
 526         struct dirent *de;
 527
 528         sprintf(path, "%s/pack", objdir);
 529         len = strlen(path);
 530         dir = opendir(path);
 531         if (!dir)
 532                 return;
 533         path[len++] = '/';
 534         while ((de = readdir(dir)) != NULL) {
 535                 int namelen = strlen(de->d_name);
 536                 struct packed_git *p;
 537
 538                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 539                         continue;
 540
 541                 /* we have .idx.  Is it a file we can map? */
 542                 strcpy(path + len, de->d_name);
 543                 p = add_packed_git(path, len + namelen);
 544                 if (!p)
 545                         continue;
 546                 p->next = packed_git;
 547                 packed_git = p;
 548         }
 549         closedir(dir);
 550 }
 551
 552 void prepare_packed_git(void)
 553 {
 554         static int run_once = 0;
 555         struct alternate_object_database *alt;
 556
 557         if (run_once)
 558                 return;
 559         prepare_packed_git_one(get_object_directory());
 560         prepare_alt_odb();
 561         for (alt = alt_odb_list; alt; alt = alt->next) {
 562                 alt->name[0] = 0;
 563                 prepare_packed_git_one(alt->base);
 564         }
 565         run_once = 1;
 566 }
 567
 568 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 569 {
 570         char header[100];
 571         unsigned char real_sha1[20];
 572         SHA_CTX c;
 573
 574         SHA1_Init(&c);
 575         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 576         SHA1_Update(&c, map, size);
 577         SHA1_Final(real_sha1, &c);
 578         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 579 }
 580
 581 static void *map_sha1_file_internal(const unsigned char *sha1,
 582                                     unsigned long *size)
 583 {
 584         struct stat st;
 585         void *map;
 586         int fd;
 587         char *filename = find_sha1_file(sha1, &st);
 588
 589         if (!filename) {
 590                 return NULL;
 591         }
 592
 593         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 594         if (fd < 0) {
 595                 /* See if it works without O_NOATIME */
 596                 switch (sha1_file_open_flag) {
 597                 default:
 598                         fd = open(filename, O_RDONLY);
 599                         if (fd >= 0)
 600                                 break;
 601                 /* Fallthrough */
 602                 case 0:
 603                         return NULL;
 604                 }
 605
 606                 /* If it failed once, it will probably fail again.
 607                  * Stop using O_NOATIME
 608                  */
 609                 sha1_file_open_flag = 0;
 610         }
 611         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 612         close(fd);
 613         if (map == MAP_FAILED)
 614                 return NULL;
 615         *size = st.st_size;
 616         return map;
 617 }
 618
 619 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 620 {
 621         /* Get the data stream */
 622         memset(stream, 0, sizeof(*stream));
 623         stream->next_in = map;
 624         stream->avail_in = mapsize;
 625         stream->next_out = buffer;
 626         stream->avail_out = size;
 627
 628         inflateInit(stream);
 629         return inflate(stream, 0);
 630 }
 631
 632 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 633 {
 634         int bytes = strlen(buffer) + 1;
 635         unsigned char *buf = xmalloc(1+size);
 636
 637         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 638         bytes = stream->total_out - bytes;
 639         if (bytes < size) {
 640                 stream->next_out = buf + bytes;
 641                 stream->avail_out = size - bytes;
 642                 while (inflate(stream, Z_FINISH) == Z_OK)
 643                         /* nothing */;
 644         }
 645         buf[size] = 0;
 646         inflateEnd(stream);
 647         return buf;
 648 }
 649
 650 /*
 651  * We used to just use "sscanf()", but that's actually way
 652  * too permissive for what we want to check. So do an anal
 653  * object header parse by hand.
 654  */
 655 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 656 {
 657         int i;
 658         unsigned long size;
 659
 660         /*
 661          * The type can be at most ten bytes (including the
 662          * terminating '\0' that we add), and is followed by
 663          * a space.
 664          */
 665         i = 10;
 666         for (;;) {
 667                 char c = *hdr++;
 668                 if (c == ' ')
 669                         break;
 670                 if (!--i)
 671                         return -1;
 672                 *type++ = c;
 673         }
 674         *type = 0;
 675
 676         /*
 677          * The length must follow immediately, and be in canonical
 678          * decimal format (ie "010" is not valid).
 679          */
 680         size = *hdr++ - '0';
 681         if (size > 9)
 682                 return -1;
 683         if (size) {
 684                 for (;;) {
 685                         unsigned long c = *hdr - '0';
 686                         if (c > 9)
 687                                 break;
 688                         hdr++;
 689                         size = size * 10 + c;
 690                 }
 691         }
 692         *sizep = size;
 693
 694         /*
 695          * The length must be followed by a zero byte
 696          */
 697         return *hdr ? -1 : 0;
 698 }
 699
 700 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 701 {
 702         int ret;
 703         z_stream stream;
 704         char hdr[8192];
 705
 706         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 707         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 708                 return NULL;
 709
 710         return unpack_sha1_rest(&stream, hdr, *size);
 711 }
 712
 713 /* forward declaration for a mutually recursive function */
 714 static int packed_object_info(struct pack_entry *entry,
 715                               char *type, unsigned long *sizep);
 716
 717 static int packed_delta_info(unsigned char *base_sha1,
 718                              unsigned long delta_size,
 719                              unsigned long left,
 720                              char *type,
 721                              unsigned long *sizep,
 722                              struct packed_git *p)
 723 {
 724         struct pack_entry base_ent;
 725
 726         if (left < 20)
 727                 die("truncated pack file");
 728
 729         /* The base entry _must_ be in the same pack */
 730         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 731                 die("failed to find delta-pack base object %s",
 732                     sha1_to_hex(base_sha1));
 733
 734         /* We choose to only get the type of the base object and
 735          * ignore potentially corrupt pack file that expects the delta
 736          * based on a base with a wrong size.  This saves tons of
 737          * inflate() calls.
 738          */
 739
 740         if (packed_object_info(&base_ent, type, NULL))
 741                 die("cannot get info for delta-pack base");
 742
 743         if (sizep) {
 744                 const unsigned char *data;
 745                 unsigned char delta_head[64];
 746                 unsigned long result_size;
 747                 z_stream stream;
 748                 int st;
 749
 750                 memset(&stream, 0, sizeof(stream));
 751
 752                 data = stream.next_in = base_sha1 + 20;
 753                 stream.avail_in = left - 20;
 754                 stream.next_out = delta_head;
 755                 stream.avail_out = sizeof(delta_head);
 756
 757                 inflateInit(&stream);
 758                 st = inflate(&stream, Z_FINISH);
 759                 inflateEnd(&stream);
 760                 if ((st != Z_STREAM_END) &&
 761                     stream.total_out != sizeof(delta_head))
 762                         die("delta data unpack-initial failed");
 763
 764                 /* Examine the initial part of the delta to figure out
 765                  * the result size.
 766                  */
 767                 data = delta_head;
 768                 get_delta_hdr_size(&data); /* ignore base size */
 769
 770                 /* Read the result size */
 771                 result_size = get_delta_hdr_size(&data);
 772                 *sizep = result_size;
 773         }
 774         return 0;
 775 }
 776
 777 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 778         enum object_type *type, unsigned long *sizep)
 779 {
 780         unsigned shift;
 781         unsigned char *pack, c;
 782         unsigned long size;
 783
 784         if (offset >= p->pack_size)
 785                 die("object offset outside of pack file");
 786
 787         pack =  p->pack_base + offset;
 788         c = *pack++;
 789         offset++;
 790         *type = (c >> 4) & 7;
 791         size = c & 15;
 792         shift = 4;
 793         while (c & 0x80) {
 794                 if (offset >= p->pack_size)
 795                         die("object offset outside of pack file");
 796                 c = *pack++;
 797                 offset++;
 798                 size += (c & 0x7f) << shift;
 799                 shift += 7;
 800         }
 801         *sizep = size;
 802         return offset;
 803 }
 804
 805 void packed_object_info_detail(struct pack_entry *e,
 806                                char *type,
 807                                unsigned long *size,
 808                                unsigned long *store_size,
 809                                int *delta_chain_length,
 810                                unsigned char *base_sha1)
 811 {
 812         struct packed_git *p = e->p;
 813         unsigned long offset, left;
 814         unsigned char *pack;
 815         enum object_type kind;
 816
 817         offset = unpack_object_header(p, e->offset, &kind, size);
 818         pack = p->pack_base + offset;
 819         left = p->pack_size - offset;
 820         if (kind != OBJ_DELTA)
 821                 *delta_chain_length = 0;
 822         else {
 823                 int chain_length = 0;
 824                 memcpy(base_sha1, pack, 20);
 825                 do {
 826                         struct pack_entry base_ent;
 827                         unsigned long junk;
 828
 829                         find_pack_entry_one(pack, &base_ent, p);
 830                         offset = unpack_object_header(p, base_ent.offset,
 831                                                       &kind, &junk);
 832                         pack = p->pack_base + offset;
 833                         chain_length++;
 834                 } while (kind == OBJ_DELTA);
 835                 *delta_chain_length = chain_length;
 836         }
 837         switch (kind) {
 838         case OBJ_COMMIT:
 839                 strcpy(type, "commit");
 840                 break;
 841         case OBJ_TREE:
 842                 strcpy(type, "tree");
 843                 break;
 844         case OBJ_BLOB:
 845                 strcpy(type, "blob");
 846                 break;
 847         case OBJ_TAG:
 848                 strcpy(type, "tag");
 849                 break;
 850         default:
 851                 die("corrupted pack file");
 852         }
 853         *store_size = 0; /* notyet */
 854 }
 855
 856 static int packed_object_info(struct pack_entry *entry,
 857                               char *type, unsigned long *sizep)
 858 {
 859         struct packed_git *p = entry->p;
 860         unsigned long offset, size, left;
 861         unsigned char *pack;
 862         enum object_type kind;
 863         int retval;
 864
 865         if (use_packed_git(p))
 866                 die("cannot map packed file");
 867
 868         offset = unpack_object_header(p, entry->offset, &kind, &size);
 869         pack = p->pack_base + offset;
 870         left = p->pack_size - offset;
 871
 872         switch (kind) {
 873         case OBJ_DELTA:
 874                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 875                 unuse_packed_git(p);
 876                 return retval;
 877         case OBJ_COMMIT:
 878                 strcpy(type, "commit");
 879                 break;
 880         case OBJ_TREE:
 881                 strcpy(type, "tree");
 882                 break;
 883         case OBJ_BLOB:
 884                 strcpy(type, "blob");
 885                 break;
 886         case OBJ_TAG:
 887                 strcpy(type, "tag");
 888                 break;
 889         default:
 890                 die("corrupted pack file");
 891         }
 892         if (sizep)
 893                 *sizep = size;
 894         unuse_packed_git(p);
 895         return 0;
 896 }
 897
 898 /* forward declaration for a mutually recursive function */
 899 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 900
 901 static void *unpack_delta_entry(unsigned char *base_sha1,
 902                                 unsigned long delta_size,
 903                                 unsigned long left,
 904                                 char *type,
 905                                 unsigned long *sizep,
 906                                 struct packed_git *p)
 907 {
 908         struct pack_entry base_ent;
 909         void *data, *delta_data, *result, *base;
 910         unsigned long data_size, result_size, base_size;
 911         z_stream stream;
 912         int st;
 913
 914         if (left < 20)
 915                 die("truncated pack file");
 916         data = base_sha1 + 20;
 917         data_size = left - 20;
 918         delta_data = xmalloc(delta_size);
 919
 920         memset(&stream, 0, sizeof(stream));
 921
 922         stream.next_in = data;
 923         stream.avail_in = data_size;
 924         stream.next_out = delta_data;
 925         stream.avail_out = delta_size;
 926
 927         inflateInit(&stream);
 928         st = inflate(&stream, Z_FINISH);
 929         inflateEnd(&stream);
 930         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 931                 die("delta data unpack failed");
 932
 933         /* The base entry _must_ be in the same pack */
 934         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 935                 die("failed to find delta-pack base object %s",
 936                     sha1_to_hex(base_sha1));
 937         base = unpack_entry_gently(&base_ent, type, &base_size);
 938         if (!base)
 939                 die("failed to read delta-pack base object %s",
 940                     sha1_to_hex(base_sha1));
 941         result = patch_delta(base, base_size,
 942                              delta_data, delta_size,
 943                              &result_size);
 944         if (!result)
 945                 die("failed to apply delta");
 946         free(delta_data);
 947         free(base);
 948         *sizep = result_size;
 949         return result;
 950 }
 951
 952 static void *unpack_non_delta_entry(unsigned char *data,
 953                                     unsigned long size,
 954                                     unsigned long left)
 955 {
 956         int st;
 957         z_stream stream;
 958         unsigned char *buffer;
 959
 960         buffer = xmalloc(size + 1);
 961         buffer[size] = 0;
 962         memset(&stream, 0, sizeof(stream));
 963         stream.next_in = data;
 964         stream.avail_in = left;
 965         stream.next_out = buffer;
 966         stream.avail_out = size;
 967
 968         inflateInit(&stream);
 969         st = inflate(&stream, Z_FINISH);
 970         inflateEnd(&stream);
 971         if ((st != Z_STREAM_END) || stream.total_out != size) {
 972                 free(buffer);
 973                 return NULL;
 974         }
 975
 976         return buffer;
 977 }
 978
 979 static void *unpack_entry(struct pack_entry *entry,
 980                           char *type, unsigned long *sizep)
 981 {
 982         struct packed_git *p = entry->p;
 983         void *retval;
 984
 985         if (use_packed_git(p))
 986                 die("cannot map packed file");
 987         retval = unpack_entry_gently(entry, type, sizep);
 988         unuse_packed_git(p);
 989         if (!retval)
 990                 die("corrupted pack file");
 991         return retval;
 992 }
 993
 994 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 995 void *unpack_entry_gently(struct pack_entry *entry,
 996                           char *type, unsigned long *sizep)
 997 {
 998         struct packed_git *p = entry->p;
 999         unsigned long offset, size, left;
1000         unsigned char *pack;
1001         enum object_type kind;
1002         void *retval;
1003
1004         offset = unpack_object_header(p, entry->offset, &kind, &size);
1005         pack = p->pack_base + offset;
1006         left = p->pack_size - offset;
1007         switch (kind) {
1008         case OBJ_DELTA:
1009                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1010                 return retval;
1011         case OBJ_COMMIT:
1012                 strcpy(type, "commit");
1013                 break;
1014         case OBJ_TREE:
1015                 strcpy(type, "tree");
1016                 break;
1017         case OBJ_BLOB:
1018                 strcpy(type, "blob");
1019                 break;
1020         case OBJ_TAG:
1021                 strcpy(type, "tag");
1022                 break;
1023         default:
1024                 return NULL;
1025         }
1026         *sizep = size;
1027         retval = unpack_non_delta_entry(pack, size, left);
1028         return retval;
1029 }
1030
1031 int num_packed_objects(const struct packed_git *p)
1032 {
1033         /* See check_packed_git_idx() */
1034         return (p->index_size - 20 - 20 - 4*256) / 24;
1035 }
1036
1037 int nth_packed_object_sha1(const struct packed_git *p, int n,
1038                            unsigned char* sha1)
1039 {
1040         void *index = p->index_base + 256;
1041         if (n < 0 || num_packed_objects(p) <= n)
1042                 return -1;
1043         memcpy(sha1, (index + 24 * n + 4), 20);
1044         return 0;
1045 }
1046
1047 int find_pack_entry_one(const unsigned char *sha1,
1048                         struct pack_entry *e, struct packed_git *p)
1049 {
1050         unsigned int *level1_ofs = p->index_base;
1051         int hi = ntohl(level1_ofs[*sha1]);
1052         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1053         void *index = p->index_base + 256;
1054
1055         do {
1056                 int mi = (lo + hi) / 2;
1057                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1058                 if (!cmp) {
1059                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1060                         memcpy(e->sha1, sha1, 20);
1061                         e->p = p;
1062                         return 1;
1063                 }
1064                 if (cmp > 0)
1065                         hi = mi;
1066                 else
1067                         lo = mi+1;
1068         } while (lo < hi);
1069         return 0;
1070 }
1071
1072 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1073 {
1074         struct packed_git *p;
1075         prepare_packed_git();
1076
1077         for (p = packed_git; p; p = p->next) {
1078                 if (find_pack_entry_one(sha1, e, p))
1079                         return 1;
1080         }
1081         return 0;
1082 }
1083
1084 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1085                                   struct packed_git *packs)
1086 {
1087         struct packed_git *p;
1088         struct pack_entry e;
1089
1090         for (p = packs; p; p = p->next) {
1091                 if (find_pack_entry_one(sha1, &e, p))
1092                         return p;
1093         }
1094         return NULL;
1095
1096 }
1097
1098 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1099 {
1100         int status;
1101         unsigned long mapsize, size;
1102         void *map;
1103         z_stream stream;
1104         char hdr[128];
1105
1106         map = map_sha1_file_internal(sha1, &mapsize);
1107         if (!map) {
1108                 struct pack_entry e;
1109
1110                 if (!find_pack_entry(sha1, &e))
1111                         return error("unable to find %s", sha1_to_hex(sha1));
1112                 return packed_object_info(&e, type, sizep);
1113         }
1114         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1115                 status = error("unable to unpack %s header",
1116                                sha1_to_hex(sha1));
1117         if (parse_sha1_header(hdr, type, &size) < 0)
1118                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1119         else {
1120                 status = 0;
1121                 if (sizep)
1122                         *sizep = size;
1123         }
1124         inflateEnd(&stream);
1125         munmap(map, mapsize);
1126         return status;
1127 }
1128
1129 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1130 {
1131         struct pack_entry e;
1132
1133         if (!find_pack_entry(sha1, &e)) {
1134                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1135                 return NULL;
1136         }
1137         return unpack_entry(&e, type, size);
1138 }
1139
1140 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1141 {
1142         unsigned long mapsize;
1143         void *map, *buf;
1144         struct pack_entry e;
1145
1146         if (find_pack_entry(sha1, &e))
1147                 return read_packed_sha1(sha1, type, size);
1148         map = map_sha1_file_internal(sha1, &mapsize);
1149         if (map) {
1150                 buf = unpack_sha1_file(map, mapsize, type, size);
1151                 munmap(map, mapsize);
1152                 return buf;
1153         }
1154         return NULL;
1155 }
1156
1157 void *read_object_with_reference(const unsigned char *sha1,
1158                                  const char *required_type,
1159                                  unsigned long *size,
1160                                  unsigned char *actual_sha1_return)
1161 {
1162         char type[20];
1163         void *buffer;
1164         unsigned long isize;
1165         unsigned char actual_sha1[20];
1166
1167         memcpy(actual_sha1, sha1, 20);
1168         while (1) {
1169                 int ref_length = -1;
1170                 const char *ref_type = NULL;
1171
1172                 buffer = read_sha1_file(actual_sha1, type, &isize);
1173                 if (!buffer)
1174                         return NULL;
1175                 if (!strcmp(type, required_type)) {
1176                         *size = isize;
1177                         if (actual_sha1_return)
1178                                 memcpy(actual_sha1_return, actual_sha1, 20);
1179                         return buffer;
1180                 }
1181                 /* Handle references */
1182                 else if (!strcmp(type, "commit"))
1183                         ref_type = "tree ";
1184                 else if (!strcmp(type, "tag"))
1185                         ref_type = "object ";
1186                 else {
1187                         free(buffer);
1188                         return NULL;
1189                 }
1190                 ref_length = strlen(ref_type);
1191
1192                 if (memcmp(buffer, ref_type, ref_length) ||
1193                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1194                         free(buffer);
1195                         return NULL;
1196                 }
1197                 free(buffer);
1198                 /* Now we have the ID of the referred-to object in
1199                  * actual_sha1.  Check again. */
1200         }
1201 }
1202
1203 char *write_sha1_file_prepare(void *buf,
1204                               unsigned long len,
1205                               const char *type,
1206                               unsigned char *sha1,
1207                               unsigned char *hdr,
1208                               int *hdrlen)
1209 {
1210         SHA_CTX c;
1211
1212         /* Generate the header */
1213         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1214
1215         /* Sha1.. */
1216         SHA1_Init(&c);
1217         SHA1_Update(&c, hdr, *hdrlen);
1218         SHA1_Update(&c, buf, len);
1219         SHA1_Final(sha1, &c);
1220
1221         return sha1_file_name(sha1);
1222 }
1223
1224 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1225 {
1226         int size;
1227         unsigned char *compressed;
1228         z_stream stream;
1229         unsigned char sha1[20];
1230         char *filename;
1231         static char tmpfile[PATH_MAX];
1232         unsigned char hdr[50];
1233         int fd, hdrlen, ret;
1234
1235         /* Normally if we have it in the pack then we do not bother writing
1236          * it out into .git/objects/??/?{38} file.
1237          */
1238         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1239         if (returnsha1)
1240                 memcpy(returnsha1, sha1, 20);
1241         if (has_sha1_file(sha1))
1242                 return 0;
1243         fd = open(filename, O_RDONLY);
1244         if (fd >= 0) {
1245                 /*
1246                  * FIXME!!! We might do collision checking here, but we'd
1247                  * need to uncompress the old file and check it. Later.
1248                  */
1249                 close(fd);
1250                 return 0;
1251         }
1252
1253         if (errno != ENOENT) {
1254                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1255                 return -1;
1256         }
1257
1258         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1259
1260         fd = mkstemp(tmpfile);
1261         if (fd < 0) {
1262                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1263                 return -1;
1264         }
1265
1266         /* Set it up */
1267         memset(&stream, 0, sizeof(stream));
1268         deflateInit(&stream, Z_BEST_COMPRESSION);
1269         size = deflateBound(&stream, len+hdrlen);
1270         compressed = xmalloc(size);
1271
1272         /* Compress it */
1273         stream.next_out = compressed;
1274         stream.avail_out = size;
1275
1276         /* First header.. */
1277         stream.next_in = hdr;
1278         stream.avail_in = hdrlen;
1279         while (deflate(&stream, 0) == Z_OK)
1280                 /* nothing */;
1281
1282         /* Then the data itself.. */
1283         stream.next_in = buf;
1284         stream.avail_in = len;
1285         while (deflate(&stream, Z_FINISH) == Z_OK)
1286                 /* nothing */;
1287         deflateEnd(&stream);
1288         size = stream.total_out;
1289
1290         if (write(fd, compressed, size) != size)
1291                 die("unable to write file");
1292         fchmod(fd, 0444);
1293         close(fd);
1294         free(compressed);
1295
1296         ret = link(tmpfile, filename);
1297         if (ret < 0) {
1298                 ret = errno;
1299
1300                 /*
1301                  * Coda hack - coda doesn't like cross-directory links,
1302                  * so we fall back to a rename, which will mean that it
1303                  * won't be able to check collisions, but that's not a
1304                  * big deal.
1305                  *
1306                  * When this succeeds, we just return 0. We have nothing
1307                  * left to unlink.
1308                  */
1309                 if (ret == EXDEV && !rename(tmpfile, filename))
1310                         return 0;
1311         }
1312         unlink(tmpfile);
1313         if (ret) {
1314                 if (ret != EEXIST) {
1315                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1316                         return -1;
1317                 }
1318                 /* FIXME!!! Collision check here ? */
1319         }
1320
1321         return 0;
1322 }
1323
1324 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1325 {
1326         ssize_t size;
1327         unsigned long objsize;
1328         int posn = 0;
1329         void *map = map_sha1_file_internal(sha1, &objsize);
1330         void *buf = map;
1331         void *temp_obj = NULL;
1332         z_stream stream;
1333
1334         if (!buf) {
1335                 unsigned char *unpacked;
1336                 unsigned long len;
1337                 char type[20];
1338                 char hdr[50];
1339                 int hdrlen;
1340                 // need to unpack and recompress it by itself
1341                 unpacked = read_packed_sha1(sha1, type, &len);
1342
1343                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1344
1345                 /* Set it up */
1346                 memset(&stream, 0, sizeof(stream));
1347                 deflateInit(&stream, Z_BEST_COMPRESSION);
1348                 size = deflateBound(&stream, len + hdrlen);
1349                 temp_obj = buf = xmalloc(size);
1350
1351                 /* Compress it */
1352                 stream.next_out = buf;
1353                 stream.avail_out = size;
1354
1355                 /* First header.. */
1356                 stream.next_in = (void *)hdr;
1357                 stream.avail_in = hdrlen;
1358                 while (deflate(&stream, 0) == Z_OK)
1359                         /* nothing */;
1360
1361                 /* Then the data itself.. */
1362                 stream.next_in = unpacked;
1363                 stream.avail_in = len;
1364                 while (deflate(&stream, Z_FINISH) == Z_OK)
1365                         /* nothing */;
1366                 deflateEnd(&stream);
1367                 free(unpacked);
1368
1369                 objsize = stream.total_out;
1370         }
1371
1372         do {
1373                 size = write(fd, buf + posn, objsize - posn);
1374                 if (size <= 0) {
1375                         if (!size) {
1376                                 fprintf(stderr, "write closed");
1377                         } else {
1378                                 perror("write ");
1379                         }
1380                         return -1;
1381                 }
1382                 posn += size;
1383         } while (posn < objsize);
1384
1385         if (map)
1386                 munmap(map, objsize);
1387         if (temp_obj)
1388                 free(temp_obj);
1389
1390         return 0;
1391 }
1392
1393 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1394                        size_t bufsize, size_t *bufposn)
1395 {
1396         char *filename = sha1_file_name(sha1);
1397
1398         int local;
1399         z_stream stream;
1400         unsigned char real_sha1[20];
1401         unsigned char discard[4096];
1402         int ret;
1403         SHA_CTX c;
1404
1405         local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);
1406
1407         if (local < 0)
1408                 return error("Couldn't open %s\n", filename);
1409
1410         memset(&stream, 0, sizeof(stream));
1411
1412         inflateInit(&stream);
1413
1414         SHA1_Init(&c);
1415
1416         do {
1417                 ssize_t size;
1418                 if (*bufposn) {
1419                         stream.avail_in = *bufposn;
1420                         stream.next_in = (unsigned char *) buffer;
1421                         do {
1422                                 stream.next_out = discard;
1423                                 stream.avail_out = sizeof(discard);
1424                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1425                                 SHA1_Update(&c, discard, sizeof(discard) -
1426                                             stream.avail_out);
1427                         } while (stream.avail_in && ret == Z_OK);
1428                         write(local, buffer, *bufposn - stream.avail_in);
1429                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1430                                 stream.avail_in);
1431                         *bufposn = stream.avail_in;
1432                         if (ret != Z_OK)
1433                                 break;
1434                 }
1435                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1436                 if (size <= 0) {
1437                         close(local);
1438                         unlink(filename);
1439                         if (!size)
1440                                 return error("Connection closed?");
1441                         perror("Reading from connection");
1442                         return -1;
1443                 }
1444                 *bufposn += size;
1445         } while (1);
1446         inflateEnd(&stream);
1447
1448         close(local);
1449         SHA1_Final(real_sha1, &c);
1450         if (ret != Z_STREAM_END) {
1451                 unlink(filename);
1452                 return error("File %s corrupted", sha1_to_hex(sha1));
1453         }
1454         if (memcmp(sha1, real_sha1, 20)) {
1455                 unlink(filename);
1456                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1457         }
1458
1459         return 0;
1460 }
1461
1462 int has_pack_index(const unsigned char *sha1)
1463 {
1464         struct stat st;
1465         if (stat(sha1_pack_index_name(sha1), &st))
1466                 return 0;
1467         return 1;
1468 }
1469
1470 int has_pack_file(const unsigned char *sha1)
1471 {
1472         struct stat st;
1473         if (stat(sha1_pack_name(sha1), &st))
1474                 return 0;
1475         return 1;
1476 }
1477
1478 int has_sha1_pack(const unsigned char *sha1)
1479 {
1480         struct pack_entry e;
1481         return find_pack_entry(sha1, &e);
1482 }
1483
1484 int has_sha1_file(const unsigned char *sha1)
1485 {
1486         struct stat st;
1487         struct pack_entry e;
1488
1489         if (find_pack_entry(sha1, &e))
1490                 return 1;
1491         return find_sha1_file(sha1, &st) ? 1 : 0;
1492 }
1493
1494 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1495 {
1496         unsigned long size = st->st_size;
1497         void *buf;
1498         int ret;
1499         unsigned char hdr[50];
1500         int hdrlen;
1501
1502         buf = "";
1503         if (size)
1504                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1505         close(fd);
1506         if (buf == MAP_FAILED)
1507                 return -1;
1508
1509         if (!type)
1510                 type = "blob";
1511         if (write_object)
1512                 ret = write_sha1_file(buf, size, type, sha1);
1513         else {
1514                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1515                 ret = 0;
1516         }
1517         if (size)
1518                 munmap(buf, size);
1519         return ret;
1520 }