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 const unsigned char null_sha1[20] = { 0, };
  24
  25 static unsigned int sha1_file_open_flag = O_NOATIME;
  26
  27 static unsigned hexval(char c)
  28 {
  29         if (c >= '0' && c <= '9')
  30                 return c - '0';
  31         if (c >= 'a' && c <= 'f')
  32                 return c - 'a' + 10;
  33         if (c >= 'A' && c <= 'F')
  34                 return c - 'A' + 10;
  35         return ~0;
  36 }
  37
  38 int get_sha1_hex(const char *hex, unsigned char *sha1)
  39 {
  40         int i;
  41         for (i = 0; i < 20; i++) {
  42                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  43                 if (val & ~0xff)
  44                         return -1;
  45                 *sha1++ = val;
  46                 hex += 2;
  47         }
  48         return 0;
  49 }
  50
  51 int safe_create_leading_directories(char *path)
  52 {
  53         char *pos = path;
  54         if (*pos == '/')
  55                 pos++;
  56
  57         while (pos) {
  58                 pos = strchr(pos, '/');
  59                 if (!pos)
  60                         break;
  61                 *pos = 0;
  62                 if (mkdir(path, 0777) < 0)
  63                         if (errno != EEXIST) {
  64                                 *pos = '/';
  65                                 return -1;
  66                         }
  67                 *pos++ = '/';
  68         }
  69         return 0;
  70 }
  71
  72 char * sha1_to_hex(const unsigned char *sha1)
  73 {
  74         static char buffer[50];
  75         static const char hex[] = "0123456789abcdef";
  76         char *buf = buffer;
  77         int i;
  78
  79         for (i = 0; i < 20; i++) {
  80                 unsigned int val = *sha1++;
  81                 *buf++ = hex[val >> 4];
  82                 *buf++ = hex[val & 0xf];
  83         }
  84         return buffer;
  85 }
  86
  87 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
  88 {
  89         int i;
  90         for (i = 0; i < 20; i++) {
  91                 static char hex[] = "0123456789abcdef";
  92                 unsigned int val = sha1[i];
  93                 char *pos = pathbuf + i*2 + (i > 0);
  94                 *pos++ = hex[val >> 4];
  95                 *pos = hex[val & 0xf];
  96         }
  97 }
  98
  99 /*
 100  * NOTE! This returns a statically allocated buffer, so you have to be
 101  * careful about using it. Do a "strdup()" if you need to save the
 102  * filename.
 103  *
 104  * Also note that this returns the location for creating.  Reading
 105  * SHA1 file can happen from any alternate directory listed in the
 106  * DB_ENVIRONMENT environment variable if it is not found in
 107  * the primary object database.
 108  */
 109 char *sha1_file_name(const unsigned char *sha1)
 110 {
 111         static char *name, *base;
 112
 113         if (!base) {
 114                 const char *sha1_file_directory = get_object_directory();
 115                 int len = strlen(sha1_file_directory);
 116                 base = xmalloc(len + 60);
 117                 memcpy(base, sha1_file_directory, len);
 118                 memset(base+len, 0, 60);
 119                 base[len] = '/';
 120                 base[len+3] = '/';
 121                 name = base + len + 1;
 122         }
 123         fill_sha1_path(name, sha1);
 124         return base;
 125 }
 126
 127 char *sha1_pack_name(const unsigned char *sha1)
 128 {
 129         static const char hex[] = "0123456789abcdef";
 130         static char *name, *base, *buf;
 131         int i;
 132
 133         if (!base) {
 134                 const char *sha1_file_directory = get_object_directory();
 135                 int len = strlen(sha1_file_directory);
 136                 base = xmalloc(len + 60);
 137                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 138                 name = base + len + 11;
 139         }
 140
 141         buf = name;
 142
 143         for (i = 0; i < 20; i++) {
 144                 unsigned int val = *sha1++;
 145                 *buf++ = hex[val >> 4];
 146                 *buf++ = hex[val & 0xf];
 147         }
 148
 149         return base;
 150 }
 151
 152 char *sha1_pack_index_name(const unsigned char *sha1)
 153 {
 154         static const char hex[] = "0123456789abcdef";
 155         static char *name, *base, *buf;
 156         int i;
 157
 158         if (!base) {
 159                 const char *sha1_file_directory = get_object_directory();
 160                 int len = strlen(sha1_file_directory);
 161                 base = xmalloc(len + 60);
 162                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 163                 name = base + len + 11;
 164         }
 165
 166         buf = name;
 167
 168         for (i = 0; i < 20; i++) {
 169                 unsigned int val = *sha1++;
 170                 *buf++ = hex[val >> 4];
 171                 *buf++ = hex[val & 0xf];
 172         }
 173
 174         return base;
 175 }
 176
 177 struct alternate_object_database *alt_odb_list;
 178 static struct alternate_object_database **alt_odb_tail;
 179
 180 /*
 181  * Prepare alternate object database registry.
 182  *
 183  * The variable alt_odb_list points at the list of struct
 184  * alternate_object_database.  The elements on this list come from
 185  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 186  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 187  * whose contents is exactly in the same format as that environment
 188  * variable.  Its base points at a statically allocated buffer that
 189  * contains "/the/directory/corresponding/to/.git/objects/...", while
 190  * its name points just after the slash at the end of ".git/objects/"
 191  * in the example above, and has enough space to hold 40-byte hex
 192  * SHA1, an extra slash for the first level indirection, and the
 193  * terminating NUL.
 194  */
 195 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 196                                  const char *relative_base)
 197 {
 198         const char *cp, *last;
 199         struct alternate_object_database *ent;
 200         int base_len = -1;
 201
 202         last = alt;
 203         while (last < ep) {
 204                 cp = last;
 205                 if (cp < ep && *cp == '#') {
 206                         while (cp < ep && *cp != sep)
 207                                 cp++;
 208                         last = cp + 1;
 209                         continue;
 210                 }
 211                 for ( ; cp < ep && *cp != sep; cp++)
 212                         ;
 213                 if (last != cp) {
 214                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 215                         int pfxlen = cp - last;
 216                         int entlen = pfxlen + 43;
 217
 218                         if (*last != '/' && relative_base) {
 219                                 /* Relative alt-odb */
 220                                 if (base_len < 0)
 221                                         base_len = strlen(relative_base) + 1;
 222                                 entlen += base_len;
 223                                 pfxlen += base_len;
 224                         }
 225                         ent = xmalloc(sizeof(*ent) + entlen);
 226                         *alt_odb_tail = ent;
 227                         alt_odb_tail = &(ent->next);
 228                         ent->next = NULL;
 229                         if (*last != '/' && relative_base) {
 230                                 memcpy(ent->base, relative_base, base_len - 1);
 231                                 ent->base[base_len - 1] = '/';
 232                                 memcpy(ent->base + base_len,
 233                                        last, cp - last);
 234                         }
 235                         else
 236                                 memcpy(ent->base, last, pfxlen);
 237                         ent->name = ent->base + pfxlen + 1;
 238                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 239                         ent->base[entlen-1] = 0;
 240                 }
 241                 while (cp < ep && *cp == sep)
 242                         cp++;
 243                 last = cp;
 244         }
 245 }
 246
 247 void prepare_alt_odb(void)
 248 {
 249         char path[PATH_MAX];
 250         char *map;
 251         int fd;
 252         struct stat st;
 253         char *alt;
 254
 255         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 256         if (!alt) alt = "";
 257
 258         if (alt_odb_tail)
 259                 return;
 260         alt_odb_tail = &alt_odb_list;
 261         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 262
 263         sprintf(path, "%s/info/alternates", get_object_directory());
 264         fd = open(path, O_RDONLY);
 265         if (fd < 0)
 266                 return;
 267         if (fstat(fd, &st) || (st.st_size == 0)) {
 268                 close(fd);
 269                 return;
 270         }
 271         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 272         close(fd);
 273         if (map == MAP_FAILED)
 274                 return;
 275
 276         link_alt_odb_entries(map, map + st.st_size, '\n',
 277                              get_object_directory());
 278         munmap(map, st.st_size);
 279 }
 280
 281 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 282 {
 283         char *name = sha1_file_name(sha1);
 284         struct alternate_object_database *alt;
 285
 286         if (!stat(name, st))
 287                 return name;
 288         prepare_alt_odb();
 289         for (alt = alt_odb_list; alt; alt = alt->next) {
 290                 name = alt->name;
 291                 fill_sha1_path(name, sha1);
 292                 if (!stat(alt->base, st))
 293                         return alt->base;
 294         }
 295         return NULL;
 296 }
 297
 298 #define PACK_MAX_SZ (1<<26)
 299 static int pack_used_ctr;
 300 static unsigned long pack_mapped;
 301 struct packed_git *packed_git;
 302
 303 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 304                                 void **idx_map_)
 305 {
 306         void *idx_map;
 307         unsigned int *index;
 308         unsigned long idx_size;
 309         int nr, i;
 310         int fd = open(path, O_RDONLY);
 311         struct stat st;
 312         if (fd < 0)
 313                 return -1;
 314         if (fstat(fd, &st)) {
 315                 close(fd);
 316                 return -1;
 317         }
 318         idx_size = st.st_size;
 319         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 320         close(fd);
 321         if (idx_map == MAP_FAILED)
 322                 return -1;
 323
 324         index = idx_map;
 325         *idx_map_ = idx_map;
 326         *idx_size_ = idx_size;
 327
 328         /* check index map */
 329         if (idx_size < 4*256 + 20 + 20)
 330                 return error("index file too small");
 331         nr = 0;
 332         for (i = 0; i < 256; i++) {
 333                 unsigned int n = ntohl(index[i]);
 334                 if (n < nr)
 335                         return error("non-monotonic index");
 336                 nr = n;
 337         }
 338
 339         /*
 340          * Total size:
 341          *  - 256 index entries 4 bytes each
 342          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 343          *  - 20-byte SHA1 of the packfile
 344          *  - 20-byte SHA1 file checksum
 345          */
 346         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 347                 return error("wrong index file size");
 348
 349         return 0;
 350 }
 351
 352 static int unuse_one_packed_git(void)
 353 {
 354         struct packed_git *p, *lru = NULL;
 355
 356         for (p = packed_git; p; p = p->next) {
 357                 if (p->pack_use_cnt || !p->pack_base)
 358                         continue;
 359                 if (!lru || p->pack_last_used < lru->pack_last_used)
 360                         lru = p;
 361         }
 362         if (!lru)
 363                 return 0;
 364         munmap(lru->pack_base, lru->pack_size);
 365         lru->pack_base = NULL;
 366         return 1;
 367 }
 368
 369 void unuse_packed_git(struct packed_git *p)
 370 {
 371         p->pack_use_cnt--;
 372 }
 373
 374 int use_packed_git(struct packed_git *p)
 375 {
 376         if (!p->pack_size) {
 377                 struct stat st;
 378                 // We created the struct before we had the pack
 379                 stat(p->pack_name, &st);
 380                 if (!S_ISREG(st.st_mode))
 381                         die("packfile %s not a regular file", p->pack_name);
 382                 p->pack_size = st.st_size;
 383         }
 384         if (!p->pack_base) {
 385                 int fd;
 386                 struct stat st;
 387                 void *map;
 388
 389                 pack_mapped += p->pack_size;
 390                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 391                         ; /* nothing */
 392                 fd = open(p->pack_name, O_RDONLY);
 393                 if (fd < 0)
 394                         die("packfile %s cannot be opened", p->pack_name);
 395                 if (fstat(fd, &st)) {
 396                         close(fd);
 397                         die("packfile %s cannot be opened", p->pack_name);
 398                 }
 399                 if (st.st_size != p->pack_size)
 400                         die("packfile %s size mismatch.", p->pack_name);
 401                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 402                 close(fd);
 403                 if (map == MAP_FAILED)
 404                         die("packfile %s cannot be mapped.", p->pack_name);
 405                 p->pack_base = map;
 406
 407                 /* Check if the pack file matches with the index file.
 408                  * this is cheap.
 409                  */
 410                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 411                            p->pack_base + p->pack_size - 20, 20)) {
 412
 413                         die("packfile %s does not match index.", p->pack_name);
 414                 }
 415         }
 416         p->pack_last_used = pack_used_ctr++;
 417         p->pack_use_cnt++;
 418         return 0;
 419 }
 420
 421 struct packed_git *add_packed_git(char *path, int path_len, int local)
 422 {
 423         struct stat st;
 424         struct packed_git *p;
 425         unsigned long idx_size;
 426         void *idx_map;
 427
 428         if (check_packed_git_idx(path, &idx_size, &idx_map))
 429                 return NULL;
 430
 431         /* do we have a corresponding .pack file? */
 432         strcpy(path + path_len - 4, ".pack");
 433         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 434                 munmap(idx_map, idx_size);
 435                 return NULL;
 436         }
 437         /* ok, it looks sane as far as we can check without
 438          * actually mapping the pack file.
 439          */
 440         p = xmalloc(sizeof(*p) + path_len + 2);
 441         strcpy(p->pack_name, path);
 442         p->index_size = idx_size;
 443         p->pack_size = st.st_size;
 444         p->index_base = idx_map;
 445         p->next = NULL;
 446         p->pack_base = NULL;
 447         p->pack_last_used = 0;
 448         p->pack_use_cnt = 0;
 449         p->pack_local = local;
 450         return p;
 451 }
 452
 453 struct packed_git *parse_pack_index(unsigned char *sha1)
 454 {
 455         char *path = sha1_pack_index_name(sha1);
 456         return parse_pack_index_file(sha1, path);
 457 }
 458
 459 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 460 {
 461         struct packed_git *p;
 462         unsigned long idx_size;
 463         void *idx_map;
 464         char *path;
 465
 466         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 467                 return NULL;
 468
 469         path = sha1_pack_name(sha1);
 470
 471         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 472         strcpy(p->pack_name, path);
 473         p->index_size = idx_size;
 474         p->pack_size = 0;
 475         p->index_base = idx_map;
 476         p->next = NULL;
 477         p->pack_base = NULL;
 478         p->pack_last_used = 0;
 479         p->pack_use_cnt = 0;
 480         memcpy(p->sha1, sha1, 20);
 481         return p;
 482 }
 483
 484 void install_packed_git(struct packed_git *pack)
 485 {
 486         pack->next = packed_git;
 487         packed_git = pack;
 488 }
 489
 490 static void prepare_packed_git_one(char *objdir, int local)
 491 {
 492         char path[PATH_MAX];
 493         int len;
 494         DIR *dir;
 495         struct dirent *de;
 496
 497         sprintf(path, "%s/pack", objdir);
 498         len = strlen(path);
 499         dir = opendir(path);
 500         if (!dir)
 501                 return;
 502         path[len++] = '/';
 503         while ((de = readdir(dir)) != NULL) {
 504                 int namelen = strlen(de->d_name);
 505                 struct packed_git *p;
 506
 507                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 508                         continue;
 509
 510                 /* we have .idx.  Is it a file we can map? */
 511                 strcpy(path + len, de->d_name);
 512                 p = add_packed_git(path, len + namelen, local);
 513                 if (!p)
 514                         continue;
 515                 p->next = packed_git;
 516                 packed_git = p;
 517         }
 518         closedir(dir);
 519 }
 520
 521 void prepare_packed_git(void)
 522 {
 523         static int run_once = 0;
 524         struct alternate_object_database *alt;
 525
 526         if (run_once)
 527                 return;
 528         prepare_packed_git_one(get_object_directory(), 1);
 529         prepare_alt_odb();
 530         for (alt = alt_odb_list; alt; alt = alt->next) {
 531                 alt->name[0] = 0;
 532                 prepare_packed_git_one(alt->base, 0);
 533         }
 534         run_once = 1;
 535 }
 536
 537 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 538 {
 539         char header[100];
 540         unsigned char real_sha1[20];
 541         SHA_CTX c;
 542
 543         SHA1_Init(&c);
 544         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 545         SHA1_Update(&c, map, size);
 546         SHA1_Final(real_sha1, &c);
 547         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 548 }
 549
 550 static void *map_sha1_file_internal(const unsigned char *sha1,
 551                                     unsigned long *size)
 552 {
 553         struct stat st;
 554         void *map;
 555         int fd;
 556         char *filename = find_sha1_file(sha1, &st);
 557
 558         if (!filename) {
 559                 return NULL;
 560         }
 561
 562         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 563         if (fd < 0) {
 564                 /* See if it works without O_NOATIME */
 565                 switch (sha1_file_open_flag) {
 566                 default:
 567                         fd = open(filename, O_RDONLY);
 568                         if (fd >= 0)
 569                                 break;
 570                 /* Fallthrough */
 571                 case 0:
 572                         return NULL;
 573                 }
 574
 575                 /* If it failed once, it will probably fail again.
 576                  * Stop using O_NOATIME
 577                  */
 578                 sha1_file_open_flag = 0;
 579         }
 580         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 581         close(fd);
 582         if (map == MAP_FAILED)
 583                 return NULL;
 584         *size = st.st_size;
 585         return map;
 586 }
 587
 588 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 589 {
 590         /* Get the data stream */
 591         memset(stream, 0, sizeof(*stream));
 592         stream->next_in = map;
 593         stream->avail_in = mapsize;
 594         stream->next_out = buffer;
 595         stream->avail_out = size;
 596
 597         inflateInit(stream);
 598         return inflate(stream, 0);
 599 }
 600
 601 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 602 {
 603         int bytes = strlen(buffer) + 1;
 604         unsigned char *buf = xmalloc(1+size);
 605
 606         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 607         bytes = stream->total_out - bytes;
 608         if (bytes < size) {
 609                 stream->next_out = buf + bytes;
 610                 stream->avail_out = size - bytes;
 611                 while (inflate(stream, Z_FINISH) == Z_OK)
 612                         /* nothing */;
 613         }
 614         buf[size] = 0;
 615         inflateEnd(stream);
 616         return buf;
 617 }
 618
 619 /*
 620  * We used to just use "sscanf()", but that's actually way
 621  * too permissive for what we want to check. So do an anal
 622  * object header parse by hand.
 623  */
 624 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 625 {
 626         int i;
 627         unsigned long size;
 628
 629         /*
 630          * The type can be at most ten bytes (including the
 631          * terminating '\0' that we add), and is followed by
 632          * a space.
 633          */
 634         i = 10;
 635         for (;;) {
 636                 char c = *hdr++;
 637                 if (c == ' ')
 638                         break;
 639                 if (!--i)
 640                         return -1;
 641                 *type++ = c;
 642         }
 643         *type = 0;
 644
 645         /*
 646          * The length must follow immediately, and be in canonical
 647          * decimal format (ie "010" is not valid).
 648          */
 649         size = *hdr++ - '0';
 650         if (size > 9)
 651                 return -1;
 652         if (size) {
 653                 for (;;) {
 654                         unsigned long c = *hdr - '0';
 655                         if (c > 9)
 656                                 break;
 657                         hdr++;
 658                         size = size * 10 + c;
 659                 }
 660         }
 661         *sizep = size;
 662
 663         /*
 664          * The length must be followed by a zero byte
 665          */
 666         return *hdr ? -1 : 0;
 667 }
 668
 669 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 670 {
 671         int ret;
 672         z_stream stream;
 673         char hdr[8192];
 674
 675         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 676         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 677                 return NULL;
 678
 679         return unpack_sha1_rest(&stream, hdr, *size);
 680 }
 681
 682 /* forward declaration for a mutually recursive function */
 683 static int packed_object_info(struct pack_entry *entry,
 684                               char *type, unsigned long *sizep);
 685
 686 static int packed_delta_info(unsigned char *base_sha1,
 687                              unsigned long delta_size,
 688                              unsigned long left,
 689                              char *type,
 690                              unsigned long *sizep,
 691                              struct packed_git *p)
 692 {
 693         struct pack_entry base_ent;
 694
 695         if (left < 20)
 696                 die("truncated pack file");
 697
 698         /* The base entry _must_ be in the same pack */
 699         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 700                 die("failed to find delta-pack base object %s",
 701                     sha1_to_hex(base_sha1));
 702
 703         /* We choose to only get the type of the base object and
 704          * ignore potentially corrupt pack file that expects the delta
 705          * based on a base with a wrong size.  This saves tons of
 706          * inflate() calls.
 707          */
 708
 709         if (packed_object_info(&base_ent, type, NULL))
 710                 die("cannot get info for delta-pack base");
 711
 712         if (sizep) {
 713                 const unsigned char *data;
 714                 unsigned char delta_head[64];
 715                 unsigned long result_size;
 716                 z_stream stream;
 717                 int st;
 718
 719                 memset(&stream, 0, sizeof(stream));
 720
 721                 data = stream.next_in = base_sha1 + 20;
 722                 stream.avail_in = left - 20;
 723                 stream.next_out = delta_head;
 724                 stream.avail_out = sizeof(delta_head);
 725
 726                 inflateInit(&stream);
 727                 st = inflate(&stream, Z_FINISH);
 728                 inflateEnd(&stream);
 729                 if ((st != Z_STREAM_END) &&
 730                     stream.total_out != sizeof(delta_head))
 731                         die("delta data unpack-initial failed");
 732
 733                 /* Examine the initial part of the delta to figure out
 734                  * the result size.
 735                  */
 736                 data = delta_head;
 737                 get_delta_hdr_size(&data); /* ignore base size */
 738
 739                 /* Read the result size */
 740                 result_size = get_delta_hdr_size(&data);
 741                 *sizep = result_size;
 742         }
 743         return 0;
 744 }
 745
 746 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 747         enum object_type *type, unsigned long *sizep)
 748 {
 749         unsigned shift;
 750         unsigned char *pack, c;
 751         unsigned long size;
 752
 753         if (offset >= p->pack_size)
 754                 die("object offset outside of pack file");
 755
 756         pack =  p->pack_base + offset;
 757         c = *pack++;
 758         offset++;
 759         *type = (c >> 4) & 7;
 760         size = c & 15;
 761         shift = 4;
 762         while (c & 0x80) {
 763                 if (offset >= p->pack_size)
 764                         die("object offset outside of pack file");
 765                 c = *pack++;
 766                 offset++;
 767                 size += (c & 0x7f) << shift;
 768                 shift += 7;
 769         }
 770         *sizep = size;
 771         return offset;
 772 }
 773
 774 void packed_object_info_detail(struct pack_entry *e,
 775                                char *type,
 776                                unsigned long *size,
 777                                unsigned long *store_size,
 778                                int *delta_chain_length,
 779                                unsigned char *base_sha1)
 780 {
 781         struct packed_git *p = e->p;
 782         unsigned long offset, left;
 783         unsigned char *pack;
 784         enum object_type kind;
 785
 786         offset = unpack_object_header(p, e->offset, &kind, size);
 787         pack = p->pack_base + offset;
 788         left = p->pack_size - offset;
 789         if (kind != OBJ_DELTA)
 790                 *delta_chain_length = 0;
 791         else {
 792                 int chain_length = 0;
 793                 memcpy(base_sha1, pack, 20);
 794                 do {
 795                         struct pack_entry base_ent;
 796                         unsigned long junk;
 797
 798                         find_pack_entry_one(pack, &base_ent, p);
 799                         offset = unpack_object_header(p, base_ent.offset,
 800                                                       &kind, &junk);
 801                         pack = p->pack_base + offset;
 802                         chain_length++;
 803                 } while (kind == OBJ_DELTA);
 804                 *delta_chain_length = chain_length;
 805         }
 806         switch (kind) {
 807         case OBJ_COMMIT:
 808                 strcpy(type, "commit");
 809                 break;
 810         case OBJ_TREE:
 811                 strcpy(type, "tree");
 812                 break;
 813         case OBJ_BLOB:
 814                 strcpy(type, "blob");
 815                 break;
 816         case OBJ_TAG:
 817                 strcpy(type, "tag");
 818                 break;
 819         default:
 820                 die("corrupted pack file %s containing object of kind %d",
 821                     p->pack_name, kind);
 822         }
 823         *store_size = 0; /* notyet */
 824 }
 825
 826 static int packed_object_info(struct pack_entry *entry,
 827                               char *type, unsigned long *sizep)
 828 {
 829         struct packed_git *p = entry->p;
 830         unsigned long offset, size, left;
 831         unsigned char *pack;
 832         enum object_type kind;
 833         int retval;
 834
 835         if (use_packed_git(p))
 836                 die("cannot map packed file");
 837
 838         offset = unpack_object_header(p, entry->offset, &kind, &size);
 839         pack = p->pack_base + offset;
 840         left = p->pack_size - offset;
 841
 842         switch (kind) {
 843         case OBJ_DELTA:
 844                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 845                 unuse_packed_git(p);
 846                 return retval;
 847         case OBJ_COMMIT:
 848                 strcpy(type, "commit");
 849                 break;
 850         case OBJ_TREE:
 851                 strcpy(type, "tree");
 852                 break;
 853         case OBJ_BLOB:
 854                 strcpy(type, "blob");
 855                 break;
 856         case OBJ_TAG:
 857                 strcpy(type, "tag");
 858                 break;
 859         default:
 860                 die("corrupted pack file %s containing object of kind %d",
 861                     p->pack_name, kind);
 862         }
 863         if (sizep)
 864                 *sizep = size;
 865         unuse_packed_git(p);
 866         return 0;
 867 }
 868
 869 /* forward declaration for a mutually recursive function */
 870 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 871
 872 static void *unpack_delta_entry(unsigned char *base_sha1,
 873                                 unsigned long delta_size,
 874                                 unsigned long left,
 875                                 char *type,
 876                                 unsigned long *sizep,
 877                                 struct packed_git *p)
 878 {
 879         struct pack_entry base_ent;
 880         void *data, *delta_data, *result, *base;
 881         unsigned long data_size, result_size, base_size;
 882         z_stream stream;
 883         int st;
 884
 885         if (left < 20)
 886                 die("truncated pack file");
 887         data = base_sha1 + 20;
 888         data_size = left - 20;
 889         delta_data = xmalloc(delta_size);
 890
 891         memset(&stream, 0, sizeof(stream));
 892
 893         stream.next_in = data;
 894         stream.avail_in = data_size;
 895         stream.next_out = delta_data;
 896         stream.avail_out = delta_size;
 897
 898         inflateInit(&stream);
 899         st = inflate(&stream, Z_FINISH);
 900         inflateEnd(&stream);
 901         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 902                 die("delta data unpack failed");
 903
 904         /* The base entry _must_ be in the same pack */
 905         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 906                 die("failed to find delta-pack base object %s",
 907                     sha1_to_hex(base_sha1));
 908         base = unpack_entry_gently(&base_ent, type, &base_size);
 909         if (!base)
 910                 die("failed to read delta-pack base object %s",
 911                     sha1_to_hex(base_sha1));
 912         result = patch_delta(base, base_size,
 913                              delta_data, delta_size,
 914                              &result_size);
 915         if (!result)
 916                 die("failed to apply delta");
 917         free(delta_data);
 918         free(base);
 919         *sizep = result_size;
 920         return result;
 921 }
 922
 923 static void *unpack_non_delta_entry(unsigned char *data,
 924                                     unsigned long size,
 925                                     unsigned long left)
 926 {
 927         int st;
 928         z_stream stream;
 929         unsigned char *buffer;
 930
 931         buffer = xmalloc(size + 1);
 932         buffer[size] = 0;
 933         memset(&stream, 0, sizeof(stream));
 934         stream.next_in = data;
 935         stream.avail_in = left;
 936         stream.next_out = buffer;
 937         stream.avail_out = size;
 938
 939         inflateInit(&stream);
 940         st = inflate(&stream, Z_FINISH);
 941         inflateEnd(&stream);
 942         if ((st != Z_STREAM_END) || stream.total_out != size) {
 943                 free(buffer);
 944                 return NULL;
 945         }
 946
 947         return buffer;
 948 }
 949
 950 static void *unpack_entry(struct pack_entry *entry,
 951                           char *type, unsigned long *sizep)
 952 {
 953         struct packed_git *p = entry->p;
 954         void *retval;
 955
 956         if (use_packed_git(p))
 957                 die("cannot map packed file");
 958         retval = unpack_entry_gently(entry, type, sizep);
 959         unuse_packed_git(p);
 960         if (!retval)
 961                 die("corrupted pack file %s", p->pack_name);
 962         return retval;
 963 }
 964
 965 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 966 void *unpack_entry_gently(struct pack_entry *entry,
 967                           char *type, unsigned long *sizep)
 968 {
 969         struct packed_git *p = entry->p;
 970         unsigned long offset, size, left;
 971         unsigned char *pack;
 972         enum object_type kind;
 973         void *retval;
 974
 975         offset = unpack_object_header(p, entry->offset, &kind, &size);
 976         pack = p->pack_base + offset;
 977         left = p->pack_size - offset;
 978         switch (kind) {
 979         case OBJ_DELTA:
 980                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
 981                 return retval;
 982         case OBJ_COMMIT:
 983                 strcpy(type, "commit");
 984                 break;
 985         case OBJ_TREE:
 986                 strcpy(type, "tree");
 987                 break;
 988         case OBJ_BLOB:
 989                 strcpy(type, "blob");
 990                 break;
 991         case OBJ_TAG:
 992                 strcpy(type, "tag");
 993                 break;
 994         default:
 995                 return NULL;
 996         }
 997         *sizep = size;
 998         retval = unpack_non_delta_entry(pack, size, left);
 999         return retval;
1000 }
1001
1002 int num_packed_objects(const struct packed_git *p)
1003 {
1004         /* See check_packed_git_idx() */
1005         return (p->index_size - 20 - 20 - 4*256) / 24;
1006 }
1007
1008 int nth_packed_object_sha1(const struct packed_git *p, int n,
1009                            unsigned char* sha1)
1010 {
1011         void *index = p->index_base + 256;
1012         if (n < 0 || num_packed_objects(p) <= n)
1013                 return -1;
1014         memcpy(sha1, (index + 24 * n + 4), 20);
1015         return 0;
1016 }
1017
1018 int find_pack_entry_one(const unsigned char *sha1,
1019                         struct pack_entry *e, struct packed_git *p)
1020 {
1021         unsigned int *level1_ofs = p->index_base;
1022         int hi = ntohl(level1_ofs[*sha1]);
1023         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1024         void *index = p->index_base + 256;
1025
1026         do {
1027                 int mi = (lo + hi) / 2;
1028                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1029                 if (!cmp) {
1030                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1031                         memcpy(e->sha1, sha1, 20);
1032                         e->p = p;
1033                         return 1;
1034                 }
1035                 if (cmp > 0)
1036                         hi = mi;
1037                 else
1038                         lo = mi+1;
1039         } while (lo < hi);
1040         return 0;
1041 }
1042
1043 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1044 {
1045         struct packed_git *p;
1046         prepare_packed_git();
1047
1048         for (p = packed_git; p; p = p->next) {
1049                 if (find_pack_entry_one(sha1, e, p))
1050                         return 1;
1051         }
1052         return 0;
1053 }
1054
1055 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1056                                   struct packed_git *packs)
1057 {
1058         struct packed_git *p;
1059         struct pack_entry e;
1060
1061         for (p = packs; p; p = p->next) {
1062                 if (find_pack_entry_one(sha1, &e, p))
1063                         return p;
1064         }
1065         return NULL;
1066
1067 }
1068
1069 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1070 {
1071         int status;
1072         unsigned long mapsize, size;
1073         void *map;
1074         z_stream stream;
1075         char hdr[128];
1076
1077         map = map_sha1_file_internal(sha1, &mapsize);
1078         if (!map) {
1079                 struct pack_entry e;
1080
1081                 if (!find_pack_entry(sha1, &e))
1082                         return error("unable to find %s", sha1_to_hex(sha1));
1083                 return packed_object_info(&e, type, sizep);
1084         }
1085         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1086                 status = error("unable to unpack %s header",
1087                                sha1_to_hex(sha1));
1088         if (parse_sha1_header(hdr, type, &size) < 0)
1089                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1090         else {
1091                 status = 0;
1092                 if (sizep)
1093                         *sizep = size;
1094         }
1095         inflateEnd(&stream);
1096         munmap(map, mapsize);
1097         return status;
1098 }
1099
1100 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1101 {
1102         struct pack_entry e;
1103
1104         if (!find_pack_entry(sha1, &e)) {
1105                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1106                 return NULL;
1107         }
1108         return unpack_entry(&e, type, size);
1109 }
1110
1111 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1112 {
1113         unsigned long mapsize;
1114         void *map, *buf;
1115         struct pack_entry e;
1116
1117         if (find_pack_entry(sha1, &e))
1118                 return read_packed_sha1(sha1, type, size);
1119         map = map_sha1_file_internal(sha1, &mapsize);
1120         if (map) {
1121                 buf = unpack_sha1_file(map, mapsize, type, size);
1122                 munmap(map, mapsize);
1123                 return buf;
1124         }
1125         return NULL;
1126 }
1127
1128 void *read_object_with_reference(const unsigned char *sha1,
1129                                  const char *required_type,
1130                                  unsigned long *size,
1131                                  unsigned char *actual_sha1_return)
1132 {
1133         char type[20];
1134         void *buffer;
1135         unsigned long isize;
1136         unsigned char actual_sha1[20];
1137
1138         memcpy(actual_sha1, sha1, 20);
1139         while (1) {
1140                 int ref_length = -1;
1141                 const char *ref_type = NULL;
1142
1143                 buffer = read_sha1_file(actual_sha1, type, &isize);
1144                 if (!buffer)
1145                         return NULL;
1146                 if (!strcmp(type, required_type)) {
1147                         *size = isize;
1148                         if (actual_sha1_return)
1149                                 memcpy(actual_sha1_return, actual_sha1, 20);
1150                         return buffer;
1151                 }
1152                 /* Handle references */
1153                 else if (!strcmp(type, "commit"))
1154                         ref_type = "tree ";
1155                 else if (!strcmp(type, "tag"))
1156                         ref_type = "object ";
1157                 else {
1158                         free(buffer);
1159                         return NULL;
1160                 }
1161                 ref_length = strlen(ref_type);
1162
1163                 if (memcmp(buffer, ref_type, ref_length) ||
1164                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1165                         free(buffer);
1166                         return NULL;
1167                 }
1168                 free(buffer);
1169                 /* Now we have the ID of the referred-to object in
1170                  * actual_sha1.  Check again. */
1171         }
1172 }
1173
1174 char *write_sha1_file_prepare(void *buf,
1175                               unsigned long len,
1176                               const char *type,
1177                               unsigned char *sha1,
1178                               unsigned char *hdr,
1179                               int *hdrlen)
1180 {
1181         SHA_CTX c;
1182
1183         /* Generate the header */
1184         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1185
1186         /* Sha1.. */
1187         SHA1_Init(&c);
1188         SHA1_Update(&c, hdr, *hdrlen);
1189         SHA1_Update(&c, buf, len);
1190         SHA1_Final(sha1, &c);
1191
1192         return sha1_file_name(sha1);
1193 }
1194
1195 /*
1196  * Link the tempfile to the final place, possibly creating the
1197  * last directory level as you do so.
1198  *
1199  * Returns the errno on failure, 0 on success.
1200  */
1201 static int link_temp_to_file(const char *tmpfile, char *filename)
1202 {
1203         int ret;
1204
1205         if (!link(tmpfile, filename))
1206                 return 0;
1207
1208         /*
1209          * Try to mkdir the last path component if that failed
1210          * with an ENOENT.
1211          *
1212          * Re-try the "link()" regardless of whether the mkdir
1213          * succeeds, since a race might mean that somebody
1214          * else succeeded.
1215          */
1216         ret = errno;
1217         if (ret == ENOENT) {
1218                 char *dir = strrchr(filename, '/');
1219                 if (dir) {
1220                         *dir = 0;
1221                         mkdir(filename, 0777);
1222                         *dir = '/';
1223                         if (!link(tmpfile, filename))
1224                                 return 0;
1225                         ret = errno;
1226                 }
1227         }
1228         return ret;
1229 }
1230
1231 /*
1232  * Move the just written object into its final resting place
1233  */
1234 int move_temp_to_file(const char *tmpfile, char *filename)
1235 {
1236         int ret = link_temp_to_file(tmpfile, filename);
1237
1238         /*
1239          * Coda hack - coda doesn't like cross-directory links,
1240          * so we fall back to a rename, which will mean that it
1241          * won't be able to check collisions, but that's not a
1242          * big deal.
1243          *
1244          * The same holds for FAT formatted media.
1245          *
1246          * When this succeeds, we just return 0. We have nothing
1247          * left to unlink.
1248          */
1249         if (ret && ret != EEXIST) {
1250                 if (!rename(tmpfile, filename))
1251                         return 0;
1252                 ret = errno;
1253         }
1254         unlink(tmpfile);
1255         if (ret) {
1256                 if (ret != EEXIST) {
1257                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1258                         return -1;
1259                 }
1260                 /* FIXME!!! Collision check here ? */
1261         }
1262
1263         return 0;
1264 }
1265
1266 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1267 {
1268         int size;
1269         unsigned char *compressed;
1270         z_stream stream;
1271         unsigned char sha1[20];
1272         char *filename;
1273         static char tmpfile[PATH_MAX];
1274         unsigned char hdr[50];
1275         int fd, hdrlen;
1276
1277         /* Normally if we have it in the pack then we do not bother writing
1278          * it out into .git/objects/??/?{38} file.
1279          */
1280         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1281         if (returnsha1)
1282                 memcpy(returnsha1, sha1, 20);
1283         if (has_sha1_file(sha1))
1284                 return 0;
1285         fd = open(filename, O_RDONLY);
1286         if (fd >= 0) {
1287                 /*
1288                  * FIXME!!! We might do collision checking here, but we'd
1289                  * need to uncompress the old file and check it. Later.
1290                  */
1291                 close(fd);
1292                 return 0;
1293         }
1294
1295         if (errno != ENOENT) {
1296                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1297                 return -1;
1298         }
1299
1300         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1301
1302         fd = mkstemp(tmpfile);
1303         if (fd < 0) {
1304                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1305                 return -1;
1306         }
1307
1308         /* Set it up */
1309         memset(&stream, 0, sizeof(stream));
1310         deflateInit(&stream, Z_BEST_COMPRESSION);
1311         size = deflateBound(&stream, len+hdrlen);
1312         compressed = xmalloc(size);
1313
1314         /* Compress it */
1315         stream.next_out = compressed;
1316         stream.avail_out = size;
1317
1318         /* First header.. */
1319         stream.next_in = hdr;
1320         stream.avail_in = hdrlen;
1321         while (deflate(&stream, 0) == Z_OK)
1322                 /* nothing */;
1323
1324         /* Then the data itself.. */
1325         stream.next_in = buf;
1326         stream.avail_in = len;
1327         while (deflate(&stream, Z_FINISH) == Z_OK)
1328                 /* nothing */;
1329         deflateEnd(&stream);
1330         size = stream.total_out;
1331
1332         if (write(fd, compressed, size) != size)
1333                 die("unable to write file");
1334         fchmod(fd, 0444);
1335         close(fd);
1336         free(compressed);
1337
1338         return move_temp_to_file(tmpfile, filename);
1339 }
1340
1341 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1342 {
1343         ssize_t size;
1344         unsigned long objsize;
1345         int posn = 0;
1346         void *map = map_sha1_file_internal(sha1, &objsize);
1347         void *buf = map;
1348         void *temp_obj = NULL;
1349         z_stream stream;
1350
1351         if (!buf) {
1352                 unsigned char *unpacked;
1353                 unsigned long len;
1354                 char type[20];
1355                 char hdr[50];
1356                 int hdrlen;
1357                 // need to unpack and recompress it by itself
1358                 unpacked = read_packed_sha1(sha1, type, &len);
1359
1360                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1361
1362                 /* Set it up */
1363                 memset(&stream, 0, sizeof(stream));
1364                 deflateInit(&stream, Z_BEST_COMPRESSION);
1365                 size = deflateBound(&stream, len + hdrlen);
1366                 temp_obj = buf = xmalloc(size);
1367
1368                 /* Compress it */
1369                 stream.next_out = buf;
1370                 stream.avail_out = size;
1371
1372                 /* First header.. */
1373                 stream.next_in = (void *)hdr;
1374                 stream.avail_in = hdrlen;
1375                 while (deflate(&stream, 0) == Z_OK)
1376                         /* nothing */;
1377
1378                 /* Then the data itself.. */
1379                 stream.next_in = unpacked;
1380                 stream.avail_in = len;
1381                 while (deflate(&stream, Z_FINISH) == Z_OK)
1382                         /* nothing */;
1383                 deflateEnd(&stream);
1384                 free(unpacked);
1385
1386                 objsize = stream.total_out;
1387         }
1388
1389         do {
1390                 size = write(fd, buf + posn, objsize - posn);
1391                 if (size <= 0) {
1392                         if (!size) {
1393                                 fprintf(stderr, "write closed");
1394                         } else {
1395                                 perror("write ");
1396                         }
1397                         return -1;
1398                 }
1399                 posn += size;
1400         } while (posn < objsize);
1401
1402         if (map)
1403                 munmap(map, objsize);
1404         if (temp_obj)
1405                 free(temp_obj);
1406
1407         return 0;
1408 }
1409
1410 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1411                        size_t bufsize, size_t *bufposn)
1412 {
1413         char tmpfile[PATH_MAX];
1414         int local;
1415         z_stream stream;
1416         unsigned char real_sha1[20];
1417         unsigned char discard[4096];
1418         int ret;
1419         SHA_CTX c;
1420
1421         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1422
1423         local = mkstemp(tmpfile);
1424         if (local < 0)
1425                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1426
1427         memset(&stream, 0, sizeof(stream));
1428
1429         inflateInit(&stream);
1430
1431         SHA1_Init(&c);
1432
1433         do {
1434                 ssize_t size;
1435                 if (*bufposn) {
1436                         stream.avail_in = *bufposn;
1437                         stream.next_in = (unsigned char *) buffer;
1438                         do {
1439                                 stream.next_out = discard;
1440                                 stream.avail_out = sizeof(discard);
1441                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1442                                 SHA1_Update(&c, discard, sizeof(discard) -
1443                                             stream.avail_out);
1444                         } while (stream.avail_in && ret == Z_OK);
1445                         write(local, buffer, *bufposn - stream.avail_in);
1446                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1447                                 stream.avail_in);
1448                         *bufposn = stream.avail_in;
1449                         if (ret != Z_OK)
1450                                 break;
1451                 }
1452                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1453                 if (size <= 0) {
1454                         close(local);
1455                         unlink(tmpfile);
1456                         if (!size)
1457                                 return error("Connection closed?");
1458                         perror("Reading from connection");
1459                         return -1;
1460                 }
1461                 *bufposn += size;
1462         } while (1);
1463         inflateEnd(&stream);
1464
1465         close(local);
1466         SHA1_Final(real_sha1, &c);
1467         if (ret != Z_STREAM_END) {
1468                 unlink(tmpfile);
1469                 return error("File %s corrupted", sha1_to_hex(sha1));
1470         }
1471         if (memcmp(sha1, real_sha1, 20)) {
1472                 unlink(tmpfile);
1473                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1474         }
1475
1476         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1477 }
1478
1479 int has_pack_index(const unsigned char *sha1)
1480 {
1481         struct stat st;
1482         if (stat(sha1_pack_index_name(sha1), &st))
1483                 return 0;
1484         return 1;
1485 }
1486
1487 int has_pack_file(const unsigned char *sha1)
1488 {
1489         struct stat st;
1490         if (stat(sha1_pack_name(sha1), &st))
1491                 return 0;
1492         return 1;
1493 }
1494
1495 int has_sha1_pack(const unsigned char *sha1)
1496 {
1497         struct pack_entry e;
1498         return find_pack_entry(sha1, &e);
1499 }
1500
1501 int has_sha1_file(const unsigned char *sha1)
1502 {
1503         struct stat st;
1504         struct pack_entry e;
1505
1506         if (find_pack_entry(sha1, &e))
1507                 return 1;
1508         return find_sha1_file(sha1, &st) ? 1 : 0;
1509 }
1510
1511 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1512 {
1513         unsigned long size = st->st_size;
1514         void *buf;
1515         int ret;
1516         unsigned char hdr[50];
1517         int hdrlen;
1518
1519         buf = "";
1520         if (size)
1521                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1522         close(fd);
1523         if (buf == MAP_FAILED)
1524                 return -1;
1525
1526         if (!type)
1527                 type = "blob";
1528         if (write_object)
1529                 ret = write_sha1_file(buf, size, type, sha1);
1530         else {
1531                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1532                 ret = 0;
1533         }
1534         if (size)
1535                 munmap(buf, size);
1536         return ret;
1537 }
1538
1539 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1540 {
1541         int fd;
1542         char *target;
1543
1544         switch (st->st_mode & S_IFMT) {
1545         case S_IFREG:
1546                 fd = open(path, O_RDONLY);
1547                 if (fd < 0)
1548                         return error("open(\"%s\"): %s", path,
1549                                      strerror(errno));
1550                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1551                         return error("%s: failed to insert into database",
1552                                      path);
1553                 break;
1554         case S_IFLNK:
1555                 target = xmalloc(st->st_size+1);
1556                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1557                         char *errstr = strerror(errno);
1558                         free(target);
1559                         return error("readlink(\"%s\"): %s", path,
1560                                      errstr);
1561                 }
1562                 if (!write_object) {
1563                         unsigned char hdr[50];
1564                         int hdrlen;
1565                         write_sha1_file_prepare(target, st->st_size, "blob",
1566                                                 sha1, hdr, &hdrlen);
1567                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1568                         return error("%s: failed to insert into database",
1569                                      path);
1570                 free(target);
1571                 break;
1572         default:
1573                 return error("%s: unsupported file type", path);
1574         }
1575         return 0;
1576 }