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