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)
 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         return p;
 448 }
 449
 450 struct packed_git *parse_pack_index(unsigned char *sha1)
 451 {
 452         char *path = sha1_pack_index_name(sha1);
 453         return parse_pack_index_file(sha1, path);
 454 }
 455
 456 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 457 {
 458         struct packed_git *p;
 459         unsigned long idx_size;
 460         void *idx_map;
 461         char *path;
 462
 463         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 464                 return NULL;
 465
 466         path = sha1_pack_name(sha1);
 467
 468         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 469         strcpy(p->pack_name, path);
 470         p->index_size = idx_size;
 471         p->pack_size = 0;
 472         p->index_base = idx_map;
 473         p->next = NULL;
 474         p->pack_base = NULL;
 475         p->pack_last_used = 0;
 476         p->pack_use_cnt = 0;
 477         memcpy(p->sha1, sha1, 20);
 478         return p;
 479 }
 480
 481 void install_packed_git(struct packed_git *pack)
 482 {
 483         pack->next = packed_git;
 484         packed_git = pack;
 485 }
 486
 487 static void prepare_packed_git_one(char *objdir)
 488 {
 489         char path[PATH_MAX];
 490         int len;
 491         DIR *dir;
 492         struct dirent *de;
 493
 494         sprintf(path, "%s/pack", objdir);
 495         len = strlen(path);
 496         dir = opendir(path);
 497         if (!dir)
 498                 return;
 499         path[len++] = '/';
 500         while ((de = readdir(dir)) != NULL) {
 501                 int namelen = strlen(de->d_name);
 502                 struct packed_git *p;
 503
 504                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 505                         continue;
 506
 507                 /* we have .idx.  Is it a file we can map? */
 508                 strcpy(path + len, de->d_name);
 509                 p = add_packed_git(path, len + namelen);
 510                 if (!p)
 511                         continue;
 512                 p->next = packed_git;
 513                 packed_git = p;
 514         }
 515         closedir(dir);
 516 }
 517
 518 void prepare_packed_git(void)
 519 {
 520         static int run_once = 0;
 521         struct alternate_object_database *alt;
 522
 523         if (run_once)
 524                 return;
 525         prepare_packed_git_one(get_object_directory());
 526         prepare_alt_odb();
 527         for (alt = alt_odb_list; alt; alt = alt->next) {
 528                 alt->name[0] = 0;
 529                 prepare_packed_git_one(alt->base);
 530         }
 531         run_once = 1;
 532 }
 533
 534 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 535 {
 536         char header[100];
 537         unsigned char real_sha1[20];
 538         SHA_CTX c;
 539
 540         SHA1_Init(&c);
 541         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 542         SHA1_Update(&c, map, size);
 543         SHA1_Final(real_sha1, &c);
 544         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 545 }
 546
 547 static void *map_sha1_file_internal(const unsigned char *sha1,
 548                                     unsigned long *size)
 549 {
 550         struct stat st;
 551         void *map;
 552         int fd;
 553         char *filename = find_sha1_file(sha1, &st);
 554
 555         if (!filename) {
 556                 return NULL;
 557         }
 558
 559         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 560         if (fd < 0) {
 561                 /* See if it works without O_NOATIME */
 562                 switch (sha1_file_open_flag) {
 563                 default:
 564                         fd = open(filename, O_RDONLY);
 565                         if (fd >= 0)
 566                                 break;
 567                 /* Fallthrough */
 568                 case 0:
 569                         return NULL;
 570                 }
 571
 572                 /* If it failed once, it will probably fail again.
 573                  * Stop using O_NOATIME
 574                  */
 575                 sha1_file_open_flag = 0;
 576         }
 577         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 578         close(fd);
 579         if (map == MAP_FAILED)
 580                 return NULL;
 581         *size = st.st_size;
 582         return map;
 583 }
 584
 585 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 586 {
 587         /* Get the data stream */
 588         memset(stream, 0, sizeof(*stream));
 589         stream->next_in = map;
 590         stream->avail_in = mapsize;
 591         stream->next_out = buffer;
 592         stream->avail_out = size;
 593
 594         inflateInit(stream);
 595         return inflate(stream, 0);
 596 }
 597
 598 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 599 {
 600         int bytes = strlen(buffer) + 1;
 601         unsigned char *buf = xmalloc(1+size);
 602
 603         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 604         bytes = stream->total_out - bytes;
 605         if (bytes < size) {
 606                 stream->next_out = buf + bytes;
 607                 stream->avail_out = size - bytes;
 608                 while (inflate(stream, Z_FINISH) == Z_OK)
 609                         /* nothing */;
 610         }
 611         buf[size] = 0;
 612         inflateEnd(stream);
 613         return buf;
 614 }
 615
 616 /*
 617  * We used to just use "sscanf()", but that's actually way
 618  * too permissive for what we want to check. So do an anal
 619  * object header parse by hand.
 620  */
 621 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 622 {
 623         int i;
 624         unsigned long size;
 625
 626         /*
 627          * The type can be at most ten bytes (including the
 628          * terminating '\0' that we add), and is followed by
 629          * a space.
 630          */
 631         i = 10;
 632         for (;;) {
 633                 char c = *hdr++;
 634                 if (c == ' ')
 635                         break;
 636                 if (!--i)
 637                         return -1;
 638                 *type++ = c;
 639         }
 640         *type = 0;
 641
 642         /*
 643          * The length must follow immediately, and be in canonical
 644          * decimal format (ie "010" is not valid).
 645          */
 646         size = *hdr++ - '0';
 647         if (size > 9)
 648                 return -1;
 649         if (size) {
 650                 for (;;) {
 651                         unsigned long c = *hdr - '0';
 652                         if (c > 9)
 653                                 break;
 654                         hdr++;
 655                         size = size * 10 + c;
 656                 }
 657         }
 658         *sizep = size;
 659
 660         /*
 661          * The length must be followed by a zero byte
 662          */
 663         return *hdr ? -1 : 0;
 664 }
 665
 666 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 667 {
 668         int ret;
 669         z_stream stream;
 670         char hdr[8192];
 671
 672         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 673         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 674                 return NULL;
 675
 676         return unpack_sha1_rest(&stream, hdr, *size);
 677 }
 678
 679 /* forward declaration for a mutually recursive function */
 680 static int packed_object_info(struct pack_entry *entry,
 681                               char *type, unsigned long *sizep);
 682
 683 static int packed_delta_info(unsigned char *base_sha1,
 684                              unsigned long delta_size,
 685                              unsigned long left,
 686                              char *type,
 687                              unsigned long *sizep,
 688                              struct packed_git *p)
 689 {
 690         struct pack_entry base_ent;
 691
 692         if (left < 20)
 693                 die("truncated pack file");
 694
 695         /* The base entry _must_ be in the same pack */
 696         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 697                 die("failed to find delta-pack base object %s",
 698                     sha1_to_hex(base_sha1));
 699
 700         /* We choose to only get the type of the base object and
 701          * ignore potentially corrupt pack file that expects the delta
 702          * based on a base with a wrong size.  This saves tons of
 703          * inflate() calls.
 704          */
 705
 706         if (packed_object_info(&base_ent, type, NULL))
 707                 die("cannot get info for delta-pack base");
 708
 709         if (sizep) {
 710                 const unsigned char *data;
 711                 unsigned char delta_head[64];
 712                 unsigned long result_size;
 713                 z_stream stream;
 714                 int st;
 715
 716                 memset(&stream, 0, sizeof(stream));
 717
 718                 data = stream.next_in = base_sha1 + 20;
 719                 stream.avail_in = left - 20;
 720                 stream.next_out = delta_head;
 721                 stream.avail_out = sizeof(delta_head);
 722
 723                 inflateInit(&stream);
 724                 st = inflate(&stream, Z_FINISH);
 725                 inflateEnd(&stream);
 726                 if ((st != Z_STREAM_END) &&
 727                     stream.total_out != sizeof(delta_head))
 728                         die("delta data unpack-initial failed");
 729
 730                 /* Examine the initial part of the delta to figure out
 731                  * the result size.
 732                  */
 733                 data = delta_head;
 734                 get_delta_hdr_size(&data); /* ignore base size */
 735
 736                 /* Read the result size */
 737                 result_size = get_delta_hdr_size(&data);
 738                 *sizep = result_size;
 739         }
 740         return 0;
 741 }
 742
 743 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 744         enum object_type *type, unsigned long *sizep)
 745 {
 746         unsigned shift;
 747         unsigned char *pack, c;
 748         unsigned long size;
 749
 750         if (offset >= p->pack_size)
 751                 die("object offset outside of pack file");
 752
 753         pack =  p->pack_base + offset;
 754         c = *pack++;
 755         offset++;
 756         *type = (c >> 4) & 7;
 757         size = c & 15;
 758         shift = 4;
 759         while (c & 0x80) {
 760                 if (offset >= p->pack_size)
 761                         die("object offset outside of pack file");
 762                 c = *pack++;
 763                 offset++;
 764                 size += (c & 0x7f) << shift;
 765                 shift += 7;
 766         }
 767         *sizep = size;
 768         return offset;
 769 }
 770
 771 void packed_object_info_detail(struct pack_entry *e,
 772                                char *type,
 773                                unsigned long *size,
 774                                unsigned long *store_size,
 775                                int *delta_chain_length,
 776                                unsigned char *base_sha1)
 777 {
 778         struct packed_git *p = e->p;
 779         unsigned long offset, left;
 780         unsigned char *pack;
 781         enum object_type kind;
 782
 783         offset = unpack_object_header(p, e->offset, &kind, size);
 784         pack = p->pack_base + offset;
 785         left = p->pack_size - offset;
 786         if (kind != OBJ_DELTA)
 787                 *delta_chain_length = 0;
 788         else {
 789                 int chain_length = 0;
 790                 memcpy(base_sha1, pack, 20);
 791                 do {
 792                         struct pack_entry base_ent;
 793                         unsigned long junk;
 794
 795                         find_pack_entry_one(pack, &base_ent, p);
 796                         offset = unpack_object_header(p, base_ent.offset,
 797                                                       &kind, &junk);
 798                         pack = p->pack_base + offset;
 799                         chain_length++;
 800                 } while (kind == OBJ_DELTA);
 801                 *delta_chain_length = chain_length;
 802         }
 803         switch (kind) {
 804         case OBJ_COMMIT:
 805                 strcpy(type, "commit");
 806                 break;
 807         case OBJ_TREE:
 808                 strcpy(type, "tree");
 809                 break;
 810         case OBJ_BLOB:
 811                 strcpy(type, "blob");
 812                 break;
 813         case OBJ_TAG:
 814                 strcpy(type, "tag");
 815                 break;
 816         default:
 817                 die("corrupted pack file %s containing object of kind %d",
 818                     p->pack_name, kind);
 819         }
 820         *store_size = 0; /* notyet */
 821 }
 822
 823 static int packed_object_info(struct pack_entry *entry,
 824                               char *type, unsigned long *sizep)
 825 {
 826         struct packed_git *p = entry->p;
 827         unsigned long offset, size, left;
 828         unsigned char *pack;
 829         enum object_type kind;
 830         int retval;
 831
 832         if (use_packed_git(p))
 833                 die("cannot map packed file");
 834
 835         offset = unpack_object_header(p, entry->offset, &kind, &size);
 836         pack = p->pack_base + offset;
 837         left = p->pack_size - offset;
 838
 839         switch (kind) {
 840         case OBJ_DELTA:
 841                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 842                 unuse_packed_git(p);
 843                 return retval;
 844         case OBJ_COMMIT:
 845                 strcpy(type, "commit");
 846                 break;
 847         case OBJ_TREE:
 848                 strcpy(type, "tree");
 849                 break;
 850         case OBJ_BLOB:
 851                 strcpy(type, "blob");
 852                 break;
 853         case OBJ_TAG:
 854                 strcpy(type, "tag");
 855                 break;
 856         default:
 857                 die("corrupted pack file %s containing object of kind %d",
 858                     p->pack_name, kind);
 859         }
 860         if (sizep)
 861                 *sizep = size;
 862         unuse_packed_git(p);
 863         return 0;
 864 }
 865
 866 /* forward declaration for a mutually recursive function */
 867 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 868
 869 static void *unpack_delta_entry(unsigned char *base_sha1,
 870                                 unsigned long delta_size,
 871                                 unsigned long left,
 872                                 char *type,
 873                                 unsigned long *sizep,
 874                                 struct packed_git *p)
 875 {
 876         struct pack_entry base_ent;
 877         void *data, *delta_data, *result, *base;
 878         unsigned long data_size, result_size, base_size;
 879         z_stream stream;
 880         int st;
 881
 882         if (left < 20)
 883                 die("truncated pack file");
 884         data = base_sha1 + 20;
 885         data_size = left - 20;
 886         delta_data = xmalloc(delta_size);
 887
 888         memset(&stream, 0, sizeof(stream));
 889
 890         stream.next_in = data;
 891         stream.avail_in = data_size;
 892         stream.next_out = delta_data;
 893         stream.avail_out = delta_size;
 894
 895         inflateInit(&stream);
 896         st = inflate(&stream, Z_FINISH);
 897         inflateEnd(&stream);
 898         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 899                 die("delta data unpack failed");
 900
 901         /* The base entry _must_ be in the same pack */
 902         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 903                 die("failed to find delta-pack base object %s",
 904                     sha1_to_hex(base_sha1));
 905         base = unpack_entry_gently(&base_ent, type, &base_size);
 906         if (!base)
 907                 die("failed to read delta-pack base object %s",
 908                     sha1_to_hex(base_sha1));
 909         result = patch_delta(base, base_size,
 910                              delta_data, delta_size,
 911                              &result_size);
 912         if (!result)
 913                 die("failed to apply delta");
 914         free(delta_data);
 915         free(base);
 916         *sizep = result_size;
 917         return result;
 918 }
 919
 920 static void *unpack_non_delta_entry(unsigned char *data,
 921                                     unsigned long size,
 922                                     unsigned long left)
 923 {
 924         int st;
 925         z_stream stream;
 926         unsigned char *buffer;
 927
 928         buffer = xmalloc(size + 1);
 929         buffer[size] = 0;
 930         memset(&stream, 0, sizeof(stream));
 931         stream.next_in = data;
 932         stream.avail_in = left;
 933         stream.next_out = buffer;
 934         stream.avail_out = size;
 935
 936         inflateInit(&stream);
 937         st = inflate(&stream, Z_FINISH);
 938         inflateEnd(&stream);
 939         if ((st != Z_STREAM_END) || stream.total_out != size) {
 940                 free(buffer);
 941                 return NULL;
 942         }
 943
 944         return buffer;
 945 }
 946
 947 static void *unpack_entry(struct pack_entry *entry,
 948                           char *type, unsigned long *sizep)
 949 {
 950         struct packed_git *p = entry->p;
 951         void *retval;
 952
 953         if (use_packed_git(p))
 954                 die("cannot map packed file");
 955         retval = unpack_entry_gently(entry, type, sizep);
 956         unuse_packed_git(p);
 957         if (!retval)
 958                 die("corrupted pack file %s", p->pack_name);
 959         return retval;
 960 }
 961
 962 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 963 void *unpack_entry_gently(struct pack_entry *entry,
 964                           char *type, unsigned long *sizep)
 965 {
 966         struct packed_git *p = entry->p;
 967         unsigned long offset, size, left;
 968         unsigned char *pack;
 969         enum object_type kind;
 970         void *retval;
 971
 972         offset = unpack_object_header(p, entry->offset, &kind, &size);
 973         pack = p->pack_base + offset;
 974         left = p->pack_size - offset;
 975         switch (kind) {
 976         case OBJ_DELTA:
 977                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
 978                 return retval;
 979         case OBJ_COMMIT:
 980                 strcpy(type, "commit");
 981                 break;
 982         case OBJ_TREE:
 983                 strcpy(type, "tree");
 984                 break;
 985         case OBJ_BLOB:
 986                 strcpy(type, "blob");
 987                 break;
 988         case OBJ_TAG:
 989                 strcpy(type, "tag");
 990                 break;
 991         default:
 992                 return NULL;
 993         }
 994         *sizep = size;
 995         retval = unpack_non_delta_entry(pack, size, left);
 996         return retval;
 997 }
 998
 999 int num_packed_objects(const struct packed_git *p)
1000 {
1001         /* See check_packed_git_idx() */
1002         return (p->index_size - 20 - 20 - 4*256) / 24;
1003 }
1004
1005 int nth_packed_object_sha1(const struct packed_git *p, int n,
1006                            unsigned char* sha1)
1007 {
1008         void *index = p->index_base + 256;
1009         if (n < 0 || num_packed_objects(p) <= n)
1010                 return -1;
1011         memcpy(sha1, (index + 24 * n + 4), 20);
1012         return 0;
1013 }
1014
1015 int find_pack_entry_one(const unsigned char *sha1,
1016                         struct pack_entry *e, struct packed_git *p)
1017 {
1018         unsigned int *level1_ofs = p->index_base;
1019         int hi = ntohl(level1_ofs[*sha1]);
1020         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1021         void *index = p->index_base + 256;
1022
1023         do {
1024                 int mi = (lo + hi) / 2;
1025                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1026                 if (!cmp) {
1027                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1028                         memcpy(e->sha1, sha1, 20);
1029                         e->p = p;
1030                         return 1;
1031                 }
1032                 if (cmp > 0)
1033                         hi = mi;
1034                 else
1035                         lo = mi+1;
1036         } while (lo < hi);
1037         return 0;
1038 }
1039
1040 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1041 {
1042         struct packed_git *p;
1043         prepare_packed_git();
1044
1045         for (p = packed_git; p; p = p->next) {
1046                 if (find_pack_entry_one(sha1, e, p))
1047                         return 1;
1048         }
1049         return 0;
1050 }
1051
1052 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1053                                   struct packed_git *packs)
1054 {
1055         struct packed_git *p;
1056         struct pack_entry e;
1057
1058         for (p = packs; p; p = p->next) {
1059                 if (find_pack_entry_one(sha1, &e, p))
1060                         return p;
1061         }
1062         return NULL;
1063
1064 }
1065
1066 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1067 {
1068         int status;
1069         unsigned long mapsize, size;
1070         void *map;
1071         z_stream stream;
1072         char hdr[128];
1073
1074         map = map_sha1_file_internal(sha1, &mapsize);
1075         if (!map) {
1076                 struct pack_entry e;
1077
1078                 if (!find_pack_entry(sha1, &e))
1079                         return error("unable to find %s", sha1_to_hex(sha1));
1080                 return packed_object_info(&e, type, sizep);
1081         }
1082         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1083                 status = error("unable to unpack %s header",
1084                                sha1_to_hex(sha1));
1085         if (parse_sha1_header(hdr, type, &size) < 0)
1086                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1087         else {
1088                 status = 0;
1089                 if (sizep)
1090                         *sizep = size;
1091         }
1092         inflateEnd(&stream);
1093         munmap(map, mapsize);
1094         return status;
1095 }
1096
1097 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1098 {
1099         struct pack_entry e;
1100
1101         if (!find_pack_entry(sha1, &e)) {
1102                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1103                 return NULL;
1104         }
1105         return unpack_entry(&e, type, size);
1106 }
1107
1108 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1109 {
1110         unsigned long mapsize;
1111         void *map, *buf;
1112         struct pack_entry e;
1113
1114         if (find_pack_entry(sha1, &e))
1115                 return read_packed_sha1(sha1, type, size);
1116         map = map_sha1_file_internal(sha1, &mapsize);
1117         if (map) {
1118                 buf = unpack_sha1_file(map, mapsize, type, size);
1119                 munmap(map, mapsize);
1120                 return buf;
1121         }
1122         return NULL;
1123 }
1124
1125 void *read_object_with_reference(const unsigned char *sha1,
1126                                  const char *required_type,
1127                                  unsigned long *size,
1128                                  unsigned char *actual_sha1_return)
1129 {
1130         char type[20];
1131         void *buffer;
1132         unsigned long isize;
1133         unsigned char actual_sha1[20];
1134
1135         memcpy(actual_sha1, sha1, 20);
1136         while (1) {
1137                 int ref_length = -1;
1138                 const char *ref_type = NULL;
1139
1140                 buffer = read_sha1_file(actual_sha1, type, &isize);
1141                 if (!buffer)
1142                         return NULL;
1143                 if (!strcmp(type, required_type)) {
1144                         *size = isize;
1145                         if (actual_sha1_return)
1146                                 memcpy(actual_sha1_return, actual_sha1, 20);
1147                         return buffer;
1148                 }
1149                 /* Handle references */
1150                 else if (!strcmp(type, "commit"))
1151                         ref_type = "tree ";
1152                 else if (!strcmp(type, "tag"))
1153                         ref_type = "object ";
1154                 else {
1155                         free(buffer);
1156                         return NULL;
1157                 }
1158                 ref_length = strlen(ref_type);
1159
1160                 if (memcmp(buffer, ref_type, ref_length) ||
1161                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1162                         free(buffer);
1163                         return NULL;
1164                 }
1165                 free(buffer);
1166                 /* Now we have the ID of the referred-to object in
1167                  * actual_sha1.  Check again. */
1168         }
1169 }
1170
1171 char *write_sha1_file_prepare(void *buf,
1172                               unsigned long len,
1173                               const char *type,
1174                               unsigned char *sha1,
1175                               unsigned char *hdr,
1176                               int *hdrlen)
1177 {
1178         SHA_CTX c;
1179
1180         /* Generate the header */
1181         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1182
1183         /* Sha1.. */
1184         SHA1_Init(&c);
1185         SHA1_Update(&c, hdr, *hdrlen);
1186         SHA1_Update(&c, buf, len);
1187         SHA1_Final(sha1, &c);
1188
1189         return sha1_file_name(sha1);
1190 }
1191
1192 /*
1193  * Link the tempfile to the final place, possibly creating the
1194  * last directory level as you do so.
1195  *
1196  * Returns the errno on failure, 0 on success.
1197  */
1198 static int link_temp_to_file(const char *tmpfile, char *filename)
1199 {
1200         int ret;
1201
1202         if (!link(tmpfile, filename))
1203                 return 0;
1204
1205         /*
1206          * Try to mkdir the last path component if that failed
1207          * with an ENOENT.
1208          *
1209          * Re-try the "link()" regardless of whether the mkdir
1210          * succeeds, since a race might mean that somebody
1211          * else succeeded.
1212          */
1213         ret = errno;
1214         if (ret == ENOENT) {
1215                 char *dir = strrchr(filename, '/');
1216                 if (dir) {
1217                         *dir = 0;
1218                         mkdir(filename, 0777);
1219                         *dir = '/';
1220                         if (!link(tmpfile, filename))
1221                                 return 0;
1222                         ret = errno;
1223                 }
1224         }
1225         return ret;
1226 }
1227
1228 /*
1229  * Move the just written object into its final resting place
1230  */
1231 int move_temp_to_file(const char *tmpfile, char *filename)
1232 {
1233         int ret = link_temp_to_file(tmpfile, filename);
1234         if (ret) {
1235                 /*
1236                  * Coda hack - coda doesn't like cross-directory links,
1237                  * so we fall back to a rename, which will mean that it
1238                  * won't be able to check collisions, but that's not a
1239                  * big deal.
1240                  *
1241                  * When this succeeds, we just return 0. We have nothing
1242                  * left to unlink.
1243                  */
1244                 if (ret == EXDEV && !rename(tmpfile, filename))
1245                         return 0;
1246         }
1247         unlink(tmpfile);
1248         if (ret) {
1249                 if (ret != EEXIST) {
1250                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1251                         return -1;
1252                 }
1253                 /* FIXME!!! Collision check here ? */
1254         }
1255
1256         return 0;
1257 }
1258
1259 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1260 {
1261         int size;
1262         unsigned char *compressed;
1263         z_stream stream;
1264         unsigned char sha1[20];
1265         char *filename;
1266         static char tmpfile[PATH_MAX];
1267         unsigned char hdr[50];
1268         int fd, hdrlen;
1269
1270         /* Normally if we have it in the pack then we do not bother writing
1271          * it out into .git/objects/??/?{38} file.
1272          */
1273         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1274         if (returnsha1)
1275                 memcpy(returnsha1, sha1, 20);
1276         if (has_sha1_file(sha1))
1277                 return 0;
1278         fd = open(filename, O_RDONLY);
1279         if (fd >= 0) {
1280                 /*
1281                  * FIXME!!! We might do collision checking here, but we'd
1282                  * need to uncompress the old file and check it. Later.
1283                  */
1284                 close(fd);
1285                 return 0;
1286         }
1287
1288         if (errno != ENOENT) {
1289                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1290                 return -1;
1291         }
1292
1293         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1294
1295         fd = mkstemp(tmpfile);
1296         if (fd < 0) {
1297                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1298                 return -1;
1299         }
1300
1301         /* Set it up */
1302         memset(&stream, 0, sizeof(stream));
1303         deflateInit(&stream, Z_BEST_COMPRESSION);
1304         size = deflateBound(&stream, len+hdrlen);
1305         compressed = xmalloc(size);
1306
1307         /* Compress it */
1308         stream.next_out = compressed;
1309         stream.avail_out = size;
1310
1311         /* First header.. */
1312         stream.next_in = hdr;
1313         stream.avail_in = hdrlen;
1314         while (deflate(&stream, 0) == Z_OK)
1315                 /* nothing */;
1316
1317         /* Then the data itself.. */
1318         stream.next_in = buf;
1319         stream.avail_in = len;
1320         while (deflate(&stream, Z_FINISH) == Z_OK)
1321                 /* nothing */;
1322         deflateEnd(&stream);
1323         size = stream.total_out;
1324
1325         if (write(fd, compressed, size) != size)
1326                 die("unable to write file");
1327         fchmod(fd, 0444);
1328         close(fd);
1329         free(compressed);
1330
1331         return move_temp_to_file(tmpfile, filename);
1332 }
1333
1334 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1335 {
1336         ssize_t size;
1337         unsigned long objsize;
1338         int posn = 0;
1339         void *map = map_sha1_file_internal(sha1, &objsize);
1340         void *buf = map;
1341         void *temp_obj = NULL;
1342         z_stream stream;
1343
1344         if (!buf) {
1345                 unsigned char *unpacked;
1346                 unsigned long len;
1347                 char type[20];
1348                 char hdr[50];
1349                 int hdrlen;
1350                 // need to unpack and recompress it by itself
1351                 unpacked = read_packed_sha1(sha1, type, &len);
1352
1353                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1354
1355                 /* Set it up */
1356                 memset(&stream, 0, sizeof(stream));
1357                 deflateInit(&stream, Z_BEST_COMPRESSION);
1358                 size = deflateBound(&stream, len + hdrlen);
1359                 temp_obj = buf = xmalloc(size);
1360
1361                 /* Compress it */
1362                 stream.next_out = buf;
1363                 stream.avail_out = size;
1364
1365                 /* First header.. */
1366                 stream.next_in = (void *)hdr;
1367                 stream.avail_in = hdrlen;
1368                 while (deflate(&stream, 0) == Z_OK)
1369                         /* nothing */;
1370
1371                 /* Then the data itself.. */
1372                 stream.next_in = unpacked;
1373                 stream.avail_in = len;
1374                 while (deflate(&stream, Z_FINISH) == Z_OK)
1375                         /* nothing */;
1376                 deflateEnd(&stream);
1377                 free(unpacked);
1378
1379                 objsize = stream.total_out;
1380         }
1381
1382         do {
1383                 size = write(fd, buf + posn, objsize - posn);
1384                 if (size <= 0) {
1385                         if (!size) {
1386                                 fprintf(stderr, "write closed");
1387                         } else {
1388                                 perror("write ");
1389                         }
1390                         return -1;
1391                 }
1392                 posn += size;
1393         } while (posn < objsize);
1394
1395         if (map)
1396                 munmap(map, objsize);
1397         if (temp_obj)
1398                 free(temp_obj);
1399
1400         return 0;
1401 }
1402
1403 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1404                        size_t bufsize, size_t *bufposn)
1405 {
1406         char tmpfile[PATH_MAX];
1407         int local;
1408         z_stream stream;
1409         unsigned char real_sha1[20];
1410         unsigned char discard[4096];
1411         int ret;
1412         SHA_CTX c;
1413
1414         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1415
1416         local = mkstemp(tmpfile);
1417         if (local < 0)
1418                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1419
1420         memset(&stream, 0, sizeof(stream));
1421
1422         inflateInit(&stream);
1423
1424         SHA1_Init(&c);
1425
1426         do {
1427                 ssize_t size;
1428                 if (*bufposn) {
1429                         stream.avail_in = *bufposn;
1430                         stream.next_in = (unsigned char *) buffer;
1431                         do {
1432                                 stream.next_out = discard;
1433                                 stream.avail_out = sizeof(discard);
1434                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1435                                 SHA1_Update(&c, discard, sizeof(discard) -
1436                                             stream.avail_out);
1437                         } while (stream.avail_in && ret == Z_OK);
1438                         write(local, buffer, *bufposn - stream.avail_in);
1439                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1440                                 stream.avail_in);
1441                         *bufposn = stream.avail_in;
1442                         if (ret != Z_OK)
1443                                 break;
1444                 }
1445                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1446                 if (size <= 0) {
1447                         close(local);
1448                         unlink(tmpfile);
1449                         if (!size)
1450                                 return error("Connection closed?");
1451                         perror("Reading from connection");
1452                         return -1;
1453                 }
1454                 *bufposn += size;
1455         } while (1);
1456         inflateEnd(&stream);
1457
1458         close(local);
1459         SHA1_Final(real_sha1, &c);
1460         if (ret != Z_STREAM_END) {
1461                 unlink(tmpfile);
1462                 return error("File %s corrupted", sha1_to_hex(sha1));
1463         }
1464         if (memcmp(sha1, real_sha1, 20)) {
1465                 unlink(tmpfile);
1466                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1467         }
1468
1469         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1470 }
1471
1472 int has_pack_index(const unsigned char *sha1)
1473 {
1474         struct stat st;
1475         if (stat(sha1_pack_index_name(sha1), &st))
1476                 return 0;
1477         return 1;
1478 }
1479
1480 int has_pack_file(const unsigned char *sha1)
1481 {
1482         struct stat st;
1483         if (stat(sha1_pack_name(sha1), &st))
1484                 return 0;
1485         return 1;
1486 }
1487
1488 int has_sha1_pack(const unsigned char *sha1)
1489 {
1490         struct pack_entry e;
1491         return find_pack_entry(sha1, &e);
1492 }
1493
1494 int has_sha1_file(const unsigned char *sha1)
1495 {
1496         struct stat st;
1497         struct pack_entry e;
1498
1499         if (find_pack_entry(sha1, &e))
1500                 return 1;
1501         return find_sha1_file(sha1, &st) ? 1 : 0;
1502 }
1503
1504 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1505 {
1506         unsigned long size = st->st_size;
1507         void *buf;
1508         int ret;
1509         unsigned char hdr[50];
1510         int hdrlen;
1511
1512         buf = "";
1513         if (size)
1514                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1515         close(fd);
1516         if (buf == MAP_FAILED)
1517                 return -1;
1518
1519         if (!type)
1520                 type = "blob";
1521         if (write_object)
1522                 ret = write_sha1_file(buf, size, type, sha1);
1523         else {
1524                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1525                 ret = 0;
1526         }
1527         if (size)
1528                 munmap(buf, size);
1529         return ret;
1530 }
1531
1532 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1533 {
1534         int fd;
1535         char *target;
1536
1537         switch (st->st_mode & S_IFMT) {
1538         case S_IFREG:
1539                 fd = open(path, O_RDONLY);
1540                 if (fd < 0)
1541                         return error("open(\"%s\"): %s", path,
1542                                      strerror(errno));
1543                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1544                         return error("%s: failed to insert into database",
1545                                      path);
1546                 break;
1547         case S_IFLNK:
1548                 target = xmalloc(st->st_size+1);
1549                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1550                         char *errstr = strerror(errno);
1551                         free(target);
1552                         return error("readlink(\"%s\"): %s", path,
1553                                      errstr);
1554                 }
1555                 if (!write_object) {
1556                         unsigned char hdr[50];
1557                         int hdrlen;
1558                         write_sha1_file_prepare(target, st->st_size, "blob",
1559                                                 sha1, hdr, &hdrlen);
1560                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1561                         return error("%s: failed to insert into database",
1562                                      path);
1563                 free(target);
1564                 break;
1565         default:
1566                 return error("%s: unsupported file type", path);
1567         }
1568         return 0;
1569 }