git.oblomov.eu Git - git/blob - sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include <sys/types.h>
  10 #include <dirent.h>
  11 #include "cache.h"
  12 #include "delta.h"
  13 #include "pack.h"
  14
  15 #ifndef O_NOATIME
  16 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  17 #define O_NOATIME 01000000
  18 #else
  19 #define O_NOATIME 0
  20 #endif
  21 #endif
  22
  23 const unsigned char null_sha1[20] = { 0, };
  24
  25 static unsigned int sha1_file_open_flag = O_NOATIME;
  26
  27 static unsigned hexval(char c)
  28 {
  29         if (c >= '0' && c <= '9')
  30                 return c - '0';
  31         if (c >= 'a' && c <= 'f')
  32                 return c - 'a' + 10;
  33         if (c >= 'A' && c <= 'F')
  34                 return c - 'A' + 10;
  35         return ~0;
  36 }
  37
  38 int get_sha1_hex(const char *hex, unsigned char *sha1)
  39 {
  40         int i;
  41         for (i = 0; i < 20; i++) {
  42                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  43                 if (val & ~0xff)
  44                         return -1;
  45                 *sha1++ = val;
  46                 hex += 2;
  47         }
  48         return 0;
  49 }
  50
  51 int safe_create_leading_directories(char *path)
  52 {
  53         char *pos = path;
  54         if (*pos == '/')
  55                 pos++;
  56
  57         while (pos) {
  58                 pos = strchr(pos, '/');
  59                 if (!pos)
  60                         break;
  61                 *pos = 0;
  62                 if (mkdir(path, 0777) < 0)
  63                         if (errno != EEXIST) {
  64                                 *pos = '/';
  65                                 return -1;
  66                         }
  67                 *pos++ = '/';
  68         }
  69         return 0;
  70 }
  71
  72 char * sha1_to_hex(const unsigned char *sha1)
  73 {
  74         static char buffer[50];
  75         static const char hex[] = "0123456789abcdef";
  76         char *buf = buffer;
  77         int i;
  78
  79         for (i = 0; i < 20; i++) {
  80                 unsigned int val = *sha1++;
  81                 *buf++ = hex[val >> 4];
  82                 *buf++ = hex[val & 0xf];
  83         }
  84         return buffer;
  85 }
  86
  87 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
  88 {
  89         int i;
  90         for (i = 0; i < 20; i++) {
  91                 static char hex[] = "0123456789abcdef";
  92                 unsigned int val = sha1[i];
  93                 char *pos = pathbuf + i*2 + (i > 0);
  94                 *pos++ = hex[val >> 4];
  95                 *pos = hex[val & 0xf];
  96         }
  97 }
  98
  99 /*
 100  * NOTE! This returns a statically allocated buffer, so you have to be
 101  * careful about using it. Do a "strdup()" if you need to save the
 102  * filename.
 103  *
 104  * Also note that this returns the location for creating.  Reading
 105  * SHA1 file can happen from any alternate directory listed in the
 106  * DB_ENVIRONMENT environment variable if it is not found in
 107  * the primary object database.
 108  */
 109 char *sha1_file_name(const unsigned char *sha1)
 110 {
 111         static char *name, *base;
 112
 113         if (!base) {
 114                 const char *sha1_file_directory = get_object_directory();
 115                 int len = strlen(sha1_file_directory);
 116                 base = xmalloc(len + 60);
 117                 memcpy(base, sha1_file_directory, len);
 118                 memset(base+len, 0, 60);
 119                 base[len] = '/';
 120                 base[len+3] = '/';
 121                 name = base + len + 1;
 122         }
 123         fill_sha1_path(name, sha1);
 124         return base;
 125 }
 126
 127 char *sha1_pack_name(const unsigned char *sha1)
 128 {
 129         static const char hex[] = "0123456789abcdef";
 130         static char *name, *base, *buf;
 131         int i;
 132
 133         if (!base) {
 134                 const char *sha1_file_directory = get_object_directory();
 135                 int len = strlen(sha1_file_directory);
 136                 base = xmalloc(len + 60);
 137                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 138                 name = base + len + 11;
 139         }
 140
 141         buf = name;
 142
 143         for (i = 0; i < 20; i++) {
 144                 unsigned int val = *sha1++;
 145                 *buf++ = hex[val >> 4];
 146                 *buf++ = hex[val & 0xf];
 147         }
 148
 149         return base;
 150 }
 151
 152 char *sha1_pack_index_name(const unsigned char *sha1)
 153 {
 154         static const char hex[] = "0123456789abcdef";
 155         static char *name, *base, *buf;
 156         int i;
 157
 158         if (!base) {
 159                 const char *sha1_file_directory = get_object_directory();
 160                 int len = strlen(sha1_file_directory);
 161                 base = xmalloc(len + 60);
 162                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 163                 name = base + len + 11;
 164         }
 165
 166         buf = name;
 167
 168         for (i = 0; i < 20; i++) {
 169                 unsigned int val = *sha1++;
 170                 *buf++ = hex[val >> 4];
 171                 *buf++ = hex[val & 0xf];
 172         }
 173
 174         return base;
 175 }
 176
 177 struct alternate_object_database *alt_odb_list;
 178 static struct alternate_object_database **alt_odb_tail;
 179
 180 /*
 181  * Prepare alternate object database registry.
 182  *
 183  * The variable alt_odb_list points at the list of struct
 184  * alternate_object_database.  The elements on this list come from
 185  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 186  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 187  * whose contents is exactly in the same format as that environment
 188  * variable.  Its base points at a statically allocated buffer that
 189  * contains "/the/directory/corresponding/to/.git/objects/...", while
 190  * its name points just after the slash at the end of ".git/objects/"
 191  * in the example above, and has enough space to hold 40-byte hex
 192  * SHA1, an extra slash for the first level indirection, and the
 193  * terminating NUL.
 194  */
 195 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 196                                  const char *relative_base)
 197 {
 198         const char *cp, *last;
 199         struct alternate_object_database *ent;
 200         int base_len = -1;
 201
 202         last = alt;
 203         while (last < ep) {
 204                 cp = last;
 205                 if (cp < ep && *cp == '#') {
 206                         while (cp < ep && *cp != sep)
 207                                 cp++;
 208                         last = cp + 1;
 209                         continue;
 210                 }
 211                 for ( ; cp < ep && *cp != sep; cp++)
 212                         ;
 213                 if (last != cp) {
 214                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 215                         int pfxlen = cp - last;
 216                         int entlen = pfxlen + 43;
 217
 218                         if (*last != '/' && relative_base) {
 219                                 /* Relative alt-odb */
 220                                 if (base_len < 0)
 221                                         base_len = strlen(relative_base) + 1;
 222                                 entlen += base_len;
 223                                 pfxlen += base_len;
 224                         }
 225                         ent = xmalloc(sizeof(*ent) + entlen);
 226                         *alt_odb_tail = ent;
 227                         alt_odb_tail = &(ent->next);
 228                         ent->next = NULL;
 229                         if (*last != '/' && relative_base) {
 230                                 memcpy(ent->base, relative_base, base_len - 1);
 231                                 ent->base[base_len - 1] = '/';
 232                                 memcpy(ent->base + base_len,
 233                                        last, cp - last);
 234                         }
 235                         else
 236                                 memcpy(ent->base, last, pfxlen);
 237                         ent->name = ent->base + pfxlen + 1;
 238                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 239                         ent->base[entlen-1] = 0;
 240                 }
 241                 while (cp < ep && *cp == sep)
 242                         cp++;
 243                 last = cp;
 244         }
 245 }
 246
 247 void prepare_alt_odb(void)
 248 {
 249         char path[PATH_MAX];
 250         char *map;
 251         int fd;
 252         struct stat st;
 253         char *alt;
 254
 255         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 256         if (!alt) alt = "";
 257
 258         if (alt_odb_tail)
 259                 return;
 260         alt_odb_tail = &alt_odb_list;
 261         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 262
 263         sprintf(path, "%s/info/alternates", get_object_directory());
 264         fd = open(path, O_RDONLY);
 265         if (fd < 0)
 266                 return;
 267         if (fstat(fd, &st) || (st.st_size == 0)) {
 268                 close(fd);
 269                 return;
 270         }
 271         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 272         close(fd);
 273         if (map == MAP_FAILED)
 274                 return;
 275
 276         link_alt_odb_entries(map, map + st.st_size, '\n',
 277                              get_object_directory());
 278         munmap(map, st.st_size);
 279 }
 280
 281 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 282 {
 283         char *name = sha1_file_name(sha1);
 284         struct alternate_object_database *alt;
 285
 286         if (!stat(name, st))
 287                 return name;
 288         prepare_alt_odb();
 289         for (alt = alt_odb_list; alt; alt = alt->next) {
 290                 name = alt->name;
 291                 fill_sha1_path(name, sha1);
 292                 if (!stat(alt->base, st))
 293                         return alt->base;
 294         }
 295         return NULL;
 296 }
 297
 298 #define PACK_MAX_SZ (1<<26)
 299 static int pack_used_ctr;
 300 static unsigned long pack_mapped;
 301 struct packed_git *packed_git;
 302
 303 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 304                                 void **idx_map_)
 305 {
 306         void *idx_map;
 307         unsigned int *index;
 308         unsigned long idx_size;
 309         int nr, i;
 310         int fd = open(path, O_RDONLY);
 311         struct stat st;
 312         if (fd < 0)
 313                 return -1;
 314         if (fstat(fd, &st)) {
 315                 close(fd);
 316                 return -1;
 317         }
 318         idx_size = st.st_size;
 319         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 320         close(fd);
 321         if (idx_map == MAP_FAILED)
 322                 return -1;
 323
 324         index = idx_map;
 325         *idx_map_ = idx_map;
 326         *idx_size_ = idx_size;
 327
 328         /* check index map */
 329         if (idx_size < 4*256 + 20 + 20)
 330                 return error("index file too small");
 331         nr = 0;
 332         for (i = 0; i < 256; i++) {
 333                 unsigned int n = ntohl(index[i]);
 334                 if (n < nr)
 335                         return error("non-monotonic index");
 336                 nr = n;
 337         }
 338
 339         /*
 340          * Total size:
 341          *  - 256 index entries 4 bytes each
 342          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 343          *  - 20-byte SHA1 of the packfile
 344          *  - 20-byte SHA1 file checksum
 345          */
 346         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 347                 return error("wrong index file size");
 348
 349         return 0;
 350 }
 351
 352 static int unuse_one_packed_git(void)
 353 {
 354         struct packed_git *p, *lru = NULL;
 355
 356         for (p = packed_git; p; p = p->next) {
 357                 if (p->pack_use_cnt || !p->pack_base)
 358                         continue;
 359                 if (!lru || p->pack_last_used < lru->pack_last_used)
 360                         lru = p;
 361         }
 362         if (!lru)
 363                 return 0;
 364         munmap(lru->pack_base, lru->pack_size);
 365         lru->pack_base = NULL;
 366         return 1;
 367 }
 368
 369 void unuse_packed_git(struct packed_git *p)
 370 {
 371         p->pack_use_cnt--;
 372 }
 373
 374 int use_packed_git(struct packed_git *p)
 375 {
 376         if (!p->pack_size) {
 377                 struct stat st;
 378                 // We created the struct before we had the pack
 379                 stat(p->pack_name, &st);
 380                 if (!S_ISREG(st.st_mode))
 381                         die("packfile %s not a regular file", p->pack_name);
 382                 p->pack_size = st.st_size;
 383         }
 384         if (!p->pack_base) {
 385                 int fd;
 386                 struct stat st;
 387                 void *map;
 388
 389                 pack_mapped += p->pack_size;
 390                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 391                         ; /* nothing */
 392                 fd = open(p->pack_name, O_RDONLY);
 393                 if (fd < 0)
 394                         die("packfile %s cannot be opened", p->pack_name);
 395                 if (fstat(fd, &st)) {
 396                         close(fd);
 397                         die("packfile %s cannot be opened", p->pack_name);
 398                 }
 399                 if (st.st_size != p->pack_size)
 400                         die("packfile %s size mismatch.", p->pack_name);
 401                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 402                 close(fd);
 403                 if (map == MAP_FAILED)
 404                         die("packfile %s cannot be mapped.", p->pack_name);
 405                 p->pack_base = map;
 406
 407                 /* Check if the pack file matches with the index file.
 408                  * this is cheap.
 409                  */
 410                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 411                            p->pack_base + p->pack_size - 20, 20)) {
 412
 413                         die("packfile %s does not match index.", p->pack_name);
 414                 }
 415         }
 416         p->pack_last_used = pack_used_ctr++;
 417         p->pack_use_cnt++;
 418         return 0;
 419 }
 420
 421 struct packed_git *add_packed_git(char *path, int path_len, int local)
 422 {
 423         struct stat st;
 424         struct packed_git *p;
 425         unsigned long idx_size;
 426         void *idx_map;
 427         unsigned char sha1[20];
 428
 429         if (check_packed_git_idx(path, &idx_size, &idx_map))
 430                 return NULL;
 431
 432         /* do we have a corresponding .pack file? */
 433         strcpy(path + path_len - 4, ".pack");
 434         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 435                 munmap(idx_map, idx_size);
 436                 return NULL;
 437         }
 438         /* ok, it looks sane as far as we can check without
 439          * actually mapping the pack file.
 440          */
 441         p = xmalloc(sizeof(*p) + path_len + 2);
 442         strcpy(p->pack_name, path);
 443         p->index_size = idx_size;
 444         p->pack_size = st.st_size;
 445         p->index_base = idx_map;
 446         p->next = NULL;
 447         p->pack_base = NULL;
 448         p->pack_last_used = 0;
 449         p->pack_use_cnt = 0;
 450         p->pack_local = local;
 451         if (!get_sha1_hex(path + path_len - 40 - 4, sha1))
 452                 memcpy(p->sha1, sha1, 20);
 453         return p;
 454 }
 455
 456 struct packed_git *parse_pack_index(unsigned char *sha1)
 457 {
 458         char *path = sha1_pack_index_name(sha1);
 459         return parse_pack_index_file(sha1, path);
 460 }
 461
 462 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 463 {
 464         struct packed_git *p;
 465         unsigned long idx_size;
 466         void *idx_map;
 467         char *path;
 468
 469         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 470                 return NULL;
 471
 472         path = sha1_pack_name(sha1);
 473
 474         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 475         strcpy(p->pack_name, path);
 476         p->index_size = idx_size;
 477         p->pack_size = 0;
 478         p->index_base = idx_map;
 479         p->next = NULL;
 480         p->pack_base = NULL;
 481         p->pack_last_used = 0;
 482         p->pack_use_cnt = 0;
 483         memcpy(p->sha1, sha1, 20);
 484         return p;
 485 }
 486
 487 void install_packed_git(struct packed_git *pack)
 488 {
 489         pack->next = packed_git;
 490         packed_git = pack;
 491 }
 492
 493 static void prepare_packed_git_one(char *objdir, int local)
 494 {
 495         char path[PATH_MAX];
 496         int len;
 497         DIR *dir;
 498         struct dirent *de;
 499
 500         sprintf(path, "%s/pack", objdir);
 501         len = strlen(path);
 502         dir = opendir(path);
 503         if (!dir)
 504                 return;
 505         path[len++] = '/';
 506         while ((de = readdir(dir)) != NULL) {
 507                 int namelen = strlen(de->d_name);
 508                 struct packed_git *p;
 509
 510                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 511                         continue;
 512
 513                 /* we have .idx.  Is it a file we can map? */
 514                 strcpy(path + len, de->d_name);
 515                 p = add_packed_git(path, len + namelen, local);
 516                 if (!p)
 517                         continue;
 518                 p->next = packed_git;
 519                 packed_git = p;
 520         }
 521         closedir(dir);
 522 }
 523
 524 void prepare_packed_git(void)
 525 {
 526         static int run_once = 0;
 527         struct alternate_object_database *alt;
 528
 529         if (run_once)
 530                 return;
 531         prepare_packed_git_one(get_object_directory(), 1);
 532         prepare_alt_odb();
 533         for (alt = alt_odb_list; alt; alt = alt->next) {
 534                 alt->name[0] = 0;
 535                 prepare_packed_git_one(alt->base, 0);
 536         }
 537         run_once = 1;
 538 }
 539
 540 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 541 {
 542         char header[100];
 543         unsigned char real_sha1[20];
 544         SHA_CTX c;
 545
 546         SHA1_Init(&c);
 547         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 548         SHA1_Update(&c, map, size);
 549         SHA1_Final(real_sha1, &c);
 550         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 551 }
 552
 553 static void *map_sha1_file_internal(const unsigned char *sha1,
 554                                     unsigned long *size)
 555 {
 556         struct stat st;
 557         void *map;
 558         int fd;
 559         char *filename = find_sha1_file(sha1, &st);
 560
 561         if (!filename) {
 562                 return NULL;
 563         }
 564
 565         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 566         if (fd < 0) {
 567                 /* See if it works without O_NOATIME */
 568                 switch (sha1_file_open_flag) {
 569                 default:
 570                         fd = open(filename, O_RDONLY);
 571                         if (fd >= 0)
 572                                 break;
 573                 /* Fallthrough */
 574                 case 0:
 575                         return NULL;
 576                 }
 577
 578                 /* If it failed once, it will probably fail again.
 579                  * Stop using O_NOATIME
 580                  */
 581                 sha1_file_open_flag = 0;
 582         }
 583         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 584         close(fd);
 585         if (map == MAP_FAILED)
 586                 return NULL;
 587         *size = st.st_size;
 588         return map;
 589 }
 590
 591 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 592 {
 593         /* Get the data stream */
 594         memset(stream, 0, sizeof(*stream));
 595         stream->next_in = map;
 596         stream->avail_in = mapsize;
 597         stream->next_out = buffer;
 598         stream->avail_out = size;
 599
 600         inflateInit(stream);
 601         return inflate(stream, 0);
 602 }
 603
 604 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 605 {
 606         int bytes = strlen(buffer) + 1;
 607         unsigned char *buf = xmalloc(1+size);
 608
 609         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 610         bytes = stream->total_out - bytes;
 611         if (bytes < size) {
 612                 stream->next_out = buf + bytes;
 613                 stream->avail_out = size - bytes;
 614                 while (inflate(stream, Z_FINISH) == Z_OK)
 615                         /* nothing */;
 616         }
 617         buf[size] = 0;
 618         inflateEnd(stream);
 619         return buf;
 620 }
 621
 622 /*
 623  * We used to just use "sscanf()", but that's actually way
 624  * too permissive for what we want to check. So do an anal
 625  * object header parse by hand.
 626  */
 627 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 628 {
 629         int i;
 630         unsigned long size;
 631
 632         /*
 633          * The type can be at most ten bytes (including the
 634          * terminating '\0' that we add), and is followed by
 635          * a space.
 636          */
 637         i = 10;
 638         for (;;) {
 639                 char c = *hdr++;
 640                 if (c == ' ')
 641                         break;
 642                 if (!--i)
 643                         return -1;
 644                 *type++ = c;
 645         }
 646         *type = 0;
 647
 648         /*
 649          * The length must follow immediately, and be in canonical
 650          * decimal format (ie "010" is not valid).
 651          */
 652         size = *hdr++ - '0';
 653         if (size > 9)
 654                 return -1;
 655         if (size) {
 656                 for (;;) {
 657                         unsigned long c = *hdr - '0';
 658                         if (c > 9)
 659                                 break;
 660                         hdr++;
 661                         size = size * 10 + c;
 662                 }
 663         }
 664         *sizep = size;
 665
 666         /*
 667          * The length must be followed by a zero byte
 668          */
 669         return *hdr ? -1 : 0;
 670 }
 671
 672 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 673 {
 674         int ret;
 675         z_stream stream;
 676         char hdr[8192];
 677
 678         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 679         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 680                 return NULL;
 681
 682         return unpack_sha1_rest(&stream, hdr, *size);
 683 }
 684
 685 /* forward declaration for a mutually recursive function */
 686 static int packed_object_info(struct pack_entry *entry,
 687                               char *type, unsigned long *sizep);
 688
 689 static int packed_delta_info(unsigned char *base_sha1,
 690                              unsigned long delta_size,
 691                              unsigned long left,
 692                              char *type,
 693                              unsigned long *sizep,
 694                              struct packed_git *p)
 695 {
 696         struct pack_entry base_ent;
 697
 698         if (left < 20)
 699                 die("truncated pack file");
 700
 701         /* The base entry _must_ be in the same pack */
 702         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 703                 die("failed to find delta-pack base object %s",
 704                     sha1_to_hex(base_sha1));
 705
 706         /* We choose to only get the type of the base object and
 707          * ignore potentially corrupt pack file that expects the delta
 708          * based on a base with a wrong size.  This saves tons of
 709          * inflate() calls.
 710          */
 711
 712         if (packed_object_info(&base_ent, type, NULL))
 713                 die("cannot get info for delta-pack base");
 714
 715         if (sizep) {
 716                 const unsigned char *data;
 717                 unsigned char delta_head[64];
 718                 unsigned long result_size;
 719                 z_stream stream;
 720                 int st;
 721
 722                 memset(&stream, 0, sizeof(stream));
 723
 724                 data = stream.next_in = base_sha1 + 20;
 725                 stream.avail_in = left - 20;
 726                 stream.next_out = delta_head;
 727                 stream.avail_out = sizeof(delta_head);
 728
 729                 inflateInit(&stream);
 730                 st = inflate(&stream, Z_FINISH);
 731                 inflateEnd(&stream);
 732                 if ((st != Z_STREAM_END) &&
 733                     stream.total_out != sizeof(delta_head))
 734                         die("delta data unpack-initial failed");
 735
 736                 /* Examine the initial part of the delta to figure out
 737                  * the result size.
 738                  */
 739                 data = delta_head;
 740                 get_delta_hdr_size(&data); /* ignore base size */
 741
 742                 /* Read the result size */
 743                 result_size = get_delta_hdr_size(&data);
 744                 *sizep = result_size;
 745         }
 746         return 0;
 747 }
 748
 749 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 750         enum object_type *type, unsigned long *sizep)
 751 {
 752         unsigned shift;
 753         unsigned char *pack, c;
 754         unsigned long size;
 755
 756         if (offset >= p->pack_size)
 757                 die("object offset outside of pack file");
 758
 759         pack =  p->pack_base + offset;
 760         c = *pack++;
 761         offset++;
 762         *type = (c >> 4) & 7;
 763         size = c & 15;
 764         shift = 4;
 765         while (c & 0x80) {
 766                 if (offset >= p->pack_size)
 767                         die("object offset outside of pack file");
 768                 c = *pack++;
 769                 offset++;
 770                 size += (c & 0x7f) << shift;
 771                 shift += 7;
 772         }
 773         *sizep = size;
 774         return offset;
 775 }
 776
 777 void packed_object_info_detail(struct pack_entry *e,
 778                                char *type,
 779                                unsigned long *size,
 780                                unsigned long *store_size,
 781                                int *delta_chain_length,
 782                                unsigned char *base_sha1)
 783 {
 784         struct packed_git *p = e->p;
 785         unsigned long offset, left;
 786         unsigned char *pack;
 787         enum object_type kind;
 788
 789         offset = unpack_object_header(p, e->offset, &kind, size);
 790         pack = p->pack_base + offset;
 791         left = p->pack_size - offset;
 792         if (kind != OBJ_DELTA)
 793                 *delta_chain_length = 0;
 794         else {
 795                 int chain_length = 0;
 796                 memcpy(base_sha1, pack, 20);
 797                 do {
 798                         struct pack_entry base_ent;
 799                         unsigned long junk;
 800
 801                         find_pack_entry_one(pack, &base_ent, p);
 802                         offset = unpack_object_header(p, base_ent.offset,
 803                                                       &kind, &junk);
 804                         pack = p->pack_base + offset;
 805                         chain_length++;
 806                 } while (kind == OBJ_DELTA);
 807                 *delta_chain_length = chain_length;
 808         }
 809         switch (kind) {
 810         case OBJ_COMMIT:
 811                 strcpy(type, "commit");
 812                 break;
 813         case OBJ_TREE:
 814                 strcpy(type, "tree");
 815                 break;
 816         case OBJ_BLOB:
 817                 strcpy(type, "blob");
 818                 break;
 819         case OBJ_TAG:
 820                 strcpy(type, "tag");
 821                 break;
 822         default:
 823                 die("corrupted pack file %s containing object of kind %d",
 824                     p->pack_name, kind);
 825         }
 826         *store_size = 0; /* notyet */
 827 }
 828
 829 static int packed_object_info(struct pack_entry *entry,
 830                               char *type, unsigned long *sizep)
 831 {
 832         struct packed_git *p = entry->p;
 833         unsigned long offset, size, left;
 834         unsigned char *pack;
 835         enum object_type kind;
 836         int retval;
 837
 838         if (use_packed_git(p))
 839                 die("cannot map packed file");
 840
 841         offset = unpack_object_header(p, entry->offset, &kind, &size);
 842         pack = p->pack_base + offset;
 843         left = p->pack_size - offset;
 844
 845         switch (kind) {
 846         case OBJ_DELTA:
 847                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 848                 unuse_packed_git(p);
 849                 return retval;
 850         case OBJ_COMMIT:
 851                 strcpy(type, "commit");
 852                 break;
 853         case OBJ_TREE:
 854                 strcpy(type, "tree");
 855                 break;
 856         case OBJ_BLOB:
 857                 strcpy(type, "blob");
 858                 break;
 859         case OBJ_TAG:
 860                 strcpy(type, "tag");
 861                 break;
 862         default:
 863                 die("corrupted pack file %s containing object of kind %d",
 864                     p->pack_name, kind);
 865         }
 866         if (sizep)
 867                 *sizep = size;
 868         unuse_packed_git(p);
 869         return 0;
 870 }
 871
 872 /* forward declaration for a mutually recursive function */
 873 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 874
 875 static void *unpack_delta_entry(unsigned char *base_sha1,
 876                                 unsigned long delta_size,
 877                                 unsigned long left,
 878                                 char *type,
 879                                 unsigned long *sizep,
 880                                 struct packed_git *p)
 881 {
 882         struct pack_entry base_ent;
 883         void *data, *delta_data, *result, *base;
 884         unsigned long data_size, result_size, base_size;
 885         z_stream stream;
 886         int st;
 887
 888         if (left < 20)
 889                 die("truncated pack file");
 890         data = base_sha1 + 20;
 891         data_size = left - 20;
 892         delta_data = xmalloc(delta_size);
 893
 894         memset(&stream, 0, sizeof(stream));
 895
 896         stream.next_in = data;
 897         stream.avail_in = data_size;
 898         stream.next_out = delta_data;
 899         stream.avail_out = delta_size;
 900
 901         inflateInit(&stream);
 902         st = inflate(&stream, Z_FINISH);
 903         inflateEnd(&stream);
 904         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 905                 die("delta data unpack failed");
 906
 907         /* The base entry _must_ be in the same pack */
 908         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 909                 die("failed to find delta-pack base object %s",
 910                     sha1_to_hex(base_sha1));
 911         base = unpack_entry_gently(&base_ent, type, &base_size);
 912         if (!base)
 913                 die("failed to read delta-pack base object %s",
 914                     sha1_to_hex(base_sha1));
 915         result = patch_delta(base, base_size,
 916                              delta_data, delta_size,
 917                              &result_size);
 918         if (!result)
 919                 die("failed to apply delta");
 920         free(delta_data);
 921         free(base);
 922         *sizep = result_size;
 923         return result;
 924 }
 925
 926 static void *unpack_non_delta_entry(unsigned char *data,
 927                                     unsigned long size,
 928                                     unsigned long left)
 929 {
 930         int st;
 931         z_stream stream;
 932         unsigned char *buffer;
 933
 934         buffer = xmalloc(size + 1);
 935         buffer[size] = 0;
 936         memset(&stream, 0, sizeof(stream));
 937         stream.next_in = data;
 938         stream.avail_in = left;
 939         stream.next_out = buffer;
 940         stream.avail_out = size;
 941
 942         inflateInit(&stream);
 943         st = inflate(&stream, Z_FINISH);
 944         inflateEnd(&stream);
 945         if ((st != Z_STREAM_END) || stream.total_out != size) {
 946                 free(buffer);
 947                 return NULL;
 948         }
 949
 950         return buffer;
 951 }
 952
 953 static void *unpack_entry(struct pack_entry *entry,
 954                           char *type, unsigned long *sizep)
 955 {
 956         struct packed_git *p = entry->p;
 957         void *retval;
 958
 959         if (use_packed_git(p))
 960                 die("cannot map packed file");
 961         retval = unpack_entry_gently(entry, type, sizep);
 962         unuse_packed_git(p);
 963         if (!retval)
 964                 die("corrupted pack file %s", p->pack_name);
 965         return retval;
 966 }
 967
 968 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 969 void *unpack_entry_gently(struct pack_entry *entry,
 970                           char *type, unsigned long *sizep)
 971 {
 972         struct packed_git *p = entry->p;
 973         unsigned long offset, size, left;
 974         unsigned char *pack;
 975         enum object_type kind;
 976         void *retval;
 977
 978         offset = unpack_object_header(p, entry->offset, &kind, &size);
 979         pack = p->pack_base + offset;
 980         left = p->pack_size - offset;
 981         switch (kind) {
 982         case OBJ_DELTA:
 983                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
 984                 return retval;
 985         case OBJ_COMMIT:
 986                 strcpy(type, "commit");
 987                 break;
 988         case OBJ_TREE:
 989                 strcpy(type, "tree");
 990                 break;
 991         case OBJ_BLOB:
 992                 strcpy(type, "blob");
 993                 break;
 994         case OBJ_TAG:
 995                 strcpy(type, "tag");
 996                 break;
 997         default:
 998                 return NULL;
 999         }
1000         *sizep = size;
1001         retval = unpack_non_delta_entry(pack, size, left);
1002         return retval;
1003 }
1004
1005 int num_packed_objects(const struct packed_git *p)
1006 {
1007         /* See check_packed_git_idx() */
1008         return (p->index_size - 20 - 20 - 4*256) / 24;
1009 }
1010
1011 int nth_packed_object_sha1(const struct packed_git *p, int n,
1012                            unsigned char* sha1)
1013 {
1014         void *index = p->index_base + 256;
1015         if (n < 0 || num_packed_objects(p) <= n)
1016                 return -1;
1017         memcpy(sha1, (index + 24 * n + 4), 20);
1018         return 0;
1019 }
1020
1021 int find_pack_entry_one(const unsigned char *sha1,
1022                         struct pack_entry *e, struct packed_git *p)
1023 {
1024         unsigned int *level1_ofs = p->index_base;
1025         int hi = ntohl(level1_ofs[*sha1]);
1026         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1027         void *index = p->index_base + 256;
1028
1029         do {
1030                 int mi = (lo + hi) / 2;
1031                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1032                 if (!cmp) {
1033                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1034                         memcpy(e->sha1, sha1, 20);
1035                         e->p = p;
1036                         return 1;
1037                 }
1038                 if (cmp > 0)
1039                         hi = mi;
1040                 else
1041                         lo = mi+1;
1042         } while (lo < hi);
1043         return 0;
1044 }
1045
1046 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1047 {
1048         struct packed_git *p;
1049         prepare_packed_git();
1050
1051         for (p = packed_git; p; p = p->next) {
1052                 if (find_pack_entry_one(sha1, e, p))
1053                         return 1;
1054         }
1055         return 0;
1056 }
1057
1058 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1059                                   struct packed_git *packs)
1060 {
1061         struct packed_git *p;
1062         struct pack_entry e;
1063
1064         for (p = packs; p; p = p->next) {
1065                 if (find_pack_entry_one(sha1, &e, p))
1066                         return p;
1067         }
1068         return NULL;
1069
1070 }
1071
1072 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1073 {
1074         int status;
1075         unsigned long mapsize, size;
1076         void *map;
1077         z_stream stream;
1078         char hdr[128];
1079
1080         map = map_sha1_file_internal(sha1, &mapsize);
1081         if (!map) {
1082                 struct pack_entry e;
1083
1084                 if (!find_pack_entry(sha1, &e))
1085                         return error("unable to find %s", sha1_to_hex(sha1));
1086                 return packed_object_info(&e, type, sizep);
1087         }
1088         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1089                 status = error("unable to unpack %s header",
1090                                sha1_to_hex(sha1));
1091         if (parse_sha1_header(hdr, type, &size) < 0)
1092                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1093         else {
1094                 status = 0;
1095                 if (sizep)
1096                         *sizep = size;
1097         }
1098         inflateEnd(&stream);
1099         munmap(map, mapsize);
1100         return status;
1101 }
1102
1103 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1104 {
1105         struct pack_entry e;
1106
1107         if (!find_pack_entry(sha1, &e)) {
1108                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1109                 return NULL;
1110         }
1111         return unpack_entry(&e, type, size);
1112 }
1113
1114 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1115 {
1116         unsigned long mapsize;
1117         void *map, *buf;
1118         struct pack_entry e;
1119
1120         if (find_pack_entry(sha1, &e))
1121                 return read_packed_sha1(sha1, type, size);
1122         map = map_sha1_file_internal(sha1, &mapsize);
1123         if (map) {
1124                 buf = unpack_sha1_file(map, mapsize, type, size);
1125                 munmap(map, mapsize);
1126                 return buf;
1127         }
1128         return NULL;
1129 }
1130
1131 void *read_object_with_reference(const unsigned char *sha1,
1132                                  const char *required_type,
1133                                  unsigned long *size,
1134                                  unsigned char *actual_sha1_return)
1135 {
1136         char type[20];
1137         void *buffer;
1138         unsigned long isize;
1139         unsigned char actual_sha1[20];
1140
1141         memcpy(actual_sha1, sha1, 20);
1142         while (1) {
1143                 int ref_length = -1;
1144                 const char *ref_type = NULL;
1145
1146                 buffer = read_sha1_file(actual_sha1, type, &isize);
1147                 if (!buffer)
1148                         return NULL;
1149                 if (!strcmp(type, required_type)) {
1150                         *size = isize;
1151                         if (actual_sha1_return)
1152                                 memcpy(actual_sha1_return, actual_sha1, 20);
1153                         return buffer;
1154                 }
1155                 /* Handle references */
1156                 else if (!strcmp(type, "commit"))
1157                         ref_type = "tree ";
1158                 else if (!strcmp(type, "tag"))
1159                         ref_type = "object ";
1160                 else {
1161                         free(buffer);
1162                         return NULL;
1163                 }
1164                 ref_length = strlen(ref_type);
1165
1166                 if (memcmp(buffer, ref_type, ref_length) ||
1167                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1168                         free(buffer);
1169                         return NULL;
1170                 }
1171                 free(buffer);
1172                 /* Now we have the ID of the referred-to object in
1173                  * actual_sha1.  Check again. */
1174         }
1175 }
1176
1177 char *write_sha1_file_prepare(void *buf,
1178                               unsigned long len,
1179                               const char *type,
1180                               unsigned char *sha1,
1181                               unsigned char *hdr,
1182                               int *hdrlen)
1183 {
1184         SHA_CTX c;
1185
1186         /* Generate the header */
1187         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1188
1189         /* Sha1.. */
1190         SHA1_Init(&c);
1191         SHA1_Update(&c, hdr, *hdrlen);
1192         SHA1_Update(&c, buf, len);
1193         SHA1_Final(sha1, &c);
1194
1195         return sha1_file_name(sha1);
1196 }
1197
1198 /*
1199  * Link the tempfile to the final place, possibly creating the
1200  * last directory level as you do so.
1201  *
1202  * Returns the errno on failure, 0 on success.
1203  */
1204 static int link_temp_to_file(const char *tmpfile, char *filename)
1205 {
1206         int ret;
1207
1208         if (!link(tmpfile, filename))
1209                 return 0;
1210
1211         /*
1212          * Try to mkdir the last path component if that failed
1213          * with an ENOENT.
1214          *
1215          * Re-try the "link()" regardless of whether the mkdir
1216          * succeeds, since a race might mean that somebody
1217          * else succeeded.
1218          */
1219         ret = errno;
1220         if (ret == ENOENT) {
1221                 char *dir = strrchr(filename, '/');
1222                 if (dir) {
1223                         *dir = 0;
1224                         mkdir(filename, 0777);
1225                         *dir = '/';
1226                         if (!link(tmpfile, filename))
1227                                 return 0;
1228                         ret = errno;
1229                 }
1230         }
1231         return ret;
1232 }
1233
1234 /*
1235  * Move the just written object into its final resting place
1236  */
1237 int move_temp_to_file(const char *tmpfile, char *filename)
1238 {
1239         int ret = link_temp_to_file(tmpfile, filename);
1240
1241         /*
1242          * Coda hack - coda doesn't like cross-directory links,
1243          * so we fall back to a rename, which will mean that it
1244          * won't be able to check collisions, but that's not a
1245          * big deal.
1246          *
1247          * The same holds for FAT formatted media.
1248          *
1249          * When this succeeds, we just return 0. We have nothing
1250          * left to unlink.
1251          */
1252         if (ret && ret != EEXIST) {
1253                 if (!rename(tmpfile, filename))
1254                         return 0;
1255                 ret = errno;
1256         }
1257         unlink(tmpfile);
1258         if (ret) {
1259                 if (ret != EEXIST) {
1260                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1261                         return -1;
1262                 }
1263                 /* FIXME!!! Collision check here ? */
1264         }
1265
1266         return 0;
1267 }
1268
1269 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1270 {
1271         int size;
1272         unsigned char *compressed;
1273         z_stream stream;
1274         unsigned char sha1[20];
1275         char *filename;
1276         static char tmpfile[PATH_MAX];
1277         unsigned char hdr[50];
1278         int fd, hdrlen;
1279
1280         /* Normally if we have it in the pack then we do not bother writing
1281          * it out into .git/objects/??/?{38} file.
1282          */
1283         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1284         if (returnsha1)
1285                 memcpy(returnsha1, sha1, 20);
1286         if (has_sha1_file(sha1))
1287                 return 0;
1288         fd = open(filename, O_RDONLY);
1289         if (fd >= 0) {
1290                 /*
1291                  * FIXME!!! We might do collision checking here, but we'd
1292                  * need to uncompress the old file and check it. Later.
1293                  */
1294                 close(fd);
1295                 return 0;
1296         }
1297
1298         if (errno != ENOENT) {
1299                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1300                 return -1;
1301         }
1302
1303         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1304
1305         fd = mkstemp(tmpfile);
1306         if (fd < 0) {
1307                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1308                 return -1;
1309         }
1310
1311         /* Set it up */
1312         memset(&stream, 0, sizeof(stream));
1313         deflateInit(&stream, Z_BEST_COMPRESSION);
1314         size = deflateBound(&stream, len+hdrlen);
1315         compressed = xmalloc(size);
1316
1317         /* Compress it */
1318         stream.next_out = compressed;
1319         stream.avail_out = size;
1320
1321         /* First header.. */
1322         stream.next_in = hdr;
1323         stream.avail_in = hdrlen;
1324         while (deflate(&stream, 0) == Z_OK)
1325                 /* nothing */;
1326
1327         /* Then the data itself.. */
1328         stream.next_in = buf;
1329         stream.avail_in = len;
1330         while (deflate(&stream, Z_FINISH) == Z_OK)
1331                 /* nothing */;
1332         deflateEnd(&stream);
1333         size = stream.total_out;
1334
1335         if (write(fd, compressed, size) != size)
1336                 die("unable to write file");
1337         fchmod(fd, 0444);
1338         close(fd);
1339         free(compressed);
1340
1341         return move_temp_to_file(tmpfile, filename);
1342 }
1343
1344 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1345 {
1346         ssize_t size;
1347         unsigned long objsize;
1348         int posn = 0;
1349         void *map = map_sha1_file_internal(sha1, &objsize);
1350         void *buf = map;
1351         void *temp_obj = NULL;
1352         z_stream stream;
1353
1354         if (!buf) {
1355                 unsigned char *unpacked;
1356                 unsigned long len;
1357                 char type[20];
1358                 char hdr[50];
1359                 int hdrlen;
1360                 // need to unpack and recompress it by itself
1361                 unpacked = read_packed_sha1(sha1, type, &len);
1362
1363                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1364
1365                 /* Set it up */
1366                 memset(&stream, 0, sizeof(stream));
1367                 deflateInit(&stream, Z_BEST_COMPRESSION);
1368                 size = deflateBound(&stream, len + hdrlen);
1369                 temp_obj = buf = xmalloc(size);
1370
1371                 /* Compress it */
1372                 stream.next_out = buf;
1373                 stream.avail_out = size;
1374
1375                 /* First header.. */
1376                 stream.next_in = (void *)hdr;
1377                 stream.avail_in = hdrlen;
1378                 while (deflate(&stream, 0) == Z_OK)
1379                         /* nothing */;
1380
1381                 /* Then the data itself.. */
1382                 stream.next_in = unpacked;
1383                 stream.avail_in = len;
1384                 while (deflate(&stream, Z_FINISH) == Z_OK)
1385                         /* nothing */;
1386                 deflateEnd(&stream);
1387                 free(unpacked);
1388
1389                 objsize = stream.total_out;
1390         }
1391
1392         do {
1393                 size = write(fd, buf + posn, objsize - posn);
1394                 if (size <= 0) {
1395                         if (!size) {
1396                                 fprintf(stderr, "write closed");
1397                         } else {
1398                                 perror("write ");
1399                         }
1400                         return -1;
1401                 }
1402                 posn += size;
1403         } while (posn < objsize);
1404
1405         if (map)
1406                 munmap(map, objsize);
1407         if (temp_obj)
1408                 free(temp_obj);
1409
1410         return 0;
1411 }
1412
1413 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1414                        size_t bufsize, size_t *bufposn)
1415 {
1416         char tmpfile[PATH_MAX];
1417         int local;
1418         z_stream stream;
1419         unsigned char real_sha1[20];
1420         unsigned char discard[4096];
1421         int ret;
1422         SHA_CTX c;
1423
1424         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1425
1426         local = mkstemp(tmpfile);
1427         if (local < 0)
1428                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1429
1430         memset(&stream, 0, sizeof(stream));
1431
1432         inflateInit(&stream);
1433
1434         SHA1_Init(&c);
1435
1436         do {
1437                 ssize_t size;
1438                 if (*bufposn) {
1439                         stream.avail_in = *bufposn;
1440                         stream.next_in = (unsigned char *) buffer;
1441                         do {
1442                                 stream.next_out = discard;
1443                                 stream.avail_out = sizeof(discard);
1444                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1445                                 SHA1_Update(&c, discard, sizeof(discard) -
1446                                             stream.avail_out);
1447                         } while (stream.avail_in && ret == Z_OK);
1448                         write(local, buffer, *bufposn - stream.avail_in);
1449                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1450                                 stream.avail_in);
1451                         *bufposn = stream.avail_in;
1452                         if (ret != Z_OK)
1453                                 break;
1454                 }
1455                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1456                 if (size <= 0) {
1457                         close(local);
1458                         unlink(tmpfile);
1459                         if (!size)
1460                                 return error("Connection closed?");
1461                         perror("Reading from connection");
1462                         return -1;
1463                 }
1464                 *bufposn += size;
1465         } while (1);
1466         inflateEnd(&stream);
1467
1468         close(local);
1469         SHA1_Final(real_sha1, &c);
1470         if (ret != Z_STREAM_END) {
1471                 unlink(tmpfile);
1472                 return error("File %s corrupted", sha1_to_hex(sha1));
1473         }
1474         if (memcmp(sha1, real_sha1, 20)) {
1475                 unlink(tmpfile);
1476                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1477         }
1478
1479         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1480 }
1481
1482 int has_pack_index(const unsigned char *sha1)
1483 {
1484         struct stat st;
1485         if (stat(sha1_pack_index_name(sha1), &st))
1486                 return 0;
1487         return 1;
1488 }
1489
1490 int has_pack_file(const unsigned char *sha1)
1491 {
1492         struct stat st;
1493         if (stat(sha1_pack_name(sha1), &st))
1494                 return 0;
1495         return 1;
1496 }
1497
1498 int has_sha1_pack(const unsigned char *sha1)
1499 {
1500         struct pack_entry e;
1501         return find_pack_entry(sha1, &e);
1502 }
1503
1504 int has_sha1_file(const unsigned char *sha1)
1505 {
1506         struct stat st;
1507         struct pack_entry e;
1508
1509         if (find_pack_entry(sha1, &e))
1510                 return 1;
1511         return find_sha1_file(sha1, &st) ? 1 : 0;
1512 }
1513
1514 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1515 {
1516         unsigned long size = st->st_size;
1517         void *buf;
1518         int ret;
1519         unsigned char hdr[50];
1520         int hdrlen;
1521
1522         buf = "";
1523         if (size)
1524                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1525         close(fd);
1526         if (buf == MAP_FAILED)
1527                 return -1;
1528
1529         if (!type)
1530                 type = "blob";
1531         if (write_object)
1532                 ret = write_sha1_file(buf, size, type, sha1);
1533         else {
1534                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1535                 ret = 0;
1536         }
1537         if (size)
1538                 munmap(buf, size);
1539         return ret;
1540 }
1541
1542 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1543 {
1544         int fd;
1545         char *target;
1546
1547         switch (st->st_mode & S_IFMT) {
1548         case S_IFREG:
1549                 fd = open(path, O_RDONLY);
1550                 if (fd < 0)
1551                         return error("open(\"%s\"): %s", path,
1552                                      strerror(errno));
1553                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1554                         return error("%s: failed to insert into database",
1555                                      path);
1556                 break;
1557         case S_IFLNK:
1558                 target = xmalloc(st->st_size+1);
1559                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1560                         char *errstr = strerror(errno);
1561                         free(target);
1562                         return error("readlink(\"%s\"): %s", path,
1563                                      errstr);
1564                 }
1565                 if (!write_object) {
1566                         unsigned char hdr[50];
1567                         int hdrlen;
1568                         write_sha1_file_prepare(target, st->st_size, "blob",
1569                                                 sha1, hdr, &hdrlen);
1570                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1571                         return error("%s: failed to insert into database",
1572                                      path);
1573                 free(target);
1574                 break;
1575         default:
1576                 return error("%s: unsupported file type", path);
1577         }
1578         return 0;
1579 }