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 similar to that environment variable but can be
 188  * LF separated.  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         const char *objdir = get_object_directory();
 201         int base_len = -1;
 202
 203         last = alt;
 204         while (last < ep) {
 205                 cp = last;
 206                 if (cp < ep && *cp == '#') {
 207                         while (cp < ep && *cp != sep)
 208                                 cp++;
 209                         last = cp + 1;
 210                         continue;
 211                 }
 212                 for ( ; cp < ep && *cp != sep; cp++)
 213                         ;
 214                 if (last != cp) {
 215                         struct alternate_object_database *alt;
 216                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 217                         int pfxlen = cp - last;
 218                         int entlen = pfxlen + 43;
 219
 220                         if (*last != '/' && relative_base) {
 221                                 /* Relative alt-odb */
 222                                 if (base_len < 0)
 223                                         base_len = strlen(relative_base) + 1;
 224                                 entlen += base_len;
 225                                 pfxlen += base_len;
 226                         }
 227                         ent = xmalloc(sizeof(*ent) + entlen);
 228
 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                         /* Prevent the common mistake of listing the same
 242                          * thing twice, or object directory itself.
 243                          */
 244                         for (alt = alt_odb_list; alt; alt = alt->next)
 245                                 if (!memcmp(ent->base, alt->base, pfxlen))
 246                                         goto bad;
 247                         if (!memcmp(ent->base, objdir, pfxlen)) {
 248                         bad:
 249                                 free(ent);
 250                         }
 251                         else {
 252                                 *alt_odb_tail = ent;
 253                                 alt_odb_tail = &(ent->next);
 254                                 ent->next = NULL;
 255                         }
 256                 }
 257                 while (cp < ep && *cp == sep)
 258                         cp++;
 259                 last = cp;
 260         }
 261 }
 262
 263 void prepare_alt_odb(void)
 264 {
 265         char path[PATH_MAX];
 266         char *map;
 267         int fd;
 268         struct stat st;
 269         char *alt;
 270
 271         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 272         if (!alt) alt = "";
 273
 274         if (alt_odb_tail)
 275                 return;
 276         alt_odb_tail = &alt_odb_list;
 277         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 278
 279         sprintf(path, "%s/info/alternates", get_object_directory());
 280         fd = open(path, O_RDONLY);
 281         if (fd < 0)
 282                 return;
 283         if (fstat(fd, &st) || (st.st_size == 0)) {
 284                 close(fd);
 285                 return;
 286         }
 287         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 288         close(fd);
 289         if (map == MAP_FAILED)
 290                 return;
 291
 292         link_alt_odb_entries(map, map + st.st_size, '\n',
 293                              get_object_directory());
 294         munmap(map, st.st_size);
 295 }
 296
 297 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 298 {
 299         char *name = sha1_file_name(sha1);
 300         struct alternate_object_database *alt;
 301
 302         if (!stat(name, st))
 303                 return name;
 304         prepare_alt_odb();
 305         for (alt = alt_odb_list; alt; alt = alt->next) {
 306                 name = alt->name;
 307                 fill_sha1_path(name, sha1);
 308                 if (!stat(alt->base, st))
 309                         return alt->base;
 310         }
 311         return NULL;
 312 }
 313
 314 #define PACK_MAX_SZ (1<<26)
 315 static int pack_used_ctr;
 316 static unsigned long pack_mapped;
 317 struct packed_git *packed_git;
 318
 319 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 320                                 void **idx_map_)
 321 {
 322         void *idx_map;
 323         unsigned int *index;
 324         unsigned long idx_size;
 325         int nr, i;
 326         int fd = open(path, O_RDONLY);
 327         struct stat st;
 328         if (fd < 0)
 329                 return -1;
 330         if (fstat(fd, &st)) {
 331                 close(fd);
 332                 return -1;
 333         }
 334         idx_size = st.st_size;
 335         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 336         close(fd);
 337         if (idx_map == MAP_FAILED)
 338                 return -1;
 339
 340         index = idx_map;
 341         *idx_map_ = idx_map;
 342         *idx_size_ = idx_size;
 343
 344         /* check index map */
 345         if (idx_size < 4*256 + 20 + 20)
 346                 return error("index file too small");
 347         nr = 0;
 348         for (i = 0; i < 256; i++) {
 349                 unsigned int n = ntohl(index[i]);
 350                 if (n < nr)
 351                         return error("non-monotonic index");
 352                 nr = n;
 353         }
 354
 355         /*
 356          * Total size:
 357          *  - 256 index entries 4 bytes each
 358          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 359          *  - 20-byte SHA1 of the packfile
 360          *  - 20-byte SHA1 file checksum
 361          */
 362         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 363                 return error("wrong index file size");
 364
 365         return 0;
 366 }
 367
 368 static int unuse_one_packed_git(void)
 369 {
 370         struct packed_git *p, *lru = NULL;
 371
 372         for (p = packed_git; p; p = p->next) {
 373                 if (p->pack_use_cnt || !p->pack_base)
 374                         continue;
 375                 if (!lru || p->pack_last_used < lru->pack_last_used)
 376                         lru = p;
 377         }
 378         if (!lru)
 379                 return 0;
 380         munmap(lru->pack_base, lru->pack_size);
 381         lru->pack_base = NULL;
 382         return 1;
 383 }
 384
 385 void unuse_packed_git(struct packed_git *p)
 386 {
 387         p->pack_use_cnt--;
 388 }
 389
 390 int use_packed_git(struct packed_git *p)
 391 {
 392         if (!p->pack_size) {
 393                 struct stat st;
 394                 // We created the struct before we had the pack
 395                 stat(p->pack_name, &st);
 396                 if (!S_ISREG(st.st_mode))
 397                         die("packfile %s not a regular file", p->pack_name);
 398                 p->pack_size = st.st_size;
 399         }
 400         if (!p->pack_base) {
 401                 int fd;
 402                 struct stat st;
 403                 void *map;
 404
 405                 pack_mapped += p->pack_size;
 406                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 407                         ; /* nothing */
 408                 fd = open(p->pack_name, O_RDONLY);
 409                 if (fd < 0)
 410                         die("packfile %s cannot be opened", p->pack_name);
 411                 if (fstat(fd, &st)) {
 412                         close(fd);
 413                         die("packfile %s cannot be opened", p->pack_name);
 414                 }
 415                 if (st.st_size != p->pack_size)
 416                         die("packfile %s size mismatch.", p->pack_name);
 417                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 418                 close(fd);
 419                 if (map == MAP_FAILED)
 420                         die("packfile %s cannot be mapped.", p->pack_name);
 421                 p->pack_base = map;
 422
 423                 /* Check if the pack file matches with the index file.
 424                  * this is cheap.
 425                  */
 426                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 427                            p->pack_base + p->pack_size - 20, 20)) {
 428
 429                         die("packfile %s does not match index.", p->pack_name);
 430                 }
 431         }
 432         p->pack_last_used = pack_used_ctr++;
 433         p->pack_use_cnt++;
 434         return 0;
 435 }
 436
 437 struct packed_git *add_packed_git(char *path, int path_len, int local)
 438 {
 439         struct stat st;
 440         struct packed_git *p;
 441         unsigned long idx_size;
 442         void *idx_map;
 443         unsigned char sha1[20];
 444
 445         if (check_packed_git_idx(path, &idx_size, &idx_map))
 446                 return NULL;
 447
 448         /* do we have a corresponding .pack file? */
 449         strcpy(path + path_len - 4, ".pack");
 450         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 451                 munmap(idx_map, idx_size);
 452                 return NULL;
 453         }
 454         /* ok, it looks sane as far as we can check without
 455          * actually mapping the pack file.
 456          */
 457         p = xmalloc(sizeof(*p) + path_len + 2);
 458         strcpy(p->pack_name, path);
 459         p->index_size = idx_size;
 460         p->pack_size = st.st_size;
 461         p->index_base = idx_map;
 462         p->next = NULL;
 463         p->pack_base = NULL;
 464         p->pack_last_used = 0;
 465         p->pack_use_cnt = 0;
 466         p->pack_local = local;
 467         if (!get_sha1_hex(path + path_len - 40 - 4, sha1))
 468                 memcpy(p->sha1, sha1, 20);
 469         return p;
 470 }
 471
 472 struct packed_git *parse_pack_index(unsigned char *sha1)
 473 {
 474         char *path = sha1_pack_index_name(sha1);
 475         return parse_pack_index_file(sha1, path);
 476 }
 477
 478 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 479 {
 480         struct packed_git *p;
 481         unsigned long idx_size;
 482         void *idx_map;
 483         char *path;
 484
 485         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 486                 return NULL;
 487
 488         path = sha1_pack_name(sha1);
 489
 490         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 491         strcpy(p->pack_name, path);
 492         p->index_size = idx_size;
 493         p->pack_size = 0;
 494         p->index_base = idx_map;
 495         p->next = NULL;
 496         p->pack_base = NULL;
 497         p->pack_last_used = 0;
 498         p->pack_use_cnt = 0;
 499         memcpy(p->sha1, sha1, 20);
 500         return p;
 501 }
 502
 503 void install_packed_git(struct packed_git *pack)
 504 {
 505         pack->next = packed_git;
 506         packed_git = pack;
 507 }
 508
 509 static void prepare_packed_git_one(char *objdir, int local)
 510 {
 511         char path[PATH_MAX];
 512         int len;
 513         DIR *dir;
 514         struct dirent *de;
 515
 516         sprintf(path, "%s/pack", objdir);
 517         len = strlen(path);
 518         dir = opendir(path);
 519         if (!dir)
 520                 return;
 521         path[len++] = '/';
 522         while ((de = readdir(dir)) != NULL) {
 523                 int namelen = strlen(de->d_name);
 524                 struct packed_git *p;
 525
 526                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 527                         continue;
 528
 529                 /* we have .idx.  Is it a file we can map? */
 530                 strcpy(path + len, de->d_name);
 531                 p = add_packed_git(path, len + namelen, local);
 532                 if (!p)
 533                         continue;
 534                 p->next = packed_git;
 535                 packed_git = p;
 536         }
 537         closedir(dir);
 538 }
 539
 540 void prepare_packed_git(void)
 541 {
 542         static int run_once = 0;
 543         struct alternate_object_database *alt;
 544
 545         if (run_once)
 546                 return;
 547         prepare_packed_git_one(get_object_directory(), 1);
 548         prepare_alt_odb();
 549         for (alt = alt_odb_list; alt; alt = alt->next) {
 550                 alt->name[-1] = 0;
 551                 prepare_packed_git_one(alt->base, 0);
 552                 alt->name[-1] = '/';
 553         }
 554         run_once = 1;
 555 }
 556
 557 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 558 {
 559         char header[100];
 560         unsigned char real_sha1[20];
 561         SHA_CTX c;
 562
 563         SHA1_Init(&c);
 564         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 565         SHA1_Update(&c, map, size);
 566         SHA1_Final(real_sha1, &c);
 567         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 568 }
 569
 570 static void *map_sha1_file_internal(const unsigned char *sha1,
 571                                     unsigned long *size)
 572 {
 573         struct stat st;
 574         void *map;
 575         int fd;
 576         char *filename = find_sha1_file(sha1, &st);
 577
 578         if (!filename) {
 579                 return NULL;
 580         }
 581
 582         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 583         if (fd < 0) {
 584                 /* See if it works without O_NOATIME */
 585                 switch (sha1_file_open_flag) {
 586                 default:
 587                         fd = open(filename, O_RDONLY);
 588                         if (fd >= 0)
 589                                 break;
 590                 /* Fallthrough */
 591                 case 0:
 592                         return NULL;
 593                 }
 594
 595                 /* If it failed once, it will probably fail again.
 596                  * Stop using O_NOATIME
 597                  */
 598                 sha1_file_open_flag = 0;
 599         }
 600         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 601         close(fd);
 602         if (map == MAP_FAILED)
 603                 return NULL;
 604         *size = st.st_size;
 605         return map;
 606 }
 607
 608 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 609 {
 610         /* Get the data stream */
 611         memset(stream, 0, sizeof(*stream));
 612         stream->next_in = map;
 613         stream->avail_in = mapsize;
 614         stream->next_out = buffer;
 615         stream->avail_out = size;
 616
 617         inflateInit(stream);
 618         return inflate(stream, 0);
 619 }
 620
 621 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 622 {
 623         int bytes = strlen(buffer) + 1;
 624         unsigned char *buf = xmalloc(1+size);
 625
 626         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 627         bytes = stream->total_out - bytes;
 628         if (bytes < size) {
 629                 stream->next_out = buf + bytes;
 630                 stream->avail_out = size - bytes;
 631                 while (inflate(stream, Z_FINISH) == Z_OK)
 632                         /* nothing */;
 633         }
 634         buf[size] = 0;
 635         inflateEnd(stream);
 636         return buf;
 637 }
 638
 639 /*
 640  * We used to just use "sscanf()", but that's actually way
 641  * too permissive for what we want to check. So do an anal
 642  * object header parse by hand.
 643  */
 644 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 645 {
 646         int i;
 647         unsigned long size;
 648
 649         /*
 650          * The type can be at most ten bytes (including the
 651          * terminating '\0' that we add), and is followed by
 652          * a space.
 653          */
 654         i = 10;
 655         for (;;) {
 656                 char c = *hdr++;
 657                 if (c == ' ')
 658                         break;
 659                 if (!--i)
 660                         return -1;
 661                 *type++ = c;
 662         }
 663         *type = 0;
 664
 665         /*
 666          * The length must follow immediately, and be in canonical
 667          * decimal format (ie "010" is not valid).
 668          */
 669         size = *hdr++ - '0';
 670         if (size > 9)
 671                 return -1;
 672         if (size) {
 673                 for (;;) {
 674                         unsigned long c = *hdr - '0';
 675                         if (c > 9)
 676                                 break;
 677                         hdr++;
 678                         size = size * 10 + c;
 679                 }
 680         }
 681         *sizep = size;
 682
 683         /*
 684          * The length must be followed by a zero byte
 685          */
 686         return *hdr ? -1 : 0;
 687 }
 688
 689 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 690 {
 691         int ret;
 692         z_stream stream;
 693         char hdr[8192];
 694
 695         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 696         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 697                 return NULL;
 698
 699         return unpack_sha1_rest(&stream, hdr, *size);
 700 }
 701
 702 /* forward declaration for a mutually recursive function */
 703 static int packed_object_info(struct pack_entry *entry,
 704                               char *type, unsigned long *sizep);
 705
 706 static int packed_delta_info(unsigned char *base_sha1,
 707                              unsigned long delta_size,
 708                              unsigned long left,
 709                              char *type,
 710                              unsigned long *sizep,
 711                              struct packed_git *p)
 712 {
 713         struct pack_entry base_ent;
 714
 715         if (left < 20)
 716                 die("truncated pack file");
 717
 718         /* The base entry _must_ be in the same pack */
 719         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 720                 die("failed to find delta-pack base object %s",
 721                     sha1_to_hex(base_sha1));
 722
 723         /* We choose to only get the type of the base object and
 724          * ignore potentially corrupt pack file that expects the delta
 725          * based on a base with a wrong size.  This saves tons of
 726          * inflate() calls.
 727          */
 728
 729         if (packed_object_info(&base_ent, type, NULL))
 730                 die("cannot get info for delta-pack base");
 731
 732         if (sizep) {
 733                 const unsigned char *data;
 734                 unsigned char delta_head[64];
 735                 unsigned long result_size;
 736                 z_stream stream;
 737                 int st;
 738
 739                 memset(&stream, 0, sizeof(stream));
 740
 741                 data = stream.next_in = base_sha1 + 20;
 742                 stream.avail_in = left - 20;
 743                 stream.next_out = delta_head;
 744                 stream.avail_out = sizeof(delta_head);
 745
 746                 inflateInit(&stream);
 747                 st = inflate(&stream, Z_FINISH);
 748                 inflateEnd(&stream);
 749                 if ((st != Z_STREAM_END) &&
 750                     stream.total_out != sizeof(delta_head))
 751                         die("delta data unpack-initial failed");
 752
 753                 /* Examine the initial part of the delta to figure out
 754                  * the result size.
 755                  */
 756                 data = delta_head;
 757                 get_delta_hdr_size(&data); /* ignore base size */
 758
 759                 /* Read the result size */
 760                 result_size = get_delta_hdr_size(&data);
 761                 *sizep = result_size;
 762         }
 763         return 0;
 764 }
 765
 766 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 767         enum object_type *type, unsigned long *sizep)
 768 {
 769         unsigned shift;
 770         unsigned char *pack, c;
 771         unsigned long size;
 772
 773         if (offset >= p->pack_size)
 774                 die("object offset outside of pack file");
 775
 776         pack =  p->pack_base + offset;
 777         c = *pack++;
 778         offset++;
 779         *type = (c >> 4) & 7;
 780         size = c & 15;
 781         shift = 4;
 782         while (c & 0x80) {
 783                 if (offset >= p->pack_size)
 784                         die("object offset outside of pack file");
 785                 c = *pack++;
 786                 offset++;
 787                 size += (c & 0x7f) << shift;
 788                 shift += 7;
 789         }
 790         *sizep = size;
 791         return offset;
 792 }
 793
 794 void packed_object_info_detail(struct pack_entry *e,
 795                                char *type,
 796                                unsigned long *size,
 797                                unsigned long *store_size,
 798                                int *delta_chain_length,
 799                                unsigned char *base_sha1)
 800 {
 801         struct packed_git *p = e->p;
 802         unsigned long offset, left;
 803         unsigned char *pack;
 804         enum object_type kind;
 805
 806         offset = unpack_object_header(p, e->offset, &kind, size);
 807         pack = p->pack_base + offset;
 808         left = p->pack_size - offset;
 809         if (kind != OBJ_DELTA)
 810                 *delta_chain_length = 0;
 811         else {
 812                 int chain_length = 0;
 813                 memcpy(base_sha1, pack, 20);
 814                 do {
 815                         struct pack_entry base_ent;
 816                         unsigned long junk;
 817
 818                         find_pack_entry_one(pack, &base_ent, p);
 819                         offset = unpack_object_header(p, base_ent.offset,
 820                                                       &kind, &junk);
 821                         pack = p->pack_base + offset;
 822                         chain_length++;
 823                 } while (kind == OBJ_DELTA);
 824                 *delta_chain_length = chain_length;
 825         }
 826         switch (kind) {
 827         case OBJ_COMMIT:
 828                 strcpy(type, "commit");
 829                 break;
 830         case OBJ_TREE:
 831                 strcpy(type, "tree");
 832                 break;
 833         case OBJ_BLOB:
 834                 strcpy(type, "blob");
 835                 break;
 836         case OBJ_TAG:
 837                 strcpy(type, "tag");
 838                 break;
 839         default:
 840                 die("corrupted pack file %s containing object of kind %d",
 841                     p->pack_name, kind);
 842         }
 843         *store_size = 0; /* notyet */
 844 }
 845
 846 static int packed_object_info(struct pack_entry *entry,
 847                               char *type, unsigned long *sizep)
 848 {
 849         struct packed_git *p = entry->p;
 850         unsigned long offset, size, left;
 851         unsigned char *pack;
 852         enum object_type kind;
 853         int retval;
 854
 855         if (use_packed_git(p))
 856                 die("cannot map packed file");
 857
 858         offset = unpack_object_header(p, entry->offset, &kind, &size);
 859         pack = p->pack_base + offset;
 860         left = p->pack_size - offset;
 861
 862         switch (kind) {
 863         case OBJ_DELTA:
 864                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 865                 unuse_packed_git(p);
 866                 return retval;
 867         case OBJ_COMMIT:
 868                 strcpy(type, "commit");
 869                 break;
 870         case OBJ_TREE:
 871                 strcpy(type, "tree");
 872                 break;
 873         case OBJ_BLOB:
 874                 strcpy(type, "blob");
 875                 break;
 876         case OBJ_TAG:
 877                 strcpy(type, "tag");
 878                 break;
 879         default:
 880                 die("corrupted pack file %s containing object of kind %d",
 881                     p->pack_name, kind);
 882         }
 883         if (sizep)
 884                 *sizep = size;
 885         unuse_packed_git(p);
 886         return 0;
 887 }
 888
 889 /* forward declaration for a mutually recursive function */
 890 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 891
 892 static void *unpack_delta_entry(unsigned char *base_sha1,
 893                                 unsigned long delta_size,
 894                                 unsigned long left,
 895                                 char *type,
 896                                 unsigned long *sizep,
 897                                 struct packed_git *p)
 898 {
 899         struct pack_entry base_ent;
 900         void *data, *delta_data, *result, *base;
 901         unsigned long data_size, result_size, base_size;
 902         z_stream stream;
 903         int st;
 904
 905         if (left < 20)
 906                 die("truncated pack file");
 907         data = base_sha1 + 20;
 908         data_size = left - 20;
 909         delta_data = xmalloc(delta_size);
 910
 911         memset(&stream, 0, sizeof(stream));
 912
 913         stream.next_in = data;
 914         stream.avail_in = data_size;
 915         stream.next_out = delta_data;
 916         stream.avail_out = delta_size;
 917
 918         inflateInit(&stream);
 919         st = inflate(&stream, Z_FINISH);
 920         inflateEnd(&stream);
 921         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 922                 die("delta data unpack failed");
 923
 924         /* The base entry _must_ be in the same pack */
 925         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 926                 die("failed to find delta-pack base object %s",
 927                     sha1_to_hex(base_sha1));
 928         base = unpack_entry_gently(&base_ent, type, &base_size);
 929         if (!base)
 930                 die("failed to read delta-pack base object %s",
 931                     sha1_to_hex(base_sha1));
 932         result = patch_delta(base, base_size,
 933                              delta_data, delta_size,
 934                              &result_size);
 935         if (!result)
 936                 die("failed to apply delta");
 937         free(delta_data);
 938         free(base);
 939         *sizep = result_size;
 940         return result;
 941 }
 942
 943 static void *unpack_non_delta_entry(unsigned char *data,
 944                                     unsigned long size,
 945                                     unsigned long left)
 946 {
 947         int st;
 948         z_stream stream;
 949         unsigned char *buffer;
 950
 951         buffer = xmalloc(size + 1);
 952         buffer[size] = 0;
 953         memset(&stream, 0, sizeof(stream));
 954         stream.next_in = data;
 955         stream.avail_in = left;
 956         stream.next_out = buffer;
 957         stream.avail_out = size;
 958
 959         inflateInit(&stream);
 960         st = inflate(&stream, Z_FINISH);
 961         inflateEnd(&stream);
 962         if ((st != Z_STREAM_END) || stream.total_out != size) {
 963                 free(buffer);
 964                 return NULL;
 965         }
 966
 967         return buffer;
 968 }
 969
 970 static void *unpack_entry(struct pack_entry *entry,
 971                           char *type, unsigned long *sizep)
 972 {
 973         struct packed_git *p = entry->p;
 974         void *retval;
 975
 976         if (use_packed_git(p))
 977                 die("cannot map packed file");
 978         retval = unpack_entry_gently(entry, type, sizep);
 979         unuse_packed_git(p);
 980         if (!retval)
 981                 die("corrupted pack file %s", p->pack_name);
 982         return retval;
 983 }
 984
 985 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
 986 void *unpack_entry_gently(struct pack_entry *entry,
 987                           char *type, unsigned long *sizep)
 988 {
 989         struct packed_git *p = entry->p;
 990         unsigned long offset, size, left;
 991         unsigned char *pack;
 992         enum object_type kind;
 993         void *retval;
 994
 995         offset = unpack_object_header(p, entry->offset, &kind, &size);
 996         pack = p->pack_base + offset;
 997         left = p->pack_size - offset;
 998         switch (kind) {
 999         case OBJ_DELTA:
1000                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1001                 return retval;
1002         case OBJ_COMMIT:
1003                 strcpy(type, "commit");
1004                 break;
1005         case OBJ_TREE:
1006                 strcpy(type, "tree");
1007                 break;
1008         case OBJ_BLOB:
1009                 strcpy(type, "blob");
1010                 break;
1011         case OBJ_TAG:
1012                 strcpy(type, "tag");
1013                 break;
1014         default:
1015                 return NULL;
1016         }
1017         *sizep = size;
1018         retval = unpack_non_delta_entry(pack, size, left);
1019         return retval;
1020 }
1021
1022 int num_packed_objects(const struct packed_git *p)
1023 {
1024         /* See check_packed_git_idx() */
1025         return (p->index_size - 20 - 20 - 4*256) / 24;
1026 }
1027
1028 int nth_packed_object_sha1(const struct packed_git *p, int n,
1029                            unsigned char* sha1)
1030 {
1031         void *index = p->index_base + 256;
1032         if (n < 0 || num_packed_objects(p) <= n)
1033                 return -1;
1034         memcpy(sha1, (index + 24 * n + 4), 20);
1035         return 0;
1036 }
1037
1038 int find_pack_entry_one(const unsigned char *sha1,
1039                         struct pack_entry *e, struct packed_git *p)
1040 {
1041         unsigned int *level1_ofs = p->index_base;
1042         int hi = ntohl(level1_ofs[*sha1]);
1043         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1044         void *index = p->index_base + 256;
1045
1046         do {
1047                 int mi = (lo + hi) / 2;
1048                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1049                 if (!cmp) {
1050                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1051                         memcpy(e->sha1, sha1, 20);
1052                         e->p = p;
1053                         return 1;
1054                 }
1055                 if (cmp > 0)
1056                         hi = mi;
1057                 else
1058                         lo = mi+1;
1059         } while (lo < hi);
1060         return 0;
1061 }
1062
1063 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1064 {
1065         struct packed_git *p;
1066         prepare_packed_git();
1067
1068         for (p = packed_git; p; p = p->next) {
1069                 if (find_pack_entry_one(sha1, e, p))
1070                         return 1;
1071         }
1072         return 0;
1073 }
1074
1075 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1076                                   struct packed_git *packs)
1077 {
1078         struct packed_git *p;
1079         struct pack_entry e;
1080
1081         for (p = packs; p; p = p->next) {
1082                 if (find_pack_entry_one(sha1, &e, p))
1083                         return p;
1084         }
1085         return NULL;
1086
1087 }
1088
1089 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1090 {
1091         int status;
1092         unsigned long mapsize, size;
1093         void *map;
1094         z_stream stream;
1095         char hdr[128];
1096
1097         map = map_sha1_file_internal(sha1, &mapsize);
1098         if (!map) {
1099                 struct pack_entry e;
1100
1101                 if (!find_pack_entry(sha1, &e))
1102                         return error("unable to find %s", sha1_to_hex(sha1));
1103                 return packed_object_info(&e, type, sizep);
1104         }
1105         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1106                 status = error("unable to unpack %s header",
1107                                sha1_to_hex(sha1));
1108         if (parse_sha1_header(hdr, type, &size) < 0)
1109                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1110         else {
1111                 status = 0;
1112                 if (sizep)
1113                         *sizep = size;
1114         }
1115         inflateEnd(&stream);
1116         munmap(map, mapsize);
1117         return status;
1118 }
1119
1120 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1121 {
1122         struct pack_entry e;
1123
1124         if (!find_pack_entry(sha1, &e)) {
1125                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1126                 return NULL;
1127         }
1128         return unpack_entry(&e, type, size);
1129 }
1130
1131 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1132 {
1133         unsigned long mapsize;
1134         void *map, *buf;
1135         struct pack_entry e;
1136
1137         if (find_pack_entry(sha1, &e))
1138                 return read_packed_sha1(sha1, type, size);
1139         map = map_sha1_file_internal(sha1, &mapsize);
1140         if (map) {
1141                 buf = unpack_sha1_file(map, mapsize, type, size);
1142                 munmap(map, mapsize);
1143                 return buf;
1144         }
1145         return NULL;
1146 }
1147
1148 void *read_object_with_reference(const unsigned char *sha1,
1149                                  const char *required_type,
1150                                  unsigned long *size,
1151                                  unsigned char *actual_sha1_return)
1152 {
1153         char type[20];
1154         void *buffer;
1155         unsigned long isize;
1156         unsigned char actual_sha1[20];
1157
1158         memcpy(actual_sha1, sha1, 20);
1159         while (1) {
1160                 int ref_length = -1;
1161                 const char *ref_type = NULL;
1162
1163                 buffer = read_sha1_file(actual_sha1, type, &isize);
1164                 if (!buffer)
1165                         return NULL;
1166                 if (!strcmp(type, required_type)) {
1167                         *size = isize;
1168                         if (actual_sha1_return)
1169                                 memcpy(actual_sha1_return, actual_sha1, 20);
1170                         return buffer;
1171                 }
1172                 /* Handle references */
1173                 else if (!strcmp(type, "commit"))
1174                         ref_type = "tree ";
1175                 else if (!strcmp(type, "tag"))
1176                         ref_type = "object ";
1177                 else {
1178                         free(buffer);
1179                         return NULL;
1180                 }
1181                 ref_length = strlen(ref_type);
1182
1183                 if (memcmp(buffer, ref_type, ref_length) ||
1184                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1185                         free(buffer);
1186                         return NULL;
1187                 }
1188                 free(buffer);
1189                 /* Now we have the ID of the referred-to object in
1190                  * actual_sha1.  Check again. */
1191         }
1192 }
1193
1194 char *write_sha1_file_prepare(void *buf,
1195                               unsigned long len,
1196                               const char *type,
1197                               unsigned char *sha1,
1198                               unsigned char *hdr,
1199                               int *hdrlen)
1200 {
1201         SHA_CTX c;
1202
1203         /* Generate the header */
1204         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1205
1206         /* Sha1.. */
1207         SHA1_Init(&c);
1208         SHA1_Update(&c, hdr, *hdrlen);
1209         SHA1_Update(&c, buf, len);
1210         SHA1_Final(sha1, &c);
1211
1212         return sha1_file_name(sha1);
1213 }
1214
1215 /*
1216  * Link the tempfile to the final place, possibly creating the
1217  * last directory level as you do so.
1218  *
1219  * Returns the errno on failure, 0 on success.
1220  */
1221 static int link_temp_to_file(const char *tmpfile, char *filename)
1222 {
1223         int ret;
1224
1225         if (!link(tmpfile, filename))
1226                 return 0;
1227
1228         /*
1229          * Try to mkdir the last path component if that failed
1230          * with an ENOENT.
1231          *
1232          * Re-try the "link()" regardless of whether the mkdir
1233          * succeeds, since a race might mean that somebody
1234          * else succeeded.
1235          */
1236         ret = errno;
1237         if (ret == ENOENT) {
1238                 char *dir = strrchr(filename, '/');
1239                 if (dir) {
1240                         *dir = 0;
1241                         mkdir(filename, 0777);
1242                         *dir = '/';
1243                         if (!link(tmpfile, filename))
1244                                 return 0;
1245                         ret = errno;
1246                 }
1247         }
1248         return ret;
1249 }
1250
1251 /*
1252  * Move the just written object into its final resting place
1253  */
1254 int move_temp_to_file(const char *tmpfile, char *filename)
1255 {
1256         int ret = link_temp_to_file(tmpfile, filename);
1257
1258         /*
1259          * Coda hack - coda doesn't like cross-directory links,
1260          * so we fall back to a rename, which will mean that it
1261          * won't be able to check collisions, but that's not a
1262          * big deal.
1263          *
1264          * The same holds for FAT formatted media.
1265          *
1266          * When this succeeds, we just return 0. We have nothing
1267          * left to unlink.
1268          */
1269         if (ret && ret != EEXIST) {
1270                 if (!rename(tmpfile, filename))
1271                         return 0;
1272                 ret = errno;
1273         }
1274         unlink(tmpfile);
1275         if (ret) {
1276                 if (ret != EEXIST) {
1277                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1278                         return -1;
1279                 }
1280                 /* FIXME!!! Collision check here ? */
1281         }
1282
1283         return 0;
1284 }
1285
1286 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1287 {
1288         int size;
1289         unsigned char *compressed;
1290         z_stream stream;
1291         unsigned char sha1[20];
1292         char *filename;
1293         static char tmpfile[PATH_MAX];
1294         unsigned char hdr[50];
1295         int fd, hdrlen;
1296
1297         /* Normally if we have it in the pack then we do not bother writing
1298          * it out into .git/objects/??/?{38} file.
1299          */
1300         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1301         if (returnsha1)
1302                 memcpy(returnsha1, sha1, 20);
1303         if (has_sha1_file(sha1))
1304                 return 0;
1305         fd = open(filename, O_RDONLY);
1306         if (fd >= 0) {
1307                 /*
1308                  * FIXME!!! We might do collision checking here, but we'd
1309                  * need to uncompress the old file and check it. Later.
1310                  */
1311                 close(fd);
1312                 return 0;
1313         }
1314
1315         if (errno != ENOENT) {
1316                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1317                 return -1;
1318         }
1319
1320         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1321
1322         fd = mkstemp(tmpfile);
1323         if (fd < 0) {
1324                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1325                 return -1;
1326         }
1327
1328         /* Set it up */
1329         memset(&stream, 0, sizeof(stream));
1330         deflateInit(&stream, Z_BEST_COMPRESSION);
1331         size = deflateBound(&stream, len+hdrlen);
1332         compressed = xmalloc(size);
1333
1334         /* Compress it */
1335         stream.next_out = compressed;
1336         stream.avail_out = size;
1337
1338         /* First header.. */
1339         stream.next_in = hdr;
1340         stream.avail_in = hdrlen;
1341         while (deflate(&stream, 0) == Z_OK)
1342                 /* nothing */;
1343
1344         /* Then the data itself.. */
1345         stream.next_in = buf;
1346         stream.avail_in = len;
1347         while (deflate(&stream, Z_FINISH) == Z_OK)
1348                 /* nothing */;
1349         deflateEnd(&stream);
1350         size = stream.total_out;
1351
1352         if (write(fd, compressed, size) != size)
1353                 die("unable to write file");
1354         fchmod(fd, 0444);
1355         close(fd);
1356         free(compressed);
1357
1358         return move_temp_to_file(tmpfile, filename);
1359 }
1360
1361 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1362 {
1363         ssize_t size;
1364         unsigned long objsize;
1365         int posn = 0;
1366         void *map = map_sha1_file_internal(sha1, &objsize);
1367         void *buf = map;
1368         void *temp_obj = NULL;
1369         z_stream stream;
1370
1371         if (!buf) {
1372                 unsigned char *unpacked;
1373                 unsigned long len;
1374                 char type[20];
1375                 char hdr[50];
1376                 int hdrlen;
1377                 // need to unpack and recompress it by itself
1378                 unpacked = read_packed_sha1(sha1, type, &len);
1379
1380                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1381
1382                 /* Set it up */
1383                 memset(&stream, 0, sizeof(stream));
1384                 deflateInit(&stream, Z_BEST_COMPRESSION);
1385                 size = deflateBound(&stream, len + hdrlen);
1386                 temp_obj = buf = xmalloc(size);
1387
1388                 /* Compress it */
1389                 stream.next_out = buf;
1390                 stream.avail_out = size;
1391
1392                 /* First header.. */
1393                 stream.next_in = (void *)hdr;
1394                 stream.avail_in = hdrlen;
1395                 while (deflate(&stream, 0) == Z_OK)
1396                         /* nothing */;
1397
1398                 /* Then the data itself.. */
1399                 stream.next_in = unpacked;
1400                 stream.avail_in = len;
1401                 while (deflate(&stream, Z_FINISH) == Z_OK)
1402                         /* nothing */;
1403                 deflateEnd(&stream);
1404                 free(unpacked);
1405
1406                 objsize = stream.total_out;
1407         }
1408
1409         do {
1410                 size = write(fd, buf + posn, objsize - posn);
1411                 if (size <= 0) {
1412                         if (!size) {
1413                                 fprintf(stderr, "write closed");
1414                         } else {
1415                                 perror("write ");
1416                         }
1417                         return -1;
1418                 }
1419                 posn += size;
1420         } while (posn < objsize);
1421
1422         if (map)
1423                 munmap(map, objsize);
1424         if (temp_obj)
1425                 free(temp_obj);
1426
1427         return 0;
1428 }
1429
1430 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1431                        size_t bufsize, size_t *bufposn)
1432 {
1433         char tmpfile[PATH_MAX];
1434         int local;
1435         z_stream stream;
1436         unsigned char real_sha1[20];
1437         unsigned char discard[4096];
1438         int ret;
1439         SHA_CTX c;
1440
1441         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1442
1443         local = mkstemp(tmpfile);
1444         if (local < 0)
1445                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1446
1447         memset(&stream, 0, sizeof(stream));
1448
1449         inflateInit(&stream);
1450
1451         SHA1_Init(&c);
1452
1453         do {
1454                 ssize_t size;
1455                 if (*bufposn) {
1456                         stream.avail_in = *bufposn;
1457                         stream.next_in = (unsigned char *) buffer;
1458                         do {
1459                                 stream.next_out = discard;
1460                                 stream.avail_out = sizeof(discard);
1461                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1462                                 SHA1_Update(&c, discard, sizeof(discard) -
1463                                             stream.avail_out);
1464                         } while (stream.avail_in && ret == Z_OK);
1465                         write(local, buffer, *bufposn - stream.avail_in);
1466                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1467                                 stream.avail_in);
1468                         *bufposn = stream.avail_in;
1469                         if (ret != Z_OK)
1470                                 break;
1471                 }
1472                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1473                 if (size <= 0) {
1474                         close(local);
1475                         unlink(tmpfile);
1476                         if (!size)
1477                                 return error("Connection closed?");
1478                         perror("Reading from connection");
1479                         return -1;
1480                 }
1481                 *bufposn += size;
1482         } while (1);
1483         inflateEnd(&stream);
1484
1485         close(local);
1486         SHA1_Final(real_sha1, &c);
1487         if (ret != Z_STREAM_END) {
1488                 unlink(tmpfile);
1489                 return error("File %s corrupted", sha1_to_hex(sha1));
1490         }
1491         if (memcmp(sha1, real_sha1, 20)) {
1492                 unlink(tmpfile);
1493                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1494         }
1495
1496         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1497 }
1498
1499 int has_pack_index(const unsigned char *sha1)
1500 {
1501         struct stat st;
1502         if (stat(sha1_pack_index_name(sha1), &st))
1503                 return 0;
1504         return 1;
1505 }
1506
1507 int has_pack_file(const unsigned char *sha1)
1508 {
1509         struct stat st;
1510         if (stat(sha1_pack_name(sha1), &st))
1511                 return 0;
1512         return 1;
1513 }
1514
1515 int has_sha1_pack(const unsigned char *sha1)
1516 {
1517         struct pack_entry e;
1518         return find_pack_entry(sha1, &e);
1519 }
1520
1521 int has_sha1_file(const unsigned char *sha1)
1522 {
1523         struct stat st;
1524         struct pack_entry e;
1525
1526         if (find_pack_entry(sha1, &e))
1527                 return 1;
1528         return find_sha1_file(sha1, &st) ? 1 : 0;
1529 }
1530
1531 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1532 {
1533         unsigned long size = 4096;
1534         char *buf = malloc(size);
1535         int iret, ret;
1536         unsigned long off = 0;
1537         unsigned char hdr[50];
1538         int hdrlen;
1539         do {
1540                 iret = read(fd, buf + off, size - off);
1541                 if (iret > 0) {
1542                         off += iret;
1543                         if (off == size) {
1544                                 size *= 2;
1545                                 buf = realloc(buf, size);
1546                         }
1547                 }
1548         } while (iret > 0);
1549         if (iret < 0) {
1550                 free(buf);
1551                 return -1;
1552         }
1553         if (!type)
1554                 type = "blob";
1555         if (write_object)
1556                 ret = write_sha1_file(buf, off, type, sha1);
1557         else {
1558                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1559                 ret = 0;
1560         }
1561         free(buf);
1562         return ret;
1563 }
1564
1565 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1566 {
1567         unsigned long size = st->st_size;
1568         void *buf;
1569         int ret;
1570         unsigned char hdr[50];
1571         int hdrlen;
1572
1573         buf = "";
1574         if (size)
1575                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1576         close(fd);
1577         if (buf == MAP_FAILED)
1578                 return -1;
1579
1580         if (!type)
1581                 type = "blob";
1582         if (write_object)
1583                 ret = write_sha1_file(buf, size, type, sha1);
1584         else {
1585                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1586                 ret = 0;
1587         }
1588         if (size)
1589                 munmap(buf, size);
1590         return ret;
1591 }
1592
1593 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1594 {
1595         int fd;
1596         char *target;
1597
1598         switch (st->st_mode & S_IFMT) {
1599         case S_IFREG:
1600                 fd = open(path, O_RDONLY);
1601                 if (fd < 0)
1602                         return error("open(\"%s\"): %s", path,
1603                                      strerror(errno));
1604                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1605                         return error("%s: failed to insert into database",
1606                                      path);
1607                 break;
1608         case S_IFLNK:
1609                 target = xmalloc(st->st_size+1);
1610                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1611                         char *errstr = strerror(errno);
1612                         free(target);
1613                         return error("readlink(\"%s\"): %s", path,
1614                                      errstr);
1615                 }
1616                 if (!write_object) {
1617                         unsigned char hdr[50];
1618                         int hdrlen;
1619                         write_sha1_file_prepare(target, st->st_size, "blob",
1620                                                 sha1, hdr, &hdrlen);
1621                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1622                         return error("%s: failed to insert into database",
1623                                      path);
1624                 free(target);
1625                 break;
1626         default:
1627                 return error("%s: unsupported file type", path);
1628         }
1629         return 0;
1630 }