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 "cache.h"
  10 #include "delta.h"
  11 #include "pack.h"
  12
  13 #ifndef O_NOATIME
  14 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  15 #define O_NOATIME 01000000
  16 #else
  17 #define O_NOATIME 0
  18 #endif
  19 #endif
  20
  21 const unsigned char null_sha1[20] = { 0, };
  22
  23 static unsigned int sha1_file_open_flag = O_NOATIME;
  24
  25 static unsigned hexval(char c)
  26 {
  27         if (c >= '0' && c <= '9')
  28                 return c - '0';
  29         if (c >= 'a' && c <= 'f')
  30                 return c - 'a' + 10;
  31         if (c >= 'A' && c <= 'F')
  32                 return c - 'A' + 10;
  33         return ~0;
  34 }
  35
  36 int get_sha1_hex(const char *hex, unsigned char *sha1)
  37 {
  38         int i;
  39         for (i = 0; i < 20; i++) {
  40                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  41                 if (val & ~0xff)
  42                         return -1;
  43                 *sha1++ = val;
  44                 hex += 2;
  45         }
  46         return 0;
  47 }
  48
  49 int adjust_shared_perm(const char *path)
  50 {
  51         struct stat st;
  52         int mode;
  53
  54         if (!shared_repository)
  55                 return 0;
  56         if (lstat(path, &st) < 0)
  57                 return -1;
  58         mode = st.st_mode;
  59         if (mode & S_IRUSR)
  60                 mode |= S_IRGRP;
  61         if (mode & S_IWUSR)
  62                 mode |= S_IWGRP;
  63         if (mode & S_IXUSR)
  64                 mode |= S_IXGRP;
  65         if (S_ISDIR(mode))
  66                 mode |= S_ISGID;
  67         if (chmod(path, mode) < 0)
  68                 return -2;
  69         return 0;
  70 }
  71
  72 int safe_create_leading_directories(char *path)
  73 {
  74         char *pos = path;
  75         struct stat st;
  76
  77         if (*pos == '/')
  78                 pos++;
  79
  80         while (pos) {
  81                 pos = strchr(pos, '/');
  82                 if (!pos)
  83                         break;
  84                 *pos = 0;
  85                 if (!stat(path, &st)) {
  86                         /* path exists */
  87                         if (!S_ISDIR(st.st_mode)) {
  88                                 *pos = '/';
  89                                 return -3;
  90                         }
  91                 }
  92                 else if (mkdir(path, 0777)) {
  93                         *pos = '/';
  94                         return -1;
  95                 }
  96                 else if (adjust_shared_perm(path)) {
  97                         *pos = '/';
  98                         return -2;
  99                 }
 100                 *pos++ = '/';
 101         }
 102         return 0;
 103 }
 104
 105 char * sha1_to_hex(const unsigned char *sha1)
 106 {
 107         static char buffer[50];
 108         static const char hex[] = "0123456789abcdef";
 109         char *buf = buffer;
 110         int i;
 111
 112         for (i = 0; i < 20; i++) {
 113                 unsigned int val = *sha1++;
 114                 *buf++ = hex[val >> 4];
 115                 *buf++ = hex[val & 0xf];
 116         }
 117         *buf = '\0';
 118
 119         return buffer;
 120 }
 121
 122 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 123 {
 124         int i;
 125         for (i = 0; i < 20; i++) {
 126                 static char hex[] = "0123456789abcdef";
 127                 unsigned int val = sha1[i];
 128                 char *pos = pathbuf + i*2 + (i > 0);
 129                 *pos++ = hex[val >> 4];
 130                 *pos = hex[val & 0xf];
 131         }
 132 }
 133
 134 /*
 135  * NOTE! This returns a statically allocated buffer, so you have to be
 136  * careful about using it. Do a "strdup()" if you need to save the
 137  * filename.
 138  *
 139  * Also note that this returns the location for creating.  Reading
 140  * SHA1 file can happen from any alternate directory listed in the
 141  * DB_ENVIRONMENT environment variable if it is not found in
 142  * the primary object database.
 143  */
 144 char *sha1_file_name(const unsigned char *sha1)
 145 {
 146         static char *name, *base;
 147
 148         if (!base) {
 149                 const char *sha1_file_directory = get_object_directory();
 150                 int len = strlen(sha1_file_directory);
 151                 base = xmalloc(len + 60);
 152                 memcpy(base, sha1_file_directory, len);
 153                 memset(base+len, 0, 60);
 154                 base[len] = '/';
 155                 base[len+3] = '/';
 156                 name = base + len + 1;
 157         }
 158         fill_sha1_path(name, sha1);
 159         return base;
 160 }
 161
 162 char *sha1_pack_name(const unsigned char *sha1)
 163 {
 164         static const char hex[] = "0123456789abcdef";
 165         static char *name, *base, *buf;
 166         int i;
 167
 168         if (!base) {
 169                 const char *sha1_file_directory = get_object_directory();
 170                 int len = strlen(sha1_file_directory);
 171                 base = xmalloc(len + 60);
 172                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 173                 name = base + len + 11;
 174         }
 175
 176         buf = name;
 177
 178         for (i = 0; i < 20; i++) {
 179                 unsigned int val = *sha1++;
 180                 *buf++ = hex[val >> 4];
 181                 *buf++ = hex[val & 0xf];
 182         }
 183
 184         return base;
 185 }
 186
 187 char *sha1_pack_index_name(const unsigned char *sha1)
 188 {
 189         static const char hex[] = "0123456789abcdef";
 190         static char *name, *base, *buf;
 191         int i;
 192
 193         if (!base) {
 194                 const char *sha1_file_directory = get_object_directory();
 195                 int len = strlen(sha1_file_directory);
 196                 base = xmalloc(len + 60);
 197                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 198                 name = base + len + 11;
 199         }
 200
 201         buf = name;
 202
 203         for (i = 0; i < 20; i++) {
 204                 unsigned int val = *sha1++;
 205                 *buf++ = hex[val >> 4];
 206                 *buf++ = hex[val & 0xf];
 207         }
 208
 209         return base;
 210 }
 211
 212 struct alternate_object_database *alt_odb_list;
 213 static struct alternate_object_database **alt_odb_tail;
 214
 215 /*
 216  * Prepare alternate object database registry.
 217  *
 218  * The variable alt_odb_list points at the list of struct
 219  * alternate_object_database.  The elements on this list come from
 220  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 221  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 222  * whose contents is similar to that environment variable but can be
 223  * LF separated.  Its base points at a statically allocated buffer that
 224  * contains "/the/directory/corresponding/to/.git/objects/...", while
 225  * its name points just after the slash at the end of ".git/objects/"
 226  * in the example above, and has enough space to hold 40-byte hex
 227  * SHA1, an extra slash for the first level indirection, and the
 228  * terminating NUL.
 229  */
 230 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 231                                  const char *relative_base)
 232 {
 233         const char *cp, *last;
 234         struct alternate_object_database *ent;
 235         const char *objdir = get_object_directory();
 236         int base_len = -1;
 237
 238         last = alt;
 239         while (last < ep) {
 240                 cp = last;
 241                 if (cp < ep && *cp == '#') {
 242                         while (cp < ep && *cp != sep)
 243                                 cp++;
 244                         last = cp + 1;
 245                         continue;
 246                 }
 247                 for ( ; cp < ep && *cp != sep; cp++)
 248                         ;
 249                 if (last != cp) {
 250                         struct stat st;
 251                         struct alternate_object_database *alt;
 252                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 253                         int pfxlen = cp - last;
 254                         int entlen = pfxlen + 43;
 255
 256                         if (*last != '/' && relative_base) {
 257                                 /* Relative alt-odb */
 258                                 if (base_len < 0)
 259                                         base_len = strlen(relative_base) + 1;
 260                                 entlen += base_len;
 261                                 pfxlen += base_len;
 262                         }
 263                         ent = xmalloc(sizeof(*ent) + entlen);
 264
 265                         if (*last != '/' && relative_base) {
 266                                 memcpy(ent->base, relative_base, base_len - 1);
 267                                 ent->base[base_len - 1] = '/';
 268                                 memcpy(ent->base + base_len,
 269                                        last, cp - last);
 270                         }
 271                         else
 272                                 memcpy(ent->base, last, pfxlen);
 273
 274                         ent->name = ent->base + pfxlen + 1;
 275                         ent->base[pfxlen + 3] = '/';
 276                         ent->base[pfxlen] = ent->base[entlen-1] = 0;
 277
 278                         /* Detect cases where alternate disappeared */
 279                         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 280                                 error("object directory %s does not exist; "
 281                                       "check .git/objects/info/alternates.",
 282                                       ent->base);
 283                                 goto bad;
 284                         }
 285                         ent->base[pfxlen] = '/';
 286
 287                         /* Prevent the common mistake of listing the same
 288                          * thing twice, or object directory itself.
 289                          */
 290                         for (alt = alt_odb_list; alt; alt = alt->next)
 291                                 if (!memcmp(ent->base, alt->base, pfxlen))
 292                                         goto bad;
 293                         if (!memcmp(ent->base, objdir, pfxlen)) {
 294                         bad:
 295                                 free(ent);
 296                         }
 297                         else {
 298                                 *alt_odb_tail = ent;
 299                                 alt_odb_tail = &(ent->next);
 300                                 ent->next = NULL;
 301                         }
 302                 }
 303                 while (cp < ep && *cp == sep)
 304                         cp++;
 305                 last = cp;
 306         }
 307 }
 308
 309 void prepare_alt_odb(void)
 310 {
 311         char path[PATH_MAX];
 312         char *map;
 313         int fd;
 314         struct stat st;
 315         char *alt;
 316
 317         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 318         if (!alt) alt = "";
 319
 320         if (alt_odb_tail)
 321                 return;
 322         alt_odb_tail = &alt_odb_list;
 323         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 324
 325         sprintf(path, "%s/info/alternates", get_object_directory());
 326         fd = open(path, O_RDONLY);
 327         if (fd < 0)
 328                 return;
 329         if (fstat(fd, &st) || (st.st_size == 0)) {
 330                 close(fd);
 331                 return;
 332         }
 333         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 334         close(fd);
 335         if (map == MAP_FAILED)
 336                 return;
 337
 338         link_alt_odb_entries(map, map + st.st_size, '\n',
 339                              get_object_directory());
 340         munmap(map, st.st_size);
 341 }
 342
 343 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 344 {
 345         char *name = sha1_file_name(sha1);
 346         struct alternate_object_database *alt;
 347
 348         if (!stat(name, st))
 349                 return name;
 350         prepare_alt_odb();
 351         for (alt = alt_odb_list; alt; alt = alt->next) {
 352                 name = alt->name;
 353                 fill_sha1_path(name, sha1);
 354                 if (!stat(alt->base, st))
 355                         return alt->base;
 356         }
 357         return NULL;
 358 }
 359
 360 #define PACK_MAX_SZ (1<<26)
 361 static int pack_used_ctr;
 362 static unsigned long pack_mapped;
 363 struct packed_git *packed_git;
 364
 365 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 366                                 void **idx_map_)
 367 {
 368         void *idx_map;
 369         unsigned int *index;
 370         unsigned long idx_size;
 371         int nr, i;
 372         int fd = open(path, O_RDONLY);
 373         struct stat st;
 374         if (fd < 0)
 375                 return -1;
 376         if (fstat(fd, &st)) {
 377                 close(fd);
 378                 return -1;
 379         }
 380         idx_size = st.st_size;
 381         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 382         close(fd);
 383         if (idx_map == MAP_FAILED)
 384                 return -1;
 385
 386         index = idx_map;
 387         *idx_map_ = idx_map;
 388         *idx_size_ = idx_size;
 389
 390         /* check index map */
 391         if (idx_size < 4*256 + 20 + 20)
 392                 return error("index file too small");
 393         nr = 0;
 394         for (i = 0; i < 256; i++) {
 395                 unsigned int n = ntohl(index[i]);
 396                 if (n < nr)
 397                         return error("non-monotonic index");
 398                 nr = n;
 399         }
 400
 401         /*
 402          * Total size:
 403          *  - 256 index entries 4 bytes each
 404          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 405          *  - 20-byte SHA1 of the packfile
 406          *  - 20-byte SHA1 file checksum
 407          */
 408         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 409                 return error("wrong index file size");
 410
 411         return 0;
 412 }
 413
 414 static int unuse_one_packed_git(void)
 415 {
 416         struct packed_git *p, *lru = NULL;
 417
 418         for (p = packed_git; p; p = p->next) {
 419                 if (p->pack_use_cnt || !p->pack_base)
 420                         continue;
 421                 if (!lru || p->pack_last_used < lru->pack_last_used)
 422                         lru = p;
 423         }
 424         if (!lru)
 425                 return 0;
 426         munmap(lru->pack_base, lru->pack_size);
 427         lru->pack_base = NULL;
 428         return 1;
 429 }
 430
 431 void unuse_packed_git(struct packed_git *p)
 432 {
 433         p->pack_use_cnt--;
 434 }
 435
 436 int use_packed_git(struct packed_git *p)
 437 {
 438         if (!p->pack_size) {
 439                 struct stat st;
 440                 // We created the struct before we had the pack
 441                 stat(p->pack_name, &st);
 442                 if (!S_ISREG(st.st_mode))
 443                         die("packfile %s not a regular file", p->pack_name);
 444                 p->pack_size = st.st_size;
 445         }
 446         if (!p->pack_base) {
 447                 int fd;
 448                 struct stat st;
 449                 void *map;
 450
 451                 pack_mapped += p->pack_size;
 452                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 453                         ; /* nothing */
 454                 fd = open(p->pack_name, O_RDONLY);
 455                 if (fd < 0)
 456                         die("packfile %s cannot be opened", p->pack_name);
 457                 if (fstat(fd, &st)) {
 458                         close(fd);
 459                         die("packfile %s cannot be opened", p->pack_name);
 460                 }
 461                 if (st.st_size != p->pack_size)
 462                         die("packfile %s size mismatch.", p->pack_name);
 463                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 464                 close(fd);
 465                 if (map == MAP_FAILED)
 466                         die("packfile %s cannot be mapped.", p->pack_name);
 467                 p->pack_base = map;
 468
 469                 /* Check if the pack file matches with the index file.
 470                  * this is cheap.
 471                  */
 472                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 473                            p->pack_base + p->pack_size - 20, 20)) {
 474
 475                         die("packfile %s does not match index.", p->pack_name);
 476                 }
 477         }
 478         p->pack_last_used = pack_used_ctr++;
 479         p->pack_use_cnt++;
 480         return 0;
 481 }
 482
 483 struct packed_git *add_packed_git(char *path, int path_len, int local)
 484 {
 485         struct stat st;
 486         struct packed_git *p;
 487         unsigned long idx_size;
 488         void *idx_map;
 489         unsigned char sha1[20];
 490
 491         if (check_packed_git_idx(path, &idx_size, &idx_map))
 492                 return NULL;
 493
 494         /* do we have a corresponding .pack file? */
 495         strcpy(path + path_len - 4, ".pack");
 496         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 497                 munmap(idx_map, idx_size);
 498                 return NULL;
 499         }
 500         /* ok, it looks sane as far as we can check without
 501          * actually mapping the pack file.
 502          */
 503         p = xmalloc(sizeof(*p) + path_len + 2);
 504         strcpy(p->pack_name, path);
 505         p->index_size = idx_size;
 506         p->pack_size = st.st_size;
 507         p->index_base = idx_map;
 508         p->next = NULL;
 509         p->pack_base = NULL;
 510         p->pack_last_used = 0;
 511         p->pack_use_cnt = 0;
 512         p->pack_local = local;
 513         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 514                 memcpy(p->sha1, sha1, 20);
 515         return p;
 516 }
 517
 518 struct packed_git *parse_pack_index(unsigned char *sha1)
 519 {
 520         char *path = sha1_pack_index_name(sha1);
 521         return parse_pack_index_file(sha1, path);
 522 }
 523
 524 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 525 {
 526         struct packed_git *p;
 527         unsigned long idx_size;
 528         void *idx_map;
 529         char *path;
 530
 531         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 532                 return NULL;
 533
 534         path = sha1_pack_name(sha1);
 535
 536         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 537         strcpy(p->pack_name, path);
 538         p->index_size = idx_size;
 539         p->pack_size = 0;
 540         p->index_base = idx_map;
 541         p->next = NULL;
 542         p->pack_base = NULL;
 543         p->pack_last_used = 0;
 544         p->pack_use_cnt = 0;
 545         memcpy(p->sha1, sha1, 20);
 546         return p;
 547 }
 548
 549 void install_packed_git(struct packed_git *pack)
 550 {
 551         pack->next = packed_git;
 552         packed_git = pack;
 553 }
 554
 555 static void prepare_packed_git_one(char *objdir, int local)
 556 {
 557         char path[PATH_MAX];
 558         int len;
 559         DIR *dir;
 560         struct dirent *de;
 561
 562         sprintf(path, "%s/pack", objdir);
 563         len = strlen(path);
 564         dir = opendir(path);
 565         if (!dir) {
 566                 if (errno != ENOENT)
 567                         error("unable to open object pack directory: %s: %s\n",
 568                               path, strerror(errno));
 569                 return;
 570         }
 571         path[len++] = '/';
 572         while ((de = readdir(dir)) != NULL) {
 573                 int namelen = strlen(de->d_name);
 574                 struct packed_git *p;
 575
 576                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 577                         continue;
 578
 579                 /* we have .idx.  Is it a file we can map? */
 580                 strcpy(path + len, de->d_name);
 581                 p = add_packed_git(path, len + namelen, local);
 582                 if (!p)
 583                         continue;
 584                 p->next = packed_git;
 585                 packed_git = p;
 586         }
 587         closedir(dir);
 588 }
 589
 590 void prepare_packed_git(void)
 591 {
 592         static int run_once = 0;
 593         struct alternate_object_database *alt;
 594
 595         if (run_once)
 596                 return;
 597         prepare_packed_git_one(get_object_directory(), 1);
 598         prepare_alt_odb();
 599         for (alt = alt_odb_list; alt; alt = alt->next) {
 600                 alt->name[-1] = 0;
 601                 prepare_packed_git_one(alt->base, 0);
 602                 alt->name[-1] = '/';
 603         }
 604         run_once = 1;
 605 }
 606
 607 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 608 {
 609         char header[100];
 610         unsigned char real_sha1[20];
 611         SHA_CTX c;
 612
 613         SHA1_Init(&c);
 614         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 615         SHA1_Update(&c, map, size);
 616         SHA1_Final(real_sha1, &c);
 617         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 618 }
 619
 620 static void *map_sha1_file_internal(const unsigned char *sha1,
 621                                     unsigned long *size)
 622 {
 623         struct stat st;
 624         void *map;
 625         int fd;
 626         char *filename = find_sha1_file(sha1, &st);
 627
 628         if (!filename) {
 629                 return NULL;
 630         }
 631
 632         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 633         if (fd < 0) {
 634                 /* See if it works without O_NOATIME */
 635                 switch (sha1_file_open_flag) {
 636                 default:
 637                         fd = open(filename, O_RDONLY);
 638                         if (fd >= 0)
 639                                 break;
 640                 /* Fallthrough */
 641                 case 0:
 642                         return NULL;
 643                 }
 644
 645                 /* If it failed once, it will probably fail again.
 646                  * Stop using O_NOATIME
 647                  */
 648                 sha1_file_open_flag = 0;
 649         }
 650         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 651         close(fd);
 652         if (map == MAP_FAILED)
 653                 return NULL;
 654         *size = st.st_size;
 655         return map;
 656 }
 657
 658 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 659 {
 660         /* Get the data stream */
 661         memset(stream, 0, sizeof(*stream));
 662         stream->next_in = map;
 663         stream->avail_in = mapsize;
 664         stream->next_out = buffer;
 665         stream->avail_out = size;
 666
 667         inflateInit(stream);
 668         return inflate(stream, 0);
 669 }
 670
 671 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 672 {
 673         int bytes = strlen(buffer) + 1;
 674         unsigned char *buf = xmalloc(1+size);
 675
 676         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 677         bytes = stream->total_out - bytes;
 678         if (bytes < size) {
 679                 stream->next_out = buf + bytes;
 680                 stream->avail_out = size - bytes;
 681                 while (inflate(stream, Z_FINISH) == Z_OK)
 682                         /* nothing */;
 683         }
 684         buf[size] = 0;
 685         inflateEnd(stream);
 686         return buf;
 687 }
 688
 689 /*
 690  * We used to just use "sscanf()", but that's actually way
 691  * too permissive for what we want to check. So do an anal
 692  * object header parse by hand.
 693  */
 694 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 695 {
 696         int i;
 697         unsigned long size;
 698
 699         /*
 700          * The type can be at most ten bytes (including the
 701          * terminating '\0' that we add), and is followed by
 702          * a space.
 703          */
 704         i = 10;
 705         for (;;) {
 706                 char c = *hdr++;
 707                 if (c == ' ')
 708                         break;
 709                 if (!--i)
 710                         return -1;
 711                 *type++ = c;
 712         }
 713         *type = 0;
 714
 715         /*
 716          * The length must follow immediately, and be in canonical
 717          * decimal format (ie "010" is not valid).
 718          */
 719         size = *hdr++ - '0';
 720         if (size > 9)
 721                 return -1;
 722         if (size) {
 723                 for (;;) {
 724                         unsigned long c = *hdr - '0';
 725                         if (c > 9)
 726                                 break;
 727                         hdr++;
 728                         size = size * 10 + c;
 729                 }
 730         }
 731         *sizep = size;
 732
 733         /*
 734          * The length must be followed by a zero byte
 735          */
 736         return *hdr ? -1 : 0;
 737 }
 738
 739 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 740 {
 741         int ret;
 742         z_stream stream;
 743         char hdr[8192];
 744
 745         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 746         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 747                 return NULL;
 748
 749         return unpack_sha1_rest(&stream, hdr, *size);
 750 }
 751
 752 /* forward declaration for a mutually recursive function */
 753 static int packed_object_info(struct pack_entry *entry,
 754                               char *type, unsigned long *sizep);
 755
 756 static int packed_delta_info(unsigned char *base_sha1,
 757                              unsigned long delta_size,
 758                              unsigned long left,
 759                              char *type,
 760                              unsigned long *sizep,
 761                              struct packed_git *p)
 762 {
 763         struct pack_entry base_ent;
 764
 765         if (left < 20)
 766                 die("truncated pack file");
 767
 768         /* The base entry _must_ be in the same pack */
 769         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 770                 die("failed to find delta-pack base object %s",
 771                     sha1_to_hex(base_sha1));
 772
 773         /* We choose to only get the type of the base object and
 774          * ignore potentially corrupt pack file that expects the delta
 775          * based on a base with a wrong size.  This saves tons of
 776          * inflate() calls.
 777          */
 778
 779         if (packed_object_info(&base_ent, type, NULL))
 780                 die("cannot get info for delta-pack base");
 781
 782         if (sizep) {
 783                 const unsigned char *data;
 784                 unsigned char delta_head[64];
 785                 unsigned long result_size;
 786                 z_stream stream;
 787                 int st;
 788
 789                 memset(&stream, 0, sizeof(stream));
 790
 791                 data = stream.next_in = base_sha1 + 20;
 792                 stream.avail_in = left - 20;
 793                 stream.next_out = delta_head;
 794                 stream.avail_out = sizeof(delta_head);
 795
 796                 inflateInit(&stream);
 797                 st = inflate(&stream, Z_FINISH);
 798                 inflateEnd(&stream);
 799                 if ((st != Z_STREAM_END) &&
 800                     stream.total_out != sizeof(delta_head))
 801                         die("delta data unpack-initial failed");
 802
 803                 /* Examine the initial part of the delta to figure out
 804                  * the result size.
 805                  */
 806                 data = delta_head;
 807                 get_delta_hdr_size(&data); /* ignore base size */
 808
 809                 /* Read the result size */
 810                 result_size = get_delta_hdr_size(&data);
 811                 *sizep = result_size;
 812         }
 813         return 0;
 814 }
 815
 816 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 817         enum object_type *type, unsigned long *sizep)
 818 {
 819         unsigned shift;
 820         unsigned char *pack, c;
 821         unsigned long size;
 822
 823         if (offset >= p->pack_size)
 824                 die("object offset outside of pack file");
 825
 826         pack =  p->pack_base + offset;
 827         c = *pack++;
 828         offset++;
 829         *type = (c >> 4) & 7;
 830         size = c & 15;
 831         shift = 4;
 832         while (c & 0x80) {
 833                 if (offset >= p->pack_size)
 834                         die("object offset outside of pack file");
 835                 c = *pack++;
 836                 offset++;
 837                 size += (c & 0x7f) << shift;
 838                 shift += 7;
 839         }
 840         *sizep = size;
 841         return offset;
 842 }
 843
 844 void packed_object_info_detail(struct pack_entry *e,
 845                                char *type,
 846                                unsigned long *size,
 847                                unsigned long *store_size,
 848                                int *delta_chain_length,
 849                                unsigned char *base_sha1)
 850 {
 851         struct packed_git *p = e->p;
 852         unsigned long offset, left;
 853         unsigned char *pack;
 854         enum object_type kind;
 855
 856         offset = unpack_object_header(p, e->offset, &kind, size);
 857         pack = p->pack_base + offset;
 858         left = p->pack_size - offset;
 859         if (kind != OBJ_DELTA)
 860                 *delta_chain_length = 0;
 861         else {
 862                 int chain_length = 0;
 863                 memcpy(base_sha1, pack, 20);
 864                 do {
 865                         struct pack_entry base_ent;
 866                         unsigned long junk;
 867
 868                         find_pack_entry_one(pack, &base_ent, p);
 869                         offset = unpack_object_header(p, base_ent.offset,
 870                                                       &kind, &junk);
 871                         pack = p->pack_base + offset;
 872                         chain_length++;
 873                 } while (kind == OBJ_DELTA);
 874                 *delta_chain_length = chain_length;
 875         }
 876         switch (kind) {
 877         case OBJ_COMMIT:
 878                 strcpy(type, "commit");
 879                 break;
 880         case OBJ_TREE:
 881                 strcpy(type, "tree");
 882                 break;
 883         case OBJ_BLOB:
 884                 strcpy(type, "blob");
 885                 break;
 886         case OBJ_TAG:
 887                 strcpy(type, "tag");
 888                 break;
 889         default:
 890                 die("corrupted pack file %s containing object of kind %d",
 891                     p->pack_name, kind);
 892         }
 893         *store_size = 0; /* notyet */
 894 }
 895
 896 static int packed_object_info(struct pack_entry *entry,
 897                               char *type, unsigned long *sizep)
 898 {
 899         struct packed_git *p = entry->p;
 900         unsigned long offset, size, left;
 901         unsigned char *pack;
 902         enum object_type kind;
 903         int retval;
 904
 905         if (use_packed_git(p))
 906                 die("cannot map packed file");
 907
 908         offset = unpack_object_header(p, entry->offset, &kind, &size);
 909         pack = p->pack_base + offset;
 910         left = p->pack_size - offset;
 911
 912         switch (kind) {
 913         case OBJ_DELTA:
 914                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 915                 unuse_packed_git(p);
 916                 return retval;
 917         case OBJ_COMMIT:
 918                 strcpy(type, "commit");
 919                 break;
 920         case OBJ_TREE:
 921                 strcpy(type, "tree");
 922                 break;
 923         case OBJ_BLOB:
 924                 strcpy(type, "blob");
 925                 break;
 926         case OBJ_TAG:
 927                 strcpy(type, "tag");
 928                 break;
 929         default:
 930                 die("corrupted pack file %s containing object of kind %d",
 931                     p->pack_name, kind);
 932         }
 933         if (sizep)
 934                 *sizep = size;
 935         unuse_packed_git(p);
 936         return 0;
 937 }
 938
 939 /* forward declaration for a mutually recursive function */
 940 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 941
 942 static void *unpack_delta_entry(unsigned char *base_sha1,
 943                                 unsigned long delta_size,
 944                                 unsigned long left,
 945                                 char *type,
 946                                 unsigned long *sizep,
 947                                 struct packed_git *p)
 948 {
 949         struct pack_entry base_ent;
 950         void *data, *delta_data, *result, *base;
 951         unsigned long data_size, result_size, base_size;
 952         z_stream stream;
 953         int st;
 954
 955         if (left < 20)
 956                 die("truncated pack file");
 957         data = base_sha1 + 20;
 958         data_size = left - 20;
 959         delta_data = xmalloc(delta_size);
 960
 961         memset(&stream, 0, sizeof(stream));
 962
 963         stream.next_in = data;
 964         stream.avail_in = data_size;
 965         stream.next_out = delta_data;
 966         stream.avail_out = delta_size;
 967
 968         inflateInit(&stream);
 969         st = inflate(&stream, Z_FINISH);
 970         inflateEnd(&stream);
 971         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 972                 die("delta data unpack failed");
 973
 974         /* The base entry _must_ be in the same pack */
 975         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 976                 die("failed to find delta-pack base object %s",
 977                     sha1_to_hex(base_sha1));
 978         base = unpack_entry_gently(&base_ent, type, &base_size);
 979         if (!base)
 980                 die("failed to read delta-pack base object %s",
 981                     sha1_to_hex(base_sha1));
 982         result = patch_delta(base, base_size,
 983                              delta_data, delta_size,
 984                              &result_size);
 985         if (!result)
 986                 die("failed to apply delta");
 987         free(delta_data);
 988         free(base);
 989         *sizep = result_size;
 990         return result;
 991 }
 992
 993 static void *unpack_non_delta_entry(unsigned char *data,
 994                                     unsigned long size,
 995                                     unsigned long left)
 996 {
 997         int st;
 998         z_stream stream;
 999         unsigned char *buffer;
1000
1001         buffer = xmalloc(size + 1);
1002         buffer[size] = 0;
1003         memset(&stream, 0, sizeof(stream));
1004         stream.next_in = data;
1005         stream.avail_in = left;
1006         stream.next_out = buffer;
1007         stream.avail_out = size;
1008
1009         inflateInit(&stream);
1010         st = inflate(&stream, Z_FINISH);
1011         inflateEnd(&stream);
1012         if ((st != Z_STREAM_END) || stream.total_out != size) {
1013                 free(buffer);
1014                 return NULL;
1015         }
1016
1017         return buffer;
1018 }
1019
1020 static void *unpack_entry(struct pack_entry *entry,
1021                           char *type, unsigned long *sizep)
1022 {
1023         struct packed_git *p = entry->p;
1024         void *retval;
1025
1026         if (use_packed_git(p))
1027                 die("cannot map packed file");
1028         retval = unpack_entry_gently(entry, type, sizep);
1029         unuse_packed_git(p);
1030         if (!retval)
1031                 die("corrupted pack file %s", p->pack_name);
1032         return retval;
1033 }
1034
1035 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1036 void *unpack_entry_gently(struct pack_entry *entry,
1037                           char *type, unsigned long *sizep)
1038 {
1039         struct packed_git *p = entry->p;
1040         unsigned long offset, size, left;
1041         unsigned char *pack;
1042         enum object_type kind;
1043         void *retval;
1044
1045         offset = unpack_object_header(p, entry->offset, &kind, &size);
1046         pack = p->pack_base + offset;
1047         left = p->pack_size - offset;
1048         switch (kind) {
1049         case OBJ_DELTA:
1050                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1051                 return retval;
1052         case OBJ_COMMIT:
1053                 strcpy(type, "commit");
1054                 break;
1055         case OBJ_TREE:
1056                 strcpy(type, "tree");
1057                 break;
1058         case OBJ_BLOB:
1059                 strcpy(type, "blob");
1060                 break;
1061         case OBJ_TAG:
1062                 strcpy(type, "tag");
1063                 break;
1064         default:
1065                 return NULL;
1066         }
1067         *sizep = size;
1068         retval = unpack_non_delta_entry(pack, size, left);
1069         return retval;
1070 }
1071
1072 int num_packed_objects(const struct packed_git *p)
1073 {
1074         /* See check_packed_git_idx() */
1075         return (p->index_size - 20 - 20 - 4*256) / 24;
1076 }
1077
1078 int nth_packed_object_sha1(const struct packed_git *p, int n,
1079                            unsigned char* sha1)
1080 {
1081         void *index = p->index_base + 256;
1082         if (n < 0 || num_packed_objects(p) <= n)
1083                 return -1;
1084         memcpy(sha1, (index + 24 * n + 4), 20);
1085         return 0;
1086 }
1087
1088 int find_pack_entry_one(const unsigned char *sha1,
1089                         struct pack_entry *e, struct packed_git *p)
1090 {
1091         unsigned int *level1_ofs = p->index_base;
1092         int hi = ntohl(level1_ofs[*sha1]);
1093         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1094         void *index = p->index_base + 256;
1095
1096         do {
1097                 int mi = (lo + hi) / 2;
1098                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1099                 if (!cmp) {
1100                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1101                         memcpy(e->sha1, sha1, 20);
1102                         e->p = p;
1103                         return 1;
1104                 }
1105                 if (cmp > 0)
1106                         hi = mi;
1107                 else
1108                         lo = mi+1;
1109         } while (lo < hi);
1110         return 0;
1111 }
1112
1113 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1114 {
1115         struct packed_git *p;
1116         prepare_packed_git();
1117
1118         for (p = packed_git; p; p = p->next) {
1119                 if (find_pack_entry_one(sha1, e, p))
1120                         return 1;
1121         }
1122         return 0;
1123 }
1124
1125 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1126                                   struct packed_git *packs)
1127 {
1128         struct packed_git *p;
1129         struct pack_entry e;
1130
1131         for (p = packs; p; p = p->next) {
1132                 if (find_pack_entry_one(sha1, &e, p))
1133                         return p;
1134         }
1135         return NULL;
1136
1137 }
1138
1139 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1140 {
1141         int status;
1142         unsigned long mapsize, size;
1143         void *map;
1144         z_stream stream;
1145         char hdr[128];
1146
1147         map = map_sha1_file_internal(sha1, &mapsize);
1148         if (!map) {
1149                 struct pack_entry e;
1150
1151                 if (!find_pack_entry(sha1, &e))
1152                         return error("unable to find %s", sha1_to_hex(sha1));
1153                 return packed_object_info(&e, type, sizep);
1154         }
1155         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1156                 status = error("unable to unpack %s header",
1157                                sha1_to_hex(sha1));
1158         if (parse_sha1_header(hdr, type, &size) < 0)
1159                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1160         else {
1161                 status = 0;
1162                 if (sizep)
1163                         *sizep = size;
1164         }
1165         inflateEnd(&stream);
1166         munmap(map, mapsize);
1167         return status;
1168 }
1169
1170 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1171 {
1172         struct pack_entry e;
1173
1174         if (!find_pack_entry(sha1, &e)) {
1175                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1176                 return NULL;
1177         }
1178         return unpack_entry(&e, type, size);
1179 }
1180
1181 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1182 {
1183         unsigned long mapsize;
1184         void *map, *buf;
1185         struct pack_entry e;
1186
1187         if (find_pack_entry(sha1, &e))
1188                 return read_packed_sha1(sha1, type, size);
1189         map = map_sha1_file_internal(sha1, &mapsize);
1190         if (map) {
1191                 buf = unpack_sha1_file(map, mapsize, type, size);
1192                 munmap(map, mapsize);
1193                 return buf;
1194         }
1195         return NULL;
1196 }
1197
1198 void *read_object_with_reference(const unsigned char *sha1,
1199                                  const char *required_type,
1200                                  unsigned long *size,
1201                                  unsigned char *actual_sha1_return)
1202 {
1203         char type[20];
1204         void *buffer;
1205         unsigned long isize;
1206         unsigned char actual_sha1[20];
1207
1208         memcpy(actual_sha1, sha1, 20);
1209         while (1) {
1210                 int ref_length = -1;
1211                 const char *ref_type = NULL;
1212
1213                 buffer = read_sha1_file(actual_sha1, type, &isize);
1214                 if (!buffer)
1215                         return NULL;
1216                 if (!strcmp(type, required_type)) {
1217                         *size = isize;
1218                         if (actual_sha1_return)
1219                                 memcpy(actual_sha1_return, actual_sha1, 20);
1220                         return buffer;
1221                 }
1222                 /* Handle references */
1223                 else if (!strcmp(type, "commit"))
1224                         ref_type = "tree ";
1225                 else if (!strcmp(type, "tag"))
1226                         ref_type = "object ";
1227                 else {
1228                         free(buffer);
1229                         return NULL;
1230                 }
1231                 ref_length = strlen(ref_type);
1232
1233                 if (memcmp(buffer, ref_type, ref_length) ||
1234                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1235                         free(buffer);
1236                         return NULL;
1237                 }
1238                 free(buffer);
1239                 /* Now we have the ID of the referred-to object in
1240                  * actual_sha1.  Check again. */
1241         }
1242 }
1243
1244 char *write_sha1_file_prepare(void *buf,
1245                               unsigned long len,
1246                               const char *type,
1247                               unsigned char *sha1,
1248                               unsigned char *hdr,
1249                               int *hdrlen)
1250 {
1251         SHA_CTX c;
1252
1253         /* Generate the header */
1254         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1255
1256         /* Sha1.. */
1257         SHA1_Init(&c);
1258         SHA1_Update(&c, hdr, *hdrlen);
1259         SHA1_Update(&c, buf, len);
1260         SHA1_Final(sha1, &c);
1261
1262         return sha1_file_name(sha1);
1263 }
1264
1265 /*
1266  * Link the tempfile to the final place, possibly creating the
1267  * last directory level as you do so.
1268  *
1269  * Returns the errno on failure, 0 on success.
1270  */
1271 static int link_temp_to_file(const char *tmpfile, char *filename)
1272 {
1273         int ret;
1274
1275         if (!link(tmpfile, filename))
1276                 return 0;
1277
1278         /*
1279          * Try to mkdir the last path component if that failed
1280          * with an ENOENT.
1281          *
1282          * Re-try the "link()" regardless of whether the mkdir
1283          * succeeds, since a race might mean that somebody
1284          * else succeeded.
1285          */
1286         ret = errno;
1287         if (ret == ENOENT) {
1288                 char *dir = strrchr(filename, '/');
1289                 if (dir) {
1290                         *dir = 0;
1291                         mkdir(filename, 0777);
1292                         if (adjust_shared_perm(filename))
1293                                 return -2;
1294                         *dir = '/';
1295                         if (!link(tmpfile, filename))
1296                                 return 0;
1297                         ret = errno;
1298                 }
1299         }
1300         return ret;
1301 }
1302
1303 /*
1304  * Move the just written object into its final resting place
1305  */
1306 int move_temp_to_file(const char *tmpfile, char *filename)
1307 {
1308         int ret = link_temp_to_file(tmpfile, filename);
1309
1310         /*
1311          * Coda hack - coda doesn't like cross-directory links,
1312          * so we fall back to a rename, which will mean that it
1313          * won't be able to check collisions, but that's not a
1314          * big deal.
1315          *
1316          * The same holds for FAT formatted media.
1317          *
1318          * When this succeeds, we just return 0. We have nothing
1319          * left to unlink.
1320          */
1321         if (ret && ret != EEXIST) {
1322                 if (!rename(tmpfile, filename))
1323                         return 0;
1324                 ret = errno;
1325         }
1326         unlink(tmpfile);
1327         if (ret) {
1328                 if (ret != EEXIST) {
1329                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1330                         return -1;
1331                 }
1332                 /* FIXME!!! Collision check here ? */
1333         }
1334
1335         return 0;
1336 }
1337
1338 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1339 {
1340         int size;
1341         unsigned char *compressed;
1342         z_stream stream;
1343         unsigned char sha1[20];
1344         char *filename;
1345         static char tmpfile[PATH_MAX];
1346         unsigned char hdr[50];
1347         int fd, hdrlen;
1348
1349         /* Normally if we have it in the pack then we do not bother writing
1350          * it out into .git/objects/??/?{38} file.
1351          */
1352         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1353         if (returnsha1)
1354                 memcpy(returnsha1, sha1, 20);
1355         if (has_sha1_file(sha1))
1356                 return 0;
1357         fd = open(filename, O_RDONLY);
1358         if (fd >= 0) {
1359                 /*
1360                  * FIXME!!! We might do collision checking here, but we'd
1361                  * need to uncompress the old file and check it. Later.
1362                  */
1363                 close(fd);
1364                 return 0;
1365         }
1366
1367         if (errno != ENOENT) {
1368                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1369                 return -1;
1370         }
1371
1372         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1373
1374         fd = mkstemp(tmpfile);
1375         if (fd < 0) {
1376                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1377                 return -1;
1378         }
1379
1380         /* Set it up */
1381         memset(&stream, 0, sizeof(stream));
1382         deflateInit(&stream, Z_BEST_COMPRESSION);
1383         size = deflateBound(&stream, len+hdrlen);
1384         compressed = xmalloc(size);
1385
1386         /* Compress it */
1387         stream.next_out = compressed;
1388         stream.avail_out = size;
1389
1390         /* First header.. */
1391         stream.next_in = hdr;
1392         stream.avail_in = hdrlen;
1393         while (deflate(&stream, 0) == Z_OK)
1394                 /* nothing */;
1395
1396         /* Then the data itself.. */
1397         stream.next_in = buf;
1398         stream.avail_in = len;
1399         while (deflate(&stream, Z_FINISH) == Z_OK)
1400                 /* nothing */;
1401         deflateEnd(&stream);
1402         size = stream.total_out;
1403
1404         if (write(fd, compressed, size) != size)
1405                 die("unable to write file");
1406         fchmod(fd, 0444);
1407         close(fd);
1408         free(compressed);
1409
1410         return move_temp_to_file(tmpfile, filename);
1411 }
1412
1413 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1414 {
1415         ssize_t size;
1416         unsigned long objsize;
1417         int posn = 0;
1418         void *map = map_sha1_file_internal(sha1, &objsize);
1419         void *buf = map;
1420         void *temp_obj = NULL;
1421         z_stream stream;
1422
1423         if (!buf) {
1424                 unsigned char *unpacked;
1425                 unsigned long len;
1426                 char type[20];
1427                 char hdr[50];
1428                 int hdrlen;
1429                 // need to unpack and recompress it by itself
1430                 unpacked = read_packed_sha1(sha1, type, &len);
1431
1432                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1433
1434                 /* Set it up */
1435                 memset(&stream, 0, sizeof(stream));
1436                 deflateInit(&stream, Z_BEST_COMPRESSION);
1437                 size = deflateBound(&stream, len + hdrlen);
1438                 temp_obj = buf = xmalloc(size);
1439
1440                 /* Compress it */
1441                 stream.next_out = buf;
1442                 stream.avail_out = size;
1443
1444                 /* First header.. */
1445                 stream.next_in = (void *)hdr;
1446                 stream.avail_in = hdrlen;
1447                 while (deflate(&stream, 0) == Z_OK)
1448                         /* nothing */;
1449
1450                 /* Then the data itself.. */
1451                 stream.next_in = unpacked;
1452                 stream.avail_in = len;
1453                 while (deflate(&stream, Z_FINISH) == Z_OK)
1454                         /* nothing */;
1455                 deflateEnd(&stream);
1456                 free(unpacked);
1457
1458                 objsize = stream.total_out;
1459         }
1460
1461         do {
1462                 size = write(fd, buf + posn, objsize - posn);
1463                 if (size <= 0) {
1464                         if (!size) {
1465                                 fprintf(stderr, "write closed\n");
1466                         } else {
1467                                 perror("write ");
1468                         }
1469                         return -1;
1470                 }
1471                 posn += size;
1472         } while (posn < objsize);
1473
1474         if (map)
1475                 munmap(map, objsize);
1476         if (temp_obj)
1477                 free(temp_obj);
1478
1479         return 0;
1480 }
1481
1482 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1483                        size_t bufsize, size_t *bufposn)
1484 {
1485         char tmpfile[PATH_MAX];
1486         int local;
1487         z_stream stream;
1488         unsigned char real_sha1[20];
1489         unsigned char discard[4096];
1490         int ret;
1491         SHA_CTX c;
1492
1493         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1494
1495         local = mkstemp(tmpfile);
1496         if (local < 0)
1497                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1498
1499         memset(&stream, 0, sizeof(stream));
1500
1501         inflateInit(&stream);
1502
1503         SHA1_Init(&c);
1504
1505         do {
1506                 ssize_t size;
1507                 if (*bufposn) {
1508                         stream.avail_in = *bufposn;
1509                         stream.next_in = (unsigned char *) buffer;
1510                         do {
1511                                 stream.next_out = discard;
1512                                 stream.avail_out = sizeof(discard);
1513                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1514                                 SHA1_Update(&c, discard, sizeof(discard) -
1515                                             stream.avail_out);
1516                         } while (stream.avail_in && ret == Z_OK);
1517                         write(local, buffer, *bufposn - stream.avail_in);
1518                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1519                                 stream.avail_in);
1520                         *bufposn = stream.avail_in;
1521                         if (ret != Z_OK)
1522                                 break;
1523                 }
1524                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1525                 if (size <= 0) {
1526                         close(local);
1527                         unlink(tmpfile);
1528                         if (!size)
1529                                 return error("Connection closed?");
1530                         perror("Reading from connection");
1531                         return -1;
1532                 }
1533                 *bufposn += size;
1534         } while (1);
1535         inflateEnd(&stream);
1536
1537         close(local);
1538         SHA1_Final(real_sha1, &c);
1539         if (ret != Z_STREAM_END) {
1540                 unlink(tmpfile);
1541                 return error("File %s corrupted", sha1_to_hex(sha1));
1542         }
1543         if (memcmp(sha1, real_sha1, 20)) {
1544                 unlink(tmpfile);
1545                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1546         }
1547
1548         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1549 }
1550
1551 int has_pack_index(const unsigned char *sha1)
1552 {
1553         struct stat st;
1554         if (stat(sha1_pack_index_name(sha1), &st))
1555                 return 0;
1556         return 1;
1557 }
1558
1559 int has_pack_file(const unsigned char *sha1)
1560 {
1561         struct stat st;
1562         if (stat(sha1_pack_name(sha1), &st))
1563                 return 0;
1564         return 1;
1565 }
1566
1567 int has_sha1_pack(const unsigned char *sha1)
1568 {
1569         struct pack_entry e;
1570         return find_pack_entry(sha1, &e);
1571 }
1572
1573 int has_sha1_file(const unsigned char *sha1)
1574 {
1575         struct stat st;
1576         struct pack_entry e;
1577
1578         if (find_pack_entry(sha1, &e))
1579                 return 1;
1580         return find_sha1_file(sha1, &st) ? 1 : 0;
1581 }
1582
1583 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1584 {
1585         unsigned long size = 4096;
1586         char *buf = malloc(size);
1587         int iret, ret;
1588         unsigned long off = 0;
1589         unsigned char hdr[50];
1590         int hdrlen;
1591         do {
1592                 iret = read(fd, buf + off, size - off);
1593                 if (iret > 0) {
1594                         off += iret;
1595                         if (off == size) {
1596                                 size *= 2;
1597                                 buf = realloc(buf, size);
1598                         }
1599                 }
1600         } while (iret > 0);
1601         if (iret < 0) {
1602                 free(buf);
1603                 return -1;
1604         }
1605         if (!type)
1606                 type = "blob";
1607         if (write_object)
1608                 ret = write_sha1_file(buf, off, type, sha1);
1609         else {
1610                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1611                 ret = 0;
1612         }
1613         free(buf);
1614         return ret;
1615 }
1616
1617 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1618 {
1619         unsigned long size = st->st_size;
1620         void *buf;
1621         int ret;
1622         unsigned char hdr[50];
1623         int hdrlen;
1624
1625         buf = "";
1626         if (size)
1627                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1628         close(fd);
1629         if (buf == MAP_FAILED)
1630                 return -1;
1631
1632         if (!type)
1633                 type = "blob";
1634         if (write_object)
1635                 ret = write_sha1_file(buf, size, type, sha1);
1636         else {
1637                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1638                 ret = 0;
1639         }
1640         if (size)
1641                 munmap(buf, size);
1642         return ret;
1643 }
1644
1645 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1646 {
1647         int fd;
1648         char *target;
1649
1650         switch (st->st_mode & S_IFMT) {
1651         case S_IFREG:
1652                 fd = open(path, O_RDONLY);
1653                 if (fd < 0)
1654                         return error("open(\"%s\"): %s", path,
1655                                      strerror(errno));
1656                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1657                         return error("%s: failed to insert into database",
1658                                      path);
1659                 break;
1660         case S_IFLNK:
1661                 target = xmalloc(st->st_size+1);
1662                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1663                         char *errstr = strerror(errno);
1664                         free(target);
1665                         return error("readlink(\"%s\"): %s", path,
1666                                      errstr);
1667                 }
1668                 if (!write_object) {
1669                         unsigned char hdr[50];
1670                         int hdrlen;
1671                         write_sha1_file_prepare(target, st->st_size, "blob",
1672                                                 sha1, hdr, &hdrlen);
1673                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1674                         return error("%s: failed to insert into database",
1675                                      path);
1676                 free(target);
1677                 break;
1678         default:
1679                 return error("%s: unsupported file type", path);
1680         }
1681         return 0;
1682 }