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 static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir,
  52         *git_graft_file;
  53 static void setup_git_env(void)
  54 {
  55         git_dir = getenv(GIT_DIR_ENVIRONMENT);
  56         if (!git_dir)
  57                 git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
  58         git_object_dir = getenv(DB_ENVIRONMENT);
  59         if (!git_object_dir) {
  60                 git_object_dir = xmalloc(strlen(git_dir) + 9);
  61                 sprintf(git_object_dir, "%s/objects", git_dir);
  62         }
  63         git_refs_dir = xmalloc(strlen(git_dir) + 6);
  64         sprintf(git_refs_dir, "%s/refs", git_dir);
  65         git_index_file = getenv(INDEX_ENVIRONMENT);
  66         if (!git_index_file) {
  67                 git_index_file = xmalloc(strlen(git_dir) + 7);
  68                 sprintf(git_index_file, "%s/index", git_dir);
  69         }
  70         git_graft_file = getenv(GRAFT_ENVIRONMENT);
  71         if (!git_graft_file)
  72                 git_graft_file = strdup(git_path("info/grafts"));
  73 }
  74
  75 char *get_git_dir(void)
  76 {
  77         if (!git_dir)
  78                 setup_git_env();
  79         return git_dir;
  80 }
  81
  82 char *get_object_directory(void)
  83 {
  84         if (!git_object_dir)
  85                 setup_git_env();
  86         return git_object_dir;
  87 }
  88
  89 char *get_refs_directory(void)
  90 {
  91         if (!git_refs_dir)
  92                 setup_git_env();
  93         return git_refs_dir;
  94 }
  95
  96 char *get_index_file(void)
  97 {
  98         if (!git_index_file)
  99                 setup_git_env();
 100         return git_index_file;
 101 }
 102
 103 char *get_graft_file(void)
 104 {
 105         if (!git_graft_file)
 106                 setup_git_env();
 107         return git_graft_file;
 108 }
 109
 110 int safe_create_leading_directories(char *path)
 111 {
 112         char *pos = path;
 113
 114         while (pos) {
 115                 pos = strchr(pos, '/');
 116                 if (!pos)
 117                         break;
 118                 *pos = 0;
 119                 if (mkdir(path, 0777) < 0)
 120                         if (errno != EEXIST) {
 121                                 *pos = '/';
 122                                 return -1;
 123                         }
 124                 *pos++ = '/';
 125         }
 126         return 0;
 127 }
 128
 129 char * sha1_to_hex(const unsigned char *sha1)
 130 {
 131         static char buffer[50];
 132         static const char hex[] = "0123456789abcdef";
 133         char *buf = buffer;
 134         int i;
 135
 136         for (i = 0; i < 20; i++) {
 137                 unsigned int val = *sha1++;
 138                 *buf++ = hex[val >> 4];
 139                 *buf++ = hex[val & 0xf];
 140         }
 141         return buffer;
 142 }
 143
 144 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 145 {
 146         int i;
 147         for (i = 0; i < 20; i++) {
 148                 static char hex[] = "0123456789abcdef";
 149                 unsigned int val = sha1[i];
 150                 char *pos = pathbuf + i*2 + (i > 0);
 151                 *pos++ = hex[val >> 4];
 152                 *pos = hex[val & 0xf];
 153         }
 154 }
 155
 156 /*
 157  * NOTE! This returns a statically allocated buffer, so you have to be
 158  * careful about using it. Do a "strdup()" if you need to save the
 159  * filename.
 160  *
 161  * Also note that this returns the location for creating.  Reading
 162  * SHA1 file can happen from any alternate directory listed in the
 163  * DB_ENVIRONMENT environment variable if it is not found in
 164  * the primary object database.
 165  */
 166 char *sha1_file_name(const unsigned char *sha1)
 167 {
 168         static char *name, *base;
 169
 170         if (!base) {
 171                 const char *sha1_file_directory = get_object_directory();
 172                 int len = strlen(sha1_file_directory);
 173                 base = xmalloc(len + 60);
 174                 memcpy(base, sha1_file_directory, len);
 175                 memset(base+len, 0, 60);
 176                 base[len] = '/';
 177                 base[len+3] = '/';
 178                 name = base + len + 1;
 179         }
 180         fill_sha1_path(name, sha1);
 181         return base;
 182 }
 183
 184 char *sha1_pack_name(const unsigned char *sha1)
 185 {
 186         static const char hex[] = "0123456789abcdef";
 187         static char *name, *base, *buf;
 188         int i;
 189
 190         if (!base) {
 191                 const char *sha1_file_directory = get_object_directory();
 192                 int len = strlen(sha1_file_directory);
 193                 base = xmalloc(len + 60);
 194                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 195                 name = base + len + 11;
 196         }
 197
 198         buf = name;
 199
 200         for (i = 0; i < 20; i++) {
 201                 unsigned int val = *sha1++;
 202                 *buf++ = hex[val >> 4];
 203                 *buf++ = hex[val & 0xf];
 204         }
 205
 206         return base;
 207 }
 208
 209 char *sha1_pack_index_name(const unsigned char *sha1)
 210 {
 211         static const char hex[] = "0123456789abcdef";
 212         static char *name, *base, *buf;
 213         int i;
 214
 215         if (!base) {
 216                 const char *sha1_file_directory = get_object_directory();
 217                 int len = strlen(sha1_file_directory);
 218                 base = xmalloc(len + 60);
 219                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 220                 name = base + len + 11;
 221         }
 222
 223         buf = name;
 224
 225         for (i = 0; i < 20; i++) {
 226                 unsigned int val = *sha1++;
 227                 *buf++ = hex[val >> 4];
 228                 *buf++ = hex[val & 0xf];
 229         }
 230
 231         return base;
 232 }
 233
 234 struct alternate_object_database *alt_odb_list;
 235 static struct alternate_object_database **alt_odb_tail;
 236
 237 /*
 238  * Prepare alternate object database registry.
 239  *
 240  * The variable alt_odb_list points at the list of struct
 241  * alternate_object_database.  The elements on this list come from
 242  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 243  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 244  * whose contents is exactly in the same format as that environment
 245  * variable.  Its base points at a statically allocated buffer that
 246  * contains "/the/directory/corresponding/to/.git/objects/...", while
 247  * its name points just after the slash at the end of ".git/objects/"
 248  * in the example above, and has enough space to hold 40-byte hex
 249  * SHA1, an extra slash for the first level indirection, and the
 250  * terminating NUL.
 251  */
 252 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 253                                  const char *relative_base)
 254 {
 255         const char *cp, *last;
 256         struct alternate_object_database *ent;
 257         int base_len = -1;
 258
 259         last = alt;
 260         while (last < ep) {
 261                 cp = last;
 262                 if (cp < ep && *cp == '#') {
 263                         while (cp < ep && *cp != sep)
 264                                 cp++;
 265                         last = cp + 1;
 266                         continue;
 267                 }
 268                 for ( ; cp < ep && *cp != sep; cp++)
 269                         ;
 270                 if (last != cp) {
 271                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 272                         int pfxlen = cp - last;
 273                         int entlen = pfxlen + 43;
 274
 275                         if (*last != '/' && relative_base) {
 276                                 /* Relative alt-odb */
 277                                 if (base_len < 0)
 278                                         base_len = strlen(relative_base) + 1;
 279                                 entlen += base_len;
 280                                 pfxlen += base_len;
 281                         }
 282                         ent = xmalloc(sizeof(*ent) + entlen);
 283                         *alt_odb_tail = ent;
 284                         alt_odb_tail = &(ent->next);
 285                         ent->next = NULL;
 286                         if (*last != '/' && relative_base) {
 287                                 memcpy(ent->base, relative_base, base_len - 1);
 288                                 ent->base[base_len - 1] = '/';
 289                                 memcpy(ent->base + base_len,
 290                                        last, cp - last);
 291                         }
 292                         else
 293                                 memcpy(ent->base, last, pfxlen);
 294                         ent->name = ent->base + pfxlen + 1;
 295                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 296                         ent->base[entlen-1] = 0;
 297                 }
 298                 while (cp < ep && *cp == sep)
 299                         cp++;
 300                 last = cp;
 301         }
 302 }
 303
 304 void prepare_alt_odb(void)
 305 {
 306         char path[PATH_MAX];
 307         char *map;
 308         int fd;
 309         struct stat st;
 310         char *alt;
 311
 312         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 313         if (!alt) alt = "";
 314
 315         if (alt_odb_tail)
 316                 return;
 317         alt_odb_tail = &alt_odb_list;
 318         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 319
 320         sprintf(path, "%s/info/alternates", get_object_directory());
 321         fd = open(path, O_RDONLY);
 322         if (fd < 0)
 323                 return;
 324         if (fstat(fd, &st) || (st.st_size == 0)) {
 325                 close(fd);
 326                 return;
 327         }
 328         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 329         close(fd);
 330         if (map == MAP_FAILED)
 331                 return;
 332
 333         link_alt_odb_entries(map, map + st.st_size, '\n',
 334                              get_object_directory());
 335         munmap(map, st.st_size);
 336 }
 337
 338 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 339 {
 340         char *name = sha1_file_name(sha1);
 341         struct alternate_object_database *alt;
 342
 343         if (!stat(name, st))
 344                 return name;
 345         prepare_alt_odb();
 346         for (alt = alt_odb_list; alt; alt = alt->next) {
 347                 name = alt->name;
 348                 fill_sha1_path(name, sha1);
 349                 if (!stat(alt->base, st))
 350                         return alt->base;
 351         }
 352         return NULL;
 353 }
 354
 355 #define PACK_MAX_SZ (1<<26)
 356 static int pack_used_ctr;
 357 static unsigned long pack_mapped;
 358 struct packed_git *packed_git;
 359
 360 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 361                                 void **idx_map_)
 362 {
 363         void *idx_map;
 364         unsigned int *index;
 365         unsigned long idx_size;
 366         int nr, i;
 367         int fd = open(path, O_RDONLY);
 368         struct stat st;
 369         if (fd < 0)
 370                 return -1;
 371         if (fstat(fd, &st)) {
 372                 close(fd);
 373                 return -1;
 374         }
 375         idx_size = st.st_size;
 376         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 377         close(fd);
 378         if (idx_map == MAP_FAILED)
 379                 return -1;
 380
 381         index = idx_map;
 382         *idx_map_ = idx_map;
 383         *idx_size_ = idx_size;
 384
 385         /* check index map */
 386         if (idx_size < 4*256 + 20 + 20)
 387                 return error("index file too small");
 388         nr = 0;
 389         for (i = 0; i < 256; i++) {
 390                 unsigned int n = ntohl(index[i]);
 391                 if (n < nr)
 392                         return error("non-monotonic index");
 393                 nr = n;
 394         }
 395
 396         /*
 397          * Total size:
 398          *  - 256 index entries 4 bytes each
 399          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 400          *  - 20-byte SHA1 of the packfile
 401          *  - 20-byte SHA1 file checksum
 402          */
 403         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 404                 return error("wrong index file size");
 405
 406         return 0;
 407 }
 408
 409 static int unuse_one_packed_git(void)
 410 {
 411         struct packed_git *p, *lru = NULL;
 412
 413         for (p = packed_git; p; p = p->next) {
 414                 if (p->pack_use_cnt || !p->pack_base)
 415                         continue;
 416                 if (!lru || p->pack_last_used < lru->pack_last_used)
 417                         lru = p;
 418         }
 419         if (!lru)
 420                 return 0;
 421         munmap(lru->pack_base, lru->pack_size);
 422         lru->pack_base = NULL;
 423         return 1;
 424 }
 425
 426 void unuse_packed_git(struct packed_git *p)
 427 {
 428         p->pack_use_cnt--;
 429 }
 430
 431 int use_packed_git(struct packed_git *p)
 432 {
 433         if (!p->pack_size) {
 434                 struct stat st;
 435                 // We created the struct before we had the pack
 436                 stat(p->pack_name, &st);
 437                 if (!S_ISREG(st.st_mode))
 438                         die("packfile %s not a regular file", p->pack_name);
 439                 p->pack_size = st.st_size;
 440         }
 441         if (!p->pack_base) {
 442                 int fd;
 443                 struct stat st;
 444                 void *map;
 445
 446                 pack_mapped += p->pack_size;
 447                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 448                         ; /* nothing */
 449                 fd = open(p->pack_name, O_RDONLY);
 450                 if (fd < 0)
 451                         die("packfile %s cannot be opened", p->pack_name);
 452                 if (fstat(fd, &st)) {
 453                         close(fd);
 454                         die("packfile %s cannot be opened", p->pack_name);
 455                 }
 456                 if (st.st_size != p->pack_size)
 457                         die("packfile %s size mismatch.", p->pack_name);
 458                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 459                 close(fd);
 460                 if (map == MAP_FAILED)
 461                         die("packfile %s cannot be mapped.", p->pack_name);
 462                 p->pack_base = map;
 463
 464                 /* Check if the pack file matches with the index file.
 465                  * this is cheap.
 466                  */
 467                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 468                            p->pack_base + p->pack_size - 20, 20)) {
 469
 470                         die("packfile %s does not match index.", p->pack_name);
 471                 }
 472         }
 473         p->pack_last_used = pack_used_ctr++;
 474         p->pack_use_cnt++;
 475         return 0;
 476 }
 477
 478 struct packed_git *add_packed_git(char *path, int path_len)
 479 {
 480         struct stat st;
 481         struct packed_git *p;
 482         unsigned long idx_size;
 483         void *idx_map;
 484
 485         if (check_packed_git_idx(path, &idx_size, &idx_map))
 486                 return NULL;
 487
 488         /* do we have a corresponding .pack file? */
 489         strcpy(path + path_len - 4, ".pack");
 490         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 491                 munmap(idx_map, idx_size);
 492                 return NULL;
 493         }
 494         /* ok, it looks sane as far as we can check without
 495          * actually mapping the pack file.
 496          */
 497         p = xmalloc(sizeof(*p) + path_len + 2);
 498         strcpy(p->pack_name, path);
 499         p->index_size = idx_size;
 500         p->pack_size = st.st_size;
 501         p->index_base = idx_map;
 502         p->next = NULL;
 503         p->pack_base = NULL;
 504         p->pack_last_used = 0;
 505         p->pack_use_cnt = 0;
 506         return p;
 507 }
 508
 509 struct packed_git *parse_pack_index(unsigned char *sha1)
 510 {
 511         char *path = sha1_pack_index_name(sha1);
 512         return parse_pack_index_file(sha1, path);
 513 }
 514
 515 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 516 {
 517         struct packed_git *p;
 518         unsigned long idx_size;
 519         void *idx_map;
 520         char *path;
 521
 522         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 523                 return NULL;
 524
 525         path = sha1_pack_name(sha1);
 526
 527         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 528         strcpy(p->pack_name, path);
 529         p->index_size = idx_size;
 530         p->pack_size = 0;
 531         p->index_base = idx_map;
 532         p->next = NULL;
 533         p->pack_base = NULL;
 534         p->pack_last_used = 0;
 535         p->pack_use_cnt = 0;
 536         memcpy(p->sha1, sha1, 20);
 537         return p;
 538 }
 539
 540 void install_packed_git(struct packed_git *pack)
 541 {
 542         pack->next = packed_git;
 543         packed_git = pack;
 544 }
 545
 546 static void prepare_packed_git_one(char *objdir)
 547 {
 548         char path[PATH_MAX];
 549         int len;
 550         DIR *dir;
 551         struct dirent *de;
 552
 553         sprintf(path, "%s/pack", objdir);
 554         len = strlen(path);
 555         dir = opendir(path);
 556         if (!dir)
 557                 return;
 558         path[len++] = '/';
 559         while ((de = readdir(dir)) != NULL) {
 560                 int namelen = strlen(de->d_name);
 561                 struct packed_git *p;
 562
 563                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 564                         continue;
 565
 566                 /* we have .idx.  Is it a file we can map? */
 567                 strcpy(path + len, de->d_name);
 568                 p = add_packed_git(path, len + namelen);
 569                 if (!p)
 570                         continue;
 571                 p->next = packed_git;
 572                 packed_git = p;
 573         }
 574         closedir(dir);
 575 }
 576
 577 void prepare_packed_git(void)
 578 {
 579         static int run_once = 0;
 580         struct alternate_object_database *alt;
 581
 582         if (run_once)
 583                 return;
 584         prepare_packed_git_one(get_object_directory());
 585         prepare_alt_odb();
 586         for (alt = alt_odb_list; alt; alt = alt->next) {
 587                 alt->name[0] = 0;
 588                 prepare_packed_git_one(alt->base);
 589         }
 590         run_once = 1;
 591 }
 592
 593 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 594 {
 595         char header[100];
 596         unsigned char real_sha1[20];
 597         SHA_CTX c;
 598
 599         SHA1_Init(&c);
 600         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 601         SHA1_Update(&c, map, size);
 602         SHA1_Final(real_sha1, &c);
 603         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 604 }
 605
 606 static void *map_sha1_file_internal(const unsigned char *sha1,
 607                                     unsigned long *size)
 608 {
 609         struct stat st;
 610         void *map;
 611         int fd;
 612         char *filename = find_sha1_file(sha1, &st);
 613
 614         if (!filename) {
 615                 return NULL;
 616         }
 617
 618         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 619         if (fd < 0) {
 620                 /* See if it works without O_NOATIME */
 621                 switch (sha1_file_open_flag) {
 622                 default:
 623                         fd = open(filename, O_RDONLY);
 624                         if (fd >= 0)
 625                                 break;
 626                 /* Fallthrough */
 627                 case 0:
 628                         return NULL;
 629                 }
 630
 631                 /* If it failed once, it will probably fail again.
 632                  * Stop using O_NOATIME
 633                  */
 634                 sha1_file_open_flag = 0;
 635         }
 636         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 637         close(fd);
 638         if (map == MAP_FAILED)
 639                 return NULL;
 640         *size = st.st_size;
 641         return map;
 642 }
 643
 644 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 645 {
 646         /* Get the data stream */
 647         memset(stream, 0, sizeof(*stream));
 648         stream->next_in = map;
 649         stream->avail_in = mapsize;
 650         stream->next_out = buffer;
 651         stream->avail_out = size;
 652
 653         inflateInit(stream);
 654         return inflate(stream, 0);
 655 }
 656
 657 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 658 {
 659         int bytes = strlen(buffer) + 1;
 660         unsigned char *buf = xmalloc(1+size);
 661
 662         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 663         bytes = stream->total_out - bytes;
 664         if (bytes < size) {
 665                 stream->next_out = buf + bytes;
 666                 stream->avail_out = size - bytes;
 667                 while (inflate(stream, Z_FINISH) == Z_OK)
 668                         /* nothing */;
 669         }
 670         buf[size] = 0;
 671         inflateEnd(stream);
 672         return buf;
 673 }
 674
 675 /*
 676  * We used to just use "sscanf()", but that's actually way
 677  * too permissive for what we want to check. So do an anal
 678  * object header parse by hand.
 679  */
 680 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 681 {
 682         int i;
 683         unsigned long size;
 684
 685         /*
 686          * The type can be at most ten bytes (including the
 687          * terminating '\0' that we add), and is followed by
 688          * a space.
 689          */
 690         i = 10;
 691         for (;;) {
 692                 char c = *hdr++;
 693                 if (c == ' ')
 694                         break;
 695                 if (!--i)
 696                         return -1;
 697                 *type++ = c;
 698         }
 699         *type = 0;
 700
 701         /*
 702          * The length must follow immediately, and be in canonical
 703          * decimal format (ie "010" is not valid).
 704          */
 705         size = *hdr++ - '0';
 706         if (size > 9)
 707                 return -1;
 708         if (size) {
 709                 for (;;) {
 710                         unsigned long c = *hdr - '0';
 711                         if (c > 9)
 712                                 break;
 713                         hdr++;
 714                         size = size * 10 + c;
 715                 }
 716         }
 717         *sizep = size;
 718
 719         /*
 720          * The length must be followed by a zero byte
 721          */
 722         return *hdr ? -1 : 0;
 723 }
 724
 725 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 726 {
 727         int ret;
 728         z_stream stream;
 729         char hdr[8192];
 730
 731         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 732         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 733                 return NULL;
 734
 735         return unpack_sha1_rest(&stream, hdr, *size);
 736 }
 737
 738 /* forward declaration for a mutually recursive function */
 739 static int packed_object_info(struct pack_entry *entry,
 740                               char *type, unsigned long *sizep);
 741
 742 static int packed_delta_info(unsigned char *base_sha1,
 743                              unsigned long delta_size,
 744                              unsigned long left,
 745                              char *type,
 746                              unsigned long *sizep,
 747                              struct packed_git *p)
 748 {
 749         struct pack_entry base_ent;
 750
 751         if (left < 20)
 752                 die("truncated pack file");
 753
 754         /* The base entry _must_ be in the same pack */
 755         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 756                 die("failed to find delta-pack base object %s",
 757                     sha1_to_hex(base_sha1));
 758
 759         /* We choose to only get the type of the base object and
 760          * ignore potentially corrupt pack file that expects the delta
 761          * based on a base with a wrong size.  This saves tons of
 762          * inflate() calls.
 763          */
 764
 765         if (packed_object_info(&base_ent, type, NULL))
 766                 die("cannot get info for delta-pack base");
 767
 768         if (sizep) {
 769                 const unsigned char *data;
 770                 unsigned char delta_head[64];
 771                 unsigned long result_size;
 772                 z_stream stream;
 773                 int st;
 774
 775                 memset(&stream, 0, sizeof(stream));
 776
 777                 data = stream.next_in = base_sha1 + 20;
 778                 stream.avail_in = left - 20;
 779                 stream.next_out = delta_head;
 780                 stream.avail_out = sizeof(delta_head);
 781
 782                 inflateInit(&stream);
 783                 st = inflate(&stream, Z_FINISH);
 784                 inflateEnd(&stream);
 785                 if ((st != Z_STREAM_END) &&
 786                     stream.total_out != sizeof(delta_head))
 787                         die("delta data unpack-initial failed");
 788
 789                 /* Examine the initial part of the delta to figure out
 790                  * the result size.
 791                  */
 792                 data = delta_head;
 793                 get_delta_hdr_size(&data); /* ignore base size */
 794
 795                 /* Read the result size */
 796                 result_size = get_delta_hdr_size(&data);
 797                 *sizep = result_size;
 798         }
 799         return 0;
 800 }
 801
 802 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 803         enum object_type *type, unsigned long *sizep)
 804 {
 805         unsigned shift;
 806         unsigned char *pack, c;
 807         unsigned long size;
 808
 809         if (offset >= p->pack_size)
 810                 die("object offset outside of pack file");
 811
 812         pack =  p->pack_base + offset;
 813         c = *pack++;
 814         offset++;
 815         *type = (c >> 4) & 7;
 816         size = c & 15;
 817         shift = 4;
 818         while (c & 0x80) {
 819                 if (offset >= p->pack_size)
 820                         die("object offset outside of pack file");
 821                 c = *pack++;
 822                 offset++;
 823                 size += (c & 0x7f) << shift;
 824                 shift += 7;
 825         }
 826         *sizep = size;
 827         return offset;
 828 }
 829
 830 void packed_object_info_detail(struct pack_entry *e,
 831                                char *type,
 832                                unsigned long *size,
 833                                unsigned long *store_size,
 834                                int *delta_chain_length,
 835                                unsigned char *base_sha1)
 836 {
 837         struct packed_git *p = e->p;
 838         unsigned long offset, left;
 839         unsigned char *pack;
 840         enum object_type kind;
 841
 842         offset = unpack_object_header(p, e->offset, &kind, size);
 843         pack = p->pack_base + offset;
 844         left = p->pack_size - offset;
 845         if (kind != OBJ_DELTA)
 846                 *delta_chain_length = 0;
 847         else {
 848                 int chain_length = 0;
 849                 memcpy(base_sha1, pack, 20);
 850                 do {
 851                         struct pack_entry base_ent;
 852                         unsigned long junk;
 853
 854                         find_pack_entry_one(pack, &base_ent, p);
 855                         offset = unpack_object_header(p, base_ent.offset,
 856                                                       &kind, &junk);
 857                         pack = p->pack_base + offset;
 858                         chain_length++;
 859                 } while (kind == OBJ_DELTA);
 860                 *delta_chain_length = chain_length;
 861         }
 862         switch (kind) {
 863         case OBJ_COMMIT:
 864                 strcpy(type, "commit");
 865                 break;
 866         case OBJ_TREE:
 867                 strcpy(type, "tree");
 868                 break;
 869         case OBJ_BLOB:
 870                 strcpy(type, "blob");
 871                 break;
 872         case OBJ_TAG:
 873                 strcpy(type, "tag");
 874                 break;
 875         default:
 876                 die("corrupted pack file %s containing object of kind %d",
 877                     p->pack_name, kind);
 878         }
 879         *store_size = 0; /* notyet */
 880 }
 881
 882 static int packed_object_info(struct pack_entry *entry,
 883                               char *type, unsigned long *sizep)
 884 {
 885         struct packed_git *p = entry->p;
 886         unsigned long offset, size, left;
 887         unsigned char *pack;
 888         enum object_type kind;
 889         int retval;
 890
 891         if (use_packed_git(p))
 892                 die("cannot map packed file");
 893
 894         offset = unpack_object_header(p, entry->offset, &kind, &size);
 895         pack = p->pack_base + offset;
 896         left = p->pack_size - offset;
 897
 898         switch (kind) {
 899         case OBJ_DELTA:
 900                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 901                 unuse_packed_git(p);
 902                 return retval;
 903         case OBJ_COMMIT:
 904                 strcpy(type, "commit");
 905                 break;
 906         case OBJ_TREE:
 907                 strcpy(type, "tree");
 908                 break;
 909         case OBJ_BLOB:
 910                 strcpy(type, "blob");
 911                 break;
 912         case OBJ_TAG:
 913                 strcpy(type, "tag");
 914                 break;
 915         default:
 916                 die("corrupted pack file %s containing object of kind %d",
 917                     p->pack_name, kind);
 918         }
 919         if (sizep)
 920                 *sizep = size;
 921         unuse_packed_git(p);
 922         return 0;
 923 }
 924
 925 /* forward declaration for a mutually recursive function */
 926 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 927
 928 static void *unpack_delta_entry(unsigned char *base_sha1,
 929                                 unsigned long delta_size,
 930                                 unsigned long left,
 931                                 char *type,
 932                                 unsigned long *sizep,
 933                                 struct packed_git *p)
 934 {
 935         struct pack_entry base_ent;
 936         void *data, *delta_data, *result, *base;
 937         unsigned long data_size, result_size, base_size;
 938         z_stream stream;
 939         int st;
 940
 941         if (left < 20)
 942                 die("truncated pack file");
 943         data = base_sha1 + 20;
 944         data_size = left - 20;
 945         delta_data = xmalloc(delta_size);
 946
 947         memset(&stream, 0, sizeof(stream));
 948
 949         stream.next_in = data;
 950         stream.avail_in = data_size;
 951         stream.next_out = delta_data;
 952         stream.avail_out = delta_size;
 953
 954         inflateInit(&stream);
 955         st = inflate(&stream, Z_FINISH);
 956         inflateEnd(&stream);
 957         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 958                 die("delta data unpack failed");
 959
 960         /* The base entry _must_ be in the same pack */
 961         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 962                 die("failed to find delta-pack base object %s",
 963                     sha1_to_hex(base_sha1));
 964         base = unpack_entry_gently(&base_ent, type, &base_size);
 965         if (!base)
 966                 die("failed to read delta-pack base object %s",
 967                     sha1_to_hex(base_sha1));
 968         result = patch_delta(base, base_size,
 969                              delta_data, delta_size,
 970                              &result_size);
 971         if (!result)
 972                 die("failed to apply delta");
 973         free(delta_data);
 974         free(base);
 975         *sizep = result_size;
 976         return result;
 977 }
 978
 979 static void *unpack_non_delta_entry(unsigned char *data,
 980                                     unsigned long size,
 981                                     unsigned long left)
 982 {
 983         int st;
 984         z_stream stream;
 985         unsigned char *buffer;
 986
 987         buffer = xmalloc(size + 1);
 988         buffer[size] = 0;
 989         memset(&stream, 0, sizeof(stream));
 990         stream.next_in = data;
 991         stream.avail_in = left;
 992         stream.next_out = buffer;
 993         stream.avail_out = size;
 994
 995         inflateInit(&stream);
 996         st = inflate(&stream, Z_FINISH);
 997         inflateEnd(&stream);
 998         if ((st != Z_STREAM_END) || stream.total_out != size) {
 999                 free(buffer);
1000                 return NULL;
1001         }
1002
1003         return buffer;
1004 }
1005
1006 static void *unpack_entry(struct pack_entry *entry,
1007                           char *type, unsigned long *sizep)
1008 {
1009         struct packed_git *p = entry->p;
1010         void *retval;
1011
1012         if (use_packed_git(p))
1013                 die("cannot map packed file");
1014         retval = unpack_entry_gently(entry, type, sizep);
1015         unuse_packed_git(p);
1016         if (!retval)
1017                 die("corrupted pack file %s", p->pack_name);
1018         return retval;
1019 }
1020
1021 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1022 void *unpack_entry_gently(struct pack_entry *entry,
1023                           char *type, unsigned long *sizep)
1024 {
1025         struct packed_git *p = entry->p;
1026         unsigned long offset, size, left;
1027         unsigned char *pack;
1028         enum object_type kind;
1029         void *retval;
1030
1031         offset = unpack_object_header(p, entry->offset, &kind, &size);
1032         pack = p->pack_base + offset;
1033         left = p->pack_size - offset;
1034         switch (kind) {
1035         case OBJ_DELTA:
1036                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1037                 return retval;
1038         case OBJ_COMMIT:
1039                 strcpy(type, "commit");
1040                 break;
1041         case OBJ_TREE:
1042                 strcpy(type, "tree");
1043                 break;
1044         case OBJ_BLOB:
1045                 strcpy(type, "blob");
1046                 break;
1047         case OBJ_TAG:
1048                 strcpy(type, "tag");
1049                 break;
1050         default:
1051                 return NULL;
1052         }
1053         *sizep = size;
1054         retval = unpack_non_delta_entry(pack, size, left);
1055         return retval;
1056 }
1057
1058 int num_packed_objects(const struct packed_git *p)
1059 {
1060         /* See check_packed_git_idx() */
1061         return (p->index_size - 20 - 20 - 4*256) / 24;
1062 }
1063
1064 int nth_packed_object_sha1(const struct packed_git *p, int n,
1065                            unsigned char* sha1)
1066 {
1067         void *index = p->index_base + 256;
1068         if (n < 0 || num_packed_objects(p) <= n)
1069                 return -1;
1070         memcpy(sha1, (index + 24 * n + 4), 20);
1071         return 0;
1072 }
1073
1074 int find_pack_entry_one(const unsigned char *sha1,
1075                         struct pack_entry *e, struct packed_git *p)
1076 {
1077         unsigned int *level1_ofs = p->index_base;
1078         int hi = ntohl(level1_ofs[*sha1]);
1079         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1080         void *index = p->index_base + 256;
1081
1082         do {
1083                 int mi = (lo + hi) / 2;
1084                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1085                 if (!cmp) {
1086                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1087                         memcpy(e->sha1, sha1, 20);
1088                         e->p = p;
1089                         return 1;
1090                 }
1091                 if (cmp > 0)
1092                         hi = mi;
1093                 else
1094                         lo = mi+1;
1095         } while (lo < hi);
1096         return 0;
1097 }
1098
1099 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1100 {
1101         struct packed_git *p;
1102         prepare_packed_git();
1103
1104         for (p = packed_git; p; p = p->next) {
1105                 if (find_pack_entry_one(sha1, e, p))
1106                         return 1;
1107         }
1108         return 0;
1109 }
1110
1111 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1112                                   struct packed_git *packs)
1113 {
1114         struct packed_git *p;
1115         struct pack_entry e;
1116
1117         for (p = packs; p; p = p->next) {
1118                 if (find_pack_entry_one(sha1, &e, p))
1119                         return p;
1120         }
1121         return NULL;
1122
1123 }
1124
1125 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1126 {
1127         int status;
1128         unsigned long mapsize, size;
1129         void *map;
1130         z_stream stream;
1131         char hdr[128];
1132
1133         map = map_sha1_file_internal(sha1, &mapsize);
1134         if (!map) {
1135                 struct pack_entry e;
1136
1137                 if (!find_pack_entry(sha1, &e))
1138                         return error("unable to find %s", sha1_to_hex(sha1));
1139                 return packed_object_info(&e, type, sizep);
1140         }
1141         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1142                 status = error("unable to unpack %s header",
1143                                sha1_to_hex(sha1));
1144         if (parse_sha1_header(hdr, type, &size) < 0)
1145                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1146         else {
1147                 status = 0;
1148                 if (sizep)
1149                         *sizep = size;
1150         }
1151         inflateEnd(&stream);
1152         munmap(map, mapsize);
1153         return status;
1154 }
1155
1156 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1157 {
1158         struct pack_entry e;
1159
1160         if (!find_pack_entry(sha1, &e)) {
1161                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1162                 return NULL;
1163         }
1164         return unpack_entry(&e, type, size);
1165 }
1166
1167 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1168 {
1169         unsigned long mapsize;
1170         void *map, *buf;
1171         struct pack_entry e;
1172
1173         if (find_pack_entry(sha1, &e))
1174                 return read_packed_sha1(sha1, type, size);
1175         map = map_sha1_file_internal(sha1, &mapsize);
1176         if (map) {
1177                 buf = unpack_sha1_file(map, mapsize, type, size);
1178                 munmap(map, mapsize);
1179                 return buf;
1180         }
1181         return NULL;
1182 }
1183
1184 void *read_object_with_reference(const unsigned char *sha1,
1185                                  const char *required_type,
1186                                  unsigned long *size,
1187                                  unsigned char *actual_sha1_return)
1188 {
1189         char type[20];
1190         void *buffer;
1191         unsigned long isize;
1192         unsigned char actual_sha1[20];
1193
1194         memcpy(actual_sha1, sha1, 20);
1195         while (1) {
1196                 int ref_length = -1;
1197                 const char *ref_type = NULL;
1198
1199                 buffer = read_sha1_file(actual_sha1, type, &isize);
1200                 if (!buffer)
1201                         return NULL;
1202                 if (!strcmp(type, required_type)) {
1203                         *size = isize;
1204                         if (actual_sha1_return)
1205                                 memcpy(actual_sha1_return, actual_sha1, 20);
1206                         return buffer;
1207                 }
1208                 /* Handle references */
1209                 else if (!strcmp(type, "commit"))
1210                         ref_type = "tree ";
1211                 else if (!strcmp(type, "tag"))
1212                         ref_type = "object ";
1213                 else {
1214                         free(buffer);
1215                         return NULL;
1216                 }
1217                 ref_length = strlen(ref_type);
1218
1219                 if (memcmp(buffer, ref_type, ref_length) ||
1220                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1221                         free(buffer);
1222                         return NULL;
1223                 }
1224                 free(buffer);
1225                 /* Now we have the ID of the referred-to object in
1226                  * actual_sha1.  Check again. */
1227         }
1228 }
1229
1230 char *write_sha1_file_prepare(void *buf,
1231                               unsigned long len,
1232                               const char *type,
1233                               unsigned char *sha1,
1234                               unsigned char *hdr,
1235                               int *hdrlen)
1236 {
1237         SHA_CTX c;
1238
1239         /* Generate the header */
1240         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1241
1242         /* Sha1.. */
1243         SHA1_Init(&c);
1244         SHA1_Update(&c, hdr, *hdrlen);
1245         SHA1_Update(&c, buf, len);
1246         SHA1_Final(sha1, &c);
1247
1248         return sha1_file_name(sha1);
1249 }
1250
1251 /*
1252  * Link the tempfile to the final place, possibly creating the
1253  * last directory level as you do so.
1254  *
1255  * Returns the errno on failure, 0 on success.
1256  */
1257 static int link_temp_to_file(const char *tmpfile, char *filename)
1258 {
1259         int ret;
1260
1261         if (!link(tmpfile, filename))
1262                 return 0;
1263
1264         /*
1265          * Try to mkdir the last path component if that failed
1266          * with an ENOENT.
1267          *
1268          * Re-try the "link()" regardless of whether the mkdir
1269          * succeeds, since a race might mean that somebody
1270          * else succeeded.
1271          */
1272         ret = errno;
1273         if (ret == ENOENT) {
1274                 char *dir = strrchr(filename, '/');
1275                 if (dir) {
1276                         *dir = 0;
1277                         mkdir(filename, 0777);
1278                         *dir = '/';
1279                         if (!link(tmpfile, filename))
1280                                 return 0;
1281                         ret = errno;
1282                 }
1283         }
1284         return ret;
1285 }
1286
1287 /*
1288  * Move the just written object into its final resting place
1289  */
1290 int move_temp_to_file(const char *tmpfile, char *filename)
1291 {
1292         int ret = link_temp_to_file(tmpfile, filename);
1293         if (ret) {
1294                 /*
1295                  * Coda hack - coda doesn't like cross-directory links,
1296                  * so we fall back to a rename, which will mean that it
1297                  * won't be able to check collisions, but that's not a
1298                  * big deal.
1299                  *
1300                  * When this succeeds, we just return 0. We have nothing
1301                  * left to unlink.
1302                  */
1303                 if (ret == EXDEV && !rename(tmpfile, filename))
1304                         return 0;
1305         }
1306         unlink(tmpfile);
1307         if (ret) {
1308                 if (ret != EEXIST) {
1309                         fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
1310                         return -1;
1311                 }
1312                 /* FIXME!!! Collision check here ? */
1313         }
1314
1315         return 0;
1316 }
1317
1318 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1319 {
1320         int size;
1321         unsigned char *compressed;
1322         z_stream stream;
1323         unsigned char sha1[20];
1324         char *filename;
1325         static char tmpfile[PATH_MAX];
1326         unsigned char hdr[50];
1327         int fd, hdrlen;
1328
1329         /* Normally if we have it in the pack then we do not bother writing
1330          * it out into .git/objects/??/?{38} file.
1331          */
1332         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1333         if (returnsha1)
1334                 memcpy(returnsha1, sha1, 20);
1335         if (has_sha1_file(sha1))
1336                 return 0;
1337         fd = open(filename, O_RDONLY);
1338         if (fd >= 0) {
1339                 /*
1340                  * FIXME!!! We might do collision checking here, but we'd
1341                  * need to uncompress the old file and check it. Later.
1342                  */
1343                 close(fd);
1344                 return 0;
1345         }
1346
1347         if (errno != ENOENT) {
1348                 fprintf(stderr, "sha1 file %s: %s", filename, strerror(errno));
1349                 return -1;
1350         }
1351
1352         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1353
1354         fd = mkstemp(tmpfile);
1355         if (fd < 0) {
1356                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s", tmpfile, strerror(errno));
1357                 return -1;
1358         }
1359
1360         /* Set it up */
1361         memset(&stream, 0, sizeof(stream));
1362         deflateInit(&stream, Z_BEST_COMPRESSION);
1363         size = deflateBound(&stream, len+hdrlen);
1364         compressed = xmalloc(size);
1365
1366         /* Compress it */
1367         stream.next_out = compressed;
1368         stream.avail_out = size;
1369
1370         /* First header.. */
1371         stream.next_in = hdr;
1372         stream.avail_in = hdrlen;
1373         while (deflate(&stream, 0) == Z_OK)
1374                 /* nothing */;
1375
1376         /* Then the data itself.. */
1377         stream.next_in = buf;
1378         stream.avail_in = len;
1379         while (deflate(&stream, Z_FINISH) == Z_OK)
1380                 /* nothing */;
1381         deflateEnd(&stream);
1382         size = stream.total_out;
1383
1384         if (write(fd, compressed, size) != size)
1385                 die("unable to write file");
1386         fchmod(fd, 0444);
1387         close(fd);
1388         free(compressed);
1389
1390         return move_temp_to_file(tmpfile, filename);
1391 }
1392
1393 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1394 {
1395         ssize_t size;
1396         unsigned long objsize;
1397         int posn = 0;
1398         void *map = map_sha1_file_internal(sha1, &objsize);
1399         void *buf = map;
1400         void *temp_obj = NULL;
1401         z_stream stream;
1402
1403         if (!buf) {
1404                 unsigned char *unpacked;
1405                 unsigned long len;
1406                 char type[20];
1407                 char hdr[50];
1408                 int hdrlen;
1409                 // need to unpack and recompress it by itself
1410                 unpacked = read_packed_sha1(sha1, type, &len);
1411
1412                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1413
1414                 /* Set it up */
1415                 memset(&stream, 0, sizeof(stream));
1416                 deflateInit(&stream, Z_BEST_COMPRESSION);
1417                 size = deflateBound(&stream, len + hdrlen);
1418                 temp_obj = buf = xmalloc(size);
1419
1420                 /* Compress it */
1421                 stream.next_out = buf;
1422                 stream.avail_out = size;
1423
1424                 /* First header.. */
1425                 stream.next_in = (void *)hdr;
1426                 stream.avail_in = hdrlen;
1427                 while (deflate(&stream, 0) == Z_OK)
1428                         /* nothing */;
1429
1430                 /* Then the data itself.. */
1431                 stream.next_in = unpacked;
1432                 stream.avail_in = len;
1433                 while (deflate(&stream, Z_FINISH) == Z_OK)
1434                         /* nothing */;
1435                 deflateEnd(&stream);
1436                 free(unpacked);
1437
1438                 objsize = stream.total_out;
1439         }
1440
1441         do {
1442                 size = write(fd, buf + posn, objsize - posn);
1443                 if (size <= 0) {
1444                         if (!size) {
1445                                 fprintf(stderr, "write closed");
1446                         } else {
1447                                 perror("write ");
1448                         }
1449                         return -1;
1450                 }
1451                 posn += size;
1452         } while (posn < objsize);
1453
1454         if (map)
1455                 munmap(map, objsize);
1456         if (temp_obj)
1457                 free(temp_obj);
1458
1459         return 0;
1460 }
1461
1462 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1463                        size_t bufsize, size_t *bufposn)
1464 {
1465         char tmpfile[PATH_MAX];
1466         int local;
1467         z_stream stream;
1468         unsigned char real_sha1[20];
1469         unsigned char discard[4096];
1470         int ret;
1471         SHA_CTX c;
1472
1473         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1474
1475         local = mkstemp(tmpfile);
1476         if (local < 0)
1477                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1478
1479         memset(&stream, 0, sizeof(stream));
1480
1481         inflateInit(&stream);
1482
1483         SHA1_Init(&c);
1484
1485         do {
1486                 ssize_t size;
1487                 if (*bufposn) {
1488                         stream.avail_in = *bufposn;
1489                         stream.next_in = (unsigned char *) buffer;
1490                         do {
1491                                 stream.next_out = discard;
1492                                 stream.avail_out = sizeof(discard);
1493                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1494                                 SHA1_Update(&c, discard, sizeof(discard) -
1495                                             stream.avail_out);
1496                         } while (stream.avail_in && ret == Z_OK);
1497                         write(local, buffer, *bufposn - stream.avail_in);
1498                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1499                                 stream.avail_in);
1500                         *bufposn = stream.avail_in;
1501                         if (ret != Z_OK)
1502                                 break;
1503                 }
1504                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1505                 if (size <= 0) {
1506                         close(local);
1507                         unlink(tmpfile);
1508                         if (!size)
1509                                 return error("Connection closed?");
1510                         perror("Reading from connection");
1511                         return -1;
1512                 }
1513                 *bufposn += size;
1514         } while (1);
1515         inflateEnd(&stream);
1516
1517         close(local);
1518         SHA1_Final(real_sha1, &c);
1519         if (ret != Z_STREAM_END) {
1520                 unlink(tmpfile);
1521                 return error("File %s corrupted", sha1_to_hex(sha1));
1522         }
1523         if (memcmp(sha1, real_sha1, 20)) {
1524                 unlink(tmpfile);
1525                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1526         }
1527
1528         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1529 }
1530
1531 int has_pack_index(const unsigned char *sha1)
1532 {
1533         struct stat st;
1534         if (stat(sha1_pack_index_name(sha1), &st))
1535                 return 0;
1536         return 1;
1537 }
1538
1539 int has_pack_file(const unsigned char *sha1)
1540 {
1541         struct stat st;
1542         if (stat(sha1_pack_name(sha1), &st))
1543                 return 0;
1544         return 1;
1545 }
1546
1547 int has_sha1_pack(const unsigned char *sha1)
1548 {
1549         struct pack_entry e;
1550         return find_pack_entry(sha1, &e);
1551 }
1552
1553 int has_sha1_file(const unsigned char *sha1)
1554 {
1555         struct stat st;
1556         struct pack_entry e;
1557
1558         if (find_pack_entry(sha1, &e))
1559                 return 1;
1560         return find_sha1_file(sha1, &st) ? 1 : 0;
1561 }
1562
1563 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1564 {
1565         unsigned long size = st->st_size;
1566         void *buf;
1567         int ret;
1568         unsigned char hdr[50];
1569         int hdrlen;
1570
1571         buf = "";
1572         if (size)
1573                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1574         close(fd);
1575         if (buf == MAP_FAILED)
1576                 return -1;
1577
1578         if (!type)
1579                 type = "blob";
1580         if (write_object)
1581                 ret = write_sha1_file(buf, size, type, sha1);
1582         else {
1583                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1584                 ret = 0;
1585         }
1586         if (size)
1587                 munmap(buf, size);
1588         return ret;
1589 }
1590
1591 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1592 {
1593         int fd;
1594         char *target;
1595
1596         switch (st->st_mode & S_IFMT) {
1597         case S_IFREG:
1598                 fd = open(path, O_RDONLY);
1599                 if (fd < 0)
1600                         return error("open(\"%s\"): %s", path,
1601                                      strerror(errno));
1602                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1603                         return error("%s: failed to insert into database",
1604                                      path);
1605                 break;
1606         case S_IFLNK:
1607                 target = xmalloc(st->st_size+1);
1608                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1609                         char *errstr = strerror(errno);
1610                         free(target);
1611                         return error("readlink(\"%s\"): %s", path,
1612                                      errstr);
1613                 }
1614                 if (!write_object) {
1615                         unsigned char hdr[50];
1616                         int hdrlen;
1617                         write_sha1_file_prepare(target, st->st_size, "blob",
1618                                                 sha1, hdr, &hdrlen);
1619                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1620                         return error("%s: failed to insert into database",
1621                                      path);
1622                 free(target);
1623                 break;
1624         default:
1625                 return error("%s: unsupported file type", path);
1626         }
1627         return 0;
1628 }