sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include <sys/types.h>
  10 #include <dirent.h>
  11 #include "cache.h"
  12 #include "delta.h"
  13 #include "pack.h"
  14
  15 #ifndef O_NOATIME
  16 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  17 #define O_NOATIME 01000000
  18 #else
  19 #define O_NOATIME 0
  20 #endif
  21 #endif
  22
  23 const unsigned char null_sha1[20] = { 0, };
  24
  25 static unsigned int sha1_file_open_flag = O_NOATIME;
  26
  27 static unsigned hexval(char c)
  28 {
  29         if (c >= '0' && c <= '9')
  30                 return c - '0';
  31         if (c >= 'a' && c <= 'f')
  32                 return c - 'a' + 10;
  33         if (c >= 'A' && c <= 'F')
  34                 return c - 'A' + 10;
  35         return ~0;
  36 }
  37
  38 int get_sha1_hex(const char *hex, unsigned char *sha1)
  39 {
  40         int i;
  41         for (i = 0; i < 20; i++) {
  42                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  43                 if (val & ~0xff)
  44                         return -1;
  45                 *sha1++ = val;
  46                 hex += 2;
  47         }
  48         return 0;
  49 }
  50
  51 int safe_create_leading_directories(char *path)
  52 {
  53         char *pos = path;
  54         if (*pos == '/')
  55                 pos++;
  56
  57         while (pos) {
  58                 pos = strchr(pos, '/');
  59                 if (!pos)
  60                         break;
  61                 *pos = 0;
  62                 if (mkdir(path, 0777) < 0)
  63                         if (errno != EEXIST) {
  64                                 *pos = '/';
  65                                 return -1;
  66                         }
  67                 *pos++ = '/';
  68         }
  69         return 0;
  70 }
  71
  72 char * sha1_to_hex(const unsigned char *sha1)
  73 {
  74         static char buffer[50];
  75         static const char hex[] = "0123456789abcdef";
  76         char *buf = buffer;
  77         int i;
  78
  79         for (i = 0; i < 20; i++) {
  80                 unsigned int val = *sha1++;
  81                 *buf++ = hex[val >> 4];
  82                 *buf++ = hex[val & 0xf];
  83         }
  84         *buf = '\0';
  85
  86         return buffer;
  87 }
  88
  89 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
  90 {
  91         int i;
  92         for (i = 0; i < 20; i++) {
  93                 static char hex[] = "0123456789abcdef";
  94                 unsigned int val = sha1[i];
  95                 char *pos = pathbuf + i*2 + (i > 0);
  96                 *pos++ = hex[val >> 4];
  97                 *pos = hex[val & 0xf];
  98         }
  99 }
 100
 101 /*
 102  * NOTE! This returns a statically allocated buffer, so you have to be
 103  * careful about using it. Do a "strdup()" if you need to save the
 104  * filename.
 105  *
 106  * Also note that this returns the location for creating.  Reading
 107  * SHA1 file can happen from any alternate directory listed in the
 108  * DB_ENVIRONMENT environment variable if it is not found in
 109  * the primary object database.
 110  */
 111 char *sha1_file_name(const unsigned char *sha1)
 112 {
 113         static char *name, *base;
 114
 115         if (!base) {
 116                 const char *sha1_file_directory = get_object_directory();
 117                 int len = strlen(sha1_file_directory);
 118                 base = xmalloc(len + 60);
 119                 memcpy(base, sha1_file_directory, len);
 120                 memset(base+len, 0, 60);
 121                 base[len] = '/';
 122                 base[len+3] = '/';
 123                 name = base + len + 1;
 124         }
 125         fill_sha1_path(name, sha1);
 126         return base;
 127 }
 128
 129 char *sha1_pack_name(const unsigned char *sha1)
 130 {
 131         static const char hex[] = "0123456789abcdef";
 132         static char *name, *base, *buf;
 133         int i;
 134
 135         if (!base) {
 136                 const char *sha1_file_directory = get_object_directory();
 137                 int len = strlen(sha1_file_directory);
 138                 base = xmalloc(len + 60);
 139                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 140                 name = base + len + 11;
 141         }
 142
 143         buf = name;
 144
 145         for (i = 0; i < 20; i++) {
 146                 unsigned int val = *sha1++;
 147                 *buf++ = hex[val >> 4];
 148                 *buf++ = hex[val & 0xf];
 149         }
 150
 151         return base;
 152 }
 153
 154 char *sha1_pack_index_name(const unsigned char *sha1)
 155 {
 156         static const char hex[] = "0123456789abcdef";
 157         static char *name, *base, *buf;
 158         int i;
 159
 160         if (!base) {
 161                 const char *sha1_file_directory = get_object_directory();
 162                 int len = strlen(sha1_file_directory);
 163                 base = xmalloc(len + 60);
 164                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 165                 name = base + len + 11;
 166         }
 167
 168         buf = name;
 169
 170         for (i = 0; i < 20; i++) {
 171                 unsigned int val = *sha1++;
 172                 *buf++ = hex[val >> 4];
 173                 *buf++ = hex[val & 0xf];
 174         }
 175
 176         return base;
 177 }
 178
 179 struct alternate_object_database *alt_odb_list;
 180 static struct alternate_object_database **alt_odb_tail;
 181
 182 /*
 183  * Prepare alternate object database registry.
 184  *
 185  * The variable alt_odb_list points at the list of struct
 186  * alternate_object_database.  The elements on this list come from
 187  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 188  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 189  * whose contents is similar to that environment variable but can be
 190  * LF separated.  Its base points at a statically allocated buffer that
 191  * contains "/the/directory/corresponding/to/.git/objects/...", while
 192  * its name points just after the slash at the end of ".git/objects/"
 193  * in the example above, and has enough space to hold 40-byte hex
 194  * SHA1, an extra slash for the first level indirection, and the
 195  * terminating NUL.
 196  */
 197 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 198                                  const char *relative_base)
 199 {
 200         const char *cp, *last;
 201         struct alternate_object_database *ent;
 202         const char *objdir = get_object_directory();
 203         int base_len = -1;
 204
 205         last = alt;
 206         while (last < ep) {
 207                 cp = last;
 208                 if (cp < ep && *cp == '#') {
 209                         while (cp < ep && *cp != sep)
 210                                 cp++;
 211                         last = cp + 1;
 212                         continue;
 213                 }
 214                 for ( ; cp < ep && *cp != sep; cp++)
 215                         ;
 216                 if (last != cp) {
 217                         struct alternate_object_database *alt;
 218                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 219                         int pfxlen = cp - last;
 220                         int entlen = pfxlen + 43;
 221
 222                         if (*last != '/' && relative_base) {
 223                                 /* Relative alt-odb */
 224                                 if (base_len < 0)
 225                                         base_len = strlen(relative_base) + 1;
 226                                 entlen += base_len;
 227                                 pfxlen += base_len;
 228                         }
 229                         ent = xmalloc(sizeof(*ent) + entlen);
 230
 231                         if (*last != '/' && relative_base) {
 232                                 memcpy(ent->base, relative_base, base_len - 1);
 233                                 ent->base[base_len - 1] = '/';
 234                                 memcpy(ent->base + base_len,
 235                                        last, cp - last);
 236                         }
 237                         else
 238                                 memcpy(ent->base, last, pfxlen);
 239                         ent->name = ent->base + pfxlen + 1;
 240                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 241                         ent->base[entlen-1] = 0;
 242
 243                         /* Prevent the common mistake of listing the same
 244                          * thing twice, or object directory itself.
 245                          */
 246                         for (alt = alt_odb_list; alt; alt = alt->next)
 247                                 if (!memcmp(ent->base, alt->base, pfxlen))
 248                                         goto bad;
 249                         if (!memcmp(ent->base, objdir, pfxlen)) {
 250                         bad:
 251                                 free(ent);
 252                         }
 253                         else {
 254                                 *alt_odb_tail = ent;
 255                                 alt_odb_tail = &(ent->next);
 256                                 ent->next = NULL;
 257                         }
 258                 }
 259                 while (cp < ep && *cp == sep)
 260                         cp++;
 261                 last = cp;
 262         }
 263 }
 264
 265 void prepare_alt_odb(void)
 266 {
 267         char path[PATH_MAX];
 268         char *map;
 269         int fd;
 270         struct stat st;
 271         char *alt;
 272
 273         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 274         if (!alt) alt = "";
 275
 276         if (alt_odb_tail)
 277                 return;
 278         alt_odb_tail = &alt_odb_list;
 279         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 280
 281         sprintf(path, "%s/info/alternates", get_object_directory());
 282         fd = open(path, O_RDONLY);
 283         if (fd < 0)
 284                 return;
 285         if (fstat(fd, &st) || (st.st_size == 0)) {
 286                 close(fd);
 287                 return;
 288         }
 289         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 290         close(fd);
 291         if (map == MAP_FAILED)
 292                 return;
 293
 294         link_alt_odb_entries(map, map + st.st_size, '\n',
 295                              get_object_directory());
 296         munmap(map, st.st_size);
 297 }
 298
 299 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 300 {
 301         char *name = sha1_file_name(sha1);
 302         struct alternate_object_database *alt;
 303
 304         if (!stat(name, st))
 305                 return name;
 306         prepare_alt_odb();
 307         for (alt = alt_odb_list; alt; alt = alt->next) {
 308                 name = alt->name;
 309                 fill_sha1_path(name, sha1);
 310                 if (!stat(alt->base, st))
 311                         return alt->base;
 312         }
 313         return NULL;
 314 }
 315
 316 #define PACK_MAX_SZ (1<<26)
 317 static int pack_used_ctr;
 318 static unsigned long pack_mapped;
 319 struct packed_git *packed_git;
 320
 321 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 322                                 void **idx_map_)
 323 {
 324         SHA_CTX ctx;
 325         unsigned char sha1[20];
 326         void *idx_map;
 327         unsigned int *index;
 328         unsigned long idx_size;
 329         int nr, i;
 330         int fd;
 331         struct stat st;
 332
 333         fd = open(path, O_RDONLY);
 334         if (fd < 0)
 335                 return -1;
 336         if (fstat(fd, &st)) {
 337                 close(fd);
 338                 return -1;
 339         }
 340         idx_size = st.st_size;
 341         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 342         close(fd);
 343         if (idx_map == MAP_FAILED)
 344                 return -1;
 345
 346         index = idx_map;
 347         *idx_map_ = idx_map;
 348         *idx_size_ = idx_size;
 349
 350         /* check index map */
 351         if (idx_size < 4*256 + 20 + 20)
 352                 return error("index file too small");
 353         nr = 0;
 354         for (i = 0; i < 256; i++) {
 355                 unsigned int n = ntohl(index[i]);
 356                 if (n < nr)
 357                         return error("non-monotonic index");
 358                 nr = n;
 359         }
 360
 361         /*
 362          * Total size:
 363          *  - 256 index entries 4 bytes each
 364          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 365          *  - 20-byte SHA1 of the packfile
 366          *  - 20-byte SHA1 file checksum
 367          */
 368         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 369                 return error("wrong index file size");
 370
 371         /*
 372          * File checksum.
 373          */
 374         SHA1_Init(&ctx);
 375         SHA1_Update(&ctx, idx_map, idx_size-20);
 376         SHA1_Final(sha1, &ctx);
 377
 378         if (memcmp(sha1, idx_map + idx_size - 20, 20))
 379                 return error("index checksum mismatch");
 380
 381         return 0;
 382 }
 383
 384 static int unuse_one_packed_git(void)
 385 {
 386         struct packed_git *p, *lru = NULL;
 387
 388         for (p = packed_git; p; p = p->next) {
 389                 if (p->pack_use_cnt || !p->pack_base)
 390                         continue;
 391                 if (!lru || p->pack_last_used < lru->pack_last_used)
 392                         lru = p;
 393         }
 394         if (!lru)
 395                 return 0;
 396         munmap(lru->pack_base, lru->pack_size);
 397         lru->pack_base = NULL;
 398         return 1;
 399 }
 400
 401 void unuse_packed_git(struct packed_git *p)
 402 {
 403         p->pack_use_cnt--;
 404 }
 405
 406 int use_packed_git(struct packed_git *p)
 407 {
 408         if (!p->pack_size) {
 409                 struct stat st;
 410                 // We created the struct before we had the pack
 411                 stat(p->pack_name, &st);
 412                 if (!S_ISREG(st.st_mode))
 413                         die("packfile %s not a regular file", p->pack_name);
 414                 p->pack_size = st.st_size;
 415         }
 416         if (!p->pack_base) {
 417                 int fd;
 418                 struct stat st;
 419                 void *map;
 420
 421                 pack_mapped += p->pack_size;
 422                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 423                         ; /* nothing */
 424                 fd = open(p->pack_name, O_RDONLY);
 425                 if (fd < 0)
 426                         die("packfile %s cannot be opened", p->pack_name);
 427                 if (fstat(fd, &st)) {
 428                         close(fd);
 429                         die("packfile %s cannot be opened", p->pack_name);
 430                 }
 431                 if (st.st_size != p->pack_size)
 432                         die("packfile %s size mismatch.", p->pack_name);
 433                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 434                 close(fd);
 435                 if (map == MAP_FAILED)
 436                         die("packfile %s cannot be mapped.", p->pack_name);
 437                 p->pack_base = map;
 438
 439                 /* Check if the pack file matches with the index file.
 440                  * this is cheap.
 441                  */
 442                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 443                            p->pack_base + p->pack_size - 20, 20)) {
 444
 445                         die("packfile %s does not match index.", p->pack_name);
 446                 }
 447         }
 448         p->pack_last_used = pack_used_ctr++;
 449         p->pack_use_cnt++;
 450         return 0;
 451 }
 452
 453 struct packed_git *add_packed_git(char *path, int path_len, int local)
 454 {
 455         struct stat st;
 456         struct packed_git *p;
 457         unsigned long idx_size;
 458         void *idx_map;
 459         unsigned char sha1[20];
 460
 461         if (check_packed_git_idx(path, &idx_size, &idx_map))
 462                 return NULL;
 463
 464         /* do we have a corresponding .pack file? */
 465         strcpy(path + path_len - 4, ".pack");
 466         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 467                 munmap(idx_map, idx_size);
 468                 return NULL;
 469         }
 470         /* ok, it looks sane as far as we can check without
 471          * actually mapping the pack file.
 472          */
 473         p = xmalloc(sizeof(*p) + path_len + 2);
 474         strcpy(p->pack_name, path);
 475         p->index_size = idx_size;
 476         p->pack_size = st.st_size;
 477         p->index_base = idx_map;
 478         p->next = NULL;
 479         p->pack_base = NULL;
 480         p->pack_last_used = 0;
 481         p->pack_use_cnt = 0;
 482         p->pack_local = local;
 483         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 484                 memcpy(p->sha1, sha1, 20);
 485         return p;
 486 }
 487
 488 struct packed_git *parse_pack_index(unsigned char *sha1)
 489 {
 490         char *path = sha1_pack_index_name(sha1);
 491         return parse_pack_index_file(sha1, path);
 492 }
 493
 494 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 495 {
 496         struct packed_git *p;
 497         unsigned long idx_size;
 498         void *idx_map;
 499         char *path;
 500
 501         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 502                 return NULL;
 503
 504         path = sha1_pack_name(sha1);
 505
 506         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 507         strcpy(p->pack_name, path);
 508         p->index_size = idx_size;
 509         p->pack_size = 0;
 510         p->index_base = idx_map;
 511         p->next = NULL;
 512         p->pack_base = NULL;
 513         p->pack_last_used = 0;
 514         p->pack_use_cnt = 0;
 515         memcpy(p->sha1, sha1, 20);
 516         return p;
 517 }
 518
 519 void install_packed_git(struct packed_git *pack)
 520 {
 521         pack->next = packed_git;
 522         packed_git = pack;
 523 }
 524
 525 static void prepare_packed_git_one(char *objdir, int local)
 526 {
 527         char path[PATH_MAX];
 528         int len;
 529         DIR *dir;
 530         struct dirent *de;
 531
 532         sprintf(path, "%s/pack", objdir);
 533         len = strlen(path);
 534         dir = opendir(path);
 535         if (!dir)
 536                 return;
 537         path[len++] = '/';
 538         while ((de = readdir(dir)) != NULL) {
 539                 int namelen = strlen(de->d_name);
 540                 struct packed_git *p;
 541
 542                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 543                         continue;
 544
 545                 /* we have .idx.  Is it a file we can map? */
 546                 strcpy(path + len, de->d_name);
 547                 p = add_packed_git(path, len + namelen, local);
 548                 if (!p)
 549                         continue;
 550                 p->next = packed_git;
 551                 packed_git = p;
 552         }
 553         closedir(dir);
 554 }
 555
 556 void prepare_packed_git(void)
 557 {
 558         static int run_once = 0;
 559         struct alternate_object_database *alt;
 560
 561         if (run_once)
 562                 return;
 563         prepare_packed_git_one(get_object_directory(), 1);
 564         prepare_alt_odb();
 565         for (alt = alt_odb_list; alt; alt = alt->next) {
 566                 alt->name[-1] = 0;
 567                 prepare_packed_git_one(alt->base, 0);
 568                 alt->name[-1] = '/';
 569         }
 570         run_once = 1;
 571 }
 572
 573 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 574 {
 575         char header[100];
 576         unsigned char real_sha1[20];
 577         SHA_CTX c;
 578
 579         SHA1_Init(&c);
 580         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 581         SHA1_Update(&c, map, size);
 582         SHA1_Final(real_sha1, &c);
 583         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 584 }
 585
 586 static void *map_sha1_file_internal(const unsigned char *sha1,
 587                                     unsigned long *size)
 588 {
 589         struct stat st;
 590         void *map;
 591         int fd;
 592         char *filename = find_sha1_file(sha1, &st);
 593
 594         if (!filename) {
 595                 return NULL;
 596         }
 597
 598         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 599         if (fd < 0) {
 600                 /* See if it works without O_NOATIME */
 601                 switch (sha1_file_open_flag) {
 602                 default:
 603                         fd = open(filename, O_RDONLY);
 604                         if (fd >= 0)
 605                                 break;
 606                 /* Fallthrough */
 607                 case 0:
 608                         return NULL;
 609                 }
 610
 611                 /* If it failed once, it will probably fail again.
 612                  * Stop using O_NOATIME
 613                  */
 614                 sha1_file_open_flag = 0;
 615         }
 616         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 617         close(fd);
 618         if (map == MAP_FAILED)
 619                 return NULL;
 620         *size = st.st_size;
 621         return map;
 622 }
 623
 624 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 625 {
 626         /* Get the data stream */
 627         memset(stream, 0, sizeof(*stream));
 628         stream->next_in = map;
 629         stream->avail_in = mapsize;
 630         stream->next_out = buffer;
 631         stream->avail_out = size;
 632
 633         inflateInit(stream);
 634         return inflate(stream, 0);
 635 }
 636
 637 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 638 {
 639         int bytes = strlen(buffer) + 1;
 640         unsigned char *buf = xmalloc(1+size);
 641
 642         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 643         bytes = stream->total_out - bytes;
 644         if (bytes < size) {
 645                 stream->next_out = buf + bytes;
 646                 stream->avail_out = size - bytes;
 647                 while (inflate(stream, Z_FINISH) == Z_OK)
 648                         /* nothing */;
 649         }
 650         buf[size] = 0;
 651         inflateEnd(stream);
 652         return buf;
 653 }
 654
 655 /*
 656  * We used to just use "sscanf()", but that's actually way
 657  * too permissive for what we want to check. So do an anal
 658  * object header parse by hand.
 659  */
 660 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 661 {
 662         int i;
 663         unsigned long size;
 664
 665         /*
 666          * The type can be at most ten bytes (including the
 667          * terminating '\0' that we add), and is followed by
 668          * a space.
 669          */
 670         i = 10;
 671         for (;;) {
 672                 char c = *hdr++;
 673                 if (c == ' ')
 674                         break;
 675                 if (!--i)
 676                         return -1;
 677                 *type++ = c;
 678         }
 679         *type = 0;
 680
 681         /*
 682          * The length must follow immediately, and be in canonical
 683          * decimal format (ie "010" is not valid).
 684          */
 685         size = *hdr++ - '0';
 686         if (size > 9)
 687                 return -1;
 688         if (size) {
 689                 for (;;) {
 690                         unsigned long c = *hdr - '0';
 691                         if (c > 9)
 692                                 break;
 693                         hdr++;
 694                         size = size * 10 + c;
 695                 }
 696         }
 697         *sizep = size;
 698
 699         /*
 700          * The length must be followed by a zero byte
 701          */
 702         return *hdr ? -1 : 0;
 703 }
 704
 705 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 706 {
 707         int ret;
 708         z_stream stream;
 709         char hdr[8192];
 710
 711         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 712         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 713                 return NULL;
 714
 715         return unpack_sha1_rest(&stream, hdr, *size);
 716 }
 717
 718 /* forward declaration for a mutually recursive function */
 719 static int packed_object_info(struct pack_entry *entry,
 720                               char *type, unsigned long *sizep);
 721
 722 static int packed_delta_info(unsigned char *base_sha1,
 723                              unsigned long delta_size,
 724                              unsigned long left,
 725                              char *type,
 726                              unsigned long *sizep,
 727                              struct packed_git *p)
 728 {
 729         struct pack_entry base_ent;
 730
 731         if (left < 20)
 732                 die("truncated pack file");
 733
 734         /* The base entry _must_ be in the same pack */
 735         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 736                 die("failed to find delta-pack base object %s",
 737                     sha1_to_hex(base_sha1));
 738
 739         /* We choose to only get the type of the base object and
 740          * ignore potentially corrupt pack file that expects the delta
 741          * based on a base with a wrong size.  This saves tons of
 742          * inflate() calls.
 743          */
 744
 745         if (packed_object_info(&base_ent, type, NULL))
 746                 die("cannot get info for delta-pack base");
 747
 748         if (sizep) {
 749                 const unsigned char *data;
 750                 unsigned char delta_head[64];
 751                 unsigned long result_size;
 752                 z_stream stream;
 753                 int st;
 754
 755                 memset(&stream, 0, sizeof(stream));
 756
 757                 data = stream.next_in = base_sha1 + 20;
 758                 stream.avail_in = left - 20;
 759                 stream.next_out = delta_head;
 760                 stream.avail_out = sizeof(delta_head);
 761
 762                 inflateInit(&stream);
 763                 st = inflate(&stream, Z_FINISH);
 764                 inflateEnd(&stream);
 765                 if ((st != Z_STREAM_END) &&
 766                     stream.total_out != sizeof(delta_head))
 767                         die("delta data unpack-initial failed");
 768
 769                 /* Examine the initial part of the delta to figure out
 770                  * the result size.
 771                  */
 772                 data = delta_head;
 773                 get_delta_hdr_size(&data); /* ignore base size */
 774
 775                 /* Read the result size */
 776                 result_size = get_delta_hdr_size(&data);
 777                 *sizep = result_size;
 778         }
 779         return 0;
 780 }
 781
 782 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 783         enum object_type *type, unsigned long *sizep)
 784 {
 785         unsigned shift;
 786         unsigned char *pack, c;
 787         unsigned long size;
 788
 789         if (offset >= p->pack_size)
 790                 die("object offset outside of pack file");
 791
 792         pack =  p->pack_base + offset;
 793         c = *pack++;
 794         offset++;
 795         *type = (c >> 4) & 7;
 796         size = c & 15;
 797         shift = 4;
 798         while (c & 0x80) {
 799                 if (offset >= p->pack_size)
 800                         die("object offset outside of pack file");
 801                 c = *pack++;
 802                 offset++;
 803                 size += (c & 0x7f) << shift;
 804                 shift += 7;
 805         }
 806         *sizep = size;
 807         return offset;
 808 }
 809
 810 void packed_object_info_detail(struct pack_entry *e,
 811                                char *type,
 812                                unsigned long *size,
 813                                unsigned long *store_size,
 814                                int *delta_chain_length,
 815                                unsigned char *base_sha1)
 816 {
 817         struct packed_git *p = e->p;
 818         unsigned long offset, left;
 819         unsigned char *pack;
 820         enum object_type kind;
 821
 822         offset = unpack_object_header(p, e->offset, &kind, size);
 823         pack = p->pack_base + offset;
 824         left = p->pack_size - offset;
 825         if (kind != OBJ_DELTA)
 826                 *delta_chain_length = 0;
 827         else {
 828                 int chain_length = 0;
 829                 memcpy(base_sha1, pack, 20);
 830                 do {
 831                         struct pack_entry base_ent;
 832                         unsigned long junk;
 833
 834                         find_pack_entry_one(pack, &base_ent, p);
 835                         offset = unpack_object_header(p, base_ent.offset,
 836                                                       &kind, &junk);
 837                         pack = p->pack_base + offset;
 838                         chain_length++;
 839                 } while (kind == OBJ_DELTA);
 840                 *delta_chain_length = chain_length;
 841         }
 842         switch (kind) {
 843         case OBJ_COMMIT:
 844                 strcpy(type, "commit");
 845                 break;
 846         case OBJ_TREE:
 847                 strcpy(type, "tree");
 848                 break;
 849         case OBJ_BLOB:
 850                 strcpy(type, "blob");
 851                 break;
 852         case OBJ_TAG:
 853                 strcpy(type, "tag");
 854                 break;
 855         default:
 856                 die("corrupted pack file %s containing object of kind %d",
 857                     p->pack_name, kind);
 858         }
 859         *store_size = 0; /* notyet */
 860 }
 861
 862 static int packed_object_info(struct pack_entry *entry,
 863                               char *type, unsigned long *sizep)
 864 {
 865         struct packed_git *p = entry->p;
 866         unsigned long offset, size, left;
 867         unsigned char *pack;
 868         enum object_type kind;
 869         int retval;
 870
 871         if (use_packed_git(p))
 872                 die("cannot map packed file");
 873
 874         offset = unpack_object_header(p, entry->offset, &kind, &size);
 875         pack = p->pack_base + offset;
 876         left = p->pack_size - offset;
 877
 878         switch (kind) {
 879         case OBJ_DELTA:
 880                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 881                 unuse_packed_git(p);
 882                 return retval;
 883         case OBJ_COMMIT:
 884                 strcpy(type, "commit");
 885                 break;
 886         case OBJ_TREE:
 887                 strcpy(type, "tree");
 888                 break;
 889         case OBJ_BLOB:
 890                 strcpy(type, "blob");
 891                 break;
 892         case OBJ_TAG:
 893                 strcpy(type, "tag");
 894                 break;
 895         default:
 896                 die("corrupted pack file %s containing object of kind %d",
 897                     p->pack_name, kind);
 898         }
 899         if (sizep)
 900                 *sizep = size;
 901         unuse_packed_git(p);
 902         return 0;
 903 }
 904
 905 /* forward declaration for a mutually recursive function */
 906 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 907
 908 static void *unpack_delta_entry(unsigned char *base_sha1,
 909                                 unsigned long delta_size,
 910                                 unsigned long left,
 911                                 char *type,
 912                                 unsigned long *sizep,
 913                                 struct packed_git *p)
 914 {
 915         struct pack_entry base_ent;
 916         void *data, *delta_data, *result, *base;
 917         unsigned long data_size, result_size, base_size;
 918         z_stream stream;
 919         int st;
 920
 921         if (left < 20)
 922                 die("truncated pack file");
 923         data = base_sha1 + 20;
 924         data_size = left - 20;
 925         delta_data = xmalloc(delta_size);
 926
 927         memset(&stream, 0, sizeof(stream));
 928
 929         stream.next_in = data;
 930         stream.avail_in = data_size;
 931         stream.next_out = delta_data;
 932         stream.avail_out = delta_size;
 933
 934         inflateInit(&stream);
 935         st = inflate(&stream, Z_FINISH);
 936         inflateEnd(&stream);
 937         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 938                 die("delta data unpack failed");
 939
 940         /* The base entry _must_ be in the same pack */
 941         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 942                 die("failed to find delta-pack base object %s",
 943                     sha1_to_hex(base_sha1));
 944         base = unpack_entry_gently(&base_ent, type, &base_size);
 945         if (!base)
 946                 die("failed to read delta-pack base object %s",
 947                     sha1_to_hex(base_sha1));
 948         result = patch_delta(base, base_size,
 949                              delta_data, delta_size,
 950                              &result_size);
 951         if (!result)
 952                 die("failed to apply delta");
 953         free(delta_data);
 954         free(base);
 955         *sizep = result_size;
 956         return result;
 957 }
 958
 959 static void *unpack_non_delta_entry(unsigned char *data,
 960                                     unsigned long size,
 961                                     unsigned long left)
 962 {
 963         int st;
 964         z_stream stream;
 965         unsigned char *buffer;
 966
 967         buffer = xmalloc(size + 1);
 968         buffer[size] = 0;
 969         memset(&stream, 0, sizeof(stream));
 970         stream.next_in = data;
 971         stream.avail_in = left;
 972         stream.next_out = buffer;
 973         stream.avail_out = size;
 974
 975         inflateInit(&stream);
 976         st = inflate(&stream, Z_FINISH);
 977         inflateEnd(&stream);
 978         if ((st != Z_STREAM_END) || stream.total_out != size) {
 979                 free(buffer);
 980                 return NULL;
 981         }
 982
 983         return buffer;
 984 }
 985
 986 static void *unpack_entry(struct pack_entry *entry,
 987                           char *type, unsigned long *sizep)
 988 {
 989         struct packed_git *p = entry->p;
 990         void *retval;
 991
 992         if (use_packed_git(p))
 993                 die("cannot map packed file");
 994         retval = unpack_entry_gently(entry, type, sizep);
 995         unuse_packed_git(p);
 996         if (!retval)
 997                 die("corrupted pack file %s", p->pack_name);
 998         return retval;
 999 }
1000
1001 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1002 void *unpack_entry_gently(struct pack_entry *entry,
1003                           char *type, unsigned long *sizep)
1004 {
1005         struct packed_git *p = entry->p;
1006         unsigned long offset, size, left;
1007         unsigned char *pack;
1008         enum object_type kind;
1009         void *retval;
1010
1011         offset = unpack_object_header(p, entry->offset, &kind, &size);
1012         pack = p->pack_base + offset;
1013         left = p->pack_size - offset;
1014         switch (kind) {
1015         case OBJ_DELTA:
1016                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1017                 return retval;
1018         case OBJ_COMMIT:
1019                 strcpy(type, "commit");
1020                 break;
1021         case OBJ_TREE:
1022                 strcpy(type, "tree");
1023                 break;
1024         case OBJ_BLOB:
1025                 strcpy(type, "blob");
1026                 break;
1027         case OBJ_TAG:
1028                 strcpy(type, "tag");
1029                 break;
1030         default:
1031                 return NULL;
1032         }
1033         *sizep = size;
1034         retval = unpack_non_delta_entry(pack, size, left);
1035         return retval;
1036 }
1037
1038 int num_packed_objects(const struct packed_git *p)
1039 {
1040         /* See check_packed_git_idx() */
1041         return (p->index_size - 20 - 20 - 4*256) / 24;
1042 }
1043
1044 int nth_packed_object_sha1(const struct packed_git *p, int n,
1045                            unsigned char* sha1)
1046 {
1047         void *index = p->index_base + 256;
1048         if (n < 0 || num_packed_objects(p) <= n)
1049                 return -1;
1050         memcpy(sha1, (index + 24 * n + 4), 20);
1051         return 0;
1052 }
1053
1054 int find_pack_entry_one(const unsigned char *sha1,
1055                         struct pack_entry *e, struct packed_git *p)
1056 {
1057         unsigned int *level1_ofs = p->index_base;
1058         int hi = ntohl(level1_ofs[*sha1]);
1059         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1060         void *index = p->index_base + 256;
1061
1062         do {
1063                 int mi = (lo + hi) / 2;
1064                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1065                 if (!cmp) {
1066                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1067                         memcpy(e->sha1, sha1, 20);
1068                         e->p = p;
1069                         return 1;
1070                 }
1071                 if (cmp > 0)
1072                         hi = mi;
1073                 else
1074                         lo = mi+1;
1075         } while (lo < hi);
1076         return 0;
1077 }
1078
1079 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1080 {
1081         struct packed_git *p;
1082         prepare_packed_git();
1083
1084         for (p = packed_git; p; p = p->next) {
1085                 if (find_pack_entry_one(sha1, e, p))
1086                         return 1;
1087         }
1088         return 0;
1089 }
1090
1091 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1092                                   struct packed_git *packs)
1093 {
1094         struct packed_git *p;
1095         struct pack_entry e;
1096
1097         for (p = packs; p; p = p->next) {
1098                 if (find_pack_entry_one(sha1, &e, p))
1099                         return p;
1100         }
1101         return NULL;
1102
1103 }
1104
1105 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1106 {
1107         int status;
1108         unsigned long mapsize, size;
1109         void *map;
1110         z_stream stream;
1111         char hdr[128];
1112
1113         map = map_sha1_file_internal(sha1, &mapsize);
1114         if (!map) {
1115                 struct pack_entry e;
1116
1117                 if (!find_pack_entry(sha1, &e))
1118                         return error("unable to find %s", sha1_to_hex(sha1));
1119                 return packed_object_info(&e, type, sizep);
1120         }
1121         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1122                 status = error("unable to unpack %s header",
1123                                sha1_to_hex(sha1));
1124         if (parse_sha1_header(hdr, type, &size) < 0)
1125                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1126         else {
1127                 status = 0;
1128                 if (sizep)
1129                         *sizep = size;
1130         }
1131         inflateEnd(&stream);
1132         munmap(map, mapsize);
1133         return status;
1134 }
1135
1136 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1137 {
1138         struct pack_entry e;
1139
1140         if (!find_pack_entry(sha1, &e)) {
1141                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1142                 return NULL;
1143         }
1144         return unpack_entry(&e, type, size);
1145 }
1146
1147 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1148 {
1149         unsigned long mapsize;
1150         void *map, *buf;
1151         struct pack_entry e;
1152
1153         if (find_pack_entry(sha1, &e))
1154                 return read_packed_sha1(sha1, type, size);
1155         map = map_sha1_file_internal(sha1, &mapsize);
1156         if (map) {
1157                 buf = unpack_sha1_file(map, mapsize, type, size);
1158                 munmap(map, mapsize);
1159                 return buf;
1160         }
1161         return NULL;
1162 }
1163
1164 void *read_object_with_reference(const unsigned char *sha1,
1165                                  const char *required_type,
1166                                  unsigned long *size,
1167                                  unsigned char *actual_sha1_return)
1168 {
1169         char type[20];
1170         void *buffer;
1171         unsigned long isize;
1172         unsigned char actual_sha1[20];
1173
1174         memcpy(actual_sha1, sha1, 20);
1175         while (1) {
1176                 int ref_length = -1;
1177                 const char *ref_type = NULL;
1178
1179                 buffer = read_sha1_file(actual_sha1, type, &isize);
1180                 if (!buffer)
1181                         return NULL;
1182                 if (!strcmp(type, required_type)) {
1183                         *size = isize;
1184                         if (actual_sha1_return)
1185                                 memcpy(actual_sha1_return, actual_sha1, 20);
1186                         return buffer;
1187                 }
1188                 /* Handle references */
1189                 else if (!strcmp(type, "commit"))
1190                         ref_type = "tree ";
1191                 else if (!strcmp(type, "tag"))
1192                         ref_type = "object ";
1193                 else {
1194                         free(buffer);
1195                         return NULL;
1196                 }
1197                 ref_length = strlen(ref_type);
1198
1199                 if (memcmp(buffer, ref_type, ref_length) ||
1200                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1201                         free(buffer);
1202                         return NULL;
1203                 }
1204                 free(buffer);
1205                 /* Now we have the ID of the referred-to object in
1206                  * actual_sha1.  Check again. */
1207         }
1208 }
1209
1210 char *write_sha1_file_prepare(void *buf,
1211                               unsigned long len,
1212                               const char *type,
1213                               unsigned char *sha1,
1214                               unsigned char *hdr,
1215                               int *hdrlen)
1216 {
1217         SHA_CTX c;
1218
1219         /* Generate the header */
1220         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1221
1222         /* Sha1.. */
1223         SHA1_Init(&c);
1224         SHA1_Update(&c, hdr, *hdrlen);
1225         SHA1_Update(&c, buf, len);
1226         SHA1_Final(sha1, &c);
1227
1228         return sha1_file_name(sha1);
1229 }
1230
1231 /*
1232  * Link the tempfile to the final place, possibly creating the
1233  * last directory level as you do so.
1234  *
1235  * Returns the errno on failure, 0 on success.
1236  */
1237 static int link_temp_to_file(const char *tmpfile, char *filename)
1238 {
1239         int ret;
1240
1241         if (!link(tmpfile, filename))
1242                 return 0;
1243
1244         /*
1245          * Try to mkdir the last path component if that failed
1246          * with an ENOENT.
1247          *
1248          * Re-try the "link()" regardless of whether the mkdir
1249          * succeeds, since a race might mean that somebody
1250          * else succeeded.
1251          */
1252         ret = errno;
1253         if (ret == ENOENT) {
1254                 char *dir = strrchr(filename, '/');
1255                 if (dir) {
1256                         *dir = 0;
1257                         mkdir(filename, 0777);
1258                         *dir = '/';
1259                         if (!link(tmpfile, filename))
1260                                 return 0;
1261                         ret = errno;
1262                 }
1263         }
1264         return ret;
1265 }
1266
1267 /*
1268  * Move the just written object into its final resting place
1269  */
1270 int move_temp_to_file(const char *tmpfile, char *filename)
1271 {
1272         int ret = link_temp_to_file(tmpfile, filename);
1273
1274         /*
1275          * Coda hack - coda doesn't like cross-directory links,
1276          * so we fall back to a rename, which will mean that it
1277          * won't be able to check collisions, but that's not a
1278          * big deal.
1279          *
1280          * The same holds for FAT formatted media.
1281          *
1282          * When this succeeds, we just return 0. We have nothing
1283          * left to unlink.
1284          */
1285         if (ret && ret != EEXIST) {
1286                 if (!rename(tmpfile, filename))
1287                         return 0;
1288                 ret = errno;
1289         }
1290         unlink(tmpfile);
1291         if (ret) {
1292                 if (ret != EEXIST) {
1293                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1294                         return -1;
1295                 }
1296                 /* FIXME!!! Collision check here ? */
1297         }
1298
1299         return 0;
1300 }
1301
1302 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1303 {
1304         int size;
1305         unsigned char *compressed;
1306         z_stream stream;
1307         unsigned char sha1[20];
1308         char *filename;
1309         static char tmpfile[PATH_MAX];
1310         unsigned char hdr[50];
1311         int fd, hdrlen;
1312
1313         /* Normally if we have it in the pack then we do not bother writing
1314          * it out into .git/objects/??/?{38} file.
1315          */
1316         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1317         if (returnsha1)
1318                 memcpy(returnsha1, sha1, 20);
1319         if (has_sha1_file(sha1))
1320                 return 0;
1321         fd = open(filename, O_RDONLY);
1322         if (fd >= 0) {
1323                 /*
1324                  * FIXME!!! We might do collision checking here, but we'd
1325                  * need to uncompress the old file and check it. Later.
1326                  */
1327                 close(fd);
1328                 return 0;
1329         }
1330
1331         if (errno != ENOENT) {
1332                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1333                 return -1;
1334         }
1335
1336         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1337
1338         fd = mkstemp(tmpfile);
1339         if (fd < 0) {
1340                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1341                 return -1;
1342         }
1343
1344         /* Set it up */
1345         memset(&stream, 0, sizeof(stream));
1346         deflateInit(&stream, Z_BEST_COMPRESSION);
1347         size = deflateBound(&stream, len+hdrlen);
1348         compressed = xmalloc(size);
1349
1350         /* Compress it */
1351         stream.next_out = compressed;
1352         stream.avail_out = size;
1353
1354         /* First header.. */
1355         stream.next_in = hdr;
1356         stream.avail_in = hdrlen;
1357         while (deflate(&stream, 0) == Z_OK)
1358                 /* nothing */;
1359
1360         /* Then the data itself.. */
1361         stream.next_in = buf;
1362         stream.avail_in = len;
1363         while (deflate(&stream, Z_FINISH) == Z_OK)
1364                 /* nothing */;
1365         deflateEnd(&stream);
1366         size = stream.total_out;
1367
1368         if (write(fd, compressed, size) != size)
1369                 die("unable to write file");
1370         fchmod(fd, 0444);
1371         close(fd);
1372         free(compressed);
1373
1374         return move_temp_to_file(tmpfile, filename);
1375 }
1376
1377 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1378 {
1379         ssize_t size;
1380         unsigned long objsize;
1381         int posn = 0;
1382         void *map = map_sha1_file_internal(sha1, &objsize);
1383         void *buf = map;
1384         void *temp_obj = NULL;
1385         z_stream stream;
1386
1387         if (!buf) {
1388                 unsigned char *unpacked;
1389                 unsigned long len;
1390                 char type[20];
1391                 char hdr[50];
1392                 int hdrlen;
1393                 // need to unpack and recompress it by itself
1394                 unpacked = read_packed_sha1(sha1, type, &len);
1395
1396                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1397
1398                 /* Set it up */
1399                 memset(&stream, 0, sizeof(stream));
1400                 deflateInit(&stream, Z_BEST_COMPRESSION);
1401                 size = deflateBound(&stream, len + hdrlen);
1402                 temp_obj = buf = xmalloc(size);
1403
1404                 /* Compress it */
1405                 stream.next_out = buf;
1406                 stream.avail_out = size;
1407
1408                 /* First header.. */
1409                 stream.next_in = (void *)hdr;
1410                 stream.avail_in = hdrlen;
1411                 while (deflate(&stream, 0) == Z_OK)
1412                         /* nothing */;
1413
1414                 /* Then the data itself.. */
1415                 stream.next_in = unpacked;
1416                 stream.avail_in = len;
1417                 while (deflate(&stream, Z_FINISH) == Z_OK)
1418                         /* nothing */;
1419                 deflateEnd(&stream);
1420                 free(unpacked);
1421
1422                 objsize = stream.total_out;
1423         }
1424
1425         do {
1426                 size = write(fd, buf + posn, objsize - posn);
1427                 if (size <= 0) {
1428                         if (!size) {
1429                                 fprintf(stderr, "write closed\n");
1430                         } else {
1431                                 perror("write ");
1432                         }
1433                         return -1;
1434                 }
1435                 posn += size;
1436         } while (posn < objsize);
1437
1438         if (map)
1439                 munmap(map, objsize);
1440         if (temp_obj)
1441                 free(temp_obj);
1442
1443         return 0;
1444 }
1445
1446 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1447                        size_t bufsize, size_t *bufposn)
1448 {
1449         char tmpfile[PATH_MAX];
1450         int local;
1451         z_stream stream;
1452         unsigned char real_sha1[20];
1453         unsigned char discard[4096];
1454         int ret;
1455         SHA_CTX c;
1456
1457         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1458
1459         local = mkstemp(tmpfile);
1460         if (local < 0)
1461                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1462
1463         memset(&stream, 0, sizeof(stream));
1464
1465         inflateInit(&stream);
1466
1467         SHA1_Init(&c);
1468
1469         do {
1470                 ssize_t size;
1471                 if (*bufposn) {
1472                         stream.avail_in = *bufposn;
1473                         stream.next_in = (unsigned char *) buffer;
1474                         do {
1475                                 stream.next_out = discard;
1476                                 stream.avail_out = sizeof(discard);
1477                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1478                                 SHA1_Update(&c, discard, sizeof(discard) -
1479                                             stream.avail_out);
1480                         } while (stream.avail_in && ret == Z_OK);
1481                         write(local, buffer, *bufposn - stream.avail_in);
1482                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1483                                 stream.avail_in);
1484                         *bufposn = stream.avail_in;
1485                         if (ret != Z_OK)
1486                                 break;
1487                 }
1488                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1489                 if (size <= 0) {
1490                         close(local);
1491                         unlink(tmpfile);
1492                         if (!size)
1493                                 return error("Connection closed?");
1494                         perror("Reading from connection");
1495                         return -1;
1496                 }
1497                 *bufposn += size;
1498         } while (1);
1499         inflateEnd(&stream);
1500
1501         close(local);
1502         SHA1_Final(real_sha1, &c);
1503         if (ret != Z_STREAM_END) {
1504                 unlink(tmpfile);
1505                 return error("File %s corrupted", sha1_to_hex(sha1));
1506         }
1507         if (memcmp(sha1, real_sha1, 20)) {
1508                 unlink(tmpfile);
1509                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1510         }
1511
1512         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1513 }
1514
1515 int has_pack_index(const unsigned char *sha1)
1516 {
1517         struct stat st;
1518         if (stat(sha1_pack_index_name(sha1), &st))
1519                 return 0;
1520         return 1;
1521 }
1522
1523 int has_pack_file(const unsigned char *sha1)
1524 {
1525         struct stat st;
1526         if (stat(sha1_pack_name(sha1), &st))
1527                 return 0;
1528         return 1;
1529 }
1530
1531 int has_sha1_pack(const unsigned char *sha1)
1532 {
1533         struct pack_entry e;
1534         return find_pack_entry(sha1, &e);
1535 }
1536
1537 int has_sha1_file(const unsigned char *sha1)
1538 {
1539         struct stat st;
1540         struct pack_entry e;
1541
1542         if (find_pack_entry(sha1, &e))
1543                 return 1;
1544         return find_sha1_file(sha1, &st) ? 1 : 0;
1545 }
1546
1547 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1548 {
1549         unsigned long size = 4096;
1550         char *buf = malloc(size);
1551         int iret, ret;
1552         unsigned long off = 0;
1553         unsigned char hdr[50];
1554         int hdrlen;
1555         do {
1556                 iret = read(fd, buf + off, size - off);
1557                 if (iret > 0) {
1558                         off += iret;
1559                         if (off == size) {
1560                                 size *= 2;
1561                                 buf = realloc(buf, size);
1562                         }
1563                 }
1564         } while (iret > 0);
1565         if (iret < 0) {
1566                 free(buf);
1567                 return -1;
1568         }
1569         if (!type)
1570                 type = "blob";
1571         if (write_object)
1572                 ret = write_sha1_file(buf, off, type, sha1);
1573         else {
1574                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1575                 ret = 0;
1576         }
1577         free(buf);
1578         return ret;
1579 }
1580
1581 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1582 {
1583         unsigned long size = st->st_size;
1584         void *buf;
1585         int ret;
1586         unsigned char hdr[50];
1587         int hdrlen;
1588
1589         buf = "";
1590         if (size)
1591                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1592         close(fd);
1593         if (buf == MAP_FAILED)
1594                 return -1;
1595
1596         if (!type)
1597                 type = "blob";
1598         if (write_object)
1599                 ret = write_sha1_file(buf, size, type, sha1);
1600         else {
1601                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1602                 ret = 0;
1603         }
1604         if (size)
1605                 munmap(buf, size);
1606         return ret;
1607 }
1608
1609 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1610 {
1611         int fd;
1612         char *target;
1613
1614         switch (st->st_mode & S_IFMT) {
1615         case S_IFREG:
1616                 fd = open(path, O_RDONLY);
1617                 if (fd < 0)
1618                         return error("open(\"%s\"): %s", path,
1619                                      strerror(errno));
1620                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1621                         return error("%s: failed to insert into database",
1622                                      path);
1623                 break;
1624         case S_IFLNK:
1625                 target = xmalloc(st->st_size+1);
1626                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1627                         char *errstr = strerror(errno);
1628                         free(target);
1629                         return error("readlink(\"%s\"): %s", path,
1630                                      errstr);
1631                 }
1632                 if (!write_object) {
1633                         unsigned char hdr[50];
1634                         int hdrlen;
1635                         write_sha1_file_prepare(target, st->st_size, "blob",
1636                                                 sha1, hdr, &hdrlen);
1637                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1638                         return error("%s: failed to insert into database",
1639                                      path);
1640                 free(target);
1641                 break;
1642         default:
1643                 return error("%s: unsupported file type", path);
1644         }
1645         return 0;
1646 }