sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include "cache.h"
  10 #include "delta.h"
  11 #include "pack.h"
  12
  13 #ifndef O_NOATIME
  14 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  15 #define O_NOATIME 01000000
  16 #else
  17 #define O_NOATIME 0
  18 #endif
  19 #endif
  20
  21 const unsigned char null_sha1[20] = { 0, };
  22
  23 static unsigned int sha1_file_open_flag = O_NOATIME;
  24
  25 static unsigned hexval(char c)
  26 {
  27         if (c >= '0' && c <= '9')
  28                 return c - '0';
  29         if (c >= 'a' && c <= 'f')
  30                 return c - 'a' + 10;
  31         if (c >= 'A' && c <= 'F')
  32                 return c - 'A' + 10;
  33         return ~0;
  34 }
  35
  36 int get_sha1_hex(const char *hex, unsigned char *sha1)
  37 {
  38         int i;
  39         for (i = 0; i < 20; i++) {
  40                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  41                 if (val & ~0xff)
  42                         return -1;
  43                 *sha1++ = val;
  44                 hex += 2;
  45         }
  46         return 0;
  47 }
  48
  49 int adjust_shared_perm(const char *path)
  50 {
  51         struct stat st;
  52         int mode;
  53
  54         if (!shared_repository)
  55                 return 0;
  56         if (lstat(path, &st) < 0)
  57                 return -1;
  58         mode = st.st_mode;
  59         if (mode & S_IRUSR)
  60                 mode |= S_IRGRP;
  61         if (mode & S_IWUSR)
  62                 mode |= S_IWGRP;
  63         if (mode & S_IXUSR)
  64                 mode |= S_IXGRP;
  65         if (S_ISDIR(mode))
  66                 mode |= S_ISGID;
  67         if (chmod(path, mode) < 0)
  68                 return -2;
  69         return 0;
  70 }
  71
  72 int safe_create_leading_directories(char *path)
  73 {
  74         char *pos = path;
  75         struct stat st;
  76
  77         if (*pos == '/')
  78                 pos++;
  79
  80         while (pos) {
  81                 pos = strchr(pos, '/');
  82                 if (!pos)
  83                         break;
  84                 *pos = 0;
  85                 if (!stat(path, &st)) {
  86                         /* path exists */
  87                         if (!S_ISDIR(st.st_mode)) {
  88                                 *pos = '/';
  89                                 return -3;
  90                         }
  91                 }
  92                 else if (mkdir(path, 0777)) {
  93                         *pos = '/';
  94                         return -1;
  95                 }
  96                 else if (adjust_shared_perm(path)) {
  97                         *pos = '/';
  98                         return -2;
  99                 }
 100                 *pos++ = '/';
 101         }
 102         return 0;
 103 }
 104
 105 char * sha1_to_hex(const unsigned char *sha1)
 106 {
 107         static char buffer[50];
 108         static const char hex[] = "0123456789abcdef";
 109         char *buf = buffer;
 110         int i;
 111
 112         for (i = 0; i < 20; i++) {
 113                 unsigned int val = *sha1++;
 114                 *buf++ = hex[val >> 4];
 115                 *buf++ = hex[val & 0xf];
 116         }
 117         *buf = '\0';
 118
 119         return buffer;
 120 }
 121
 122 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 123 {
 124         int i;
 125         for (i = 0; i < 20; i++) {
 126                 static char hex[] = "0123456789abcdef";
 127                 unsigned int val = sha1[i];
 128                 char *pos = pathbuf + i*2 + (i > 0);
 129                 *pos++ = hex[val >> 4];
 130                 *pos = hex[val & 0xf];
 131         }
 132 }
 133
 134 /*
 135  * NOTE! This returns a statically allocated buffer, so you have to be
 136  * careful about using it. Do a "strdup()" if you need to save the
 137  * filename.
 138  *
 139  * Also note that this returns the location for creating.  Reading
 140  * SHA1 file can happen from any alternate directory listed in the
 141  * DB_ENVIRONMENT environment variable if it is not found in
 142  * the primary object database.
 143  */
 144 char *sha1_file_name(const unsigned char *sha1)
 145 {
 146         static char *name, *base;
 147
 148         if (!base) {
 149                 const char *sha1_file_directory = get_object_directory();
 150                 int len = strlen(sha1_file_directory);
 151                 base = xmalloc(len + 60);
 152                 memcpy(base, sha1_file_directory, len);
 153                 memset(base+len, 0, 60);
 154                 base[len] = '/';
 155                 base[len+3] = '/';
 156                 name = base + len + 1;
 157         }
 158         fill_sha1_path(name, sha1);
 159         return base;
 160 }
 161
 162 char *sha1_pack_name(const unsigned char *sha1)
 163 {
 164         static const char hex[] = "0123456789abcdef";
 165         static char *name, *base, *buf;
 166         int i;
 167
 168         if (!base) {
 169                 const char *sha1_file_directory = get_object_directory();
 170                 int len = strlen(sha1_file_directory);
 171                 base = xmalloc(len + 60);
 172                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 173                 name = base + len + 11;
 174         }
 175
 176         buf = name;
 177
 178         for (i = 0; i < 20; i++) {
 179                 unsigned int val = *sha1++;
 180                 *buf++ = hex[val >> 4];
 181                 *buf++ = hex[val & 0xf];
 182         }
 183
 184         return base;
 185 }
 186
 187 char *sha1_pack_index_name(const unsigned char *sha1)
 188 {
 189         static const char hex[] = "0123456789abcdef";
 190         static char *name, *base, *buf;
 191         int i;
 192
 193         if (!base) {
 194                 const char *sha1_file_directory = get_object_directory();
 195                 int len = strlen(sha1_file_directory);
 196                 base = xmalloc(len + 60);
 197                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 198                 name = base + len + 11;
 199         }
 200
 201         buf = name;
 202
 203         for (i = 0; i < 20; i++) {
 204                 unsigned int val = *sha1++;
 205                 *buf++ = hex[val >> 4];
 206                 *buf++ = hex[val & 0xf];
 207         }
 208
 209         return base;
 210 }
 211
 212 struct alternate_object_database *alt_odb_list;
 213 static struct alternate_object_database **alt_odb_tail;
 214
 215 /*
 216  * Prepare alternate object database registry.
 217  *
 218  * The variable alt_odb_list points at the list of struct
 219  * alternate_object_database.  The elements on this list come from
 220  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 221  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 222  * whose contents is similar to that environment variable but can be
 223  * LF separated.  Its base points at a statically allocated buffer that
 224  * contains "/the/directory/corresponding/to/.git/objects/...", while
 225  * its name points just after the slash at the end of ".git/objects/"
 226  * in the example above, and has enough space to hold 40-byte hex
 227  * SHA1, an extra slash for the first level indirection, and the
 228  * terminating NUL.
 229  */
 230 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 231                                  const char *relative_base)
 232 {
 233         const char *cp, *last;
 234         struct alternate_object_database *ent;
 235         const char *objdir = get_object_directory();
 236         int base_len = -1;
 237
 238         last = alt;
 239         while (last < ep) {
 240                 cp = last;
 241                 if (cp < ep && *cp == '#') {
 242                         while (cp < ep && *cp != sep)
 243                                 cp++;
 244                         last = cp + 1;
 245                         continue;
 246                 }
 247                 for ( ; cp < ep && *cp != sep; cp++)
 248                         ;
 249                 if (last != cp) {
 250                         struct alternate_object_database *alt;
 251                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 252                         int pfxlen = cp - last;
 253                         int entlen = pfxlen + 43;
 254
 255                         if (*last != '/' && relative_base) {
 256                                 /* Relative alt-odb */
 257                                 if (base_len < 0)
 258                                         base_len = strlen(relative_base) + 1;
 259                                 entlen += base_len;
 260                                 pfxlen += base_len;
 261                         }
 262                         ent = xmalloc(sizeof(*ent) + entlen);
 263
 264                         if (*last != '/' && relative_base) {
 265                                 memcpy(ent->base, relative_base, base_len - 1);
 266                                 ent->base[base_len - 1] = '/';
 267                                 memcpy(ent->base + base_len,
 268                                        last, cp - last);
 269                         }
 270                         else
 271                                 memcpy(ent->base, last, pfxlen);
 272                         ent->name = ent->base + pfxlen + 1;
 273                         ent->base[pfxlen] = ent->base[pfxlen + 3] = '/';
 274                         ent->base[entlen-1] = 0;
 275
 276                         /* Prevent the common mistake of listing the same
 277                          * thing twice, or object directory itself.
 278                          */
 279                         for (alt = alt_odb_list; alt; alt = alt->next)
 280                                 if (!memcmp(ent->base, alt->base, pfxlen))
 281                                         goto bad;
 282                         if (!memcmp(ent->base, objdir, pfxlen)) {
 283                         bad:
 284                                 free(ent);
 285                         }
 286                         else {
 287                                 *alt_odb_tail = ent;
 288                                 alt_odb_tail = &(ent->next);
 289                                 ent->next = NULL;
 290                         }
 291                 }
 292                 while (cp < ep && *cp == sep)
 293                         cp++;
 294                 last = cp;
 295         }
 296 }
 297
 298 void prepare_alt_odb(void)
 299 {
 300         char path[PATH_MAX];
 301         char *map;
 302         int fd;
 303         struct stat st;
 304         char *alt;
 305
 306         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 307         if (!alt) alt = "";
 308
 309         if (alt_odb_tail)
 310                 return;
 311         alt_odb_tail = &alt_odb_list;
 312         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 313
 314         sprintf(path, "%s/info/alternates", get_object_directory());
 315         fd = open(path, O_RDONLY);
 316         if (fd < 0)
 317                 return;
 318         if (fstat(fd, &st) || (st.st_size == 0)) {
 319                 close(fd);
 320                 return;
 321         }
 322         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 323         close(fd);
 324         if (map == MAP_FAILED)
 325                 return;
 326
 327         link_alt_odb_entries(map, map + st.st_size, '\n',
 328                              get_object_directory());
 329         munmap(map, st.st_size);
 330 }
 331
 332 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 333 {
 334         char *name = sha1_file_name(sha1);
 335         struct alternate_object_database *alt;
 336
 337         if (!stat(name, st))
 338                 return name;
 339         prepare_alt_odb();
 340         for (alt = alt_odb_list; alt; alt = alt->next) {
 341                 name = alt->name;
 342                 fill_sha1_path(name, sha1);
 343                 if (!stat(alt->base, st))
 344                         return alt->base;
 345         }
 346         return NULL;
 347 }
 348
 349 #define PACK_MAX_SZ (1<<26)
 350 static int pack_used_ctr;
 351 static unsigned long pack_mapped;
 352 struct packed_git *packed_git;
 353
 354 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 355                                 void **idx_map_)
 356 {
 357         void *idx_map;
 358         unsigned int *index;
 359         unsigned long idx_size;
 360         int nr, i;
 361         int fd = open(path, O_RDONLY);
 362         struct stat st;
 363         if (fd < 0)
 364                 return -1;
 365         if (fstat(fd, &st)) {
 366                 close(fd);
 367                 return -1;
 368         }
 369         idx_size = st.st_size;
 370         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 371         close(fd);
 372         if (idx_map == MAP_FAILED)
 373                 return -1;
 374
 375         index = idx_map;
 376         *idx_map_ = idx_map;
 377         *idx_size_ = idx_size;
 378
 379         /* check index map */
 380         if (idx_size < 4*256 + 20 + 20)
 381                 return error("index file too small");
 382         nr = 0;
 383         for (i = 0; i < 256; i++) {
 384                 unsigned int n = ntohl(index[i]);
 385                 if (n < nr)
 386                         return error("non-monotonic index");
 387                 nr = n;
 388         }
 389
 390         /*
 391          * Total size:
 392          *  - 256 index entries 4 bytes each
 393          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 394          *  - 20-byte SHA1 of the packfile
 395          *  - 20-byte SHA1 file checksum
 396          */
 397         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 398                 return error("wrong index file size");
 399
 400         return 0;
 401 }
 402
 403 static int unuse_one_packed_git(void)
 404 {
 405         struct packed_git *p, *lru = NULL;
 406
 407         for (p = packed_git; p; p = p->next) {
 408                 if (p->pack_use_cnt || !p->pack_base)
 409                         continue;
 410                 if (!lru || p->pack_last_used < lru->pack_last_used)
 411                         lru = p;
 412         }
 413         if (!lru)
 414                 return 0;
 415         munmap(lru->pack_base, lru->pack_size);
 416         lru->pack_base = NULL;
 417         return 1;
 418 }
 419
 420 void unuse_packed_git(struct packed_git *p)
 421 {
 422         p->pack_use_cnt--;
 423 }
 424
 425 int use_packed_git(struct packed_git *p)
 426 {
 427         if (!p->pack_size) {
 428                 struct stat st;
 429                 // We created the struct before we had the pack
 430                 stat(p->pack_name, &st);
 431                 if (!S_ISREG(st.st_mode))
 432                         die("packfile %s not a regular file", p->pack_name);
 433                 p->pack_size = st.st_size;
 434         }
 435         if (!p->pack_base) {
 436                 int fd;
 437                 struct stat st;
 438                 void *map;
 439
 440                 pack_mapped += p->pack_size;
 441                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 442                         ; /* nothing */
 443                 fd = open(p->pack_name, O_RDONLY);
 444                 if (fd < 0)
 445                         die("packfile %s cannot be opened", p->pack_name);
 446                 if (fstat(fd, &st)) {
 447                         close(fd);
 448                         die("packfile %s cannot be opened", p->pack_name);
 449                 }
 450                 if (st.st_size != p->pack_size)
 451                         die("packfile %s size mismatch.", p->pack_name);
 452                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 453                 close(fd);
 454                 if (map == MAP_FAILED)
 455                         die("packfile %s cannot be mapped.", p->pack_name);
 456                 p->pack_base = map;
 457
 458                 /* Check if the pack file matches with the index file.
 459                  * this is cheap.
 460                  */
 461                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 462                            p->pack_base + p->pack_size - 20, 20)) {
 463
 464                         die("packfile %s does not match index.", p->pack_name);
 465                 }
 466         }
 467         p->pack_last_used = pack_used_ctr++;
 468         p->pack_use_cnt++;
 469         return 0;
 470 }
 471
 472 struct packed_git *add_packed_git(char *path, int path_len, int local)
 473 {
 474         struct stat st;
 475         struct packed_git *p;
 476         unsigned long idx_size;
 477         void *idx_map;
 478         unsigned char sha1[20];
 479
 480         if (check_packed_git_idx(path, &idx_size, &idx_map))
 481                 return NULL;
 482
 483         /* do we have a corresponding .pack file? */
 484         strcpy(path + path_len - 4, ".pack");
 485         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 486                 munmap(idx_map, idx_size);
 487                 return NULL;
 488         }
 489         /* ok, it looks sane as far as we can check without
 490          * actually mapping the pack file.
 491          */
 492         p = xmalloc(sizeof(*p) + path_len + 2);
 493         strcpy(p->pack_name, path);
 494         p->index_size = idx_size;
 495         p->pack_size = st.st_size;
 496         p->index_base = idx_map;
 497         p->next = NULL;
 498         p->pack_base = NULL;
 499         p->pack_last_used = 0;
 500         p->pack_use_cnt = 0;
 501         p->pack_local = local;
 502         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 503                 memcpy(p->sha1, sha1, 20);
 504         return p;
 505 }
 506
 507 struct packed_git *parse_pack_index(unsigned char *sha1)
 508 {
 509         char *path = sha1_pack_index_name(sha1);
 510         return parse_pack_index_file(sha1, path);
 511 }
 512
 513 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 514 {
 515         struct packed_git *p;
 516         unsigned long idx_size;
 517         void *idx_map;
 518         char *path;
 519
 520         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 521                 return NULL;
 522
 523         path = sha1_pack_name(sha1);
 524
 525         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 526         strcpy(p->pack_name, path);
 527         p->index_size = idx_size;
 528         p->pack_size = 0;
 529         p->index_base = idx_map;
 530         p->next = NULL;
 531         p->pack_base = NULL;
 532         p->pack_last_used = 0;
 533         p->pack_use_cnt = 0;
 534         memcpy(p->sha1, sha1, 20);
 535         return p;
 536 }
 537
 538 void install_packed_git(struct packed_git *pack)
 539 {
 540         pack->next = packed_git;
 541         packed_git = pack;
 542 }
 543
 544 static void prepare_packed_git_one(char *objdir, int local)
 545 {
 546         char path[PATH_MAX];
 547         int len;
 548         DIR *dir;
 549         struct dirent *de;
 550
 551         sprintf(path, "%s/pack", objdir);
 552         len = strlen(path);
 553         dir = opendir(path);
 554         if (!dir)
 555                 return;
 556         path[len++] = '/';
 557         while ((de = readdir(dir)) != NULL) {
 558                 int namelen = strlen(de->d_name);
 559                 struct packed_git *p;
 560
 561                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 562                         continue;
 563
 564                 /* we have .idx.  Is it a file we can map? */
 565                 strcpy(path + len, de->d_name);
 566                 p = add_packed_git(path, len + namelen, local);
 567                 if (!p)
 568                         continue;
 569                 p->next = packed_git;
 570                 packed_git = p;
 571         }
 572         closedir(dir);
 573 }
 574
 575 void prepare_packed_git(void)
 576 {
 577         static int run_once = 0;
 578         struct alternate_object_database *alt;
 579
 580         if (run_once)
 581                 return;
 582         prepare_packed_git_one(get_object_directory(), 1);
 583         prepare_alt_odb();
 584         for (alt = alt_odb_list; alt; alt = alt->next) {
 585                 alt->name[-1] = 0;
 586                 prepare_packed_git_one(alt->base, 0);
 587                 alt->name[-1] = '/';
 588         }
 589         run_once = 1;
 590 }
 591
 592 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 593 {
 594         char header[100];
 595         unsigned char real_sha1[20];
 596         SHA_CTX c;
 597
 598         SHA1_Init(&c);
 599         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 600         SHA1_Update(&c, map, size);
 601         SHA1_Final(real_sha1, &c);
 602         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 603 }
 604
 605 static void *map_sha1_file_internal(const unsigned char *sha1,
 606                                     unsigned long *size)
 607 {
 608         struct stat st;
 609         void *map;
 610         int fd;
 611         char *filename = find_sha1_file(sha1, &st);
 612
 613         if (!filename) {
 614                 return NULL;
 615         }
 616
 617         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 618         if (fd < 0) {
 619                 /* See if it works without O_NOATIME */
 620                 switch (sha1_file_open_flag) {
 621                 default:
 622                         fd = open(filename, O_RDONLY);
 623                         if (fd >= 0)
 624                                 break;
 625                 /* Fallthrough */
 626                 case 0:
 627                         return NULL;
 628                 }
 629
 630                 /* If it failed once, it will probably fail again.
 631                  * Stop using O_NOATIME
 632                  */
 633                 sha1_file_open_flag = 0;
 634         }
 635         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 636         close(fd);
 637         if (map == MAP_FAILED)
 638                 return NULL;
 639         *size = st.st_size;
 640         return map;
 641 }
 642
 643 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 644 {
 645         /* Get the data stream */
 646         memset(stream, 0, sizeof(*stream));
 647         stream->next_in = map;
 648         stream->avail_in = mapsize;
 649         stream->next_out = buffer;
 650         stream->avail_out = size;
 651
 652         inflateInit(stream);
 653         return inflate(stream, 0);
 654 }
 655
 656 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 657 {
 658         int bytes = strlen(buffer) + 1;
 659         unsigned char *buf = xmalloc(1+size);
 660
 661         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 662         bytes = stream->total_out - bytes;
 663         if (bytes < size) {
 664                 stream->next_out = buf + bytes;
 665                 stream->avail_out = size - bytes;
 666                 while (inflate(stream, Z_FINISH) == Z_OK)
 667                         /* nothing */;
 668         }
 669         buf[size] = 0;
 670         inflateEnd(stream);
 671         return buf;
 672 }
 673
 674 /*
 675  * We used to just use "sscanf()", but that's actually way
 676  * too permissive for what we want to check. So do an anal
 677  * object header parse by hand.
 678  */
 679 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 680 {
 681         int i;
 682         unsigned long size;
 683
 684         /*
 685          * The type can be at most ten bytes (including the
 686          * terminating '\0' that we add), and is followed by
 687          * a space.
 688          */
 689         i = 10;
 690         for (;;) {
 691                 char c = *hdr++;
 692                 if (c == ' ')
 693                         break;
 694                 if (!--i)
 695                         return -1;
 696                 *type++ = c;
 697         }
 698         *type = 0;
 699
 700         /*
 701          * The length must follow immediately, and be in canonical
 702          * decimal format (ie "010" is not valid).
 703          */
 704         size = *hdr++ - '0';
 705         if (size > 9)
 706                 return -1;
 707         if (size) {
 708                 for (;;) {
 709                         unsigned long c = *hdr - '0';
 710                         if (c > 9)
 711                                 break;
 712                         hdr++;
 713                         size = size * 10 + c;
 714                 }
 715         }
 716         *sizep = size;
 717
 718         /*
 719          * The length must be followed by a zero byte
 720          */
 721         return *hdr ? -1 : 0;
 722 }
 723
 724 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 725 {
 726         int ret;
 727         z_stream stream;
 728         char hdr[8192];
 729
 730         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 731         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 732                 return NULL;
 733
 734         return unpack_sha1_rest(&stream, hdr, *size);
 735 }
 736
 737 /* forward declaration for a mutually recursive function */
 738 static int packed_object_info(struct pack_entry *entry,
 739                               char *type, unsigned long *sizep);
 740
 741 static int packed_delta_info(unsigned char *base_sha1,
 742                              unsigned long delta_size,
 743                              unsigned long left,
 744                              char *type,
 745                              unsigned long *sizep,
 746                              struct packed_git *p)
 747 {
 748         struct pack_entry base_ent;
 749
 750         if (left < 20)
 751                 die("truncated pack file");
 752
 753         /* The base entry _must_ be in the same pack */
 754         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 755                 die("failed to find delta-pack base object %s",
 756                     sha1_to_hex(base_sha1));
 757
 758         /* We choose to only get the type of the base object and
 759          * ignore potentially corrupt pack file that expects the delta
 760          * based on a base with a wrong size.  This saves tons of
 761          * inflate() calls.
 762          */
 763
 764         if (packed_object_info(&base_ent, type, NULL))
 765                 die("cannot get info for delta-pack base");
 766
 767         if (sizep) {
 768                 const unsigned char *data;
 769                 unsigned char delta_head[64];
 770                 unsigned long result_size;
 771                 z_stream stream;
 772                 int st;
 773
 774                 memset(&stream, 0, sizeof(stream));
 775
 776                 data = stream.next_in = base_sha1 + 20;
 777                 stream.avail_in = left - 20;
 778                 stream.next_out = delta_head;
 779                 stream.avail_out = sizeof(delta_head);
 780
 781                 inflateInit(&stream);
 782                 st = inflate(&stream, Z_FINISH);
 783                 inflateEnd(&stream);
 784                 if ((st != Z_STREAM_END) &&
 785                     stream.total_out != sizeof(delta_head))
 786                         die("delta data unpack-initial failed");
 787
 788                 /* Examine the initial part of the delta to figure out
 789                  * the result size.
 790                  */
 791                 data = delta_head;
 792                 get_delta_hdr_size(&data); /* ignore base size */
 793
 794                 /* Read the result size */
 795                 result_size = get_delta_hdr_size(&data);
 796                 *sizep = result_size;
 797         }
 798         return 0;
 799 }
 800
 801 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 802         enum object_type *type, unsigned long *sizep)
 803 {
 804         unsigned shift;
 805         unsigned char *pack, c;
 806         unsigned long size;
 807
 808         if (offset >= p->pack_size)
 809                 die("object offset outside of pack file");
 810
 811         pack =  p->pack_base + offset;
 812         c = *pack++;
 813         offset++;
 814         *type = (c >> 4) & 7;
 815         size = c & 15;
 816         shift = 4;
 817         while (c & 0x80) {
 818                 if (offset >= p->pack_size)
 819                         die("object offset outside of pack file");
 820                 c = *pack++;
 821                 offset++;
 822                 size += (c & 0x7f) << shift;
 823                 shift += 7;
 824         }
 825         *sizep = size;
 826         return offset;
 827 }
 828
 829 void packed_object_info_detail(struct pack_entry *e,
 830                                char *type,
 831                                unsigned long *size,
 832                                unsigned long *store_size,
 833                                int *delta_chain_length,
 834                                unsigned char *base_sha1)
 835 {
 836         struct packed_git *p = e->p;
 837         unsigned long offset, left;
 838         unsigned char *pack;
 839         enum object_type kind;
 840
 841         offset = unpack_object_header(p, e->offset, &kind, size);
 842         pack = p->pack_base + offset;
 843         left = p->pack_size - offset;
 844         if (kind != OBJ_DELTA)
 845                 *delta_chain_length = 0;
 846         else {
 847                 int chain_length = 0;
 848                 memcpy(base_sha1, pack, 20);
 849                 do {
 850                         struct pack_entry base_ent;
 851                         unsigned long junk;
 852
 853                         find_pack_entry_one(pack, &base_ent, p);
 854                         offset = unpack_object_header(p, base_ent.offset,
 855                                                       &kind, &junk);
 856                         pack = p->pack_base + offset;
 857                         chain_length++;
 858                 } while (kind == OBJ_DELTA);
 859                 *delta_chain_length = chain_length;
 860         }
 861         switch (kind) {
 862         case OBJ_COMMIT:
 863                 strcpy(type, "commit");
 864                 break;
 865         case OBJ_TREE:
 866                 strcpy(type, "tree");
 867                 break;
 868         case OBJ_BLOB:
 869                 strcpy(type, "blob");
 870                 break;
 871         case OBJ_TAG:
 872                 strcpy(type, "tag");
 873                 break;
 874         default:
 875                 die("corrupted pack file %s containing object of kind %d",
 876                     p->pack_name, kind);
 877         }
 878         *store_size = 0; /* notyet */
 879 }
 880
 881 static int packed_object_info(struct pack_entry *entry,
 882                               char *type, unsigned long *sizep)
 883 {
 884         struct packed_git *p = entry->p;
 885         unsigned long offset, size, left;
 886         unsigned char *pack;
 887         enum object_type kind;
 888         int retval;
 889
 890         if (use_packed_git(p))
 891                 die("cannot map packed file");
 892
 893         offset = unpack_object_header(p, entry->offset, &kind, &size);
 894         pack = p->pack_base + offset;
 895         left = p->pack_size - offset;
 896
 897         switch (kind) {
 898         case OBJ_DELTA:
 899                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 900                 unuse_packed_git(p);
 901                 return retval;
 902         case OBJ_COMMIT:
 903                 strcpy(type, "commit");
 904                 break;
 905         case OBJ_TREE:
 906                 strcpy(type, "tree");
 907                 break;
 908         case OBJ_BLOB:
 909                 strcpy(type, "blob");
 910                 break;
 911         case OBJ_TAG:
 912                 strcpy(type, "tag");
 913                 break;
 914         default:
 915                 die("corrupted pack file %s containing object of kind %d",
 916                     p->pack_name, kind);
 917         }
 918         if (sizep)
 919                 *sizep = size;
 920         unuse_packed_git(p);
 921         return 0;
 922 }
 923
 924 /* forward declaration for a mutually recursive function */
 925 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 926
 927 static void *unpack_delta_entry(unsigned char *base_sha1,
 928                                 unsigned long delta_size,
 929                                 unsigned long left,
 930                                 char *type,
 931                                 unsigned long *sizep,
 932                                 struct packed_git *p)
 933 {
 934         struct pack_entry base_ent;
 935         void *data, *delta_data, *result, *base;
 936         unsigned long data_size, result_size, base_size;
 937         z_stream stream;
 938         int st;
 939
 940         if (left < 20)
 941                 die("truncated pack file");
 942         data = base_sha1 + 20;
 943         data_size = left - 20;
 944         delta_data = xmalloc(delta_size);
 945
 946         memset(&stream, 0, sizeof(stream));
 947
 948         stream.next_in = data;
 949         stream.avail_in = data_size;
 950         stream.next_out = delta_data;
 951         stream.avail_out = delta_size;
 952
 953         inflateInit(&stream);
 954         st = inflate(&stream, Z_FINISH);
 955         inflateEnd(&stream);
 956         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
 957                 die("delta data unpack failed");
 958
 959         /* The base entry _must_ be in the same pack */
 960         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 961                 die("failed to find delta-pack base object %s",
 962                     sha1_to_hex(base_sha1));
 963         base = unpack_entry_gently(&base_ent, type, &base_size);
 964         if (!base)
 965                 die("failed to read delta-pack base object %s",
 966                     sha1_to_hex(base_sha1));
 967         result = patch_delta(base, base_size,
 968                              delta_data, delta_size,
 969                              &result_size);
 970         if (!result)
 971                 die("failed to apply delta");
 972         free(delta_data);
 973         free(base);
 974         *sizep = result_size;
 975         return result;
 976 }
 977
 978 static void *unpack_non_delta_entry(unsigned char *data,
 979                                     unsigned long size,
 980                                     unsigned long left)
 981 {
 982         int st;
 983         z_stream stream;
 984         unsigned char *buffer;
 985
 986         buffer = xmalloc(size + 1);
 987         buffer[size] = 0;
 988         memset(&stream, 0, sizeof(stream));
 989         stream.next_in = data;
 990         stream.avail_in = left;
 991         stream.next_out = buffer;
 992         stream.avail_out = size;
 993
 994         inflateInit(&stream);
 995         st = inflate(&stream, Z_FINISH);
 996         inflateEnd(&stream);
 997         if ((st != Z_STREAM_END) || stream.total_out != size) {
 998                 free(buffer);
 999                 return NULL;
1000         }
1001
1002         return buffer;
1003 }
1004
1005 static void *unpack_entry(struct pack_entry *entry,
1006                           char *type, unsigned long *sizep)
1007 {
1008         struct packed_git *p = entry->p;
1009         void *retval;
1010
1011         if (use_packed_git(p))
1012                 die("cannot map packed file");
1013         retval = unpack_entry_gently(entry, type, sizep);
1014         unuse_packed_git(p);
1015         if (!retval)
1016                 die("corrupted pack file %s", p->pack_name);
1017         return retval;
1018 }
1019
1020 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1021 void *unpack_entry_gently(struct pack_entry *entry,
1022                           char *type, unsigned long *sizep)
1023 {
1024         struct packed_git *p = entry->p;
1025         unsigned long offset, size, left;
1026         unsigned char *pack;
1027         enum object_type kind;
1028         void *retval;
1029
1030         offset = unpack_object_header(p, entry->offset, &kind, &size);
1031         pack = p->pack_base + offset;
1032         left = p->pack_size - offset;
1033         switch (kind) {
1034         case OBJ_DELTA:
1035                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1036                 return retval;
1037         case OBJ_COMMIT:
1038                 strcpy(type, "commit");
1039                 break;
1040         case OBJ_TREE:
1041                 strcpy(type, "tree");
1042                 break;
1043         case OBJ_BLOB:
1044                 strcpy(type, "blob");
1045                 break;
1046         case OBJ_TAG:
1047                 strcpy(type, "tag");
1048                 break;
1049         default:
1050                 return NULL;
1051         }
1052         *sizep = size;
1053         retval = unpack_non_delta_entry(pack, size, left);
1054         return retval;
1055 }
1056
1057 int num_packed_objects(const struct packed_git *p)
1058 {
1059         /* See check_packed_git_idx() */
1060         return (p->index_size - 20 - 20 - 4*256) / 24;
1061 }
1062
1063 int nth_packed_object_sha1(const struct packed_git *p, int n,
1064                            unsigned char* sha1)
1065 {
1066         void *index = p->index_base + 256;
1067         if (n < 0 || num_packed_objects(p) <= n)
1068                 return -1;
1069         memcpy(sha1, (index + 24 * n + 4), 20);
1070         return 0;
1071 }
1072
1073 int find_pack_entry_one(const unsigned char *sha1,
1074                         struct pack_entry *e, struct packed_git *p)
1075 {
1076         unsigned int *level1_ofs = p->index_base;
1077         int hi = ntohl(level1_ofs[*sha1]);
1078         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1079         void *index = p->index_base + 256;
1080
1081         do {
1082                 int mi = (lo + hi) / 2;
1083                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1084                 if (!cmp) {
1085                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1086                         memcpy(e->sha1, sha1, 20);
1087                         e->p = p;
1088                         return 1;
1089                 }
1090                 if (cmp > 0)
1091                         hi = mi;
1092                 else
1093                         lo = mi+1;
1094         } while (lo < hi);
1095         return 0;
1096 }
1097
1098 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1099 {
1100         struct packed_git *p;
1101         prepare_packed_git();
1102
1103         for (p = packed_git; p; p = p->next) {
1104                 if (find_pack_entry_one(sha1, e, p))
1105                         return 1;
1106         }
1107         return 0;
1108 }
1109
1110 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1111                                   struct packed_git *packs)
1112 {
1113         struct packed_git *p;
1114         struct pack_entry e;
1115
1116         for (p = packs; p; p = p->next) {
1117                 if (find_pack_entry_one(sha1, &e, p))
1118                         return p;
1119         }
1120         return NULL;
1121
1122 }
1123
1124 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1125 {
1126         int status;
1127         unsigned long mapsize, size;
1128         void *map;
1129         z_stream stream;
1130         char hdr[128];
1131
1132         map = map_sha1_file_internal(sha1, &mapsize);
1133         if (!map) {
1134                 struct pack_entry e;
1135
1136                 if (!find_pack_entry(sha1, &e))
1137                         return error("unable to find %s", sha1_to_hex(sha1));
1138                 return packed_object_info(&e, type, sizep);
1139         }
1140         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1141                 status = error("unable to unpack %s header",
1142                                sha1_to_hex(sha1));
1143         if (parse_sha1_header(hdr, type, &size) < 0)
1144                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1145         else {
1146                 status = 0;
1147                 if (sizep)
1148                         *sizep = size;
1149         }
1150         inflateEnd(&stream);
1151         munmap(map, mapsize);
1152         return status;
1153 }
1154
1155 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1156 {
1157         struct pack_entry e;
1158
1159         if (!find_pack_entry(sha1, &e)) {
1160                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1161                 return NULL;
1162         }
1163         return unpack_entry(&e, type, size);
1164 }
1165
1166 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1167 {
1168         unsigned long mapsize;
1169         void *map, *buf;
1170         struct pack_entry e;
1171
1172         if (find_pack_entry(sha1, &e))
1173                 return read_packed_sha1(sha1, type, size);
1174         map = map_sha1_file_internal(sha1, &mapsize);
1175         if (map) {
1176                 buf = unpack_sha1_file(map, mapsize, type, size);
1177                 munmap(map, mapsize);
1178                 return buf;
1179         }
1180         return NULL;
1181 }
1182
1183 void *read_object_with_reference(const unsigned char *sha1,
1184                                  const char *required_type,
1185                                  unsigned long *size,
1186                                  unsigned char *actual_sha1_return)
1187 {
1188         char type[20];
1189         void *buffer;
1190         unsigned long isize;
1191         unsigned char actual_sha1[20];
1192
1193         memcpy(actual_sha1, sha1, 20);
1194         while (1) {
1195                 int ref_length = -1;
1196                 const char *ref_type = NULL;
1197
1198                 buffer = read_sha1_file(actual_sha1, type, &isize);
1199                 if (!buffer)
1200                         return NULL;
1201                 if (!strcmp(type, required_type)) {
1202                         *size = isize;
1203                         if (actual_sha1_return)
1204                                 memcpy(actual_sha1_return, actual_sha1, 20);
1205                         return buffer;
1206                 }
1207                 /* Handle references */
1208                 else if (!strcmp(type, "commit"))
1209                         ref_type = "tree ";
1210                 else if (!strcmp(type, "tag"))
1211                         ref_type = "object ";
1212                 else {
1213                         free(buffer);
1214                         return NULL;
1215                 }
1216                 ref_length = strlen(ref_type);
1217
1218                 if (memcmp(buffer, ref_type, ref_length) ||
1219                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1220                         free(buffer);
1221                         return NULL;
1222                 }
1223                 free(buffer);
1224                 /* Now we have the ID of the referred-to object in
1225                  * actual_sha1.  Check again. */
1226         }
1227 }
1228
1229 char *write_sha1_file_prepare(void *buf,
1230                               unsigned long len,
1231                               const char *type,
1232                               unsigned char *sha1,
1233                               unsigned char *hdr,
1234                               int *hdrlen)
1235 {
1236         SHA_CTX c;
1237
1238         /* Generate the header */
1239         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1240
1241         /* Sha1.. */
1242         SHA1_Init(&c);
1243         SHA1_Update(&c, hdr, *hdrlen);
1244         SHA1_Update(&c, buf, len);
1245         SHA1_Final(sha1, &c);
1246
1247         return sha1_file_name(sha1);
1248 }
1249
1250 /*
1251  * Link the tempfile to the final place, possibly creating the
1252  * last directory level as you do so.
1253  *
1254  * Returns the errno on failure, 0 on success.
1255  */
1256 static int link_temp_to_file(const char *tmpfile, char *filename)
1257 {
1258         int ret;
1259
1260         if (!link(tmpfile, filename))
1261                 return 0;
1262
1263         /*
1264          * Try to mkdir the last path component if that failed
1265          * with an ENOENT.
1266          *
1267          * Re-try the "link()" regardless of whether the mkdir
1268          * succeeds, since a race might mean that somebody
1269          * else succeeded.
1270          */
1271         ret = errno;
1272         if (ret == ENOENT) {
1273                 char *dir = strrchr(filename, '/');
1274                 if (dir) {
1275                         *dir = 0;
1276                         mkdir(filename, 0777);
1277                         if (adjust_shared_perm(filename))
1278                                 return -2;
1279                         *dir = '/';
1280                         if (!link(tmpfile, filename))
1281                                 return 0;
1282                         ret = errno;
1283                 }
1284         }
1285         return ret;
1286 }
1287
1288 /*
1289  * Move the just written object into its final resting place
1290  */
1291 int move_temp_to_file(const char *tmpfile, char *filename)
1292 {
1293         int ret = link_temp_to_file(tmpfile, filename);
1294
1295         /*
1296          * Coda hack - coda doesn't like cross-directory links,
1297          * so we fall back to a rename, which will mean that it
1298          * won't be able to check collisions, but that's not a
1299          * big deal.
1300          *
1301          * The same holds for FAT formatted media.
1302          *
1303          * When this succeeds, we just return 0. We have nothing
1304          * left to unlink.
1305          */
1306         if (ret && ret != EEXIST) {
1307                 if (!rename(tmpfile, filename))
1308                         return 0;
1309                 ret = errno;
1310         }
1311         unlink(tmpfile);
1312         if (ret) {
1313                 if (ret != EEXIST) {
1314                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1315                         return -1;
1316                 }
1317                 /* FIXME!!! Collision check here ? */
1318         }
1319
1320         return 0;
1321 }
1322
1323 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1324 {
1325         int size;
1326         unsigned char *compressed;
1327         z_stream stream;
1328         unsigned char sha1[20];
1329         char *filename;
1330         static char tmpfile[PATH_MAX];
1331         unsigned char hdr[50];
1332         int fd, hdrlen;
1333
1334         /* Normally if we have it in the pack then we do not bother writing
1335          * it out into .git/objects/??/?{38} file.
1336          */
1337         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1338         if (returnsha1)
1339                 memcpy(returnsha1, sha1, 20);
1340         if (has_sha1_file(sha1))
1341                 return 0;
1342         fd = open(filename, O_RDONLY);
1343         if (fd >= 0) {
1344                 /*
1345                  * FIXME!!! We might do collision checking here, but we'd
1346                  * need to uncompress the old file and check it. Later.
1347                  */
1348                 close(fd);
1349                 return 0;
1350         }
1351
1352         if (errno != ENOENT) {
1353                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1354                 return -1;
1355         }
1356
1357         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1358
1359         fd = mkstemp(tmpfile);
1360         if (fd < 0) {
1361                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1362                 return -1;
1363         }
1364
1365         /* Set it up */
1366         memset(&stream, 0, sizeof(stream));
1367         deflateInit(&stream, Z_BEST_COMPRESSION);
1368         size = deflateBound(&stream, len+hdrlen);
1369         compressed = xmalloc(size);
1370
1371         /* Compress it */
1372         stream.next_out = compressed;
1373         stream.avail_out = size;
1374
1375         /* First header.. */
1376         stream.next_in = hdr;
1377         stream.avail_in = hdrlen;
1378         while (deflate(&stream, 0) == Z_OK)
1379                 /* nothing */;
1380
1381         /* Then the data itself.. */
1382         stream.next_in = buf;
1383         stream.avail_in = len;
1384         while (deflate(&stream, Z_FINISH) == Z_OK)
1385                 /* nothing */;
1386         deflateEnd(&stream);
1387         size = stream.total_out;
1388
1389         if (write(fd, compressed, size) != size)
1390                 die("unable to write file");
1391         fchmod(fd, 0444);
1392         close(fd);
1393         free(compressed);
1394
1395         return move_temp_to_file(tmpfile, filename);
1396 }
1397
1398 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1399 {
1400         ssize_t size;
1401         unsigned long objsize;
1402         int posn = 0;
1403         void *map = map_sha1_file_internal(sha1, &objsize);
1404         void *buf = map;
1405         void *temp_obj = NULL;
1406         z_stream stream;
1407
1408         if (!buf) {
1409                 unsigned char *unpacked;
1410                 unsigned long len;
1411                 char type[20];
1412                 char hdr[50];
1413                 int hdrlen;
1414                 // need to unpack and recompress it by itself
1415                 unpacked = read_packed_sha1(sha1, type, &len);
1416
1417                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1418
1419                 /* Set it up */
1420                 memset(&stream, 0, sizeof(stream));
1421                 deflateInit(&stream, Z_BEST_COMPRESSION);
1422                 size = deflateBound(&stream, len + hdrlen);
1423                 temp_obj = buf = xmalloc(size);
1424
1425                 /* Compress it */
1426                 stream.next_out = buf;
1427                 stream.avail_out = size;
1428
1429                 /* First header.. */
1430                 stream.next_in = (void *)hdr;
1431                 stream.avail_in = hdrlen;
1432                 while (deflate(&stream, 0) == Z_OK)
1433                         /* nothing */;
1434
1435                 /* Then the data itself.. */
1436                 stream.next_in = unpacked;
1437                 stream.avail_in = len;
1438                 while (deflate(&stream, Z_FINISH) == Z_OK)
1439                         /* nothing */;
1440                 deflateEnd(&stream);
1441                 free(unpacked);
1442
1443                 objsize = stream.total_out;
1444         }
1445
1446         do {
1447                 size = write(fd, buf + posn, objsize - posn);
1448                 if (size <= 0) {
1449                         if (!size) {
1450                                 fprintf(stderr, "write closed\n");
1451                         } else {
1452                                 perror("write ");
1453                         }
1454                         return -1;
1455                 }
1456                 posn += size;
1457         } while (posn < objsize);
1458
1459         if (map)
1460                 munmap(map, objsize);
1461         if (temp_obj)
1462                 free(temp_obj);
1463
1464         return 0;
1465 }
1466
1467 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1468                        size_t bufsize, size_t *bufposn)
1469 {
1470         char tmpfile[PATH_MAX];
1471         int local;
1472         z_stream stream;
1473         unsigned char real_sha1[20];
1474         unsigned char discard[4096];
1475         int ret;
1476         SHA_CTX c;
1477
1478         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1479
1480         local = mkstemp(tmpfile);
1481         if (local < 0)
1482                 return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
1483
1484         memset(&stream, 0, sizeof(stream));
1485
1486         inflateInit(&stream);
1487
1488         SHA1_Init(&c);
1489
1490         do {
1491                 ssize_t size;
1492                 if (*bufposn) {
1493                         stream.avail_in = *bufposn;
1494                         stream.next_in = (unsigned char *) buffer;
1495                         do {
1496                                 stream.next_out = discard;
1497                                 stream.avail_out = sizeof(discard);
1498                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1499                                 SHA1_Update(&c, discard, sizeof(discard) -
1500                                             stream.avail_out);
1501                         } while (stream.avail_in && ret == Z_OK);
1502                         write(local, buffer, *bufposn - stream.avail_in);
1503                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1504                                 stream.avail_in);
1505                         *bufposn = stream.avail_in;
1506                         if (ret != Z_OK)
1507                                 break;
1508                 }
1509                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1510                 if (size <= 0) {
1511                         close(local);
1512                         unlink(tmpfile);
1513                         if (!size)
1514                                 return error("Connection closed?");
1515                         perror("Reading from connection");
1516                         return -1;
1517                 }
1518                 *bufposn += size;
1519         } while (1);
1520         inflateEnd(&stream);
1521
1522         close(local);
1523         SHA1_Final(real_sha1, &c);
1524         if (ret != Z_STREAM_END) {
1525                 unlink(tmpfile);
1526                 return error("File %s corrupted", sha1_to_hex(sha1));
1527         }
1528         if (memcmp(sha1, real_sha1, 20)) {
1529                 unlink(tmpfile);
1530                 return error("File %s has bad hash\n", sha1_to_hex(sha1));
1531         }
1532
1533         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1534 }
1535
1536 int has_pack_index(const unsigned char *sha1)
1537 {
1538         struct stat st;
1539         if (stat(sha1_pack_index_name(sha1), &st))
1540                 return 0;
1541         return 1;
1542 }
1543
1544 int has_pack_file(const unsigned char *sha1)
1545 {
1546         struct stat st;
1547         if (stat(sha1_pack_name(sha1), &st))
1548                 return 0;
1549         return 1;
1550 }
1551
1552 int has_sha1_pack(const unsigned char *sha1)
1553 {
1554         struct pack_entry e;
1555         return find_pack_entry(sha1, &e);
1556 }
1557
1558 int has_sha1_file(const unsigned char *sha1)
1559 {
1560         struct stat st;
1561         struct pack_entry e;
1562
1563         if (find_pack_entry(sha1, &e))
1564                 return 1;
1565         return find_sha1_file(sha1, &st) ? 1 : 0;
1566 }
1567
1568 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1569 {
1570         unsigned long size = 4096;
1571         char *buf = malloc(size);
1572         int iret, ret;
1573         unsigned long off = 0;
1574         unsigned char hdr[50];
1575         int hdrlen;
1576         do {
1577                 iret = read(fd, buf + off, size - off);
1578                 if (iret > 0) {
1579                         off += iret;
1580                         if (off == size) {
1581                                 size *= 2;
1582                                 buf = realloc(buf, size);
1583                         }
1584                 }
1585         } while (iret > 0);
1586         if (iret < 0) {
1587                 free(buf);
1588                 return -1;
1589         }
1590         if (!type)
1591                 type = "blob";
1592         if (write_object)
1593                 ret = write_sha1_file(buf, off, type, sha1);
1594         else {
1595                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1596                 ret = 0;
1597         }
1598         free(buf);
1599         return ret;
1600 }
1601
1602 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1603 {
1604         unsigned long size = st->st_size;
1605         void *buf;
1606         int ret;
1607         unsigned char hdr[50];
1608         int hdrlen;
1609
1610         buf = "";
1611         if (size)
1612                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1613         close(fd);
1614         if (buf == MAP_FAILED)
1615                 return -1;
1616
1617         if (!type)
1618                 type = "blob";
1619         if (write_object)
1620                 ret = write_sha1_file(buf, size, type, sha1);
1621         else {
1622                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1623                 ret = 0;
1624         }
1625         if (size)
1626                 munmap(buf, size);
1627         return ret;
1628 }
1629
1630 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1631 {
1632         int fd;
1633         char *target;
1634
1635         switch (st->st_mode & S_IFMT) {
1636         case S_IFREG:
1637                 fd = open(path, O_RDONLY);
1638                 if (fd < 0)
1639                         return error("open(\"%s\"): %s", path,
1640                                      strerror(errno));
1641                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1642                         return error("%s: failed to insert into database",
1643                                      path);
1644                 break;
1645         case S_IFLNK:
1646                 target = xmalloc(st->st_size+1);
1647                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1648                         char *errstr = strerror(errno);
1649                         free(target);
1650                         return error("readlink(\"%s\"): %s", path,
1651                                      errstr);
1652                 }
1653                 if (!write_object) {
1654                         unsigned char hdr[50];
1655                         int hdrlen;
1656                         write_sha1_file_prepare(target, st->st_size, "blob",
1657                                                 sha1, hdr, &hdrlen);
1658                 } else if (write_sha1_file(target, st->st_size, "blob", sha1))
1659                         return error("%s: failed to insert into database",
1660                                      path);
1661                 free(target);
1662                 break;
1663         default:
1664                 return error("%s: unsupported file type", path);
1665         }
1666         return 0;
1667 }