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 #include "blob.h"
  13 #include "commit.h"
  14 #include "tag.h"
  15 #include "tree.h"
  16
  17 #ifndef O_NOATIME
  18 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  19 #define O_NOATIME 01000000
  20 #else
  21 #define O_NOATIME 0
  22 #endif
  23 #endif
  24
  25 const unsigned char null_sha1[20];
  26
  27 static unsigned int sha1_file_open_flag = O_NOATIME;
  28
  29 static unsigned hexval(char c)
  30 {
  31         if (c >= '0' && c <= '9')
  32                 return c - '0';
  33         if (c >= 'a' && c <= 'f')
  34                 return c - 'a' + 10;
  35         if (c >= 'A' && c <= 'F')
  36                 return c - 'A' + 10;
  37         return ~0;
  38 }
  39
  40 int get_sha1_hex(const char *hex, unsigned char *sha1)
  41 {
  42         int i;
  43         for (i = 0; i < 20; i++) {
  44                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  45                 if (val & ~0xff)
  46                         return -1;
  47                 *sha1++ = val;
  48                 hex += 2;
  49         }
  50         return 0;
  51 }
  52
  53 int safe_create_leading_directories(char *path)
  54 {
  55         char *pos = path;
  56         struct stat st;
  57
  58         if (*pos == '/')
  59                 pos++;
  60
  61         while (pos) {
  62                 pos = strchr(pos, '/');
  63                 if (!pos)
  64                         break;
  65                 *pos = 0;
  66                 if (!stat(path, &st)) {
  67                         /* path exists */
  68                         if (!S_ISDIR(st.st_mode)) {
  69                                 *pos = '/';
  70                                 return -3;
  71                         }
  72                 }
  73                 else if (mkdir(path, 0777)) {
  74                         *pos = '/';
  75                         return -1;
  76                 }
  77                 else if (adjust_shared_perm(path)) {
  78                         *pos = '/';
  79                         return -2;
  80                 }
  81                 *pos++ = '/';
  82         }
  83         return 0;
  84 }
  85
  86 char * sha1_to_hex(const unsigned char *sha1)
  87 {
  88         static int bufno;
  89         static char hexbuffer[4][50];
  90         static const char hex[] = "0123456789abcdef";
  91         char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
  92         int i;
  93
  94         for (i = 0; i < 20; i++) {
  95                 unsigned int val = *sha1++;
  96                 *buf++ = hex[val >> 4];
  97                 *buf++ = hex[val & 0xf];
  98         }
  99         *buf = '\0';
 100
 101         return buffer;
 102 }
 103
 104 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 105 {
 106         int i;
 107         for (i = 0; i < 20; i++) {
 108                 static char hex[] = "0123456789abcdef";
 109                 unsigned int val = sha1[i];
 110                 char *pos = pathbuf + i*2 + (i > 0);
 111                 *pos++ = hex[val >> 4];
 112                 *pos = hex[val & 0xf];
 113         }
 114 }
 115
 116 /*
 117  * NOTE! This returns a statically allocated buffer, so you have to be
 118  * careful about using it. Do a "strdup()" if you need to save the
 119  * filename.
 120  *
 121  * Also note that this returns the location for creating.  Reading
 122  * SHA1 file can happen from any alternate directory listed in the
 123  * DB_ENVIRONMENT environment variable if it is not found in
 124  * the primary object database.
 125  */
 126 char *sha1_file_name(const unsigned char *sha1)
 127 {
 128         static char *name, *base;
 129         static const char *last_objdir;
 130         const char *sha1_file_directory = get_object_directory();
 131
 132         if (!last_objdir || strcmp(last_objdir, sha1_file_directory)) {
 133                 int len = strlen(sha1_file_directory);
 134                 if (base)
 135                         free(base);
 136                 base = xmalloc(len + 60);
 137                 memcpy(base, sha1_file_directory, len);
 138                 memset(base+len, 0, 60);
 139                 base[len] = '/';
 140                 base[len+3] = '/';
 141                 name = base + len + 1;
 142                 if (last_objdir)
 143                         free((char *) last_objdir);
 144                 last_objdir = strdup(sha1_file_directory);
 145         }
 146         fill_sha1_path(name, sha1);
 147         return base;
 148 }
 149
 150 char *sha1_pack_name(const unsigned char *sha1)
 151 {
 152         static const char hex[] = "0123456789abcdef";
 153         static char *name, *base, *buf;
 154         static const char *last_objdir;
 155         const char *sha1_file_directory = get_object_directory();
 156         int i;
 157
 158         if (!last_objdir || strcmp(last_objdir, sha1_file_directory)) {
 159                 int len = strlen(sha1_file_directory);
 160                 if (base)
 161                         free(base);
 162                 base = xmalloc(len + 60);
 163                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 164                 name = base + len + 11;
 165                 if (last_objdir)
 166                         free((char *) last_objdir);
 167                 last_objdir = strdup(sha1_file_directory);
 168         }
 169
 170         buf = name;
 171
 172         for (i = 0; i < 20; i++) {
 173                 unsigned int val = *sha1++;
 174                 *buf++ = hex[val >> 4];
 175                 *buf++ = hex[val & 0xf];
 176         }
 177
 178         return base;
 179 }
 180
 181 char *sha1_pack_index_name(const unsigned char *sha1)
 182 {
 183         static const char hex[] = "0123456789abcdef";
 184         static char *name, *base, *buf;
 185         static const char *last_objdir;
 186         const char *sha1_file_directory = get_object_directory();
 187         int i;
 188
 189         if (!last_objdir || strcmp(last_objdir, sha1_file_directory)) {
 190                 int len = strlen(sha1_file_directory);
 191                 if (base)
 192                         free(base);
 193                 base = xmalloc(len + 60);
 194                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 195                 name = base + len + 11;
 196                 if (last_objdir)
 197                         free((char *) last_objdir);
 198                 last_objdir = strdup(sha1_file_directory);
 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 static void read_info_alternates(const char * alternates, int depth);
 216
 217 /*
 218  * Prepare alternate object database registry.
 219  *
 220  * The variable alt_odb_list points at the list of struct
 221  * alternate_object_database.  The elements on this list come from
 222  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 223  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 224  * whose contents is similar to that environment variable but can be
 225  * LF separated.  Its base points at a statically allocated buffer that
 226  * contains "/the/directory/corresponding/to/.git/objects/...", while
 227  * its name points just after the slash at the end of ".git/objects/"
 228  * in the example above, and has enough space to hold 40-byte hex
 229  * SHA1, an extra slash for the first level indirection, and the
 230  * terminating NUL.
 231  */
 232 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 233 {
 234         struct stat st;
 235         const char *objdir = get_object_directory();
 236         struct alternate_object_database *ent;
 237         struct alternate_object_database *alt;
 238         /* 43 = 40-byte + 2 '/' + terminating NUL */
 239         int pfxlen = len;
 240         int entlen = pfxlen + 43;
 241         int base_len = -1;
 242
 243         if (*entry != '/' && relative_base) {
 244                 /* Relative alt-odb */
 245                 if (base_len < 0)
 246                         base_len = strlen(relative_base) + 1;
 247                 entlen += base_len;
 248                 pfxlen += base_len;
 249         }
 250         ent = xmalloc(sizeof(*ent) + entlen);
 251
 252         if (*entry != '/' && relative_base) {
 253                 memcpy(ent->base, relative_base, base_len - 1);
 254                 ent->base[base_len - 1] = '/';
 255                 memcpy(ent->base + base_len, entry, len);
 256         }
 257         else
 258                 memcpy(ent->base, entry, pfxlen);
 259
 260         ent->name = ent->base + pfxlen + 1;
 261         ent->base[pfxlen + 3] = '/';
 262         ent->base[pfxlen] = ent->base[entlen-1] = 0;
 263
 264         /* Detect cases where alternate disappeared */
 265         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 266                 error("object directory %s does not exist; "
 267                       "check .git/objects/info/alternates.",
 268                       ent->base);
 269                 free(ent);
 270                 return -1;
 271         }
 272
 273         /* Prevent the common mistake of listing the same
 274          * thing twice, or object directory itself.
 275          */
 276         for (alt = alt_odb_list; alt; alt = alt->next) {
 277                 if (!memcmp(ent->base, alt->base, pfxlen)) {
 278                         free(ent);
 279                         return -1;
 280                 }
 281         }
 282         if (!memcmp(ent->base, objdir, pfxlen)) {
 283                 free(ent);
 284                 return -1;
 285         }
 286
 287         /* add the alternate entry */
 288         *alt_odb_tail = ent;
 289         alt_odb_tail = &(ent->next);
 290         ent->next = NULL;
 291
 292         /* recursively add alternates */
 293         read_info_alternates(ent->base, depth + 1);
 294
 295         ent->base[pfxlen] = '/';
 296
 297         return 0;
 298 }
 299
 300 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 301                                  const char *relative_base, int depth)
 302 {
 303         const char *cp, *last;
 304
 305         if (depth > 5) {
 306                 error("%s: ignoring alternate object stores, nesting too deep.",
 307                                 relative_base);
 308                 return;
 309         }
 310
 311         last = alt;
 312         while (last < ep) {
 313                 cp = last;
 314                 if (cp < ep && *cp == '#') {
 315                         while (cp < ep && *cp != sep)
 316                                 cp++;
 317                         last = cp + 1;
 318                         continue;
 319                 }
 320                 while (cp < ep && *cp != sep)
 321                         cp++;
 322                 if (last != cp) {
 323                         if ((*last != '/') && depth) {
 324                                 error("%s: ignoring relative alternate object store %s",
 325                                                 relative_base, last);
 326                         } else {
 327                                 link_alt_odb_entry(last, cp - last,
 328                                                 relative_base, depth);
 329                         }
 330                 }
 331                 while (cp < ep && *cp == sep)
 332                         cp++;
 333                 last = cp;
 334         }
 335 }
 336
 337 static void read_info_alternates(const char * relative_base, int depth)
 338 {
 339         char *map;
 340         struct stat st;
 341         char path[PATH_MAX];
 342         int fd;
 343
 344         sprintf(path, "%s/info/alternates", relative_base);
 345         fd = open(path, O_RDONLY);
 346         if (fd < 0)
 347                 return;
 348         if (fstat(fd, &st) || (st.st_size == 0)) {
 349                 close(fd);
 350                 return;
 351         }
 352         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 353         close(fd);
 354         if (map == MAP_FAILED)
 355                 return;
 356
 357         link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 358
 359         munmap(map, st.st_size);
 360 }
 361
 362 void prepare_alt_odb(void)
 363 {
 364         const char *alt;
 365
 366         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 367         if (!alt) alt = "";
 368
 369         if (alt_odb_tail)
 370                 return;
 371         alt_odb_tail = &alt_odb_list;
 372         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 373
 374         read_info_alternates(get_object_directory(), 0);
 375 }
 376
 377 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 378 {
 379         char *name = sha1_file_name(sha1);
 380         struct alternate_object_database *alt;
 381
 382         if (!stat(name, st))
 383                 return name;
 384         prepare_alt_odb();
 385         for (alt = alt_odb_list; alt; alt = alt->next) {
 386                 name = alt->name;
 387                 fill_sha1_path(name, sha1);
 388                 if (!stat(alt->base, st))
 389                         return alt->base;
 390         }
 391         return NULL;
 392 }
 393
 394 #define PACK_MAX_SZ (1<<26)
 395 static int pack_used_ctr;
 396 static unsigned long pack_mapped;
 397 struct packed_git *packed_git;
 398
 399 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 400                                 void **idx_map_)
 401 {
 402         void *idx_map;
 403         unsigned int *index;
 404         unsigned long idx_size;
 405         int nr, i;
 406         int fd = open(path, O_RDONLY);
 407         struct stat st;
 408         if (fd < 0)
 409                 return -1;
 410         if (fstat(fd, &st)) {
 411                 close(fd);
 412                 return -1;
 413         }
 414         idx_size = st.st_size;
 415         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 416         close(fd);
 417         if (idx_map == MAP_FAILED)
 418                 return -1;
 419
 420         index = idx_map;
 421         *idx_map_ = idx_map;
 422         *idx_size_ = idx_size;
 423
 424         /* check index map */
 425         if (idx_size < 4*256 + 20 + 20)
 426                 return error("index file too small");
 427         nr = 0;
 428         for (i = 0; i < 256; i++) {
 429                 unsigned int n = ntohl(index[i]);
 430                 if (n < nr)
 431                         return error("non-monotonic index");
 432                 nr = n;
 433         }
 434
 435         /*
 436          * Total size:
 437          *  - 256 index entries 4 bytes each
 438          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 439          *  - 20-byte SHA1 of the packfile
 440          *  - 20-byte SHA1 file checksum
 441          */
 442         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 443                 return error("wrong index file size");
 444
 445         return 0;
 446 }
 447
 448 static int unuse_one_packed_git(void)
 449 {
 450         struct packed_git *p, *lru = NULL;
 451
 452         for (p = packed_git; p; p = p->next) {
 453                 if (p->pack_use_cnt || !p->pack_base)
 454                         continue;
 455                 if (!lru || p->pack_last_used < lru->pack_last_used)
 456                         lru = p;
 457         }
 458         if (!lru)
 459                 return 0;
 460         munmap(lru->pack_base, lru->pack_size);
 461         lru->pack_base = NULL;
 462         return 1;
 463 }
 464
 465 void unuse_packed_git(struct packed_git *p)
 466 {
 467         p->pack_use_cnt--;
 468 }
 469
 470 int use_packed_git(struct packed_git *p)
 471 {
 472         if (!p->pack_size) {
 473                 struct stat st;
 474                 /* We created the struct before we had the pack */
 475                 stat(p->pack_name, &st);
 476                 if (!S_ISREG(st.st_mode))
 477                         die("packfile %s not a regular file", p->pack_name);
 478                 p->pack_size = st.st_size;
 479         }
 480         if (!p->pack_base) {
 481                 int fd;
 482                 struct stat st;
 483                 void *map;
 484                 struct pack_header *hdr;
 485
 486                 pack_mapped += p->pack_size;
 487                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 488                         ; /* nothing */
 489                 fd = open(p->pack_name, O_RDONLY);
 490                 if (fd < 0)
 491                         die("packfile %s cannot be opened", p->pack_name);
 492                 if (fstat(fd, &st)) {
 493                         close(fd);
 494                         die("packfile %s cannot be opened", p->pack_name);
 495                 }
 496                 if (st.st_size != p->pack_size)
 497                         die("packfile %s size mismatch.", p->pack_name);
 498                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 499                 close(fd);
 500                 if (map == MAP_FAILED)
 501                         die("packfile %s cannot be mapped.", p->pack_name);
 502                 p->pack_base = map;
 503
 504                 /* Check if we understand this pack file.  If we don't we're
 505                  * likely too old to handle it.
 506                  */
 507                 hdr = map;
 508                 if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 509                         die("packfile %s isn't actually a pack.", p->pack_name);
 510                 if (!pack_version_ok(hdr->hdr_version))
 511                         die("packfile %s is version %i and not supported"
 512                                 " (try upgrading GIT to a newer version)",
 513                                 p->pack_name, ntohl(hdr->hdr_version));
 514
 515                 /* Check if the pack file matches with the index file.
 516                  * this is cheap.
 517                  */
 518                 if (hashcmp((unsigned char *)(p->index_base) +
 519                             p->index_size - 40,
 520                             (unsigned char *)p->pack_base +
 521                             p->pack_size - 20)) {
 522                         die("packfile %s does not match index.", p->pack_name);
 523                 }
 524         }
 525         p->pack_last_used = pack_used_ctr++;
 526         p->pack_use_cnt++;
 527         return 0;
 528 }
 529
 530 struct packed_git *add_packed_git(char *path, int path_len, int local)
 531 {
 532         struct stat st;
 533         struct packed_git *p;
 534         unsigned long idx_size;
 535         void *idx_map;
 536         unsigned char sha1[20];
 537
 538         if (check_packed_git_idx(path, &idx_size, &idx_map))
 539                 return NULL;
 540
 541         /* do we have a corresponding .pack file? */
 542         strcpy(path + path_len - 4, ".pack");
 543         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 544                 munmap(idx_map, idx_size);
 545                 return NULL;
 546         }
 547         /* ok, it looks sane as far as we can check without
 548          * actually mapping the pack file.
 549          */
 550         p = xmalloc(sizeof(*p) + path_len + 2);
 551         strcpy(p->pack_name, path);
 552         p->index_size = idx_size;
 553         p->pack_size = st.st_size;
 554         p->index_base = idx_map;
 555         p->next = NULL;
 556         p->pack_base = NULL;
 557         p->pack_last_used = 0;
 558         p->pack_use_cnt = 0;
 559         p->pack_local = local;
 560         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 561                 hashcpy(p->sha1, sha1);
 562         return p;
 563 }
 564
 565 struct packed_git *parse_pack_index(unsigned char *sha1)
 566 {
 567         char *path = sha1_pack_index_name(sha1);
 568         return parse_pack_index_file(sha1, path);
 569 }
 570
 571 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 572 {
 573         struct packed_git *p;
 574         unsigned long idx_size;
 575         void *idx_map;
 576         char *path;
 577
 578         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 579                 return NULL;
 580
 581         path = sha1_pack_name(sha1);
 582
 583         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 584         strcpy(p->pack_name, path);
 585         p->index_size = idx_size;
 586         p->pack_size = 0;
 587         p->index_base = idx_map;
 588         p->next = NULL;
 589         p->pack_base = NULL;
 590         p->pack_last_used = 0;
 591         p->pack_use_cnt = 0;
 592         hashcpy(p->sha1, sha1);
 593         return p;
 594 }
 595
 596 void install_packed_git(struct packed_git *pack)
 597 {
 598         pack->next = packed_git;
 599         packed_git = pack;
 600 }
 601
 602 static void prepare_packed_git_one(char *objdir, int local)
 603 {
 604         char path[PATH_MAX];
 605         int len;
 606         DIR *dir;
 607         struct dirent *de;
 608
 609         sprintf(path, "%s/pack", objdir);
 610         len = strlen(path);
 611         dir = opendir(path);
 612         if (!dir) {
 613                 if (errno != ENOENT)
 614                         error("unable to open object pack directory: %s: %s",
 615                               path, strerror(errno));
 616                 return;
 617         }
 618         path[len++] = '/';
 619         while ((de = readdir(dir)) != NULL) {
 620                 int namelen = strlen(de->d_name);
 621                 struct packed_git *p;
 622
 623                 if (!has_extension(de->d_name, ".idx"))
 624                         continue;
 625
 626                 /* we have .idx.  Is it a file we can map? */
 627                 strcpy(path + len, de->d_name);
 628                 for (p = packed_git; p; p = p->next) {
 629                         if (!memcmp(path, p->pack_name, len + namelen - 4))
 630                                 break;
 631                 }
 632                 if (p)
 633                         continue;
 634                 p = add_packed_git(path, len + namelen, local);
 635                 if (!p)
 636                         continue;
 637                 p->next = packed_git;
 638                 packed_git = p;
 639         }
 640         closedir(dir);
 641 }
 642
 643 static int prepare_packed_git_run_once = 0;
 644 void prepare_packed_git(void)
 645 {
 646         struct alternate_object_database *alt;
 647
 648         if (prepare_packed_git_run_once)
 649                 return;
 650         prepare_packed_git_one(get_object_directory(), 1);
 651         prepare_alt_odb();
 652         for (alt = alt_odb_list; alt; alt = alt->next) {
 653                 alt->name[-1] = 0;
 654                 prepare_packed_git_one(alt->base, 0);
 655                 alt->name[-1] = '/';
 656         }
 657         prepare_packed_git_run_once = 1;
 658 }
 659
 660 static void reprepare_packed_git(void)
 661 {
 662         prepare_packed_git_run_once = 0;
 663         prepare_packed_git();
 664 }
 665
 666 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 667 {
 668         char header[100];
 669         unsigned char real_sha1[20];
 670         SHA_CTX c;
 671
 672         SHA1_Init(&c);
 673         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 674         SHA1_Update(&c, map, size);
 675         SHA1_Final(real_sha1, &c);
 676         return hashcmp(sha1, real_sha1) ? -1 : 0;
 677 }
 678
 679 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 680 {
 681         struct stat st;
 682         void *map;
 683         int fd;
 684         char *filename = find_sha1_file(sha1, &st);
 685
 686         if (!filename) {
 687                 return NULL;
 688         }
 689
 690         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 691         if (fd < 0) {
 692                 /* See if it works without O_NOATIME */
 693                 switch (sha1_file_open_flag) {
 694                 default:
 695                         fd = open(filename, O_RDONLY);
 696                         if (fd >= 0)
 697                                 break;
 698                 /* Fallthrough */
 699                 case 0:
 700                         return NULL;
 701                 }
 702
 703                 /* If it failed once, it will probably fail again.
 704                  * Stop using O_NOATIME
 705                  */
 706                 sha1_file_open_flag = 0;
 707         }
 708         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 709         close(fd);
 710         if (map == MAP_FAILED)
 711                 return NULL;
 712         *size = st.st_size;
 713         return map;
 714 }
 715
 716 int legacy_loose_object(unsigned char *map)
 717 {
 718         unsigned int word;
 719
 720         /*
 721          * Is it a zlib-compressed buffer? If so, the first byte
 722          * must be 0x78 (15-bit window size, deflated), and the
 723          * first 16-bit word is evenly divisible by 31
 724          */
 725         word = (map[0] << 8) + map[1];
 726         if (map[0] == 0x78 && !(word % 31))
 727                 return 1;
 728         else
 729                 return 0;
 730 }
 731
 732 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 733 {
 734         unsigned char c;
 735         unsigned int bits;
 736         unsigned long size;
 737         static const char *typename[8] = {
 738                 NULL,   /* OBJ_EXT */
 739                 "commit", "tree", "blob", "tag",
 740                 NULL, NULL, NULL
 741         };
 742         const char *type;
 743
 744         /* Get the data stream */
 745         memset(stream, 0, sizeof(*stream));
 746         stream->next_in = map;
 747         stream->avail_in = mapsize;
 748         stream->next_out = buffer;
 749         stream->avail_out = bufsiz;
 750
 751         if (legacy_loose_object(map)) {
 752                 inflateInit(stream);
 753                 return inflate(stream, 0);
 754         }
 755
 756         c = *map++;
 757         mapsize--;
 758         type = typename[(c >> 4) & 7];
 759         if (!type)
 760                 return -1;
 761
 762         bits = 4;
 763         size = c & 0xf;
 764         while ((c & 0x80)) {
 765                 if (bits >= 8*sizeof(long))
 766                         return -1;
 767                 c = *map++;
 768                 size += (c & 0x7f) << bits;
 769                 bits += 7;
 770                 mapsize--;
 771         }
 772
 773         /* Set up the stream for the rest.. */
 774         stream->next_in = map;
 775         stream->avail_in = mapsize;
 776         inflateInit(stream);
 777
 778         /* And generate the fake traditional header */
 779         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", type, size);
 780         return 0;
 781 }
 782
 783 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 784 {
 785         int bytes = strlen(buffer) + 1;
 786         unsigned char *buf = xmalloc(1+size);
 787         unsigned long n;
 788
 789         n = stream->total_out - bytes;
 790         if (n > size)
 791                 n = size;
 792         memcpy(buf, (char *) buffer + bytes, n);
 793         bytes = n;
 794         if (bytes < size) {
 795                 stream->next_out = buf + bytes;
 796                 stream->avail_out = size - bytes;
 797                 while (inflate(stream, Z_FINISH) == Z_OK)
 798                         /* nothing */;
 799         }
 800         buf[size] = 0;
 801         inflateEnd(stream);
 802         return buf;
 803 }
 804
 805 /*
 806  * We used to just use "sscanf()", but that's actually way
 807  * too permissive for what we want to check. So do an anal
 808  * object header parse by hand.
 809  */
 810 static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 811 {
 812         int i;
 813         unsigned long size;
 814
 815         /*
 816          * The type can be at most ten bytes (including the
 817          * terminating '\0' that we add), and is followed by
 818          * a space.
 819          */
 820         i = 10;
 821         for (;;) {
 822                 char c = *hdr++;
 823                 if (c == ' ')
 824                         break;
 825                 if (!--i)
 826                         return -1;
 827                 *type++ = c;
 828         }
 829         *type = 0;
 830
 831         /*
 832          * The length must follow immediately, and be in canonical
 833          * decimal format (ie "010" is not valid).
 834          */
 835         size = *hdr++ - '0';
 836         if (size > 9)
 837                 return -1;
 838         if (size) {
 839                 for (;;) {
 840                         unsigned long c = *hdr - '0';
 841                         if (c > 9)
 842                                 break;
 843                         hdr++;
 844                         size = size * 10 + c;
 845                 }
 846         }
 847         *sizep = size;
 848
 849         /*
 850          * The length must be followed by a zero byte
 851          */
 852         return *hdr ? -1 : 0;
 853 }
 854
 855 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 856 {
 857         int ret;
 858         z_stream stream;
 859         char hdr[8192];
 860
 861         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 862         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 863                 return NULL;
 864
 865         return unpack_sha1_rest(&stream, hdr, *size);
 866 }
 867
 868 /* forward declaration for a mutually recursive function */
 869 static int packed_object_info(struct pack_entry *entry,
 870                               char *type, unsigned long *sizep);
 871
 872 static int packed_delta_info(unsigned char *base_sha1,
 873                              unsigned long delta_size,
 874                              unsigned long left,
 875                              char *type,
 876                              unsigned long *sizep,
 877                              struct packed_git *p)
 878 {
 879         struct pack_entry base_ent;
 880
 881         if (left < 20)
 882                 die("truncated pack file");
 883
 884         /* The base entry _must_ be in the same pack */
 885         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 886                 die("failed to find delta-pack base object %s",
 887                     sha1_to_hex(base_sha1));
 888
 889         /* We choose to only get the type of the base object and
 890          * ignore potentially corrupt pack file that expects the delta
 891          * based on a base with a wrong size.  This saves tons of
 892          * inflate() calls.
 893          */
 894
 895         if (packed_object_info(&base_ent, type, NULL))
 896                 die("cannot get info for delta-pack base");
 897
 898         if (sizep) {
 899                 const unsigned char *data;
 900                 unsigned char delta_head[64];
 901                 unsigned long result_size;
 902                 z_stream stream;
 903                 int st;
 904
 905                 memset(&stream, 0, sizeof(stream));
 906
 907                 data = stream.next_in = base_sha1 + 20;
 908                 stream.avail_in = left - 20;
 909                 stream.next_out = delta_head;
 910                 stream.avail_out = sizeof(delta_head);
 911
 912                 inflateInit(&stream);
 913                 st = inflate(&stream, Z_FINISH);
 914                 inflateEnd(&stream);
 915                 if ((st != Z_STREAM_END) &&
 916                     stream.total_out != sizeof(delta_head))
 917                         die("delta data unpack-initial failed");
 918
 919                 /* Examine the initial part of the delta to figure out
 920                  * the result size.
 921                  */
 922                 data = delta_head;
 923
 924                 /* ignore base size */
 925                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 926
 927                 /* Read the result size */
 928                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 929                 *sizep = result_size;
 930         }
 931         return 0;
 932 }
 933
 934 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 935         enum object_type *type, unsigned long *sizep)
 936 {
 937         unsigned shift;
 938         unsigned char c;
 939         unsigned long size;
 940
 941         if (offset >= p->pack_size)
 942                 die("object offset outside of pack file");
 943         c = *((unsigned char *)p->pack_base + offset++);
 944         *type = (c >> 4) & 7;
 945         size = c & 15;
 946         shift = 4;
 947         while (c & 0x80) {
 948                 if (offset >= p->pack_size)
 949                         die("object offset outside of pack file");
 950                 c = *((unsigned char *)p->pack_base + offset++);
 951                 size += (c & 0x7f) << shift;
 952                 shift += 7;
 953         }
 954         *sizep = size;
 955         return offset;
 956 }
 957
 958 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 959                            unsigned char *base, unsigned long *sizep,
 960                            enum object_type *kindp)
 961 {
 962         unsigned long ptr;
 963         int status = -1;
 964
 965         use_packed_git(p);
 966         ptr = offset;
 967         ptr = unpack_object_header(p, ptr, kindp, sizep);
 968         if (*kindp != OBJ_DELTA)
 969                 goto done;
 970         hashcpy(base, (unsigned char *) p->pack_base + ptr);
 971         status = 0;
 972  done:
 973         unuse_packed_git(p);
 974         return status;
 975 }
 976
 977 void packed_object_info_detail(struct pack_entry *e,
 978                                char *type,
 979                                unsigned long *size,
 980                                unsigned long *store_size,
 981                                unsigned int *delta_chain_length,
 982                                unsigned char *base_sha1)
 983 {
 984         struct packed_git *p = e->p;
 985         unsigned long offset;
 986         unsigned char *pack;
 987         enum object_type kind;
 988
 989         offset = unpack_object_header(p, e->offset, &kind, size);
 990         pack = (unsigned char *) p->pack_base + offset;
 991         if (kind != OBJ_DELTA)
 992                 *delta_chain_length = 0;
 993         else {
 994                 unsigned int chain_length = 0;
 995                 if (p->pack_size <= offset + 20)
 996                         die("pack file %s records an incomplete delta base",
 997                             p->pack_name);
 998                 hashcpy(base_sha1, pack);
 999                 do {
1000                         struct pack_entry base_ent;
1001                         unsigned long junk;
1002
1003                         find_pack_entry_one(pack, &base_ent, p);
1004                         offset = unpack_object_header(p, base_ent.offset,
1005                                                       &kind, &junk);
1006                         pack = (unsigned char *) p->pack_base + offset;
1007                         chain_length++;
1008                 } while (kind == OBJ_DELTA);
1009                 *delta_chain_length = chain_length;
1010         }
1011         switch (kind) {
1012         case OBJ_COMMIT:
1013         case OBJ_TREE:
1014         case OBJ_BLOB:
1015         case OBJ_TAG:
1016                 strcpy(type, type_names[kind]);
1017                 break;
1018         default:
1019                 die("corrupted pack file %s containing object of kind %d",
1020                     p->pack_name, kind);
1021         }
1022         *store_size = 0; /* notyet */
1023 }
1024
1025 static int packed_object_info(struct pack_entry *entry,
1026                               char *type, unsigned long *sizep)
1027 {
1028         struct packed_git *p = entry->p;
1029         unsigned long offset, size, left;
1030         unsigned char *pack;
1031         enum object_type kind;
1032         int retval;
1033
1034         if (use_packed_git(p))
1035                 die("cannot map packed file");
1036
1037         offset = unpack_object_header(p, entry->offset, &kind, &size);
1038         pack = (unsigned char *) p->pack_base + offset;
1039         left = p->pack_size - offset;
1040
1041         switch (kind) {
1042         case OBJ_DELTA:
1043                 retval = packed_delta_info(pack, size, left, type, sizep, p);
1044                 unuse_packed_git(p);
1045                 return retval;
1046         case OBJ_COMMIT:
1047         case OBJ_TREE:
1048         case OBJ_BLOB:
1049         case OBJ_TAG:
1050                 strcpy(type, type_names[kind]);
1051                 break;
1052         default:
1053                 die("corrupted pack file %s containing object of kind %d",
1054                     p->pack_name, kind);
1055         }
1056         if (sizep)
1057                 *sizep = size;
1058         unuse_packed_git(p);
1059         return 0;
1060 }
1061
1062 static void *unpack_compressed_entry(struct packed_git *p,
1063                                     unsigned long offset,
1064                                     unsigned long size)
1065 {
1066         int st;
1067         z_stream stream;
1068         unsigned char *buffer;
1069
1070         buffer = xmalloc(size + 1);
1071         buffer[size] = 0;
1072         memset(&stream, 0, sizeof(stream));
1073         stream.next_in = (unsigned char*)p->pack_base + offset;
1074         stream.avail_in = p->pack_size - offset;
1075         stream.next_out = buffer;
1076         stream.avail_out = size;
1077
1078         inflateInit(&stream);
1079         st = inflate(&stream, Z_FINISH);
1080         inflateEnd(&stream);
1081         if ((st != Z_STREAM_END) || stream.total_out != size) {
1082                 free(buffer);
1083                 return NULL;
1084         }
1085
1086         return buffer;
1087 }
1088
1089 static void *unpack_delta_entry(struct packed_git *p,
1090                                 unsigned long offset,
1091                                 unsigned long delta_size,
1092                                 char *type,
1093                                 unsigned long *sizep)
1094 {
1095         struct pack_entry base_ent;
1096         void *delta_data, *result, *base;
1097         unsigned long result_size, base_size;
1098         unsigned char* base_sha1;
1099
1100         if ((offset + 20) >= p->pack_size)
1101                 die("truncated pack file");
1102
1103         /* The base entry _must_ be in the same pack */
1104         base_sha1 = (unsigned char*)p->pack_base + offset;
1105         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1106                 die("failed to find delta-pack base object %s",
1107                     sha1_to_hex(base_sha1));
1108         base = unpack_entry_gently(&base_ent, type, &base_size);
1109         if (!base)
1110                 die("failed to read delta-pack base object %s",
1111                     sha1_to_hex(base_sha1));
1112
1113         delta_data = unpack_compressed_entry(p, offset + 20, delta_size);
1114         result = patch_delta(base, base_size,
1115                              delta_data, delta_size,
1116                              &result_size);
1117         if (!result)
1118                 die("failed to apply delta");
1119         free(delta_data);
1120         free(base);
1121         *sizep = result_size;
1122         return result;
1123 }
1124
1125 static void *unpack_entry(struct pack_entry *entry,
1126                           char *type, unsigned long *sizep)
1127 {
1128         struct packed_git *p = entry->p;
1129         void *retval;
1130
1131         if (use_packed_git(p))
1132                 die("cannot map packed file");
1133         retval = unpack_entry_gently(entry, type, sizep);
1134         unuse_packed_git(p);
1135         if (!retval)
1136                 die("corrupted pack file %s", p->pack_name);
1137         return retval;
1138 }
1139
1140 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1141 void *unpack_entry_gently(struct pack_entry *entry,
1142                           char *type, unsigned long *sizep)
1143 {
1144         struct packed_git *p = entry->p;
1145         unsigned long offset, size;
1146         enum object_type kind;
1147
1148         offset = unpack_object_header(p, entry->offset, &kind, &size);
1149         switch (kind) {
1150         case OBJ_DELTA:
1151                 return unpack_delta_entry(p, offset, size, type, sizep);
1152         case OBJ_COMMIT:
1153         case OBJ_TREE:
1154         case OBJ_BLOB:
1155         case OBJ_TAG:
1156                 strcpy(type, type_names[kind]);
1157                 *sizep = size;
1158                 return unpack_compressed_entry(p, offset, size);
1159         default:
1160                 return NULL;
1161         }
1162 }
1163
1164 int num_packed_objects(const struct packed_git *p)
1165 {
1166         /* See check_packed_git_idx() */
1167         return (p->index_size - 20 - 20 - 4*256) / 24;
1168 }
1169
1170 int nth_packed_object_sha1(const struct packed_git *p, int n,
1171                            unsigned char* sha1)
1172 {
1173         void *index = p->index_base + 256;
1174         if (n < 0 || num_packed_objects(p) <= n)
1175                 return -1;
1176         hashcpy(sha1, (unsigned char *) index + (24 * n) + 4);
1177         return 0;
1178 }
1179
1180 int find_pack_entry_one(const unsigned char *sha1,
1181                         struct pack_entry *e, struct packed_git *p)
1182 {
1183         unsigned int *level1_ofs = p->index_base;
1184         int hi = ntohl(level1_ofs[*sha1]);
1185         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1186         void *index = p->index_base + 256;
1187
1188         do {
1189                 int mi = (lo + hi) / 2;
1190                 int cmp = hashcmp((unsigned char *)index + (24 * mi) + 4, sha1);
1191                 if (!cmp) {
1192                         e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1193                         hashcpy(e->sha1, sha1);
1194                         e->p = p;
1195                         return 1;
1196                 }
1197                 if (cmp > 0)
1198                         hi = mi;
1199                 else
1200                         lo = mi+1;
1201         } while (lo < hi);
1202         return 0;
1203 }
1204
1205 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1206 {
1207         struct packed_git *p;
1208         prepare_packed_git();
1209
1210         for (p = packed_git; p; p = p->next) {
1211                 if (find_pack_entry_one(sha1, e, p))
1212                         return 1;
1213         }
1214         return 0;
1215 }
1216
1217 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1218                                   struct packed_git *packs)
1219 {
1220         struct packed_git *p;
1221         struct pack_entry e;
1222
1223         for (p = packs; p; p = p->next) {
1224                 if (find_pack_entry_one(sha1, &e, p))
1225                         return p;
1226         }
1227         return NULL;
1228
1229 }
1230
1231 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1232 {
1233         int status;
1234         unsigned long mapsize, size;
1235         void *map;
1236         z_stream stream;
1237         char hdr[128];
1238
1239         map = map_sha1_file(sha1, &mapsize);
1240         if (!map) {
1241                 struct pack_entry e;
1242
1243                 if (find_pack_entry(sha1, &e))
1244                         return packed_object_info(&e, type, sizep);
1245                 reprepare_packed_git();
1246                 if (find_pack_entry(sha1, &e))
1247                         return packed_object_info(&e, type, sizep);
1248                 return error("unable to find %s", sha1_to_hex(sha1));
1249         }
1250         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1251                 status = error("unable to unpack %s header",
1252                                sha1_to_hex(sha1));
1253         if (parse_sha1_header(hdr, type, &size) < 0)
1254                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1255         else {
1256                 status = 0;
1257                 if (sizep)
1258                         *sizep = size;
1259         }
1260         inflateEnd(&stream);
1261         munmap(map, mapsize);
1262         return status;
1263 }
1264
1265 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1266 {
1267         struct pack_entry e;
1268
1269         if (!find_pack_entry(sha1, &e)) {
1270                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1271                 return NULL;
1272         }
1273         return unpack_entry(&e, type, size);
1274 }
1275
1276 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1277 {
1278         unsigned long mapsize;
1279         void *map, *buf;
1280         struct pack_entry e;
1281
1282         if (find_pack_entry(sha1, &e))
1283                 return read_packed_sha1(sha1, type, size);
1284         map = map_sha1_file(sha1, &mapsize);
1285         if (map) {
1286                 buf = unpack_sha1_file(map, mapsize, type, size);
1287                 munmap(map, mapsize);
1288                 return buf;
1289         }
1290         reprepare_packed_git();
1291         if (find_pack_entry(sha1, &e))
1292                 return read_packed_sha1(sha1, type, size);
1293         return NULL;
1294 }
1295
1296 void *read_object_with_reference(const unsigned char *sha1,
1297                                  const char *required_type,
1298                                  unsigned long *size,
1299                                  unsigned char *actual_sha1_return)
1300 {
1301         char type[20];
1302         void *buffer;
1303         unsigned long isize;
1304         unsigned char actual_sha1[20];
1305
1306         hashcpy(actual_sha1, sha1);
1307         while (1) {
1308                 int ref_length = -1;
1309                 const char *ref_type = NULL;
1310
1311                 buffer = read_sha1_file(actual_sha1, type, &isize);
1312                 if (!buffer)
1313                         return NULL;
1314                 if (!strcmp(type, required_type)) {
1315                         *size = isize;
1316                         if (actual_sha1_return)
1317                                 hashcpy(actual_sha1_return, actual_sha1);
1318                         return buffer;
1319                 }
1320                 /* Handle references */
1321                 else if (!strcmp(type, commit_type))
1322                         ref_type = "tree ";
1323                 else if (!strcmp(type, tag_type))
1324                         ref_type = "object ";
1325                 else {
1326                         free(buffer);
1327                         return NULL;
1328                 }
1329                 ref_length = strlen(ref_type);
1330
1331                 if (memcmp(buffer, ref_type, ref_length) ||
1332                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1333                         free(buffer);
1334                         return NULL;
1335                 }
1336                 free(buffer);
1337                 /* Now we have the ID of the referred-to object in
1338                  * actual_sha1.  Check again. */
1339         }
1340 }
1341
1342 char *write_sha1_file_prepare(void *buf,
1343                               unsigned long len,
1344                               const char *type,
1345                               unsigned char *sha1,
1346                               unsigned char *hdr,
1347                               int *hdrlen)
1348 {
1349         SHA_CTX c;
1350
1351         /* Generate the header */
1352         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1353
1354         /* Sha1.. */
1355         SHA1_Init(&c);
1356         SHA1_Update(&c, hdr, *hdrlen);
1357         SHA1_Update(&c, buf, len);
1358         SHA1_Final(sha1, &c);
1359
1360         return sha1_file_name(sha1);
1361 }
1362
1363 /*
1364  * Link the tempfile to the final place, possibly creating the
1365  * last directory level as you do so.
1366  *
1367  * Returns the errno on failure, 0 on success.
1368  */
1369 static int link_temp_to_file(const char *tmpfile, char *filename)
1370 {
1371         int ret;
1372         char *dir;
1373
1374         if (!link(tmpfile, filename))
1375                 return 0;
1376
1377         /*
1378          * Try to mkdir the last path component if that failed.
1379          *
1380          * Re-try the "link()" regardless of whether the mkdir
1381          * succeeds, since a race might mean that somebody
1382          * else succeeded.
1383          */
1384         ret = errno;
1385         dir = strrchr(filename, '/');
1386         if (dir) {
1387                 *dir = 0;
1388                 mkdir(filename, 0777);
1389                 if (adjust_shared_perm(filename))
1390                         return -2;
1391                 *dir = '/';
1392                 if (!link(tmpfile, filename))
1393                         return 0;
1394                 ret = errno;
1395         }
1396         return ret;
1397 }
1398
1399 /*
1400  * Move the just written object into its final resting place
1401  */
1402 int move_temp_to_file(const char *tmpfile, char *filename)
1403 {
1404         int ret = link_temp_to_file(tmpfile, filename);
1405
1406         /*
1407          * Coda hack - coda doesn't like cross-directory links,
1408          * so we fall back to a rename, which will mean that it
1409          * won't be able to check collisions, but that's not a
1410          * big deal.
1411          *
1412          * The same holds for FAT formatted media.
1413          *
1414          * When this succeeds, we just return 0. We have nothing
1415          * left to unlink.
1416          */
1417         if (ret && ret != EEXIST) {
1418                 if (!rename(tmpfile, filename))
1419                         return 0;
1420                 ret = errno;
1421         }
1422         unlink(tmpfile);
1423         if (ret) {
1424                 if (ret != EEXIST) {
1425                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1426                         return -1;
1427                 }
1428                 /* FIXME!!! Collision check here ? */
1429         }
1430
1431         return 0;
1432 }
1433
1434 static int write_buffer(int fd, const void *buf, size_t len)
1435 {
1436         while (len) {
1437                 ssize_t size;
1438
1439                 size = write(fd, buf, len);
1440                 if (!size)
1441                         return error("file write: disk full");
1442                 if (size < 0) {
1443                         if (errno == EINTR || errno == EAGAIN)
1444                                 continue;
1445                         return error("file write error (%s)", strerror(errno));
1446                 }
1447                 len -= size;
1448                 buf = (char *) buf + size;
1449         }
1450         return 0;
1451 }
1452
1453 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1454 {
1455         int hdr_len;
1456         unsigned char c;
1457
1458         c = (type << 4) | (len & 15);
1459         len >>= 4;
1460         hdr_len = 1;
1461         while (len) {
1462                 *hdr++ = c | 0x80;
1463                 hdr_len++;
1464                 c = (len & 0x7f);
1465                 len >>= 7;
1466         }
1467         *hdr = c;
1468         return hdr_len;
1469 }
1470
1471 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1472 {
1473         int obj_type, hdr;
1474
1475         if (use_legacy_headers) {
1476                 while (deflate(stream, 0) == Z_OK)
1477                         /* nothing */;
1478                 return;
1479         }
1480         if (!strcmp(type, blob_type))
1481                 obj_type = OBJ_BLOB;
1482         else if (!strcmp(type, tree_type))
1483                 obj_type = OBJ_TREE;
1484         else if (!strcmp(type, commit_type))
1485                 obj_type = OBJ_COMMIT;
1486         else if (!strcmp(type, tag_type))
1487                 obj_type = OBJ_TAG;
1488         else
1489                 die("trying to generate bogus object of type '%s'", type);
1490         hdr = write_binary_header(stream->next_out, obj_type, len);
1491         stream->total_out = hdr;
1492         stream->next_out += hdr;
1493         stream->avail_out -= hdr;
1494 }
1495
1496 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1497 {
1498         int size;
1499         unsigned char *compressed;
1500         z_stream stream;
1501         unsigned char sha1[20];
1502         char *filename;
1503         static char tmpfile[PATH_MAX];
1504         unsigned char hdr[50];
1505         int fd, hdrlen;
1506
1507         /* Normally if we have it in the pack then we do not bother writing
1508          * it out into .git/objects/??/?{38} file.
1509          */
1510         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1511         if (returnsha1)
1512                 hashcpy(returnsha1, sha1);
1513         if (has_sha1_file(sha1))
1514                 return 0;
1515         fd = open(filename, O_RDONLY);
1516         if (fd >= 0) {
1517                 /*
1518                  * FIXME!!! We might do collision checking here, but we'd
1519                  * need to uncompress the old file and check it. Later.
1520                  */
1521                 close(fd);
1522                 return 0;
1523         }
1524
1525         if (errno != ENOENT) {
1526                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1527                 return -1;
1528         }
1529
1530         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1531
1532         fd = mkstemp(tmpfile);
1533         if (fd < 0) {
1534                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1535                 return -1;
1536         }
1537
1538         /* Set it up */
1539         memset(&stream, 0, sizeof(stream));
1540         deflateInit(&stream, zlib_compression_level);
1541         size = 8 + deflateBound(&stream, len+hdrlen);
1542         compressed = xmalloc(size);
1543
1544         /* Compress it */
1545         stream.next_out = compressed;
1546         stream.avail_out = size;
1547
1548         /* First header.. */
1549         stream.next_in = hdr;
1550         stream.avail_in = hdrlen;
1551         setup_object_header(&stream, type, len);
1552
1553         /* Then the data itself.. */
1554         stream.next_in = buf;
1555         stream.avail_in = len;
1556         while (deflate(&stream, Z_FINISH) == Z_OK)
1557                 /* nothing */;
1558         deflateEnd(&stream);
1559         size = stream.total_out;
1560
1561         if (write_buffer(fd, compressed, size) < 0)
1562                 die("unable to write sha1 file");
1563         fchmod(fd, 0444);
1564         close(fd);
1565         free(compressed);
1566
1567         return move_temp_to_file(tmpfile, filename);
1568 }
1569
1570 /*
1571  * We need to unpack and recompress the object for writing
1572  * it out to a different file.
1573  */
1574 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1575 {
1576         size_t size;
1577         z_stream stream;
1578         unsigned char *unpacked;
1579         unsigned long len;
1580         char type[20];
1581         char hdr[50];
1582         int hdrlen;
1583         void *buf;
1584
1585         /* need to unpack and recompress it by itself */
1586         unpacked = read_packed_sha1(sha1, type, &len);
1587
1588         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1589
1590         /* Set it up */
1591         memset(&stream, 0, sizeof(stream));
1592         deflateInit(&stream, zlib_compression_level);
1593         size = deflateBound(&stream, len + hdrlen);
1594         buf = xmalloc(size);
1595
1596         /* Compress it */
1597         stream.next_out = buf;
1598         stream.avail_out = size;
1599
1600         /* First header.. */
1601         stream.next_in = (void *)hdr;
1602         stream.avail_in = hdrlen;
1603         while (deflate(&stream, 0) == Z_OK)
1604                 /* nothing */;
1605
1606         /* Then the data itself.. */
1607         stream.next_in = unpacked;
1608         stream.avail_in = len;
1609         while (deflate(&stream, Z_FINISH) == Z_OK)
1610                 /* nothing */;
1611         deflateEnd(&stream);
1612         free(unpacked);
1613
1614         *objsize = stream.total_out;
1615         return buf;
1616 }
1617
1618 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1619 {
1620         int retval;
1621         unsigned long objsize;
1622         void *buf = map_sha1_file(sha1, &objsize);
1623
1624         if (buf) {
1625                 retval = write_buffer(fd, buf, objsize);
1626                 munmap(buf, objsize);
1627                 return retval;
1628         }
1629
1630         buf = repack_object(sha1, &objsize);
1631         retval = write_buffer(fd, buf, objsize);
1632         free(buf);
1633         return retval;
1634 }
1635
1636 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1637                        size_t bufsize, size_t *bufposn)
1638 {
1639         char tmpfile[PATH_MAX];
1640         int local;
1641         z_stream stream;
1642         unsigned char real_sha1[20];
1643         unsigned char discard[4096];
1644         int ret;
1645         SHA_CTX c;
1646
1647         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1648
1649         local = mkstemp(tmpfile);
1650         if (local < 0)
1651                 return error("Couldn't open %s for %s",
1652                              tmpfile, sha1_to_hex(sha1));
1653
1654         memset(&stream, 0, sizeof(stream));
1655
1656         inflateInit(&stream);
1657
1658         SHA1_Init(&c);
1659
1660         do {
1661                 ssize_t size;
1662                 if (*bufposn) {
1663                         stream.avail_in = *bufposn;
1664                         stream.next_in = (unsigned char *) buffer;
1665                         do {
1666                                 stream.next_out = discard;
1667                                 stream.avail_out = sizeof(discard);
1668                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1669                                 SHA1_Update(&c, discard, sizeof(discard) -
1670                                             stream.avail_out);
1671                         } while (stream.avail_in && ret == Z_OK);
1672                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1673                                 die("unable to write sha1 file");
1674                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1675                                 stream.avail_in);
1676                         *bufposn = stream.avail_in;
1677                         if (ret != Z_OK)
1678                                 break;
1679                 }
1680                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1681                 if (size <= 0) {
1682                         close(local);
1683                         unlink(tmpfile);
1684                         if (!size)
1685                                 return error("Connection closed?");
1686                         perror("Reading from connection");
1687                         return -1;
1688                 }
1689                 *bufposn += size;
1690         } while (1);
1691         inflateEnd(&stream);
1692
1693         close(local);
1694         SHA1_Final(real_sha1, &c);
1695         if (ret != Z_STREAM_END) {
1696                 unlink(tmpfile);
1697                 return error("File %s corrupted", sha1_to_hex(sha1));
1698         }
1699         if (hashcmp(sha1, real_sha1)) {
1700                 unlink(tmpfile);
1701                 return error("File %s has bad hash", sha1_to_hex(sha1));
1702         }
1703
1704         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1705 }
1706
1707 int has_pack_index(const unsigned char *sha1)
1708 {
1709         struct stat st;
1710         if (stat(sha1_pack_index_name(sha1), &st))
1711                 return 0;
1712         return 1;
1713 }
1714
1715 int has_pack_file(const unsigned char *sha1)
1716 {
1717         struct stat st;
1718         if (stat(sha1_pack_name(sha1), &st))
1719                 return 0;
1720         return 1;
1721 }
1722
1723 int has_sha1_pack(const unsigned char *sha1)
1724 {
1725         struct pack_entry e;
1726         return find_pack_entry(sha1, &e);
1727 }
1728
1729 int has_sha1_file(const unsigned char *sha1)
1730 {
1731         struct stat st;
1732         struct pack_entry e;
1733
1734         if (find_pack_entry(sha1, &e))
1735                 return 1;
1736         return find_sha1_file(sha1, &st) ? 1 : 0;
1737 }
1738
1739 /*
1740  * reads from fd as long as possible into a supplied buffer of size bytes.
1741  * If necessary the buffer's size is increased using realloc()
1742  *
1743  * returns 0 if anything went fine and -1 otherwise
1744  *
1745  * NOTE: both buf and size may change, but even when -1 is returned
1746  * you still have to free() it yourself.
1747  */
1748 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1749 {
1750         char* buf = *return_buf;
1751         unsigned long size = *return_size;
1752         int iret;
1753         unsigned long off = 0;
1754
1755         do {
1756                 iret = xread(fd, buf + off, size - off);
1757                 if (iret > 0) {
1758                         off += iret;
1759                         if (off == size) {
1760                                 size *= 2;
1761                                 buf = xrealloc(buf, size);
1762                         }
1763                 }
1764         } while (iret > 0);
1765
1766         *return_buf = buf;
1767         *return_size = off;
1768
1769         if (iret < 0)
1770                 return -1;
1771         return 0;
1772 }
1773
1774 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1775 {
1776         unsigned long size = 4096;
1777         char *buf = malloc(size);
1778         int ret;
1779         unsigned char hdr[50];
1780         int hdrlen;
1781
1782         if (read_pipe(fd, &buf, &size)) {
1783                 free(buf);
1784                 return -1;
1785         }
1786
1787         if (!type)
1788                 type = blob_type;
1789         if (write_object)
1790                 ret = write_sha1_file(buf, size, type, sha1);
1791         else {
1792                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1793                 ret = 0;
1794         }
1795         free(buf);
1796         return ret;
1797 }
1798
1799 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1800 {
1801         unsigned long size = st->st_size;
1802         void *buf;
1803         int ret;
1804         unsigned char hdr[50];
1805         int hdrlen;
1806
1807         buf = "";
1808         if (size)
1809                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1810         close(fd);
1811         if (buf == MAP_FAILED)
1812                 return -1;
1813
1814         if (!type)
1815                 type = blob_type;
1816         if (write_object)
1817                 ret = write_sha1_file(buf, size, type, sha1);
1818         else {
1819                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1820                 ret = 0;
1821         }
1822         if (size)
1823                 munmap(buf, size);
1824         return ret;
1825 }
1826
1827 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1828 {
1829         int fd;
1830         char *target;
1831
1832         switch (st->st_mode & S_IFMT) {
1833         case S_IFREG:
1834                 fd = open(path, O_RDONLY);
1835                 if (fd < 0)
1836                         return error("open(\"%s\"): %s", path,
1837                                      strerror(errno));
1838                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1839                         return error("%s: failed to insert into database",
1840                                      path);
1841                 break;
1842         case S_IFLNK:
1843                 target = xmalloc(st->st_size+1);
1844                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1845                         char *errstr = strerror(errno);
1846                         free(target);
1847                         return error("readlink(\"%s\"): %s", path,
1848                                      errstr);
1849                 }
1850                 if (!write_object) {
1851                         unsigned char hdr[50];
1852                         int hdrlen;
1853                         write_sha1_file_prepare(target, st->st_size, blob_type,
1854                                                 sha1, hdr, &hdrlen);
1855                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1856                         return error("%s: failed to insert into database",
1857                                      path);
1858                 free(target);
1859                 break;
1860         default:
1861                 return error("%s: unsupported file type", path);
1862         }
1863         return 0;
1864 }