git.oblomov.eu Git - git/blob - 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] = { 0, };
  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
 485                 pack_mapped += p->pack_size;
 486                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 487                         ; /* nothing */
 488                 fd = open(p->pack_name, O_RDONLY);
 489                 if (fd < 0)
 490                         die("packfile %s cannot be opened", p->pack_name);
 491                 if (fstat(fd, &st)) {
 492                         close(fd);
 493                         die("packfile %s cannot be opened", p->pack_name);
 494                 }
 495                 if (st.st_size != p->pack_size)
 496                         die("packfile %s size mismatch.", p->pack_name);
 497                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 498                 close(fd);
 499                 if (map == MAP_FAILED)
 500                         die("packfile %s cannot be mapped.", p->pack_name);
 501                 p->pack_base = map;
 502
 503                 /* Check if the pack file matches with the index file.
 504                  * this is cheap.
 505                  */
 506                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 507                            (char *) p->pack_base + p->pack_size - 20,
 508                            20)) {
 509
 510                         die("packfile %s does not match index.", p->pack_name);
 511                 }
 512         }
 513         p->pack_last_used = pack_used_ctr++;
 514         p->pack_use_cnt++;
 515         return 0;
 516 }
 517
 518 struct packed_git *add_packed_git(char *path, int path_len, int local)
 519 {
 520         struct stat st;
 521         struct packed_git *p;
 522         unsigned long idx_size;
 523         void *idx_map;
 524         unsigned char sha1[20];
 525
 526         if (check_packed_git_idx(path, &idx_size, &idx_map))
 527                 return NULL;
 528
 529         /* do we have a corresponding .pack file? */
 530         strcpy(path + path_len - 4, ".pack");
 531         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 532                 munmap(idx_map, idx_size);
 533                 return NULL;
 534         }
 535         /* ok, it looks sane as far as we can check without
 536          * actually mapping the pack file.
 537          */
 538         p = xmalloc(sizeof(*p) + path_len + 2);
 539         strcpy(p->pack_name, path);
 540         p->index_size = idx_size;
 541         p->pack_size = st.st_size;
 542         p->index_base = idx_map;
 543         p->next = NULL;
 544         p->pack_base = NULL;
 545         p->pack_last_used = 0;
 546         p->pack_use_cnt = 0;
 547         p->pack_local = local;
 548         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 549                 memcpy(p->sha1, sha1, 20);
 550         return p;
 551 }
 552
 553 struct packed_git *parse_pack_index(unsigned char *sha1)
 554 {
 555         char *path = sha1_pack_index_name(sha1);
 556         return parse_pack_index_file(sha1, path);
 557 }
 558
 559 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 560 {
 561         struct packed_git *p;
 562         unsigned long idx_size;
 563         void *idx_map;
 564         char *path;
 565
 566         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 567                 return NULL;
 568
 569         path = sha1_pack_name(sha1);
 570
 571         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 572         strcpy(p->pack_name, path);
 573         p->index_size = idx_size;
 574         p->pack_size = 0;
 575         p->index_base = idx_map;
 576         p->next = NULL;
 577         p->pack_base = NULL;
 578         p->pack_last_used = 0;
 579         p->pack_use_cnt = 0;
 580         memcpy(p->sha1, sha1, 20);
 581         return p;
 582 }
 583
 584 void install_packed_git(struct packed_git *pack)
 585 {
 586         pack->next = packed_git;
 587         packed_git = pack;
 588 }
 589
 590 static void prepare_packed_git_one(char *objdir, int local)
 591 {
 592         char path[PATH_MAX];
 593         int len;
 594         DIR *dir;
 595         struct dirent *de;
 596
 597         sprintf(path, "%s/pack", objdir);
 598         len = strlen(path);
 599         dir = opendir(path);
 600         if (!dir) {
 601                 if (errno != ENOENT)
 602                         error("unable to open object pack directory: %s: %s",
 603                               path, strerror(errno));
 604                 return;
 605         }
 606         path[len++] = '/';
 607         while ((de = readdir(dir)) != NULL) {
 608                 int namelen = strlen(de->d_name);
 609                 struct packed_git *p;
 610
 611                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 612                         continue;
 613
 614                 /* we have .idx.  Is it a file we can map? */
 615                 strcpy(path + len, de->d_name);
 616                 for (p = packed_git; p; p = p->next) {
 617                         if (!memcmp(path, p->pack_name, len + namelen - 4))
 618                                 break;
 619                 }
 620                 if (p)
 621                         continue;
 622                 p = add_packed_git(path, len + namelen, local);
 623                 if (!p)
 624                         continue;
 625                 p->next = packed_git;
 626                 packed_git = p;
 627         }
 628         closedir(dir);
 629 }
 630
 631 static int prepare_packed_git_run_once = 0;
 632 void prepare_packed_git(void)
 633 {
 634         struct alternate_object_database *alt;
 635
 636         if (prepare_packed_git_run_once)
 637                 return;
 638         prepare_packed_git_one(get_object_directory(), 1);
 639         prepare_alt_odb();
 640         for (alt = alt_odb_list; alt; alt = alt->next) {
 641                 alt->name[-1] = 0;
 642                 prepare_packed_git_one(alt->base, 0);
 643                 alt->name[-1] = '/';
 644         }
 645         prepare_packed_git_run_once = 1;
 646 }
 647
 648 static void reprepare_packed_git(void)
 649 {
 650         prepare_packed_git_run_once = 0;
 651         prepare_packed_git();
 652 }
 653
 654 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 655 {
 656         char header[100];
 657         unsigned char real_sha1[20];
 658         SHA_CTX c;
 659
 660         SHA1_Init(&c);
 661         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 662         SHA1_Update(&c, map, size);
 663         SHA1_Final(real_sha1, &c);
 664         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 665 }
 666
 667 static void *map_sha1_file_internal(const unsigned char *sha1,
 668                                     unsigned long *size)
 669 {
 670         struct stat st;
 671         void *map;
 672         int fd;
 673         char *filename = find_sha1_file(sha1, &st);
 674
 675         if (!filename) {
 676                 return NULL;
 677         }
 678
 679         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 680         if (fd < 0) {
 681                 /* See if it works without O_NOATIME */
 682                 switch (sha1_file_open_flag) {
 683                 default:
 684                         fd = open(filename, O_RDONLY);
 685                         if (fd >= 0)
 686                                 break;
 687                 /* Fallthrough */
 688                 case 0:
 689                         return NULL;
 690                 }
 691
 692                 /* If it failed once, it will probably fail again.
 693                  * Stop using O_NOATIME
 694                  */
 695                 sha1_file_open_flag = 0;
 696         }
 697         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 698         close(fd);
 699         if (map == MAP_FAILED)
 700                 return NULL;
 701         *size = st.st_size;
 702         return map;
 703 }
 704
 705 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 706 {
 707         unsigned char c;
 708         unsigned int word, bits;
 709         unsigned long size;
 710         static const char *typename[8] = {
 711                 NULL,   /* OBJ_EXT */
 712                 "commit", "tree", "blob", "tag",
 713                 NULL, NULL, NULL
 714         };
 715         const char *type;
 716
 717         /* Get the data stream */
 718         memset(stream, 0, sizeof(*stream));
 719         stream->next_in = map;
 720         stream->avail_in = mapsize;
 721         stream->next_out = buffer;
 722         stream->avail_out = bufsiz;
 723
 724         /*
 725          * Is it a zlib-compressed buffer? If so, the first byte
 726          * must be 0x78 (15-bit window size, deflated), and the
 727          * first 16-bit word is evenly divisible by 31
 728          */
 729         word = (map[0] << 8) + map[1];
 730         if (map[0] == 0x78 && !(word % 31)) {
 731                 inflateInit(stream);
 732                 return inflate(stream, 0);
 733         }
 734
 735         c = *map++;
 736         mapsize--;
 737         type = typename[(c >> 4) & 7];
 738         if (!type)
 739                 return -1;
 740
 741         bits = 4;
 742         size = c & 0xf;
 743         while ((c & 0x80)) {
 744                 if (bits >= 8*sizeof(long))
 745                         return -1;
 746                 c = *map++;
 747                 size += (c & 0x7f) << bits;
 748                 bits += 7;
 749                 mapsize--;
 750         }
 751
 752         /* Set up the stream for the rest.. */
 753         stream->next_in = map;
 754         stream->avail_in = mapsize;
 755         inflateInit(stream);
 756
 757         /* And generate the fake traditional header */
 758         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", type, size);
 759         return 0;
 760 }
 761
 762 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 763 {
 764         int bytes = strlen(buffer) + 1;
 765         unsigned char *buf = xmalloc(1+size);
 766         unsigned long n;
 767
 768         n = stream->total_out - bytes;
 769         if (n > size)
 770                 n = size;
 771         memcpy(buf, (char *) buffer + bytes, n);
 772         bytes = n;
 773         if (bytes < size) {
 774                 stream->next_out = buf + bytes;
 775                 stream->avail_out = size - bytes;
 776                 while (inflate(stream, Z_FINISH) == Z_OK)
 777                         /* nothing */;
 778         }
 779         buf[size] = 0;
 780         inflateEnd(stream);
 781         return buf;
 782 }
 783
 784 /*
 785  * We used to just use "sscanf()", but that's actually way
 786  * too permissive for what we want to check. So do an anal
 787  * object header parse by hand.
 788  */
 789 static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 790 {
 791         int i;
 792         unsigned long size;
 793
 794         /*
 795          * The type can be at most ten bytes (including the
 796          * terminating '\0' that we add), and is followed by
 797          * a space.
 798          */
 799         i = 10;
 800         for (;;) {
 801                 char c = *hdr++;
 802                 if (c == ' ')
 803                         break;
 804                 if (!--i)
 805                         return -1;
 806                 *type++ = c;
 807         }
 808         *type = 0;
 809
 810         /*
 811          * The length must follow immediately, and be in canonical
 812          * decimal format (ie "010" is not valid).
 813          */
 814         size = *hdr++ - '0';
 815         if (size > 9)
 816                 return -1;
 817         if (size) {
 818                 for (;;) {
 819                         unsigned long c = *hdr - '0';
 820                         if (c > 9)
 821                                 break;
 822                         hdr++;
 823                         size = size * 10 + c;
 824                 }
 825         }
 826         *sizep = size;
 827
 828         /*
 829          * The length must be followed by a zero byte
 830          */
 831         return *hdr ? -1 : 0;
 832 }
 833
 834 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 835 {
 836         int ret;
 837         z_stream stream;
 838         char hdr[8192];
 839
 840         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 841         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 842                 return NULL;
 843
 844         return unpack_sha1_rest(&stream, hdr, *size);
 845 }
 846
 847 /* forward declaration for a mutually recursive function */
 848 static int packed_object_info(struct pack_entry *entry,
 849                               char *type, unsigned long *sizep);
 850
 851 static int packed_delta_info(unsigned char *base_sha1,
 852                              unsigned long delta_size,
 853                              unsigned long left,
 854                              char *type,
 855                              unsigned long *sizep,
 856                              struct packed_git *p)
 857 {
 858         struct pack_entry base_ent;
 859
 860         if (left < 20)
 861                 die("truncated pack file");
 862
 863         /* The base entry _must_ be in the same pack */
 864         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 865                 die("failed to find delta-pack base object %s",
 866                     sha1_to_hex(base_sha1));
 867
 868         /* We choose to only get the type of the base object and
 869          * ignore potentially corrupt pack file that expects the delta
 870          * based on a base with a wrong size.  This saves tons of
 871          * inflate() calls.
 872          */
 873
 874         if (packed_object_info(&base_ent, type, NULL))
 875                 die("cannot get info for delta-pack base");
 876
 877         if (sizep) {
 878                 const unsigned char *data;
 879                 unsigned char delta_head[64];
 880                 unsigned long result_size;
 881                 z_stream stream;
 882                 int st;
 883
 884                 memset(&stream, 0, sizeof(stream));
 885
 886                 data = stream.next_in = base_sha1 + 20;
 887                 stream.avail_in = left - 20;
 888                 stream.next_out = delta_head;
 889                 stream.avail_out = sizeof(delta_head);
 890
 891                 inflateInit(&stream);
 892                 st = inflate(&stream, Z_FINISH);
 893                 inflateEnd(&stream);
 894                 if ((st != Z_STREAM_END) &&
 895                     stream.total_out != sizeof(delta_head))
 896                         die("delta data unpack-initial failed");
 897
 898                 /* Examine the initial part of the delta to figure out
 899                  * the result size.
 900                  */
 901                 data = delta_head;
 902
 903                 /* ignore base size */
 904                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 905
 906                 /* Read the result size */
 907                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 908                 *sizep = result_size;
 909         }
 910         return 0;
 911 }
 912
 913 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 914         enum object_type *type, unsigned long *sizep)
 915 {
 916         unsigned shift;
 917         unsigned char *pack, c;
 918         unsigned long size;
 919
 920         if (offset >= p->pack_size)
 921                 die("object offset outside of pack file");
 922
 923         pack =  (unsigned char *) p->pack_base + offset;
 924         c = *pack++;
 925         offset++;
 926         *type = (c >> 4) & 7;
 927         size = c & 15;
 928         shift = 4;
 929         while (c & 0x80) {
 930                 if (offset >= p->pack_size)
 931                         die("object offset outside of pack file");
 932                 c = *pack++;
 933                 offset++;
 934                 size += (c & 0x7f) << shift;
 935                 shift += 7;
 936         }
 937         *sizep = size;
 938         return offset;
 939 }
 940
 941 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 942                            unsigned char *base, unsigned long *sizep,
 943                            enum object_type *kindp)
 944 {
 945         unsigned long ptr;
 946         int status = -1;
 947
 948         use_packed_git(p);
 949         ptr = offset;
 950         ptr = unpack_object_header(p, ptr, kindp, sizep);
 951         if (*kindp != OBJ_DELTA)
 952                 goto done;
 953         memcpy(base, (char *) p->pack_base + ptr, 20);
 954         status = 0;
 955  done:
 956         unuse_packed_git(p);
 957         return status;
 958 }
 959
 960 void packed_object_info_detail(struct pack_entry *e,
 961                                char *type,
 962                                unsigned long *size,
 963                                unsigned long *store_size,
 964                                unsigned int *delta_chain_length,
 965                                unsigned char *base_sha1)
 966 {
 967         struct packed_git *p = e->p;
 968         unsigned long offset;
 969         unsigned char *pack;
 970         enum object_type kind;
 971
 972         offset = unpack_object_header(p, e->offset, &kind, size);
 973         pack = (unsigned char *) p->pack_base + offset;
 974         if (kind != OBJ_DELTA)
 975                 *delta_chain_length = 0;
 976         else {
 977                 unsigned int chain_length = 0;
 978                 if (p->pack_size <= offset + 20)
 979                         die("pack file %s records an incomplete delta base",
 980                             p->pack_name);
 981                 memcpy(base_sha1, pack, 20);
 982                 do {
 983                         struct pack_entry base_ent;
 984                         unsigned long junk;
 985
 986                         find_pack_entry_one(pack, &base_ent, p);
 987                         offset = unpack_object_header(p, base_ent.offset,
 988                                                       &kind, &junk);
 989                         pack = (unsigned char *) p->pack_base + offset;
 990                         chain_length++;
 991                 } while (kind == OBJ_DELTA);
 992                 *delta_chain_length = chain_length;
 993         }
 994         switch (kind) {
 995         case OBJ_COMMIT:
 996                 strcpy(type, commit_type);
 997                 break;
 998         case OBJ_TREE:
 999                 strcpy(type, tree_type);
1000                 break;
1001         case OBJ_BLOB:
1002                 strcpy(type, blob_type);
1003                 break;
1004         case OBJ_TAG:
1005                 strcpy(type, tag_type);
1006                 break;
1007         default:
1008                 die("corrupted pack file %s containing object of kind %d",
1009                     p->pack_name, kind);
1010         }
1011         *store_size = 0; /* notyet */
1012 }
1013
1014 static int packed_object_info(struct pack_entry *entry,
1015                               char *type, unsigned long *sizep)
1016 {
1017         struct packed_git *p = entry->p;
1018         unsigned long offset, size, left;
1019         unsigned char *pack;
1020         enum object_type kind;
1021         int retval;
1022
1023         if (use_packed_git(p))
1024                 die("cannot map packed file");
1025
1026         offset = unpack_object_header(p, entry->offset, &kind, &size);
1027         pack = (unsigned char *) p->pack_base + offset;
1028         left = p->pack_size - offset;
1029
1030         switch (kind) {
1031         case OBJ_DELTA:
1032                 retval = packed_delta_info(pack, size, left, type, sizep, p);
1033                 unuse_packed_git(p);
1034                 return retval;
1035         case OBJ_COMMIT:
1036                 strcpy(type, commit_type);
1037                 break;
1038         case OBJ_TREE:
1039                 strcpy(type, tree_type);
1040                 break;
1041         case OBJ_BLOB:
1042                 strcpy(type, blob_type);
1043                 break;
1044         case OBJ_TAG:
1045                 strcpy(type, tag_type);
1046                 break;
1047         default:
1048                 die("corrupted pack file %s containing object of kind %d",
1049                     p->pack_name, kind);
1050         }
1051         if (sizep)
1052                 *sizep = size;
1053         unuse_packed_git(p);
1054         return 0;
1055 }
1056
1057 /* forward declaration for a mutually recursive function */
1058 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
1059
1060 static void *unpack_delta_entry(unsigned char *base_sha1,
1061                                 unsigned long delta_size,
1062                                 unsigned long left,
1063                                 char *type,
1064                                 unsigned long *sizep,
1065                                 struct packed_git *p)
1066 {
1067         struct pack_entry base_ent;
1068         void *data, *delta_data, *result, *base;
1069         unsigned long data_size, result_size, base_size;
1070         z_stream stream;
1071         int st;
1072
1073         if (left < 20)
1074                 die("truncated pack file");
1075
1076         /* The base entry _must_ be in the same pack */
1077         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1078                 die("failed to find delta-pack base object %s",
1079                     sha1_to_hex(base_sha1));
1080         base = unpack_entry_gently(&base_ent, type, &base_size);
1081         if (!base)
1082                 die("failed to read delta-pack base object %s",
1083                     sha1_to_hex(base_sha1));
1084
1085         data = base_sha1 + 20;
1086         data_size = left - 20;
1087         delta_data = xmalloc(delta_size);
1088
1089         memset(&stream, 0, sizeof(stream));
1090
1091         stream.next_in = data;
1092         stream.avail_in = data_size;
1093         stream.next_out = delta_data;
1094         stream.avail_out = delta_size;
1095
1096         inflateInit(&stream);
1097         st = inflate(&stream, Z_FINISH);
1098         inflateEnd(&stream);
1099         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1100                 die("delta data unpack failed");
1101
1102         result = patch_delta(base, base_size,
1103                              delta_data, delta_size,
1104                              &result_size);
1105         if (!result)
1106                 die("failed to apply delta");
1107         free(delta_data);
1108         free(base);
1109         *sizep = result_size;
1110         return result;
1111 }
1112
1113 static void *unpack_non_delta_entry(unsigned char *data,
1114                                     unsigned long size,
1115                                     unsigned long left)
1116 {
1117         int st;
1118         z_stream stream;
1119         unsigned char *buffer;
1120
1121         buffer = xmalloc(size + 1);
1122         buffer[size] = 0;
1123         memset(&stream, 0, sizeof(stream));
1124         stream.next_in = data;
1125         stream.avail_in = left;
1126         stream.next_out = buffer;
1127         stream.avail_out = size;
1128
1129         inflateInit(&stream);
1130         st = inflate(&stream, Z_FINISH);
1131         inflateEnd(&stream);
1132         if ((st != Z_STREAM_END) || stream.total_out != size) {
1133                 free(buffer);
1134                 return NULL;
1135         }
1136
1137         return buffer;
1138 }
1139
1140 static void *unpack_entry(struct pack_entry *entry,
1141                           char *type, unsigned long *sizep)
1142 {
1143         struct packed_git *p = entry->p;
1144         void *retval;
1145
1146         if (use_packed_git(p))
1147                 die("cannot map packed file");
1148         retval = unpack_entry_gently(entry, type, sizep);
1149         unuse_packed_git(p);
1150         if (!retval)
1151                 die("corrupted pack file %s", p->pack_name);
1152         return retval;
1153 }
1154
1155 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1156 void *unpack_entry_gently(struct pack_entry *entry,
1157                           char *type, unsigned long *sizep)
1158 {
1159         struct packed_git *p = entry->p;
1160         unsigned long offset, size, left;
1161         unsigned char *pack;
1162         enum object_type kind;
1163         void *retval;
1164
1165         offset = unpack_object_header(p, entry->offset, &kind, &size);
1166         pack = (unsigned char *) p->pack_base + offset;
1167         left = p->pack_size - offset;
1168         switch (kind) {
1169         case OBJ_DELTA:
1170                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1171                 return retval;
1172         case OBJ_COMMIT:
1173                 strcpy(type, commit_type);
1174                 break;
1175         case OBJ_TREE:
1176                 strcpy(type, tree_type);
1177                 break;
1178         case OBJ_BLOB:
1179                 strcpy(type, blob_type);
1180                 break;
1181         case OBJ_TAG:
1182                 strcpy(type, tag_type);
1183                 break;
1184         default:
1185                 return NULL;
1186         }
1187         *sizep = size;
1188         retval = unpack_non_delta_entry(pack, size, left);
1189         return retval;
1190 }
1191
1192 int num_packed_objects(const struct packed_git *p)
1193 {
1194         /* See check_packed_git_idx() */
1195         return (p->index_size - 20 - 20 - 4*256) / 24;
1196 }
1197
1198 int nth_packed_object_sha1(const struct packed_git *p, int n,
1199                            unsigned char* sha1)
1200 {
1201         void *index = p->index_base + 256;
1202         if (n < 0 || num_packed_objects(p) <= n)
1203                 return -1;
1204         memcpy(sha1, (char *) index + (24 * n) + 4, 20);
1205         return 0;
1206 }
1207
1208 int find_pack_entry_one(const unsigned char *sha1,
1209                         struct pack_entry *e, struct packed_git *p)
1210 {
1211         unsigned int *level1_ofs = p->index_base;
1212         int hi = ntohl(level1_ofs[*sha1]);
1213         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1214         void *index = p->index_base + 256;
1215
1216         do {
1217                 int mi = (lo + hi) / 2;
1218                 int cmp = memcmp((char *) index + (24 * mi) + 4, sha1, 20);
1219                 if (!cmp) {
1220                         e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1221                         memcpy(e->sha1, sha1, 20);
1222                         e->p = p;
1223                         return 1;
1224                 }
1225                 if (cmp > 0)
1226                         hi = mi;
1227                 else
1228                         lo = mi+1;
1229         } while (lo < hi);
1230         return 0;
1231 }
1232
1233 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1234 {
1235         struct packed_git *p;
1236         prepare_packed_git();
1237
1238         for (p = packed_git; p; p = p->next) {
1239                 if (find_pack_entry_one(sha1, e, p))
1240                         return 1;
1241         }
1242         return 0;
1243 }
1244
1245 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1246                                   struct packed_git *packs)
1247 {
1248         struct packed_git *p;
1249         struct pack_entry e;
1250
1251         for (p = packs; p; p = p->next) {
1252                 if (find_pack_entry_one(sha1, &e, p))
1253                         return p;
1254         }
1255         return NULL;
1256
1257 }
1258
1259 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1260 {
1261         int status;
1262         unsigned long mapsize, size;
1263         void *map;
1264         z_stream stream;
1265         char hdr[128];
1266
1267         map = map_sha1_file_internal(sha1, &mapsize);
1268         if (!map) {
1269                 struct pack_entry e;
1270
1271                 if (find_pack_entry(sha1, &e))
1272                         return packed_object_info(&e, type, sizep);
1273                 reprepare_packed_git();
1274                 if (find_pack_entry(sha1, &e))
1275                         return packed_object_info(&e, type, sizep);
1276                 return error("unable to find %s", sha1_to_hex(sha1));
1277         }
1278         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1279                 status = error("unable to unpack %s header",
1280                                sha1_to_hex(sha1));
1281         if (parse_sha1_header(hdr, type, &size) < 0)
1282                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1283         else {
1284                 status = 0;
1285                 if (sizep)
1286                         *sizep = size;
1287         }
1288         inflateEnd(&stream);
1289         munmap(map, mapsize);
1290         return status;
1291 }
1292
1293 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1294 {
1295         struct pack_entry e;
1296
1297         if (!find_pack_entry(sha1, &e)) {
1298                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1299                 return NULL;
1300         }
1301         return unpack_entry(&e, type, size);
1302 }
1303
1304 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1305 {
1306         unsigned long mapsize;
1307         void *map, *buf;
1308         struct pack_entry e;
1309
1310         if (find_pack_entry(sha1, &e))
1311                 return read_packed_sha1(sha1, type, size);
1312         map = map_sha1_file_internal(sha1, &mapsize);
1313         if (map) {
1314                 buf = unpack_sha1_file(map, mapsize, type, size);
1315                 munmap(map, mapsize);
1316                 return buf;
1317         }
1318         reprepare_packed_git();
1319         if (find_pack_entry(sha1, &e))
1320                 return read_packed_sha1(sha1, type, size);
1321         return NULL;
1322 }
1323
1324 void *read_object_with_reference(const unsigned char *sha1,
1325                                  const char *required_type,
1326                                  unsigned long *size,
1327                                  unsigned char *actual_sha1_return)
1328 {
1329         char type[20];
1330         void *buffer;
1331         unsigned long isize;
1332         unsigned char actual_sha1[20];
1333
1334         memcpy(actual_sha1, sha1, 20);
1335         while (1) {
1336                 int ref_length = -1;
1337                 const char *ref_type = NULL;
1338
1339                 buffer = read_sha1_file(actual_sha1, type, &isize);
1340                 if (!buffer)
1341                         return NULL;
1342                 if (!strcmp(type, required_type)) {
1343                         *size = isize;
1344                         if (actual_sha1_return)
1345                                 memcpy(actual_sha1_return, actual_sha1, 20);
1346                         return buffer;
1347                 }
1348                 /* Handle references */
1349                 else if (!strcmp(type, commit_type))
1350                         ref_type = "tree ";
1351                 else if (!strcmp(type, tag_type))
1352                         ref_type = "object ";
1353                 else {
1354                         free(buffer);
1355                         return NULL;
1356                 }
1357                 ref_length = strlen(ref_type);
1358
1359                 if (memcmp(buffer, ref_type, ref_length) ||
1360                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1361                         free(buffer);
1362                         return NULL;
1363                 }
1364                 free(buffer);
1365                 /* Now we have the ID of the referred-to object in
1366                  * actual_sha1.  Check again. */
1367         }
1368 }
1369
1370 char *write_sha1_file_prepare(void *buf,
1371                               unsigned long len,
1372                               const char *type,
1373                               unsigned char *sha1,
1374                               unsigned char *hdr,
1375                               int *hdrlen)
1376 {
1377         SHA_CTX c;
1378
1379         /* Generate the header */
1380         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1381
1382         /* Sha1.. */
1383         SHA1_Init(&c);
1384         SHA1_Update(&c, hdr, *hdrlen);
1385         SHA1_Update(&c, buf, len);
1386         SHA1_Final(sha1, &c);
1387
1388         return sha1_file_name(sha1);
1389 }
1390
1391 /*
1392  * Link the tempfile to the final place, possibly creating the
1393  * last directory level as you do so.
1394  *
1395  * Returns the errno on failure, 0 on success.
1396  */
1397 static int link_temp_to_file(const char *tmpfile, char *filename)
1398 {
1399         int ret;
1400         char *dir;
1401
1402         if (!link(tmpfile, filename))
1403                 return 0;
1404
1405         /*
1406          * Try to mkdir the last path component if that failed.
1407          *
1408          * Re-try the "link()" regardless of whether the mkdir
1409          * succeeds, since a race might mean that somebody
1410          * else succeeded.
1411          */
1412         ret = errno;
1413         dir = strrchr(filename, '/');
1414         if (dir) {
1415                 *dir = 0;
1416                 mkdir(filename, 0777);
1417                 if (adjust_shared_perm(filename))
1418                         return -2;
1419                 *dir = '/';
1420                 if (!link(tmpfile, filename))
1421                         return 0;
1422                 ret = errno;
1423         }
1424         return ret;
1425 }
1426
1427 /*
1428  * Move the just written object into its final resting place
1429  */
1430 int move_temp_to_file(const char *tmpfile, char *filename)
1431 {
1432         int ret = link_temp_to_file(tmpfile, filename);
1433
1434         /*
1435          * Coda hack - coda doesn't like cross-directory links,
1436          * so we fall back to a rename, which will mean that it
1437          * won't be able to check collisions, but that's not a
1438          * big deal.
1439          *
1440          * The same holds for FAT formatted media.
1441          *
1442          * When this succeeds, we just return 0. We have nothing
1443          * left to unlink.
1444          */
1445         if (ret && ret != EEXIST) {
1446                 if (!rename(tmpfile, filename))
1447                         return 0;
1448                 ret = errno;
1449         }
1450         unlink(tmpfile);
1451         if (ret) {
1452                 if (ret != EEXIST) {
1453                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1454                         return -1;
1455                 }
1456                 /* FIXME!!! Collision check here ? */
1457         }
1458
1459         return 0;
1460 }
1461
1462 static int write_buffer(int fd, const void *buf, size_t len)
1463 {
1464         while (len) {
1465                 ssize_t size;
1466
1467                 size = write(fd, buf, len);
1468                 if (!size)
1469                         return error("file write: disk full");
1470                 if (size < 0) {
1471                         if (errno == EINTR || errno == EAGAIN)
1472                                 continue;
1473                         return error("file write error (%s)", strerror(errno));
1474                 }
1475                 len -= size;
1476                 buf = (char *) buf + size;
1477         }
1478         return 0;
1479 }
1480
1481 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1482 {
1483         int hdr_len;
1484         unsigned char c;
1485
1486         c = (type << 4) | (len & 15);
1487         len >>= 4;
1488         hdr_len = 1;
1489         while (len) {
1490                 *hdr++ = c | 0x80;
1491                 hdr_len++;
1492                 c = (len & 0x7f);
1493                 len >>= 7;
1494         }
1495         *hdr = c;
1496         return hdr_len;
1497 }
1498
1499 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1500 {
1501         int obj_type, hdr;
1502
1503         if (use_legacy_headers) {
1504                 while (deflate(stream, 0) == Z_OK)
1505                         /* nothing */;
1506                 return;
1507         }
1508         if (!strcmp(type, blob_type))
1509                 obj_type = OBJ_BLOB;
1510         else if (!strcmp(type, tree_type))
1511                 obj_type = OBJ_TREE;
1512         else if (!strcmp(type, commit_type))
1513                 obj_type = OBJ_COMMIT;
1514         else if (!strcmp(type, tag_type))
1515                 obj_type = OBJ_TAG;
1516         else
1517                 die("trying to generate bogus object of type '%s'", type);
1518         hdr = write_binary_header(stream->next_out, obj_type, len);
1519         stream->total_out = hdr;
1520         stream->next_out += hdr;
1521         stream->avail_out -= hdr;
1522 }
1523
1524 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1525 {
1526         int size;
1527         unsigned char *compressed;
1528         z_stream stream;
1529         unsigned char sha1[20];
1530         char *filename;
1531         static char tmpfile[PATH_MAX];
1532         unsigned char hdr[50];
1533         int fd, hdrlen;
1534
1535         /* Normally if we have it in the pack then we do not bother writing
1536          * it out into .git/objects/??/?{38} file.
1537          */
1538         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1539         if (returnsha1)
1540                 memcpy(returnsha1, sha1, 20);
1541         if (has_sha1_file(sha1))
1542                 return 0;
1543         fd = open(filename, O_RDONLY);
1544         if (fd >= 0) {
1545                 /*
1546                  * FIXME!!! We might do collision checking here, but we'd
1547                  * need to uncompress the old file and check it. Later.
1548                  */
1549                 close(fd);
1550                 return 0;
1551         }
1552
1553         if (errno != ENOENT) {
1554                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1555                 return -1;
1556         }
1557
1558         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1559
1560         fd = mkstemp(tmpfile);
1561         if (fd < 0) {
1562                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1563                 return -1;
1564         }
1565
1566         /* Set it up */
1567         memset(&stream, 0, sizeof(stream));
1568         deflateInit(&stream, zlib_compression_level);
1569         size = 8 + deflateBound(&stream, len+hdrlen);
1570         compressed = xmalloc(size);
1571
1572         /* Compress it */
1573         stream.next_out = compressed;
1574         stream.avail_out = size;
1575
1576         /* First header.. */
1577         stream.next_in = hdr;
1578         stream.avail_in = hdrlen;
1579         setup_object_header(&stream, type, len);
1580
1581         /* Then the data itself.. */
1582         stream.next_in = buf;
1583         stream.avail_in = len;
1584         while (deflate(&stream, Z_FINISH) == Z_OK)
1585                 /* nothing */;
1586         deflateEnd(&stream);
1587         size = stream.total_out;
1588
1589         if (write_buffer(fd, compressed, size) < 0)
1590                 die("unable to write sha1 file");
1591         fchmod(fd, 0444);
1592         close(fd);
1593         free(compressed);
1594
1595         return move_temp_to_file(tmpfile, filename);
1596 }
1597
1598 /*
1599  * We need to unpack and recompress the object for writing
1600  * it out to a different file.
1601  */
1602 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1603 {
1604         size_t size;
1605         z_stream stream;
1606         unsigned char *unpacked;
1607         unsigned long len;
1608         char type[20];
1609         char hdr[50];
1610         int hdrlen;
1611         void *buf;
1612
1613         /* need to unpack and recompress it by itself */
1614         unpacked = read_packed_sha1(sha1, type, &len);
1615
1616         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1617
1618         /* Set it up */
1619         memset(&stream, 0, sizeof(stream));
1620         deflateInit(&stream, zlib_compression_level);
1621         size = deflateBound(&stream, len + hdrlen);
1622         buf = xmalloc(size);
1623
1624         /* Compress it */
1625         stream.next_out = buf;
1626         stream.avail_out = size;
1627
1628         /* First header.. */
1629         stream.next_in = (void *)hdr;
1630         stream.avail_in = hdrlen;
1631         while (deflate(&stream, 0) == Z_OK)
1632                 /* nothing */;
1633
1634         /* Then the data itself.. */
1635         stream.next_in = unpacked;
1636         stream.avail_in = len;
1637         while (deflate(&stream, Z_FINISH) == Z_OK)
1638                 /* nothing */;
1639         deflateEnd(&stream);
1640         free(unpacked);
1641
1642         *objsize = stream.total_out;
1643         return buf;
1644 }
1645
1646 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1647 {
1648         int retval;
1649         unsigned long objsize;
1650         void *buf = map_sha1_file_internal(sha1, &objsize);
1651
1652         if (buf) {
1653                 retval = write_buffer(fd, buf, objsize);
1654                 munmap(buf, objsize);
1655                 return retval;
1656         }
1657
1658         buf = repack_object(sha1, &objsize);
1659         retval = write_buffer(fd, buf, objsize);
1660         free(buf);
1661         return retval;
1662 }
1663
1664 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1665                        size_t bufsize, size_t *bufposn)
1666 {
1667         char tmpfile[PATH_MAX];
1668         int local;
1669         z_stream stream;
1670         unsigned char real_sha1[20];
1671         unsigned char discard[4096];
1672         int ret;
1673         SHA_CTX c;
1674
1675         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1676
1677         local = mkstemp(tmpfile);
1678         if (local < 0)
1679                 return error("Couldn't open %s for %s",
1680                              tmpfile, sha1_to_hex(sha1));
1681
1682         memset(&stream, 0, sizeof(stream));
1683
1684         inflateInit(&stream);
1685
1686         SHA1_Init(&c);
1687
1688         do {
1689                 ssize_t size;
1690                 if (*bufposn) {
1691                         stream.avail_in = *bufposn;
1692                         stream.next_in = (unsigned char *) buffer;
1693                         do {
1694                                 stream.next_out = discard;
1695                                 stream.avail_out = sizeof(discard);
1696                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1697                                 SHA1_Update(&c, discard, sizeof(discard) -
1698                                             stream.avail_out);
1699                         } while (stream.avail_in && ret == Z_OK);
1700                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1701                                 die("unable to write sha1 file");
1702                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1703                                 stream.avail_in);
1704                         *bufposn = stream.avail_in;
1705                         if (ret != Z_OK)
1706                                 break;
1707                 }
1708                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1709                 if (size <= 0) {
1710                         close(local);
1711                         unlink(tmpfile);
1712                         if (!size)
1713                                 return error("Connection closed?");
1714                         perror("Reading from connection");
1715                         return -1;
1716                 }
1717                 *bufposn += size;
1718         } while (1);
1719         inflateEnd(&stream);
1720
1721         close(local);
1722         SHA1_Final(real_sha1, &c);
1723         if (ret != Z_STREAM_END) {
1724                 unlink(tmpfile);
1725                 return error("File %s corrupted", sha1_to_hex(sha1));
1726         }
1727         if (memcmp(sha1, real_sha1, 20)) {
1728                 unlink(tmpfile);
1729                 return error("File %s has bad hash", sha1_to_hex(sha1));
1730         }
1731
1732         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1733 }
1734
1735 int has_pack_index(const unsigned char *sha1)
1736 {
1737         struct stat st;
1738         if (stat(sha1_pack_index_name(sha1), &st))
1739                 return 0;
1740         return 1;
1741 }
1742
1743 int has_pack_file(const unsigned char *sha1)
1744 {
1745         struct stat st;
1746         if (stat(sha1_pack_name(sha1), &st))
1747                 return 0;
1748         return 1;
1749 }
1750
1751 int has_sha1_pack(const unsigned char *sha1)
1752 {
1753         struct pack_entry e;
1754         return find_pack_entry(sha1, &e);
1755 }
1756
1757 int has_sha1_file(const unsigned char *sha1)
1758 {
1759         struct stat st;
1760         struct pack_entry e;
1761
1762         if (find_pack_entry(sha1, &e))
1763                 return 1;
1764         return find_sha1_file(sha1, &st) ? 1 : 0;
1765 }
1766
1767 /*
1768  * reads from fd as long as possible into a supplied buffer of size bytes.
1769  * If necessary the buffer's size is increased using realloc()
1770  *
1771  * returns 0 if anything went fine and -1 otherwise
1772  *
1773  * NOTE: both buf and size may change, but even when -1 is returned
1774  * you still have to free() it yourself.
1775  */
1776 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1777 {
1778         char* buf = *return_buf;
1779         unsigned long size = *return_size;
1780         int iret;
1781         unsigned long off = 0;
1782
1783         do {
1784                 iret = xread(fd, buf + off, size - off);
1785                 if (iret > 0) {
1786                         off += iret;
1787                         if (off == size) {
1788                                 size *= 2;
1789                                 buf = realloc(buf, size);
1790                         }
1791                 }
1792         } while (iret > 0);
1793
1794         *return_buf = buf;
1795         *return_size = off;
1796
1797         if (iret < 0)
1798                 return -1;
1799         return 0;
1800 }
1801
1802 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1803 {
1804         unsigned long size = 4096;
1805         char *buf = malloc(size);
1806         int ret;
1807         unsigned char hdr[50];
1808         int hdrlen;
1809
1810         if (read_pipe(fd, &buf, &size)) {
1811                 free(buf);
1812                 return -1;
1813         }
1814
1815         if (!type)
1816                 type = blob_type;
1817         if (write_object)
1818                 ret = write_sha1_file(buf, size, type, sha1);
1819         else {
1820                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1821                 ret = 0;
1822         }
1823         free(buf);
1824         return ret;
1825 }
1826
1827 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1828 {
1829         unsigned long size = st->st_size;
1830         void *buf;
1831         int ret;
1832         unsigned char hdr[50];
1833         int hdrlen;
1834
1835         buf = "";
1836         if (size)
1837                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1838         close(fd);
1839         if (buf == MAP_FAILED)
1840                 return -1;
1841
1842         if (!type)
1843                 type = blob_type;
1844         if (write_object)
1845                 ret = write_sha1_file(buf, size, type, sha1);
1846         else {
1847                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1848                 ret = 0;
1849         }
1850         if (size)
1851                 munmap(buf, size);
1852         return ret;
1853 }
1854
1855 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1856 {
1857         int fd;
1858         char *target;
1859
1860         switch (st->st_mode & S_IFMT) {
1861         case S_IFREG:
1862                 fd = open(path, O_RDONLY);
1863                 if (fd < 0)
1864                         return error("open(\"%s\"): %s", path,
1865                                      strerror(errno));
1866                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1867                         return error("%s: failed to insert into database",
1868                                      path);
1869                 break;
1870         case S_IFLNK:
1871                 target = xmalloc(st->st_size+1);
1872                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1873                         char *errstr = strerror(errno);
1874                         free(target);
1875                         return error("readlink(\"%s\"): %s", path,
1876                                      errstr);
1877                 }
1878                 if (!write_object) {
1879                         unsigned char hdr[50];
1880                         int hdrlen;
1881                         write_sha1_file_prepare(target, st->st_size, blob_type,
1882                                                 sha1, hdr, &hdrlen);
1883                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1884                         return error("%s: failed to insert into database",
1885                                      path);
1886                 free(target);
1887                 break;
1888         default:
1889                 return error("%s: unsupported file type", path);
1890         }
1891         return 0;
1892 }