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 adjust_shared_perm(const char *path)
  54 {
  55         struct stat st;
  56         int mode;
  57
  58         if (!shared_repository)
  59                 return 0;
  60         if (lstat(path, &st) < 0)
  61                 return -1;
  62         mode = st.st_mode;
  63         if (mode & S_IRUSR)
  64                 mode |= S_IRGRP;
  65         if (mode & S_IWUSR)
  66                 mode |= S_IWGRP;
  67         if (mode & S_IXUSR)
  68                 mode |= S_IXGRP;
  69         if (S_ISDIR(mode))
  70                 mode |= S_ISGID;
  71         if (chmod(path, mode) < 0)
  72                 return -2;
  73         return 0;
  74 }
  75
  76 int safe_create_leading_directories(char *path)
  77 {
  78         char *pos = path;
  79         struct stat st;
  80
  81         if (*pos == '/')
  82                 pos++;
  83
  84         while (pos) {
  85                 pos = strchr(pos, '/');
  86                 if (!pos)
  87                         break;
  88                 *pos = 0;
  89                 if (!stat(path, &st)) {
  90                         /* path exists */
  91                         if (!S_ISDIR(st.st_mode)) {
  92                                 *pos = '/';
  93                                 return -3;
  94                         }
  95                 }
  96                 else if (mkdir(path, 0777)) {
  97                         *pos = '/';
  98                         return -1;
  99                 }
 100                 else if (adjust_shared_perm(path)) {
 101                         *pos = '/';
 102                         return -2;
 103                 }
 104                 *pos++ = '/';
 105         }
 106         return 0;
 107 }
 108
 109 char * sha1_to_hex(const unsigned char *sha1)
 110 {
 111         static char buffer[50];
 112         static const char hex[] = "0123456789abcdef";
 113         char *buf = buffer;
 114         int i;
 115
 116         for (i = 0; i < 20; i++) {
 117                 unsigned int val = *sha1++;
 118                 *buf++ = hex[val >> 4];
 119                 *buf++ = hex[val & 0xf];
 120         }
 121         *buf = '\0';
 122
 123         return buffer;
 124 }
 125
 126 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 127 {
 128         int i;
 129         for (i = 0; i < 20; i++) {
 130                 static char hex[] = "0123456789abcdef";
 131                 unsigned int val = sha1[i];
 132                 char *pos = pathbuf + i*2 + (i > 0);
 133                 *pos++ = hex[val >> 4];
 134                 *pos = hex[val & 0xf];
 135         }
 136 }
 137
 138 /*
 139  * NOTE! This returns a statically allocated buffer, so you have to be
 140  * careful about using it. Do a "strdup()" if you need to save the
 141  * filename.
 142  *
 143  * Also note that this returns the location for creating.  Reading
 144  * SHA1 file can happen from any alternate directory listed in the
 145  * DB_ENVIRONMENT environment variable if it is not found in
 146  * the primary object database.
 147  */
 148 char *sha1_file_name(const unsigned char *sha1)
 149 {
 150         static char *name, *base;
 151
 152         if (!base) {
 153                 const char *sha1_file_directory = get_object_directory();
 154                 int len = strlen(sha1_file_directory);
 155                 base = xmalloc(len + 60);
 156                 memcpy(base, sha1_file_directory, len);
 157                 memset(base+len, 0, 60);
 158                 base[len] = '/';
 159                 base[len+3] = '/';
 160                 name = base + len + 1;
 161         }
 162         fill_sha1_path(name, sha1);
 163         return base;
 164 }
 165
 166 char *sha1_pack_name(const unsigned char *sha1)
 167 {
 168         static const char hex[] = "0123456789abcdef";
 169         static char *name, *base, *buf;
 170         int i;
 171
 172         if (!base) {
 173                 const char *sha1_file_directory = get_object_directory();
 174                 int len = strlen(sha1_file_directory);
 175                 base = xmalloc(len + 60);
 176                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 177                 name = base + len + 11;
 178         }
 179
 180         buf = name;
 181
 182         for (i = 0; i < 20; i++) {
 183                 unsigned int val = *sha1++;
 184                 *buf++ = hex[val >> 4];
 185                 *buf++ = hex[val & 0xf];
 186         }
 187
 188         return base;
 189 }
 190
 191 char *sha1_pack_index_name(const unsigned char *sha1)
 192 {
 193         static const char hex[] = "0123456789abcdef";
 194         static char *name, *base, *buf;
 195         int i;
 196
 197         if (!base) {
 198                 const char *sha1_file_directory = get_object_directory();
 199                 int len = strlen(sha1_file_directory);
 200                 base = xmalloc(len + 60);
 201                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 202                 name = base + len + 11;
 203         }
 204
 205         buf = name;
 206
 207         for (i = 0; i < 20; i++) {
 208                 unsigned int val = *sha1++;
 209                 *buf++ = hex[val >> 4];
 210                 *buf++ = hex[val & 0xf];
 211         }
 212
 213         return base;
 214 }
 215
 216 struct alternate_object_database *alt_odb_list;
 217 static struct alternate_object_database **alt_odb_tail;
 218
 219 /*
 220  * Prepare alternate object database registry.
 221  *
 222  * The variable alt_odb_list points at the list of struct
 223  * alternate_object_database.  The elements on this list come from
 224  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 225  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 226  * whose contents is similar to that environment variable but can be
 227  * LF separated.  Its base points at a statically allocated buffer that
 228  * contains "/the/directory/corresponding/to/.git/objects/...", while
 229  * its name points just after the slash at the end of ".git/objects/"
 230  * in the example above, and has enough space to hold 40-byte hex
 231  * SHA1, an extra slash for the first level indirection, and the
 232  * terminating NUL.
 233  */
 234 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 235                                  const char *relative_base)
 236 {
 237         const char *cp, *last;
 238         struct alternate_object_database *ent;
 239         const char *objdir = get_object_directory();
 240         int base_len = -1;
 241
 242         last = alt;
 243         while (last < ep) {
 244                 cp = last;
 245                 if (cp < ep && *cp == '#') {
 246                         while (cp < ep && *cp != sep)
 247                                 cp++;
 248                         last = cp + 1;
 249                         continue;
 250                 }
 251                 for ( ; cp < ep && *cp != sep; cp++)
 252                         ;
 253                 if (last != cp) {
 254                         struct stat st;
 255                         struct alternate_object_database *alt;
 256                         /* 43 = 40-byte + 2 '/' + terminating NUL */
 257                         int pfxlen = cp - last;
 258                         int entlen = pfxlen + 43;
 259
 260                         if (*last != '/' && relative_base) {
 261                                 /* Relative alt-odb */
 262                                 if (base_len < 0)
 263                                         base_len = strlen(relative_base) + 1;
 264                                 entlen += base_len;
 265                                 pfxlen += base_len;
 266                         }
 267                         ent = xmalloc(sizeof(*ent) + entlen);
 268
 269                         if (*last != '/' && relative_base) {
 270                                 memcpy(ent->base, relative_base, base_len - 1);
 271                                 ent->base[base_len - 1] = '/';
 272                                 memcpy(ent->base + base_len,
 273                                        last, cp - last);
 274                         }
 275                         else
 276                                 memcpy(ent->base, last, pfxlen);
 277
 278                         ent->name = ent->base + pfxlen + 1;
 279                         ent->base[pfxlen + 3] = '/';
 280                         ent->base[pfxlen] = ent->base[entlen-1] = 0;
 281
 282                         /* Detect cases where alternate disappeared */
 283                         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 284                                 error("object directory %s does not exist; "
 285                                       "check .git/objects/info/alternates.",
 286                                       ent->base);
 287                                 goto bad;
 288                         }
 289                         ent->base[pfxlen] = '/';
 290
 291                         /* Prevent the common mistake of listing the same
 292                          * thing twice, or object directory itself.
 293                          */
 294                         for (alt = alt_odb_list; alt; alt = alt->next)
 295                                 if (!memcmp(ent->base, alt->base, pfxlen))
 296                                         goto bad;
 297                         if (!memcmp(ent->base, objdir, pfxlen)) {
 298                         bad:
 299                                 free(ent);
 300                         }
 301                         else {
 302                                 *alt_odb_tail = ent;
 303                                 alt_odb_tail = &(ent->next);
 304                                 ent->next = NULL;
 305                         }
 306                 }
 307                 while (cp < ep && *cp == sep)
 308                         cp++;
 309                 last = cp;
 310         }
 311 }
 312
 313 void prepare_alt_odb(void)
 314 {
 315         char path[PATH_MAX];
 316         char *map;
 317         int fd;
 318         struct stat st;
 319         char *alt;
 320
 321         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 322         if (!alt) alt = "";
 323
 324         if (alt_odb_tail)
 325                 return;
 326         alt_odb_tail = &alt_odb_list;
 327         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
 328
 329         sprintf(path, "%s/info/alternates", get_object_directory());
 330         fd = open(path, O_RDONLY);
 331         if (fd < 0)
 332                 return;
 333         if (fstat(fd, &st) || (st.st_size == 0)) {
 334                 close(fd);
 335                 return;
 336         }
 337         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 338         close(fd);
 339         if (map == MAP_FAILED)
 340                 return;
 341
 342         link_alt_odb_entries(map, map + st.st_size, '\n',
 343                              get_object_directory());
 344         munmap(map, st.st_size);
 345 }
 346
 347 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 348 {
 349         char *name = sha1_file_name(sha1);
 350         struct alternate_object_database *alt;
 351
 352         if (!stat(name, st))
 353                 return name;
 354         prepare_alt_odb();
 355         for (alt = alt_odb_list; alt; alt = alt->next) {
 356                 name = alt->name;
 357                 fill_sha1_path(name, sha1);
 358                 if (!stat(alt->base, st))
 359                         return alt->base;
 360         }
 361         return NULL;
 362 }
 363
 364 #define PACK_MAX_SZ (1<<26)
 365 static int pack_used_ctr;
 366 static unsigned long pack_mapped;
 367 struct packed_git *packed_git;
 368
 369 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 370                                 void **idx_map_)
 371 {
 372         void *idx_map;
 373         unsigned int *index;
 374         unsigned long idx_size;
 375         int nr, i;
 376         int fd = open(path, O_RDONLY);
 377         struct stat st;
 378         if (fd < 0)
 379                 return -1;
 380         if (fstat(fd, &st)) {
 381                 close(fd);
 382                 return -1;
 383         }
 384         idx_size = st.st_size;
 385         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 386         close(fd);
 387         if (idx_map == MAP_FAILED)
 388                 return -1;
 389
 390         index = idx_map;
 391         *idx_map_ = idx_map;
 392         *idx_size_ = idx_size;
 393
 394         /* check index map */
 395         if (idx_size < 4*256 + 20 + 20)
 396                 return error("index file too small");
 397         nr = 0;
 398         for (i = 0; i < 256; i++) {
 399                 unsigned int n = ntohl(index[i]);
 400                 if (n < nr)
 401                         return error("non-monotonic index");
 402                 nr = n;
 403         }
 404
 405         /*
 406          * Total size:
 407          *  - 256 index entries 4 bytes each
 408          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 409          *  - 20-byte SHA1 of the packfile
 410          *  - 20-byte SHA1 file checksum
 411          */
 412         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 413                 return error("wrong index file size");
 414
 415         return 0;
 416 }
 417
 418 static int unuse_one_packed_git(void)
 419 {
 420         struct packed_git *p, *lru = NULL;
 421
 422         for (p = packed_git; p; p = p->next) {
 423                 if (p->pack_use_cnt || !p->pack_base)
 424                         continue;
 425                 if (!lru || p->pack_last_used < lru->pack_last_used)
 426                         lru = p;
 427         }
 428         if (!lru)
 429                 return 0;
 430         munmap(lru->pack_base, lru->pack_size);
 431         lru->pack_base = NULL;
 432         return 1;
 433 }
 434
 435 void unuse_packed_git(struct packed_git *p)
 436 {
 437         p->pack_use_cnt--;
 438 }
 439
 440 int use_packed_git(struct packed_git *p)
 441 {
 442         if (!p->pack_size) {
 443                 struct stat st;
 444                 // We created the struct before we had the pack
 445                 stat(p->pack_name, &st);
 446                 if (!S_ISREG(st.st_mode))
 447                         die("packfile %s not a regular file", p->pack_name);
 448                 p->pack_size = st.st_size;
 449         }
 450         if (!p->pack_base) {
 451                 int fd;
 452                 struct stat st;
 453                 void *map;
 454
 455                 pack_mapped += p->pack_size;
 456                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 457                         ; /* nothing */
 458                 fd = open(p->pack_name, O_RDONLY);
 459                 if (fd < 0)
 460                         die("packfile %s cannot be opened", p->pack_name);
 461                 if (fstat(fd, &st)) {
 462                         close(fd);
 463                         die("packfile %s cannot be opened", p->pack_name);
 464                 }
 465                 if (st.st_size != p->pack_size)
 466                         die("packfile %s size mismatch.", p->pack_name);
 467                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 468                 close(fd);
 469                 if (map == MAP_FAILED)
 470                         die("packfile %s cannot be mapped.", p->pack_name);
 471                 p->pack_base = map;
 472
 473                 /* Check if the pack file matches with the index file.
 474                  * this is cheap.
 475                  */
 476                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 477                            p->pack_base + p->pack_size - 20, 20)) {
 478
 479                         die("packfile %s does not match index.", p->pack_name);
 480                 }
 481         }
 482         p->pack_last_used = pack_used_ctr++;
 483         p->pack_use_cnt++;
 484         return 0;
 485 }
 486
 487 struct packed_git *add_packed_git(char *path, int path_len, int local)
 488 {
 489         struct stat st;
 490         struct packed_git *p;
 491         unsigned long idx_size;
 492         void *idx_map;
 493         unsigned char sha1[20];
 494
 495         if (check_packed_git_idx(path, &idx_size, &idx_map))
 496                 return NULL;
 497
 498         /* do we have a corresponding .pack file? */
 499         strcpy(path + path_len - 4, ".pack");
 500         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 501                 munmap(idx_map, idx_size);
 502                 return NULL;
 503         }
 504         /* ok, it looks sane as far as we can check without
 505          * actually mapping the pack file.
 506          */
 507         p = xmalloc(sizeof(*p) + path_len + 2);
 508         strcpy(p->pack_name, path);
 509         p->index_size = idx_size;
 510         p->pack_size = st.st_size;
 511         p->index_base = idx_map;
 512         p->next = NULL;
 513         p->pack_base = NULL;
 514         p->pack_last_used = 0;
 515         p->pack_use_cnt = 0;
 516         p->pack_local = local;
 517         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 518                 memcpy(p->sha1, sha1, 20);
 519         return p;
 520 }
 521
 522 struct packed_git *parse_pack_index(unsigned char *sha1)
 523 {
 524         char *path = sha1_pack_index_name(sha1);
 525         return parse_pack_index_file(sha1, path);
 526 }
 527
 528 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 529 {
 530         struct packed_git *p;
 531         unsigned long idx_size;
 532         void *idx_map;
 533         char *path;
 534
 535         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 536                 return NULL;
 537
 538         path = sha1_pack_name(sha1);
 539
 540         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 541         strcpy(p->pack_name, path);
 542         p->index_size = idx_size;
 543         p->pack_size = 0;
 544         p->index_base = idx_map;
 545         p->next = NULL;
 546         p->pack_base = NULL;
 547         p->pack_last_used = 0;
 548         p->pack_use_cnt = 0;
 549         memcpy(p->sha1, sha1, 20);
 550         return p;
 551 }
 552
 553 void install_packed_git(struct packed_git *pack)
 554 {
 555         pack->next = packed_git;
 556         packed_git = pack;
 557 }
 558
 559 static void prepare_packed_git_one(char *objdir, int local)
 560 {
 561         char path[PATH_MAX];
 562         int len;
 563         DIR *dir;
 564         struct dirent *de;
 565
 566         sprintf(path, "%s/pack", objdir);
 567         len = strlen(path);
 568         dir = opendir(path);
 569         if (!dir) {
 570                 if (errno != ENOENT)
 571                         error("unable to open object pack directory: %s: %s",
 572                               path, strerror(errno));
 573                 return;
 574         }
 575         path[len++] = '/';
 576         while ((de = readdir(dir)) != NULL) {
 577                 int namelen = strlen(de->d_name);
 578                 struct packed_git *p;
 579
 580                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 581                         continue;
 582
 583                 /* we have .idx.  Is it a file we can map? */
 584                 strcpy(path + len, de->d_name);
 585                 p = add_packed_git(path, len + namelen, local);
 586                 if (!p)
 587                         continue;
 588                 p->next = packed_git;
 589                 packed_git = p;
 590         }
 591         closedir(dir);
 592 }
 593
 594 void prepare_packed_git(void)
 595 {
 596         static int run_once = 0;
 597         struct alternate_object_database *alt;
 598
 599         if (run_once)
 600                 return;
 601         prepare_packed_git_one(get_object_directory(), 1);
 602         prepare_alt_odb();
 603         for (alt = alt_odb_list; alt; alt = alt->next) {
 604                 alt->name[-1] = 0;
 605                 prepare_packed_git_one(alt->base, 0);
 606                 alt->name[-1] = '/';
 607         }
 608         run_once = 1;
 609 }
 610
 611 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 612 {
 613         char header[100];
 614         unsigned char real_sha1[20];
 615         SHA_CTX c;
 616
 617         SHA1_Init(&c);
 618         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 619         SHA1_Update(&c, map, size);
 620         SHA1_Final(real_sha1, &c);
 621         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 622 }
 623
 624 static void *map_sha1_file_internal(const unsigned char *sha1,
 625                                     unsigned long *size)
 626 {
 627         struct stat st;
 628         void *map;
 629         int fd;
 630         char *filename = find_sha1_file(sha1, &st);
 631
 632         if (!filename) {
 633                 return NULL;
 634         }
 635
 636         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 637         if (fd < 0) {
 638                 /* See if it works without O_NOATIME */
 639                 switch (sha1_file_open_flag) {
 640                 default:
 641                         fd = open(filename, O_RDONLY);
 642                         if (fd >= 0)
 643                                 break;
 644                 /* Fallthrough */
 645                 case 0:
 646                         return NULL;
 647                 }
 648
 649                 /* If it failed once, it will probably fail again.
 650                  * Stop using O_NOATIME
 651                  */
 652                 sha1_file_open_flag = 0;
 653         }
 654         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 655         close(fd);
 656         if (map == MAP_FAILED)
 657                 return NULL;
 658         *size = st.st_size;
 659         return map;
 660 }
 661
 662 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 663 {
 664         /* Get the data stream */
 665         memset(stream, 0, sizeof(*stream));
 666         stream->next_in = map;
 667         stream->avail_in = mapsize;
 668         stream->next_out = buffer;
 669         stream->avail_out = size;
 670
 671         inflateInit(stream);
 672         return inflate(stream, 0);
 673 }
 674
 675 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 676 {
 677         int bytes = strlen(buffer) + 1;
 678         unsigned char *buf = xmalloc(1+size);
 679
 680         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 681         bytes = stream->total_out - bytes;
 682         if (bytes < size) {
 683                 stream->next_out = buf + bytes;
 684                 stream->avail_out = size - bytes;
 685                 while (inflate(stream, Z_FINISH) == Z_OK)
 686                         /* nothing */;
 687         }
 688         buf[size] = 0;
 689         inflateEnd(stream);
 690         return buf;
 691 }
 692
 693 /*
 694  * We used to just use "sscanf()", but that's actually way
 695  * too permissive for what we want to check. So do an anal
 696  * object header parse by hand.
 697  */
 698 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 699 {
 700         int i;
 701         unsigned long size;
 702
 703         /*
 704          * The type can be at most ten bytes (including the
 705          * terminating '\0' that we add), and is followed by
 706          * a space.
 707          */
 708         i = 10;
 709         for (;;) {
 710                 char c = *hdr++;
 711                 if (c == ' ')
 712                         break;
 713                 if (!--i)
 714                         return -1;
 715                 *type++ = c;
 716         }
 717         *type = 0;
 718
 719         /*
 720          * The length must follow immediately, and be in canonical
 721          * decimal format (ie "010" is not valid).
 722          */
 723         size = *hdr++ - '0';
 724         if (size > 9)
 725                 return -1;
 726         if (size) {
 727                 for (;;) {
 728                         unsigned long c = *hdr - '0';
 729                         if (c > 9)
 730                                 break;
 731                         hdr++;
 732                         size = size * 10 + c;
 733                 }
 734         }
 735         *sizep = size;
 736
 737         /*
 738          * The length must be followed by a zero byte
 739          */
 740         return *hdr ? -1 : 0;
 741 }
 742
 743 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 744 {
 745         int ret;
 746         z_stream stream;
 747         char hdr[8192];
 748
 749         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 750         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 751                 return NULL;
 752
 753         return unpack_sha1_rest(&stream, hdr, *size);
 754 }
 755
 756 /* forward declaration for a mutually recursive function */
 757 static int packed_object_info(struct pack_entry *entry,
 758                               char *type, unsigned long *sizep);
 759
 760 static int packed_delta_info(unsigned char *base_sha1,
 761                              unsigned long delta_size,
 762                              unsigned long left,
 763                              char *type,
 764                              unsigned long *sizep,
 765                              struct packed_git *p)
 766 {
 767         struct pack_entry base_ent;
 768
 769         if (left < 20)
 770                 die("truncated pack file");
 771
 772         /* The base entry _must_ be in the same pack */
 773         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 774                 die("failed to find delta-pack base object %s",
 775                     sha1_to_hex(base_sha1));
 776
 777         /* We choose to only get the type of the base object and
 778          * ignore potentially corrupt pack file that expects the delta
 779          * based on a base with a wrong size.  This saves tons of
 780          * inflate() calls.
 781          */
 782
 783         if (packed_object_info(&base_ent, type, NULL))
 784                 die("cannot get info for delta-pack base");
 785
 786         if (sizep) {
 787                 const unsigned char *data;
 788                 unsigned char delta_head[64];
 789                 unsigned long result_size;
 790                 z_stream stream;
 791                 int st;
 792
 793                 memset(&stream, 0, sizeof(stream));
 794
 795                 data = stream.next_in = base_sha1 + 20;
 796                 stream.avail_in = left - 20;
 797                 stream.next_out = delta_head;
 798                 stream.avail_out = sizeof(delta_head);
 799
 800                 inflateInit(&stream);
 801                 st = inflate(&stream, Z_FINISH);
 802                 inflateEnd(&stream);
 803                 if ((st != Z_STREAM_END) &&
 804                     stream.total_out != sizeof(delta_head))
 805                         die("delta data unpack-initial failed");
 806
 807                 /* Examine the initial part of the delta to figure out
 808                  * the result size.
 809                  */
 810                 data = delta_head;
 811
 812                 /* ignore base size */
 813                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 814
 815                 /* Read the result size */
 816                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 817                 *sizep = result_size;
 818         }
 819         return 0;
 820 }
 821
 822 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 823         enum object_type *type, unsigned long *sizep)
 824 {
 825         unsigned shift;
 826         unsigned char *pack, c;
 827         unsigned long size;
 828
 829         if (offset >= p->pack_size)
 830                 die("object offset outside of pack file");
 831
 832         pack =  p->pack_base + offset;
 833         c = *pack++;
 834         offset++;
 835         *type = (c >> 4) & 7;
 836         size = c & 15;
 837         shift = 4;
 838         while (c & 0x80) {
 839                 if (offset >= p->pack_size)
 840                         die("object offset outside of pack file");
 841                 c = *pack++;
 842                 offset++;
 843                 size += (c & 0x7f) << shift;
 844                 shift += 7;
 845         }
 846         *sizep = size;
 847         return offset;
 848 }
 849
 850 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 851                            unsigned char *base, unsigned long *sizep,
 852                            enum object_type *kindp)
 853 {
 854         unsigned long ptr;
 855         int status = -1;
 856
 857         use_packed_git(p);
 858         ptr = offset;
 859         ptr = unpack_object_header(p, ptr, kindp, sizep);
 860         if (*kindp != OBJ_DELTA)
 861                 goto done;
 862         memcpy(base, p->pack_base + ptr, 20);
 863         status = 0;
 864  done:
 865         unuse_packed_git(p);
 866         return status;
 867 }
 868
 869 void packed_object_info_detail(struct pack_entry *e,
 870                                char *type,
 871                                unsigned long *size,
 872                                unsigned long *store_size,
 873                                unsigned int *delta_chain_length,
 874                                unsigned char *base_sha1)
 875 {
 876         struct packed_git *p = e->p;
 877         unsigned long offset;
 878         unsigned char *pack;
 879         enum object_type kind;
 880
 881         offset = unpack_object_header(p, e->offset, &kind, size);
 882         pack = p->pack_base + offset;
 883         if (kind != OBJ_DELTA)
 884                 *delta_chain_length = 0;
 885         else {
 886                 unsigned int chain_length = 0;
 887                 if (p->pack_size <= offset + 20)
 888                         die("pack file %s records an incomplete delta base",
 889                             p->pack_name);
 890                 memcpy(base_sha1, pack, 20);
 891                 do {
 892                         struct pack_entry base_ent;
 893                         unsigned long junk;
 894
 895                         find_pack_entry_one(pack, &base_ent, p);
 896                         offset = unpack_object_header(p, base_ent.offset,
 897                                                       &kind, &junk);
 898                         pack = p->pack_base + offset;
 899                         chain_length++;
 900                 } while (kind == OBJ_DELTA);
 901                 *delta_chain_length = chain_length;
 902         }
 903         switch (kind) {
 904         case OBJ_COMMIT:
 905                 strcpy(type, commit_type);
 906                 break;
 907         case OBJ_TREE:
 908                 strcpy(type, tree_type);
 909                 break;
 910         case OBJ_BLOB:
 911                 strcpy(type, blob_type);
 912                 break;
 913         case OBJ_TAG:
 914                 strcpy(type, tag_type);
 915                 break;
 916         default:
 917                 die("corrupted pack file %s containing object of kind %d",
 918                     p->pack_name, kind);
 919         }
 920         *store_size = 0; /* notyet */
 921 }
 922
 923 static int packed_object_info(struct pack_entry *entry,
 924                               char *type, unsigned long *sizep)
 925 {
 926         struct packed_git *p = entry->p;
 927         unsigned long offset, size, left;
 928         unsigned char *pack;
 929         enum object_type kind;
 930         int retval;
 931
 932         if (use_packed_git(p))
 933                 die("cannot map packed file");
 934
 935         offset = unpack_object_header(p, entry->offset, &kind, &size);
 936         pack = p->pack_base + offset;
 937         left = p->pack_size - offset;
 938
 939         switch (kind) {
 940         case OBJ_DELTA:
 941                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 942                 unuse_packed_git(p);
 943                 return retval;
 944         case OBJ_COMMIT:
 945                 strcpy(type, commit_type);
 946                 break;
 947         case OBJ_TREE:
 948                 strcpy(type, tree_type);
 949                 break;
 950         case OBJ_BLOB:
 951                 strcpy(type, blob_type);
 952                 break;
 953         case OBJ_TAG:
 954                 strcpy(type, tag_type);
 955                 break;
 956         default:
 957                 die("corrupted pack file %s containing object of kind %d",
 958                     p->pack_name, kind);
 959         }
 960         if (sizep)
 961                 *sizep = size;
 962         unuse_packed_git(p);
 963         return 0;
 964 }
 965
 966 /* forward declaration for a mutually recursive function */
 967 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 968
 969 static void *unpack_delta_entry(unsigned char *base_sha1,
 970                                 unsigned long delta_size,
 971                                 unsigned long left,
 972                                 char *type,
 973                                 unsigned long *sizep,
 974                                 struct packed_git *p)
 975 {
 976         struct pack_entry base_ent;
 977         void *data, *delta_data, *result, *base;
 978         unsigned long data_size, result_size, base_size;
 979         z_stream stream;
 980         int st;
 981
 982         if (left < 20)
 983                 die("truncated pack file");
 984
 985         /* The base entry _must_ be in the same pack */
 986         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 987                 die("failed to find delta-pack base object %s",
 988                     sha1_to_hex(base_sha1));
 989         base = unpack_entry_gently(&base_ent, type, &base_size);
 990         if (!base)
 991                 die("failed to read delta-pack base object %s",
 992                     sha1_to_hex(base_sha1));
 993
 994         data = base_sha1 + 20;
 995         data_size = left - 20;
 996         delta_data = xmalloc(delta_size);
 997
 998         memset(&stream, 0, sizeof(stream));
 999
1000         stream.next_in = data;
1001         stream.avail_in = data_size;
1002         stream.next_out = delta_data;
1003         stream.avail_out = delta_size;
1004
1005         inflateInit(&stream);
1006         st = inflate(&stream, Z_FINISH);
1007         inflateEnd(&stream);
1008         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1009                 die("delta data unpack failed");
1010
1011         result = patch_delta(base, base_size,
1012                              delta_data, delta_size,
1013                              &result_size);
1014         if (!result)
1015                 die("failed to apply delta");
1016         free(delta_data);
1017         free(base);
1018         *sizep = result_size;
1019         return result;
1020 }
1021
1022 static void *unpack_non_delta_entry(unsigned char *data,
1023                                     unsigned long size,
1024                                     unsigned long left)
1025 {
1026         int st;
1027         z_stream stream;
1028         unsigned char *buffer;
1029
1030         buffer = xmalloc(size + 1);
1031         buffer[size] = 0;
1032         memset(&stream, 0, sizeof(stream));
1033         stream.next_in = data;
1034         stream.avail_in = left;
1035         stream.next_out = buffer;
1036         stream.avail_out = size;
1037
1038         inflateInit(&stream);
1039         st = inflate(&stream, Z_FINISH);
1040         inflateEnd(&stream);
1041         if ((st != Z_STREAM_END) || stream.total_out != size) {
1042                 free(buffer);
1043                 return NULL;
1044         }
1045
1046         return buffer;
1047 }
1048
1049 static void *unpack_entry(struct pack_entry *entry,
1050                           char *type, unsigned long *sizep)
1051 {
1052         struct packed_git *p = entry->p;
1053         void *retval;
1054
1055         if (use_packed_git(p))
1056                 die("cannot map packed file");
1057         retval = unpack_entry_gently(entry, type, sizep);
1058         unuse_packed_git(p);
1059         if (!retval)
1060                 die("corrupted pack file %s", p->pack_name);
1061         return retval;
1062 }
1063
1064 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1065 void *unpack_entry_gently(struct pack_entry *entry,
1066                           char *type, unsigned long *sizep)
1067 {
1068         struct packed_git *p = entry->p;
1069         unsigned long offset, size, left;
1070         unsigned char *pack;
1071         enum object_type kind;
1072         void *retval;
1073
1074         offset = unpack_object_header(p, entry->offset, &kind, &size);
1075         pack = p->pack_base + offset;
1076         left = p->pack_size - offset;
1077         switch (kind) {
1078         case OBJ_DELTA:
1079                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1080                 return retval;
1081         case OBJ_COMMIT:
1082                 strcpy(type, commit_type);
1083                 break;
1084         case OBJ_TREE:
1085                 strcpy(type, tree_type);
1086                 break;
1087         case OBJ_BLOB:
1088                 strcpy(type, blob_type);
1089                 break;
1090         case OBJ_TAG:
1091                 strcpy(type, tag_type);
1092                 break;
1093         default:
1094                 return NULL;
1095         }
1096         *sizep = size;
1097         retval = unpack_non_delta_entry(pack, size, left);
1098         return retval;
1099 }
1100
1101 int num_packed_objects(const struct packed_git *p)
1102 {
1103         /* See check_packed_git_idx() */
1104         return (p->index_size - 20 - 20 - 4*256) / 24;
1105 }
1106
1107 int nth_packed_object_sha1(const struct packed_git *p, int n,
1108                            unsigned char* sha1)
1109 {
1110         void *index = p->index_base + 256;
1111         if (n < 0 || num_packed_objects(p) <= n)
1112                 return -1;
1113         memcpy(sha1, (index + 24 * n + 4), 20);
1114         return 0;
1115 }
1116
1117 int find_pack_entry_one(const unsigned char *sha1,
1118                         struct pack_entry *e, struct packed_git *p)
1119 {
1120         unsigned int *level1_ofs = p->index_base;
1121         int hi = ntohl(level1_ofs[*sha1]);
1122         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1123         void *index = p->index_base + 256;
1124
1125         do {
1126                 int mi = (lo + hi) / 2;
1127                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1128                 if (!cmp) {
1129                         e->offset = ntohl(*((unsigned int *)(index + 24 * mi)));
1130                         memcpy(e->sha1, sha1, 20);
1131                         e->p = p;
1132                         return 1;
1133                 }
1134                 if (cmp > 0)
1135                         hi = mi;
1136                 else
1137                         lo = mi+1;
1138         } while (lo < hi);
1139         return 0;
1140 }
1141
1142 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1143 {
1144         struct packed_git *p;
1145         prepare_packed_git();
1146
1147         for (p = packed_git; p; p = p->next) {
1148                 if (find_pack_entry_one(sha1, e, p))
1149                         return 1;
1150         }
1151         return 0;
1152 }
1153
1154 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1155                                   struct packed_git *packs)
1156 {
1157         struct packed_git *p;
1158         struct pack_entry e;
1159
1160         for (p = packs; p; p = p->next) {
1161                 if (find_pack_entry_one(sha1, &e, p))
1162                         return p;
1163         }
1164         return NULL;
1165
1166 }
1167
1168 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1169 {
1170         int status;
1171         unsigned long mapsize, size;
1172         void *map;
1173         z_stream stream;
1174         char hdr[128];
1175
1176         map = map_sha1_file_internal(sha1, &mapsize);
1177         if (!map) {
1178                 struct pack_entry e;
1179
1180                 if (!find_pack_entry(sha1, &e))
1181                         return error("unable to find %s", sha1_to_hex(sha1));
1182                 return packed_object_info(&e, type, sizep);
1183         }
1184         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1185                 status = error("unable to unpack %s header",
1186                                sha1_to_hex(sha1));
1187         if (parse_sha1_header(hdr, type, &size) < 0)
1188                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1189         else {
1190                 status = 0;
1191                 if (sizep)
1192                         *sizep = size;
1193         }
1194         inflateEnd(&stream);
1195         munmap(map, mapsize);
1196         return status;
1197 }
1198
1199 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1200 {
1201         struct pack_entry e;
1202
1203         if (!find_pack_entry(sha1, &e)) {
1204                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1205                 return NULL;
1206         }
1207         return unpack_entry(&e, type, size);
1208 }
1209
1210 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1211 {
1212         unsigned long mapsize;
1213         void *map, *buf;
1214         struct pack_entry e;
1215
1216         if (find_pack_entry(sha1, &e))
1217                 return read_packed_sha1(sha1, type, size);
1218         map = map_sha1_file_internal(sha1, &mapsize);
1219         if (map) {
1220                 buf = unpack_sha1_file(map, mapsize, type, size);
1221                 munmap(map, mapsize);
1222                 return buf;
1223         }
1224         return NULL;
1225 }
1226
1227 void *read_object_with_reference(const unsigned char *sha1,
1228                                  const char *required_type,
1229                                  unsigned long *size,
1230                                  unsigned char *actual_sha1_return)
1231 {
1232         char type[20];
1233         void *buffer;
1234         unsigned long isize;
1235         unsigned char actual_sha1[20];
1236
1237         memcpy(actual_sha1, sha1, 20);
1238         while (1) {
1239                 int ref_length = -1;
1240                 const char *ref_type = NULL;
1241
1242                 buffer = read_sha1_file(actual_sha1, type, &isize);
1243                 if (!buffer)
1244                         return NULL;
1245                 if (!strcmp(type, required_type)) {
1246                         *size = isize;
1247                         if (actual_sha1_return)
1248                                 memcpy(actual_sha1_return, actual_sha1, 20);
1249                         return buffer;
1250                 }
1251                 /* Handle references */
1252                 else if (!strcmp(type, commit_type))
1253                         ref_type = "tree ";
1254                 else if (!strcmp(type, tag_type))
1255                         ref_type = "object ";
1256                 else {
1257                         free(buffer);
1258                         return NULL;
1259                 }
1260                 ref_length = strlen(ref_type);
1261
1262                 if (memcmp(buffer, ref_type, ref_length) ||
1263                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1264                         free(buffer);
1265                         return NULL;
1266                 }
1267                 free(buffer);
1268                 /* Now we have the ID of the referred-to object in
1269                  * actual_sha1.  Check again. */
1270         }
1271 }
1272
1273 char *write_sha1_file_prepare(void *buf,
1274                               unsigned long len,
1275                               const char *type,
1276                               unsigned char *sha1,
1277                               unsigned char *hdr,
1278                               int *hdrlen)
1279 {
1280         SHA_CTX c;
1281
1282         /* Generate the header */
1283         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1284
1285         /* Sha1.. */
1286         SHA1_Init(&c);
1287         SHA1_Update(&c, hdr, *hdrlen);
1288         SHA1_Update(&c, buf, len);
1289         SHA1_Final(sha1, &c);
1290
1291         return sha1_file_name(sha1);
1292 }
1293
1294 /*
1295  * Link the tempfile to the final place, possibly creating the
1296  * last directory level as you do so.
1297  *
1298  * Returns the errno on failure, 0 on success.
1299  */
1300 static int link_temp_to_file(const char *tmpfile, char *filename)
1301 {
1302         int ret;
1303
1304         if (!link(tmpfile, filename))
1305                 return 0;
1306
1307         /*
1308          * Try to mkdir the last path component if that failed
1309          * with an ENOENT.
1310          *
1311          * Re-try the "link()" regardless of whether the mkdir
1312          * succeeds, since a race might mean that somebody
1313          * else succeeded.
1314          */
1315         ret = errno;
1316         if (ret == ENOENT) {
1317                 char *dir = strrchr(filename, '/');
1318                 if (dir) {
1319                         *dir = 0;
1320                         mkdir(filename, 0777);
1321                         if (adjust_shared_perm(filename))
1322                                 return -2;
1323                         *dir = '/';
1324                         if (!link(tmpfile, filename))
1325                                 return 0;
1326                         ret = errno;
1327                 }
1328         }
1329         return ret;
1330 }
1331
1332 /*
1333  * Move the just written object into its final resting place
1334  */
1335 int move_temp_to_file(const char *tmpfile, char *filename)
1336 {
1337         int ret = link_temp_to_file(tmpfile, filename);
1338
1339         /*
1340          * Coda hack - coda doesn't like cross-directory links,
1341          * so we fall back to a rename, which will mean that it
1342          * won't be able to check collisions, but that's not a
1343          * big deal.
1344          *
1345          * The same holds for FAT formatted media.
1346          *
1347          * When this succeeds, we just return 0. We have nothing
1348          * left to unlink.
1349          */
1350         if (ret && ret != EEXIST) {
1351                 if (!rename(tmpfile, filename))
1352                         return 0;
1353                 ret = errno;
1354         }
1355         unlink(tmpfile);
1356         if (ret) {
1357                 if (ret != EEXIST) {
1358                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1359                         return -1;
1360                 }
1361                 /* FIXME!!! Collision check here ? */
1362         }
1363
1364         return 0;
1365 }
1366
1367 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1368 {
1369         int size;
1370         unsigned char *compressed;
1371         z_stream stream;
1372         unsigned char sha1[20];
1373         char *filename;
1374         static char tmpfile[PATH_MAX];
1375         unsigned char hdr[50];
1376         int fd, hdrlen;
1377
1378         /* Normally if we have it in the pack then we do not bother writing
1379          * it out into .git/objects/??/?{38} file.
1380          */
1381         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1382         if (returnsha1)
1383                 memcpy(returnsha1, sha1, 20);
1384         if (has_sha1_file(sha1))
1385                 return 0;
1386         fd = open(filename, O_RDONLY);
1387         if (fd >= 0) {
1388                 /*
1389                  * FIXME!!! We might do collision checking here, but we'd
1390                  * need to uncompress the old file and check it. Later.
1391                  */
1392                 close(fd);
1393                 return 0;
1394         }
1395
1396         if (errno != ENOENT) {
1397                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1398                 return -1;
1399         }
1400
1401         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1402
1403         fd = mkstemp(tmpfile);
1404         if (fd < 0) {
1405                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1406                 return -1;
1407         }
1408
1409         /* Set it up */
1410         memset(&stream, 0, sizeof(stream));
1411         deflateInit(&stream, Z_BEST_COMPRESSION);
1412         size = deflateBound(&stream, len+hdrlen);
1413         compressed = xmalloc(size);
1414
1415         /* Compress it */
1416         stream.next_out = compressed;
1417         stream.avail_out = size;
1418
1419         /* First header.. */
1420         stream.next_in = hdr;
1421         stream.avail_in = hdrlen;
1422         while (deflate(&stream, 0) == Z_OK)
1423                 /* nothing */;
1424
1425         /* Then the data itself.. */
1426         stream.next_in = buf;
1427         stream.avail_in = len;
1428         while (deflate(&stream, Z_FINISH) == Z_OK)
1429                 /* nothing */;
1430         deflateEnd(&stream);
1431         size = stream.total_out;
1432
1433         if (write(fd, compressed, size) != size)
1434                 die("unable to write file");
1435         fchmod(fd, 0444);
1436         close(fd);
1437         free(compressed);
1438
1439         return move_temp_to_file(tmpfile, filename);
1440 }
1441
1442 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1443 {
1444         ssize_t size;
1445         unsigned long objsize;
1446         int posn = 0;
1447         void *map = map_sha1_file_internal(sha1, &objsize);
1448         void *buf = map;
1449         void *temp_obj = NULL;
1450         z_stream stream;
1451
1452         if (!buf) {
1453                 unsigned char *unpacked;
1454                 unsigned long len;
1455                 char type[20];
1456                 char hdr[50];
1457                 int hdrlen;
1458                 // need to unpack and recompress it by itself
1459                 unpacked = read_packed_sha1(sha1, type, &len);
1460
1461                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1462
1463                 /* Set it up */
1464                 memset(&stream, 0, sizeof(stream));
1465                 deflateInit(&stream, Z_BEST_COMPRESSION);
1466                 size = deflateBound(&stream, len + hdrlen);
1467                 temp_obj = buf = xmalloc(size);
1468
1469                 /* Compress it */
1470                 stream.next_out = buf;
1471                 stream.avail_out = size;
1472
1473                 /* First header.. */
1474                 stream.next_in = (void *)hdr;
1475                 stream.avail_in = hdrlen;
1476                 while (deflate(&stream, 0) == Z_OK)
1477                         /* nothing */;
1478
1479                 /* Then the data itself.. */
1480                 stream.next_in = unpacked;
1481                 stream.avail_in = len;
1482                 while (deflate(&stream, Z_FINISH) == Z_OK)
1483                         /* nothing */;
1484                 deflateEnd(&stream);
1485                 free(unpacked);
1486
1487                 objsize = stream.total_out;
1488         }
1489
1490         do {
1491                 size = write(fd, buf + posn, objsize - posn);
1492                 if (size <= 0) {
1493                         if (!size) {
1494                                 fprintf(stderr, "write closed\n");
1495                         } else {
1496                                 perror("write ");
1497                         }
1498                         return -1;
1499                 }
1500                 posn += size;
1501         } while (posn < objsize);
1502
1503         if (map)
1504                 munmap(map, objsize);
1505         if (temp_obj)
1506                 free(temp_obj);
1507
1508         return 0;
1509 }
1510
1511 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1512                        size_t bufsize, size_t *bufposn)
1513 {
1514         char tmpfile[PATH_MAX];
1515         int local;
1516         z_stream stream;
1517         unsigned char real_sha1[20];
1518         unsigned char discard[4096];
1519         int ret;
1520         SHA_CTX c;
1521
1522         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1523
1524         local = mkstemp(tmpfile);
1525         if (local < 0)
1526                 return error("Couldn't open %s for %s",
1527                              tmpfile, sha1_to_hex(sha1));
1528
1529         memset(&stream, 0, sizeof(stream));
1530
1531         inflateInit(&stream);
1532
1533         SHA1_Init(&c);
1534
1535         do {
1536                 ssize_t size;
1537                 if (*bufposn) {
1538                         stream.avail_in = *bufposn;
1539                         stream.next_in = (unsigned char *) buffer;
1540                         do {
1541                                 stream.next_out = discard;
1542                                 stream.avail_out = sizeof(discard);
1543                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1544                                 SHA1_Update(&c, discard, sizeof(discard) -
1545                                             stream.avail_out);
1546                         } while (stream.avail_in && ret == Z_OK);
1547                         write(local, buffer, *bufposn - stream.avail_in);
1548                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1549                                 stream.avail_in);
1550                         *bufposn = stream.avail_in;
1551                         if (ret != Z_OK)
1552                                 break;
1553                 }
1554                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1555                 if (size <= 0) {
1556                         close(local);
1557                         unlink(tmpfile);
1558                         if (!size)
1559                                 return error("Connection closed?");
1560                         perror("Reading from connection");
1561                         return -1;
1562                 }
1563                 *bufposn += size;
1564         } while (1);
1565         inflateEnd(&stream);
1566
1567         close(local);
1568         SHA1_Final(real_sha1, &c);
1569         if (ret != Z_STREAM_END) {
1570                 unlink(tmpfile);
1571                 return error("File %s corrupted", sha1_to_hex(sha1));
1572         }
1573         if (memcmp(sha1, real_sha1, 20)) {
1574                 unlink(tmpfile);
1575                 return error("File %s has bad hash", sha1_to_hex(sha1));
1576         }
1577
1578         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1579 }
1580
1581 int has_pack_index(const unsigned char *sha1)
1582 {
1583         struct stat st;
1584         if (stat(sha1_pack_index_name(sha1), &st))
1585                 return 0;
1586         return 1;
1587 }
1588
1589 int has_pack_file(const unsigned char *sha1)
1590 {
1591         struct stat st;
1592         if (stat(sha1_pack_name(sha1), &st))
1593                 return 0;
1594         return 1;
1595 }
1596
1597 int has_sha1_pack(const unsigned char *sha1)
1598 {
1599         struct pack_entry e;
1600         return find_pack_entry(sha1, &e);
1601 }
1602
1603 int has_sha1_file(const unsigned char *sha1)
1604 {
1605         struct stat st;
1606         struct pack_entry e;
1607
1608         if (find_pack_entry(sha1, &e))
1609                 return 1;
1610         return find_sha1_file(sha1, &st) ? 1 : 0;
1611 }
1612
1613 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1614 {
1615         unsigned long size = 4096;
1616         char *buf = malloc(size);
1617         int iret, ret;
1618         unsigned long off = 0;
1619         unsigned char hdr[50];
1620         int hdrlen;
1621         do {
1622                 iret = read(fd, buf + off, size - off);
1623                 if (iret > 0) {
1624                         off += iret;
1625                         if (off == size) {
1626                                 size *= 2;
1627                                 buf = realloc(buf, size);
1628                         }
1629                 }
1630         } while (iret > 0);
1631         if (iret < 0) {
1632                 free(buf);
1633                 return -1;
1634         }
1635         if (!type)
1636                 type = blob_type;
1637         if (write_object)
1638                 ret = write_sha1_file(buf, off, type, sha1);
1639         else {
1640                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1641                 ret = 0;
1642         }
1643         free(buf);
1644         return ret;
1645 }
1646
1647 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1648 {
1649         unsigned long size = st->st_size;
1650         void *buf;
1651         int ret;
1652         unsigned char hdr[50];
1653         int hdrlen;
1654
1655         buf = "";
1656         if (size)
1657                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1658         close(fd);
1659         if (buf == MAP_FAILED)
1660                 return -1;
1661
1662         if (!type)
1663                 type = blob_type;
1664         if (write_object)
1665                 ret = write_sha1_file(buf, size, type, sha1);
1666         else {
1667                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1668                 ret = 0;
1669         }
1670         if (size)
1671                 munmap(buf, size);
1672         return ret;
1673 }
1674
1675 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1676 {
1677         int fd;
1678         char *target;
1679
1680         switch (st->st_mode & S_IFMT) {
1681         case S_IFREG:
1682                 fd = open(path, O_RDONLY);
1683                 if (fd < 0)
1684                         return error("open(\"%s\"): %s", path,
1685                                      strerror(errno));
1686                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1687                         return error("%s: failed to insert into database",
1688                                      path);
1689                 break;
1690         case S_IFLNK:
1691                 target = xmalloc(st->st_size+1);
1692                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1693                         char *errstr = strerror(errno);
1694                         free(target);
1695                         return error("readlink(\"%s\"): %s", path,
1696                                      errstr);
1697                 }
1698                 if (!write_object) {
1699                         unsigned char hdr[50];
1700                         int hdrlen;
1701                         write_sha1_file_prepare(target, st->st_size, blob_type,
1702                                                 sha1, hdr, &hdrlen);
1703                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1704                         return error("%s: failed to insert into database",
1705                                      path);
1706                 free(target);
1707                 break;
1708         default:
1709                 return error("%s: unsupported file type", path);
1710         }
1711         return 0;
1712 }