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                 get_delta_hdr_size(&data); /* ignore base size */
 812
 813                 /* Read the result size */
 814                 result_size = get_delta_hdr_size(&data);
 815                 *sizep = result_size;
 816         }
 817         return 0;
 818 }
 819
 820 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 821         enum object_type *type, unsigned long *sizep)
 822 {
 823         unsigned shift;
 824         unsigned char *pack, c;
 825         unsigned long size;
 826
 827         if (offset >= p->pack_size)
 828                 die("object offset outside of pack file");
 829
 830         pack =  p->pack_base + offset;
 831         c = *pack++;
 832         offset++;
 833         *type = (c >> 4) & 7;
 834         size = c & 15;
 835         shift = 4;
 836         while (c & 0x80) {
 837                 if (offset >= p->pack_size)
 838                         die("object offset outside of pack file");
 839                 c = *pack++;
 840                 offset++;
 841                 size += (c & 0x7f) << shift;
 842                 shift += 7;
 843         }
 844         *sizep = size;
 845         return offset;
 846 }
 847
 848 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 849                            unsigned char *base, unsigned long *sizep,
 850                            enum object_type *kindp)
 851 {
 852         unsigned long ptr;
 853         int status = -1;
 854
 855         use_packed_git(p);
 856         ptr = offset;
 857         ptr = unpack_object_header(p, ptr, kindp, sizep);
 858         if (*kindp != OBJ_DELTA)
 859                 goto done;
 860         memcpy(base, p->pack_base + ptr, 20);
 861         status = 0;
 862  done:
 863         unuse_packed_git(p);
 864         return status;
 865 }
 866
 867 void packed_object_info_detail(struct pack_entry *e,
 868                                char *type,
 869                                unsigned long *size,
 870                                unsigned long *store_size,
 871                                unsigned int *delta_chain_length,
 872                                unsigned char *base_sha1)
 873 {
 874         struct packed_git *p = e->p;
 875         unsigned long offset, left;
 876         unsigned char *pack;
 877         enum object_type kind;
 878
 879         offset = unpack_object_header(p, e->offset, &kind, size);
 880         pack = p->pack_base + offset;
 881         left = p->pack_size - offset;
 882         if (kind != OBJ_DELTA)
 883                 *delta_chain_length = 0;
 884         else {
 885                 unsigned int chain_length = 0;
 886                 memcpy(base_sha1, pack, 20);
 887                 do {
 888                         struct pack_entry base_ent;
 889                         unsigned long junk;
 890
 891                         find_pack_entry_one(pack, &base_ent, p);
 892                         offset = unpack_object_header(p, base_ent.offset,
 893                                                       &kind, &junk);
 894                         pack = p->pack_base + offset;
 895                         chain_length++;
 896                 } while (kind == OBJ_DELTA);
 897                 *delta_chain_length = chain_length;
 898         }
 899         switch (kind) {
 900         case OBJ_COMMIT:
 901                 strcpy(type, commit_type);
 902                 break;
 903         case OBJ_TREE:
 904                 strcpy(type, tree_type);
 905                 break;
 906         case OBJ_BLOB:
 907                 strcpy(type, blob_type);
 908                 break;
 909         case OBJ_TAG:
 910                 strcpy(type, tag_type);
 911                 break;
 912         default:
 913                 die("corrupted pack file %s containing object of kind %d",
 914                     p->pack_name, kind);
 915         }
 916         *store_size = 0; /* notyet */
 917 }
 918
 919 static int packed_object_info(struct pack_entry *entry,
 920                               char *type, unsigned long *sizep)
 921 {
 922         struct packed_git *p = entry->p;
 923         unsigned long offset, size, left;
 924         unsigned char *pack;
 925         enum object_type kind;
 926         int retval;
 927
 928         if (use_packed_git(p))
 929                 die("cannot map packed file");
 930
 931         offset = unpack_object_header(p, entry->offset, &kind, &size);
 932         pack = p->pack_base + offset;
 933         left = p->pack_size - offset;
 934
 935         switch (kind) {
 936         case OBJ_DELTA:
 937                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 938                 unuse_packed_git(p);
 939                 return retval;
 940         case OBJ_COMMIT:
 941                 strcpy(type, commit_type);
 942                 break;
 943         case OBJ_TREE:
 944                 strcpy(type, tree_type);
 945                 break;
 946         case OBJ_BLOB:
 947                 strcpy(type, blob_type);
 948                 break;
 949         case OBJ_TAG:
 950                 strcpy(type, tag_type);
 951                 break;
 952         default:
 953                 die("corrupted pack file %s containing object of kind %d",
 954                     p->pack_name, kind);
 955         }
 956         if (sizep)
 957                 *sizep = size;
 958         unuse_packed_git(p);
 959         return 0;
 960 }
 961
 962 /* forward declaration for a mutually recursive function */
 963 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
 964
 965 static void *unpack_delta_entry(unsigned char *base_sha1,
 966                                 unsigned long delta_size,
 967                                 unsigned long left,
 968                                 char *type,
 969                                 unsigned long *sizep,
 970                                 struct packed_git *p)
 971 {
 972         struct pack_entry base_ent;
 973         void *data, *delta_data, *result, *base;
 974         unsigned long data_size, result_size, base_size;
 975         z_stream stream;
 976         int st;
 977
 978         if (left < 20)
 979                 die("truncated pack file");
 980
 981         /* The base entry _must_ be in the same pack */
 982         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 983                 die("failed to find delta-pack base object %s",
 984                     sha1_to_hex(base_sha1));
 985         base = unpack_entry_gently(&base_ent, type, &base_size);
 986         if (!base)
 987                 die("failed to read delta-pack base object %s",
 988                     sha1_to_hex(base_sha1));
 989
 990         data = base_sha1 + 20;
 991         data_size = left - 20;
 992         delta_data = xmalloc(delta_size);
 993
 994         memset(&stream, 0, sizeof(stream));
 995
 996         stream.next_in = data;
 997         stream.avail_in = data_size;
 998         stream.next_out = delta_data;
 999         stream.avail_out = delta_size;
1000
1001         inflateInit(&stream);
1002         st = inflate(&stream, Z_FINISH);
1003         inflateEnd(&stream);
1004         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1005                 die("delta data unpack failed");
1006
1007         result = patch_delta(base, base_size,
1008                              delta_data, delta_size,
1009                              &result_size);
1010         if (!result)
1011                 die("failed to apply delta");
1012         free(delta_data);
1013         free(base);
1014         *sizep = result_size;
1015         return result;
1016 }
1017
1018 static void *unpack_non_delta_entry(unsigned char *data,
1019                                     unsigned long size,
1020                                     unsigned long left)
1021 {
1022         int st;
1023         z_stream stream;
1024         unsigned char *buffer;
1025
1026         buffer = xmalloc(size + 1);
1027         buffer[size] = 0;
1028         memset(&stream, 0, sizeof(stream));
1029         stream.next_in = data;
1030         stream.avail_in = left;
1031         stream.next_out = buffer;
1032         stream.avail_out = size;
1033
1034         inflateInit(&stream);
1035         st = inflate(&stream, Z_FINISH);
1036         inflateEnd(&stream);
1037         if ((st != Z_STREAM_END) || stream.total_out != size) {
1038                 free(buffer);
1039                 return NULL;
1040         }
1041
1042         return buffer;
1043 }
1044
1045 static void *unpack_entry(struct pack_entry *entry,
1046                           char *type, unsigned long *sizep)
1047 {
1048         struct packed_git *p = entry->p;
1049         void *retval;
1050
1051         if (use_packed_git(p))
1052                 die("cannot map packed file");
1053         retval = unpack_entry_gently(entry, type, sizep);
1054         unuse_packed_git(p);
1055         if (!retval)
1056                 die("corrupted pack file %s", p->pack_name);
1057         return retval;
1058 }
1059
1060 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1061 void *unpack_entry_gently(struct pack_entry *entry,
1062                           char *type, unsigned long *sizep)
1063 {
1064         struct packed_git *p = entry->p;
1065         unsigned long offset, size, left;
1066         unsigned char *pack;
1067         enum object_type kind;
1068         void *retval;
1069
1070         offset = unpack_object_header(p, entry->offset, &kind, &size);
1071         pack = p->pack_base + offset;
1072         left = p->pack_size - offset;
1073         switch (kind) {
1074         case OBJ_DELTA:
1075                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1076                 return retval;
1077         case OBJ_COMMIT:
1078                 strcpy(type, commit_type);
1079                 break;
1080         case OBJ_TREE:
1081                 strcpy(type, tree_type);
1082                 break;
1083         case OBJ_BLOB:
1084                 strcpy(type, blob_type);
1085                 break;
1086         case OBJ_TAG:
1087                 strcpy(type, tag_type);
1088                 break;
1089         default:
1090                 return NULL;
1091         }
1092         *sizep = size;
1093         retval = unpack_non_delta_entry(pack, size, left);
1094         return retval;
1095 }
1096
1097 int num_packed_objects(const struct packed_git *p)
1098 {
1099         /* See check_packed_git_idx() */
1100         return (p->index_size - 20 - 20 - 4*256) / 24;
1101 }
1102
1103 int nth_packed_object_sha1(const struct packed_git *p, int n,
1104                            unsigned char* sha1)
1105 {
1106         void *index = p->index_base + 256;
1107         if (n < 0 || num_packed_objects(p) <= n)
1108                 return -1;
1109         memcpy(sha1, (index + 24 * n + 4), 20);
1110         return 0;
1111 }
1112
1113 int find_pack_entry_one(const unsigned char *sha1,
1114                         struct pack_entry *e, struct packed_git *p)
1115 {
1116         unsigned int *level1_ofs = p->index_base;
1117         int hi = ntohl(level1_ofs[*sha1]);
1118         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1119         void *index = p->index_base + 256;
1120
1121         do {
1122                 int mi = (lo + hi) / 2;
1123                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1124                 if (!cmp) {
1125                         e->offset = ntohl(*((int*)(index + 24 * mi)));
1126                         memcpy(e->sha1, sha1, 20);
1127                         e->p = p;
1128                         return 1;
1129                 }
1130                 if (cmp > 0)
1131                         hi = mi;
1132                 else
1133                         lo = mi+1;
1134         } while (lo < hi);
1135         return 0;
1136 }
1137
1138 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1139 {
1140         struct packed_git *p;
1141         prepare_packed_git();
1142
1143         for (p = packed_git; p; p = p->next) {
1144                 if (find_pack_entry_one(sha1, e, p))
1145                         return 1;
1146         }
1147         return 0;
1148 }
1149
1150 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1151                                   struct packed_git *packs)
1152 {
1153         struct packed_git *p;
1154         struct pack_entry e;
1155
1156         for (p = packs; p; p = p->next) {
1157                 if (find_pack_entry_one(sha1, &e, p))
1158                         return p;
1159         }
1160         return NULL;
1161
1162 }
1163
1164 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1165 {
1166         int status;
1167         unsigned long mapsize, size;
1168         void *map;
1169         z_stream stream;
1170         char hdr[128];
1171
1172         map = map_sha1_file_internal(sha1, &mapsize);
1173         if (!map) {
1174                 struct pack_entry e;
1175
1176                 if (!find_pack_entry(sha1, &e))
1177                         return error("unable to find %s", sha1_to_hex(sha1));
1178                 return packed_object_info(&e, type, sizep);
1179         }
1180         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1181                 status = error("unable to unpack %s header",
1182                                sha1_to_hex(sha1));
1183         if (parse_sha1_header(hdr, type, &size) < 0)
1184                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1185         else {
1186                 status = 0;
1187                 if (sizep)
1188                         *sizep = size;
1189         }
1190         inflateEnd(&stream);
1191         munmap(map, mapsize);
1192         return status;
1193 }
1194
1195 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1196 {
1197         struct pack_entry e;
1198
1199         if (!find_pack_entry(sha1, &e)) {
1200                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1201                 return NULL;
1202         }
1203         return unpack_entry(&e, type, size);
1204 }
1205
1206 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1207 {
1208         unsigned long mapsize;
1209         void *map, *buf;
1210         struct pack_entry e;
1211
1212         if (find_pack_entry(sha1, &e))
1213                 return read_packed_sha1(sha1, type, size);
1214         map = map_sha1_file_internal(sha1, &mapsize);
1215         if (map) {
1216                 buf = unpack_sha1_file(map, mapsize, type, size);
1217                 munmap(map, mapsize);
1218                 return buf;
1219         }
1220         return NULL;
1221 }
1222
1223 void *read_object_with_reference(const unsigned char *sha1,
1224                                  const char *required_type,
1225                                  unsigned long *size,
1226                                  unsigned char *actual_sha1_return)
1227 {
1228         char type[20];
1229         void *buffer;
1230         unsigned long isize;
1231         unsigned char actual_sha1[20];
1232
1233         memcpy(actual_sha1, sha1, 20);
1234         while (1) {
1235                 int ref_length = -1;
1236                 const char *ref_type = NULL;
1237
1238                 buffer = read_sha1_file(actual_sha1, type, &isize);
1239                 if (!buffer)
1240                         return NULL;
1241                 if (!strcmp(type, required_type)) {
1242                         *size = isize;
1243                         if (actual_sha1_return)
1244                                 memcpy(actual_sha1_return, actual_sha1, 20);
1245                         return buffer;
1246                 }
1247                 /* Handle references */
1248                 else if (!strcmp(type, commit_type))
1249                         ref_type = "tree ";
1250                 else if (!strcmp(type, tag_type))
1251                         ref_type = "object ";
1252                 else {
1253                         free(buffer);
1254                         return NULL;
1255                 }
1256                 ref_length = strlen(ref_type);
1257
1258                 if (memcmp(buffer, ref_type, ref_length) ||
1259                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1260                         free(buffer);
1261                         return NULL;
1262                 }
1263                 free(buffer);
1264                 /* Now we have the ID of the referred-to object in
1265                  * actual_sha1.  Check again. */
1266         }
1267 }
1268
1269 char *write_sha1_file_prepare(void *buf,
1270                               unsigned long len,
1271                               const char *type,
1272                               unsigned char *sha1,
1273                               unsigned char *hdr,
1274                               int *hdrlen)
1275 {
1276         SHA_CTX c;
1277
1278         /* Generate the header */
1279         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1280
1281         /* Sha1.. */
1282         SHA1_Init(&c);
1283         SHA1_Update(&c, hdr, *hdrlen);
1284         SHA1_Update(&c, buf, len);
1285         SHA1_Final(sha1, &c);
1286
1287         return sha1_file_name(sha1);
1288 }
1289
1290 /*
1291  * Link the tempfile to the final place, possibly creating the
1292  * last directory level as you do so.
1293  *
1294  * Returns the errno on failure, 0 on success.
1295  */
1296 static int link_temp_to_file(const char *tmpfile, char *filename)
1297 {
1298         int ret;
1299
1300         if (!link(tmpfile, filename))
1301                 return 0;
1302
1303         /*
1304          * Try to mkdir the last path component if that failed
1305          * with an ENOENT.
1306          *
1307          * Re-try the "link()" regardless of whether the mkdir
1308          * succeeds, since a race might mean that somebody
1309          * else succeeded.
1310          */
1311         ret = errno;
1312         if (ret == ENOENT) {
1313                 char *dir = strrchr(filename, '/');
1314                 if (dir) {
1315                         *dir = 0;
1316                         mkdir(filename, 0777);
1317                         if (adjust_shared_perm(filename))
1318                                 return -2;
1319                         *dir = '/';
1320                         if (!link(tmpfile, filename))
1321                                 return 0;
1322                         ret = errno;
1323                 }
1324         }
1325         return ret;
1326 }
1327
1328 /*
1329  * Move the just written object into its final resting place
1330  */
1331 int move_temp_to_file(const char *tmpfile, char *filename)
1332 {
1333         int ret = link_temp_to_file(tmpfile, filename);
1334
1335         /*
1336          * Coda hack - coda doesn't like cross-directory links,
1337          * so we fall back to a rename, which will mean that it
1338          * won't be able to check collisions, but that's not a
1339          * big deal.
1340          *
1341          * The same holds for FAT formatted media.
1342          *
1343          * When this succeeds, we just return 0. We have nothing
1344          * left to unlink.
1345          */
1346         if (ret && ret != EEXIST) {
1347                 if (!rename(tmpfile, filename))
1348                         return 0;
1349                 ret = errno;
1350         }
1351         unlink(tmpfile);
1352         if (ret) {
1353                 if (ret != EEXIST) {
1354                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1355                         return -1;
1356                 }
1357                 /* FIXME!!! Collision check here ? */
1358         }
1359
1360         return 0;
1361 }
1362
1363 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1364 {
1365         int size;
1366         unsigned char *compressed;
1367         z_stream stream;
1368         unsigned char sha1[20];
1369         char *filename;
1370         static char tmpfile[PATH_MAX];
1371         unsigned char hdr[50];
1372         int fd, hdrlen;
1373
1374         /* Normally if we have it in the pack then we do not bother writing
1375          * it out into .git/objects/??/?{38} file.
1376          */
1377         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1378         if (returnsha1)
1379                 memcpy(returnsha1, sha1, 20);
1380         if (has_sha1_file(sha1))
1381                 return 0;
1382         fd = open(filename, O_RDONLY);
1383         if (fd >= 0) {
1384                 /*
1385                  * FIXME!!! We might do collision checking here, but we'd
1386                  * need to uncompress the old file and check it. Later.
1387                  */
1388                 close(fd);
1389                 return 0;
1390         }
1391
1392         if (errno != ENOENT) {
1393                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1394                 return -1;
1395         }
1396
1397         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1398
1399         fd = mkstemp(tmpfile);
1400         if (fd < 0) {
1401                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1402                 return -1;
1403         }
1404
1405         /* Set it up */
1406         memset(&stream, 0, sizeof(stream));
1407         deflateInit(&stream, Z_BEST_COMPRESSION);
1408         size = deflateBound(&stream, len+hdrlen);
1409         compressed = xmalloc(size);
1410
1411         /* Compress it */
1412         stream.next_out = compressed;
1413         stream.avail_out = size;
1414
1415         /* First header.. */
1416         stream.next_in = hdr;
1417         stream.avail_in = hdrlen;
1418         while (deflate(&stream, 0) == Z_OK)
1419                 /* nothing */;
1420
1421         /* Then the data itself.. */
1422         stream.next_in = buf;
1423         stream.avail_in = len;
1424         while (deflate(&stream, Z_FINISH) == Z_OK)
1425                 /* nothing */;
1426         deflateEnd(&stream);
1427         size = stream.total_out;
1428
1429         if (write(fd, compressed, size) != size)
1430                 die("unable to write file");
1431         fchmod(fd, 0444);
1432         close(fd);
1433         free(compressed);
1434
1435         return move_temp_to_file(tmpfile, filename);
1436 }
1437
1438 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1439 {
1440         ssize_t size;
1441         unsigned long objsize;
1442         int posn = 0;
1443         void *map = map_sha1_file_internal(sha1, &objsize);
1444         void *buf = map;
1445         void *temp_obj = NULL;
1446         z_stream stream;
1447
1448         if (!buf) {
1449                 unsigned char *unpacked;
1450                 unsigned long len;
1451                 char type[20];
1452                 char hdr[50];
1453                 int hdrlen;
1454                 // need to unpack and recompress it by itself
1455                 unpacked = read_packed_sha1(sha1, type, &len);
1456
1457                 hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1458
1459                 /* Set it up */
1460                 memset(&stream, 0, sizeof(stream));
1461                 deflateInit(&stream, Z_BEST_COMPRESSION);
1462                 size = deflateBound(&stream, len + hdrlen);
1463                 temp_obj = buf = xmalloc(size);
1464
1465                 /* Compress it */
1466                 stream.next_out = buf;
1467                 stream.avail_out = size;
1468
1469                 /* First header.. */
1470                 stream.next_in = (void *)hdr;
1471                 stream.avail_in = hdrlen;
1472                 while (deflate(&stream, 0) == Z_OK)
1473                         /* nothing */;
1474
1475                 /* Then the data itself.. */
1476                 stream.next_in = unpacked;
1477                 stream.avail_in = len;
1478                 while (deflate(&stream, Z_FINISH) == Z_OK)
1479                         /* nothing */;
1480                 deflateEnd(&stream);
1481                 free(unpacked);
1482
1483                 objsize = stream.total_out;
1484         }
1485
1486         do {
1487                 size = write(fd, buf + posn, objsize - posn);
1488                 if (size <= 0) {
1489                         if (!size) {
1490                                 fprintf(stderr, "write closed\n");
1491                         } else {
1492                                 perror("write ");
1493                         }
1494                         return -1;
1495                 }
1496                 posn += size;
1497         } while (posn < objsize);
1498
1499         if (map)
1500                 munmap(map, objsize);
1501         if (temp_obj)
1502                 free(temp_obj);
1503
1504         return 0;
1505 }
1506
1507 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1508                        size_t bufsize, size_t *bufposn)
1509 {
1510         char tmpfile[PATH_MAX];
1511         int local;
1512         z_stream stream;
1513         unsigned char real_sha1[20];
1514         unsigned char discard[4096];
1515         int ret;
1516         SHA_CTX c;
1517
1518         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1519
1520         local = mkstemp(tmpfile);
1521         if (local < 0)
1522                 return error("Couldn't open %s for %s",
1523                              tmpfile, sha1_to_hex(sha1));
1524
1525         memset(&stream, 0, sizeof(stream));
1526
1527         inflateInit(&stream);
1528
1529         SHA1_Init(&c);
1530
1531         do {
1532                 ssize_t size;
1533                 if (*bufposn) {
1534                         stream.avail_in = *bufposn;
1535                         stream.next_in = (unsigned char *) buffer;
1536                         do {
1537                                 stream.next_out = discard;
1538                                 stream.avail_out = sizeof(discard);
1539                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1540                                 SHA1_Update(&c, discard, sizeof(discard) -
1541                                             stream.avail_out);
1542                         } while (stream.avail_in && ret == Z_OK);
1543                         write(local, buffer, *bufposn - stream.avail_in);
1544                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1545                                 stream.avail_in);
1546                         *bufposn = stream.avail_in;
1547                         if (ret != Z_OK)
1548                                 break;
1549                 }
1550                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1551                 if (size <= 0) {
1552                         close(local);
1553                         unlink(tmpfile);
1554                         if (!size)
1555                                 return error("Connection closed?");
1556                         perror("Reading from connection");
1557                         return -1;
1558                 }
1559                 *bufposn += size;
1560         } while (1);
1561         inflateEnd(&stream);
1562
1563         close(local);
1564         SHA1_Final(real_sha1, &c);
1565         if (ret != Z_STREAM_END) {
1566                 unlink(tmpfile);
1567                 return error("File %s corrupted", sha1_to_hex(sha1));
1568         }
1569         if (memcmp(sha1, real_sha1, 20)) {
1570                 unlink(tmpfile);
1571                 return error("File %s has bad hash", sha1_to_hex(sha1));
1572         }
1573
1574         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1575 }
1576
1577 int has_pack_index(const unsigned char *sha1)
1578 {
1579         struct stat st;
1580         if (stat(sha1_pack_index_name(sha1), &st))
1581                 return 0;
1582         return 1;
1583 }
1584
1585 int has_pack_file(const unsigned char *sha1)
1586 {
1587         struct stat st;
1588         if (stat(sha1_pack_name(sha1), &st))
1589                 return 0;
1590         return 1;
1591 }
1592
1593 int has_sha1_pack(const unsigned char *sha1)
1594 {
1595         struct pack_entry e;
1596         return find_pack_entry(sha1, &e);
1597 }
1598
1599 int has_sha1_file(const unsigned char *sha1)
1600 {
1601         struct stat st;
1602         struct pack_entry e;
1603
1604         if (find_pack_entry(sha1, &e))
1605                 return 1;
1606         return find_sha1_file(sha1, &st) ? 1 : 0;
1607 }
1608
1609 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1610 {
1611         unsigned long size = 4096;
1612         char *buf = malloc(size);
1613         int iret, ret;
1614         unsigned long off = 0;
1615         unsigned char hdr[50];
1616         int hdrlen;
1617         do {
1618                 iret = read(fd, buf + off, size - off);
1619                 if (iret > 0) {
1620                         off += iret;
1621                         if (off == size) {
1622                                 size *= 2;
1623                                 buf = realloc(buf, size);
1624                         }
1625                 }
1626         } while (iret > 0);
1627         if (iret < 0) {
1628                 free(buf);
1629                 return -1;
1630         }
1631         if (!type)
1632                 type = blob_type;
1633         if (write_object)
1634                 ret = write_sha1_file(buf, off, type, sha1);
1635         else {
1636                 write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
1637                 ret = 0;
1638         }
1639         free(buf);
1640         return ret;
1641 }
1642
1643 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1644 {
1645         unsigned long size = st->st_size;
1646         void *buf;
1647         int ret;
1648         unsigned char hdr[50];
1649         int hdrlen;
1650
1651         buf = "";
1652         if (size)
1653                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1654         close(fd);
1655         if (buf == MAP_FAILED)
1656                 return -1;
1657
1658         if (!type)
1659                 type = blob_type;
1660         if (write_object)
1661                 ret = write_sha1_file(buf, size, type, sha1);
1662         else {
1663                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1664                 ret = 0;
1665         }
1666         if (size)
1667                 munmap(buf, size);
1668         return ret;
1669 }
1670
1671 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1672 {
1673         int fd;
1674         char *target;
1675
1676         switch (st->st_mode & S_IFMT) {
1677         case S_IFREG:
1678                 fd = open(path, O_RDONLY);
1679                 if (fd < 0)
1680                         return error("open(\"%s\"): %s", path,
1681                                      strerror(errno));
1682                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1683                         return error("%s: failed to insert into database",
1684                                      path);
1685                 break;
1686         case S_IFLNK:
1687                 target = xmalloc(st->st_size+1);
1688                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1689                         char *errstr = strerror(errno);
1690                         free(target);
1691                         return error("readlink(\"%s\"): %s", path,
1692                                      errstr);
1693                 }
1694                 if (!write_object) {
1695                         unsigned char hdr[50];
1696                         int hdrlen;
1697                         write_sha1_file_prepare(target, st->st_size, blob_type,
1698                                                 sha1, hdr, &hdrlen);
1699                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1700                         return error("%s: failed to insert into database",
1701                                      path);
1702                 free(target);
1703                 break;
1704         default:
1705                 return error("%s: unsupported file type", path);
1706         }
1707         return 0;
1708 }