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