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