sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include "cache.h"
  10 #include "delta.h"
  11 #include "pack.h"
  12 #include "blob.h"
  13 #include "commit.h"
  14 #include "tag.h"
  15 #include "tree.h"
  16
  17 #ifndef O_NOATIME
  18 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  19 #define O_NOATIME 01000000
  20 #else
  21 #define O_NOATIME 0
  22 #endif
  23 #endif
  24
  25 const unsigned char null_sha1[20] = { 0, };
  26
  27 static unsigned int sha1_file_open_flag = O_NOATIME;
  28
  29 static unsigned hexval(char c)
  30 {
  31         if (c >= '0' && c <= '9')
  32                 return c - '0';
  33         if (c >= 'a' && c <= 'f')
  34                 return c - 'a' + 10;
  35         if (c >= 'A' && c <= 'F')
  36                 return c - 'A' + 10;
  37         return ~0;
  38 }
  39
  40 int get_sha1_hex(const char *hex, unsigned char *sha1)
  41 {
  42         int i;
  43         for (i = 0; i < 20; i++) {
  44                 unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
  45                 if (val & ~0xff)
  46                         return -1;
  47                 *sha1++ = val;
  48                 hex += 2;
  49         }
  50         return 0;
  51 }
  52
  53 int adjust_shared_perm(const char *path)
  54 {
  55         struct stat st;
  56         int mode;
  57
  58         if (!shared_repository)
  59                 return 0;
  60         if (lstat(path, &st) < 0)
  61                 return -1;
  62         mode = st.st_mode;
  63         if (mode & S_IRUSR)
  64                 mode |= S_IRGRP;
  65         if (mode & S_IWUSR)
  66                 mode |= S_IWGRP;
  67         if (mode & S_IXUSR)
  68                 mode |= S_IXGRP;
  69         if (S_ISDIR(mode))
  70                 mode |= S_ISGID;
  71         if (chmod(path, mode) < 0)
  72                 return -2;
  73         return 0;
  74 }
  75
  76 int safe_create_leading_directories(char *path)
  77 {
  78         char *pos = path;
  79         struct stat st;
  80
  81         if (*pos == '/')
  82                 pos++;
  83
  84         while (pos) {
  85                 pos = strchr(pos, '/');
  86                 if (!pos)
  87                         break;
  88                 *pos = 0;
  89                 if (!stat(path, &st)) {
  90                         /* path exists */
  91                         if (!S_ISDIR(st.st_mode)) {
  92                                 *pos = '/';
  93                                 return -3;
  94                         }
  95                 }
  96                 else if (mkdir(path, 0777)) {
  97                         *pos = '/';
  98                         return -1;
  99                 }
 100                 else if (adjust_shared_perm(path)) {
 101                         *pos = '/';
 102                         return -2;
 103                 }
 104                 *pos++ = '/';
 105         }
 106         return 0;
 107 }
 108
 109 char * sha1_to_hex(const unsigned char *sha1)
 110 {
 111         static int bufno;
 112         static char hexbuffer[4][50];
 113         static const char hex[] = "0123456789abcdef";
 114         char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
 115         int i;
 116
 117         for (i = 0; i < 20; i++) {
 118                 unsigned int val = *sha1++;
 119                 *buf++ = hex[val >> 4];
 120                 *buf++ = hex[val & 0xf];
 121         }
 122         *buf = '\0';
 123
 124         return buffer;
 125 }
 126
 127 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 128 {
 129         int i;
 130         for (i = 0; i < 20; i++) {
 131                 static char hex[] = "0123456789abcdef";
 132                 unsigned int val = sha1[i];
 133                 char *pos = pathbuf + i*2 + (i > 0);
 134                 *pos++ = hex[val >> 4];
 135                 *pos = hex[val & 0xf];
 136         }
 137 }
 138
 139 /*
 140  * NOTE! This returns a statically allocated buffer, so you have to be
 141  * careful about using it. Do a "strdup()" if you need to save the
 142  * filename.
 143  *
 144  * Also note that this returns the location for creating.  Reading
 145  * SHA1 file can happen from any alternate directory listed in the
 146  * DB_ENVIRONMENT environment variable if it is not found in
 147  * the primary object database.
 148  */
 149 char *sha1_file_name(const unsigned char *sha1)
 150 {
 151         static char *name, *base;
 152
 153         if (!base) {
 154                 const char *sha1_file_directory = get_object_directory();
 155                 int len = strlen(sha1_file_directory);
 156                 base = xmalloc(len + 60);
 157                 memcpy(base, sha1_file_directory, len);
 158                 memset(base+len, 0, 60);
 159                 base[len] = '/';
 160                 base[len+3] = '/';
 161                 name = base + len + 1;
 162         }
 163         fill_sha1_path(name, sha1);
 164         return base;
 165 }
 166
 167 char *sha1_pack_name(const unsigned char *sha1)
 168 {
 169         static const char hex[] = "0123456789abcdef";
 170         static char *name, *base, *buf;
 171         int i;
 172
 173         if (!base) {
 174                 const char *sha1_file_directory = get_object_directory();
 175                 int len = strlen(sha1_file_directory);
 176                 base = xmalloc(len + 60);
 177                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 178                 name = base + len + 11;
 179         }
 180
 181         buf = name;
 182
 183         for (i = 0; i < 20; i++) {
 184                 unsigned int val = *sha1++;
 185                 *buf++ = hex[val >> 4];
 186                 *buf++ = hex[val & 0xf];
 187         }
 188
 189         return base;
 190 }
 191
 192 char *sha1_pack_index_name(const unsigned char *sha1)
 193 {
 194         static const char hex[] = "0123456789abcdef";
 195         static char *name, *base, *buf;
 196         int i;
 197
 198         if (!base) {
 199                 const char *sha1_file_directory = get_object_directory();
 200                 int len = strlen(sha1_file_directory);
 201                 base = xmalloc(len + 60);
 202                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 203                 name = base + len + 11;
 204         }
 205
 206         buf = name;
 207
 208         for (i = 0; i < 20; i++) {
 209                 unsigned int val = *sha1++;
 210                 *buf++ = hex[val >> 4];
 211                 *buf++ = hex[val & 0xf];
 212         }
 213
 214         return base;
 215 }
 216
 217 struct alternate_object_database *alt_odb_list;
 218 static struct alternate_object_database **alt_odb_tail;
 219
 220 static void read_info_alternates(const char * alternates, int depth);
 221
 222 /*
 223  * Prepare alternate object database registry.
 224  *
 225  * The variable alt_odb_list points at the list of struct
 226  * alternate_object_database.  The elements on this list come from
 227  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 228  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 229  * whose contents is similar to that environment variable but can be
 230  * LF separated.  Its base points at a statically allocated buffer that
 231  * contains "/the/directory/corresponding/to/.git/objects/...", while
 232  * its name points just after the slash at the end of ".git/objects/"
 233  * in the example above, and has enough space to hold 40-byte hex
 234  * SHA1, an extra slash for the first level indirection, and the
 235  * terminating NUL.
 236  */
 237 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 238 {
 239         struct stat st;
 240         const char *objdir = get_object_directory();
 241         struct alternate_object_database *ent;
 242         struct alternate_object_database *alt;
 243         /* 43 = 40-byte + 2 '/' + terminating NUL */
 244         int pfxlen = len;
 245         int entlen = pfxlen + 43;
 246         int base_len = -1;
 247
 248         if (*entry != '/' && relative_base) {
 249                 /* Relative alt-odb */
 250                 if (base_len < 0)
 251                         base_len = strlen(relative_base) + 1;
 252                 entlen += base_len;
 253                 pfxlen += base_len;
 254         }
 255         ent = xmalloc(sizeof(*ent) + entlen);
 256
 257         if (*entry != '/' && relative_base) {
 258                 memcpy(ent->base, relative_base, base_len - 1);
 259                 ent->base[base_len - 1] = '/';
 260                 memcpy(ent->base + base_len, entry, len);
 261         }
 262         else
 263                 memcpy(ent->base, entry, pfxlen);
 264
 265         ent->name = ent->base + pfxlen + 1;
 266         ent->base[pfxlen + 3] = '/';
 267         ent->base[pfxlen] = ent->base[entlen-1] = 0;
 268
 269         /* Detect cases where alternate disappeared */
 270         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 271                 error("object directory %s does not exist; "
 272                       "check .git/objects/info/alternates.",
 273                       ent->base);
 274                 free(ent);
 275                 return -1;
 276         }
 277
 278         /* Prevent the common mistake of listing the same
 279          * thing twice, or object directory itself.
 280          */
 281         for (alt = alt_odb_list; alt; alt = alt->next) {
 282                 if (!memcmp(ent->base, alt->base, pfxlen)) {
 283                         free(ent);
 284                         return -1;
 285                 }
 286         }
 287         if (!memcmp(ent->base, objdir, pfxlen)) {
 288                 free(ent);
 289                 return -1;
 290         }
 291
 292         /* add the alternate entry */
 293         *alt_odb_tail = ent;
 294         alt_odb_tail = &(ent->next);
 295         ent->next = NULL;
 296
 297         /* recursively add alternates */
 298         read_info_alternates(ent->base, depth + 1);
 299
 300         ent->base[pfxlen] = '/';
 301
 302         return 0;
 303 }
 304
 305 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 306                                  const char *relative_base, int depth)
 307 {
 308         const char *cp, *last;
 309
 310         if (depth > 5) {
 311                 error("%s: ignoring alternate object stores, nesting too deep.",
 312                                 relative_base);
 313                 return;
 314         }
 315
 316         last = alt;
 317         while (last < ep) {
 318                 cp = last;
 319                 if (cp < ep && *cp == '#') {
 320                         while (cp < ep && *cp != sep)
 321                                 cp++;
 322                         last = cp + 1;
 323                         continue;
 324                 }
 325                 while (cp < ep && *cp != sep)
 326                         cp++;
 327                 if (last != cp) {
 328                         if ((*last != '/') && depth) {
 329                                 error("%s: ignoring relative alternate object store %s",
 330                                                 relative_base, last);
 331                         } else {
 332                                 link_alt_odb_entry(last, cp - last,
 333                                                 relative_base, depth);
 334                         }
 335                 }
 336                 while (cp < ep && *cp == sep)
 337                         cp++;
 338                 last = cp;
 339         }
 340 }
 341
 342 static void read_info_alternates(const char * relative_base, int depth)
 343 {
 344         char *map;
 345         struct stat st;
 346         char path[PATH_MAX];
 347         int fd;
 348
 349         sprintf(path, "%s/info/alternates", relative_base);
 350         fd = open(path, O_RDONLY);
 351         if (fd < 0)
 352                 return;
 353         if (fstat(fd, &st) || (st.st_size == 0)) {
 354                 close(fd);
 355                 return;
 356         }
 357         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 358         close(fd);
 359         if (map == MAP_FAILED)
 360                 return;
 361
 362         link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 363
 364         munmap(map, st.st_size);
 365 }
 366
 367 void prepare_alt_odb(void)
 368 {
 369         char *alt;
 370
 371         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 372         if (!alt) alt = "";
 373
 374         if (alt_odb_tail)
 375                 return;
 376         alt_odb_tail = &alt_odb_list;
 377         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 378
 379         read_info_alternates(get_object_directory(), 0);
 380 }
 381
 382 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 383 {
 384         char *name = sha1_file_name(sha1);
 385         struct alternate_object_database *alt;
 386
 387         if (!stat(name, st))
 388                 return name;
 389         prepare_alt_odb();
 390         for (alt = alt_odb_list; alt; alt = alt->next) {
 391                 name = alt->name;
 392                 fill_sha1_path(name, sha1);
 393                 if (!stat(alt->base, st))
 394                         return alt->base;
 395         }
 396         return NULL;
 397 }
 398
 399 #define PACK_MAX_SZ (1<<26)
 400 static int pack_used_ctr;
 401 static unsigned long pack_mapped;
 402 struct packed_git *packed_git;
 403
 404 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 405                                 void **idx_map_)
 406 {
 407         void *idx_map;
 408         unsigned int *index;
 409         unsigned long idx_size;
 410         int nr, i;
 411         int fd = open(path, O_RDONLY);
 412         struct stat st;
 413         if (fd < 0)
 414                 return -1;
 415         if (fstat(fd, &st)) {
 416                 close(fd);
 417                 return -1;
 418         }
 419         idx_size = st.st_size;
 420         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 421         close(fd);
 422         if (idx_map == MAP_FAILED)
 423                 return -1;
 424
 425         index = idx_map;
 426         *idx_map_ = idx_map;
 427         *idx_size_ = idx_size;
 428
 429         /* check index map */
 430         if (idx_size < 4*256 + 20 + 20)
 431                 return error("index file too small");
 432         nr = 0;
 433         for (i = 0; i < 256; i++) {
 434                 unsigned int n = ntohl(index[i]);
 435                 if (n < nr)
 436                         return error("non-monotonic index");
 437                 nr = n;
 438         }
 439
 440         /*
 441          * Total size:
 442          *  - 256 index entries 4 bytes each
 443          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 444          *  - 20-byte SHA1 of the packfile
 445          *  - 20-byte SHA1 file checksum
 446          */
 447         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 448                 return error("wrong index file size");
 449
 450         return 0;
 451 }
 452
 453 static int unuse_one_packed_git(void)
 454 {
 455         struct packed_git *p, *lru = NULL;
 456
 457         for (p = packed_git; p; p = p->next) {
 458                 if (p->pack_use_cnt || !p->pack_base)
 459                         continue;
 460                 if (!lru || p->pack_last_used < lru->pack_last_used)
 461                         lru = p;
 462         }
 463         if (!lru)
 464                 return 0;
 465         munmap(lru->pack_base, lru->pack_size);
 466         lru->pack_base = NULL;
 467         return 1;
 468 }
 469
 470 void unuse_packed_git(struct packed_git *p)
 471 {
 472         p->pack_use_cnt--;
 473 }
 474
 475 int use_packed_git(struct packed_git *p)
 476 {
 477         if (!p->pack_size) {
 478                 struct stat st;
 479                 // We created the struct before we had the pack
 480                 stat(p->pack_name, &st);
 481                 if (!S_ISREG(st.st_mode))
 482                         die("packfile %s not a regular file", p->pack_name);
 483                 p->pack_size = st.st_size;
 484         }
 485         if (!p->pack_base) {
 486                 int fd;
 487                 struct stat st;
 488                 void *map;
 489
 490                 pack_mapped += p->pack_size;
 491                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 492                         ; /* nothing */
 493                 fd = open(p->pack_name, O_RDONLY);
 494                 if (fd < 0)
 495                         die("packfile %s cannot be opened", p->pack_name);
 496                 if (fstat(fd, &st)) {
 497                         close(fd);
 498                         die("packfile %s cannot be opened", p->pack_name);
 499                 }
 500                 if (st.st_size != p->pack_size)
 501                         die("packfile %s size mismatch.", p->pack_name);
 502                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 503                 close(fd);
 504                 if (map == MAP_FAILED)
 505                         die("packfile %s cannot be mapped.", p->pack_name);
 506                 p->pack_base = map;
 507
 508                 /* Check if the pack file matches with the index file.
 509                  * this is cheap.
 510                  */
 511                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 512                            p->pack_base + p->pack_size - 20, 20)) {
 513
 514                         die("packfile %s does not match index.", p->pack_name);
 515                 }
 516         }
 517         p->pack_last_used = pack_used_ctr++;
 518         p->pack_use_cnt++;
 519         return 0;
 520 }
 521
 522 struct packed_git *add_packed_git(char *path, int path_len, int local)
 523 {
 524         struct stat st;
 525         struct packed_git *p;
 526         unsigned long idx_size;
 527         void *idx_map;
 528         unsigned char sha1[20];
 529
 530         if (check_packed_git_idx(path, &idx_size, &idx_map))
 531                 return NULL;
 532
 533         /* do we have a corresponding .pack file? */
 534         strcpy(path + path_len - 4, ".pack");
 535         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 536                 munmap(idx_map, idx_size);
 537                 return NULL;
 538         }
 539         /* ok, it looks sane as far as we can check without
 540          * actually mapping the pack file.
 541          */
 542         p = xmalloc(sizeof(*p) + path_len + 2);
 543         strcpy(p->pack_name, path);
 544         p->index_size = idx_size;
 545         p->pack_size = st.st_size;
 546         p->index_base = idx_map;
 547         p->next = NULL;
 548         p->pack_base = NULL;
 549         p->pack_last_used = 0;
 550         p->pack_use_cnt = 0;
 551         p->pack_local = local;
 552         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 553                 memcpy(p->sha1, sha1, 20);
 554         return p;
 555 }
 556
 557 struct packed_git *parse_pack_index(unsigned char *sha1)
 558 {
 559         char *path = sha1_pack_index_name(sha1);
 560         return parse_pack_index_file(sha1, path);
 561 }
 562
 563 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 564 {
 565         struct packed_git *p;
 566         unsigned long idx_size;
 567         void *idx_map;
 568         char *path;
 569
 570         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 571                 return NULL;
 572
 573         path = sha1_pack_name(sha1);
 574
 575         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 576         strcpy(p->pack_name, path);
 577         p->index_size = idx_size;
 578         p->pack_size = 0;
 579         p->index_base = idx_map;
 580         p->next = NULL;
 581         p->pack_base = NULL;
 582         p->pack_last_used = 0;
 583         p->pack_use_cnt = 0;
 584         memcpy(p->sha1, sha1, 20);
 585         return p;
 586 }
 587
 588 void install_packed_git(struct packed_git *pack)
 589 {
 590         pack->next = packed_git;
 591         packed_git = pack;
 592 }
 593
 594 static void prepare_packed_git_one(char *objdir, int local)
 595 {
 596         char path[PATH_MAX];
 597         int len;
 598         DIR *dir;
 599         struct dirent *de;
 600
 601         sprintf(path, "%s/pack", objdir);
 602         len = strlen(path);
 603         dir = opendir(path);
 604         if (!dir) {
 605                 if (errno != ENOENT)
 606                         error("unable to open object pack directory: %s: %s",
 607                               path, strerror(errno));
 608                 return;
 609         }
 610         path[len++] = '/';
 611         while ((de = readdir(dir)) != NULL) {
 612                 int namelen = strlen(de->d_name);
 613                 struct packed_git *p;
 614
 615                 if (strcmp(de->d_name + namelen - 4, ".idx"))
 616                         continue;
 617
 618                 /* we have .idx.  Is it a file we can map? */
 619                 strcpy(path + len, de->d_name);
 620                 p = add_packed_git(path, len + namelen, local);
 621                 if (!p)
 622                         continue;
 623                 p->next = packed_git;
 624                 packed_git = p;
 625         }
 626         closedir(dir);
 627 }
 628
 629 static int prepare_packed_git_run_once = 0;
 630 void prepare_packed_git(void)
 631 {
 632         struct alternate_object_database *alt;
 633
 634         if (prepare_packed_git_run_once)
 635                 return;
 636         prepare_packed_git_one(get_object_directory(), 1);
 637         prepare_alt_odb();
 638         for (alt = alt_odb_list; alt; alt = alt->next) {
 639                 alt->name[-1] = 0;
 640                 prepare_packed_git_one(alt->base, 0);
 641                 alt->name[-1] = '/';
 642         }
 643         prepare_packed_git_run_once = 1;
 644 }
 645
 646 static void reprepare_packed_git(void)
 647 {
 648         prepare_packed_git_run_once = 0;
 649         prepare_packed_git();
 650 }
 651
 652 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 653 {
 654         char header[100];
 655         unsigned char real_sha1[20];
 656         SHA_CTX c;
 657
 658         SHA1_Init(&c);
 659         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 660         SHA1_Update(&c, map, size);
 661         SHA1_Final(real_sha1, &c);
 662         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 663 }
 664
 665 static void *map_sha1_file_internal(const unsigned char *sha1,
 666                                     unsigned long *size)
 667 {
 668         struct stat st;
 669         void *map;
 670         int fd;
 671         char *filename = find_sha1_file(sha1, &st);
 672
 673         if (!filename) {
 674                 return NULL;
 675         }
 676
 677         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 678         if (fd < 0) {
 679                 /* See if it works without O_NOATIME */
 680                 switch (sha1_file_open_flag) {
 681                 default:
 682                         fd = open(filename, O_RDONLY);
 683                         if (fd >= 0)
 684                                 break;
 685                 /* Fallthrough */
 686                 case 0:
 687                         return NULL;
 688                 }
 689
 690                 /* If it failed once, it will probably fail again.
 691                  * Stop using O_NOATIME
 692                  */
 693                 sha1_file_open_flag = 0;
 694         }
 695         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 696         close(fd);
 697         if (map == MAP_FAILED)
 698                 return NULL;
 699         *size = st.st_size;
 700         return map;
 701 }
 702
 703 int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
 704 {
 705         /* Get the data stream */
 706         memset(stream, 0, sizeof(*stream));
 707         stream->next_in = map;
 708         stream->avail_in = mapsize;
 709         stream->next_out = buffer;
 710         stream->avail_out = size;
 711
 712         inflateInit(stream);
 713         return inflate(stream, 0);
 714 }
 715
 716 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 717 {
 718         int bytes = strlen(buffer) + 1;
 719         unsigned char *buf = xmalloc(1+size);
 720
 721         memcpy(buf, buffer + bytes, stream->total_out - bytes);
 722         bytes = stream->total_out - bytes;
 723         if (bytes < size) {
 724                 stream->next_out = buf + bytes;
 725                 stream->avail_out = size - bytes;
 726                 while (inflate(stream, Z_FINISH) == Z_OK)
 727                         /* nothing */;
 728         }
 729         buf[size] = 0;
 730         inflateEnd(stream);
 731         return buf;
 732 }
 733
 734 /*
 735  * We used to just use "sscanf()", but that's actually way
 736  * too permissive for what we want to check. So do an anal
 737  * object header parse by hand.
 738  */
 739 int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 740 {
 741         int i;
 742         unsigned long size;
 743
 744         /*
 745          * The type can be at most ten bytes (including the
 746          * terminating '\0' that we add), and is followed by
 747          * a space.
 748          */
 749         i = 10;
 750         for (;;) {
 751                 char c = *hdr++;
 752                 if (c == ' ')
 753                         break;
 754                 if (!--i)
 755                         return -1;
 756                 *type++ = c;
 757         }
 758         *type = 0;
 759
 760         /*
 761          * The length must follow immediately, and be in canonical
 762          * decimal format (ie "010" is not valid).
 763          */
 764         size = *hdr++ - '0';
 765         if (size > 9)
 766                 return -1;
 767         if (size) {
 768                 for (;;) {
 769                         unsigned long c = *hdr - '0';
 770                         if (c > 9)
 771                                 break;
 772                         hdr++;
 773                         size = size * 10 + c;
 774                 }
 775         }
 776         *sizep = size;
 777
 778         /*
 779          * The length must be followed by a zero byte
 780          */
 781         return *hdr ? -1 : 0;
 782 }
 783
 784 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 785 {
 786         int ret;
 787         z_stream stream;
 788         char hdr[8192];
 789
 790         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 791         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 792                 return NULL;
 793
 794         return unpack_sha1_rest(&stream, hdr, *size);
 795 }
 796
 797 /* forward declaration for a mutually recursive function */
 798 static int packed_object_info(struct pack_entry *entry,
 799                               char *type, unsigned long *sizep);
 800
 801 static int packed_delta_info(unsigned char *base_sha1,
 802                              unsigned long delta_size,
 803                              unsigned long left,
 804                              char *type,
 805                              unsigned long *sizep,
 806                              struct packed_git *p)
 807 {
 808         struct pack_entry base_ent;
 809
 810         if (left < 20)
 811                 die("truncated pack file");
 812
 813         /* The base entry _must_ be in the same pack */
 814         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 815                 die("failed to find delta-pack base object %s",
 816                     sha1_to_hex(base_sha1));
 817
 818         /* We choose to only get the type of the base object and
 819          * ignore potentially corrupt pack file that expects the delta
 820          * based on a base with a wrong size.  This saves tons of
 821          * inflate() calls.
 822          */
 823
 824         if (packed_object_info(&base_ent, type, NULL))
 825                 die("cannot get info for delta-pack base");
 826
 827         if (sizep) {
 828                 const unsigned char *data;
 829                 unsigned char delta_head[64];
 830                 unsigned long result_size;
 831                 z_stream stream;
 832                 int st;
 833
 834                 memset(&stream, 0, sizeof(stream));
 835
 836                 data = stream.next_in = base_sha1 + 20;
 837                 stream.avail_in = left - 20;
 838                 stream.next_out = delta_head;
 839                 stream.avail_out = sizeof(delta_head);
 840
 841                 inflateInit(&stream);
 842                 st = inflate(&stream, Z_FINISH);
 843                 inflateEnd(&stream);
 844                 if ((st != Z_STREAM_END) &&
 845                     stream.total_out != sizeof(delta_head))
 846                         die("delta data unpack-initial failed");
 847
 848                 /* Examine the initial part of the delta to figure out
 849                  * the result size.
 850                  */
 851                 data = delta_head;
 852
 853                 /* ignore base size */
 854                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 855
 856                 /* Read the result size */
 857                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 858                 *sizep = result_size;
 859         }
 860         return 0;
 861 }
 862
 863 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 864         enum object_type *type, unsigned long *sizep)
 865 {
 866         unsigned shift;
 867         unsigned char *pack, c;
 868         unsigned long size;
 869
 870         if (offset >= p->pack_size)
 871                 die("object offset outside of pack file");
 872
 873         pack =  p->pack_base + offset;
 874         c = *pack++;
 875         offset++;
 876         *type = (c >> 4) & 7;
 877         size = c & 15;
 878         shift = 4;
 879         while (c & 0x80) {
 880                 if (offset >= p->pack_size)
 881                         die("object offset outside of pack file");
 882                 c = *pack++;
 883                 offset++;
 884                 size += (c & 0x7f) << shift;
 885                 shift += 7;
 886         }
 887         *sizep = size;
 888         return offset;
 889 }
 890
 891 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 892                            unsigned char *base, unsigned long *sizep,
 893                            enum object_type *kindp)
 894 {
 895         unsigned long ptr;
 896         int status = -1;
 897
 898         use_packed_git(p);
 899         ptr = offset;
 900         ptr = unpack_object_header(p, ptr, kindp, sizep);
 901         if (*kindp != OBJ_DELTA)
 902                 goto done;
 903         memcpy(base, p->pack_base + ptr, 20);
 904         status = 0;
 905  done:
 906         unuse_packed_git(p);
 907         return status;
 908 }
 909
 910 void packed_object_info_detail(struct pack_entry *e,
 911                                char *type,
 912                                unsigned long *size,
 913                                unsigned long *store_size,
 914                                unsigned int *delta_chain_length,
 915                                unsigned char *base_sha1)
 916 {
 917         struct packed_git *p = e->p;
 918         unsigned long offset;
 919         unsigned char *pack;
 920         enum object_type kind;
 921
 922         offset = unpack_object_header(p, e->offset, &kind, size);
 923         pack = p->pack_base + offset;
 924         if (kind != OBJ_DELTA)
 925                 *delta_chain_length = 0;
 926         else {
 927                 unsigned int chain_length = 0;
 928                 if (p->pack_size <= offset + 20)
 929                         die("pack file %s records an incomplete delta base",
 930                             p->pack_name);
 931                 memcpy(base_sha1, pack, 20);
 932                 do {
 933                         struct pack_entry base_ent;
 934                         unsigned long junk;
 935
 936                         find_pack_entry_one(pack, &base_ent, p);
 937                         offset = unpack_object_header(p, base_ent.offset,
 938                                                       &kind, &junk);
 939                         pack = p->pack_base + offset;
 940                         chain_length++;
 941                 } while (kind == OBJ_DELTA);
 942                 *delta_chain_length = chain_length;
 943         }
 944         switch (kind) {
 945         case OBJ_COMMIT:
 946                 strcpy(type, commit_type);
 947                 break;
 948         case OBJ_TREE:
 949                 strcpy(type, tree_type);
 950                 break;
 951         case OBJ_BLOB:
 952                 strcpy(type, blob_type);
 953                 break;
 954         case OBJ_TAG:
 955                 strcpy(type, tag_type);
 956                 break;
 957         default:
 958                 die("corrupted pack file %s containing object of kind %d",
 959                     p->pack_name, kind);
 960         }
 961         *store_size = 0; /* notyet */
 962 }
 963
 964 static int packed_object_info(struct pack_entry *entry,
 965                               char *type, unsigned long *sizep)
 966 {
 967         struct packed_git *p = entry->p;
 968         unsigned long offset, size, left;
 969         unsigned char *pack;
 970         enum object_type kind;
 971         int retval;
 972
 973         if (use_packed_git(p))
 974                 die("cannot map packed file");
 975
 976         offset = unpack_object_header(p, entry->offset, &kind, &size);
 977         pack = p->pack_base + offset;
 978         left = p->pack_size - offset;
 979
 980         switch (kind) {
 981         case OBJ_DELTA:
 982                 retval = packed_delta_info(pack, size, left, type, sizep, p);
 983                 unuse_packed_git(p);
 984                 return retval;
 985         case OBJ_COMMIT:
 986                 strcpy(type, commit_type);
 987                 break;
 988         case OBJ_TREE:
 989                 strcpy(type, tree_type);
 990                 break;
 991         case OBJ_BLOB:
 992                 strcpy(type, blob_type);
 993                 break;
 994         case OBJ_TAG:
 995                 strcpy(type, tag_type);
 996                 break;
 997         default:
 998                 die("corrupted pack file %s containing object of kind %d",
 999                     p->pack_name, kind);
1000         }
1001         if (sizep)
1002                 *sizep = size;
1003         unuse_packed_git(p);
1004         return 0;
1005 }
1006
1007 /* forward declaration for a mutually recursive function */
1008 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
1009
1010 static void *unpack_delta_entry(unsigned char *base_sha1,
1011                                 unsigned long delta_size,
1012                                 unsigned long left,
1013                                 char *type,
1014                                 unsigned long *sizep,
1015                                 struct packed_git *p)
1016 {
1017         struct pack_entry base_ent;
1018         void *data, *delta_data, *result, *base;
1019         unsigned long data_size, result_size, base_size;
1020         z_stream stream;
1021         int st;
1022
1023         if (left < 20)
1024                 die("truncated pack file");
1025
1026         /* The base entry _must_ be in the same pack */
1027         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1028                 die("failed to find delta-pack base object %s",
1029                     sha1_to_hex(base_sha1));
1030         base = unpack_entry_gently(&base_ent, type, &base_size);
1031         if (!base)
1032                 die("failed to read delta-pack base object %s",
1033                     sha1_to_hex(base_sha1));
1034
1035         data = base_sha1 + 20;
1036         data_size = left - 20;
1037         delta_data = xmalloc(delta_size);
1038
1039         memset(&stream, 0, sizeof(stream));
1040
1041         stream.next_in = data;
1042         stream.avail_in = data_size;
1043         stream.next_out = delta_data;
1044         stream.avail_out = delta_size;
1045
1046         inflateInit(&stream);
1047         st = inflate(&stream, Z_FINISH);
1048         inflateEnd(&stream);
1049         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1050                 die("delta data unpack failed");
1051
1052         result = patch_delta(base, base_size,
1053                              delta_data, delta_size,
1054                              &result_size);
1055         if (!result)
1056                 die("failed to apply delta");
1057         free(delta_data);
1058         free(base);
1059         *sizep = result_size;
1060         return result;
1061 }
1062
1063 static void *unpack_non_delta_entry(unsigned char *data,
1064                                     unsigned long size,
1065                                     unsigned long left)
1066 {
1067         int st;
1068         z_stream stream;
1069         unsigned char *buffer;
1070
1071         buffer = xmalloc(size + 1);
1072         buffer[size] = 0;
1073         memset(&stream, 0, sizeof(stream));
1074         stream.next_in = data;
1075         stream.avail_in = left;
1076         stream.next_out = buffer;
1077         stream.avail_out = size;
1078
1079         inflateInit(&stream);
1080         st = inflate(&stream, Z_FINISH);
1081         inflateEnd(&stream);
1082         if ((st != Z_STREAM_END) || stream.total_out != size) {
1083                 free(buffer);
1084                 return NULL;
1085         }
1086
1087         return buffer;
1088 }
1089
1090 static void *unpack_entry(struct pack_entry *entry,
1091                           char *type, unsigned long *sizep)
1092 {
1093         struct packed_git *p = entry->p;
1094         void *retval;
1095
1096         if (use_packed_git(p))
1097                 die("cannot map packed file");
1098         retval = unpack_entry_gently(entry, type, sizep);
1099         unuse_packed_git(p);
1100         if (!retval)
1101                 die("corrupted pack file %s", p->pack_name);
1102         return retval;
1103 }
1104
1105 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1106 void *unpack_entry_gently(struct pack_entry *entry,
1107                           char *type, unsigned long *sizep)
1108 {
1109         struct packed_git *p = entry->p;
1110         unsigned long offset, size, left;
1111         unsigned char *pack;
1112         enum object_type kind;
1113         void *retval;
1114
1115         offset = unpack_object_header(p, entry->offset, &kind, &size);
1116         pack = p->pack_base + offset;
1117         left = p->pack_size - offset;
1118         switch (kind) {
1119         case OBJ_DELTA:
1120                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1121                 return retval;
1122         case OBJ_COMMIT:
1123                 strcpy(type, commit_type);
1124                 break;
1125         case OBJ_TREE:
1126                 strcpy(type, tree_type);
1127                 break;
1128         case OBJ_BLOB:
1129                 strcpy(type, blob_type);
1130                 break;
1131         case OBJ_TAG:
1132                 strcpy(type, tag_type);
1133                 break;
1134         default:
1135                 return NULL;
1136         }
1137         *sizep = size;
1138         retval = unpack_non_delta_entry(pack, size, left);
1139         return retval;
1140 }
1141
1142 int num_packed_objects(const struct packed_git *p)
1143 {
1144         /* See check_packed_git_idx() */
1145         return (p->index_size - 20 - 20 - 4*256) / 24;
1146 }
1147
1148 int nth_packed_object_sha1(const struct packed_git *p, int n,
1149                            unsigned char* sha1)
1150 {
1151         void *index = p->index_base + 256;
1152         if (n < 0 || num_packed_objects(p) <= n)
1153                 return -1;
1154         memcpy(sha1, (index + 24 * n + 4), 20);
1155         return 0;
1156 }
1157
1158 int find_pack_entry_one(const unsigned char *sha1,
1159                         struct pack_entry *e, struct packed_git *p)
1160 {
1161         unsigned int *level1_ofs = p->index_base;
1162         int hi = ntohl(level1_ofs[*sha1]);
1163         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1164         void *index = p->index_base + 256;
1165
1166         do {
1167                 int mi = (lo + hi) / 2;
1168                 int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
1169                 if (!cmp) {
1170                         e->offset = ntohl(*((unsigned int *)(index + 24 * mi)));
1171                         memcpy(e->sha1, sha1, 20);
1172                         e->p = p;
1173                         return 1;
1174                 }
1175                 if (cmp > 0)
1176                         hi = mi;
1177                 else
1178                         lo = mi+1;
1179         } while (lo < hi);
1180         return 0;
1181 }
1182
1183 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1184 {
1185         struct packed_git *p;
1186         prepare_packed_git();
1187
1188         for (p = packed_git; p; p = p->next) {
1189                 if (find_pack_entry_one(sha1, e, p))
1190                         return 1;
1191         }
1192         return 0;
1193 }
1194
1195 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1196                                   struct packed_git *packs)
1197 {
1198         struct packed_git *p;
1199         struct pack_entry e;
1200
1201         for (p = packs; p; p = p->next) {
1202                 if (find_pack_entry_one(sha1, &e, p))
1203                         return p;
1204         }
1205         return NULL;
1206
1207 }
1208
1209 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1210 {
1211         int status;
1212         unsigned long mapsize, size;
1213         void *map;
1214         z_stream stream;
1215         char hdr[128];
1216
1217         map = map_sha1_file_internal(sha1, &mapsize);
1218         if (!map) {
1219                 struct pack_entry e;
1220
1221                 if (find_pack_entry(sha1, &e))
1222                         return packed_object_info(&e, type, sizep);
1223                 reprepare_packed_git();
1224                 if (find_pack_entry(sha1, &e))
1225                         return packed_object_info(&e, type, sizep);
1226                 return error("unable to find %s", sha1_to_hex(sha1));
1227         }
1228         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1229                 status = error("unable to unpack %s header",
1230                                sha1_to_hex(sha1));
1231         if (parse_sha1_header(hdr, type, &size) < 0)
1232                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1233         else {
1234                 status = 0;
1235                 if (sizep)
1236                         *sizep = size;
1237         }
1238         inflateEnd(&stream);
1239         munmap(map, mapsize);
1240         return status;
1241 }
1242
1243 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1244 {
1245         struct pack_entry e;
1246
1247         if (!find_pack_entry(sha1, &e)) {
1248                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1249                 return NULL;
1250         }
1251         return unpack_entry(&e, type, size);
1252 }
1253
1254 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1255 {
1256         unsigned long mapsize;
1257         void *map, *buf;
1258         struct pack_entry e;
1259
1260         if (find_pack_entry(sha1, &e))
1261                 return read_packed_sha1(sha1, type, size);
1262         map = map_sha1_file_internal(sha1, &mapsize);
1263         if (map) {
1264                 buf = unpack_sha1_file(map, mapsize, type, size);
1265                 munmap(map, mapsize);
1266                 return buf;
1267         }
1268         reprepare_packed_git();
1269         if (find_pack_entry(sha1, &e))
1270                 return read_packed_sha1(sha1, type, size);
1271         return NULL;
1272 }
1273
1274 void *read_object_with_reference(const unsigned char *sha1,
1275                                  const char *required_type,
1276                                  unsigned long *size,
1277                                  unsigned char *actual_sha1_return)
1278 {
1279         char type[20];
1280         void *buffer;
1281         unsigned long isize;
1282         unsigned char actual_sha1[20];
1283
1284         memcpy(actual_sha1, sha1, 20);
1285         while (1) {
1286                 int ref_length = -1;
1287                 const char *ref_type = NULL;
1288
1289                 buffer = read_sha1_file(actual_sha1, type, &isize);
1290                 if (!buffer)
1291                         return NULL;
1292                 if (!strcmp(type, required_type)) {
1293                         *size = isize;
1294                         if (actual_sha1_return)
1295                                 memcpy(actual_sha1_return, actual_sha1, 20);
1296                         return buffer;
1297                 }
1298                 /* Handle references */
1299                 else if (!strcmp(type, commit_type))
1300                         ref_type = "tree ";
1301                 else if (!strcmp(type, tag_type))
1302                         ref_type = "object ";
1303                 else {
1304                         free(buffer);
1305                         return NULL;
1306                 }
1307                 ref_length = strlen(ref_type);
1308
1309                 if (memcmp(buffer, ref_type, ref_length) ||
1310                     get_sha1_hex(buffer + ref_length, actual_sha1)) {
1311                         free(buffer);
1312                         return NULL;
1313                 }
1314                 free(buffer);
1315                 /* Now we have the ID of the referred-to object in
1316                  * actual_sha1.  Check again. */
1317         }
1318 }
1319
1320 char *write_sha1_file_prepare(void *buf,
1321                               unsigned long len,
1322                               const char *type,
1323                               unsigned char *sha1,
1324                               unsigned char *hdr,
1325                               int *hdrlen)
1326 {
1327         SHA_CTX c;
1328
1329         /* Generate the header */
1330         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1331
1332         /* Sha1.. */
1333         SHA1_Init(&c);
1334         SHA1_Update(&c, hdr, *hdrlen);
1335         SHA1_Update(&c, buf, len);
1336         SHA1_Final(sha1, &c);
1337
1338         return sha1_file_name(sha1);
1339 }
1340
1341 /*
1342  * Link the tempfile to the final place, possibly creating the
1343  * last directory level as you do so.
1344  *
1345  * Returns the errno on failure, 0 on success.
1346  */
1347 static int link_temp_to_file(const char *tmpfile, char *filename)
1348 {
1349         int ret;
1350
1351         if (!link(tmpfile, filename))
1352                 return 0;
1353
1354         /*
1355          * Try to mkdir the last path component if that failed
1356          * with an ENOENT.
1357          *
1358          * Re-try the "link()" regardless of whether the mkdir
1359          * succeeds, since a race might mean that somebody
1360          * else succeeded.
1361          */
1362         ret = errno;
1363         if (ret == ENOENT) {
1364                 char *dir = strrchr(filename, '/');
1365                 if (dir) {
1366                         *dir = 0;
1367                         mkdir(filename, 0777);
1368                         if (adjust_shared_perm(filename))
1369                                 return -2;
1370                         *dir = '/';
1371                         if (!link(tmpfile, filename))
1372                                 return 0;
1373                         ret = errno;
1374                 }
1375         }
1376         return ret;
1377 }
1378
1379 /*
1380  * Move the just written object into its final resting place
1381  */
1382 int move_temp_to_file(const char *tmpfile, char *filename)
1383 {
1384         int ret = link_temp_to_file(tmpfile, filename);
1385
1386         /*
1387          * Coda hack - coda doesn't like cross-directory links,
1388          * so we fall back to a rename, which will mean that it
1389          * won't be able to check collisions, but that's not a
1390          * big deal.
1391          *
1392          * The same holds for FAT formatted media.
1393          *
1394          * When this succeeds, we just return 0. We have nothing
1395          * left to unlink.
1396          */
1397         if (ret && ret != EEXIST) {
1398                 if (!rename(tmpfile, filename))
1399                         return 0;
1400                 ret = errno;
1401         }
1402         unlink(tmpfile);
1403         if (ret) {
1404                 if (ret != EEXIST) {
1405                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1406                         return -1;
1407                 }
1408                 /* FIXME!!! Collision check here ? */
1409         }
1410
1411         return 0;
1412 }
1413
1414 static int write_buffer(int fd, const void *buf, size_t len)
1415 {
1416         while (len) {
1417                 ssize_t size;
1418
1419                 size = write(fd, buf, len);
1420                 if (!size)
1421                         return error("file write: disk full");
1422                 if (size < 0) {
1423                         if (errno == EINTR || errno == EAGAIN)
1424                                 continue;
1425                         return error("file write error (%s)", strerror(errno));
1426                 }
1427                 len -= size;
1428                 buf += size;
1429         }
1430         return 0;
1431 }
1432
1433 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1434 {
1435         int size;
1436         unsigned char *compressed;
1437         z_stream stream;
1438         unsigned char sha1[20];
1439         char *filename;
1440         static char tmpfile[PATH_MAX];
1441         unsigned char hdr[50];
1442         int fd, hdrlen;
1443
1444         /* Normally if we have it in the pack then we do not bother writing
1445          * it out into .git/objects/??/?{38} file.
1446          */
1447         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1448         if (returnsha1)
1449                 memcpy(returnsha1, sha1, 20);
1450         if (has_sha1_file(sha1))
1451                 return 0;
1452         fd = open(filename, O_RDONLY);
1453         if (fd >= 0) {
1454                 /*
1455                  * FIXME!!! We might do collision checking here, but we'd
1456                  * need to uncompress the old file and check it. Later.
1457                  */
1458                 close(fd);
1459                 return 0;
1460         }
1461
1462         if (errno != ENOENT) {
1463                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1464                 return -1;
1465         }
1466
1467         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1468
1469         fd = mkstemp(tmpfile);
1470         if (fd < 0) {
1471                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1472                 return -1;
1473         }
1474
1475         /* Set it up */
1476         memset(&stream, 0, sizeof(stream));
1477         deflateInit(&stream, Z_BEST_COMPRESSION);
1478         size = deflateBound(&stream, len+hdrlen);
1479         compressed = xmalloc(size);
1480
1481         /* Compress it */
1482         stream.next_out = compressed;
1483         stream.avail_out = size;
1484
1485         /* First header.. */
1486         stream.next_in = hdr;
1487         stream.avail_in = hdrlen;
1488         while (deflate(&stream, 0) == Z_OK)
1489                 /* nothing */;
1490
1491         /* Then the data itself.. */
1492         stream.next_in = buf;
1493         stream.avail_in = len;
1494         while (deflate(&stream, Z_FINISH) == Z_OK)
1495                 /* nothing */;
1496         deflateEnd(&stream);
1497         size = stream.total_out;
1498
1499         if (write_buffer(fd, compressed, size) < 0)
1500                 die("unable to write sha1 file");
1501         fchmod(fd, 0444);
1502         close(fd);
1503         free(compressed);
1504
1505         return move_temp_to_file(tmpfile, filename);
1506 }
1507
1508 /*
1509  * We need to unpack and recompress the object for writing
1510  * it out to a different file.
1511  */
1512 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1513 {
1514         size_t size;
1515         z_stream stream;
1516         unsigned char *unpacked;
1517         unsigned long len;
1518         char type[20];
1519         char hdr[50];
1520         int hdrlen;
1521         void *buf;
1522
1523         // need to unpack and recompress it by itself
1524         unpacked = read_packed_sha1(sha1, type, &len);
1525
1526         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1527
1528         /* Set it up */
1529         memset(&stream, 0, sizeof(stream));
1530         deflateInit(&stream, Z_BEST_COMPRESSION);
1531         size = deflateBound(&stream, len + hdrlen);
1532         buf = xmalloc(size);
1533
1534         /* Compress it */
1535         stream.next_out = buf;
1536         stream.avail_out = size;
1537
1538         /* First header.. */
1539         stream.next_in = (void *)hdr;
1540         stream.avail_in = hdrlen;
1541         while (deflate(&stream, 0) == Z_OK)
1542                 /* nothing */;
1543
1544         /* Then the data itself.. */
1545         stream.next_in = unpacked;
1546         stream.avail_in = len;
1547         while (deflate(&stream, Z_FINISH) == Z_OK)
1548                 /* nothing */;
1549         deflateEnd(&stream);
1550         free(unpacked);
1551
1552         *objsize = stream.total_out;
1553         return buf;
1554 }
1555
1556 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1557 {
1558         int retval;
1559         unsigned long objsize;
1560         void *buf = map_sha1_file_internal(sha1, &objsize);
1561
1562         if (buf) {
1563                 retval = write_buffer(fd, buf, objsize);
1564                 munmap(buf, objsize);
1565                 return retval;
1566         }
1567
1568         buf = repack_object(sha1, &objsize);
1569         retval = write_buffer(fd, buf, objsize);
1570         free(buf);
1571         return retval;
1572 }
1573
1574 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1575                        size_t bufsize, size_t *bufposn)
1576 {
1577         char tmpfile[PATH_MAX];
1578         int local;
1579         z_stream stream;
1580         unsigned char real_sha1[20];
1581         unsigned char discard[4096];
1582         int ret;
1583         SHA_CTX c;
1584
1585         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1586
1587         local = mkstemp(tmpfile);
1588         if (local < 0)
1589                 return error("Couldn't open %s for %s",
1590                              tmpfile, sha1_to_hex(sha1));
1591
1592         memset(&stream, 0, sizeof(stream));
1593
1594         inflateInit(&stream);
1595
1596         SHA1_Init(&c);
1597
1598         do {
1599                 ssize_t size;
1600                 if (*bufposn) {
1601                         stream.avail_in = *bufposn;
1602                         stream.next_in = (unsigned char *) buffer;
1603                         do {
1604                                 stream.next_out = discard;
1605                                 stream.avail_out = sizeof(discard);
1606                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1607                                 SHA1_Update(&c, discard, sizeof(discard) -
1608                                             stream.avail_out);
1609                         } while (stream.avail_in && ret == Z_OK);
1610                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1611                                 die("unable to write sha1 file");
1612                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1613                                 stream.avail_in);
1614                         *bufposn = stream.avail_in;
1615                         if (ret != Z_OK)
1616                                 break;
1617                 }
1618                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1619                 if (size <= 0) {
1620                         close(local);
1621                         unlink(tmpfile);
1622                         if (!size)
1623                                 return error("Connection closed?");
1624                         perror("Reading from connection");
1625                         return -1;
1626                 }
1627                 *bufposn += size;
1628         } while (1);
1629         inflateEnd(&stream);
1630
1631         close(local);
1632         SHA1_Final(real_sha1, &c);
1633         if (ret != Z_STREAM_END) {
1634                 unlink(tmpfile);
1635                 return error("File %s corrupted", sha1_to_hex(sha1));
1636         }
1637         if (memcmp(sha1, real_sha1, 20)) {
1638                 unlink(tmpfile);
1639                 return error("File %s has bad hash", sha1_to_hex(sha1));
1640         }
1641
1642         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1643 }
1644
1645 int has_pack_index(const unsigned char *sha1)
1646 {
1647         struct stat st;
1648         if (stat(sha1_pack_index_name(sha1), &st))
1649                 return 0;
1650         return 1;
1651 }
1652
1653 int has_pack_file(const unsigned char *sha1)
1654 {
1655         struct stat st;
1656         if (stat(sha1_pack_name(sha1), &st))
1657                 return 0;
1658         return 1;
1659 }
1660
1661 int has_sha1_pack(const unsigned char *sha1)
1662 {
1663         struct pack_entry e;
1664         return find_pack_entry(sha1, &e);
1665 }
1666
1667 int has_sha1_file(const unsigned char *sha1)
1668 {
1669         struct stat st;
1670         struct pack_entry e;
1671
1672         if (find_pack_entry(sha1, &e))
1673                 return 1;
1674         return find_sha1_file(sha1, &st) ? 1 : 0;
1675 }
1676
1677 /*
1678  * reads from fd as long as possible into a supplied buffer of size bytes.
1679  * If neccessary the buffer's size is increased using realloc()
1680  *
1681  * returns 0 if anything went fine and -1 otherwise
1682  *
1683  * NOTE: both buf and size may change, but even when -1 is returned
1684  * you still have to free() it yourself.
1685  */
1686 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1687 {
1688         char* buf = *return_buf;
1689         unsigned long size = *return_size;
1690         int iret;
1691         unsigned long off = 0;
1692
1693         do {
1694                 iret = xread(fd, buf + off, size - off);
1695                 if (iret > 0) {
1696                         off += iret;
1697                         if (off == size) {
1698                                 size *= 2;
1699                                 buf = realloc(buf, size);
1700                         }
1701                 }
1702         } while (iret > 0);
1703
1704         *return_buf = buf;
1705         *return_size = off;
1706
1707         if (iret < 0)
1708                 return -1;
1709         return 0;
1710 }
1711
1712 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1713 {
1714         unsigned long size = 4096;
1715         char *buf = malloc(size);
1716         int ret;
1717         unsigned char hdr[50];
1718         int hdrlen;
1719
1720         if (read_pipe(fd, &buf, &size)) {
1721                 free(buf);
1722                 return -1;
1723         }
1724
1725         if (!type)
1726                 type = blob_type;
1727         if (write_object)
1728                 ret = write_sha1_file(buf, size, type, sha1);
1729         else {
1730                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1731                 ret = 0;
1732         }
1733         free(buf);
1734         return ret;
1735 }
1736
1737 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1738 {
1739         unsigned long size = st->st_size;
1740         void *buf;
1741         int ret;
1742         unsigned char hdr[50];
1743         int hdrlen;
1744
1745         buf = "";
1746         if (size)
1747                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1748         close(fd);
1749         if (buf == MAP_FAILED)
1750                 return -1;
1751
1752         if (!type)
1753                 type = blob_type;
1754         if (write_object)
1755                 ret = write_sha1_file(buf, size, type, sha1);
1756         else {
1757                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1758                 ret = 0;
1759         }
1760         if (size)
1761                 munmap(buf, size);
1762         return ret;
1763 }
1764
1765 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1766 {
1767         int fd;
1768         char *target;
1769
1770         switch (st->st_mode & S_IFMT) {
1771         case S_IFREG:
1772                 fd = open(path, O_RDONLY);
1773                 if (fd < 0)
1774                         return error("open(\"%s\"): %s", path,
1775                                      strerror(errno));
1776                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1777                         return error("%s: failed to insert into database",
1778                                      path);
1779                 break;
1780         case S_IFLNK:
1781                 target = xmalloc(st->st_size+1);
1782                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1783                         char *errstr = strerror(errno);
1784                         free(target);
1785                         return error("readlink(\"%s\"): %s", path,
1786                                      errstr);
1787                 }
1788                 if (!write_object) {
1789                         unsigned char hdr[50];
1790                         int hdrlen;
1791                         write_sha1_file_prepare(target, st->st_size, blob_type,
1792                                                 sha1, hdr, &hdrlen);
1793                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1794                         return error("%s: failed to insert into database",
1795                                      path);
1796                 free(target);
1797                 break;
1798         default:
1799                 return error("%s: unsupported file type", path);
1800         }
1801         return 0;
1802 }