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 safe_create_leading_directories(char *path)
  54 {
  55         char *pos = path;
  56         struct stat st;
  57
  58         if (*pos == '/')
  59                 pos++;
  60
  61         while (pos) {
  62                 pos = strchr(pos, '/');
  63                 if (!pos)
  64                         break;
  65                 *pos = 0;
  66                 if (!stat(path, &st)) {
  67                         /* path exists */
  68                         if (!S_ISDIR(st.st_mode)) {
  69                                 *pos = '/';
  70                                 return -3;
  71                         }
  72                 }
  73                 else if (mkdir(path, 0777)) {
  74                         *pos = '/';
  75                         return -1;
  76                 }
  77                 else if (adjust_shared_perm(path)) {
  78                         *pos = '/';
  79                         return -2;
  80                 }
  81                 *pos++ = '/';
  82         }
  83         return 0;
  84 }
  85
  86 char * sha1_to_hex(const unsigned char *sha1)
  87 {
  88         static int bufno;
  89         static char hexbuffer[4][50];
  90         static const char hex[] = "0123456789abcdef";
  91         char *buffer = hexbuffer[3 & ++bufno], *buf = buffer;
  92         int i;
  93
  94         for (i = 0; i < 20; i++) {
  95                 unsigned int val = *sha1++;
  96                 *buf++ = hex[val >> 4];
  97                 *buf++ = hex[val & 0xf];
  98         }
  99         *buf = '\0';
 100
 101         return buffer;
 102 }
 103
 104 static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 105 {
 106         int i;
 107         for (i = 0; i < 20; i++) {
 108                 static char hex[] = "0123456789abcdef";
 109                 unsigned int val = sha1[i];
 110                 char *pos = pathbuf + i*2 + (i > 0);
 111                 *pos++ = hex[val >> 4];
 112                 *pos = hex[val & 0xf];
 113         }
 114 }
 115
 116 /*
 117  * NOTE! This returns a statically allocated buffer, so you have to be
 118  * careful about using it. Do a "strdup()" if you need to save the
 119  * filename.
 120  *
 121  * Also note that this returns the location for creating.  Reading
 122  * SHA1 file can happen from any alternate directory listed in the
 123  * DB_ENVIRONMENT environment variable if it is not found in
 124  * the primary object database.
 125  */
 126 char *sha1_file_name(const unsigned char *sha1)
 127 {
 128         static char *name, *base;
 129
 130         if (!base) {
 131                 const char *sha1_file_directory = get_object_directory();
 132                 int len = strlen(sha1_file_directory);
 133                 base = xmalloc(len + 60);
 134                 memcpy(base, sha1_file_directory, len);
 135                 memset(base+len, 0, 60);
 136                 base[len] = '/';
 137                 base[len+3] = '/';
 138                 name = base + len + 1;
 139         }
 140         fill_sha1_path(name, sha1);
 141         return base;
 142 }
 143
 144 char *sha1_pack_name(const unsigned char *sha1)
 145 {
 146         static const char hex[] = "0123456789abcdef";
 147         static char *name, *base, *buf;
 148         int i;
 149
 150         if (!base) {
 151                 const char *sha1_file_directory = get_object_directory();
 152                 int len = strlen(sha1_file_directory);
 153                 base = xmalloc(len + 60);
 154                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
 155                 name = base + len + 11;
 156         }
 157
 158         buf = name;
 159
 160         for (i = 0; i < 20; i++) {
 161                 unsigned int val = *sha1++;
 162                 *buf++ = hex[val >> 4];
 163                 *buf++ = hex[val & 0xf];
 164         }
 165
 166         return base;
 167 }
 168
 169 char *sha1_pack_index_name(const unsigned char *sha1)
 170 {
 171         static const char hex[] = "0123456789abcdef";
 172         static char *name, *base, *buf;
 173         int i;
 174
 175         if (!base) {
 176                 const char *sha1_file_directory = get_object_directory();
 177                 int len = strlen(sha1_file_directory);
 178                 base = xmalloc(len + 60);
 179                 sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
 180                 name = base + len + 11;
 181         }
 182
 183         buf = name;
 184
 185         for (i = 0; i < 20; i++) {
 186                 unsigned int val = *sha1++;
 187                 *buf++ = hex[val >> 4];
 188                 *buf++ = hex[val & 0xf];
 189         }
 190
 191         return base;
 192 }
 193
 194 struct alternate_object_database *alt_odb_list;
 195 static struct alternate_object_database **alt_odb_tail;
 196
 197 static void read_info_alternates(const char * alternates, int depth);
 198
 199 /*
 200  * Prepare alternate object database registry.
 201  *
 202  * The variable alt_odb_list points at the list of struct
 203  * alternate_object_database.  The elements on this list come from
 204  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 205  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 206  * whose contents is similar to that environment variable but can be
 207  * LF separated.  Its base points at a statically allocated buffer that
 208  * contains "/the/directory/corresponding/to/.git/objects/...", while
 209  * its name points just after the slash at the end of ".git/objects/"
 210  * in the example above, and has enough space to hold 40-byte hex
 211  * SHA1, an extra slash for the first level indirection, and the
 212  * terminating NUL.
 213  */
 214 static int link_alt_odb_entry(const char * entry, int len, const char * relative_base, int depth)
 215 {
 216         struct stat st;
 217         const char *objdir = get_object_directory();
 218         struct alternate_object_database *ent;
 219         struct alternate_object_database *alt;
 220         /* 43 = 40-byte + 2 '/' + terminating NUL */
 221         int pfxlen = len;
 222         int entlen = pfxlen + 43;
 223         int base_len = -1;
 224
 225         if (*entry != '/' && relative_base) {
 226                 /* Relative alt-odb */
 227                 if (base_len < 0)
 228                         base_len = strlen(relative_base) + 1;
 229                 entlen += base_len;
 230                 pfxlen += base_len;
 231         }
 232         ent = xmalloc(sizeof(*ent) + entlen);
 233
 234         if (*entry != '/' && relative_base) {
 235                 memcpy(ent->base, relative_base, base_len - 1);
 236                 ent->base[base_len - 1] = '/';
 237                 memcpy(ent->base + base_len, entry, len);
 238         }
 239         else
 240                 memcpy(ent->base, entry, pfxlen);
 241
 242         ent->name = ent->base + pfxlen + 1;
 243         ent->base[pfxlen + 3] = '/';
 244         ent->base[pfxlen] = ent->base[entlen-1] = 0;
 245
 246         /* Detect cases where alternate disappeared */
 247         if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
 248                 error("object directory %s does not exist; "
 249                       "check .git/objects/info/alternates.",
 250                       ent->base);
 251                 free(ent);
 252                 return -1;
 253         }
 254
 255         /* Prevent the common mistake of listing the same
 256          * thing twice, or object directory itself.
 257          */
 258         for (alt = alt_odb_list; alt; alt = alt->next) {
 259                 if (!memcmp(ent->base, alt->base, pfxlen)) {
 260                         free(ent);
 261                         return -1;
 262                 }
 263         }
 264         if (!memcmp(ent->base, objdir, pfxlen)) {
 265                 free(ent);
 266                 return -1;
 267         }
 268
 269         /* add the alternate entry */
 270         *alt_odb_tail = ent;
 271         alt_odb_tail = &(ent->next);
 272         ent->next = NULL;
 273
 274         /* recursively add alternates */
 275         read_info_alternates(ent->base, depth + 1);
 276
 277         ent->base[pfxlen] = '/';
 278
 279         return 0;
 280 }
 281
 282 static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
 283                                  const char *relative_base, int depth)
 284 {
 285         const char *cp, *last;
 286
 287         if (depth > 5) {
 288                 error("%s: ignoring alternate object stores, nesting too deep.",
 289                                 relative_base);
 290                 return;
 291         }
 292
 293         last = alt;
 294         while (last < ep) {
 295                 cp = last;
 296                 if (cp < ep && *cp == '#') {
 297                         while (cp < ep && *cp != sep)
 298                                 cp++;
 299                         last = cp + 1;
 300                         continue;
 301                 }
 302                 while (cp < ep && *cp != sep)
 303                         cp++;
 304                 if (last != cp) {
 305                         if ((*last != '/') && depth) {
 306                                 error("%s: ignoring relative alternate object store %s",
 307                                                 relative_base, last);
 308                         } else {
 309                                 link_alt_odb_entry(last, cp - last,
 310                                                 relative_base, depth);
 311                         }
 312                 }
 313                 while (cp < ep && *cp == sep)
 314                         cp++;
 315                 last = cp;
 316         }
 317 }
 318
 319 static void read_info_alternates(const char * relative_base, int depth)
 320 {
 321         char *map;
 322         struct stat st;
 323         char path[PATH_MAX];
 324         int fd;
 325
 326         sprintf(path, "%s/info/alternates", relative_base);
 327         fd = open(path, O_RDONLY);
 328         if (fd < 0)
 329                 return;
 330         if (fstat(fd, &st) || (st.st_size == 0)) {
 331                 close(fd);
 332                 return;
 333         }
 334         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 335         close(fd);
 336         if (map == MAP_FAILED)
 337                 return;
 338
 339         link_alt_odb_entries(map, map + st.st_size, '\n', relative_base, depth);
 340
 341         munmap(map, st.st_size);
 342 }
 343
 344 void prepare_alt_odb(void)
 345 {
 346         const char *alt;
 347
 348         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 349         if (!alt) alt = "";
 350
 351         if (alt_odb_tail)
 352                 return;
 353         alt_odb_tail = &alt_odb_list;
 354         link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL, 0);
 355
 356         read_info_alternates(get_object_directory(), 0);
 357 }
 358
 359 static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
 360 {
 361         char *name = sha1_file_name(sha1);
 362         struct alternate_object_database *alt;
 363
 364         if (!stat(name, st))
 365                 return name;
 366         prepare_alt_odb();
 367         for (alt = alt_odb_list; alt; alt = alt->next) {
 368                 name = alt->name;
 369                 fill_sha1_path(name, sha1);
 370                 if (!stat(alt->base, st))
 371                         return alt->base;
 372         }
 373         return NULL;
 374 }
 375
 376 #define PACK_MAX_SZ (1<<26)
 377 static int pack_used_ctr;
 378 static unsigned long pack_mapped;
 379 struct packed_git *packed_git;
 380
 381 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 382                                 void **idx_map_)
 383 {
 384         void *idx_map;
 385         unsigned int *index;
 386         unsigned long idx_size;
 387         int nr, i;
 388         int fd = open(path, O_RDONLY);
 389         struct stat st;
 390         if (fd < 0)
 391                 return -1;
 392         if (fstat(fd, &st)) {
 393                 close(fd);
 394                 return -1;
 395         }
 396         idx_size = st.st_size;
 397         idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 398         close(fd);
 399         if (idx_map == MAP_FAILED)
 400                 return -1;
 401
 402         index = idx_map;
 403         *idx_map_ = idx_map;
 404         *idx_size_ = idx_size;
 405
 406         /* check index map */
 407         if (idx_size < 4*256 + 20 + 20)
 408                 return error("index file too small");
 409         nr = 0;
 410         for (i = 0; i < 256; i++) {
 411                 unsigned int n = ntohl(index[i]);
 412                 if (n < nr)
 413                         return error("non-monotonic index");
 414                 nr = n;
 415         }
 416
 417         /*
 418          * Total size:
 419          *  - 256 index entries 4 bytes each
 420          *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 421          *  - 20-byte SHA1 of the packfile
 422          *  - 20-byte SHA1 file checksum
 423          */
 424         if (idx_size != 4*256 + nr * 24 + 20 + 20)
 425                 return error("wrong index file size");
 426
 427         return 0;
 428 }
 429
 430 static int unuse_one_packed_git(void)
 431 {
 432         struct packed_git *p, *lru = NULL;
 433
 434         for (p = packed_git; p; p = p->next) {
 435                 if (p->pack_use_cnt || !p->pack_base)
 436                         continue;
 437                 if (!lru || p->pack_last_used < lru->pack_last_used)
 438                         lru = p;
 439         }
 440         if (!lru)
 441                 return 0;
 442         munmap(lru->pack_base, lru->pack_size);
 443         lru->pack_base = NULL;
 444         return 1;
 445 }
 446
 447 void unuse_packed_git(struct packed_git *p)
 448 {
 449         p->pack_use_cnt--;
 450 }
 451
 452 int use_packed_git(struct packed_git *p)
 453 {
 454         if (!p->pack_size) {
 455                 struct stat st;
 456                 /* We created the struct before we had the pack */
 457                 stat(p->pack_name, &st);
 458                 if (!S_ISREG(st.st_mode))
 459                         die("packfile %s not a regular file", p->pack_name);
 460                 p->pack_size = st.st_size;
 461         }
 462         if (!p->pack_base) {
 463                 int fd;
 464                 struct stat st;
 465                 void *map;
 466
 467                 pack_mapped += p->pack_size;
 468                 while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
 469                         ; /* nothing */
 470                 fd = open(p->pack_name, O_RDONLY);
 471                 if (fd < 0)
 472                         die("packfile %s cannot be opened", p->pack_name);
 473                 if (fstat(fd, &st)) {
 474                         close(fd);
 475                         die("packfile %s cannot be opened", p->pack_name);
 476                 }
 477                 if (st.st_size != p->pack_size)
 478                         die("packfile %s size mismatch.", p->pack_name);
 479                 map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
 480                 close(fd);
 481                 if (map == MAP_FAILED)
 482                         die("packfile %s cannot be mapped.", p->pack_name);
 483                 p->pack_base = map;
 484
 485                 /* Check if the pack file matches with the index file.
 486                  * this is cheap.
 487                  */
 488                 if (memcmp((char*)(p->index_base) + p->index_size - 40,
 489                            (char *) p->pack_base + p->pack_size - 20,
 490                            20)) {
 491
 492                         die("packfile %s does not match index.", p->pack_name);
 493                 }
 494         }
 495         p->pack_last_used = pack_used_ctr++;
 496         p->pack_use_cnt++;
 497         return 0;
 498 }
 499
 500 struct packed_git *add_packed_git(char *path, int path_len, int local)
 501 {
 502         struct stat st;
 503         struct packed_git *p;
 504         unsigned long idx_size;
 505         void *idx_map;
 506         unsigned char sha1[20];
 507
 508         if (check_packed_git_idx(path, &idx_size, &idx_map))
 509                 return NULL;
 510
 511         /* do we have a corresponding .pack file? */
 512         strcpy(path + path_len - 4, ".pack");
 513         if (stat(path, &st) || !S_ISREG(st.st_mode)) {
 514                 munmap(idx_map, idx_size);
 515                 return NULL;
 516         }
 517         /* ok, it looks sane as far as we can check without
 518          * actually mapping the pack file.
 519          */
 520         p = xmalloc(sizeof(*p) + path_len + 2);
 521         strcpy(p->pack_name, path);
 522         p->index_size = idx_size;
 523         p->pack_size = st.st_size;
 524         p->index_base = idx_map;
 525         p->next = NULL;
 526         p->pack_base = NULL;
 527         p->pack_last_used = 0;
 528         p->pack_use_cnt = 0;
 529         p->pack_local = local;
 530         if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
 531                 memcpy(p->sha1, sha1, 20);
 532         return p;
 533 }
 534
 535 struct packed_git *parse_pack_index(unsigned char *sha1)
 536 {
 537         char *path = sha1_pack_index_name(sha1);
 538         return parse_pack_index_file(sha1, path);
 539 }
 540
 541 struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
 542 {
 543         struct packed_git *p;
 544         unsigned long idx_size;
 545         void *idx_map;
 546         char *path;
 547
 548         if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
 549                 return NULL;
 550
 551         path = sha1_pack_name(sha1);
 552
 553         p = xmalloc(sizeof(*p) + strlen(path) + 2);
 554         strcpy(p->pack_name, path);
 555         p->index_size = idx_size;
 556         p->pack_size = 0;
 557         p->index_base = idx_map;
 558         p->next = NULL;
 559         p->pack_base = NULL;
 560         p->pack_last_used = 0;
 561         p->pack_use_cnt = 0;
 562         memcpy(p->sha1, sha1, 20);
 563         return p;
 564 }
 565
 566 void install_packed_git(struct packed_git *pack)
 567 {
 568         pack->next = packed_git;
 569         packed_git = pack;
 570 }
 571
 572 static void prepare_packed_git_one(char *objdir, int local)
 573 {
 574         char path[PATH_MAX];
 575         int len;
 576         DIR *dir;
 577         struct dirent *de;
 578
 579         sprintf(path, "%s/pack", objdir);
 580         len = strlen(path);
 581         dir = opendir(path);
 582         if (!dir) {
 583                 if (errno != ENOENT)
 584                         error("unable to open object pack directory: %s: %s",
 585                               path, strerror(errno));
 586                 return;
 587         }
 588         path[len++] = '/';
 589         while ((de = readdir(dir)) != NULL) {
 590                 int namelen = strlen(de->d_name);
 591                 struct packed_git *p;
 592
 593                 if (!has_extension(de->d_name, ".idx"))
 594                         continue;
 595
 596                 /* we have .idx.  Is it a file we can map? */
 597                 strcpy(path + len, de->d_name);
 598                 for (p = packed_git; p; p = p->next) {
 599                         if (!memcmp(path, p->pack_name, len + namelen - 4))
 600                                 break;
 601                 }
 602                 if (p)
 603                         continue;
 604                 p = add_packed_git(path, len + namelen, local);
 605                 if (!p)
 606                         continue;
 607                 p->next = packed_git;
 608                 packed_git = p;
 609         }
 610         closedir(dir);
 611 }
 612
 613 static int prepare_packed_git_run_once = 0;
 614 void prepare_packed_git(void)
 615 {
 616         struct alternate_object_database *alt;
 617
 618         if (prepare_packed_git_run_once)
 619                 return;
 620         prepare_packed_git_one(get_object_directory(), 1);
 621         prepare_alt_odb();
 622         for (alt = alt_odb_list; alt; alt = alt->next) {
 623                 alt->name[-1] = 0;
 624                 prepare_packed_git_one(alt->base, 0);
 625                 alt->name[-1] = '/';
 626         }
 627         prepare_packed_git_run_once = 1;
 628 }
 629
 630 static void reprepare_packed_git(void)
 631 {
 632         prepare_packed_git_run_once = 0;
 633         prepare_packed_git();
 634 }
 635
 636 int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
 637 {
 638         char header[100];
 639         unsigned char real_sha1[20];
 640         SHA_CTX c;
 641
 642         SHA1_Init(&c);
 643         SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
 644         SHA1_Update(&c, map, size);
 645         SHA1_Final(real_sha1, &c);
 646         return memcmp(sha1, real_sha1, 20) ? -1 : 0;
 647 }
 648
 649 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 650 {
 651         struct stat st;
 652         void *map;
 653         int fd;
 654         char *filename = find_sha1_file(sha1, &st);
 655
 656         if (!filename) {
 657                 return NULL;
 658         }
 659
 660         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 661         if (fd < 0) {
 662                 /* See if it works without O_NOATIME */
 663                 switch (sha1_file_open_flag) {
 664                 default:
 665                         fd = open(filename, O_RDONLY);
 666                         if (fd >= 0)
 667                                 break;
 668                 /* Fallthrough */
 669                 case 0:
 670                         return NULL;
 671                 }
 672
 673                 /* If it failed once, it will probably fail again.
 674                  * Stop using O_NOATIME
 675                  */
 676                 sha1_file_open_flag = 0;
 677         }
 678         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 679         close(fd);
 680         if (map == MAP_FAILED)
 681                 return NULL;
 682         *size = st.st_size;
 683         return map;
 684 }
 685
 686 int legacy_loose_object(unsigned char *map)
 687 {
 688         unsigned int word;
 689
 690         /*
 691          * Is it a zlib-compressed buffer? If so, the first byte
 692          * must be 0x78 (15-bit window size, deflated), and the
 693          * first 16-bit word is evenly divisible by 31
 694          */
 695         word = (map[0] << 8) + map[1];
 696         if (map[0] == 0x78 && !(word % 31))
 697                 return 1;
 698         else
 699                 return 0;
 700 }
 701
 702 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 703 {
 704         unsigned char c;
 705         unsigned int bits;
 706         unsigned long size;
 707         static const char *typename[8] = {
 708                 NULL,   /* OBJ_EXT */
 709                 "commit", "tree", "blob", "tag",
 710                 NULL, NULL, NULL
 711         };
 712         const char *type;
 713
 714         /* Get the data stream */
 715         memset(stream, 0, sizeof(*stream));
 716         stream->next_in = map;
 717         stream->avail_in = mapsize;
 718         stream->next_out = buffer;
 719         stream->avail_out = bufsiz;
 720
 721         if (legacy_loose_object(map)) {
 722                 inflateInit(stream);
 723                 return inflate(stream, 0);
 724         }
 725
 726         c = *map++;
 727         mapsize--;
 728         type = typename[(c >> 4) & 7];
 729         if (!type)
 730                 return -1;
 731
 732         bits = 4;
 733         size = c & 0xf;
 734         while ((c & 0x80)) {
 735                 if (bits >= 8*sizeof(long))
 736                         return -1;
 737                 c = *map++;
 738                 size += (c & 0x7f) << bits;
 739                 bits += 7;
 740                 mapsize--;
 741         }
 742
 743         /* Set up the stream for the rest.. */
 744         stream->next_in = map;
 745         stream->avail_in = mapsize;
 746         inflateInit(stream);
 747
 748         /* And generate the fake traditional header */
 749         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", type, size);
 750         return 0;
 751 }
 752
 753 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 754 {
 755         int bytes = strlen(buffer) + 1;
 756         unsigned char *buf = xmalloc(1+size);
 757         unsigned long n;
 758
 759         n = stream->total_out - bytes;
 760         if (n > size)
 761                 n = size;
 762         memcpy(buf, (char *) buffer + bytes, n);
 763         bytes = n;
 764         if (bytes < size) {
 765                 stream->next_out = buf + bytes;
 766                 stream->avail_out = size - bytes;
 767                 while (inflate(stream, Z_FINISH) == Z_OK)
 768                         /* nothing */;
 769         }
 770         buf[size] = 0;
 771         inflateEnd(stream);
 772         return buf;
 773 }
 774
 775 /*
 776  * We used to just use "sscanf()", but that's actually way
 777  * too permissive for what we want to check. So do an anal
 778  * object header parse by hand.
 779  */
 780 static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 781 {
 782         int i;
 783         unsigned long size;
 784
 785         /*
 786          * The type can be at most ten bytes (including the
 787          * terminating '\0' that we add), and is followed by
 788          * a space.
 789          */
 790         i = 10;
 791         for (;;) {
 792                 char c = *hdr++;
 793                 if (c == ' ')
 794                         break;
 795                 if (!--i)
 796                         return -1;
 797                 *type++ = c;
 798         }
 799         *type = 0;
 800
 801         /*
 802          * The length must follow immediately, and be in canonical
 803          * decimal format (ie "010" is not valid).
 804          */
 805         size = *hdr++ - '0';
 806         if (size > 9)
 807                 return -1;
 808         if (size) {
 809                 for (;;) {
 810                         unsigned long c = *hdr - '0';
 811                         if (c > 9)
 812                                 break;
 813                         hdr++;
 814                         size = size * 10 + c;
 815                 }
 816         }
 817         *sizep = size;
 818
 819         /*
 820          * The length must be followed by a zero byte
 821          */
 822         return *hdr ? -1 : 0;
 823 }
 824
 825 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 826 {
 827         int ret;
 828         z_stream stream;
 829         char hdr[8192];
 830
 831         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 832         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 833                 return NULL;
 834
 835         return unpack_sha1_rest(&stream, hdr, *size);
 836 }
 837
 838 /* forward declaration for a mutually recursive function */
 839 static int packed_object_info(struct pack_entry *entry,
 840                               char *type, unsigned long *sizep);
 841
 842 static int packed_delta_info(unsigned char *base_sha1,
 843                              unsigned long delta_size,
 844                              unsigned long left,
 845                              char *type,
 846                              unsigned long *sizep,
 847                              struct packed_git *p)
 848 {
 849         struct pack_entry base_ent;
 850
 851         if (left < 20)
 852                 die("truncated pack file");
 853
 854         /* The base entry _must_ be in the same pack */
 855         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 856                 die("failed to find delta-pack base object %s",
 857                     sha1_to_hex(base_sha1));
 858
 859         /* We choose to only get the type of the base object and
 860          * ignore potentially corrupt pack file that expects the delta
 861          * based on a base with a wrong size.  This saves tons of
 862          * inflate() calls.
 863          */
 864
 865         if (packed_object_info(&base_ent, type, NULL))
 866                 die("cannot get info for delta-pack base");
 867
 868         if (sizep) {
 869                 const unsigned char *data;
 870                 unsigned char delta_head[64];
 871                 unsigned long result_size;
 872                 z_stream stream;
 873                 int st;
 874
 875                 memset(&stream, 0, sizeof(stream));
 876
 877                 data = stream.next_in = base_sha1 + 20;
 878                 stream.avail_in = left - 20;
 879                 stream.next_out = delta_head;
 880                 stream.avail_out = sizeof(delta_head);
 881
 882                 inflateInit(&stream);
 883                 st = inflate(&stream, Z_FINISH);
 884                 inflateEnd(&stream);
 885                 if ((st != Z_STREAM_END) &&
 886                     stream.total_out != sizeof(delta_head))
 887                         die("delta data unpack-initial failed");
 888
 889                 /* Examine the initial part of the delta to figure out
 890                  * the result size.
 891                  */
 892                 data = delta_head;
 893
 894                 /* ignore base size */
 895                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 896
 897                 /* Read the result size */
 898                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 899                 *sizep = result_size;
 900         }
 901         return 0;
 902 }
 903
 904 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 905         enum object_type *type, unsigned long *sizep)
 906 {
 907         unsigned shift;
 908         unsigned char *pack, c;
 909         unsigned long size;
 910
 911         if (offset >= p->pack_size)
 912                 die("object offset outside of pack file");
 913
 914         pack =  (unsigned char *) p->pack_base + offset;
 915         c = *pack++;
 916         offset++;
 917         *type = (c >> 4) & 7;
 918         size = c & 15;
 919         shift = 4;
 920         while (c & 0x80) {
 921                 if (offset >= p->pack_size)
 922                         die("object offset outside of pack file");
 923                 c = *pack++;
 924                 offset++;
 925                 size += (c & 0x7f) << shift;
 926                 shift += 7;
 927         }
 928         *sizep = size;
 929         return offset;
 930 }
 931
 932 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 933                            unsigned char *base, unsigned long *sizep,
 934                            enum object_type *kindp)
 935 {
 936         unsigned long ptr;
 937         int status = -1;
 938
 939         use_packed_git(p);
 940         ptr = offset;
 941         ptr = unpack_object_header(p, ptr, kindp, sizep);
 942         if (*kindp != OBJ_DELTA)
 943                 goto done;
 944         memcpy(base, (char *) p->pack_base + ptr, 20);
 945         status = 0;
 946  done:
 947         unuse_packed_git(p);
 948         return status;
 949 }
 950
 951 void packed_object_info_detail(struct pack_entry *e,
 952                                char *type,
 953                                unsigned long *size,
 954                                unsigned long *store_size,
 955                                unsigned int *delta_chain_length,
 956                                unsigned char *base_sha1)
 957 {
 958         struct packed_git *p = e->p;
 959         unsigned long offset;
 960         unsigned char *pack;
 961         enum object_type kind;
 962
 963         offset = unpack_object_header(p, e->offset, &kind, size);
 964         pack = (unsigned char *) p->pack_base + offset;
 965         if (kind != OBJ_DELTA)
 966                 *delta_chain_length = 0;
 967         else {
 968                 unsigned int chain_length = 0;
 969                 if (p->pack_size <= offset + 20)
 970                         die("pack file %s records an incomplete delta base",
 971                             p->pack_name);
 972                 memcpy(base_sha1, pack, 20);
 973                 do {
 974                         struct pack_entry base_ent;
 975                         unsigned long junk;
 976
 977                         find_pack_entry_one(pack, &base_ent, p);
 978                         offset = unpack_object_header(p, base_ent.offset,
 979                                                       &kind, &junk);
 980                         pack = (unsigned char *) p->pack_base + offset;
 981                         chain_length++;
 982                 } while (kind == OBJ_DELTA);
 983                 *delta_chain_length = chain_length;
 984         }
 985         switch (kind) {
 986         case OBJ_COMMIT:
 987                 strcpy(type, commit_type);
 988                 break;
 989         case OBJ_TREE:
 990                 strcpy(type, tree_type);
 991                 break;
 992         case OBJ_BLOB:
 993                 strcpy(type, blob_type);
 994                 break;
 995         case OBJ_TAG:
 996                 strcpy(type, tag_type);
 997                 break;
 998         default:
 999                 die("corrupted pack file %s containing object of kind %d",
1000                     p->pack_name, kind);
1001         }
1002         *store_size = 0; /* notyet */
1003 }
1004
1005 static int packed_object_info(struct pack_entry *entry,
1006                               char *type, unsigned long *sizep)
1007 {
1008         struct packed_git *p = entry->p;
1009         unsigned long offset, size, left;
1010         unsigned char *pack;
1011         enum object_type kind;
1012         int retval;
1013
1014         if (use_packed_git(p))
1015                 die("cannot map packed file");
1016
1017         offset = unpack_object_header(p, entry->offset, &kind, &size);
1018         pack = (unsigned char *) p->pack_base + offset;
1019         left = p->pack_size - offset;
1020
1021         switch (kind) {
1022         case OBJ_DELTA:
1023                 retval = packed_delta_info(pack, size, left, type, sizep, p);
1024                 unuse_packed_git(p);
1025                 return retval;
1026         case OBJ_COMMIT:
1027                 strcpy(type, commit_type);
1028                 break;
1029         case OBJ_TREE:
1030                 strcpy(type, tree_type);
1031                 break;
1032         case OBJ_BLOB:
1033                 strcpy(type, blob_type);
1034                 break;
1035         case OBJ_TAG:
1036                 strcpy(type, tag_type);
1037                 break;
1038         default:
1039                 die("corrupted pack file %s containing object of kind %d",
1040                     p->pack_name, kind);
1041         }
1042         if (sizep)
1043                 *sizep = size;
1044         unuse_packed_git(p);
1045         return 0;
1046 }
1047
1048 /* forward declaration for a mutually recursive function */
1049 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
1050
1051 static void *unpack_delta_entry(unsigned char *base_sha1,
1052                                 unsigned long delta_size,
1053                                 unsigned long left,
1054                                 char *type,
1055                                 unsigned long *sizep,
1056                                 struct packed_git *p)
1057 {
1058         struct pack_entry base_ent;
1059         void *data, *delta_data, *result, *base;
1060         unsigned long data_size, result_size, base_size;
1061         z_stream stream;
1062         int st;
1063
1064         if (left < 20)
1065                 die("truncated pack file");
1066
1067         /* The base entry _must_ be in the same pack */
1068         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1069                 die("failed to find delta-pack base object %s",
1070                     sha1_to_hex(base_sha1));
1071         base = unpack_entry_gently(&base_ent, type, &base_size);
1072         if (!base)
1073                 die("failed to read delta-pack base object %s",
1074                     sha1_to_hex(base_sha1));
1075
1076         data = base_sha1 + 20;
1077         data_size = left - 20;
1078         delta_data = xmalloc(delta_size);
1079
1080         memset(&stream, 0, sizeof(stream));
1081
1082         stream.next_in = data;
1083         stream.avail_in = data_size;
1084         stream.next_out = delta_data;
1085         stream.avail_out = delta_size;
1086
1087         inflateInit(&stream);
1088         st = inflate(&stream, Z_FINISH);
1089         inflateEnd(&stream);
1090         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1091                 die("delta data unpack failed");
1092
1093         result = patch_delta(base, base_size,
1094                              delta_data, delta_size,
1095                              &result_size);
1096         if (!result)
1097                 die("failed to apply delta");
1098         free(delta_data);
1099         free(base);
1100         *sizep = result_size;
1101         return result;
1102 }
1103
1104 static void *unpack_non_delta_entry(unsigned char *data,
1105                                     unsigned long size,
1106                                     unsigned long left)
1107 {
1108         int st;
1109         z_stream stream;
1110         unsigned char *buffer;
1111
1112         buffer = xmalloc(size + 1);
1113         buffer[size] = 0;
1114         memset(&stream, 0, sizeof(stream));
1115         stream.next_in = data;
1116         stream.avail_in = left;
1117         stream.next_out = buffer;
1118         stream.avail_out = size;
1119
1120         inflateInit(&stream);
1121         st = inflate(&stream, Z_FINISH);
1122         inflateEnd(&stream);
1123         if ((st != Z_STREAM_END) || stream.total_out != size) {
1124                 free(buffer);
1125                 return NULL;
1126         }
1127
1128         return buffer;
1129 }
1130
1131 static void *unpack_entry(struct pack_entry *entry,
1132                           char *type, unsigned long *sizep)
1133 {
1134         struct packed_git *p = entry->p;
1135         void *retval;
1136
1137         if (use_packed_git(p))
1138                 die("cannot map packed file");
1139         retval = unpack_entry_gently(entry, type, sizep);
1140         unuse_packed_git(p);
1141         if (!retval)
1142                 die("corrupted pack file %s", p->pack_name);
1143         return retval;
1144 }
1145
1146 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1147 void *unpack_entry_gently(struct pack_entry *entry,
1148                           char *type, unsigned long *sizep)
1149 {
1150         struct packed_git *p = entry->p;
1151         unsigned long offset, size, left;
1152         unsigned char *pack;
1153         enum object_type kind;
1154         void *retval;
1155
1156         offset = unpack_object_header(p, entry->offset, &kind, &size);
1157         pack = (unsigned char *) p->pack_base + offset;
1158         left = p->pack_size - offset;
1159         switch (kind) {
1160         case OBJ_DELTA:
1161                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1162                 return retval;
1163         case OBJ_COMMIT:
1164                 strcpy(type, commit_type);
1165                 break;
1166         case OBJ_TREE:
1167                 strcpy(type, tree_type);
1168                 break;
1169         case OBJ_BLOB:
1170                 strcpy(type, blob_type);
1171                 break;
1172         case OBJ_TAG:
1173                 strcpy(type, tag_type);
1174                 break;
1175         default:
1176                 return NULL;
1177         }
1178         *sizep = size;
1179         retval = unpack_non_delta_entry(pack, size, left);
1180         return retval;
1181 }
1182
1183 int num_packed_objects(const struct packed_git *p)
1184 {
1185         /* See check_packed_git_idx() */
1186         return (p->index_size - 20 - 20 - 4*256) / 24;
1187 }
1188
1189 int nth_packed_object_sha1(const struct packed_git *p, int n,
1190                            unsigned char* sha1)
1191 {
1192         void *index = p->index_base + 256;
1193         if (n < 0 || num_packed_objects(p) <= n)
1194                 return -1;
1195         memcpy(sha1, (char *) index + (24 * n) + 4, 20);
1196         return 0;
1197 }
1198
1199 int find_pack_entry_one(const unsigned char *sha1,
1200                         struct pack_entry *e, struct packed_git *p)
1201 {
1202         unsigned int *level1_ofs = p->index_base;
1203         int hi = ntohl(level1_ofs[*sha1]);
1204         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1205         void *index = p->index_base + 256;
1206
1207         do {
1208                 int mi = (lo + hi) / 2;
1209                 int cmp = memcmp((char *) index + (24 * mi) + 4, sha1, 20);
1210                 if (!cmp) {
1211                         e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1212                         memcpy(e->sha1, sha1, 20);
1213                         e->p = p;
1214                         return 1;
1215                 }
1216                 if (cmp > 0)
1217                         hi = mi;
1218                 else
1219                         lo = mi+1;
1220         } while (lo < hi);
1221         return 0;
1222 }
1223
1224 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1225 {
1226         struct packed_git *p;
1227         prepare_packed_git();
1228
1229         for (p = packed_git; p; p = p->next) {
1230                 if (find_pack_entry_one(sha1, e, p))
1231                         return 1;
1232         }
1233         return 0;
1234 }
1235
1236 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1237                                   struct packed_git *packs)
1238 {
1239         struct packed_git *p;
1240         struct pack_entry e;
1241
1242         for (p = packs; p; p = p->next) {
1243                 if (find_pack_entry_one(sha1, &e, p))
1244                         return p;
1245         }
1246         return NULL;
1247
1248 }
1249
1250 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1251 {
1252         int status;
1253         unsigned long mapsize, size;
1254         void *map;
1255         z_stream stream;
1256         char hdr[128];
1257
1258         map = map_sha1_file(sha1, &mapsize);
1259         if (!map) {
1260                 struct pack_entry e;
1261
1262                 if (find_pack_entry(sha1, &e))
1263                         return packed_object_info(&e, type, sizep);
1264                 reprepare_packed_git();
1265                 if (find_pack_entry(sha1, &e))
1266                         return packed_object_info(&e, type, sizep);
1267                 return error("unable to find %s", sha1_to_hex(sha1));
1268         }
1269         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1270                 status = error("unable to unpack %s header",
1271                                sha1_to_hex(sha1));
1272         if (parse_sha1_header(hdr, type, &size) < 0)
1273                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1274         else {
1275                 status = 0;
1276                 if (sizep)
1277                         *sizep = size;
1278         }
1279         inflateEnd(&stream);
1280         munmap(map, mapsize);
1281         return status;
1282 }
1283
1284 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1285 {
1286         struct pack_entry e;
1287
1288         if (!find_pack_entry(sha1, &e)) {
1289                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1290                 return NULL;
1291         }
1292         return unpack_entry(&e, type, size);
1293 }
1294
1295 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1296 {
1297         unsigned long mapsize;
1298         void *map, *buf;
1299         struct pack_entry e;
1300
1301         if (find_pack_entry(sha1, &e))
1302                 return read_packed_sha1(sha1, type, size);
1303         map = map_sha1_file(sha1, &mapsize);
1304         if (map) {
1305                 buf = unpack_sha1_file(map, mapsize, type, size);
1306                 munmap(map, mapsize);
1307                 return buf;
1308         }
1309         reprepare_packed_git();
1310         if (find_pack_entry(sha1, &e))
1311                 return read_packed_sha1(sha1, type, size);
1312         return NULL;
1313 }
1314
1315 void *read_object_with_reference(const unsigned char *sha1,
1316                                  const char *required_type,
1317                                  unsigned long *size,
1318                                  unsigned char *actual_sha1_return)
1319 {
1320         char type[20];
1321         void *buffer;
1322         unsigned long isize;
1323         unsigned char actual_sha1[20];
1324
1325         memcpy(actual_sha1, sha1, 20);
1326         while (1) {
1327                 int ref_length = -1;
1328                 const char *ref_type = NULL;
1329
1330                 buffer = read_sha1_file(actual_sha1, type, &isize);
1331                 if (!buffer)
1332                         return NULL;
1333                 if (!strcmp(type, required_type)) {
1334                         *size = isize;
1335                         if (actual_sha1_return)
1336                                 memcpy(actual_sha1_return, actual_sha1, 20);
1337                         return buffer;
1338                 }
1339                 /* Handle references */
1340                 else if (!strcmp(type, commit_type))
1341                         ref_type = "tree ";
1342                 else if (!strcmp(type, tag_type))
1343                         ref_type = "object ";
1344                 else {
1345                         free(buffer);
1346                         return NULL;
1347                 }
1348                 ref_length = strlen(ref_type);
1349
1350                 if (memcmp(buffer, ref_type, ref_length) ||
1351                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1352                         free(buffer);
1353                         return NULL;
1354                 }
1355                 free(buffer);
1356                 /* Now we have the ID of the referred-to object in
1357                  * actual_sha1.  Check again. */
1358         }
1359 }
1360
1361 char *write_sha1_file_prepare(void *buf,
1362                               unsigned long len,
1363                               const char *type,
1364                               unsigned char *sha1,
1365                               unsigned char *hdr,
1366                               int *hdrlen)
1367 {
1368         SHA_CTX c;
1369
1370         /* Generate the header */
1371         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1372
1373         /* Sha1.. */
1374         SHA1_Init(&c);
1375         SHA1_Update(&c, hdr, *hdrlen);
1376         SHA1_Update(&c, buf, len);
1377         SHA1_Final(sha1, &c);
1378
1379         return sha1_file_name(sha1);
1380 }
1381
1382 /*
1383  * Link the tempfile to the final place, possibly creating the
1384  * last directory level as you do so.
1385  *
1386  * Returns the errno on failure, 0 on success.
1387  */
1388 static int link_temp_to_file(const char *tmpfile, char *filename)
1389 {
1390         int ret;
1391         char *dir;
1392
1393         if (!link(tmpfile, filename))
1394                 return 0;
1395
1396         /*
1397          * Try to mkdir the last path component if that failed.
1398          *
1399          * Re-try the "link()" regardless of whether the mkdir
1400          * succeeds, since a race might mean that somebody
1401          * else succeeded.
1402          */
1403         ret = errno;
1404         dir = strrchr(filename, '/');
1405         if (dir) {
1406                 *dir = 0;
1407                 mkdir(filename, 0777);
1408                 if (adjust_shared_perm(filename))
1409                         return -2;
1410                 *dir = '/';
1411                 if (!link(tmpfile, filename))
1412                         return 0;
1413                 ret = errno;
1414         }
1415         return ret;
1416 }
1417
1418 /*
1419  * Move the just written object into its final resting place
1420  */
1421 int move_temp_to_file(const char *tmpfile, char *filename)
1422 {
1423         int ret = link_temp_to_file(tmpfile, filename);
1424
1425         /*
1426          * Coda hack - coda doesn't like cross-directory links,
1427          * so we fall back to a rename, which will mean that it
1428          * won't be able to check collisions, but that's not a
1429          * big deal.
1430          *
1431          * The same holds for FAT formatted media.
1432          *
1433          * When this succeeds, we just return 0. We have nothing
1434          * left to unlink.
1435          */
1436         if (ret && ret != EEXIST) {
1437                 if (!rename(tmpfile, filename))
1438                         return 0;
1439                 ret = errno;
1440         }
1441         unlink(tmpfile);
1442         if (ret) {
1443                 if (ret != EEXIST) {
1444                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1445                         return -1;
1446                 }
1447                 /* FIXME!!! Collision check here ? */
1448         }
1449
1450         return 0;
1451 }
1452
1453 static int write_buffer(int fd, const void *buf, size_t len)
1454 {
1455         while (len) {
1456                 ssize_t size;
1457
1458                 size = write(fd, buf, len);
1459                 if (!size)
1460                         return error("file write: disk full");
1461                 if (size < 0) {
1462                         if (errno == EINTR || errno == EAGAIN)
1463                                 continue;
1464                         return error("file write error (%s)", strerror(errno));
1465                 }
1466                 len -= size;
1467                 buf = (char *) buf + size;
1468         }
1469         return 0;
1470 }
1471
1472 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1473 {
1474         int hdr_len;
1475         unsigned char c;
1476
1477         c = (type << 4) | (len & 15);
1478         len >>= 4;
1479         hdr_len = 1;
1480         while (len) {
1481                 *hdr++ = c | 0x80;
1482                 hdr_len++;
1483                 c = (len & 0x7f);
1484                 len >>= 7;
1485         }
1486         *hdr = c;
1487         return hdr_len;
1488 }
1489
1490 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1491 {
1492         int obj_type, hdr;
1493
1494         if (use_legacy_headers) {
1495                 while (deflate(stream, 0) == Z_OK)
1496                         /* nothing */;
1497                 return;
1498         }
1499         if (!strcmp(type, blob_type))
1500                 obj_type = OBJ_BLOB;
1501         else if (!strcmp(type, tree_type))
1502                 obj_type = OBJ_TREE;
1503         else if (!strcmp(type, commit_type))
1504                 obj_type = OBJ_COMMIT;
1505         else if (!strcmp(type, tag_type))
1506                 obj_type = OBJ_TAG;
1507         else
1508                 die("trying to generate bogus object of type '%s'", type);
1509         hdr = write_binary_header(stream->next_out, obj_type, len);
1510         stream->total_out = hdr;
1511         stream->next_out += hdr;
1512         stream->avail_out -= hdr;
1513 }
1514
1515 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1516 {
1517         int size;
1518         unsigned char *compressed;
1519         z_stream stream;
1520         unsigned char sha1[20];
1521         char *filename;
1522         static char tmpfile[PATH_MAX];
1523         unsigned char hdr[50];
1524         int fd, hdrlen;
1525
1526         /* Normally if we have it in the pack then we do not bother writing
1527          * it out into .git/objects/??/?{38} file.
1528          */
1529         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1530         if (returnsha1)
1531                 memcpy(returnsha1, sha1, 20);
1532         if (has_sha1_file(sha1))
1533                 return 0;
1534         fd = open(filename, O_RDONLY);
1535         if (fd >= 0) {
1536                 /*
1537                  * FIXME!!! We might do collision checking here, but we'd
1538                  * need to uncompress the old file and check it. Later.
1539                  */
1540                 close(fd);
1541                 return 0;
1542         }
1543
1544         if (errno != ENOENT) {
1545                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1546                 return -1;
1547         }
1548
1549         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1550
1551         fd = mkstemp(tmpfile);
1552         if (fd < 0) {
1553                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1554                 return -1;
1555         }
1556
1557         /* Set it up */
1558         memset(&stream, 0, sizeof(stream));
1559         deflateInit(&stream, zlib_compression_level);
1560         size = 8 + deflateBound(&stream, len+hdrlen);
1561         compressed = xmalloc(size);
1562
1563         /* Compress it */
1564         stream.next_out = compressed;
1565         stream.avail_out = size;
1566
1567         /* First header.. */
1568         stream.next_in = hdr;
1569         stream.avail_in = hdrlen;
1570         setup_object_header(&stream, type, len);
1571
1572         /* Then the data itself.. */
1573         stream.next_in = buf;
1574         stream.avail_in = len;
1575         while (deflate(&stream, Z_FINISH) == Z_OK)
1576                 /* nothing */;
1577         deflateEnd(&stream);
1578         size = stream.total_out;
1579
1580         if (write_buffer(fd, compressed, size) < 0)
1581                 die("unable to write sha1 file");
1582         fchmod(fd, 0444);
1583         close(fd);
1584         free(compressed);
1585
1586         return move_temp_to_file(tmpfile, filename);
1587 }
1588
1589 /*
1590  * We need to unpack and recompress the object for writing
1591  * it out to a different file.
1592  */
1593 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1594 {
1595         size_t size;
1596         z_stream stream;
1597         unsigned char *unpacked;
1598         unsigned long len;
1599         char type[20];
1600         char hdr[50];
1601         int hdrlen;
1602         void *buf;
1603
1604         /* need to unpack and recompress it by itself */
1605         unpacked = read_packed_sha1(sha1, type, &len);
1606
1607         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1608
1609         /* Set it up */
1610         memset(&stream, 0, sizeof(stream));
1611         deflateInit(&stream, zlib_compression_level);
1612         size = deflateBound(&stream, len + hdrlen);
1613         buf = xmalloc(size);
1614
1615         /* Compress it */
1616         stream.next_out = buf;
1617         stream.avail_out = size;
1618
1619         /* First header.. */
1620         stream.next_in = (void *)hdr;
1621         stream.avail_in = hdrlen;
1622         while (deflate(&stream, 0) == Z_OK)
1623                 /* nothing */;
1624
1625         /* Then the data itself.. */
1626         stream.next_in = unpacked;
1627         stream.avail_in = len;
1628         while (deflate(&stream, Z_FINISH) == Z_OK)
1629                 /* nothing */;
1630         deflateEnd(&stream);
1631         free(unpacked);
1632
1633         *objsize = stream.total_out;
1634         return buf;
1635 }
1636
1637 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1638 {
1639         int retval;
1640         unsigned long objsize;
1641         void *buf = map_sha1_file(sha1, &objsize);
1642
1643         if (buf) {
1644                 retval = write_buffer(fd, buf, objsize);
1645                 munmap(buf, objsize);
1646                 return retval;
1647         }
1648
1649         buf = repack_object(sha1, &objsize);
1650         retval = write_buffer(fd, buf, objsize);
1651         free(buf);
1652         return retval;
1653 }
1654
1655 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1656                        size_t bufsize, size_t *bufposn)
1657 {
1658         char tmpfile[PATH_MAX];
1659         int local;
1660         z_stream stream;
1661         unsigned char real_sha1[20];
1662         unsigned char discard[4096];
1663         int ret;
1664         SHA_CTX c;
1665
1666         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1667
1668         local = mkstemp(tmpfile);
1669         if (local < 0)
1670                 return error("Couldn't open %s for %s",
1671                              tmpfile, sha1_to_hex(sha1));
1672
1673         memset(&stream, 0, sizeof(stream));
1674
1675         inflateInit(&stream);
1676
1677         SHA1_Init(&c);
1678
1679         do {
1680                 ssize_t size;
1681                 if (*bufposn) {
1682                         stream.avail_in = *bufposn;
1683                         stream.next_in = (unsigned char *) buffer;
1684                         do {
1685                                 stream.next_out = discard;
1686                                 stream.avail_out = sizeof(discard);
1687                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1688                                 SHA1_Update(&c, discard, sizeof(discard) -
1689                                             stream.avail_out);
1690                         } while (stream.avail_in && ret == Z_OK);
1691                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1692                                 die("unable to write sha1 file");
1693                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1694                                 stream.avail_in);
1695                         *bufposn = stream.avail_in;
1696                         if (ret != Z_OK)
1697                                 break;
1698                 }
1699                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1700                 if (size <= 0) {
1701                         close(local);
1702                         unlink(tmpfile);
1703                         if (!size)
1704                                 return error("Connection closed?");
1705                         perror("Reading from connection");
1706                         return -1;
1707                 }
1708                 *bufposn += size;
1709         } while (1);
1710         inflateEnd(&stream);
1711
1712         close(local);
1713         SHA1_Final(real_sha1, &c);
1714         if (ret != Z_STREAM_END) {
1715                 unlink(tmpfile);
1716                 return error("File %s corrupted", sha1_to_hex(sha1));
1717         }
1718         if (memcmp(sha1, real_sha1, 20)) {
1719                 unlink(tmpfile);
1720                 return error("File %s has bad hash", sha1_to_hex(sha1));
1721         }
1722
1723         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1724 }
1725
1726 int has_pack_index(const unsigned char *sha1)
1727 {
1728         struct stat st;
1729         if (stat(sha1_pack_index_name(sha1), &st))
1730                 return 0;
1731         return 1;
1732 }
1733
1734 int has_pack_file(const unsigned char *sha1)
1735 {
1736         struct stat st;
1737         if (stat(sha1_pack_name(sha1), &st))
1738                 return 0;
1739         return 1;
1740 }
1741
1742 int has_sha1_pack(const unsigned char *sha1)
1743 {
1744         struct pack_entry e;
1745         return find_pack_entry(sha1, &e);
1746 }
1747
1748 int has_sha1_file(const unsigned char *sha1)
1749 {
1750         struct stat st;
1751         struct pack_entry e;
1752
1753         if (find_pack_entry(sha1, &e))
1754                 return 1;
1755         return find_sha1_file(sha1, &st) ? 1 : 0;
1756 }
1757
1758 /*
1759  * reads from fd as long as possible into a supplied buffer of size bytes.
1760  * If necessary the buffer's size is increased using realloc()
1761  *
1762  * returns 0 if anything went fine and -1 otherwise
1763  *
1764  * NOTE: both buf and size may change, but even when -1 is returned
1765  * you still have to free() it yourself.
1766  */
1767 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1768 {
1769         char* buf = *return_buf;
1770         unsigned long size = *return_size;
1771         int iret;
1772         unsigned long off = 0;
1773
1774         do {
1775                 iret = xread(fd, buf + off, size - off);
1776                 if (iret > 0) {
1777                         off += iret;
1778                         if (off == size) {
1779                                 size *= 2;
1780                                 buf = realloc(buf, size);
1781                         }
1782                 }
1783         } while (iret > 0);
1784
1785         *return_buf = buf;
1786         *return_size = off;
1787
1788         if (iret < 0)
1789                 return -1;
1790         return 0;
1791 }
1792
1793 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1794 {
1795         unsigned long size = 4096;
1796         char *buf = malloc(size);
1797         int ret;
1798         unsigned char hdr[50];
1799         int hdrlen;
1800
1801         if (read_pipe(fd, &buf, &size)) {
1802                 free(buf);
1803                 return -1;
1804         }
1805
1806         if (!type)
1807                 type = blob_type;
1808         if (write_object)
1809                 ret = write_sha1_file(buf, size, type, sha1);
1810         else {
1811                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1812                 ret = 0;
1813         }
1814         free(buf);
1815         return ret;
1816 }
1817
1818 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1819 {
1820         unsigned long size = st->st_size;
1821         void *buf;
1822         int ret;
1823         unsigned char hdr[50];
1824         int hdrlen;
1825
1826         buf = "";
1827         if (size)
1828                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1829         close(fd);
1830         if (buf == MAP_FAILED)
1831                 return -1;
1832
1833         if (!type)
1834                 type = blob_type;
1835         if (write_object)
1836                 ret = write_sha1_file(buf, size, type, sha1);
1837         else {
1838                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1839                 ret = 0;
1840         }
1841         if (size)
1842                 munmap(buf, size);
1843         return ret;
1844 }
1845
1846 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1847 {
1848         int fd;
1849         char *target;
1850
1851         switch (st->st_mode & S_IFMT) {
1852         case S_IFREG:
1853                 fd = open(path, O_RDONLY);
1854                 if (fd < 0)
1855                         return error("open(\"%s\"): %s", path,
1856                                      strerror(errno));
1857                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1858                         return error("%s: failed to insert into database",
1859                                      path);
1860                 break;
1861         case S_IFLNK:
1862                 target = xmalloc(st->st_size+1);
1863                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1864                         char *errstr = strerror(errno);
1865                         free(target);
1866                         return error("readlink(\"%s\"): %s", path,
1867                                      errstr);
1868                 }
1869                 if (!write_object) {
1870                         unsigned char hdr[50];
1871                         int hdrlen;
1872                         write_sha1_file_prepare(target, st->st_size, blob_type,
1873                                                 sha1, hdr, &hdrlen);
1874                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1875                         return error("%s: failed to insert into database",
1876                                      path);
1877                 free(target);
1878                 break;
1879         default:
1880                 return error("%s: unsupported file type", path);
1881         }
1882         return 0;
1883 }