git.oblomov.eu Git - git/blob - 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 (strcmp(de->d_name + namelen - 4, ".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 static void *map_sha1_file_internal(const unsigned char *sha1,
 650                                     unsigned long *size)
 651 {
 652         struct stat st;
 653         void *map;
 654         int fd;
 655         char *filename = find_sha1_file(sha1, &st);
 656
 657         if (!filename) {
 658                 return NULL;
 659         }
 660
 661         fd = open(filename, O_RDONLY | sha1_file_open_flag);
 662         if (fd < 0) {
 663                 /* See if it works without O_NOATIME */
 664                 switch (sha1_file_open_flag) {
 665                 default:
 666                         fd = open(filename, O_RDONLY);
 667                         if (fd >= 0)
 668                                 break;
 669                 /* Fallthrough */
 670                 case 0:
 671                         return NULL;
 672                 }
 673
 674                 /* If it failed once, it will probably fail again.
 675                  * Stop using O_NOATIME
 676                  */
 677                 sha1_file_open_flag = 0;
 678         }
 679         map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
 680         close(fd);
 681         if (map == MAP_FAILED)
 682                 return NULL;
 683         *size = st.st_size;
 684         return map;
 685 }
 686
 687 static int unpack_sha1_header(z_stream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
 688 {
 689         unsigned char c;
 690         unsigned int word, bits;
 691         unsigned long size;
 692         static const char *typename[8] = {
 693                 NULL,   /* OBJ_EXT */
 694                 "commit", "tree", "blob", "tag",
 695                 NULL, NULL, NULL
 696         };
 697         const char *type;
 698
 699         /* Get the data stream */
 700         memset(stream, 0, sizeof(*stream));
 701         stream->next_in = map;
 702         stream->avail_in = mapsize;
 703         stream->next_out = buffer;
 704         stream->avail_out = bufsiz;
 705
 706         /*
 707          * Is it a zlib-compressed buffer? If so, the first byte
 708          * must be 0x78 (15-bit window size, deflated), and the
 709          * first 16-bit word is evenly divisible by 31
 710          */
 711         word = (map[0] << 8) + map[1];
 712         if (map[0] == 0x78 && !(word % 31)) {
 713                 inflateInit(stream);
 714                 return inflate(stream, 0);
 715         }
 716
 717         c = *map++;
 718         mapsize--;
 719         type = typename[(c >> 4) & 7];
 720         if (!type)
 721                 return -1;
 722
 723         bits = 4;
 724         size = c & 0xf;
 725         while ((c & 0x80)) {
 726                 if (bits >= 8*sizeof(long))
 727                         return -1;
 728                 c = *map++;
 729                 size += (c & 0x7f) << bits;
 730                 bits += 7;
 731                 mapsize--;
 732         }
 733
 734         /* Set up the stream for the rest.. */
 735         stream->next_in = map;
 736         stream->avail_in = mapsize;
 737         inflateInit(stream);
 738
 739         /* And generate the fake traditional header */
 740         stream->total_out = 1 + snprintf(buffer, bufsiz, "%s %lu", type, size);
 741         return 0;
 742 }
 743
 744 static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
 745 {
 746         int bytes = strlen(buffer) + 1;
 747         unsigned char *buf = xmalloc(1+size);
 748         unsigned long n;
 749
 750         n = stream->total_out - bytes;
 751         if (n > size)
 752                 n = size;
 753         memcpy(buf, (char *) buffer + bytes, n);
 754         bytes = n;
 755         if (bytes < size) {
 756                 stream->next_out = buf + bytes;
 757                 stream->avail_out = size - bytes;
 758                 while (inflate(stream, Z_FINISH) == Z_OK)
 759                         /* nothing */;
 760         }
 761         buf[size] = 0;
 762         inflateEnd(stream);
 763         return buf;
 764 }
 765
 766 /*
 767  * We used to just use "sscanf()", but that's actually way
 768  * too permissive for what we want to check. So do an anal
 769  * object header parse by hand.
 770  */
 771 static int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
 772 {
 773         int i;
 774         unsigned long size;
 775
 776         /*
 777          * The type can be at most ten bytes (including the
 778          * terminating '\0' that we add), and is followed by
 779          * a space.
 780          */
 781         i = 10;
 782         for (;;) {
 783                 char c = *hdr++;
 784                 if (c == ' ')
 785                         break;
 786                 if (!--i)
 787                         return -1;
 788                 *type++ = c;
 789         }
 790         *type = 0;
 791
 792         /*
 793          * The length must follow immediately, and be in canonical
 794          * decimal format (ie "010" is not valid).
 795          */
 796         size = *hdr++ - '0';
 797         if (size > 9)
 798                 return -1;
 799         if (size) {
 800                 for (;;) {
 801                         unsigned long c = *hdr - '0';
 802                         if (c > 9)
 803                                 break;
 804                         hdr++;
 805                         size = size * 10 + c;
 806                 }
 807         }
 808         *sizep = size;
 809
 810         /*
 811          * The length must be followed by a zero byte
 812          */
 813         return *hdr ? -1 : 0;
 814 }
 815
 816 void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
 817 {
 818         int ret;
 819         z_stream stream;
 820         char hdr[8192];
 821
 822         ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
 823         if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
 824                 return NULL;
 825
 826         return unpack_sha1_rest(&stream, hdr, *size);
 827 }
 828
 829 /* forward declaration for a mutually recursive function */
 830 static int packed_object_info(struct pack_entry *entry,
 831                               char *type, unsigned long *sizep);
 832
 833 static int packed_delta_info(unsigned char *base_sha1,
 834                              unsigned long delta_size,
 835                              unsigned long left,
 836                              char *type,
 837                              unsigned long *sizep,
 838                              struct packed_git *p)
 839 {
 840         struct pack_entry base_ent;
 841
 842         if (left < 20)
 843                 die("truncated pack file");
 844
 845         /* The base entry _must_ be in the same pack */
 846         if (!find_pack_entry_one(base_sha1, &base_ent, p))
 847                 die("failed to find delta-pack base object %s",
 848                     sha1_to_hex(base_sha1));
 849
 850         /* We choose to only get the type of the base object and
 851          * ignore potentially corrupt pack file that expects the delta
 852          * based on a base with a wrong size.  This saves tons of
 853          * inflate() calls.
 854          */
 855
 856         if (packed_object_info(&base_ent, type, NULL))
 857                 die("cannot get info for delta-pack base");
 858
 859         if (sizep) {
 860                 const unsigned char *data;
 861                 unsigned char delta_head[64];
 862                 unsigned long result_size;
 863                 z_stream stream;
 864                 int st;
 865
 866                 memset(&stream, 0, sizeof(stream));
 867
 868                 data = stream.next_in = base_sha1 + 20;
 869                 stream.avail_in = left - 20;
 870                 stream.next_out = delta_head;
 871                 stream.avail_out = sizeof(delta_head);
 872
 873                 inflateInit(&stream);
 874                 st = inflate(&stream, Z_FINISH);
 875                 inflateEnd(&stream);
 876                 if ((st != Z_STREAM_END) &&
 877                     stream.total_out != sizeof(delta_head))
 878                         die("delta data unpack-initial failed");
 879
 880                 /* Examine the initial part of the delta to figure out
 881                  * the result size.
 882                  */
 883                 data = delta_head;
 884
 885                 /* ignore base size */
 886                 get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 887
 888                 /* Read the result size */
 889                 result_size = get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
 890                 *sizep = result_size;
 891         }
 892         return 0;
 893 }
 894
 895 static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
 896         enum object_type *type, unsigned long *sizep)
 897 {
 898         unsigned shift;
 899         unsigned char *pack, c;
 900         unsigned long size;
 901
 902         if (offset >= p->pack_size)
 903                 die("object offset outside of pack file");
 904
 905         pack =  (unsigned char *) p->pack_base + offset;
 906         c = *pack++;
 907         offset++;
 908         *type = (c >> 4) & 7;
 909         size = c & 15;
 910         shift = 4;
 911         while (c & 0x80) {
 912                 if (offset >= p->pack_size)
 913                         die("object offset outside of pack file");
 914                 c = *pack++;
 915                 offset++;
 916                 size += (c & 0x7f) << shift;
 917                 shift += 7;
 918         }
 919         *sizep = size;
 920         return offset;
 921 }
 922
 923 int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
 924                            unsigned char *base, unsigned long *sizep,
 925                            enum object_type *kindp)
 926 {
 927         unsigned long ptr;
 928         int status = -1;
 929
 930         use_packed_git(p);
 931         ptr = offset;
 932         ptr = unpack_object_header(p, ptr, kindp, sizep);
 933         if (*kindp != OBJ_DELTA)
 934                 goto done;
 935         memcpy(base, (char *) p->pack_base + ptr, 20);
 936         status = 0;
 937  done:
 938         unuse_packed_git(p);
 939         return status;
 940 }
 941
 942 void packed_object_info_detail(struct pack_entry *e,
 943                                char *type,
 944                                unsigned long *size,
 945                                unsigned long *store_size,
 946                                unsigned int *delta_chain_length,
 947                                unsigned char *base_sha1)
 948 {
 949         struct packed_git *p = e->p;
 950         unsigned long offset;
 951         unsigned char *pack;
 952         enum object_type kind;
 953
 954         offset = unpack_object_header(p, e->offset, &kind, size);
 955         pack = (unsigned char *) p->pack_base + offset;
 956         if (kind != OBJ_DELTA)
 957                 *delta_chain_length = 0;
 958         else {
 959                 unsigned int chain_length = 0;
 960                 if (p->pack_size <= offset + 20)
 961                         die("pack file %s records an incomplete delta base",
 962                             p->pack_name);
 963                 memcpy(base_sha1, pack, 20);
 964                 do {
 965                         struct pack_entry base_ent;
 966                         unsigned long junk;
 967
 968                         find_pack_entry_one(pack, &base_ent, p);
 969                         offset = unpack_object_header(p, base_ent.offset,
 970                                                       &kind, &junk);
 971                         pack = (unsigned char *) p->pack_base + offset;
 972                         chain_length++;
 973                 } while (kind == OBJ_DELTA);
 974                 *delta_chain_length = chain_length;
 975         }
 976         switch (kind) {
 977         case OBJ_COMMIT:
 978                 strcpy(type, commit_type);
 979                 break;
 980         case OBJ_TREE:
 981                 strcpy(type, tree_type);
 982                 break;
 983         case OBJ_BLOB:
 984                 strcpy(type, blob_type);
 985                 break;
 986         case OBJ_TAG:
 987                 strcpy(type, tag_type);
 988                 break;
 989         default:
 990                 die("corrupted pack file %s containing object of kind %d",
 991                     p->pack_name, kind);
 992         }
 993         *store_size = 0; /* notyet */
 994 }
 995
 996 static int packed_object_info(struct pack_entry *entry,
 997                               char *type, unsigned long *sizep)
 998 {
 999         struct packed_git *p = entry->p;
1000         unsigned long offset, size, left;
1001         unsigned char *pack;
1002         enum object_type kind;
1003         int retval;
1004
1005         if (use_packed_git(p))
1006                 die("cannot map packed file");
1007
1008         offset = unpack_object_header(p, entry->offset, &kind, &size);
1009         pack = (unsigned char *) p->pack_base + offset;
1010         left = p->pack_size - offset;
1011
1012         switch (kind) {
1013         case OBJ_DELTA:
1014                 retval = packed_delta_info(pack, size, left, type, sizep, p);
1015                 unuse_packed_git(p);
1016                 return retval;
1017         case OBJ_COMMIT:
1018                 strcpy(type, commit_type);
1019                 break;
1020         case OBJ_TREE:
1021                 strcpy(type, tree_type);
1022                 break;
1023         case OBJ_BLOB:
1024                 strcpy(type, blob_type);
1025                 break;
1026         case OBJ_TAG:
1027                 strcpy(type, tag_type);
1028                 break;
1029         default:
1030                 die("corrupted pack file %s containing object of kind %d",
1031                     p->pack_name, kind);
1032         }
1033         if (sizep)
1034                 *sizep = size;
1035         unuse_packed_git(p);
1036         return 0;
1037 }
1038
1039 /* forward declaration for a mutually recursive function */
1040 static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
1041
1042 static void *unpack_delta_entry(unsigned char *base_sha1,
1043                                 unsigned long delta_size,
1044                                 unsigned long left,
1045                                 char *type,
1046                                 unsigned long *sizep,
1047                                 struct packed_git *p)
1048 {
1049         struct pack_entry base_ent;
1050         void *data, *delta_data, *result, *base;
1051         unsigned long data_size, result_size, base_size;
1052         z_stream stream;
1053         int st;
1054
1055         if (left < 20)
1056                 die("truncated pack file");
1057
1058         /* The base entry _must_ be in the same pack */
1059         if (!find_pack_entry_one(base_sha1, &base_ent, p))
1060                 die("failed to find delta-pack base object %s",
1061                     sha1_to_hex(base_sha1));
1062         base = unpack_entry_gently(&base_ent, type, &base_size);
1063         if (!base)
1064                 die("failed to read delta-pack base object %s",
1065                     sha1_to_hex(base_sha1));
1066
1067         data = base_sha1 + 20;
1068         data_size = left - 20;
1069         delta_data = xmalloc(delta_size);
1070
1071         memset(&stream, 0, sizeof(stream));
1072
1073         stream.next_in = data;
1074         stream.avail_in = data_size;
1075         stream.next_out = delta_data;
1076         stream.avail_out = delta_size;
1077
1078         inflateInit(&stream);
1079         st = inflate(&stream, Z_FINISH);
1080         inflateEnd(&stream);
1081         if ((st != Z_STREAM_END) || stream.total_out != delta_size)
1082                 die("delta data unpack failed");
1083
1084         result = patch_delta(base, base_size,
1085                              delta_data, delta_size,
1086                              &result_size);
1087         if (!result)
1088                 die("failed to apply delta");
1089         free(delta_data);
1090         free(base);
1091         *sizep = result_size;
1092         return result;
1093 }
1094
1095 static void *unpack_non_delta_entry(unsigned char *data,
1096                                     unsigned long size,
1097                                     unsigned long left)
1098 {
1099         int st;
1100         z_stream stream;
1101         unsigned char *buffer;
1102
1103         buffer = xmalloc(size + 1);
1104         buffer[size] = 0;
1105         memset(&stream, 0, sizeof(stream));
1106         stream.next_in = data;
1107         stream.avail_in = left;
1108         stream.next_out = buffer;
1109         stream.avail_out = size;
1110
1111         inflateInit(&stream);
1112         st = inflate(&stream, Z_FINISH);
1113         inflateEnd(&stream);
1114         if ((st != Z_STREAM_END) || stream.total_out != size) {
1115                 free(buffer);
1116                 return NULL;
1117         }
1118
1119         return buffer;
1120 }
1121
1122 static void *unpack_entry(struct pack_entry *entry,
1123                           char *type, unsigned long *sizep)
1124 {
1125         struct packed_git *p = entry->p;
1126         void *retval;
1127
1128         if (use_packed_git(p))
1129                 die("cannot map packed file");
1130         retval = unpack_entry_gently(entry, type, sizep);
1131         unuse_packed_git(p);
1132         if (!retval)
1133                 die("corrupted pack file %s", p->pack_name);
1134         return retval;
1135 }
1136
1137 /* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
1138 void *unpack_entry_gently(struct pack_entry *entry,
1139                           char *type, unsigned long *sizep)
1140 {
1141         struct packed_git *p = entry->p;
1142         unsigned long offset, size, left;
1143         unsigned char *pack;
1144         enum object_type kind;
1145         void *retval;
1146
1147         offset = unpack_object_header(p, entry->offset, &kind, &size);
1148         pack = (unsigned char *) p->pack_base + offset;
1149         left = p->pack_size - offset;
1150         switch (kind) {
1151         case OBJ_DELTA:
1152                 retval = unpack_delta_entry(pack, size, left, type, sizep, p);
1153                 return retval;
1154         case OBJ_COMMIT:
1155                 strcpy(type, commit_type);
1156                 break;
1157         case OBJ_TREE:
1158                 strcpy(type, tree_type);
1159                 break;
1160         case OBJ_BLOB:
1161                 strcpy(type, blob_type);
1162                 break;
1163         case OBJ_TAG:
1164                 strcpy(type, tag_type);
1165                 break;
1166         default:
1167                 return NULL;
1168         }
1169         *sizep = size;
1170         retval = unpack_non_delta_entry(pack, size, left);
1171         return retval;
1172 }
1173
1174 int num_packed_objects(const struct packed_git *p)
1175 {
1176         /* See check_packed_git_idx() */
1177         return (p->index_size - 20 - 20 - 4*256) / 24;
1178 }
1179
1180 int nth_packed_object_sha1(const struct packed_git *p, int n,
1181                            unsigned char* sha1)
1182 {
1183         void *index = p->index_base + 256;
1184         if (n < 0 || num_packed_objects(p) <= n)
1185                 return -1;
1186         memcpy(sha1, (char *) index + (24 * n) + 4, 20);
1187         return 0;
1188 }
1189
1190 int find_pack_entry_one(const unsigned char *sha1,
1191                         struct pack_entry *e, struct packed_git *p)
1192 {
1193         unsigned int *level1_ofs = p->index_base;
1194         int hi = ntohl(level1_ofs[*sha1]);
1195         int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1196         void *index = p->index_base + 256;
1197
1198         do {
1199                 int mi = (lo + hi) / 2;
1200                 int cmp = memcmp((char *) index + (24 * mi) + 4, sha1, 20);
1201                 if (!cmp) {
1202                         e->offset = ntohl(*((unsigned int *) ((char *) index + (24 * mi))));
1203                         memcpy(e->sha1, sha1, 20);
1204                         e->p = p;
1205                         return 1;
1206                 }
1207                 if (cmp > 0)
1208                         hi = mi;
1209                 else
1210                         lo = mi+1;
1211         } while (lo < hi);
1212         return 0;
1213 }
1214
1215 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1216 {
1217         struct packed_git *p;
1218         prepare_packed_git();
1219
1220         for (p = packed_git; p; p = p->next) {
1221                 if (find_pack_entry_one(sha1, e, p))
1222                         return 1;
1223         }
1224         return 0;
1225 }
1226
1227 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1228                                   struct packed_git *packs)
1229 {
1230         struct packed_git *p;
1231         struct pack_entry e;
1232
1233         for (p = packs; p; p = p->next) {
1234                 if (find_pack_entry_one(sha1, &e, p))
1235                         return p;
1236         }
1237         return NULL;
1238
1239 }
1240
1241 int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
1242 {
1243         int status;
1244         unsigned long mapsize, size;
1245         void *map;
1246         z_stream stream;
1247         char hdr[128];
1248
1249         map = map_sha1_file_internal(sha1, &mapsize);
1250         if (!map) {
1251                 struct pack_entry e;
1252
1253                 if (find_pack_entry(sha1, &e))
1254                         return packed_object_info(&e, type, sizep);
1255                 reprepare_packed_git();
1256                 if (find_pack_entry(sha1, &e))
1257                         return packed_object_info(&e, type, sizep);
1258                 return error("unable to find %s", sha1_to_hex(sha1));
1259         }
1260         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1261                 status = error("unable to unpack %s header",
1262                                sha1_to_hex(sha1));
1263         if (parse_sha1_header(hdr, type, &size) < 0)
1264                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1265         else {
1266                 status = 0;
1267                 if (sizep)
1268                         *sizep = size;
1269         }
1270         inflateEnd(&stream);
1271         munmap(map, mapsize);
1272         return status;
1273 }
1274
1275 static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
1276 {
1277         struct pack_entry e;
1278
1279         if (!find_pack_entry(sha1, &e)) {
1280                 error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1281                 return NULL;
1282         }
1283         return unpack_entry(&e, type, size);
1284 }
1285
1286 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
1287 {
1288         unsigned long mapsize;
1289         void *map, *buf;
1290         struct pack_entry e;
1291
1292         if (find_pack_entry(sha1, &e))
1293                 return read_packed_sha1(sha1, type, size);
1294         map = map_sha1_file_internal(sha1, &mapsize);
1295         if (map) {
1296                 buf = unpack_sha1_file(map, mapsize, type, size);
1297                 munmap(map, mapsize);
1298                 return buf;
1299         }
1300         reprepare_packed_git();
1301         if (find_pack_entry(sha1, &e))
1302                 return read_packed_sha1(sha1, type, size);
1303         return NULL;
1304 }
1305
1306 void *read_object_with_reference(const unsigned char *sha1,
1307                                  const char *required_type,
1308                                  unsigned long *size,
1309                                  unsigned char *actual_sha1_return)
1310 {
1311         char type[20];
1312         void *buffer;
1313         unsigned long isize;
1314         unsigned char actual_sha1[20];
1315
1316         memcpy(actual_sha1, sha1, 20);
1317         while (1) {
1318                 int ref_length = -1;
1319                 const char *ref_type = NULL;
1320
1321                 buffer = read_sha1_file(actual_sha1, type, &isize);
1322                 if (!buffer)
1323                         return NULL;
1324                 if (!strcmp(type, required_type)) {
1325                         *size = isize;
1326                         if (actual_sha1_return)
1327                                 memcpy(actual_sha1_return, actual_sha1, 20);
1328                         return buffer;
1329                 }
1330                 /* Handle references */
1331                 else if (!strcmp(type, commit_type))
1332                         ref_type = "tree ";
1333                 else if (!strcmp(type, tag_type))
1334                         ref_type = "object ";
1335                 else {
1336                         free(buffer);
1337                         return NULL;
1338                 }
1339                 ref_length = strlen(ref_type);
1340
1341                 if (memcmp(buffer, ref_type, ref_length) ||
1342                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1343                         free(buffer);
1344                         return NULL;
1345                 }
1346                 free(buffer);
1347                 /* Now we have the ID of the referred-to object in
1348                  * actual_sha1.  Check again. */
1349         }
1350 }
1351
1352 char *write_sha1_file_prepare(void *buf,
1353                               unsigned long len,
1354                               const char *type,
1355                               unsigned char *sha1,
1356                               unsigned char *hdr,
1357                               int *hdrlen)
1358 {
1359         SHA_CTX c;
1360
1361         /* Generate the header */
1362         *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
1363
1364         /* Sha1.. */
1365         SHA1_Init(&c);
1366         SHA1_Update(&c, hdr, *hdrlen);
1367         SHA1_Update(&c, buf, len);
1368         SHA1_Final(sha1, &c);
1369
1370         return sha1_file_name(sha1);
1371 }
1372
1373 /*
1374  * Link the tempfile to the final place, possibly creating the
1375  * last directory level as you do so.
1376  *
1377  * Returns the errno on failure, 0 on success.
1378  */
1379 static int link_temp_to_file(const char *tmpfile, char *filename)
1380 {
1381         int ret;
1382         char *dir;
1383
1384         if (!link(tmpfile, filename))
1385                 return 0;
1386
1387         /*
1388          * Try to mkdir the last path component if that failed.
1389          *
1390          * Re-try the "link()" regardless of whether the mkdir
1391          * succeeds, since a race might mean that somebody
1392          * else succeeded.
1393          */
1394         ret = errno;
1395         dir = strrchr(filename, '/');
1396         if (dir) {
1397                 *dir = 0;
1398                 mkdir(filename, 0777);
1399                 if (adjust_shared_perm(filename))
1400                         return -2;
1401                 *dir = '/';
1402                 if (!link(tmpfile, filename))
1403                         return 0;
1404                 ret = errno;
1405         }
1406         return ret;
1407 }
1408
1409 /*
1410  * Move the just written object into its final resting place
1411  */
1412 int move_temp_to_file(const char *tmpfile, char *filename)
1413 {
1414         int ret = link_temp_to_file(tmpfile, filename);
1415
1416         /*
1417          * Coda hack - coda doesn't like cross-directory links,
1418          * so we fall back to a rename, which will mean that it
1419          * won't be able to check collisions, but that's not a
1420          * big deal.
1421          *
1422          * The same holds for FAT formatted media.
1423          *
1424          * When this succeeds, we just return 0. We have nothing
1425          * left to unlink.
1426          */
1427         if (ret && ret != EEXIST) {
1428                 if (!rename(tmpfile, filename))
1429                         return 0;
1430                 ret = errno;
1431         }
1432         unlink(tmpfile);
1433         if (ret) {
1434                 if (ret != EEXIST) {
1435                         fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
1436                         return -1;
1437                 }
1438                 /* FIXME!!! Collision check here ? */
1439         }
1440
1441         return 0;
1442 }
1443
1444 static int write_buffer(int fd, const void *buf, size_t len)
1445 {
1446         while (len) {
1447                 ssize_t size;
1448
1449                 size = write(fd, buf, len);
1450                 if (!size)
1451                         return error("file write: disk full");
1452                 if (size < 0) {
1453                         if (errno == EINTR || errno == EAGAIN)
1454                                 continue;
1455                         return error("file write error (%s)", strerror(errno));
1456                 }
1457                 len -= size;
1458                 buf = (char *) buf + size;
1459         }
1460         return 0;
1461 }
1462
1463 static int write_binary_header(unsigned char *hdr, enum object_type type, unsigned long len)
1464 {
1465         int hdr_len;
1466         unsigned char c;
1467
1468         c = (type << 4) | (len & 15);
1469         len >>= 4;
1470         hdr_len = 1;
1471         while (len) {
1472                 *hdr++ = c | 0x80;
1473                 hdr_len++;
1474                 c = (len & 0x7f);
1475                 len >>= 7;
1476         }
1477         *hdr = c;
1478         return hdr_len;
1479 }
1480
1481 static void setup_object_header(z_stream *stream, const char *type, unsigned long len)
1482 {
1483         int obj_type, hdr;
1484
1485         if (use_legacy_headers) {
1486                 while (deflate(stream, 0) == Z_OK)
1487                         /* nothing */;
1488                 return;
1489         }
1490         if (!strcmp(type, blob_type))
1491                 obj_type = OBJ_BLOB;
1492         else if (!strcmp(type, tree_type))
1493                 obj_type = OBJ_TREE;
1494         else if (!strcmp(type, commit_type))
1495                 obj_type = OBJ_COMMIT;
1496         else if (!strcmp(type, tag_type))
1497                 obj_type = OBJ_TAG;
1498         else
1499                 die("trying to generate bogus object of type '%s'", type);
1500         hdr = write_binary_header(stream->next_out, obj_type, len);
1501         stream->total_out = hdr;
1502         stream->next_out += hdr;
1503         stream->avail_out -= hdr;
1504 }
1505
1506 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
1507 {
1508         int size;
1509         unsigned char *compressed;
1510         z_stream stream;
1511         unsigned char sha1[20];
1512         char *filename;
1513         static char tmpfile[PATH_MAX];
1514         unsigned char hdr[50];
1515         int fd, hdrlen;
1516
1517         /* Normally if we have it in the pack then we do not bother writing
1518          * it out into .git/objects/??/?{38} file.
1519          */
1520         filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1521         if (returnsha1)
1522                 memcpy(returnsha1, sha1, 20);
1523         if (has_sha1_file(sha1))
1524                 return 0;
1525         fd = open(filename, O_RDONLY);
1526         if (fd >= 0) {
1527                 /*
1528                  * FIXME!!! We might do collision checking here, but we'd
1529                  * need to uncompress the old file and check it. Later.
1530                  */
1531                 close(fd);
1532                 return 0;
1533         }
1534
1535         if (errno != ENOENT) {
1536                 fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
1537                 return -1;
1538         }
1539
1540         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1541
1542         fd = mkstemp(tmpfile);
1543         if (fd < 0) {
1544                 fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
1545                 return -1;
1546         }
1547
1548         /* Set it up */
1549         memset(&stream, 0, sizeof(stream));
1550         deflateInit(&stream, zlib_compression_level);
1551         size = 8 + deflateBound(&stream, len+hdrlen);
1552         compressed = xmalloc(size);
1553
1554         /* Compress it */
1555         stream.next_out = compressed;
1556         stream.avail_out = size;
1557
1558         /* First header.. */
1559         stream.next_in = hdr;
1560         stream.avail_in = hdrlen;
1561         setup_object_header(&stream, type, len);
1562
1563         /* Then the data itself.. */
1564         stream.next_in = buf;
1565         stream.avail_in = len;
1566         while (deflate(&stream, Z_FINISH) == Z_OK)
1567                 /* nothing */;
1568         deflateEnd(&stream);
1569         size = stream.total_out;
1570
1571         if (write_buffer(fd, compressed, size) < 0)
1572                 die("unable to write sha1 file");
1573         fchmod(fd, 0444);
1574         close(fd);
1575         free(compressed);
1576
1577         return move_temp_to_file(tmpfile, filename);
1578 }
1579
1580 /*
1581  * We need to unpack and recompress the object for writing
1582  * it out to a different file.
1583  */
1584 static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
1585 {
1586         size_t size;
1587         z_stream stream;
1588         unsigned char *unpacked;
1589         unsigned long len;
1590         char type[20];
1591         char hdr[50];
1592         int hdrlen;
1593         void *buf;
1594
1595         /* need to unpack and recompress it by itself */
1596         unpacked = read_packed_sha1(sha1, type, &len);
1597
1598         hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
1599
1600         /* Set it up */
1601         memset(&stream, 0, sizeof(stream));
1602         deflateInit(&stream, zlib_compression_level);
1603         size = deflateBound(&stream, len + hdrlen);
1604         buf = xmalloc(size);
1605
1606         /* Compress it */
1607         stream.next_out = buf;
1608         stream.avail_out = size;
1609
1610         /* First header.. */
1611         stream.next_in = (void *)hdr;
1612         stream.avail_in = hdrlen;
1613         while (deflate(&stream, 0) == Z_OK)
1614                 /* nothing */;
1615
1616         /* Then the data itself.. */
1617         stream.next_in = unpacked;
1618         stream.avail_in = len;
1619         while (deflate(&stream, Z_FINISH) == Z_OK)
1620                 /* nothing */;
1621         deflateEnd(&stream);
1622         free(unpacked);
1623
1624         *objsize = stream.total_out;
1625         return buf;
1626 }
1627
1628 int write_sha1_to_fd(int fd, const unsigned char *sha1)
1629 {
1630         int retval;
1631         unsigned long objsize;
1632         void *buf = map_sha1_file_internal(sha1, &objsize);
1633
1634         if (buf) {
1635                 retval = write_buffer(fd, buf, objsize);
1636                 munmap(buf, objsize);
1637                 return retval;
1638         }
1639
1640         buf = repack_object(sha1, &objsize);
1641         retval = write_buffer(fd, buf, objsize);
1642         free(buf);
1643         return retval;
1644 }
1645
1646 int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
1647                        size_t bufsize, size_t *bufposn)
1648 {
1649         char tmpfile[PATH_MAX];
1650         int local;
1651         z_stream stream;
1652         unsigned char real_sha1[20];
1653         unsigned char discard[4096];
1654         int ret;
1655         SHA_CTX c;
1656
1657         snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
1658
1659         local = mkstemp(tmpfile);
1660         if (local < 0)
1661                 return error("Couldn't open %s for %s",
1662                              tmpfile, sha1_to_hex(sha1));
1663
1664         memset(&stream, 0, sizeof(stream));
1665
1666         inflateInit(&stream);
1667
1668         SHA1_Init(&c);
1669
1670         do {
1671                 ssize_t size;
1672                 if (*bufposn) {
1673                         stream.avail_in = *bufposn;
1674                         stream.next_in = (unsigned char *) buffer;
1675                         do {
1676                                 stream.next_out = discard;
1677                                 stream.avail_out = sizeof(discard);
1678                                 ret = inflate(&stream, Z_SYNC_FLUSH);
1679                                 SHA1_Update(&c, discard, sizeof(discard) -
1680                                             stream.avail_out);
1681                         } while (stream.avail_in && ret == Z_OK);
1682                         if (write_buffer(local, buffer, *bufposn - stream.avail_in) < 0)
1683                                 die("unable to write sha1 file");
1684                         memmove(buffer, buffer + *bufposn - stream.avail_in,
1685                                 stream.avail_in);
1686                         *bufposn = stream.avail_in;
1687                         if (ret != Z_OK)
1688                                 break;
1689                 }
1690                 size = read(fd, buffer + *bufposn, bufsize - *bufposn);
1691                 if (size <= 0) {
1692                         close(local);
1693                         unlink(tmpfile);
1694                         if (!size)
1695                                 return error("Connection closed?");
1696                         perror("Reading from connection");
1697                         return -1;
1698                 }
1699                 *bufposn += size;
1700         } while (1);
1701         inflateEnd(&stream);
1702
1703         close(local);
1704         SHA1_Final(real_sha1, &c);
1705         if (ret != Z_STREAM_END) {
1706                 unlink(tmpfile);
1707                 return error("File %s corrupted", sha1_to_hex(sha1));
1708         }
1709         if (memcmp(sha1, real_sha1, 20)) {
1710                 unlink(tmpfile);
1711                 return error("File %s has bad hash", sha1_to_hex(sha1));
1712         }
1713
1714         return move_temp_to_file(tmpfile, sha1_file_name(sha1));
1715 }
1716
1717 int has_pack_index(const unsigned char *sha1)
1718 {
1719         struct stat st;
1720         if (stat(sha1_pack_index_name(sha1), &st))
1721                 return 0;
1722         return 1;
1723 }
1724
1725 int has_pack_file(const unsigned char *sha1)
1726 {
1727         struct stat st;
1728         if (stat(sha1_pack_name(sha1), &st))
1729                 return 0;
1730         return 1;
1731 }
1732
1733 int has_sha1_pack(const unsigned char *sha1)
1734 {
1735         struct pack_entry e;
1736         return find_pack_entry(sha1, &e);
1737 }
1738
1739 int has_sha1_file(const unsigned char *sha1)
1740 {
1741         struct stat st;
1742         struct pack_entry e;
1743
1744         if (find_pack_entry(sha1, &e))
1745                 return 1;
1746         return find_sha1_file(sha1, &st) ? 1 : 0;
1747 }
1748
1749 /*
1750  * reads from fd as long as possible into a supplied buffer of size bytes.
1751  * If necessary the buffer's size is increased using realloc()
1752  *
1753  * returns 0 if anything went fine and -1 otherwise
1754  *
1755  * NOTE: both buf and size may change, but even when -1 is returned
1756  * you still have to free() it yourself.
1757  */
1758 int read_pipe(int fd, char** return_buf, unsigned long* return_size)
1759 {
1760         char* buf = *return_buf;
1761         unsigned long size = *return_size;
1762         int iret;
1763         unsigned long off = 0;
1764
1765         do {
1766                 iret = xread(fd, buf + off, size - off);
1767                 if (iret > 0) {
1768                         off += iret;
1769                         if (off == size) {
1770                                 size *= 2;
1771                                 buf = realloc(buf, size);
1772                         }
1773                 }
1774         } while (iret > 0);
1775
1776         *return_buf = buf;
1777         *return_size = off;
1778
1779         if (iret < 0)
1780                 return -1;
1781         return 0;
1782 }
1783
1784 int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
1785 {
1786         unsigned long size = 4096;
1787         char *buf = malloc(size);
1788         int ret;
1789         unsigned char hdr[50];
1790         int hdrlen;
1791
1792         if (read_pipe(fd, &buf, &size)) {
1793                 free(buf);
1794                 return -1;
1795         }
1796
1797         if (!type)
1798                 type = blob_type;
1799         if (write_object)
1800                 ret = write_sha1_file(buf, size, type, sha1);
1801         else {
1802                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1803                 ret = 0;
1804         }
1805         free(buf);
1806         return ret;
1807 }
1808
1809 int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
1810 {
1811         unsigned long size = st->st_size;
1812         void *buf;
1813         int ret;
1814         unsigned char hdr[50];
1815         int hdrlen;
1816
1817         buf = "";
1818         if (size)
1819                 buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1820         close(fd);
1821         if (buf == MAP_FAILED)
1822                 return -1;
1823
1824         if (!type)
1825                 type = blob_type;
1826         if (write_object)
1827                 ret = write_sha1_file(buf, size, type, sha1);
1828         else {
1829                 write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
1830                 ret = 0;
1831         }
1832         if (size)
1833                 munmap(buf, size);
1834         return ret;
1835 }
1836
1837 int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
1838 {
1839         int fd;
1840         char *target;
1841
1842         switch (st->st_mode & S_IFMT) {
1843         case S_IFREG:
1844                 fd = open(path, O_RDONLY);
1845                 if (fd < 0)
1846                         return error("open(\"%s\"): %s", path,
1847                                      strerror(errno));
1848                 if (index_fd(sha1, fd, st, write_object, NULL) < 0)
1849                         return error("%s: failed to insert into database",
1850                                      path);
1851                 break;
1852         case S_IFLNK:
1853                 target = xmalloc(st->st_size+1);
1854                 if (readlink(path, target, st->st_size+1) != st->st_size) {
1855                         char *errstr = strerror(errno);
1856                         free(target);
1857                         return error("readlink(\"%s\"): %s", path,
1858                                      errstr);
1859                 }
1860                 if (!write_object) {
1861                         unsigned char hdr[50];
1862                         int hdrlen;
1863                         write_sha1_file_prepare(target, st->st_size, blob_type,
1864                                                 sha1, hdr, &hdrlen);
1865                 } else if (write_sha1_file(target, st->st_size, blob_type, sha1))
1866                         return error("%s: failed to insert into database",
1867                                      path);
1868                 free(target);
1869                 break;
1870         default:
1871                 return error("%s: unsupported file type", path);
1872         }
1873         return 0;
1874 }