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