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 "config.h"
  11 #include "string-list.h"
  12 #include "lockfile.h"
  13 #include "delta.h"
  14 #include "pack.h"
  15 #include "blob.h"
  16 #include "commit.h"
  17 #include "run-command.h"
  18 #include "tag.h"
  19 #include "tree.h"
  20 #include "tree-walk.h"
  21 #include "refs.h"
  22 #include "pack-revindex.h"
  23 #include "sha1-lookup.h"
  24 #include "bulk-checkin.h"
  25 #include "streaming.h"
  26 #include "dir.h"
  27 #include "mru.h"
  28 #include "list.h"
  29 #include "mergesort.h"
  30 #include "quote.h"
  31 #include "packfile.h"
  32
  33 const unsigned char null_sha1[20];
  34 const struct object_id null_oid;
  35 const struct object_id empty_tree_oid = {
  36         EMPTY_TREE_SHA1_BIN_LITERAL
  37 };
  38 const struct object_id empty_blob_oid = {
  39         EMPTY_BLOB_SHA1_BIN_LITERAL
  40 };
  41
  42 /*
  43  * This is meant to hold a *small* number of objects that you would
  44  * want read_sha1_file() to be able to return, but yet you do not want
  45  * to write them into the object store (e.g. a browse-only
  46  * application).
  47  */
  48 static struct cached_object {
  49         unsigned char sha1[20];
  50         enum object_type type;
  51         void *buf;
  52         unsigned long size;
  53 } *cached_objects;
  54 static int cached_object_nr, cached_object_alloc;
  55
  56 static struct cached_object empty_tree = {
  57         EMPTY_TREE_SHA1_BIN_LITERAL,
  58         OBJ_TREE,
  59         "",
  60         0
  61 };
  62
  63 static struct cached_object *find_cached_object(const unsigned char *sha1)
  64 {
  65         int i;
  66         struct cached_object *co = cached_objects;
  67
  68         for (i = 0; i < cached_object_nr; i++, co++) {
  69                 if (!hashcmp(co->sha1, sha1))
  70                         return co;
  71         }
  72         if (!hashcmp(sha1, empty_tree.sha1))
  73                 return &empty_tree;
  74         return NULL;
  75 }
  76
  77 int mkdir_in_gitdir(const char *path)
  78 {
  79         if (mkdir(path, 0777)) {
  80                 int saved_errno = errno;
  81                 struct stat st;
  82                 struct strbuf sb = STRBUF_INIT;
  83
  84                 if (errno != EEXIST)
  85                         return -1;
  86                 /*
  87                  * Are we looking at a path in a symlinked worktree
  88                  * whose original repository does not yet have it?
  89                  * e.g. .git/rr-cache pointing at its original
  90                  * repository in which the user hasn't performed any
  91                  * conflict resolution yet?
  92                  */
  93                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
  94                     strbuf_readlink(&sb, path, st.st_size) ||
  95                     !is_absolute_path(sb.buf) ||
  96                     mkdir(sb.buf, 0777)) {
  97                         strbuf_release(&sb);
  98                         errno = saved_errno;
  99                         return -1;
 100                 }
 101                 strbuf_release(&sb);
 102         }
 103         return adjust_shared_perm(path);
 104 }
 105
 106 enum scld_error safe_create_leading_directories(char *path)
 107 {
 108         char *next_component = path + offset_1st_component(path);
 109         enum scld_error ret = SCLD_OK;
 110
 111         while (ret == SCLD_OK && next_component) {
 112                 struct stat st;
 113                 char *slash = next_component, slash_character;
 114
 115                 while (*slash && !is_dir_sep(*slash))
 116                         slash++;
 117
 118                 if (!*slash)
 119                         break;
 120
 121                 next_component = slash + 1;
 122                 while (is_dir_sep(*next_component))
 123                         next_component++;
 124                 if (!*next_component)
 125                         break;
 126
 127                 slash_character = *slash;
 128                 *slash = '\0';
 129                 if (!stat(path, &st)) {
 130                         /* path exists */
 131                         if (!S_ISDIR(st.st_mode)) {
 132                                 errno = ENOTDIR;
 133                                 ret = SCLD_EXISTS;
 134                         }
 135                 } else if (mkdir(path, 0777)) {
 136                         if (errno == EEXIST &&
 137                             !stat(path, &st) && S_ISDIR(st.st_mode))
 138                                 ; /* somebody created it since we checked */
 139                         else if (errno == ENOENT)
 140                                 /*
 141                                  * Either mkdir() failed because
 142                                  * somebody just pruned the containing
 143                                  * directory, or stat() failed because
 144                                  * the file that was in our way was
 145                                  * just removed.  Either way, inform
 146                                  * the caller that it might be worth
 147                                  * trying again:
 148                                  */
 149                                 ret = SCLD_VANISHED;
 150                         else
 151                                 ret = SCLD_FAILED;
 152                 } else if (adjust_shared_perm(path)) {
 153                         ret = SCLD_PERMS;
 154                 }
 155                 *slash = slash_character;
 156         }
 157         return ret;
 158 }
 159
 160 enum scld_error safe_create_leading_directories_const(const char *path)
 161 {
 162         int save_errno;
 163         /* path points to cache entries, so xstrdup before messing with it */
 164         char *buf = xstrdup(path);
 165         enum scld_error result = safe_create_leading_directories(buf);
 166
 167         save_errno = errno;
 168         free(buf);
 169         errno = save_errno;
 170         return result;
 171 }
 172
 173 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 174 {
 175         /*
 176          * The number of times we will try to remove empty directories
 177          * in the way of path. This is only 1 because if another
 178          * process is racily creating directories that conflict with
 179          * us, we don't want to fight against them.
 180          */
 181         int remove_directories_remaining = 1;
 182
 183         /*
 184          * The number of times that we will try to create the
 185          * directories containing path. We are willing to attempt this
 186          * more than once, because another process could be trying to
 187          * clean up empty directories at the same time as we are
 188          * trying to create them.
 189          */
 190         int create_directories_remaining = 3;
 191
 192         /* A scratch copy of path, filled lazily if we need it: */
 193         struct strbuf path_copy = STRBUF_INIT;
 194
 195         int ret, save_errno;
 196
 197         /* Sanity check: */
 198         assert(*path);
 199
 200 retry_fn:
 201         ret = fn(path, cb);
 202         save_errno = errno;
 203         if (!ret)
 204                 goto out;
 205
 206         if (errno == EISDIR && remove_directories_remaining-- > 0) {
 207                 /*
 208                  * A directory is in the way. Maybe it is empty; try
 209                  * to remove it:
 210                  */
 211                 if (!path_copy.len)
 212                         strbuf_addstr(&path_copy, path);
 213
 214                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 215                         goto retry_fn;
 216         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 217                 /*
 218                  * Maybe the containing directory didn't exist, or
 219                  * maybe it was just deleted by a process that is
 220                  * racing with us to clean up empty directories. Try
 221                  * to create it:
 222                  */
 223                 enum scld_error scld_result;
 224
 225                 if (!path_copy.len)
 226                         strbuf_addstr(&path_copy, path);
 227
 228                 do {
 229                         scld_result = safe_create_leading_directories(path_copy.buf);
 230                         if (scld_result == SCLD_OK)
 231                                 goto retry_fn;
 232                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 233         }
 234
 235 out:
 236         strbuf_release(&path_copy);
 237         errno = save_errno;
 238         return ret;
 239 }
 240
 241 static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 242 {
 243         int i;
 244         for (i = 0; i < 20; i++) {
 245                 static char hex[] = "0123456789abcdef";
 246                 unsigned int val = sha1[i];
 247                 strbuf_addch(buf, hex[val >> 4]);
 248                 strbuf_addch(buf, hex[val & 0xf]);
 249                 if (!i)
 250                         strbuf_addch(buf, '/');
 251         }
 252 }
 253
 254 const char *sha1_file_name(const unsigned char *sha1)
 255 {
 256         static struct strbuf buf = STRBUF_INIT;
 257
 258         strbuf_reset(&buf);
 259         strbuf_addf(&buf, "%s/", get_object_directory());
 260
 261         fill_sha1_path(&buf, sha1);
 262         return buf.buf;
 263 }
 264
 265 struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 266 {
 267         strbuf_setlen(&alt->scratch, alt->base_len);
 268         return &alt->scratch;
 269 }
 270
 271 static const char *alt_sha1_path(struct alternate_object_database *alt,
 272                                  const unsigned char *sha1)
 273 {
 274         struct strbuf *buf = alt_scratch_buf(alt);
 275         fill_sha1_path(buf, sha1);
 276         return buf->buf;
 277 }
 278
 279 struct alternate_object_database *alt_odb_list;
 280 static struct alternate_object_database **alt_odb_tail;
 281
 282 /*
 283  * Return non-zero iff the path is usable as an alternate object database.
 284  */
 285 static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 286 {
 287         struct alternate_object_database *alt;
 288
 289         /* Detect cases where alternate disappeared */
 290         if (!is_directory(path->buf)) {
 291                 error("object directory %s does not exist; "
 292                       "check .git/objects/info/alternates.",
 293                       path->buf);
 294                 return 0;
 295         }
 296
 297         /*
 298          * Prevent the common mistake of listing the same
 299          * thing twice, or object directory itself.
 300          */
 301         for (alt = alt_odb_list; alt; alt = alt->next) {
 302                 if (!fspathcmp(path->buf, alt->path))
 303                         return 0;
 304         }
 305         if (!fspathcmp(path->buf, normalized_objdir))
 306                 return 0;
 307
 308         return 1;
 309 }
 310
 311 /*
 312  * Prepare alternate object database registry.
 313  *
 314  * The variable alt_odb_list points at the list of struct
 315  * alternate_object_database.  The elements on this list come from
 316  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 317  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 318  * whose contents is similar to that environment variable but can be
 319  * LF separated.  Its base points at a statically allocated buffer that
 320  * contains "/the/directory/corresponding/to/.git/objects/...", while
 321  * its name points just after the slash at the end of ".git/objects/"
 322  * in the example above, and has enough space to hold 40-byte hex
 323  * SHA1, an extra slash for the first level indirection, and the
 324  * terminating NUL.
 325  */
 326 static void read_info_alternates(const char * relative_base, int depth);
 327 static int link_alt_odb_entry(const char *entry, const char *relative_base,
 328         int depth, const char *normalized_objdir)
 329 {
 330         struct alternate_object_database *ent;
 331         struct strbuf pathbuf = STRBUF_INIT;
 332
 333         if (!is_absolute_path(entry) && relative_base) {
 334                 strbuf_realpath(&pathbuf, relative_base, 1);
 335                 strbuf_addch(&pathbuf, '/');
 336         }
 337         strbuf_addstr(&pathbuf, entry);
 338
 339         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 340                 error("unable to normalize alternate object path: %s",
 341                       pathbuf.buf);
 342                 strbuf_release(&pathbuf);
 343                 return -1;
 344         }
 345
 346         /*
 347          * The trailing slash after the directory name is given by
 348          * this function at the end. Remove duplicates.
 349          */
 350         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 351                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
 352
 353         if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 354                 strbuf_release(&pathbuf);
 355                 return -1;
 356         }
 357
 358         ent = alloc_alt_odb(pathbuf.buf);
 359
 360         /* add the alternate entry */
 361         *alt_odb_tail = ent;
 362         alt_odb_tail = &(ent->next);
 363         ent->next = NULL;
 364
 365         /* recursively add alternates */
 366         read_info_alternates(pathbuf.buf, depth + 1);
 367
 368         strbuf_release(&pathbuf);
 369         return 0;
 370 }
 371
 372 static const char *parse_alt_odb_entry(const char *string,
 373                                        int sep,
 374                                        struct strbuf *out)
 375 {
 376         const char *end;
 377
 378         strbuf_reset(out);
 379
 380         if (*string == '#') {
 381                 /* comment; consume up to next separator */
 382                 end = strchrnul(string, sep);
 383         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 384                 /*
 385                  * quoted path; unquote_c_style has copied the
 386                  * data for us and set "end". Broken quoting (e.g.,
 387                  * an entry that doesn't end with a quote) falls
 388                  * back to the unquoted case below.
 389                  */
 390         } else {
 391                 /* normal, unquoted path */
 392                 end = strchrnul(string, sep);
 393                 strbuf_add(out, string, end - string);
 394         }
 395
 396         if (*end)
 397                 end++;
 398         return end;
 399 }
 400
 401 static void link_alt_odb_entries(const char *alt, int len, int sep,
 402                                  const char *relative_base, int depth)
 403 {
 404         struct strbuf objdirbuf = STRBUF_INIT;
 405         struct strbuf entry = STRBUF_INIT;
 406
 407         if (depth > 5) {
 408                 error("%s: ignoring alternate object stores, nesting too deep.",
 409                                 relative_base);
 410                 return;
 411         }
 412
 413         strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 414         if (strbuf_normalize_path(&objdirbuf) < 0)
 415                 die("unable to normalize object directory: %s",
 416                     objdirbuf.buf);
 417
 418         while (*alt) {
 419                 alt = parse_alt_odb_entry(alt, sep, &entry);
 420                 if (!entry.len)
 421                         continue;
 422                 link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 423         }
 424         strbuf_release(&entry);
 425         strbuf_release(&objdirbuf);
 426 }
 427
 428 static void read_info_alternates(const char * relative_base, int depth)
 429 {
 430         char *map;
 431         size_t mapsz;
 432         struct stat st;
 433         char *path;
 434         int fd;
 435
 436         path = xstrfmt("%s/info/alternates", relative_base);
 437         fd = git_open(path);
 438         free(path);
 439         if (fd < 0)
 440                 return;
 441         if (fstat(fd, &st) || (st.st_size == 0)) {
 442                 close(fd);
 443                 return;
 444         }
 445         mapsz = xsize_t(st.st_size);
 446         map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 447         close(fd);
 448
 449         link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
 450
 451         munmap(map, mapsz);
 452 }
 453
 454 struct alternate_object_database *alloc_alt_odb(const char *dir)
 455 {
 456         struct alternate_object_database *ent;
 457
 458         FLEX_ALLOC_STR(ent, path, dir);
 459         strbuf_init(&ent->scratch, 0);
 460         strbuf_addf(&ent->scratch, "%s/", dir);
 461         ent->base_len = ent->scratch.len;
 462
 463         return ent;
 464 }
 465
 466 void add_to_alternates_file(const char *reference)
 467 {
 468         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 469         char *alts = git_pathdup("objects/info/alternates");
 470         FILE *in, *out;
 471
 472         hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
 473         out = fdopen_lock_file(lock, "w");
 474         if (!out)
 475                 die_errno("unable to fdopen alternates lockfile");
 476
 477         in = fopen(alts, "r");
 478         if (in) {
 479                 struct strbuf line = STRBUF_INIT;
 480                 int found = 0;
 481
 482                 while (strbuf_getline(&line, in) != EOF) {
 483                         if (!strcmp(reference, line.buf)) {
 484                                 found = 1;
 485                                 break;
 486                         }
 487                         fprintf_or_die(out, "%s\n", line.buf);
 488                 }
 489
 490                 strbuf_release(&line);
 491                 fclose(in);
 492
 493                 if (found) {
 494                         rollback_lock_file(lock);
 495                         lock = NULL;
 496                 }
 497         }
 498         else if (errno != ENOENT)
 499                 die_errno("unable to read alternates file");
 500
 501         if (lock) {
 502                 fprintf_or_die(out, "%s\n", reference);
 503                 if (commit_lock_file(lock))
 504                         die_errno("unable to move new alternates file into place");
 505                 if (alt_odb_tail)
 506                         link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 507         }
 508         free(alts);
 509 }
 510
 511 void add_to_alternates_memory(const char *reference)
 512 {
 513         /*
 514          * Make sure alternates are initialized, or else our entry may be
 515          * overwritten when they are.
 516          */
 517         prepare_alt_odb();
 518
 519         link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 520 }
 521
 522 /*
 523  * Compute the exact path an alternate is at and returns it. In case of
 524  * error NULL is returned and the human readable error is added to `err`
 525  * `path` may be relative and should point to $GITDIR.
 526  * `err` must not be null.
 527  */
 528 char *compute_alternate_path(const char *path, struct strbuf *err)
 529 {
 530         char *ref_git = NULL;
 531         const char *repo, *ref_git_s;
 532         int seen_error = 0;
 533
 534         ref_git_s = real_path_if_valid(path);
 535         if (!ref_git_s) {
 536                 seen_error = 1;
 537                 strbuf_addf(err, _("path '%s' does not exist"), path);
 538                 goto out;
 539         } else
 540                 /*
 541                  * Beware: read_gitfile(), real_path() and mkpath()
 542                  * return static buffer
 543                  */
 544                 ref_git = xstrdup(ref_git_s);
 545
 546         repo = read_gitfile(ref_git);
 547         if (!repo)
 548                 repo = read_gitfile(mkpath("%s/.git", ref_git));
 549         if (repo) {
 550                 free(ref_git);
 551                 ref_git = xstrdup(repo);
 552         }
 553
 554         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 555                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
 556                 free(ref_git);
 557                 ref_git = ref_git_git;
 558         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 559                 struct strbuf sb = STRBUF_INIT;
 560                 seen_error = 1;
 561                 if (get_common_dir(&sb, ref_git)) {
 562                         strbuf_addf(err,
 563                                     _("reference repository '%s' as a linked "
 564                                       "checkout is not supported yet."),
 565                                     path);
 566                         goto out;
 567                 }
 568
 569                 strbuf_addf(err, _("reference repository '%s' is not a "
 570                                         "local repository."), path);
 571                 goto out;
 572         }
 573
 574         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 575                 strbuf_addf(err, _("reference repository '%s' is shallow"),
 576                             path);
 577                 seen_error = 1;
 578                 goto out;
 579         }
 580
 581         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 582                 strbuf_addf(err,
 583                             _("reference repository '%s' is grafted"),
 584                             path);
 585                 seen_error = 1;
 586                 goto out;
 587         }
 588
 589 out:
 590         if (seen_error) {
 591                 FREE_AND_NULL(ref_git);
 592         }
 593
 594         return ref_git;
 595 }
 596
 597 int foreach_alt_odb(alt_odb_fn fn, void *cb)
 598 {
 599         struct alternate_object_database *ent;
 600         int r = 0;
 601
 602         prepare_alt_odb();
 603         for (ent = alt_odb_list; ent; ent = ent->next) {
 604                 r = fn(ent, cb);
 605                 if (r)
 606                         break;
 607         }
 608         return r;
 609 }
 610
 611 void prepare_alt_odb(void)
 612 {
 613         const char *alt;
 614
 615         if (alt_odb_tail)
 616                 return;
 617
 618         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 619         if (!alt) alt = "";
 620
 621         alt_odb_tail = &alt_odb_list;
 622         link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
 623
 624         read_info_alternates(get_object_directory(), 0);
 625 }
 626
 627 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 628 static int freshen_file(const char *fn)
 629 {
 630         struct utimbuf t;
 631         t.actime = t.modtime = time(NULL);
 632         return !utime(fn, &t);
 633 }
 634
 635 /*
 636  * All of the check_and_freshen functions return 1 if the file exists and was
 637  * freshened (if freshening was requested), 0 otherwise. If they return
 638  * 0, you should not assume that it is safe to skip a write of the object (it
 639  * either does not exist on disk, or has a stale mtime and may be subject to
 640  * pruning).
 641  */
 642 int check_and_freshen_file(const char *fn, int freshen)
 643 {
 644         if (access(fn, F_OK))
 645                 return 0;
 646         if (freshen && !freshen_file(fn))
 647                 return 0;
 648         return 1;
 649 }
 650
 651 static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 652 {
 653         return check_and_freshen_file(sha1_file_name(sha1), freshen);
 654 }
 655
 656 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 657 {
 658         struct alternate_object_database *alt;
 659         prepare_alt_odb();
 660         for (alt = alt_odb_list; alt; alt = alt->next) {
 661                 const char *path = alt_sha1_path(alt, sha1);
 662                 if (check_and_freshen_file(path, freshen))
 663                         return 1;
 664         }
 665         return 0;
 666 }
 667
 668 static int check_and_freshen(const unsigned char *sha1, int freshen)
 669 {
 670         return check_and_freshen_local(sha1, freshen) ||
 671                check_and_freshen_nonlocal(sha1, freshen);
 672 }
 673
 674 int has_loose_object_nonlocal(const unsigned char *sha1)
 675 {
 676         return check_and_freshen_nonlocal(sha1, 0);
 677 }
 678
 679 static int has_loose_object(const unsigned char *sha1)
 680 {
 681         return check_and_freshen(sha1, 0);
 682 }
 683
 684 static void mmap_limit_check(size_t length)
 685 {
 686         static size_t limit = 0;
 687         if (!limit) {
 688                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 689                 if (!limit)
 690                         limit = SIZE_MAX;
 691         }
 692         if (length > limit)
 693                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 694                     (uintmax_t)length, (uintmax_t)limit);
 695 }
 696
 697 void *xmmap_gently(void *start, size_t length,
 698                   int prot, int flags, int fd, off_t offset)
 699 {
 700         void *ret;
 701
 702         mmap_limit_check(length);
 703         ret = mmap(start, length, prot, flags, fd, offset);
 704         if (ret == MAP_FAILED) {
 705                 if (!length)
 706                         return NULL;
 707                 release_pack_memory(length);
 708                 ret = mmap(start, length, prot, flags, fd, offset);
 709         }
 710         return ret;
 711 }
 712
 713 void *xmmap(void *start, size_t length,
 714         int prot, int flags, int fd, off_t offset)
 715 {
 716         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 717         if (ret == MAP_FAILED)
 718                 die_errno("mmap failed");
 719         return ret;
 720 }
 721
 722 /*
 723  * With an in-core object data in "map", rehash it to make sure the
 724  * object name actually matches "sha1" to detect object corruption.
 725  * With "map" == NULL, try reading the object named with "sha1" using
 726  * the streaming interface and rehash it to do the same.
 727  */
 728 int check_sha1_signature(const unsigned char *sha1, void *map,
 729                          unsigned long size, const char *type)
 730 {
 731         unsigned char real_sha1[20];
 732         enum object_type obj_type;
 733         struct git_istream *st;
 734         git_SHA_CTX c;
 735         char hdr[32];
 736         int hdrlen;
 737
 738         if (map) {
 739                 hash_sha1_file(map, size, type, real_sha1);
 740                 return hashcmp(sha1, real_sha1) ? -1 : 0;
 741         }
 742
 743         st = open_istream(sha1, &obj_type, &size, NULL);
 744         if (!st)
 745                 return -1;
 746
 747         /* Generate the header */
 748         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 749
 750         /* Sha1.. */
 751         git_SHA1_Init(&c);
 752         git_SHA1_Update(&c, hdr, hdrlen);
 753         for (;;) {
 754                 char buf[1024 * 16];
 755                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
 756
 757                 if (readlen < 0) {
 758                         close_istream(st);
 759                         return -1;
 760                 }
 761                 if (!readlen)
 762                         break;
 763                 git_SHA1_Update(&c, buf, readlen);
 764         }
 765         git_SHA1_Final(real_sha1, &c);
 766         close_istream(st);
 767         return hashcmp(sha1, real_sha1) ? -1 : 0;
 768 }
 769
 770 int git_open_cloexec(const char *name, int flags)
 771 {
 772         int fd;
 773         static int o_cloexec = O_CLOEXEC;
 774
 775         fd = open(name, flags | o_cloexec);
 776         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 777                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
 778                 o_cloexec &= ~O_CLOEXEC;
 779                 fd = open(name, flags | o_cloexec);
 780         }
 781
 782 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 783         {
 784                 static int fd_cloexec = FD_CLOEXEC;
 785
 786                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
 787                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 788                         int flags = fcntl(fd, F_GETFD);
 789                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 790                                 fd_cloexec = 0;
 791                 }
 792         }
 793 #endif
 794         return fd;
 795 }
 796
 797 /*
 798  * Find "sha1" as a loose object in the local repository or in an alternate.
 799  * Returns 0 on success, negative on failure.
 800  *
 801  * The "path" out-parameter will give the path of the object we found (if any).
 802  * Note that it may point to static storage and is only valid until another
 803  * call to sha1_file_name(), etc.
 804  */
 805 static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 806                           const char **path)
 807 {
 808         struct alternate_object_database *alt;
 809
 810         *path = sha1_file_name(sha1);
 811         if (!lstat(*path, st))
 812                 return 0;
 813
 814         prepare_alt_odb();
 815         errno = ENOENT;
 816         for (alt = alt_odb_list; alt; alt = alt->next) {
 817                 *path = alt_sha1_path(alt, sha1);
 818                 if (!lstat(*path, st))
 819                         return 0;
 820         }
 821
 822         return -1;
 823 }
 824
 825 /*
 826  * Like stat_sha1_file(), but actually open the object and return the
 827  * descriptor. See the caveats on the "path" parameter above.
 828  */
 829 static int open_sha1_file(const unsigned char *sha1, const char **path)
 830 {
 831         int fd;
 832         struct alternate_object_database *alt;
 833         int most_interesting_errno;
 834
 835         *path = sha1_file_name(sha1);
 836         fd = git_open(*path);
 837         if (fd >= 0)
 838                 return fd;
 839         most_interesting_errno = errno;
 840
 841         prepare_alt_odb();
 842         for (alt = alt_odb_list; alt; alt = alt->next) {
 843                 *path = alt_sha1_path(alt, sha1);
 844                 fd = git_open(*path);
 845                 if (fd >= 0)
 846                         return fd;
 847                 if (most_interesting_errno == ENOENT)
 848                         most_interesting_errno = errno;
 849         }
 850         errno = most_interesting_errno;
 851         return -1;
 852 }
 853
 854 /*
 855  * Map the loose object at "path" if it is not NULL, or the path found by
 856  * searching for a loose object named "sha1".
 857  */
 858 static void *map_sha1_file_1(const char *path,
 859                              const unsigned char *sha1,
 860                              unsigned long *size)
 861 {
 862         void *map;
 863         int fd;
 864
 865         if (path)
 866                 fd = git_open(path);
 867         else
 868                 fd = open_sha1_file(sha1, &path);
 869         map = NULL;
 870         if (fd >= 0) {
 871                 struct stat st;
 872
 873                 if (!fstat(fd, &st)) {
 874                         *size = xsize_t(st.st_size);
 875                         if (!*size) {
 876                                 /* mmap() is forbidden on empty files */
 877                                 error("object file %s is empty", path);
 878                                 return NULL;
 879                         }
 880                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 881                 }
 882                 close(fd);
 883         }
 884         return map;
 885 }
 886
 887 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 888 {
 889         return map_sha1_file_1(NULL, sha1, size);
 890 }
 891
 892 static int unpack_sha1_short_header(git_zstream *stream,
 893                                     unsigned char *map, unsigned long mapsize,
 894                                     void *buffer, unsigned long bufsiz)
 895 {
 896         /* Get the data stream */
 897         memset(stream, 0, sizeof(*stream));
 898         stream->next_in = map;
 899         stream->avail_in = mapsize;
 900         stream->next_out = buffer;
 901         stream->avail_out = bufsiz;
 902
 903         git_inflate_init(stream);
 904         return git_inflate(stream, 0);
 905 }
 906
 907 int unpack_sha1_header(git_zstream *stream,
 908                        unsigned char *map, unsigned long mapsize,
 909                        void *buffer, unsigned long bufsiz)
 910 {
 911         int status = unpack_sha1_short_header(stream, map, mapsize,
 912                                               buffer, bufsiz);
 913
 914         if (status < Z_OK)
 915                 return status;
 916
 917         /* Make sure we have the terminating NUL */
 918         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 919                 return -1;
 920         return 0;
 921 }
 922
 923 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 924                                         unsigned long mapsize, void *buffer,
 925                                         unsigned long bufsiz, struct strbuf *header)
 926 {
 927         int status;
 928
 929         status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 930         if (status < Z_OK)
 931                 return -1;
 932
 933         /*
 934          * Check if entire header is unpacked in the first iteration.
 935          */
 936         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 937                 return 0;
 938
 939         /*
 940          * buffer[0..bufsiz] was not large enough.  Copy the partial
 941          * result out to header, and then append the result of further
 942          * reading the stream.
 943          */
 944         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 945         stream->next_out = buffer;
 946         stream->avail_out = bufsiz;
 947
 948         do {
 949                 status = git_inflate(stream, 0);
 950                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 951                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 952                         return 0;
 953                 stream->next_out = buffer;
 954                 stream->avail_out = bufsiz;
 955         } while (status != Z_STREAM_END);
 956         return -1;
 957 }
 958
 959 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 960 {
 961         int bytes = strlen(buffer) + 1;
 962         unsigned char *buf = xmallocz(size);
 963         unsigned long n;
 964         int status = Z_OK;
 965
 966         n = stream->total_out - bytes;
 967         if (n > size)
 968                 n = size;
 969         memcpy(buf, (char *) buffer + bytes, n);
 970         bytes = n;
 971         if (bytes <= size) {
 972                 /*
 973                  * The above condition must be (bytes <= size), not
 974                  * (bytes < size).  In other words, even though we
 975                  * expect no more output and set avail_out to zero,
 976                  * the input zlib stream may have bytes that express
 977                  * "this concludes the stream", and we *do* want to
 978                  * eat that input.
 979                  *
 980                  * Otherwise we would not be able to test that we
 981                  * consumed all the input to reach the expected size;
 982                  * we also want to check that zlib tells us that all
 983                  * went well with status == Z_STREAM_END at the end.
 984                  */
 985                 stream->next_out = buf + bytes;
 986                 stream->avail_out = size - bytes;
 987                 while (status == Z_OK)
 988                         status = git_inflate(stream, Z_FINISH);
 989         }
 990         if (status == Z_STREAM_END && !stream->avail_in) {
 991                 git_inflate_end(stream);
 992                 return buf;
 993         }
 994
 995         if (status < 0)
 996                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
 997         else if (stream->avail_in)
 998                 error("garbage at end of loose object '%s'",
 999                       sha1_to_hex(sha1));
1000         free(buf);
1001         return NULL;
1002 }
1003
1004 /*
1005  * We used to just use "sscanf()", but that's actually way
1006  * too permissive for what we want to check. So do an anal
1007  * object header parse by hand.
1008  */
1009 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1010                                unsigned int flags)
1011 {
1012         const char *type_buf = hdr;
1013         unsigned long size;
1014         int type, type_len = 0;
1015
1016         /*
1017          * The type can be of any size but is followed by
1018          * a space.
1019          */
1020         for (;;) {
1021                 char c = *hdr++;
1022                 if (!c)
1023                         return -1;
1024                 if (c == ' ')
1025                         break;
1026                 type_len++;
1027         }
1028
1029         type = type_from_string_gently(type_buf, type_len, 1);
1030         if (oi->typename)
1031                 strbuf_add(oi->typename, type_buf, type_len);
1032         /*
1033          * Set type to 0 if its an unknown object and
1034          * we're obtaining the type using '--allow-unknown-type'
1035          * option.
1036          */
1037         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1038                 type = 0;
1039         else if (type < 0)
1040                 die("invalid object type");
1041         if (oi->typep)
1042                 *oi->typep = type;
1043
1044         /*
1045          * The length must follow immediately, and be in canonical
1046          * decimal format (ie "010" is not valid).
1047          */
1048         size = *hdr++ - '0';
1049         if (size > 9)
1050                 return -1;
1051         if (size) {
1052                 for (;;) {
1053                         unsigned long c = *hdr - '0';
1054                         if (c > 9)
1055                                 break;
1056                         hdr++;
1057                         size = size * 10 + c;
1058                 }
1059         }
1060
1061         if (oi->sizep)
1062                 *oi->sizep = size;
1063
1064         /*
1065          * The length must be followed by a zero byte
1066          */
1067         return *hdr ? -1 : type;
1068 }
1069
1070 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1071 {
1072         struct object_info oi = OBJECT_INFO_INIT;
1073
1074         oi.sizep = sizep;
1075         return parse_sha1_header_extended(hdr, &oi, 0);
1076 }
1077
1078 off_t find_pack_entry_one(const unsigned char *sha1,
1079                                   struct packed_git *p)
1080 {
1081         const uint32_t *level1_ofs = p->index_data;
1082         const unsigned char *index = p->index_data;
1083         unsigned hi, lo, stride;
1084         static int debug_lookup = -1;
1085
1086         if (debug_lookup < 0)
1087                 debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
1088
1089         if (!index) {
1090                 if (open_pack_index(p))
1091                         return 0;
1092                 level1_ofs = p->index_data;
1093                 index = p->index_data;
1094         }
1095         if (p->index_version > 1) {
1096                 level1_ofs += 2;
1097                 index += 8;
1098         }
1099         index += 4 * 256;
1100         hi = ntohl(level1_ofs[*sha1]);
1101         lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
1102         if (p->index_version > 1) {
1103                 stride = 20;
1104         } else {
1105                 stride = 24;
1106                 index += 4;
1107         }
1108
1109         if (debug_lookup)
1110                 printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
1111                        sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
1112
1113         while (lo < hi) {
1114                 unsigned mi = (lo + hi) / 2;
1115                 int cmp = hashcmp(index + mi * stride, sha1);
1116
1117                 if (debug_lookup)
1118                         printf("lo %u hi %u rg %u mi %u\n",
1119                                lo, hi, hi - lo, mi);
1120                 if (!cmp)
1121                         return nth_packed_object_offset(p, mi);
1122                 if (cmp > 0)
1123                         hi = mi;
1124                 else
1125                         lo = mi+1;
1126         }
1127         return 0;
1128 }
1129
1130 int is_pack_valid(struct packed_git *p)
1131 {
1132         /* An already open pack is known to be valid. */
1133         if (p->pack_fd != -1)
1134                 return 1;
1135
1136         /* If the pack has one window completely covering the
1137          * file size, the pack is known to be valid even if
1138          * the descriptor is not currently open.
1139          */
1140         if (p->windows) {
1141                 struct pack_window *w = p->windows;
1142
1143                 if (!w->offset && w->len == p->pack_size)
1144                         return 1;
1145         }
1146
1147         /* Force the pack to open to prove its valid. */
1148         return !open_packed_git(p);
1149 }
1150
1151 static int fill_pack_entry(const unsigned char *sha1,
1152                            struct pack_entry *e,
1153                            struct packed_git *p)
1154 {
1155         off_t offset;
1156
1157         if (p->num_bad_objects) {
1158                 unsigned i;
1159                 for (i = 0; i < p->num_bad_objects; i++)
1160                         if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1161                                 return 0;
1162         }
1163
1164         offset = find_pack_entry_one(sha1, p);
1165         if (!offset)
1166                 return 0;
1167
1168         /*
1169          * We are about to tell the caller where they can locate the
1170          * requested object.  We better make sure the packfile is
1171          * still here and can be accessed before supplying that
1172          * answer, as it may have been deleted since the index was
1173          * loaded!
1174          */
1175         if (!is_pack_valid(p))
1176                 return 0;
1177         e->offset = offset;
1178         e->p = p;
1179         hashcpy(e->sha1, sha1);
1180         return 1;
1181 }
1182
1183 /*
1184  * Iff a pack file contains the object named by sha1, return true and
1185  * store its location to e.
1186  */
1187 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1188 {
1189         struct mru_entry *p;
1190
1191         prepare_packed_git();
1192         if (!packed_git)
1193                 return 0;
1194
1195         for (p = packed_git_mru->head; p; p = p->next) {
1196                 if (fill_pack_entry(sha1, e, p->item)) {
1197                         mru_mark(packed_git_mru, p);
1198                         return 1;
1199                 }
1200         }
1201         return 0;
1202 }
1203
1204 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1205                                   struct packed_git *packs)
1206 {
1207         struct packed_git *p;
1208
1209         for (p = packs; p; p = p->next) {
1210                 if (find_pack_entry_one(sha1, p))
1211                         return p;
1212         }
1213         return NULL;
1214
1215 }
1216
1217 static int sha1_loose_object_info(const unsigned char *sha1,
1218                                   struct object_info *oi,
1219                                   int flags)
1220 {
1221         int status = 0;
1222         unsigned long mapsize;
1223         void *map;
1224         git_zstream stream;
1225         char hdr[32];
1226         struct strbuf hdrbuf = STRBUF_INIT;
1227         unsigned long size_scratch;
1228
1229         if (oi->delta_base_sha1)
1230                 hashclr(oi->delta_base_sha1);
1231
1232         /*
1233          * If we don't care about type or size, then we don't
1234          * need to look inside the object at all. Note that we
1235          * do not optimize out the stat call, even if the
1236          * caller doesn't care about the disk-size, since our
1237          * return value implicitly indicates whether the
1238          * object even exists.
1239          */
1240         if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1241                 const char *path;
1242                 struct stat st;
1243                 if (stat_sha1_file(sha1, &st, &path) < 0)
1244                         return -1;
1245                 if (oi->disk_sizep)
1246                         *oi->disk_sizep = st.st_size;
1247                 return 0;
1248         }
1249
1250         map = map_sha1_file(sha1, &mapsize);
1251         if (!map)
1252                 return -1;
1253
1254         if (!oi->sizep)
1255                 oi->sizep = &size_scratch;
1256
1257         if (oi->disk_sizep)
1258                 *oi->disk_sizep = mapsize;
1259         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1260                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1261                         status = error("unable to unpack %s header with --allow-unknown-type",
1262                                        sha1_to_hex(sha1));
1263         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1264                 status = error("unable to unpack %s header",
1265                                sha1_to_hex(sha1));
1266         if (status < 0)
1267                 ; /* Do nothing */
1268         else if (hdrbuf.len) {
1269                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1270                         status = error("unable to parse %s header with --allow-unknown-type",
1271                                        sha1_to_hex(sha1));
1272         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1273                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1274
1275         if (status >= 0 && oi->contentp)
1276                 *oi->contentp = unpack_sha1_rest(&stream, hdr,
1277                                                  *oi->sizep, sha1);
1278         else
1279                 git_inflate_end(&stream);
1280
1281         munmap(map, mapsize);
1282         if (status && oi->typep)
1283                 *oi->typep = status;
1284         if (oi->sizep == &size_scratch)
1285                 oi->sizep = NULL;
1286         strbuf_release(&hdrbuf);
1287         oi->whence = OI_LOOSE;
1288         return (status < 0) ? status : 0;
1289 }
1290
1291 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1292 {
1293         static struct object_info blank_oi = OBJECT_INFO_INIT;
1294         struct pack_entry e;
1295         int rtype;
1296         const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1297                                     lookup_replace_object(sha1) :
1298                                     sha1;
1299
1300         if (!oi)
1301                 oi = &blank_oi;
1302
1303         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1304                 struct cached_object *co = find_cached_object(real);
1305                 if (co) {
1306                         if (oi->typep)
1307                                 *(oi->typep) = co->type;
1308                         if (oi->sizep)
1309                                 *(oi->sizep) = co->size;
1310                         if (oi->disk_sizep)
1311                                 *(oi->disk_sizep) = 0;
1312                         if (oi->delta_base_sha1)
1313                                 hashclr(oi->delta_base_sha1);
1314                         if (oi->typename)
1315                                 strbuf_addstr(oi->typename, typename(co->type));
1316                         if (oi->contentp)
1317                                 *oi->contentp = xmemdupz(co->buf, co->size);
1318                         oi->whence = OI_CACHED;
1319                         return 0;
1320                 }
1321         }
1322
1323         if (!find_pack_entry(real, &e)) {
1324                 /* Most likely it's a loose object. */
1325                 if (!sha1_loose_object_info(real, oi, flags))
1326                         return 0;
1327
1328                 /* Not a loose object; someone else may have just packed it. */
1329                 if (flags & OBJECT_INFO_QUICK) {
1330                         return -1;
1331                 } else {
1332                         reprepare_packed_git();
1333                         if (!find_pack_entry(real, &e))
1334                                 return -1;
1335                 }
1336         }
1337
1338         if (oi == &blank_oi)
1339                 /*
1340                  * We know that the caller doesn't actually need the
1341                  * information below, so return early.
1342                  */
1343                 return 0;
1344
1345         rtype = packed_object_info(e.p, e.offset, oi);
1346         if (rtype < 0) {
1347                 mark_bad_packed_object(e.p, real);
1348                 return sha1_object_info_extended(real, oi, 0);
1349         } else if (oi->whence == OI_PACKED) {
1350                 oi->u.packed.offset = e.offset;
1351                 oi->u.packed.pack = e.p;
1352                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1353                                          rtype == OBJ_OFS_DELTA);
1354         }
1355
1356         return 0;
1357 }
1358
1359 /* returns enum object_type or negative */
1360 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1361 {
1362         enum object_type type;
1363         struct object_info oi = OBJECT_INFO_INIT;
1364
1365         oi.typep = &type;
1366         oi.sizep = sizep;
1367         if (sha1_object_info_extended(sha1, &oi,
1368                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1369                 return -1;
1370         return type;
1371 }
1372
1373 static void *read_object(const unsigned char *sha1, enum object_type *type,
1374                          unsigned long *size)
1375 {
1376         struct object_info oi = OBJECT_INFO_INIT;
1377         void *content;
1378         oi.typep = type;
1379         oi.sizep = size;
1380         oi.contentp = &content;
1381
1382         if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1383                 return NULL;
1384         return content;
1385 }
1386
1387 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1388                       unsigned char *sha1)
1389 {
1390         struct cached_object *co;
1391
1392         hash_sha1_file(buf, len, typename(type), sha1);
1393         if (has_sha1_file(sha1) || find_cached_object(sha1))
1394                 return 0;
1395         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1396         co = &cached_objects[cached_object_nr++];
1397         co->size = len;
1398         co->type = type;
1399         co->buf = xmalloc(len);
1400         memcpy(co->buf, buf, len);
1401         hashcpy(co->sha1, sha1);
1402         return 0;
1403 }
1404
1405 /*
1406  * This function dies on corrupt objects; the callers who want to
1407  * deal with them should arrange to call read_object() and give error
1408  * messages themselves.
1409  */
1410 void *read_sha1_file_extended(const unsigned char *sha1,
1411                               enum object_type *type,
1412                               unsigned long *size,
1413                               int lookup_replace)
1414 {
1415         void *data;
1416         const struct packed_git *p;
1417         const char *path;
1418         struct stat st;
1419         const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1420                                                    : sha1;
1421
1422         errno = 0;
1423         data = read_object(repl, type, size);
1424         if (data)
1425                 return data;
1426
1427         if (errno && errno != ENOENT)
1428                 die_errno("failed to read object %s", sha1_to_hex(sha1));
1429
1430         /* die if we replaced an object with one that does not exist */
1431         if (repl != sha1)
1432                 die("replacement %s not found for %s",
1433                     sha1_to_hex(repl), sha1_to_hex(sha1));
1434
1435         if (!stat_sha1_file(repl, &st, &path))
1436                 die("loose object %s (stored in %s) is corrupt",
1437                     sha1_to_hex(repl), path);
1438
1439         if ((p = has_packed_and_bad(repl)) != NULL)
1440                 die("packed object %s (stored in %s) is corrupt",
1441                     sha1_to_hex(repl), p->pack_name);
1442
1443         return NULL;
1444 }
1445
1446 void *read_object_with_reference(const unsigned char *sha1,
1447                                  const char *required_type_name,
1448                                  unsigned long *size,
1449                                  unsigned char *actual_sha1_return)
1450 {
1451         enum object_type type, required_type;
1452         void *buffer;
1453         unsigned long isize;
1454         unsigned char actual_sha1[20];
1455
1456         required_type = type_from_string(required_type_name);
1457         hashcpy(actual_sha1, sha1);
1458         while (1) {
1459                 int ref_length = -1;
1460                 const char *ref_type = NULL;
1461
1462                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1463                 if (!buffer)
1464                         return NULL;
1465                 if (type == required_type) {
1466                         *size = isize;
1467                         if (actual_sha1_return)
1468                                 hashcpy(actual_sha1_return, actual_sha1);
1469                         return buffer;
1470                 }
1471                 /* Handle references */
1472                 else if (type == OBJ_COMMIT)
1473                         ref_type = "tree ";
1474                 else if (type == OBJ_TAG)
1475                         ref_type = "object ";
1476                 else {
1477                         free(buffer);
1478                         return NULL;
1479                 }
1480                 ref_length = strlen(ref_type);
1481
1482                 if (ref_length + 40 > isize ||
1483                     memcmp(buffer, ref_type, ref_length) ||
1484                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1485                         free(buffer);
1486                         return NULL;
1487                 }
1488                 free(buffer);
1489                 /* Now we have the ID of the referred-to object in
1490                  * actual_sha1.  Check again. */
1491         }
1492 }
1493
1494 static void write_sha1_file_prepare(const void *buf, unsigned long len,
1495                                     const char *type, unsigned char *sha1,
1496                                     char *hdr, int *hdrlen)
1497 {
1498         git_SHA_CTX c;
1499
1500         /* Generate the header */
1501         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1502
1503         /* Sha1.. */
1504         git_SHA1_Init(&c);
1505         git_SHA1_Update(&c, hdr, *hdrlen);
1506         git_SHA1_Update(&c, buf, len);
1507         git_SHA1_Final(sha1, &c);
1508 }
1509
1510 /*
1511  * Move the just written object into its final resting place.
1512  */
1513 int finalize_object_file(const char *tmpfile, const char *filename)
1514 {
1515         int ret = 0;
1516
1517         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1518                 goto try_rename;
1519         else if (link(tmpfile, filename))
1520                 ret = errno;
1521
1522         /*
1523          * Coda hack - coda doesn't like cross-directory links,
1524          * so we fall back to a rename, which will mean that it
1525          * won't be able to check collisions, but that's not a
1526          * big deal.
1527          *
1528          * The same holds for FAT formatted media.
1529          *
1530          * When this succeeds, we just return.  We have nothing
1531          * left to unlink.
1532          */
1533         if (ret && ret != EEXIST) {
1534         try_rename:
1535                 if (!rename(tmpfile, filename))
1536                         goto out;
1537                 ret = errno;
1538         }
1539         unlink_or_warn(tmpfile);
1540         if (ret) {
1541                 if (ret != EEXIST) {
1542                         return error_errno("unable to write sha1 filename %s", filename);
1543                 }
1544                 /* FIXME!!! Collision check here ? */
1545         }
1546
1547 out:
1548         if (adjust_shared_perm(filename))
1549                 return error("unable to set permission to '%s'", filename);
1550         return 0;
1551 }
1552
1553 static int write_buffer(int fd, const void *buf, size_t len)
1554 {
1555         if (write_in_full(fd, buf, len) < 0)
1556                 return error_errno("file write error");
1557         return 0;
1558 }
1559
1560 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1561                    unsigned char *sha1)
1562 {
1563         char hdr[32];
1564         int hdrlen = sizeof(hdr);
1565         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1566         return 0;
1567 }
1568
1569 /* Finalize a file on disk, and close it. */
1570 static void close_sha1_file(int fd)
1571 {
1572         if (fsync_object_files)
1573                 fsync_or_die(fd, "sha1 file");
1574         if (close(fd) != 0)
1575                 die_errno("error when closing sha1 file");
1576 }
1577
1578 /* Size of directory component, including the ending '/' */
1579 static inline int directory_size(const char *filename)
1580 {
1581         const char *s = strrchr(filename, '/');
1582         if (!s)
1583                 return 0;
1584         return s - filename + 1;
1585 }
1586
1587 /*
1588  * This creates a temporary file in the same directory as the final
1589  * 'filename'
1590  *
1591  * We want to avoid cross-directory filename renames, because those
1592  * can have problems on various filesystems (FAT, NFS, Coda).
1593  */
1594 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1595 {
1596         int fd, dirlen = directory_size(filename);
1597
1598         strbuf_reset(tmp);
1599         strbuf_add(tmp, filename, dirlen);
1600         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1601         fd = git_mkstemp_mode(tmp->buf, 0444);
1602         if (fd < 0 && dirlen && errno == ENOENT) {
1603                 /*
1604                  * Make sure the directory exists; note that the contents
1605                  * of the buffer are undefined after mkstemp returns an
1606                  * error, so we have to rewrite the whole buffer from
1607                  * scratch.
1608                  */
1609                 strbuf_reset(tmp);
1610                 strbuf_add(tmp, filename, dirlen - 1);
1611                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1612                         return -1;
1613                 if (adjust_shared_perm(tmp->buf))
1614                         return -1;
1615
1616                 /* Try again */
1617                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1618                 fd = git_mkstemp_mode(tmp->buf, 0444);
1619         }
1620         return fd;
1621 }
1622
1623 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1624                               const void *buf, unsigned long len, time_t mtime)
1625 {
1626         int fd, ret;
1627         unsigned char compressed[4096];
1628         git_zstream stream;
1629         git_SHA_CTX c;
1630         unsigned char parano_sha1[20];
1631         static struct strbuf tmp_file = STRBUF_INIT;
1632         const char *filename = sha1_file_name(sha1);
1633
1634         fd = create_tmpfile(&tmp_file, filename);
1635         if (fd < 0) {
1636                 if (errno == EACCES)
1637                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1638                 else
1639                         return error_errno("unable to create temporary file");
1640         }
1641
1642         /* Set it up */
1643         git_deflate_init(&stream, zlib_compression_level);
1644         stream.next_out = compressed;
1645         stream.avail_out = sizeof(compressed);
1646         git_SHA1_Init(&c);
1647
1648         /* First header.. */
1649         stream.next_in = (unsigned char *)hdr;
1650         stream.avail_in = hdrlen;
1651         while (git_deflate(&stream, 0) == Z_OK)
1652                 ; /* nothing */
1653         git_SHA1_Update(&c, hdr, hdrlen);
1654
1655         /* Then the data itself.. */
1656         stream.next_in = (void *)buf;
1657         stream.avail_in = len;
1658         do {
1659                 unsigned char *in0 = stream.next_in;
1660                 ret = git_deflate(&stream, Z_FINISH);
1661                 git_SHA1_Update(&c, in0, stream.next_in - in0);
1662                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1663                         die("unable to write sha1 file");
1664                 stream.next_out = compressed;
1665                 stream.avail_out = sizeof(compressed);
1666         } while (ret == Z_OK);
1667
1668         if (ret != Z_STREAM_END)
1669                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1670         ret = git_deflate_end_gently(&stream);
1671         if (ret != Z_OK)
1672                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1673         git_SHA1_Final(parano_sha1, &c);
1674         if (hashcmp(sha1, parano_sha1) != 0)
1675                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1676
1677         close_sha1_file(fd);
1678
1679         if (mtime) {
1680                 struct utimbuf utb;
1681                 utb.actime = mtime;
1682                 utb.modtime = mtime;
1683                 if (utime(tmp_file.buf, &utb) < 0)
1684                         warning_errno("failed utime() on %s", tmp_file.buf);
1685         }
1686
1687         return finalize_object_file(tmp_file.buf, filename);
1688 }
1689
1690 static int freshen_loose_object(const unsigned char *sha1)
1691 {
1692         return check_and_freshen(sha1, 1);
1693 }
1694
1695 static int freshen_packed_object(const unsigned char *sha1)
1696 {
1697         struct pack_entry e;
1698         if (!find_pack_entry(sha1, &e))
1699                 return 0;
1700         if (e.p->freshened)
1701                 return 1;
1702         if (!freshen_file(e.p->pack_name))
1703                 return 0;
1704         e.p->freshened = 1;
1705         return 1;
1706 }
1707
1708 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1709 {
1710         char hdr[32];
1711         int hdrlen = sizeof(hdr);
1712
1713         /* Normally if we have it in the pack then we do not bother writing
1714          * it out into .git/objects/??/?{38} file.
1715          */
1716         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1717         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1718                 return 0;
1719         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1720 }
1721
1722 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1723                              unsigned char *sha1, unsigned flags)
1724 {
1725         char *header;
1726         int hdrlen, status = 0;
1727
1728         /* type string, SP, %lu of the length plus NUL must fit this */
1729         hdrlen = strlen(type) + 32;
1730         header = xmalloc(hdrlen);
1731         write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
1732
1733         if (!(flags & HASH_WRITE_OBJECT))
1734                 goto cleanup;
1735         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1736                 goto cleanup;
1737         status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
1738
1739 cleanup:
1740         free(header);
1741         return status;
1742 }
1743
1744 int force_object_loose(const unsigned char *sha1, time_t mtime)
1745 {
1746         void *buf;
1747         unsigned long len;
1748         enum object_type type;
1749         char hdr[32];
1750         int hdrlen;
1751         int ret;
1752
1753         if (has_loose_object(sha1))
1754                 return 0;
1755         buf = read_object(sha1, &type, &len);
1756         if (!buf)
1757                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1758         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1759         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1760         free(buf);
1761
1762         return ret;
1763 }
1764
1765 int has_pack_index(const unsigned char *sha1)
1766 {
1767         struct stat st;
1768         if (stat(sha1_pack_index_name(sha1), &st))
1769                 return 0;
1770         return 1;
1771 }
1772
1773 int has_sha1_pack(const unsigned char *sha1)
1774 {
1775         struct pack_entry e;
1776         return find_pack_entry(sha1, &e);
1777 }
1778
1779 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1780 {
1781         if (!startup_info->have_repository)
1782                 return 0;
1783         return sha1_object_info_extended(sha1, NULL,
1784                                          flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1785 }
1786
1787 int has_object_file(const struct object_id *oid)
1788 {
1789         return has_sha1_file(oid->hash);
1790 }
1791
1792 int has_object_file_with_flags(const struct object_id *oid, int flags)
1793 {
1794         return has_sha1_file_with_flags(oid->hash, flags);
1795 }
1796
1797 static void check_tree(const void *buf, size_t size)
1798 {
1799         struct tree_desc desc;
1800         struct name_entry entry;
1801
1802         init_tree_desc(&desc, buf, size);
1803         while (tree_entry(&desc, &entry))
1804                 /* do nothing
1805                  * tree_entry() will die() on malformed entries */
1806                 ;
1807 }
1808
1809 static void check_commit(const void *buf, size_t size)
1810 {
1811         struct commit c;
1812         memset(&c, 0, sizeof(c));
1813         if (parse_commit_buffer(&c, buf, size))
1814                 die("corrupt commit");
1815 }
1816
1817 static void check_tag(const void *buf, size_t size)
1818 {
1819         struct tag t;
1820         memset(&t, 0, sizeof(t));
1821         if (parse_tag_buffer(&t, buf, size))
1822                 die("corrupt tag");
1823 }
1824
1825 static int index_mem(unsigned char *sha1, void *buf, size_t size,
1826                      enum object_type type,
1827                      const char *path, unsigned flags)
1828 {
1829         int ret, re_allocated = 0;
1830         int write_object = flags & HASH_WRITE_OBJECT;
1831
1832         if (!type)
1833                 type = OBJ_BLOB;
1834
1835         /*
1836          * Convert blobs to git internal format
1837          */
1838         if ((type == OBJ_BLOB) && path) {
1839                 struct strbuf nbuf = STRBUF_INIT;
1840                 if (convert_to_git(&the_index, path, buf, size, &nbuf,
1841                                    write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
1842                         buf = strbuf_detach(&nbuf, &size);
1843                         re_allocated = 1;
1844                 }
1845         }
1846         if (flags & HASH_FORMAT_CHECK) {
1847                 if (type == OBJ_TREE)
1848                         check_tree(buf, size);
1849                 if (type == OBJ_COMMIT)
1850                         check_commit(buf, size);
1851                 if (type == OBJ_TAG)
1852                         check_tag(buf, size);
1853         }
1854
1855         if (write_object)
1856                 ret = write_sha1_file(buf, size, typename(type), sha1);
1857         else
1858                 ret = hash_sha1_file(buf, size, typename(type), sha1);
1859         if (re_allocated)
1860                 free(buf);
1861         return ret;
1862 }
1863
1864 static int index_stream_convert_blob(unsigned char *sha1, int fd,
1865                                      const char *path, unsigned flags)
1866 {
1867         int ret;
1868         const int write_object = flags & HASH_WRITE_OBJECT;
1869         struct strbuf sbuf = STRBUF_INIT;
1870
1871         assert(path);
1872         assert(would_convert_to_git_filter_fd(path));
1873
1874         convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1875                                  write_object ? safe_crlf : SAFE_CRLF_FALSE);
1876
1877         if (write_object)
1878                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1879                                       sha1);
1880         else
1881                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1882                                      sha1);
1883         strbuf_release(&sbuf);
1884         return ret;
1885 }
1886
1887 static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
1888                       const char *path, unsigned flags)
1889 {
1890         struct strbuf sbuf = STRBUF_INIT;
1891         int ret;
1892
1893         if (strbuf_read(&sbuf, fd, 4096) >= 0)
1894                 ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
1895         else
1896                 ret = -1;
1897         strbuf_release(&sbuf);
1898         return ret;
1899 }
1900
1901 #define SMALL_FILE_SIZE (32*1024)
1902
1903 static int index_core(unsigned char *sha1, int fd, size_t size,
1904                       enum object_type type, const char *path,
1905                       unsigned flags)
1906 {
1907         int ret;
1908
1909         if (!size) {
1910                 ret = index_mem(sha1, "", size, type, path, flags);
1911         } else if (size <= SMALL_FILE_SIZE) {
1912                 char *buf = xmalloc(size);
1913                 if (size == read_in_full(fd, buf, size))
1914                         ret = index_mem(sha1, buf, size, type, path, flags);
1915                 else
1916                         ret = error_errno("short read");
1917                 free(buf);
1918         } else {
1919                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1920                 ret = index_mem(sha1, buf, size, type, path, flags);
1921                 munmap(buf, size);
1922         }
1923         return ret;
1924 }
1925
1926 /*
1927  * This creates one packfile per large blob unless bulk-checkin
1928  * machinery is "plugged".
1929  *
1930  * This also bypasses the usual "convert-to-git" dance, and that is on
1931  * purpose. We could write a streaming version of the converting
1932  * functions and insert that before feeding the data to fast-import
1933  * (or equivalent in-core API described above). However, that is
1934  * somewhat complicated, as we do not know the size of the filter
1935  * result, which we need to know beforehand when writing a git object.
1936  * Since the primary motivation for trying to stream from the working
1937  * tree file and to avoid mmaping it in core is to deal with large
1938  * binary blobs, they generally do not want to get any conversion, and
1939  * callers should avoid this code path when filters are requested.
1940  */
1941 static int index_stream(unsigned char *sha1, int fd, size_t size,
1942                         enum object_type type, const char *path,
1943                         unsigned flags)
1944 {
1945         return index_bulk_checkin(sha1, fd, size, type, path, flags);
1946 }
1947
1948 int index_fd(unsigned char *sha1, int fd, struct stat *st,
1949              enum object_type type, const char *path, unsigned flags)
1950 {
1951         int ret;
1952
1953         /*
1954          * Call xsize_t() only when needed to avoid potentially unnecessary
1955          * die() for large files.
1956          */
1957         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1958                 ret = index_stream_convert_blob(sha1, fd, path, flags);
1959         else if (!S_ISREG(st->st_mode))
1960                 ret = index_pipe(sha1, fd, type, path, flags);
1961         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1962                  (path && would_convert_to_git(&the_index, path)))
1963                 ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
1964                                  flags);
1965         else
1966                 ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
1967                                    flags);
1968         close(fd);
1969         return ret;
1970 }
1971
1972 int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
1973 {
1974         int fd;
1975         struct strbuf sb = STRBUF_INIT;
1976
1977         switch (st->st_mode & S_IFMT) {
1978         case S_IFREG:
1979                 fd = open(path, O_RDONLY);
1980                 if (fd < 0)
1981                         return error_errno("open(\"%s\")", path);
1982                 if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
1983                         return error("%s: failed to insert into database",
1984                                      path);
1985                 break;
1986         case S_IFLNK:
1987                 if (strbuf_readlink(&sb, path, st->st_size))
1988                         return error_errno("readlink(\"%s\")", path);
1989                 if (!(flags & HASH_WRITE_OBJECT))
1990                         hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
1991                 else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
1992                         return error("%s: failed to insert into database",
1993                                      path);
1994                 strbuf_release(&sb);
1995                 break;
1996         case S_IFDIR:
1997                 return resolve_gitlink_ref(path, "HEAD", sha1);
1998         default:
1999                 return error("%s: unsupported file type", path);
2000         }
2001         return 0;
2002 }
2003
2004 int read_pack_header(int fd, struct pack_header *header)
2005 {
2006         if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
2007                 /* "eof before pack header was fully read" */
2008                 return PH_ERROR_EOF;
2009
2010         if (header->hdr_signature != htonl(PACK_SIGNATURE))
2011                 /* "protocol error (pack signature mismatch detected)" */
2012                 return PH_ERROR_PACK_SIGNATURE;
2013         if (!pack_version_ok(header->hdr_version))
2014                 /* "protocol error (pack version unsupported)" */
2015                 return PH_ERROR_PROTOCOL;
2016         return 0;
2017 }
2018
2019 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
2020 {
2021         enum object_type type = sha1_object_info(sha1, NULL);
2022         if (type < 0)
2023                 die("%s is not a valid object", sha1_to_hex(sha1));
2024         if (type != expect)
2025                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
2026                     typename(expect));
2027 }
2028
2029 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
2030                                 struct strbuf *path,
2031                                 each_loose_object_fn obj_cb,
2032                                 each_loose_cruft_fn cruft_cb,
2033                                 each_loose_subdir_fn subdir_cb,
2034                                 void *data)
2035 {
2036         size_t origlen, baselen;
2037         DIR *dir;
2038         struct dirent *de;
2039         int r = 0;
2040
2041         if (subdir_nr > 0xff)
2042                 BUG("invalid loose object subdirectory: %x", subdir_nr);
2043
2044         origlen = path->len;
2045         strbuf_complete(path, '/');
2046         strbuf_addf(path, "%02x", subdir_nr);
2047         baselen = path->len;
2048
2049         dir = opendir(path->buf);
2050         if (!dir) {
2051                 if (errno != ENOENT)
2052                         r = error_errno("unable to open %s", path->buf);
2053                 strbuf_setlen(path, origlen);
2054                 return r;
2055         }
2056
2057         while ((de = readdir(dir))) {
2058                 if (is_dot_or_dotdot(de->d_name))
2059                         continue;
2060
2061                 strbuf_setlen(path, baselen);
2062                 strbuf_addf(path, "/%s", de->d_name);
2063
2064                 if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
2065                         char hex[GIT_MAX_HEXSZ+1];
2066                         struct object_id oid;
2067
2068                         xsnprintf(hex, sizeof(hex), "%02x%s",
2069                                   subdir_nr, de->d_name);
2070                         if (!get_oid_hex(hex, &oid)) {
2071                                 if (obj_cb) {
2072                                         r = obj_cb(&oid, path->buf, data);
2073                                         if (r)
2074                                                 break;
2075                                 }
2076                                 continue;
2077                         }
2078                 }
2079
2080                 if (cruft_cb) {
2081                         r = cruft_cb(de->d_name, path->buf, data);
2082                         if (r)
2083                                 break;
2084                 }
2085         }
2086         closedir(dir);
2087
2088         strbuf_setlen(path, baselen);
2089         if (!r && subdir_cb)
2090                 r = subdir_cb(subdir_nr, path->buf, data);
2091
2092         strbuf_setlen(path, origlen);
2093
2094         return r;
2095 }
2096
2097 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2098                             each_loose_object_fn obj_cb,
2099                             each_loose_cruft_fn cruft_cb,
2100                             each_loose_subdir_fn subdir_cb,
2101                             void *data)
2102 {
2103         int r = 0;
2104         int i;
2105
2106         for (i = 0; i < 256; i++) {
2107                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2108                                                 subdir_cb, data);
2109                 if (r)
2110                         break;
2111         }
2112
2113         return r;
2114 }
2115
2116 int for_each_loose_file_in_objdir(const char *path,
2117                                   each_loose_object_fn obj_cb,
2118                                   each_loose_cruft_fn cruft_cb,
2119                                   each_loose_subdir_fn subdir_cb,
2120                                   void *data)
2121 {
2122         struct strbuf buf = STRBUF_INIT;
2123         int r;
2124
2125         strbuf_addstr(&buf, path);
2126         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2127                                               subdir_cb, data);
2128         strbuf_release(&buf);
2129
2130         return r;
2131 }
2132
2133 struct loose_alt_odb_data {
2134         each_loose_object_fn *cb;
2135         void *data;
2136 };
2137
2138 static int loose_from_alt_odb(struct alternate_object_database *alt,
2139                               void *vdata)
2140 {
2141         struct loose_alt_odb_data *data = vdata;
2142         struct strbuf buf = STRBUF_INIT;
2143         int r;
2144
2145         strbuf_addstr(&buf, alt->path);
2146         r = for_each_loose_file_in_objdir_buf(&buf,
2147                                               data->cb, NULL, NULL,
2148                                               data->data);
2149         strbuf_release(&buf);
2150         return r;
2151 }
2152
2153 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2154 {
2155         struct loose_alt_odb_data alt;
2156         int r;
2157
2158         r = for_each_loose_file_in_objdir(get_object_directory(),
2159                                           cb, NULL, NULL, data);
2160         if (r)
2161                 return r;
2162
2163         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2164                 return 0;
2165
2166         alt.cb = cb;
2167         alt.data = data;
2168         return foreach_alt_odb(loose_from_alt_odb, &alt);
2169 }
2170
2171 static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
2172 {
2173         uint32_t i;
2174         int r = 0;
2175
2176         for (i = 0; i < p->num_objects; i++) {
2177                 struct object_id oid;
2178
2179                 if (!nth_packed_object_oid(&oid, p, i))
2180                         return error("unable to get sha1 of object %u in %s",
2181                                      i, p->pack_name);
2182
2183                 r = cb(&oid, p, i, data);
2184                 if (r)
2185                         break;
2186         }
2187         return r;
2188 }
2189
2190 int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
2191 {
2192         struct packed_git *p;
2193         int r = 0;
2194         int pack_errors = 0;
2195
2196         prepare_packed_git();
2197         for (p = packed_git; p; p = p->next) {
2198                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2199                         continue;
2200                 if (open_pack_index(p)) {
2201                         pack_errors = 1;
2202                         continue;
2203                 }
2204                 r = for_each_object_in_pack(p, cb, data);
2205                 if (r)
2206                         break;
2207         }
2208         return r ? r : pack_errors;
2209 }
2210
2211 static int check_stream_sha1(git_zstream *stream,
2212                              const char *hdr,
2213                              unsigned long size,
2214                              const char *path,
2215                              const unsigned char *expected_sha1)
2216 {
2217         git_SHA_CTX c;
2218         unsigned char real_sha1[GIT_MAX_RAWSZ];
2219         unsigned char buf[4096];
2220         unsigned long total_read;
2221         int status = Z_OK;
2222
2223         git_SHA1_Init(&c);
2224         git_SHA1_Update(&c, hdr, stream->total_out);
2225
2226         /*
2227          * We already read some bytes into hdr, but the ones up to the NUL
2228          * do not count against the object's content size.
2229          */
2230         total_read = stream->total_out - strlen(hdr) - 1;
2231
2232         /*
2233          * This size comparison must be "<=" to read the final zlib packets;
2234          * see the comment in unpack_sha1_rest for details.
2235          */
2236         while (total_read <= size &&
2237                (status == Z_OK || status == Z_BUF_ERROR)) {
2238                 stream->next_out = buf;
2239                 stream->avail_out = sizeof(buf);
2240                 if (size - total_read < stream->avail_out)
2241                         stream->avail_out = size - total_read;
2242                 status = git_inflate(stream, Z_FINISH);
2243                 git_SHA1_Update(&c, buf, stream->next_out - buf);
2244                 total_read += stream->next_out - buf;
2245         }
2246         git_inflate_end(stream);
2247
2248         if (status != Z_STREAM_END) {
2249                 error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2250                 return -1;
2251         }
2252         if (stream->avail_in) {
2253                 error("garbage at end of loose object '%s'",
2254                       sha1_to_hex(expected_sha1));
2255                 return -1;
2256         }
2257
2258         git_SHA1_Final(real_sha1, &c);
2259         if (hashcmp(expected_sha1, real_sha1)) {
2260                 error("sha1 mismatch for %s (expected %s)", path,
2261                       sha1_to_hex(expected_sha1));
2262                 return -1;
2263         }
2264
2265         return 0;
2266 }
2267
2268 int read_loose_object(const char *path,
2269                       const unsigned char *expected_sha1,
2270                       enum object_type *type,
2271                       unsigned long *size,
2272                       void **contents)
2273 {
2274         int ret = -1;
2275         void *map = NULL;
2276         unsigned long mapsize;
2277         git_zstream stream;
2278         char hdr[32];
2279
2280         *contents = NULL;
2281
2282         map = map_sha1_file_1(path, NULL, &mapsize);
2283         if (!map) {
2284                 error_errno("unable to mmap %s", path);
2285                 goto out;
2286         }
2287
2288         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2289                 error("unable to unpack header of %s", path);
2290                 goto out;
2291         }
2292
2293         *type = parse_sha1_header(hdr, size);
2294         if (*type < 0) {
2295                 error("unable to parse header of %s", path);
2296                 git_inflate_end(&stream);
2297                 goto out;
2298         }
2299
2300         if (*type == OBJ_BLOB) {
2301                 if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2302                         goto out;
2303         } else {
2304                 *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2305                 if (!*contents) {
2306                         error("unable to unpack contents of %s", path);
2307                         git_inflate_end(&stream);
2308                         goto out;
2309                 }
2310                 if (check_sha1_signature(expected_sha1, *contents,
2311                                          *size, typename(*type))) {
2312                         error("sha1 mismatch for %s (expected %s)", path,
2313                               sha1_to_hex(expected_sha1));
2314                         free(*contents);
2315                         goto out;
2316                 }
2317         }
2318
2319         ret = 0; /* everything checks out */
2320
2321 out:
2322         if (map)
2323                 munmap(map, mapsize);
2324         return ret;
2325 }