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[GIT_MAX_RAWSZ];
  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
  78 static enum safe_crlf get_safe_crlf(unsigned flags)
  79 {
  80         if (flags & HASH_RENORMALIZE)
  81                 return SAFE_CRLF_RENORMALIZE;
  82         else if (flags & HASH_WRITE_OBJECT)
  83                 return safe_crlf;
  84         else
  85                 return SAFE_CRLF_FALSE;
  86 }
  87
  88
  89 int mkdir_in_gitdir(const char *path)
  90 {
  91         if (mkdir(path, 0777)) {
  92                 int saved_errno = errno;
  93                 struct stat st;
  94                 struct strbuf sb = STRBUF_INIT;
  95
  96                 if (errno != EEXIST)
  97                         return -1;
  98                 /*
  99                  * Are we looking at a path in a symlinked worktree
 100                  * whose original repository does not yet have it?
 101                  * e.g. .git/rr-cache pointing at its original
 102                  * repository in which the user hasn't performed any
 103                  * conflict resolution yet?
 104                  */
 105                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 106                     strbuf_readlink(&sb, path, st.st_size) ||
 107                     !is_absolute_path(sb.buf) ||
 108                     mkdir(sb.buf, 0777)) {
 109                         strbuf_release(&sb);
 110                         errno = saved_errno;
 111                         return -1;
 112                 }
 113                 strbuf_release(&sb);
 114         }
 115         return adjust_shared_perm(path);
 116 }
 117
 118 enum scld_error safe_create_leading_directories(char *path)
 119 {
 120         char *next_component = path + offset_1st_component(path);
 121         enum scld_error ret = SCLD_OK;
 122
 123         while (ret == SCLD_OK && next_component) {
 124                 struct stat st;
 125                 char *slash = next_component, slash_character;
 126
 127                 while (*slash && !is_dir_sep(*slash))
 128                         slash++;
 129
 130                 if (!*slash)
 131                         break;
 132
 133                 next_component = slash + 1;
 134                 while (is_dir_sep(*next_component))
 135                         next_component++;
 136                 if (!*next_component)
 137                         break;
 138
 139                 slash_character = *slash;
 140                 *slash = '\0';
 141                 if (!stat(path, &st)) {
 142                         /* path exists */
 143                         if (!S_ISDIR(st.st_mode)) {
 144                                 errno = ENOTDIR;
 145                                 ret = SCLD_EXISTS;
 146                         }
 147                 } else if (mkdir(path, 0777)) {
 148                         if (errno == EEXIST &&
 149                             !stat(path, &st) && S_ISDIR(st.st_mode))
 150                                 ; /* somebody created it since we checked */
 151                         else if (errno == ENOENT)
 152                                 /*
 153                                  * Either mkdir() failed because
 154                                  * somebody just pruned the containing
 155                                  * directory, or stat() failed because
 156                                  * the file that was in our way was
 157                                  * just removed.  Either way, inform
 158                                  * the caller that it might be worth
 159                                  * trying again:
 160                                  */
 161                                 ret = SCLD_VANISHED;
 162                         else
 163                                 ret = SCLD_FAILED;
 164                 } else if (adjust_shared_perm(path)) {
 165                         ret = SCLD_PERMS;
 166                 }
 167                 *slash = slash_character;
 168         }
 169         return ret;
 170 }
 171
 172 enum scld_error safe_create_leading_directories_const(const char *path)
 173 {
 174         int save_errno;
 175         /* path points to cache entries, so xstrdup before messing with it */
 176         char *buf = xstrdup(path);
 177         enum scld_error result = safe_create_leading_directories(buf);
 178
 179         save_errno = errno;
 180         free(buf);
 181         errno = save_errno;
 182         return result;
 183 }
 184
 185 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 186 {
 187         /*
 188          * The number of times we will try to remove empty directories
 189          * in the way of path. This is only 1 because if another
 190          * process is racily creating directories that conflict with
 191          * us, we don't want to fight against them.
 192          */
 193         int remove_directories_remaining = 1;
 194
 195         /*
 196          * The number of times that we will try to create the
 197          * directories containing path. We are willing to attempt this
 198          * more than once, because another process could be trying to
 199          * clean up empty directories at the same time as we are
 200          * trying to create them.
 201          */
 202         int create_directories_remaining = 3;
 203
 204         /* A scratch copy of path, filled lazily if we need it: */
 205         struct strbuf path_copy = STRBUF_INIT;
 206
 207         int ret, save_errno;
 208
 209         /* Sanity check: */
 210         assert(*path);
 211
 212 retry_fn:
 213         ret = fn(path, cb);
 214         save_errno = errno;
 215         if (!ret)
 216                 goto out;
 217
 218         if (errno == EISDIR && remove_directories_remaining-- > 0) {
 219                 /*
 220                  * A directory is in the way. Maybe it is empty; try
 221                  * to remove it:
 222                  */
 223                 if (!path_copy.len)
 224                         strbuf_addstr(&path_copy, path);
 225
 226                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 227                         goto retry_fn;
 228         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 229                 /*
 230                  * Maybe the containing directory didn't exist, or
 231                  * maybe it was just deleted by a process that is
 232                  * racing with us to clean up empty directories. Try
 233                  * to create it:
 234                  */
 235                 enum scld_error scld_result;
 236
 237                 if (!path_copy.len)
 238                         strbuf_addstr(&path_copy, path);
 239
 240                 do {
 241                         scld_result = safe_create_leading_directories(path_copy.buf);
 242                         if (scld_result == SCLD_OK)
 243                                 goto retry_fn;
 244                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 245         }
 246
 247 out:
 248         strbuf_release(&path_copy);
 249         errno = save_errno;
 250         return ret;
 251 }
 252
 253 static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 254 {
 255         int i;
 256         for (i = 0; i < 20; i++) {
 257                 static char hex[] = "0123456789abcdef";
 258                 unsigned int val = sha1[i];
 259                 strbuf_addch(buf, hex[val >> 4]);
 260                 strbuf_addch(buf, hex[val & 0xf]);
 261                 if (!i)
 262                         strbuf_addch(buf, '/');
 263         }
 264 }
 265
 266 const char *sha1_file_name(const unsigned char *sha1)
 267 {
 268         static struct strbuf buf = STRBUF_INIT;
 269
 270         strbuf_reset(&buf);
 271         strbuf_addf(&buf, "%s/", get_object_directory());
 272
 273         fill_sha1_path(&buf, sha1);
 274         return buf.buf;
 275 }
 276
 277 struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 278 {
 279         strbuf_setlen(&alt->scratch, alt->base_len);
 280         return &alt->scratch;
 281 }
 282
 283 static const char *alt_sha1_path(struct alternate_object_database *alt,
 284                                  const unsigned char *sha1)
 285 {
 286         struct strbuf *buf = alt_scratch_buf(alt);
 287         fill_sha1_path(buf, sha1);
 288         return buf->buf;
 289 }
 290
 291 struct alternate_object_database *alt_odb_list;
 292 static struct alternate_object_database **alt_odb_tail;
 293
 294 /*
 295  * Return non-zero iff the path is usable as an alternate object database.
 296  */
 297 static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 298 {
 299         struct alternate_object_database *alt;
 300
 301         /* Detect cases where alternate disappeared */
 302         if (!is_directory(path->buf)) {
 303                 error("object directory %s does not exist; "
 304                       "check .git/objects/info/alternates.",
 305                       path->buf);
 306                 return 0;
 307         }
 308
 309         /*
 310          * Prevent the common mistake of listing the same
 311          * thing twice, or object directory itself.
 312          */
 313         for (alt = alt_odb_list; alt; alt = alt->next) {
 314                 if (!fspathcmp(path->buf, alt->path))
 315                         return 0;
 316         }
 317         if (!fspathcmp(path->buf, normalized_objdir))
 318                 return 0;
 319
 320         return 1;
 321 }
 322
 323 /*
 324  * Prepare alternate object database registry.
 325  *
 326  * The variable alt_odb_list points at the list of struct
 327  * alternate_object_database.  The elements on this list come from
 328  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 329  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 330  * whose contents is similar to that environment variable but can be
 331  * LF separated.  Its base points at a statically allocated buffer that
 332  * contains "/the/directory/corresponding/to/.git/objects/...", while
 333  * its name points just after the slash at the end of ".git/objects/"
 334  * in the example above, and has enough space to hold 40-byte hex
 335  * SHA1, an extra slash for the first level indirection, and the
 336  * terminating NUL.
 337  */
 338 static void read_info_alternates(const char * relative_base, int depth);
 339 static int link_alt_odb_entry(const char *entry, const char *relative_base,
 340         int depth, const char *normalized_objdir)
 341 {
 342         struct alternate_object_database *ent;
 343         struct strbuf pathbuf = STRBUF_INIT;
 344
 345         if (!is_absolute_path(entry) && relative_base) {
 346                 strbuf_realpath(&pathbuf, relative_base, 1);
 347                 strbuf_addch(&pathbuf, '/');
 348         }
 349         strbuf_addstr(&pathbuf, entry);
 350
 351         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 352                 error("unable to normalize alternate object path: %s",
 353                       pathbuf.buf);
 354                 strbuf_release(&pathbuf);
 355                 return -1;
 356         }
 357
 358         /*
 359          * The trailing slash after the directory name is given by
 360          * this function at the end. Remove duplicates.
 361          */
 362         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 363                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
 364
 365         if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 366                 strbuf_release(&pathbuf);
 367                 return -1;
 368         }
 369
 370         ent = alloc_alt_odb(pathbuf.buf);
 371
 372         /* add the alternate entry */
 373         *alt_odb_tail = ent;
 374         alt_odb_tail = &(ent->next);
 375         ent->next = NULL;
 376
 377         /* recursively add alternates */
 378         read_info_alternates(pathbuf.buf, depth + 1);
 379
 380         strbuf_release(&pathbuf);
 381         return 0;
 382 }
 383
 384 static const char *parse_alt_odb_entry(const char *string,
 385                                        int sep,
 386                                        struct strbuf *out)
 387 {
 388         const char *end;
 389
 390         strbuf_reset(out);
 391
 392         if (*string == '#') {
 393                 /* comment; consume up to next separator */
 394                 end = strchrnul(string, sep);
 395         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 396                 /*
 397                  * quoted path; unquote_c_style has copied the
 398                  * data for us and set "end". Broken quoting (e.g.,
 399                  * an entry that doesn't end with a quote) falls
 400                  * back to the unquoted case below.
 401                  */
 402         } else {
 403                 /* normal, unquoted path */
 404                 end = strchrnul(string, sep);
 405                 strbuf_add(out, string, end - string);
 406         }
 407
 408         if (*end)
 409                 end++;
 410         return end;
 411 }
 412
 413 static void link_alt_odb_entries(const char *alt, int sep,
 414                                  const char *relative_base, int depth)
 415 {
 416         struct strbuf objdirbuf = STRBUF_INIT;
 417         struct strbuf entry = STRBUF_INIT;
 418
 419         if (!alt || !*alt)
 420                 return;
 421
 422         if (depth > 5) {
 423                 error("%s: ignoring alternate object stores, nesting too deep.",
 424                                 relative_base);
 425                 return;
 426         }
 427
 428         strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 429         if (strbuf_normalize_path(&objdirbuf) < 0)
 430                 die("unable to normalize object directory: %s",
 431                     objdirbuf.buf);
 432
 433         while (*alt) {
 434                 alt = parse_alt_odb_entry(alt, sep, &entry);
 435                 if (!entry.len)
 436                         continue;
 437                 link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 438         }
 439         strbuf_release(&entry);
 440         strbuf_release(&objdirbuf);
 441 }
 442
 443 static void read_info_alternates(const char * relative_base, int depth)
 444 {
 445         char *path;
 446         struct strbuf buf = STRBUF_INIT;
 447
 448         path = xstrfmt("%s/info/alternates", relative_base);
 449         if (strbuf_read_file(&buf, path, 1024) < 0) {
 450                 warn_on_fopen_errors(path);
 451                 free(path);
 452                 return;
 453         }
 454
 455         link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 456         strbuf_release(&buf);
 457         free(path);
 458 }
 459
 460 struct alternate_object_database *alloc_alt_odb(const char *dir)
 461 {
 462         struct alternate_object_database *ent;
 463
 464         FLEX_ALLOC_STR(ent, path, dir);
 465         strbuf_init(&ent->scratch, 0);
 466         strbuf_addf(&ent->scratch, "%s/", dir);
 467         ent->base_len = ent->scratch.len;
 468
 469         return ent;
 470 }
 471
 472 void add_to_alternates_file(const char *reference)
 473 {
 474         struct lock_file lock = LOCK_INIT;
 475         char *alts = git_pathdup("objects/info/alternates");
 476         FILE *in, *out;
 477         int found = 0;
 478
 479         hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 480         out = fdopen_lock_file(&lock, "w");
 481         if (!out)
 482                 die_errno("unable to fdopen alternates lockfile");
 483
 484         in = fopen(alts, "r");
 485         if (in) {
 486                 struct strbuf line = STRBUF_INIT;
 487
 488                 while (strbuf_getline(&line, in) != EOF) {
 489                         if (!strcmp(reference, line.buf)) {
 490                                 found = 1;
 491                                 break;
 492                         }
 493                         fprintf_or_die(out, "%s\n", line.buf);
 494                 }
 495
 496                 strbuf_release(&line);
 497                 fclose(in);
 498         }
 499         else if (errno != ENOENT)
 500                 die_errno("unable to read alternates file");
 501
 502         if (found) {
 503                 rollback_lock_file(&lock);
 504         } else {
 505                 fprintf_or_die(out, "%s\n", reference);
 506                 if (commit_lock_file(&lock))
 507                         die_errno("unable to move new alternates file into place");
 508                 if (alt_odb_tail)
 509                         link_alt_odb_entries(reference, '\n', NULL, 0);
 510         }
 511         free(alts);
 512 }
 513
 514 void add_to_alternates_memory(const char *reference)
 515 {
 516         /*
 517          * Make sure alternates are initialized, or else our entry may be
 518          * overwritten when they are.
 519          */
 520         prepare_alt_odb();
 521
 522         link_alt_odb_entries(reference, '\n', NULL, 0);
 523 }
 524
 525 /*
 526  * Compute the exact path an alternate is at and returns it. In case of
 527  * error NULL is returned and the human readable error is added to `err`
 528  * `path` may be relative and should point to $GITDIR.
 529  * `err` must not be null.
 530  */
 531 char *compute_alternate_path(const char *path, struct strbuf *err)
 532 {
 533         char *ref_git = NULL;
 534         const char *repo, *ref_git_s;
 535         int seen_error = 0;
 536
 537         ref_git_s = real_path_if_valid(path);
 538         if (!ref_git_s) {
 539                 seen_error = 1;
 540                 strbuf_addf(err, _("path '%s' does not exist"), path);
 541                 goto out;
 542         } else
 543                 /*
 544                  * Beware: read_gitfile(), real_path() and mkpath()
 545                  * return static buffer
 546                  */
 547                 ref_git = xstrdup(ref_git_s);
 548
 549         repo = read_gitfile(ref_git);
 550         if (!repo)
 551                 repo = read_gitfile(mkpath("%s/.git", ref_git));
 552         if (repo) {
 553                 free(ref_git);
 554                 ref_git = xstrdup(repo);
 555         }
 556
 557         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 558                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
 559                 free(ref_git);
 560                 ref_git = ref_git_git;
 561         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 562                 struct strbuf sb = STRBUF_INIT;
 563                 seen_error = 1;
 564                 if (get_common_dir(&sb, ref_git)) {
 565                         strbuf_addf(err,
 566                                     _("reference repository '%s' as a linked "
 567                                       "checkout is not supported yet."),
 568                                     path);
 569                         goto out;
 570                 }
 571
 572                 strbuf_addf(err, _("reference repository '%s' is not a "
 573                                         "local repository."), path);
 574                 goto out;
 575         }
 576
 577         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 578                 strbuf_addf(err, _("reference repository '%s' is shallow"),
 579                             path);
 580                 seen_error = 1;
 581                 goto out;
 582         }
 583
 584         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 585                 strbuf_addf(err,
 586                             _("reference repository '%s' is grafted"),
 587                             path);
 588                 seen_error = 1;
 589                 goto out;
 590         }
 591
 592 out:
 593         if (seen_error) {
 594                 FREE_AND_NULL(ref_git);
 595         }
 596
 597         return ref_git;
 598 }
 599
 600 int foreach_alt_odb(alt_odb_fn fn, void *cb)
 601 {
 602         struct alternate_object_database *ent;
 603         int r = 0;
 604
 605         prepare_alt_odb();
 606         for (ent = alt_odb_list; ent; ent = ent->next) {
 607                 r = fn(ent, cb);
 608                 if (r)
 609                         break;
 610         }
 611         return r;
 612 }
 613
 614 void prepare_alt_odb(void)
 615 {
 616         const char *alt;
 617
 618         if (alt_odb_tail)
 619                 return;
 620
 621         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 622
 623         alt_odb_tail = &alt_odb_list;
 624         link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
 625
 626         read_info_alternates(get_object_directory(), 0);
 627 }
 628
 629 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 630 static int freshen_file(const char *fn)
 631 {
 632         struct utimbuf t;
 633         t.actime = t.modtime = time(NULL);
 634         return !utime(fn, &t);
 635 }
 636
 637 /*
 638  * All of the check_and_freshen functions return 1 if the file exists and was
 639  * freshened (if freshening was requested), 0 otherwise. If they return
 640  * 0, you should not assume that it is safe to skip a write of the object (it
 641  * either does not exist on disk, or has a stale mtime and may be subject to
 642  * pruning).
 643  */
 644 int check_and_freshen_file(const char *fn, int freshen)
 645 {
 646         if (access(fn, F_OK))
 647                 return 0;
 648         if (freshen && !freshen_file(fn))
 649                 return 0;
 650         return 1;
 651 }
 652
 653 static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 654 {
 655         return check_and_freshen_file(sha1_file_name(sha1), freshen);
 656 }
 657
 658 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 659 {
 660         struct alternate_object_database *alt;
 661         prepare_alt_odb();
 662         for (alt = alt_odb_list; alt; alt = alt->next) {
 663                 const char *path = alt_sha1_path(alt, sha1);
 664                 if (check_and_freshen_file(path, freshen))
 665                         return 1;
 666         }
 667         return 0;
 668 }
 669
 670 static int check_and_freshen(const unsigned char *sha1, int freshen)
 671 {
 672         return check_and_freshen_local(sha1, freshen) ||
 673                check_and_freshen_nonlocal(sha1, freshen);
 674 }
 675
 676 int has_loose_object_nonlocal(const unsigned char *sha1)
 677 {
 678         return check_and_freshen_nonlocal(sha1, 0);
 679 }
 680
 681 static int has_loose_object(const unsigned char *sha1)
 682 {
 683         return check_and_freshen(sha1, 0);
 684 }
 685
 686 static void mmap_limit_check(size_t length)
 687 {
 688         static size_t limit = 0;
 689         if (!limit) {
 690                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 691                 if (!limit)
 692                         limit = SIZE_MAX;
 693         }
 694         if (length > limit)
 695                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 696                     (uintmax_t)length, (uintmax_t)limit);
 697 }
 698
 699 void *xmmap_gently(void *start, size_t length,
 700                   int prot, int flags, int fd, off_t offset)
 701 {
 702         void *ret;
 703
 704         mmap_limit_check(length);
 705         ret = mmap(start, length, prot, flags, fd, offset);
 706         if (ret == MAP_FAILED) {
 707                 if (!length)
 708                         return NULL;
 709                 release_pack_memory(length);
 710                 ret = mmap(start, length, prot, flags, fd, offset);
 711         }
 712         return ret;
 713 }
 714
 715 void *xmmap(void *start, size_t length,
 716         int prot, int flags, int fd, off_t offset)
 717 {
 718         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 719         if (ret == MAP_FAILED)
 720                 die_errno("mmap failed");
 721         return ret;
 722 }
 723
 724 /*
 725  * With an in-core object data in "map", rehash it to make sure the
 726  * object name actually matches "sha1" to detect object corruption.
 727  * With "map" == NULL, try reading the object named with "sha1" using
 728  * the streaming interface and rehash it to do the same.
 729  */
 730 int check_sha1_signature(const unsigned char *sha1, void *map,
 731                          unsigned long size, const char *type)
 732 {
 733         unsigned char real_sha1[20];
 734         enum object_type obj_type;
 735         struct git_istream *st;
 736         git_SHA_CTX c;
 737         char hdr[32];
 738         int hdrlen;
 739
 740         if (map) {
 741                 hash_sha1_file(map, size, type, real_sha1);
 742                 return hashcmp(sha1, real_sha1) ? -1 : 0;
 743         }
 744
 745         st = open_istream(sha1, &obj_type, &size, NULL);
 746         if (!st)
 747                 return -1;
 748
 749         /* Generate the header */
 750         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 751
 752         /* Sha1.. */
 753         git_SHA1_Init(&c);
 754         git_SHA1_Update(&c, hdr, hdrlen);
 755         for (;;) {
 756                 char buf[1024 * 16];
 757                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
 758
 759                 if (readlen < 0) {
 760                         close_istream(st);
 761                         return -1;
 762                 }
 763                 if (!readlen)
 764                         break;
 765                 git_SHA1_Update(&c, buf, readlen);
 766         }
 767         git_SHA1_Final(real_sha1, &c);
 768         close_istream(st);
 769         return hashcmp(sha1, real_sha1) ? -1 : 0;
 770 }
 771
 772 int git_open_cloexec(const char *name, int flags)
 773 {
 774         int fd;
 775         static int o_cloexec = O_CLOEXEC;
 776
 777         fd = open(name, flags | o_cloexec);
 778         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 779                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
 780                 o_cloexec &= ~O_CLOEXEC;
 781                 fd = open(name, flags | o_cloexec);
 782         }
 783
 784 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 785         {
 786                 static int fd_cloexec = FD_CLOEXEC;
 787
 788                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
 789                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 790                         int flags = fcntl(fd, F_GETFD);
 791                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 792                                 fd_cloexec = 0;
 793                 }
 794         }
 795 #endif
 796         return fd;
 797 }
 798
 799 /*
 800  * Find "sha1" as a loose object in the local repository or in an alternate.
 801  * Returns 0 on success, negative on failure.
 802  *
 803  * The "path" out-parameter will give the path of the object we found (if any).
 804  * Note that it may point to static storage and is only valid until another
 805  * call to sha1_file_name(), etc.
 806  */
 807 static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 808                           const char **path)
 809 {
 810         struct alternate_object_database *alt;
 811
 812         *path = sha1_file_name(sha1);
 813         if (!lstat(*path, st))
 814                 return 0;
 815
 816         prepare_alt_odb();
 817         errno = ENOENT;
 818         for (alt = alt_odb_list; alt; alt = alt->next) {
 819                 *path = alt_sha1_path(alt, sha1);
 820                 if (!lstat(*path, st))
 821                         return 0;
 822         }
 823
 824         return -1;
 825 }
 826
 827 /*
 828  * Like stat_sha1_file(), but actually open the object and return the
 829  * descriptor. See the caveats on the "path" parameter above.
 830  */
 831 static int open_sha1_file(const unsigned char *sha1, const char **path)
 832 {
 833         int fd;
 834         struct alternate_object_database *alt;
 835         int most_interesting_errno;
 836
 837         *path = sha1_file_name(sha1);
 838         fd = git_open(*path);
 839         if (fd >= 0)
 840                 return fd;
 841         most_interesting_errno = errno;
 842
 843         prepare_alt_odb();
 844         for (alt = alt_odb_list; alt; alt = alt->next) {
 845                 *path = alt_sha1_path(alt, sha1);
 846                 fd = git_open(*path);
 847                 if (fd >= 0)
 848                         return fd;
 849                 if (most_interesting_errno == ENOENT)
 850                         most_interesting_errno = errno;
 851         }
 852         errno = most_interesting_errno;
 853         return -1;
 854 }
 855
 856 /*
 857  * Map the loose object at "path" if it is not NULL, or the path found by
 858  * searching for a loose object named "sha1".
 859  */
 860 static void *map_sha1_file_1(const char *path,
 861                              const unsigned char *sha1,
 862                              unsigned long *size)
 863 {
 864         void *map;
 865         int fd;
 866
 867         if (path)
 868                 fd = git_open(path);
 869         else
 870                 fd = open_sha1_file(sha1, &path);
 871         map = NULL;
 872         if (fd >= 0) {
 873                 struct stat st;
 874
 875                 if (!fstat(fd, &st)) {
 876                         *size = xsize_t(st.st_size);
 877                         if (!*size) {
 878                                 /* mmap() is forbidden on empty files */
 879                                 error("object file %s is empty", path);
 880                                 return NULL;
 881                         }
 882                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 883                 }
 884                 close(fd);
 885         }
 886         return map;
 887 }
 888
 889 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 890 {
 891         return map_sha1_file_1(NULL, sha1, size);
 892 }
 893
 894 static int unpack_sha1_short_header(git_zstream *stream,
 895                                     unsigned char *map, unsigned long mapsize,
 896                                     void *buffer, unsigned long bufsiz)
 897 {
 898         /* Get the data stream */
 899         memset(stream, 0, sizeof(*stream));
 900         stream->next_in = map;
 901         stream->avail_in = mapsize;
 902         stream->next_out = buffer;
 903         stream->avail_out = bufsiz;
 904
 905         git_inflate_init(stream);
 906         return git_inflate(stream, 0);
 907 }
 908
 909 int unpack_sha1_header(git_zstream *stream,
 910                        unsigned char *map, unsigned long mapsize,
 911                        void *buffer, unsigned long bufsiz)
 912 {
 913         int status = unpack_sha1_short_header(stream, map, mapsize,
 914                                               buffer, bufsiz);
 915
 916         if (status < Z_OK)
 917                 return status;
 918
 919         /* Make sure we have the terminating NUL */
 920         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 921                 return -1;
 922         return 0;
 923 }
 924
 925 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 926                                         unsigned long mapsize, void *buffer,
 927                                         unsigned long bufsiz, struct strbuf *header)
 928 {
 929         int status;
 930
 931         status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 932         if (status < Z_OK)
 933                 return -1;
 934
 935         /*
 936          * Check if entire header is unpacked in the first iteration.
 937          */
 938         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 939                 return 0;
 940
 941         /*
 942          * buffer[0..bufsiz] was not large enough.  Copy the partial
 943          * result out to header, and then append the result of further
 944          * reading the stream.
 945          */
 946         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 947         stream->next_out = buffer;
 948         stream->avail_out = bufsiz;
 949
 950         do {
 951                 status = git_inflate(stream, 0);
 952                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 953                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 954                         return 0;
 955                 stream->next_out = buffer;
 956                 stream->avail_out = bufsiz;
 957         } while (status != Z_STREAM_END);
 958         return -1;
 959 }
 960
 961 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 962 {
 963         int bytes = strlen(buffer) + 1;
 964         unsigned char *buf = xmallocz(size);
 965         unsigned long n;
 966         int status = Z_OK;
 967
 968         n = stream->total_out - bytes;
 969         if (n > size)
 970                 n = size;
 971         memcpy(buf, (char *) buffer + bytes, n);
 972         bytes = n;
 973         if (bytes <= size) {
 974                 /*
 975                  * The above condition must be (bytes <= size), not
 976                  * (bytes < size).  In other words, even though we
 977                  * expect no more output and set avail_out to zero,
 978                  * the input zlib stream may have bytes that express
 979                  * "this concludes the stream", and we *do* want to
 980                  * eat that input.
 981                  *
 982                  * Otherwise we would not be able to test that we
 983                  * consumed all the input to reach the expected size;
 984                  * we also want to check that zlib tells us that all
 985                  * went well with status == Z_STREAM_END at the end.
 986                  */
 987                 stream->next_out = buf + bytes;
 988                 stream->avail_out = size - bytes;
 989                 while (status == Z_OK)
 990                         status = git_inflate(stream, Z_FINISH);
 991         }
 992         if (status == Z_STREAM_END && !stream->avail_in) {
 993                 git_inflate_end(stream);
 994                 return buf;
 995         }
 996
 997         if (status < 0)
 998                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
 999         else if (stream->avail_in)
1000                 error("garbage at end of loose object '%s'",
1001                       sha1_to_hex(sha1));
1002         free(buf);
1003         return NULL;
1004 }
1005
1006 /*
1007  * We used to just use "sscanf()", but that's actually way
1008  * too permissive for what we want to check. So do an anal
1009  * object header parse by hand.
1010  */
1011 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1012                                unsigned int flags)
1013 {
1014         const char *type_buf = hdr;
1015         unsigned long size;
1016         int type, type_len = 0;
1017
1018         /*
1019          * The type can be of any size but is followed by
1020          * a space.
1021          */
1022         for (;;) {
1023                 char c = *hdr++;
1024                 if (!c)
1025                         return -1;
1026                 if (c == ' ')
1027                         break;
1028                 type_len++;
1029         }
1030
1031         type = type_from_string_gently(type_buf, type_len, 1);
1032         if (oi->typename)
1033                 strbuf_add(oi->typename, type_buf, type_len);
1034         /*
1035          * Set type to 0 if its an unknown object and
1036          * we're obtaining the type using '--allow-unknown-type'
1037          * option.
1038          */
1039         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1040                 type = 0;
1041         else if (type < 0)
1042                 die("invalid object type");
1043         if (oi->typep)
1044                 *oi->typep = type;
1045
1046         /*
1047          * The length must follow immediately, and be in canonical
1048          * decimal format (ie "010" is not valid).
1049          */
1050         size = *hdr++ - '0';
1051         if (size > 9)
1052                 return -1;
1053         if (size) {
1054                 for (;;) {
1055                         unsigned long c = *hdr - '0';
1056                         if (c > 9)
1057                                 break;
1058                         hdr++;
1059                         size = size * 10 + c;
1060                 }
1061         }
1062
1063         if (oi->sizep)
1064                 *oi->sizep = size;
1065
1066         /*
1067          * The length must be followed by a zero byte
1068          */
1069         return *hdr ? -1 : type;
1070 }
1071
1072 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1073 {
1074         struct object_info oi = OBJECT_INFO_INIT;
1075
1076         oi.sizep = sizep;
1077         return parse_sha1_header_extended(hdr, &oi, 0);
1078 }
1079
1080 static int sha1_loose_object_info(const unsigned char *sha1,
1081                                   struct object_info *oi,
1082                                   int flags)
1083 {
1084         int status = 0;
1085         unsigned long mapsize;
1086         void *map;
1087         git_zstream stream;
1088         char hdr[32];
1089         struct strbuf hdrbuf = STRBUF_INIT;
1090         unsigned long size_scratch;
1091
1092         if (oi->delta_base_sha1)
1093                 hashclr(oi->delta_base_sha1);
1094
1095         /*
1096          * If we don't care about type or size, then we don't
1097          * need to look inside the object at all. Note that we
1098          * do not optimize out the stat call, even if the
1099          * caller doesn't care about the disk-size, since our
1100          * return value implicitly indicates whether the
1101          * object even exists.
1102          */
1103         if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1104                 const char *path;
1105                 struct stat st;
1106                 if (stat_sha1_file(sha1, &st, &path) < 0)
1107                         return -1;
1108                 if (oi->disk_sizep)
1109                         *oi->disk_sizep = st.st_size;
1110                 return 0;
1111         }
1112
1113         map = map_sha1_file(sha1, &mapsize);
1114         if (!map)
1115                 return -1;
1116
1117         if (!oi->sizep)
1118                 oi->sizep = &size_scratch;
1119
1120         if (oi->disk_sizep)
1121                 *oi->disk_sizep = mapsize;
1122         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1123                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1124                         status = error("unable to unpack %s header with --allow-unknown-type",
1125                                        sha1_to_hex(sha1));
1126         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1127                 status = error("unable to unpack %s header",
1128                                sha1_to_hex(sha1));
1129         if (status < 0)
1130                 ; /* Do nothing */
1131         else if (hdrbuf.len) {
1132                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1133                         status = error("unable to parse %s header with --allow-unknown-type",
1134                                        sha1_to_hex(sha1));
1135         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1136                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1137
1138         if (status >= 0 && oi->contentp) {
1139                 *oi->contentp = unpack_sha1_rest(&stream, hdr,
1140                                                  *oi->sizep, sha1);
1141                 if (!*oi->contentp) {
1142                         git_inflate_end(&stream);
1143                         status = -1;
1144                 }
1145         } else
1146                 git_inflate_end(&stream);
1147
1148         munmap(map, mapsize);
1149         if (status && oi->typep)
1150                 *oi->typep = status;
1151         if (oi->sizep == &size_scratch)
1152                 oi->sizep = NULL;
1153         strbuf_release(&hdrbuf);
1154         oi->whence = OI_LOOSE;
1155         return (status < 0) ? status : 0;
1156 }
1157
1158 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1159 {
1160         static struct object_info blank_oi = OBJECT_INFO_INIT;
1161         struct pack_entry e;
1162         int rtype;
1163         const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1164                                     lookup_replace_object(sha1) :
1165                                     sha1;
1166
1167         if (!oi)
1168                 oi = &blank_oi;
1169
1170         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1171                 struct cached_object *co = find_cached_object(real);
1172                 if (co) {
1173                         if (oi->typep)
1174                                 *(oi->typep) = co->type;
1175                         if (oi->sizep)
1176                                 *(oi->sizep) = co->size;
1177                         if (oi->disk_sizep)
1178                                 *(oi->disk_sizep) = 0;
1179                         if (oi->delta_base_sha1)
1180                                 hashclr(oi->delta_base_sha1);
1181                         if (oi->typename)
1182                                 strbuf_addstr(oi->typename, typename(co->type));
1183                         if (oi->contentp)
1184                                 *oi->contentp = xmemdupz(co->buf, co->size);
1185                         oi->whence = OI_CACHED;
1186                         return 0;
1187                 }
1188         }
1189
1190         if (!find_pack_entry(real, &e)) {
1191                 /* Most likely it's a loose object. */
1192                 if (!sha1_loose_object_info(real, oi, flags))
1193                         return 0;
1194
1195                 /* Not a loose object; someone else may have just packed it. */
1196                 if (flags & OBJECT_INFO_QUICK) {
1197                         return -1;
1198                 } else {
1199                         reprepare_packed_git();
1200                         if (!find_pack_entry(real, &e))
1201                                 return -1;
1202                 }
1203         }
1204
1205         if (oi == &blank_oi)
1206                 /*
1207                  * We know that the caller doesn't actually need the
1208                  * information below, so return early.
1209                  */
1210                 return 0;
1211
1212         rtype = packed_object_info(e.p, e.offset, oi);
1213         if (rtype < 0) {
1214                 mark_bad_packed_object(e.p, real);
1215                 return sha1_object_info_extended(real, oi, 0);
1216         } else if (oi->whence == OI_PACKED) {
1217                 oi->u.packed.offset = e.offset;
1218                 oi->u.packed.pack = e.p;
1219                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1220                                          rtype == OBJ_OFS_DELTA);
1221         }
1222
1223         return 0;
1224 }
1225
1226 /* returns enum object_type or negative */
1227 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1228 {
1229         enum object_type type;
1230         struct object_info oi = OBJECT_INFO_INIT;
1231
1232         oi.typep = &type;
1233         oi.sizep = sizep;
1234         if (sha1_object_info_extended(sha1, &oi,
1235                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1236                 return -1;
1237         return type;
1238 }
1239
1240 static void *read_object(const unsigned char *sha1, enum object_type *type,
1241                          unsigned long *size)
1242 {
1243         struct object_info oi = OBJECT_INFO_INIT;
1244         void *content;
1245         oi.typep = type;
1246         oi.sizep = size;
1247         oi.contentp = &content;
1248
1249         if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1250                 return NULL;
1251         return content;
1252 }
1253
1254 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1255                       unsigned char *sha1)
1256 {
1257         struct cached_object *co;
1258
1259         hash_sha1_file(buf, len, typename(type), sha1);
1260         if (has_sha1_file(sha1) || find_cached_object(sha1))
1261                 return 0;
1262         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1263         co = &cached_objects[cached_object_nr++];
1264         co->size = len;
1265         co->type = type;
1266         co->buf = xmalloc(len);
1267         memcpy(co->buf, buf, len);
1268         hashcpy(co->sha1, sha1);
1269         return 0;
1270 }
1271
1272 /*
1273  * This function dies on corrupt objects; the callers who want to
1274  * deal with them should arrange to call read_object() and give error
1275  * messages themselves.
1276  */
1277 void *read_sha1_file_extended(const unsigned char *sha1,
1278                               enum object_type *type,
1279                               unsigned long *size,
1280                               int lookup_replace)
1281 {
1282         void *data;
1283         const struct packed_git *p;
1284         const char *path;
1285         struct stat st;
1286         const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1287                                                    : sha1;
1288
1289         errno = 0;
1290         data = read_object(repl, type, size);
1291         if (data)
1292                 return data;
1293
1294         if (errno && errno != ENOENT)
1295                 die_errno("failed to read object %s", sha1_to_hex(sha1));
1296
1297         /* die if we replaced an object with one that does not exist */
1298         if (repl != sha1)
1299                 die("replacement %s not found for %s",
1300                     sha1_to_hex(repl), sha1_to_hex(sha1));
1301
1302         if (!stat_sha1_file(repl, &st, &path))
1303                 die("loose object %s (stored in %s) is corrupt",
1304                     sha1_to_hex(repl), path);
1305
1306         if ((p = has_packed_and_bad(repl)) != NULL)
1307                 die("packed object %s (stored in %s) is corrupt",
1308                     sha1_to_hex(repl), p->pack_name);
1309
1310         return NULL;
1311 }
1312
1313 void *read_object_with_reference(const unsigned char *sha1,
1314                                  const char *required_type_name,
1315                                  unsigned long *size,
1316                                  unsigned char *actual_sha1_return)
1317 {
1318         enum object_type type, required_type;
1319         void *buffer;
1320         unsigned long isize;
1321         unsigned char actual_sha1[20];
1322
1323         required_type = type_from_string(required_type_name);
1324         hashcpy(actual_sha1, sha1);
1325         while (1) {
1326                 int ref_length = -1;
1327                 const char *ref_type = NULL;
1328
1329                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1330                 if (!buffer)
1331                         return NULL;
1332                 if (type == required_type) {
1333                         *size = isize;
1334                         if (actual_sha1_return)
1335                                 hashcpy(actual_sha1_return, actual_sha1);
1336                         return buffer;
1337                 }
1338                 /* Handle references */
1339                 else if (type == OBJ_COMMIT)
1340                         ref_type = "tree ";
1341                 else if (type == OBJ_TAG)
1342                         ref_type = "object ";
1343                 else {
1344                         free(buffer);
1345                         return NULL;
1346                 }
1347                 ref_length = strlen(ref_type);
1348
1349                 if (ref_length + 40 > isize ||
1350                     memcmp(buffer, ref_type, ref_length) ||
1351                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1352                         free(buffer);
1353                         return NULL;
1354                 }
1355                 free(buffer);
1356                 /* Now we have the ID of the referred-to object in
1357                  * actual_sha1.  Check again. */
1358         }
1359 }
1360
1361 static void write_sha1_file_prepare(const void *buf, unsigned long len,
1362                                     const char *type, unsigned char *sha1,
1363                                     char *hdr, int *hdrlen)
1364 {
1365         git_SHA_CTX c;
1366
1367         /* Generate the header */
1368         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1369
1370         /* Sha1.. */
1371         git_SHA1_Init(&c);
1372         git_SHA1_Update(&c, hdr, *hdrlen);
1373         git_SHA1_Update(&c, buf, len);
1374         git_SHA1_Final(sha1, &c);
1375 }
1376
1377 /*
1378  * Move the just written object into its final resting place.
1379  */
1380 int finalize_object_file(const char *tmpfile, const char *filename)
1381 {
1382         int ret = 0;
1383
1384         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1385                 goto try_rename;
1386         else if (link(tmpfile, filename))
1387                 ret = errno;
1388
1389         /*
1390          * Coda hack - coda doesn't like cross-directory links,
1391          * so we fall back to a rename, which will mean that it
1392          * won't be able to check collisions, but that's not a
1393          * big deal.
1394          *
1395          * The same holds for FAT formatted media.
1396          *
1397          * When this succeeds, we just return.  We have nothing
1398          * left to unlink.
1399          */
1400         if (ret && ret != EEXIST) {
1401         try_rename:
1402                 if (!rename(tmpfile, filename))
1403                         goto out;
1404                 ret = errno;
1405         }
1406         unlink_or_warn(tmpfile);
1407         if (ret) {
1408                 if (ret != EEXIST) {
1409                         return error_errno("unable to write sha1 filename %s", filename);
1410                 }
1411                 /* FIXME!!! Collision check here ? */
1412         }
1413
1414 out:
1415         if (adjust_shared_perm(filename))
1416                 return error("unable to set permission to '%s'", filename);
1417         return 0;
1418 }
1419
1420 static int write_buffer(int fd, const void *buf, size_t len)
1421 {
1422         if (write_in_full(fd, buf, len) < 0)
1423                 return error_errno("file write error");
1424         return 0;
1425 }
1426
1427 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1428                    unsigned char *sha1)
1429 {
1430         char hdr[32];
1431         int hdrlen = sizeof(hdr);
1432         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1433         return 0;
1434 }
1435
1436 /* Finalize a file on disk, and close it. */
1437 static void close_sha1_file(int fd)
1438 {
1439         if (fsync_object_files)
1440                 fsync_or_die(fd, "sha1 file");
1441         if (close(fd) != 0)
1442                 die_errno("error when closing sha1 file");
1443 }
1444
1445 /* Size of directory component, including the ending '/' */
1446 static inline int directory_size(const char *filename)
1447 {
1448         const char *s = strrchr(filename, '/');
1449         if (!s)
1450                 return 0;
1451         return s - filename + 1;
1452 }
1453
1454 /*
1455  * This creates a temporary file in the same directory as the final
1456  * 'filename'
1457  *
1458  * We want to avoid cross-directory filename renames, because those
1459  * can have problems on various filesystems (FAT, NFS, Coda).
1460  */
1461 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1462 {
1463         int fd, dirlen = directory_size(filename);
1464
1465         strbuf_reset(tmp);
1466         strbuf_add(tmp, filename, dirlen);
1467         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1468         fd = git_mkstemp_mode(tmp->buf, 0444);
1469         if (fd < 0 && dirlen && errno == ENOENT) {
1470                 /*
1471                  * Make sure the directory exists; note that the contents
1472                  * of the buffer are undefined after mkstemp returns an
1473                  * error, so we have to rewrite the whole buffer from
1474                  * scratch.
1475                  */
1476                 strbuf_reset(tmp);
1477                 strbuf_add(tmp, filename, dirlen - 1);
1478                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1479                         return -1;
1480                 if (adjust_shared_perm(tmp->buf))
1481                         return -1;
1482
1483                 /* Try again */
1484                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1485                 fd = git_mkstemp_mode(tmp->buf, 0444);
1486         }
1487         return fd;
1488 }
1489
1490 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1491                               const void *buf, unsigned long len, time_t mtime)
1492 {
1493         int fd, ret;
1494         unsigned char compressed[4096];
1495         git_zstream stream;
1496         git_SHA_CTX c;
1497         unsigned char parano_sha1[20];
1498         static struct strbuf tmp_file = STRBUF_INIT;
1499         const char *filename = sha1_file_name(sha1);
1500
1501         fd = create_tmpfile(&tmp_file, filename);
1502         if (fd < 0) {
1503                 if (errno == EACCES)
1504                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1505                 else
1506                         return error_errno("unable to create temporary file");
1507         }
1508
1509         /* Set it up */
1510         git_deflate_init(&stream, zlib_compression_level);
1511         stream.next_out = compressed;
1512         stream.avail_out = sizeof(compressed);
1513         git_SHA1_Init(&c);
1514
1515         /* First header.. */
1516         stream.next_in = (unsigned char *)hdr;
1517         stream.avail_in = hdrlen;
1518         while (git_deflate(&stream, 0) == Z_OK)
1519                 ; /* nothing */
1520         git_SHA1_Update(&c, hdr, hdrlen);
1521
1522         /* Then the data itself.. */
1523         stream.next_in = (void *)buf;
1524         stream.avail_in = len;
1525         do {
1526                 unsigned char *in0 = stream.next_in;
1527                 ret = git_deflate(&stream, Z_FINISH);
1528                 git_SHA1_Update(&c, in0, stream.next_in - in0);
1529                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1530                         die("unable to write sha1 file");
1531                 stream.next_out = compressed;
1532                 stream.avail_out = sizeof(compressed);
1533         } while (ret == Z_OK);
1534
1535         if (ret != Z_STREAM_END)
1536                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1537         ret = git_deflate_end_gently(&stream);
1538         if (ret != Z_OK)
1539                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1540         git_SHA1_Final(parano_sha1, &c);
1541         if (hashcmp(sha1, parano_sha1) != 0)
1542                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1543
1544         close_sha1_file(fd);
1545
1546         if (mtime) {
1547                 struct utimbuf utb;
1548                 utb.actime = mtime;
1549                 utb.modtime = mtime;
1550                 if (utime(tmp_file.buf, &utb) < 0)
1551                         warning_errno("failed utime() on %s", tmp_file.buf);
1552         }
1553
1554         return finalize_object_file(tmp_file.buf, filename);
1555 }
1556
1557 static int freshen_loose_object(const unsigned char *sha1)
1558 {
1559         return check_and_freshen(sha1, 1);
1560 }
1561
1562 static int freshen_packed_object(const unsigned char *sha1)
1563 {
1564         struct pack_entry e;
1565         if (!find_pack_entry(sha1, &e))
1566                 return 0;
1567         if (e.p->freshened)
1568                 return 1;
1569         if (!freshen_file(e.p->pack_name))
1570                 return 0;
1571         e.p->freshened = 1;
1572         return 1;
1573 }
1574
1575 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1576 {
1577         char hdr[32];
1578         int hdrlen = sizeof(hdr);
1579
1580         /* Normally if we have it in the pack then we do not bother writing
1581          * it out into .git/objects/??/?{38} file.
1582          */
1583         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1584         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1585                 return 0;
1586         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1587 }
1588
1589 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1590                              struct object_id *oid, unsigned flags)
1591 {
1592         char *header;
1593         int hdrlen, status = 0;
1594
1595         /* type string, SP, %lu of the length plus NUL must fit this */
1596         hdrlen = strlen(type) + 32;
1597         header = xmalloc(hdrlen);
1598         write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1599
1600         if (!(flags & HASH_WRITE_OBJECT))
1601                 goto cleanup;
1602         if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1603                 goto cleanup;
1604         status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1605
1606 cleanup:
1607         free(header);
1608         return status;
1609 }
1610
1611 int force_object_loose(const unsigned char *sha1, time_t mtime)
1612 {
1613         void *buf;
1614         unsigned long len;
1615         enum object_type type;
1616         char hdr[32];
1617         int hdrlen;
1618         int ret;
1619
1620         if (has_loose_object(sha1))
1621                 return 0;
1622         buf = read_object(sha1, &type, &len);
1623         if (!buf)
1624                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1625         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1626         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1627         free(buf);
1628
1629         return ret;
1630 }
1631
1632 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1633 {
1634         if (!startup_info->have_repository)
1635                 return 0;
1636         return sha1_object_info_extended(sha1, NULL,
1637                                          flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1638 }
1639
1640 int has_object_file(const struct object_id *oid)
1641 {
1642         return has_sha1_file(oid->hash);
1643 }
1644
1645 int has_object_file_with_flags(const struct object_id *oid, int flags)
1646 {
1647         return has_sha1_file_with_flags(oid->hash, flags);
1648 }
1649
1650 static void check_tree(const void *buf, size_t size)
1651 {
1652         struct tree_desc desc;
1653         struct name_entry entry;
1654
1655         init_tree_desc(&desc, buf, size);
1656         while (tree_entry(&desc, &entry))
1657                 /* do nothing
1658                  * tree_entry() will die() on malformed entries */
1659                 ;
1660 }
1661
1662 static void check_commit(const void *buf, size_t size)
1663 {
1664         struct commit c;
1665         memset(&c, 0, sizeof(c));
1666         if (parse_commit_buffer(&c, buf, size))
1667                 die("corrupt commit");
1668 }
1669
1670 static void check_tag(const void *buf, size_t size)
1671 {
1672         struct tag t;
1673         memset(&t, 0, sizeof(t));
1674         if (parse_tag_buffer(&t, buf, size))
1675                 die("corrupt tag");
1676 }
1677
1678 static int index_mem(struct object_id *oid, void *buf, size_t size,
1679                      enum object_type type,
1680                      const char *path, unsigned flags)
1681 {
1682         int ret, re_allocated = 0;
1683         int write_object = flags & HASH_WRITE_OBJECT;
1684
1685         if (!type)
1686                 type = OBJ_BLOB;
1687
1688         /*
1689          * Convert blobs to git internal format
1690          */
1691         if ((type == OBJ_BLOB) && path) {
1692                 struct strbuf nbuf = STRBUF_INIT;
1693                 if (convert_to_git(&the_index, path, buf, size, &nbuf,
1694                                    get_safe_crlf(flags))) {
1695                         buf = strbuf_detach(&nbuf, &size);
1696                         re_allocated = 1;
1697                 }
1698         }
1699         if (flags & HASH_FORMAT_CHECK) {
1700                 if (type == OBJ_TREE)
1701                         check_tree(buf, size);
1702                 if (type == OBJ_COMMIT)
1703                         check_commit(buf, size);
1704                 if (type == OBJ_TAG)
1705                         check_tag(buf, size);
1706         }
1707
1708         if (write_object)
1709                 ret = write_sha1_file(buf, size, typename(type), oid->hash);
1710         else
1711                 ret = hash_sha1_file(buf, size, typename(type), oid->hash);
1712         if (re_allocated)
1713                 free(buf);
1714         return ret;
1715 }
1716
1717 static int index_stream_convert_blob(struct object_id *oid, int fd,
1718                                      const char *path, unsigned flags)
1719 {
1720         int ret;
1721         const int write_object = flags & HASH_WRITE_OBJECT;
1722         struct strbuf sbuf = STRBUF_INIT;
1723
1724         assert(path);
1725         assert(would_convert_to_git_filter_fd(path));
1726
1727         convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1728                                  get_safe_crlf(flags));
1729
1730         if (write_object)
1731                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1732                                       oid->hash);
1733         else
1734                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1735                                      oid->hash);
1736         strbuf_release(&sbuf);
1737         return ret;
1738 }
1739
1740 static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1741                       const char *path, unsigned flags)
1742 {
1743         struct strbuf sbuf = STRBUF_INIT;
1744         int ret;
1745
1746         if (strbuf_read(&sbuf, fd, 4096) >= 0)
1747                 ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1748         else
1749                 ret = -1;
1750         strbuf_release(&sbuf);
1751         return ret;
1752 }
1753
1754 #define SMALL_FILE_SIZE (32*1024)
1755
1756 static int index_core(struct object_id *oid, int fd, size_t size,
1757                       enum object_type type, const char *path,
1758                       unsigned flags)
1759 {
1760         int ret;
1761
1762         if (!size) {
1763                 ret = index_mem(oid, "", size, type, path, flags);
1764         } else if (size <= SMALL_FILE_SIZE) {
1765                 char *buf = xmalloc(size);
1766                 ssize_t read_result = read_in_full(fd, buf, size);
1767                 if (read_result < 0)
1768                         ret = error_errno("read error while indexing %s",
1769                                           path ? path : "<unknown>");
1770                 else if (read_result != size)
1771                         ret = error("short read while indexing %s",
1772                                     path ? path : "<unknown>");
1773                 else
1774                         ret = index_mem(oid, buf, size, type, path, flags);
1775                 free(buf);
1776         } else {
1777                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1778                 ret = index_mem(oid, buf, size, type, path, flags);
1779                 munmap(buf, size);
1780         }
1781         return ret;
1782 }
1783
1784 /*
1785  * This creates one packfile per large blob unless bulk-checkin
1786  * machinery is "plugged".
1787  *
1788  * This also bypasses the usual "convert-to-git" dance, and that is on
1789  * purpose. We could write a streaming version of the converting
1790  * functions and insert that before feeding the data to fast-import
1791  * (or equivalent in-core API described above). However, that is
1792  * somewhat complicated, as we do not know the size of the filter
1793  * result, which we need to know beforehand when writing a git object.
1794  * Since the primary motivation for trying to stream from the working
1795  * tree file and to avoid mmaping it in core is to deal with large
1796  * binary blobs, they generally do not want to get any conversion, and
1797  * callers should avoid this code path when filters are requested.
1798  */
1799 static int index_stream(struct object_id *oid, int fd, size_t size,
1800                         enum object_type type, const char *path,
1801                         unsigned flags)
1802 {
1803         return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1804 }
1805
1806 int index_fd(struct object_id *oid, int fd, struct stat *st,
1807              enum object_type type, const char *path, unsigned flags)
1808 {
1809         int ret;
1810
1811         /*
1812          * Call xsize_t() only when needed to avoid potentially unnecessary
1813          * die() for large files.
1814          */
1815         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1816                 ret = index_stream_convert_blob(oid, fd, path, flags);
1817         else if (!S_ISREG(st->st_mode))
1818                 ret = index_pipe(oid, fd, type, path, flags);
1819         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1820                  (path && would_convert_to_git(&the_index, path)))
1821                 ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1822                                  flags);
1823         else
1824                 ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1825                                    flags);
1826         close(fd);
1827         return ret;
1828 }
1829
1830 int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1831 {
1832         int fd;
1833         struct strbuf sb = STRBUF_INIT;
1834         int rc = 0;
1835
1836         switch (st->st_mode & S_IFMT) {
1837         case S_IFREG:
1838                 fd = open(path, O_RDONLY);
1839                 if (fd < 0)
1840                         return error_errno("open(\"%s\")", path);
1841                 if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1842                         return error("%s: failed to insert into database",
1843                                      path);
1844                 break;
1845         case S_IFLNK:
1846                 if (strbuf_readlink(&sb, path, st->st_size))
1847                         return error_errno("readlink(\"%s\")", path);
1848                 if (!(flags & HASH_WRITE_OBJECT))
1849                         hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1850                 else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1851                         rc = error("%s: failed to insert into database", path);
1852                 strbuf_release(&sb);
1853                 break;
1854         case S_IFDIR:
1855                 return resolve_gitlink_ref(path, "HEAD", oid);
1856         default:
1857                 return error("%s: unsupported file type", path);
1858         }
1859         return rc;
1860 }
1861
1862 int read_pack_header(int fd, struct pack_header *header)
1863 {
1864         if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1865                 /* "eof before pack header was fully read" */
1866                 return PH_ERROR_EOF;
1867
1868         if (header->hdr_signature != htonl(PACK_SIGNATURE))
1869                 /* "protocol error (pack signature mismatch detected)" */
1870                 return PH_ERROR_PACK_SIGNATURE;
1871         if (!pack_version_ok(header->hdr_version))
1872                 /* "protocol error (pack version unsupported)" */
1873                 return PH_ERROR_PROTOCOL;
1874         return 0;
1875 }
1876
1877 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1878 {
1879         enum object_type type = sha1_object_info(sha1, NULL);
1880         if (type < 0)
1881                 die("%s is not a valid object", sha1_to_hex(sha1));
1882         if (type != expect)
1883                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1884                     typename(expect));
1885 }
1886
1887 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1888                                 struct strbuf *path,
1889                                 each_loose_object_fn obj_cb,
1890                                 each_loose_cruft_fn cruft_cb,
1891                                 each_loose_subdir_fn subdir_cb,
1892                                 void *data)
1893 {
1894         size_t origlen, baselen;
1895         DIR *dir;
1896         struct dirent *de;
1897         int r = 0;
1898         struct object_id oid;
1899
1900         if (subdir_nr > 0xff)
1901                 BUG("invalid loose object subdirectory: %x", subdir_nr);
1902
1903         origlen = path->len;
1904         strbuf_complete(path, '/');
1905         strbuf_addf(path, "%02x", subdir_nr);
1906
1907         dir = opendir(path->buf);
1908         if (!dir) {
1909                 if (errno != ENOENT)
1910                         r = error_errno("unable to open %s", path->buf);
1911                 strbuf_setlen(path, origlen);
1912                 return r;
1913         }
1914
1915         oid.hash[0] = subdir_nr;
1916         strbuf_addch(path, '/');
1917         baselen = path->len;
1918
1919         while ((de = readdir(dir))) {
1920                 size_t namelen;
1921                 if (is_dot_or_dotdot(de->d_name))
1922                         continue;
1923
1924                 namelen = strlen(de->d_name);
1925                 strbuf_setlen(path, baselen);
1926                 strbuf_add(path, de->d_name, namelen);
1927                 if (namelen == GIT_SHA1_HEXSZ - 2 &&
1928                     !hex_to_bytes(oid.hash + 1, de->d_name,
1929                                   GIT_SHA1_RAWSZ - 1)) {
1930                         if (obj_cb) {
1931                                 r = obj_cb(&oid, path->buf, data);
1932                                 if (r)
1933                                         break;
1934                         }
1935                         continue;
1936                 }
1937
1938                 if (cruft_cb) {
1939                         r = cruft_cb(de->d_name, path->buf, data);
1940                         if (r)
1941                                 break;
1942                 }
1943         }
1944         closedir(dir);
1945
1946         strbuf_setlen(path, baselen - 1);
1947         if (!r && subdir_cb)
1948                 r = subdir_cb(subdir_nr, path->buf, data);
1949
1950         strbuf_setlen(path, origlen);
1951
1952         return r;
1953 }
1954
1955 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
1956                             each_loose_object_fn obj_cb,
1957                             each_loose_cruft_fn cruft_cb,
1958                             each_loose_subdir_fn subdir_cb,
1959                             void *data)
1960 {
1961         int r = 0;
1962         int i;
1963
1964         for (i = 0; i < 256; i++) {
1965                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
1966                                                 subdir_cb, data);
1967                 if (r)
1968                         break;
1969         }
1970
1971         return r;
1972 }
1973
1974 int for_each_loose_file_in_objdir(const char *path,
1975                                   each_loose_object_fn obj_cb,
1976                                   each_loose_cruft_fn cruft_cb,
1977                                   each_loose_subdir_fn subdir_cb,
1978                                   void *data)
1979 {
1980         struct strbuf buf = STRBUF_INIT;
1981         int r;
1982
1983         strbuf_addstr(&buf, path);
1984         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
1985                                               subdir_cb, data);
1986         strbuf_release(&buf);
1987
1988         return r;
1989 }
1990
1991 struct loose_alt_odb_data {
1992         each_loose_object_fn *cb;
1993         void *data;
1994 };
1995
1996 static int loose_from_alt_odb(struct alternate_object_database *alt,
1997                               void *vdata)
1998 {
1999         struct loose_alt_odb_data *data = vdata;
2000         struct strbuf buf = STRBUF_INIT;
2001         int r;
2002
2003         strbuf_addstr(&buf, alt->path);
2004         r = for_each_loose_file_in_objdir_buf(&buf,
2005                                               data->cb, NULL, NULL,
2006                                               data->data);
2007         strbuf_release(&buf);
2008         return r;
2009 }
2010
2011 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2012 {
2013         struct loose_alt_odb_data alt;
2014         int r;
2015
2016         r = for_each_loose_file_in_objdir(get_object_directory(),
2017                                           cb, NULL, NULL, data);
2018         if (r)
2019                 return r;
2020
2021         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2022                 return 0;
2023
2024         alt.cb = cb;
2025         alt.data = data;
2026         return foreach_alt_odb(loose_from_alt_odb, &alt);
2027 }
2028
2029 static int check_stream_sha1(git_zstream *stream,
2030                              const char *hdr,
2031                              unsigned long size,
2032                              const char *path,
2033                              const unsigned char *expected_sha1)
2034 {
2035         git_SHA_CTX c;
2036         unsigned char real_sha1[GIT_MAX_RAWSZ];
2037         unsigned char buf[4096];
2038         unsigned long total_read;
2039         int status = Z_OK;
2040
2041         git_SHA1_Init(&c);
2042         git_SHA1_Update(&c, hdr, stream->total_out);
2043
2044         /*
2045          * We already read some bytes into hdr, but the ones up to the NUL
2046          * do not count against the object's content size.
2047          */
2048         total_read = stream->total_out - strlen(hdr) - 1;
2049
2050         /*
2051          * This size comparison must be "<=" to read the final zlib packets;
2052          * see the comment in unpack_sha1_rest for details.
2053          */
2054         while (total_read <= size &&
2055                (status == Z_OK || status == Z_BUF_ERROR)) {
2056                 stream->next_out = buf;
2057                 stream->avail_out = sizeof(buf);
2058                 if (size - total_read < stream->avail_out)
2059                         stream->avail_out = size - total_read;
2060                 status = git_inflate(stream, Z_FINISH);
2061                 git_SHA1_Update(&c, buf, stream->next_out - buf);
2062                 total_read += stream->next_out - buf;
2063         }
2064         git_inflate_end(stream);
2065
2066         if (status != Z_STREAM_END) {
2067                 error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2068                 return -1;
2069         }
2070         if (stream->avail_in) {
2071                 error("garbage at end of loose object '%s'",
2072                       sha1_to_hex(expected_sha1));
2073                 return -1;
2074         }
2075
2076         git_SHA1_Final(real_sha1, &c);
2077         if (hashcmp(expected_sha1, real_sha1)) {
2078                 error("sha1 mismatch for %s (expected %s)", path,
2079                       sha1_to_hex(expected_sha1));
2080                 return -1;
2081         }
2082
2083         return 0;
2084 }
2085
2086 int read_loose_object(const char *path,
2087                       const unsigned char *expected_sha1,
2088                       enum object_type *type,
2089                       unsigned long *size,
2090                       void **contents)
2091 {
2092         int ret = -1;
2093         void *map = NULL;
2094         unsigned long mapsize;
2095         git_zstream stream;
2096         char hdr[32];
2097
2098         *contents = NULL;
2099
2100         map = map_sha1_file_1(path, NULL, &mapsize);
2101         if (!map) {
2102                 error_errno("unable to mmap %s", path);
2103                 goto out;
2104         }
2105
2106         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2107                 error("unable to unpack header of %s", path);
2108                 goto out;
2109         }
2110
2111         *type = parse_sha1_header(hdr, size);
2112         if (*type < 0) {
2113                 error("unable to parse header of %s", path);
2114                 git_inflate_end(&stream);
2115                 goto out;
2116         }
2117
2118         if (*type == OBJ_BLOB) {
2119                 if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2120                         goto out;
2121         } else {
2122                 *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2123                 if (!*contents) {
2124                         error("unable to unpack contents of %s", path);
2125                         git_inflate_end(&stream);
2126                         goto out;
2127                 }
2128                 if (check_sha1_signature(expected_sha1, *contents,
2129                                          *size, typename(*type))) {
2130                         error("sha1 mismatch for %s (expected %s)", path,
2131                               sha1_to_hex(expected_sha1));
2132                         free(*contents);
2133                         goto out;
2134                 }
2135         }
2136
2137         ret = 0; /* everything checks out */
2138
2139 out:
2140         if (map)
2141                 munmap(map, mapsize);
2142         return ret;
2143 }