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