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