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