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 "repository.h"
  26 #include "streaming.h"
  27 #include "dir.h"
  28 #include "list.h"
  29 #include "mergesort.h"
  30 #include "quote.h"
  31 #include "packfile.h"
  32 #include "fetch-object.h"
  33 #include "object-store.h"
  34
  35 const unsigned char null_sha1[GIT_MAX_RAWSZ];
  36 const struct object_id null_oid;
  37 const struct object_id empty_tree_oid = {
  38         EMPTY_TREE_SHA1_BIN_LITERAL
  39 };
  40 const struct object_id empty_blob_oid = {
  41         EMPTY_BLOB_SHA1_BIN_LITERAL
  42 };
  43
  44 static void git_hash_sha1_init(void *ctx)
  45 {
  46         git_SHA1_Init((git_SHA_CTX *)ctx);
  47 }
  48
  49 static void git_hash_sha1_update(void *ctx, const void *data, size_t len)
  50 {
  51         git_SHA1_Update((git_SHA_CTX *)ctx, data, len);
  52 }
  53
  54 static void git_hash_sha1_final(unsigned char *hash, void *ctx)
  55 {
  56         git_SHA1_Final(hash, (git_SHA_CTX *)ctx);
  57 }
  58
  59 static void git_hash_unknown_init(void *ctx)
  60 {
  61         die("trying to init unknown hash");
  62 }
  63
  64 static void git_hash_unknown_update(void *ctx, const void *data, size_t len)
  65 {
  66         die("trying to update unknown hash");
  67 }
  68
  69 static void git_hash_unknown_final(unsigned char *hash, void *ctx)
  70 {
  71         die("trying to finalize unknown hash");
  72 }
  73
  74 const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
  75         {
  76                 NULL,
  77                 0x00000000,
  78                 0,
  79                 0,
  80                 0,
  81                 git_hash_unknown_init,
  82                 git_hash_unknown_update,
  83                 git_hash_unknown_final,
  84                 NULL,
  85                 NULL,
  86         },
  87         {
  88                 "sha-1",
  89                 /* "sha1", big-endian */
  90                 0x73686131,
  91                 sizeof(git_SHA_CTX),
  92                 GIT_SHA1_RAWSZ,
  93                 GIT_SHA1_HEXSZ,
  94                 git_hash_sha1_init,
  95                 git_hash_sha1_update,
  96                 git_hash_sha1_final,
  97                 &empty_tree_oid,
  98                 &empty_blob_oid,
  99         },
 100 };
 101
 102 /*
 103  * This is meant to hold a *small* number of objects that you would
 104  * want read_sha1_file() to be able to return, but yet you do not want
 105  * to write them into the object store (e.g. a browse-only
 106  * application).
 107  */
 108 static struct cached_object {
 109         unsigned char sha1[20];
 110         enum object_type type;
 111         void *buf;
 112         unsigned long size;
 113 } *cached_objects;
 114 static int cached_object_nr, cached_object_alloc;
 115
 116 static struct cached_object empty_tree = {
 117         EMPTY_TREE_SHA1_BIN_LITERAL,
 118         OBJ_TREE,
 119         "",
 120         0
 121 };
 122
 123 static struct cached_object *find_cached_object(const unsigned char *sha1)
 124 {
 125         int i;
 126         struct cached_object *co = cached_objects;
 127
 128         for (i = 0; i < cached_object_nr; i++, co++) {
 129                 if (!hashcmp(co->sha1, sha1))
 130                         return co;
 131         }
 132         if (!hashcmp(sha1, empty_tree.sha1))
 133                 return &empty_tree;
 134         return NULL;
 135 }
 136
 137
 138 static int get_conv_flags(unsigned flags)
 139 {
 140         if (flags & HASH_RENORMALIZE)
 141                 return CONV_EOL_RENORMALIZE;
 142         else if (flags & HASH_WRITE_OBJECT)
 143           return global_conv_flags_eol;
 144         else
 145                 return 0;
 146 }
 147
 148
 149 int mkdir_in_gitdir(const char *path)
 150 {
 151         if (mkdir(path, 0777)) {
 152                 int saved_errno = errno;
 153                 struct stat st;
 154                 struct strbuf sb = STRBUF_INIT;
 155
 156                 if (errno != EEXIST)
 157                         return -1;
 158                 /*
 159                  * Are we looking at a path in a symlinked worktree
 160                  * whose original repository does not yet have it?
 161                  * e.g. .git/rr-cache pointing at its original
 162                  * repository in which the user hasn't performed any
 163                  * conflict resolution yet?
 164                  */
 165                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 166                     strbuf_readlink(&sb, path, st.st_size) ||
 167                     !is_absolute_path(sb.buf) ||
 168                     mkdir(sb.buf, 0777)) {
 169                         strbuf_release(&sb);
 170                         errno = saved_errno;
 171                         return -1;
 172                 }
 173                 strbuf_release(&sb);
 174         }
 175         return adjust_shared_perm(path);
 176 }
 177
 178 enum scld_error safe_create_leading_directories(char *path)
 179 {
 180         char *next_component = path + offset_1st_component(path);
 181         enum scld_error ret = SCLD_OK;
 182
 183         while (ret == SCLD_OK && next_component) {
 184                 struct stat st;
 185                 char *slash = next_component, slash_character;
 186
 187                 while (*slash && !is_dir_sep(*slash))
 188                         slash++;
 189
 190                 if (!*slash)
 191                         break;
 192
 193                 next_component = slash + 1;
 194                 while (is_dir_sep(*next_component))
 195                         next_component++;
 196                 if (!*next_component)
 197                         break;
 198
 199                 slash_character = *slash;
 200                 *slash = '\0';
 201                 if (!stat(path, &st)) {
 202                         /* path exists */
 203                         if (!S_ISDIR(st.st_mode)) {
 204                                 errno = ENOTDIR;
 205                                 ret = SCLD_EXISTS;
 206                         }
 207                 } else if (mkdir(path, 0777)) {
 208                         if (errno == EEXIST &&
 209                             !stat(path, &st) && S_ISDIR(st.st_mode))
 210                                 ; /* somebody created it since we checked */
 211                         else if (errno == ENOENT)
 212                                 /*
 213                                  * Either mkdir() failed because
 214                                  * somebody just pruned the containing
 215                                  * directory, or stat() failed because
 216                                  * the file that was in our way was
 217                                  * just removed.  Either way, inform
 218                                  * the caller that it might be worth
 219                                  * trying again:
 220                                  */
 221                                 ret = SCLD_VANISHED;
 222                         else
 223                                 ret = SCLD_FAILED;
 224                 } else if (adjust_shared_perm(path)) {
 225                         ret = SCLD_PERMS;
 226                 }
 227                 *slash = slash_character;
 228         }
 229         return ret;
 230 }
 231
 232 enum scld_error safe_create_leading_directories_const(const char *path)
 233 {
 234         int save_errno;
 235         /* path points to cache entries, so xstrdup before messing with it */
 236         char *buf = xstrdup(path);
 237         enum scld_error result = safe_create_leading_directories(buf);
 238
 239         save_errno = errno;
 240         free(buf);
 241         errno = save_errno;
 242         return result;
 243 }
 244
 245 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 246 {
 247         /*
 248          * The number of times we will try to remove empty directories
 249          * in the way of path. This is only 1 because if another
 250          * process is racily creating directories that conflict with
 251          * us, we don't want to fight against them.
 252          */
 253         int remove_directories_remaining = 1;
 254
 255         /*
 256          * The number of times that we will try to create the
 257          * directories containing path. We are willing to attempt this
 258          * more than once, because another process could be trying to
 259          * clean up empty directories at the same time as we are
 260          * trying to create them.
 261          */
 262         int create_directories_remaining = 3;
 263
 264         /* A scratch copy of path, filled lazily if we need it: */
 265         struct strbuf path_copy = STRBUF_INIT;
 266
 267         int ret, save_errno;
 268
 269         /* Sanity check: */
 270         assert(*path);
 271
 272 retry_fn:
 273         ret = fn(path, cb);
 274         save_errno = errno;
 275         if (!ret)
 276                 goto out;
 277
 278         if (errno == EISDIR && remove_directories_remaining-- > 0) {
 279                 /*
 280                  * A directory is in the way. Maybe it is empty; try
 281                  * to remove it:
 282                  */
 283                 if (!path_copy.len)
 284                         strbuf_addstr(&path_copy, path);
 285
 286                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 287                         goto retry_fn;
 288         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 289                 /*
 290                  * Maybe the containing directory didn't exist, or
 291                  * maybe it was just deleted by a process that is
 292                  * racing with us to clean up empty directories. Try
 293                  * to create it:
 294                  */
 295                 enum scld_error scld_result;
 296
 297                 if (!path_copy.len)
 298                         strbuf_addstr(&path_copy, path);
 299
 300                 do {
 301                         scld_result = safe_create_leading_directories(path_copy.buf);
 302                         if (scld_result == SCLD_OK)
 303                                 goto retry_fn;
 304                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 305         }
 306
 307 out:
 308         strbuf_release(&path_copy);
 309         errno = save_errno;
 310         return ret;
 311 }
 312
 313 static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 314 {
 315         int i;
 316         for (i = 0; i < 20; i++) {
 317                 static char hex[] = "0123456789abcdef";
 318                 unsigned int val = sha1[i];
 319                 strbuf_addch(buf, hex[val >> 4]);
 320                 strbuf_addch(buf, hex[val & 0xf]);
 321                 if (!i)
 322                         strbuf_addch(buf, '/');
 323         }
 324 }
 325
 326 void sha1_file_name_the_repository(struct strbuf *buf, const unsigned char *sha1)
 327 {
 328         strbuf_addstr(buf, get_object_directory());
 329         strbuf_addch(buf, '/');
 330         fill_sha1_path(buf, sha1);
 331 }
 332
 333 struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 334 {
 335         strbuf_setlen(&alt->scratch, alt->base_len);
 336         return &alt->scratch;
 337 }
 338
 339 static const char *alt_sha1_path(struct alternate_object_database *alt,
 340                                  const unsigned char *sha1)
 341 {
 342         struct strbuf *buf = alt_scratch_buf(alt);
 343         fill_sha1_path(buf, sha1);
 344         return buf->buf;
 345 }
 346
 347 /*
 348  * Return non-zero iff the path is usable as an alternate object database.
 349  */
 350 static int alt_odb_usable(struct raw_object_store *o,
 351                           struct strbuf *path,
 352                           const char *normalized_objdir)
 353 {
 354         struct alternate_object_database *alt;
 355
 356         /* Detect cases where alternate disappeared */
 357         if (!is_directory(path->buf)) {
 358                 error("object directory %s does not exist; "
 359                       "check .git/objects/info/alternates.",
 360                       path->buf);
 361                 return 0;
 362         }
 363
 364         /*
 365          * Prevent the common mistake of listing the same
 366          * thing twice, or object directory itself.
 367          */
 368         for (alt = o->alt_odb_list; alt; alt = alt->next) {
 369                 if (!fspathcmp(path->buf, alt->path))
 370                         return 0;
 371         }
 372         if (!fspathcmp(path->buf, normalized_objdir))
 373                 return 0;
 374
 375         return 1;
 376 }
 377
 378 /*
 379  * Prepare alternate object database registry.
 380  *
 381  * The variable alt_odb_list points at the list of struct
 382  * alternate_object_database.  The elements on this list come from
 383  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 384  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 385  * whose contents is similar to that environment variable but can be
 386  * LF separated.  Its base points at a statically allocated buffer that
 387  * contains "/the/directory/corresponding/to/.git/objects/...", while
 388  * its name points just after the slash at the end of ".git/objects/"
 389  * in the example above, and has enough space to hold 40-byte hex
 390  * SHA1, an extra slash for the first level indirection, and the
 391  * terminating NUL.
 392  */
 393 static void read_info_alternates(struct repository *r,
 394                                  const char *relative_base,
 395                                  int depth);
 396 static int link_alt_odb_entry(struct repository *r, const char *entry,
 397         const char *relative_base, int depth, const char *normalized_objdir)
 398 {
 399         struct alternate_object_database *ent;
 400         struct strbuf pathbuf = STRBUF_INIT;
 401
 402         if (!is_absolute_path(entry) && relative_base) {
 403                 strbuf_realpath(&pathbuf, relative_base, 1);
 404                 strbuf_addch(&pathbuf, '/');
 405         }
 406         strbuf_addstr(&pathbuf, entry);
 407
 408         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 409                 error("unable to normalize alternate object path: %s",
 410                       pathbuf.buf);
 411                 strbuf_release(&pathbuf);
 412                 return -1;
 413         }
 414
 415         /*
 416          * The trailing slash after the directory name is given by
 417          * this function at the end. Remove duplicates.
 418          */
 419         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 420                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
 421
 422         if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir)) {
 423                 strbuf_release(&pathbuf);
 424                 return -1;
 425         }
 426
 427         ent = alloc_alt_odb(pathbuf.buf);
 428
 429         /* add the alternate entry */
 430         *r->objects->alt_odb_tail = ent;
 431         r->objects->alt_odb_tail = &(ent->next);
 432         ent->next = NULL;
 433
 434         /* recursively add alternates */
 435         read_info_alternates(r, pathbuf.buf, depth + 1);
 436
 437         strbuf_release(&pathbuf);
 438         return 0;
 439 }
 440
 441 static const char *parse_alt_odb_entry(const char *string,
 442                                        int sep,
 443                                        struct strbuf *out)
 444 {
 445         const char *end;
 446
 447         strbuf_reset(out);
 448
 449         if (*string == '#') {
 450                 /* comment; consume up to next separator */
 451                 end = strchrnul(string, sep);
 452         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 453                 /*
 454                  * quoted path; unquote_c_style has copied the
 455                  * data for us and set "end". Broken quoting (e.g.,
 456                  * an entry that doesn't end with a quote) falls
 457                  * back to the unquoted case below.
 458                  */
 459         } else {
 460                 /* normal, unquoted path */
 461                 end = strchrnul(string, sep);
 462                 strbuf_add(out, string, end - string);
 463         }
 464
 465         if (*end)
 466                 end++;
 467         return end;
 468 }
 469
 470 static void link_alt_odb_entries(struct repository *r, const char *alt,
 471                                  int sep, const char *relative_base, int depth)
 472 {
 473         struct strbuf objdirbuf = STRBUF_INIT;
 474         struct strbuf entry = STRBUF_INIT;
 475
 476         if (!alt || !*alt)
 477                 return;
 478
 479         if (depth > 5) {
 480                 error("%s: ignoring alternate object stores, nesting too deep.",
 481                                 relative_base);
 482                 return;
 483         }
 484
 485         strbuf_add_absolute_path(&objdirbuf, r->objects->objectdir);
 486         if (strbuf_normalize_path(&objdirbuf) < 0)
 487                 die("unable to normalize object directory: %s",
 488                     objdirbuf.buf);
 489
 490         while (*alt) {
 491                 alt = parse_alt_odb_entry(alt, sep, &entry);
 492                 if (!entry.len)
 493                         continue;
 494                 link_alt_odb_entry(r, entry.buf,
 495                                    relative_base, depth, objdirbuf.buf);
 496         }
 497         strbuf_release(&entry);
 498         strbuf_release(&objdirbuf);
 499 }
 500
 501 static void read_info_alternates(struct repository *r,
 502                                  const char *relative_base,
 503                                  int depth)
 504 {
 505         char *path;
 506         struct strbuf buf = STRBUF_INIT;
 507
 508         path = xstrfmt("%s/info/alternates", relative_base);
 509         if (strbuf_read_file(&buf, path, 1024) < 0) {
 510                 warn_on_fopen_errors(path);
 511                 free(path);
 512                 return;
 513         }
 514
 515         link_alt_odb_entries(r, buf.buf, '\n', relative_base, depth);
 516         strbuf_release(&buf);
 517         free(path);
 518 }
 519
 520 struct alternate_object_database *alloc_alt_odb(const char *dir)
 521 {
 522         struct alternate_object_database *ent;
 523
 524         FLEX_ALLOC_STR(ent, path, dir);
 525         strbuf_init(&ent->scratch, 0);
 526         strbuf_addf(&ent->scratch, "%s/", dir);
 527         ent->base_len = ent->scratch.len;
 528
 529         return ent;
 530 }
 531
 532 void add_to_alternates_file(const char *reference)
 533 {
 534         struct lock_file lock = LOCK_INIT;
 535         char *alts = git_pathdup("objects/info/alternates");
 536         FILE *in, *out;
 537         int found = 0;
 538
 539         hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 540         out = fdopen_lock_file(&lock, "w");
 541         if (!out)
 542                 die_errno("unable to fdopen alternates lockfile");
 543
 544         in = fopen(alts, "r");
 545         if (in) {
 546                 struct strbuf line = STRBUF_INIT;
 547
 548                 while (strbuf_getline(&line, in) != EOF) {
 549                         if (!strcmp(reference, line.buf)) {
 550                                 found = 1;
 551                                 break;
 552                         }
 553                         fprintf_or_die(out, "%s\n", line.buf);
 554                 }
 555
 556                 strbuf_release(&line);
 557                 fclose(in);
 558         }
 559         else if (errno != ENOENT)
 560                 die_errno("unable to read alternates file");
 561
 562         if (found) {
 563                 rollback_lock_file(&lock);
 564         } else {
 565                 fprintf_or_die(out, "%s\n", reference);
 566                 if (commit_lock_file(&lock))
 567                         die_errno("unable to move new alternates file into place");
 568                 if (the_repository->objects->alt_odb_tail)
 569                         link_alt_odb_entries(the_repository, reference,
 570                                              '\n', NULL, 0);
 571         }
 572         free(alts);
 573 }
 574
 575 void add_to_alternates_memory(const char *reference)
 576 {
 577         /*
 578          * Make sure alternates are initialized, or else our entry may be
 579          * overwritten when they are.
 580          */
 581         prepare_alt_odb(the_repository);
 582
 583         link_alt_odb_entries(the_repository, reference,
 584                              '\n', NULL, 0);
 585 }
 586
 587 /*
 588  * Compute the exact path an alternate is at and returns it. In case of
 589  * error NULL is returned and the human readable error is added to `err`
 590  * `path` may be relative and should point to $GITDIR.
 591  * `err` must not be null.
 592  */
 593 char *compute_alternate_path(const char *path, struct strbuf *err)
 594 {
 595         char *ref_git = NULL;
 596         const char *repo, *ref_git_s;
 597         int seen_error = 0;
 598
 599         ref_git_s = real_path_if_valid(path);
 600         if (!ref_git_s) {
 601                 seen_error = 1;
 602                 strbuf_addf(err, _("path '%s' does not exist"), path);
 603                 goto out;
 604         } else
 605                 /*
 606                  * Beware: read_gitfile(), real_path() and mkpath()
 607                  * return static buffer
 608                  */
 609                 ref_git = xstrdup(ref_git_s);
 610
 611         repo = read_gitfile(ref_git);
 612         if (!repo)
 613                 repo = read_gitfile(mkpath("%s/.git", ref_git));
 614         if (repo) {
 615                 free(ref_git);
 616                 ref_git = xstrdup(repo);
 617         }
 618
 619         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 620                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
 621                 free(ref_git);
 622                 ref_git = ref_git_git;
 623         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 624                 struct strbuf sb = STRBUF_INIT;
 625                 seen_error = 1;
 626                 if (get_common_dir(&sb, ref_git)) {
 627                         strbuf_addf(err,
 628                                     _("reference repository '%s' as a linked "
 629                                       "checkout is not supported yet."),
 630                                     path);
 631                         goto out;
 632                 }
 633
 634                 strbuf_addf(err, _("reference repository '%s' is not a "
 635                                         "local repository."), path);
 636                 goto out;
 637         }
 638
 639         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 640                 strbuf_addf(err, _("reference repository '%s' is shallow"),
 641                             path);
 642                 seen_error = 1;
 643                 goto out;
 644         }
 645
 646         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 647                 strbuf_addf(err,
 648                             _("reference repository '%s' is grafted"),
 649                             path);
 650                 seen_error = 1;
 651                 goto out;
 652         }
 653
 654 out:
 655         if (seen_error) {
 656                 FREE_AND_NULL(ref_git);
 657         }
 658
 659         return ref_git;
 660 }
 661
 662 int foreach_alt_odb(alt_odb_fn fn, void *cb)
 663 {
 664         struct alternate_object_database *ent;
 665         int r = 0;
 666
 667         prepare_alt_odb(the_repository);
 668         for (ent = the_repository->objects->alt_odb_list; ent; ent = ent->next) {
 669                 r = fn(ent, cb);
 670                 if (r)
 671                         break;
 672         }
 673         return r;
 674 }
 675
 676 void prepare_alt_odb(struct repository *r)
 677 {
 678         if (r->objects->alt_odb_tail)
 679                 return;
 680
 681         r->objects->alt_odb_tail = &r->objects->alt_odb_list;
 682         link_alt_odb_entries(r, r->objects->alternate_db, PATH_SEP, NULL, 0);
 683
 684         read_info_alternates(r, r->objects->objectdir, 0);
 685 }
 686
 687 /* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 688 static int freshen_file(const char *fn)
 689 {
 690         struct utimbuf t;
 691         t.actime = t.modtime = time(NULL);
 692         return !utime(fn, &t);
 693 }
 694
 695 /*
 696  * All of the check_and_freshen functions return 1 if the file exists and was
 697  * freshened (if freshening was requested), 0 otherwise. If they return
 698  * 0, you should not assume that it is safe to skip a write of the object (it
 699  * either does not exist on disk, or has a stale mtime and may be subject to
 700  * pruning).
 701  */
 702 int check_and_freshen_file(const char *fn, int freshen)
 703 {
 704         if (access(fn, F_OK))
 705                 return 0;
 706         if (freshen && !freshen_file(fn))
 707                 return 0;
 708         return 1;
 709 }
 710
 711 static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 712 {
 713         static struct strbuf buf = STRBUF_INIT;
 714
 715         strbuf_reset(&buf);
 716         sha1_file_name(the_repository, &buf, sha1);
 717
 718         return check_and_freshen_file(buf.buf, freshen);
 719 }
 720
 721 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 722 {
 723         struct alternate_object_database *alt;
 724         prepare_alt_odb(the_repository);
 725         for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 726                 const char *path = alt_sha1_path(alt, sha1);
 727                 if (check_and_freshen_file(path, freshen))
 728                         return 1;
 729         }
 730         return 0;
 731 }
 732
 733 static int check_and_freshen(const unsigned char *sha1, int freshen)
 734 {
 735         return check_and_freshen_local(sha1, freshen) ||
 736                check_and_freshen_nonlocal(sha1, freshen);
 737 }
 738
 739 int has_loose_object_nonlocal(const unsigned char *sha1)
 740 {
 741         return check_and_freshen_nonlocal(sha1, 0);
 742 }
 743
 744 static int has_loose_object(const unsigned char *sha1)
 745 {
 746         return check_and_freshen(sha1, 0);
 747 }
 748
 749 static void mmap_limit_check(size_t length)
 750 {
 751         static size_t limit = 0;
 752         if (!limit) {
 753                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 754                 if (!limit)
 755                         limit = SIZE_MAX;
 756         }
 757         if (length > limit)
 758                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 759                     (uintmax_t)length, (uintmax_t)limit);
 760 }
 761
 762 void *xmmap_gently(void *start, size_t length,
 763                   int prot, int flags, int fd, off_t offset)
 764 {
 765         void *ret;
 766
 767         mmap_limit_check(length);
 768         ret = mmap(start, length, prot, flags, fd, offset);
 769         if (ret == MAP_FAILED) {
 770                 if (!length)
 771                         return NULL;
 772                 release_pack_memory(length);
 773                 ret = mmap(start, length, prot, flags, fd, offset);
 774         }
 775         return ret;
 776 }
 777
 778 void *xmmap(void *start, size_t length,
 779         int prot, int flags, int fd, off_t offset)
 780 {
 781         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 782         if (ret == MAP_FAILED)
 783                 die_errno("mmap failed");
 784         return ret;
 785 }
 786
 787 /*
 788  * With an in-core object data in "map", rehash it to make sure the
 789  * object name actually matches "sha1" to detect object corruption.
 790  * With "map" == NULL, try reading the object named with "sha1" using
 791  * the streaming interface and rehash it to do the same.
 792  */
 793 int check_sha1_signature(const unsigned char *sha1, void *map,
 794                          unsigned long size, const char *type)
 795 {
 796         unsigned char real_sha1[20];
 797         enum object_type obj_type;
 798         struct git_istream *st;
 799         git_SHA_CTX c;
 800         char hdr[32];
 801         int hdrlen;
 802
 803         if (map) {
 804                 hash_sha1_file(map, size, type, real_sha1);
 805                 return hashcmp(sha1, real_sha1) ? -1 : 0;
 806         }
 807
 808         st = open_istream(sha1, &obj_type, &size, NULL);
 809         if (!st)
 810                 return -1;
 811
 812         /* Generate the header */
 813         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 814
 815         /* Sha1.. */
 816         git_SHA1_Init(&c);
 817         git_SHA1_Update(&c, hdr, hdrlen);
 818         for (;;) {
 819                 char buf[1024 * 16];
 820                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
 821
 822                 if (readlen < 0) {
 823                         close_istream(st);
 824                         return -1;
 825                 }
 826                 if (!readlen)
 827                         break;
 828                 git_SHA1_Update(&c, buf, readlen);
 829         }
 830         git_SHA1_Final(real_sha1, &c);
 831         close_istream(st);
 832         return hashcmp(sha1, real_sha1) ? -1 : 0;
 833 }
 834
 835 int git_open_cloexec(const char *name, int flags)
 836 {
 837         int fd;
 838         static int o_cloexec = O_CLOEXEC;
 839
 840         fd = open(name, flags | o_cloexec);
 841         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 842                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
 843                 o_cloexec &= ~O_CLOEXEC;
 844                 fd = open(name, flags | o_cloexec);
 845         }
 846
 847 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 848         {
 849                 static int fd_cloexec = FD_CLOEXEC;
 850
 851                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
 852                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 853                         int flags = fcntl(fd, F_GETFD);
 854                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 855                                 fd_cloexec = 0;
 856                 }
 857         }
 858 #endif
 859         return fd;
 860 }
 861
 862 /*
 863  * Find "sha1" as a loose object in the local repository or in an alternate.
 864  * Returns 0 on success, negative on failure.
 865  *
 866  * The "path" out-parameter will give the path of the object we found (if any).
 867  * Note that it may point to static storage and is only valid until another
 868  * call to sha1_file_name(), etc.
 869  */
 870 #define stat_sha1_file(r, s, st, p) stat_sha1_file_##r(s, st, p)
 871 static int stat_sha1_file_the_repository(const unsigned char *sha1,
 872                                          struct stat *st, const char **path)
 873 {
 874         struct alternate_object_database *alt;
 875         static struct strbuf buf = STRBUF_INIT;
 876
 877         strbuf_reset(&buf);
 878         sha1_file_name(the_repository, &buf, sha1);
 879         *path = buf.buf;
 880
 881         if (!lstat(*path, st))
 882                 return 0;
 883
 884         prepare_alt_odb(the_repository);
 885         errno = ENOENT;
 886         for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 887                 *path = alt_sha1_path(alt, sha1);
 888                 if (!lstat(*path, st))
 889                         return 0;
 890         }
 891
 892         return -1;
 893 }
 894
 895 /*
 896  * Like stat_sha1_file(), but actually open the object and return the
 897  * descriptor. See the caveats on the "path" parameter above.
 898  */
 899 static int open_sha1_file(const unsigned char *sha1, const char **path)
 900 {
 901         int fd;
 902         struct alternate_object_database *alt;
 903         int most_interesting_errno;
 904         static struct strbuf buf = STRBUF_INIT;
 905
 906         strbuf_reset(&buf);
 907         sha1_file_name(the_repository, &buf, sha1);
 908         *path = buf.buf;
 909
 910         fd = git_open(*path);
 911         if (fd >= 0)
 912                 return fd;
 913         most_interesting_errno = errno;
 914
 915         prepare_alt_odb(the_repository);
 916         for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 917                 *path = alt_sha1_path(alt, sha1);
 918                 fd = git_open(*path);
 919                 if (fd >= 0)
 920                         return fd;
 921                 if (most_interesting_errno == ENOENT)
 922                         most_interesting_errno = errno;
 923         }
 924         errno = most_interesting_errno;
 925         return -1;
 926 }
 927
 928 /*
 929  * Map the loose object at "path" if it is not NULL, or the path found by
 930  * searching for a loose object named "sha1".
 931  */
 932 static void *map_sha1_file_1(const char *path,
 933                              const unsigned char *sha1,
 934                              unsigned long *size)
 935 {
 936         void *map;
 937         int fd;
 938
 939         if (path)
 940                 fd = git_open(path);
 941         else
 942                 fd = open_sha1_file(sha1, &path);
 943         map = NULL;
 944         if (fd >= 0) {
 945                 struct stat st;
 946
 947                 if (!fstat(fd, &st)) {
 948                         *size = xsize_t(st.st_size);
 949                         if (!*size) {
 950                                 /* mmap() is forbidden on empty files */
 951                                 error("object file %s is empty", path);
 952                                 return NULL;
 953                         }
 954                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 955                 }
 956                 close(fd);
 957         }
 958         return map;
 959 }
 960
 961 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 962 {
 963         return map_sha1_file_1(NULL, sha1, size);
 964 }
 965
 966 static int unpack_sha1_short_header(git_zstream *stream,
 967                                     unsigned char *map, unsigned long mapsize,
 968                                     void *buffer, unsigned long bufsiz)
 969 {
 970         /* Get the data stream */
 971         memset(stream, 0, sizeof(*stream));
 972         stream->next_in = map;
 973         stream->avail_in = mapsize;
 974         stream->next_out = buffer;
 975         stream->avail_out = bufsiz;
 976
 977         git_inflate_init(stream);
 978         return git_inflate(stream, 0);
 979 }
 980
 981 int unpack_sha1_header(git_zstream *stream,
 982                        unsigned char *map, unsigned long mapsize,
 983                        void *buffer, unsigned long bufsiz)
 984 {
 985         int status = unpack_sha1_short_header(stream, map, mapsize,
 986                                               buffer, bufsiz);
 987
 988         if (status < Z_OK)
 989                 return status;
 990
 991         /* Make sure we have the terminating NUL */
 992         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 993                 return -1;
 994         return 0;
 995 }
 996
 997 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 998                                         unsigned long mapsize, void *buffer,
 999                                         unsigned long bufsiz, struct strbuf *header)
1000 {
1001         int status;
1002
1003         status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
1004         if (status < Z_OK)
1005                 return -1;
1006
1007         /*
1008          * Check if entire header is unpacked in the first iteration.
1009          */
1010         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1011                 return 0;
1012
1013         /*
1014          * buffer[0..bufsiz] was not large enough.  Copy the partial
1015          * result out to header, and then append the result of further
1016          * reading the stream.
1017          */
1018         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1019         stream->next_out = buffer;
1020         stream->avail_out = bufsiz;
1021
1022         do {
1023                 status = git_inflate(stream, 0);
1024                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1025                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1026                         return 0;
1027                 stream->next_out = buffer;
1028                 stream->avail_out = bufsiz;
1029         } while (status != Z_STREAM_END);
1030         return -1;
1031 }
1032
1033 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1034 {
1035         int bytes = strlen(buffer) + 1;
1036         unsigned char *buf = xmallocz(size);
1037         unsigned long n;
1038         int status = Z_OK;
1039
1040         n = stream->total_out - bytes;
1041         if (n > size)
1042                 n = size;
1043         memcpy(buf, (char *) buffer + bytes, n);
1044         bytes = n;
1045         if (bytes <= size) {
1046                 /*
1047                  * The above condition must be (bytes <= size), not
1048                  * (bytes < size).  In other words, even though we
1049                  * expect no more output and set avail_out to zero,
1050                  * the input zlib stream may have bytes that express
1051                  * "this concludes the stream", and we *do* want to
1052                  * eat that input.
1053                  *
1054                  * Otherwise we would not be able to test that we
1055                  * consumed all the input to reach the expected size;
1056                  * we also want to check that zlib tells us that all
1057                  * went well with status == Z_STREAM_END at the end.
1058                  */
1059                 stream->next_out = buf + bytes;
1060                 stream->avail_out = size - bytes;
1061                 while (status == Z_OK)
1062                         status = git_inflate(stream, Z_FINISH);
1063         }
1064         if (status == Z_STREAM_END && !stream->avail_in) {
1065                 git_inflate_end(stream);
1066                 return buf;
1067         }
1068
1069         if (status < 0)
1070                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1071         else if (stream->avail_in)
1072                 error("garbage at end of loose object '%s'",
1073                       sha1_to_hex(sha1));
1074         free(buf);
1075         return NULL;
1076 }
1077
1078 /*
1079  * We used to just use "sscanf()", but that's actually way
1080  * too permissive for what we want to check. So do an anal
1081  * object header parse by hand.
1082  */
1083 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1084                                unsigned int flags)
1085 {
1086         const char *type_buf = hdr;
1087         unsigned long size;
1088         int type, type_len = 0;
1089
1090         /*
1091          * The type can be of any size but is followed by
1092          * a space.
1093          */
1094         for (;;) {
1095                 char c = *hdr++;
1096                 if (!c)
1097                         return -1;
1098                 if (c == ' ')
1099                         break;
1100                 type_len++;
1101         }
1102
1103         type = type_from_string_gently(type_buf, type_len, 1);
1104         if (oi->typename)
1105                 strbuf_add(oi->typename, type_buf, type_len);
1106         /*
1107          * Set type to 0 if its an unknown object and
1108          * we're obtaining the type using '--allow-unknown-type'
1109          * option.
1110          */
1111         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1112                 type = 0;
1113         else if (type < 0)
1114                 die("invalid object type");
1115         if (oi->typep)
1116                 *oi->typep = type;
1117
1118         /*
1119          * The length must follow immediately, and be in canonical
1120          * decimal format (ie "010" is not valid).
1121          */
1122         size = *hdr++ - '0';
1123         if (size > 9)
1124                 return -1;
1125         if (size) {
1126                 for (;;) {
1127                         unsigned long c = *hdr - '0';
1128                         if (c > 9)
1129                                 break;
1130                         hdr++;
1131                         size = size * 10 + c;
1132                 }
1133         }
1134
1135         if (oi->sizep)
1136                 *oi->sizep = size;
1137
1138         /*
1139          * The length must be followed by a zero byte
1140          */
1141         return *hdr ? -1 : type;
1142 }
1143
1144 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1145 {
1146         struct object_info oi = OBJECT_INFO_INIT;
1147
1148         oi.sizep = sizep;
1149         return parse_sha1_header_extended(hdr, &oi, 0);
1150 }
1151
1152 static int sha1_loose_object_info(const unsigned char *sha1,
1153                                   struct object_info *oi,
1154                                   int flags)
1155 {
1156         int status = 0;
1157         unsigned long mapsize;
1158         void *map;
1159         git_zstream stream;
1160         char hdr[32];
1161         struct strbuf hdrbuf = STRBUF_INIT;
1162         unsigned long size_scratch;
1163
1164         if (oi->delta_base_sha1)
1165                 hashclr(oi->delta_base_sha1);
1166
1167         /*
1168          * If we don't care about type or size, then we don't
1169          * need to look inside the object at all. Note that we
1170          * do not optimize out the stat call, even if the
1171          * caller doesn't care about the disk-size, since our
1172          * return value implicitly indicates whether the
1173          * object even exists.
1174          */
1175         if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1176                 const char *path;
1177                 struct stat st;
1178                 if (stat_sha1_file(the_repository, sha1, &st, &path) < 0)
1179                         return -1;
1180                 if (oi->disk_sizep)
1181                         *oi->disk_sizep = st.st_size;
1182                 return 0;
1183         }
1184
1185         map = map_sha1_file(sha1, &mapsize);
1186         if (!map)
1187                 return -1;
1188
1189         if (!oi->sizep)
1190                 oi->sizep = &size_scratch;
1191
1192         if (oi->disk_sizep)
1193                 *oi->disk_sizep = mapsize;
1194         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1195                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1196                         status = error("unable to unpack %s header with --allow-unknown-type",
1197                                        sha1_to_hex(sha1));
1198         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1199                 status = error("unable to unpack %s header",
1200                                sha1_to_hex(sha1));
1201         if (status < 0)
1202                 ; /* Do nothing */
1203         else if (hdrbuf.len) {
1204                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1205                         status = error("unable to parse %s header with --allow-unknown-type",
1206                                        sha1_to_hex(sha1));
1207         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1208                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1209
1210         if (status >= 0 && oi->contentp) {
1211                 *oi->contentp = unpack_sha1_rest(&stream, hdr,
1212                                                  *oi->sizep, sha1);
1213                 if (!*oi->contentp) {
1214                         git_inflate_end(&stream);
1215                         status = -1;
1216                 }
1217         } else
1218                 git_inflate_end(&stream);
1219
1220         munmap(map, mapsize);
1221         if (status && oi->typep)
1222                 *oi->typep = status;
1223         if (oi->sizep == &size_scratch)
1224                 oi->sizep = NULL;
1225         strbuf_release(&hdrbuf);
1226         oi->whence = OI_LOOSE;
1227         return (status < 0) ? status : 0;
1228 }
1229
1230 int fetch_if_missing = 1;
1231
1232 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1233 {
1234         static struct object_info blank_oi = OBJECT_INFO_INIT;
1235         struct pack_entry e;
1236         int rtype;
1237         const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1238                                     lookup_replace_object(sha1) :
1239                                     sha1;
1240         int already_retried = 0;
1241
1242         if (is_null_sha1(real))
1243                 return -1;
1244
1245         if (!oi)
1246                 oi = &blank_oi;
1247
1248         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1249                 struct cached_object *co = find_cached_object(real);
1250                 if (co) {
1251                         if (oi->typep)
1252                                 *(oi->typep) = co->type;
1253                         if (oi->sizep)
1254                                 *(oi->sizep) = co->size;
1255                         if (oi->disk_sizep)
1256                                 *(oi->disk_sizep) = 0;
1257                         if (oi->delta_base_sha1)
1258                                 hashclr(oi->delta_base_sha1);
1259                         if (oi->typename)
1260                                 strbuf_addstr(oi->typename, typename(co->type));
1261                         if (oi->contentp)
1262                                 *oi->contentp = xmemdupz(co->buf, co->size);
1263                         oi->whence = OI_CACHED;
1264                         return 0;
1265                 }
1266         }
1267
1268         while (1) {
1269                 if (find_pack_entry(real, &e))
1270                         break;
1271
1272                 /* Most likely it's a loose object. */
1273                 if (!sha1_loose_object_info(real, oi, flags))
1274                         return 0;
1275
1276                 /* Not a loose object; someone else may have just packed it. */
1277                 reprepare_packed_git();
1278                 if (find_pack_entry(real, &e))
1279                         break;
1280
1281                 /* Check if it is a missing object */
1282                 if (fetch_if_missing && repository_format_partial_clone &&
1283                     !already_retried) {
1284                         /*
1285                          * TODO Investigate haveing fetch_object() return
1286                          * TODO error/success and stopping the music here.
1287                          */
1288                         fetch_object(repository_format_partial_clone, real);
1289                         already_retried = 1;
1290                         continue;
1291                 }
1292
1293                 return -1;
1294         }
1295
1296         if (oi == &blank_oi)
1297                 /*
1298                  * We know that the caller doesn't actually need the
1299                  * information below, so return early.
1300                  */
1301                 return 0;
1302         rtype = packed_object_info(e.p, e.offset, oi);
1303         if (rtype < 0) {
1304                 mark_bad_packed_object(e.p, real);
1305                 return sha1_object_info_extended(real, oi, 0);
1306         } else if (oi->whence == OI_PACKED) {
1307                 oi->u.packed.offset = e.offset;
1308                 oi->u.packed.pack = e.p;
1309                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1310                                          rtype == OBJ_OFS_DELTA);
1311         }
1312
1313         return 0;
1314 }
1315
1316 /* returns enum object_type or negative */
1317 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1318 {
1319         enum object_type type;
1320         struct object_info oi = OBJECT_INFO_INIT;
1321
1322         oi.typep = &type;
1323         oi.sizep = sizep;
1324         if (sha1_object_info_extended(sha1, &oi,
1325                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1326                 return -1;
1327         return type;
1328 }
1329
1330 static void *read_object(const unsigned char *sha1, enum object_type *type,
1331                          unsigned long *size)
1332 {
1333         struct object_info oi = OBJECT_INFO_INIT;
1334         void *content;
1335         oi.typep = type;
1336         oi.sizep = size;
1337         oi.contentp = &content;
1338
1339         if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1340                 return NULL;
1341         return content;
1342 }
1343
1344 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1345                       unsigned char *sha1)
1346 {
1347         struct cached_object *co;
1348
1349         hash_sha1_file(buf, len, typename(type), sha1);
1350         if (has_sha1_file(sha1) || find_cached_object(sha1))
1351                 return 0;
1352         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1353         co = &cached_objects[cached_object_nr++];
1354         co->size = len;
1355         co->type = type;
1356         co->buf = xmalloc(len);
1357         memcpy(co->buf, buf, len);
1358         hashcpy(co->sha1, sha1);
1359         return 0;
1360 }
1361
1362 /*
1363  * This function dies on corrupt objects; the callers who want to
1364  * deal with them should arrange to call read_object() and give error
1365  * messages themselves.
1366  */
1367 void *read_sha1_file_extended(const unsigned char *sha1,
1368                               enum object_type *type,
1369                               unsigned long *size,
1370                               int lookup_replace)
1371 {
1372         void *data;
1373         const struct packed_git *p;
1374         const char *path;
1375         struct stat st;
1376         const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1377                                                    : sha1;
1378
1379         errno = 0;
1380         data = read_object(repl, type, size);
1381         if (data)
1382                 return data;
1383
1384         if (errno && errno != ENOENT)
1385                 die_errno("failed to read object %s", sha1_to_hex(sha1));
1386
1387         /* die if we replaced an object with one that does not exist */
1388         if (repl != sha1)
1389                 die("replacement %s not found for %s",
1390                     sha1_to_hex(repl), sha1_to_hex(sha1));
1391
1392         if (!stat_sha1_file(the_repository, repl, &st, &path))
1393                 die("loose object %s (stored in %s) is corrupt",
1394                     sha1_to_hex(repl), path);
1395
1396         if ((p = has_packed_and_bad(repl)) != NULL)
1397                 die("packed object %s (stored in %s) is corrupt",
1398                     sha1_to_hex(repl), p->pack_name);
1399
1400         return NULL;
1401 }
1402
1403 void *read_object_with_reference(const unsigned char *sha1,
1404                                  const char *required_type_name,
1405                                  unsigned long *size,
1406                                  unsigned char *actual_sha1_return)
1407 {
1408         enum object_type type, required_type;
1409         void *buffer;
1410         unsigned long isize;
1411         unsigned char actual_sha1[20];
1412
1413         required_type = type_from_string(required_type_name);
1414         hashcpy(actual_sha1, sha1);
1415         while (1) {
1416                 int ref_length = -1;
1417                 const char *ref_type = NULL;
1418
1419                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1420                 if (!buffer)
1421                         return NULL;
1422                 if (type == required_type) {
1423                         *size = isize;
1424                         if (actual_sha1_return)
1425                                 hashcpy(actual_sha1_return, actual_sha1);
1426                         return buffer;
1427                 }
1428                 /* Handle references */
1429                 else if (type == OBJ_COMMIT)
1430                         ref_type = "tree ";
1431                 else if (type == OBJ_TAG)
1432                         ref_type = "object ";
1433                 else {
1434                         free(buffer);
1435                         return NULL;
1436                 }
1437                 ref_length = strlen(ref_type);
1438
1439                 if (ref_length + 40 > isize ||
1440                     memcmp(buffer, ref_type, ref_length) ||
1441                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1442                         free(buffer);
1443                         return NULL;
1444                 }
1445                 free(buffer);
1446                 /* Now we have the ID of the referred-to object in
1447                  * actual_sha1.  Check again. */
1448         }
1449 }
1450
1451 static void write_sha1_file_prepare(const void *buf, unsigned long len,
1452                                     const char *type, unsigned char *sha1,
1453                                     char *hdr, int *hdrlen)
1454 {
1455         git_SHA_CTX c;
1456
1457         /* Generate the header */
1458         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1459
1460         /* Sha1.. */
1461         git_SHA1_Init(&c);
1462         git_SHA1_Update(&c, hdr, *hdrlen);
1463         git_SHA1_Update(&c, buf, len);
1464         git_SHA1_Final(sha1, &c);
1465 }
1466
1467 /*
1468  * Move the just written object into its final resting place.
1469  */
1470 int finalize_object_file(const char *tmpfile, const char *filename)
1471 {
1472         int ret = 0;
1473
1474         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1475                 goto try_rename;
1476         else if (link(tmpfile, filename))
1477                 ret = errno;
1478
1479         /*
1480          * Coda hack - coda doesn't like cross-directory links,
1481          * so we fall back to a rename, which will mean that it
1482          * won't be able to check collisions, but that's not a
1483          * big deal.
1484          *
1485          * The same holds for FAT formatted media.
1486          *
1487          * When this succeeds, we just return.  We have nothing
1488          * left to unlink.
1489          */
1490         if (ret && ret != EEXIST) {
1491         try_rename:
1492                 if (!rename(tmpfile, filename))
1493                         goto out;
1494                 ret = errno;
1495         }
1496         unlink_or_warn(tmpfile);
1497         if (ret) {
1498                 if (ret != EEXIST) {
1499                         return error_errno("unable to write sha1 filename %s", filename);
1500                 }
1501                 /* FIXME!!! Collision check here ? */
1502         }
1503
1504 out:
1505         if (adjust_shared_perm(filename))
1506                 return error("unable to set permission to '%s'", filename);
1507         return 0;
1508 }
1509
1510 static int write_buffer(int fd, const void *buf, size_t len)
1511 {
1512         if (write_in_full(fd, buf, len) < 0)
1513                 return error_errno("file write error");
1514         return 0;
1515 }
1516
1517 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1518                    unsigned char *sha1)
1519 {
1520         char hdr[32];
1521         int hdrlen = sizeof(hdr);
1522         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1523         return 0;
1524 }
1525
1526 /* Finalize a file on disk, and close it. */
1527 static void close_sha1_file(int fd)
1528 {
1529         if (fsync_object_files)
1530                 fsync_or_die(fd, "sha1 file");
1531         if (close(fd) != 0)
1532                 die_errno("error when closing sha1 file");
1533 }
1534
1535 /* Size of directory component, including the ending '/' */
1536 static inline int directory_size(const char *filename)
1537 {
1538         const char *s = strrchr(filename, '/');
1539         if (!s)
1540                 return 0;
1541         return s - filename + 1;
1542 }
1543
1544 /*
1545  * This creates a temporary file in the same directory as the final
1546  * 'filename'
1547  *
1548  * We want to avoid cross-directory filename renames, because those
1549  * can have problems on various filesystems (FAT, NFS, Coda).
1550  */
1551 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1552 {
1553         int fd, dirlen = directory_size(filename);
1554
1555         strbuf_reset(tmp);
1556         strbuf_add(tmp, filename, dirlen);
1557         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1558         fd = git_mkstemp_mode(tmp->buf, 0444);
1559         if (fd < 0 && dirlen && errno == ENOENT) {
1560                 /*
1561                  * Make sure the directory exists; note that the contents
1562                  * of the buffer are undefined after mkstemp returns an
1563                  * error, so we have to rewrite the whole buffer from
1564                  * scratch.
1565                  */
1566                 strbuf_reset(tmp);
1567                 strbuf_add(tmp, filename, dirlen - 1);
1568                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1569                         return -1;
1570                 if (adjust_shared_perm(tmp->buf))
1571                         return -1;
1572
1573                 /* Try again */
1574                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1575                 fd = git_mkstemp_mode(tmp->buf, 0444);
1576         }
1577         return fd;
1578 }
1579
1580 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1581                               const void *buf, unsigned long len, time_t mtime)
1582 {
1583         int fd, ret;
1584         unsigned char compressed[4096];
1585         git_zstream stream;
1586         git_SHA_CTX c;
1587         unsigned char parano_sha1[20];
1588         static struct strbuf tmp_file = STRBUF_INIT;
1589         static struct strbuf filename = STRBUF_INIT;
1590
1591         strbuf_reset(&filename);
1592         sha1_file_name(the_repository, &filename, sha1);
1593
1594         fd = create_tmpfile(&tmp_file, filename.buf);
1595         if (fd < 0) {
1596                 if (errno == EACCES)
1597                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1598                 else
1599                         return error_errno("unable to create temporary file");
1600         }
1601
1602         /* Set it up */
1603         git_deflate_init(&stream, zlib_compression_level);
1604         stream.next_out = compressed;
1605         stream.avail_out = sizeof(compressed);
1606         git_SHA1_Init(&c);
1607
1608         /* First header.. */
1609         stream.next_in = (unsigned char *)hdr;
1610         stream.avail_in = hdrlen;
1611         while (git_deflate(&stream, 0) == Z_OK)
1612                 ; /* nothing */
1613         git_SHA1_Update(&c, hdr, hdrlen);
1614
1615         /* Then the data itself.. */
1616         stream.next_in = (void *)buf;
1617         stream.avail_in = len;
1618         do {
1619                 unsigned char *in0 = stream.next_in;
1620                 ret = git_deflate(&stream, Z_FINISH);
1621                 git_SHA1_Update(&c, in0, stream.next_in - in0);
1622                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1623                         die("unable to write sha1 file");
1624                 stream.next_out = compressed;
1625                 stream.avail_out = sizeof(compressed);
1626         } while (ret == Z_OK);
1627
1628         if (ret != Z_STREAM_END)
1629                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1630         ret = git_deflate_end_gently(&stream);
1631         if (ret != Z_OK)
1632                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1633         git_SHA1_Final(parano_sha1, &c);
1634         if (hashcmp(sha1, parano_sha1) != 0)
1635                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1636
1637         close_sha1_file(fd);
1638
1639         if (mtime) {
1640                 struct utimbuf utb;
1641                 utb.actime = mtime;
1642                 utb.modtime = mtime;
1643                 if (utime(tmp_file.buf, &utb) < 0)
1644                         warning_errno("failed utime() on %s", tmp_file.buf);
1645         }
1646
1647         return finalize_object_file(tmp_file.buf, filename.buf);
1648 }
1649
1650 static int freshen_loose_object(const unsigned char *sha1)
1651 {
1652         return check_and_freshen(sha1, 1);
1653 }
1654
1655 static int freshen_packed_object(const unsigned char *sha1)
1656 {
1657         struct pack_entry e;
1658         if (!find_pack_entry(sha1, &e))
1659                 return 0;
1660         if (e.p->freshened)
1661                 return 1;
1662         if (!freshen_file(e.p->pack_name))
1663                 return 0;
1664         e.p->freshened = 1;
1665         return 1;
1666 }
1667
1668 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1669 {
1670         char hdr[32];
1671         int hdrlen = sizeof(hdr);
1672
1673         /* Normally if we have it in the pack then we do not bother writing
1674          * it out into .git/objects/??/?{38} file.
1675          */
1676         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1677         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1678                 return 0;
1679         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1680 }
1681
1682 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1683                              struct object_id *oid, unsigned flags)
1684 {
1685         char *header;
1686         int hdrlen, status = 0;
1687
1688         /* type string, SP, %lu of the length plus NUL must fit this */
1689         hdrlen = strlen(type) + 32;
1690         header = xmalloc(hdrlen);
1691         write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1692
1693         if (!(flags & HASH_WRITE_OBJECT))
1694                 goto cleanup;
1695         if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1696                 goto cleanup;
1697         status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1698
1699 cleanup:
1700         free(header);
1701         return status;
1702 }
1703
1704 int force_object_loose(const unsigned char *sha1, time_t mtime)
1705 {
1706         void *buf;
1707         unsigned long len;
1708         enum object_type type;
1709         char hdr[32];
1710         int hdrlen;
1711         int ret;
1712
1713         if (has_loose_object(sha1))
1714                 return 0;
1715         buf = read_object(sha1, &type, &len);
1716         if (!buf)
1717                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1718         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1719         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1720         free(buf);
1721
1722         return ret;
1723 }
1724
1725 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1726 {
1727         if (!startup_info->have_repository)
1728                 return 0;
1729         return sha1_object_info_extended(sha1, NULL,
1730                                          flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1731 }
1732
1733 int has_object_file(const struct object_id *oid)
1734 {
1735         return has_sha1_file(oid->hash);
1736 }
1737
1738 int has_object_file_with_flags(const struct object_id *oid, int flags)
1739 {
1740         return has_sha1_file_with_flags(oid->hash, flags);
1741 }
1742
1743 static void check_tree(const void *buf, size_t size)
1744 {
1745         struct tree_desc desc;
1746         struct name_entry entry;
1747
1748         init_tree_desc(&desc, buf, size);
1749         while (tree_entry(&desc, &entry))
1750                 /* do nothing
1751                  * tree_entry() will die() on malformed entries */
1752                 ;
1753 }
1754
1755 static void check_commit(const void *buf, size_t size)
1756 {
1757         struct commit c;
1758         memset(&c, 0, sizeof(c));
1759         if (parse_commit_buffer(&c, buf, size))
1760                 die("corrupt commit");
1761 }
1762
1763 static void check_tag(const void *buf, size_t size)
1764 {
1765         struct tag t;
1766         memset(&t, 0, sizeof(t));
1767         if (parse_tag_buffer(&t, buf, size))
1768                 die("corrupt tag");
1769 }
1770
1771 static int index_mem(struct object_id *oid, void *buf, size_t size,
1772                      enum object_type type,
1773                      const char *path, unsigned flags)
1774 {
1775         int ret, re_allocated = 0;
1776         int write_object = flags & HASH_WRITE_OBJECT;
1777
1778         if (!type)
1779                 type = OBJ_BLOB;
1780
1781         /*
1782          * Convert blobs to git internal format
1783          */
1784         if ((type == OBJ_BLOB) && path) {
1785                 struct strbuf nbuf = STRBUF_INIT;
1786                 if (convert_to_git(&the_index, path, buf, size, &nbuf,
1787                                    get_conv_flags(flags))) {
1788                         buf = strbuf_detach(&nbuf, &size);
1789                         re_allocated = 1;
1790                 }
1791         }
1792         if (flags & HASH_FORMAT_CHECK) {
1793                 if (type == OBJ_TREE)
1794                         check_tree(buf, size);
1795                 if (type == OBJ_COMMIT)
1796                         check_commit(buf, size);
1797                 if (type == OBJ_TAG)
1798                         check_tag(buf, size);
1799         }
1800
1801         if (write_object)
1802                 ret = write_sha1_file(buf, size, typename(type), oid->hash);
1803         else
1804                 ret = hash_sha1_file(buf, size, typename(type), oid->hash);
1805         if (re_allocated)
1806                 free(buf);
1807         return ret;
1808 }
1809
1810 static int index_stream_convert_blob(struct object_id *oid, int fd,
1811                                      const char *path, unsigned flags)
1812 {
1813         int ret;
1814         const int write_object = flags & HASH_WRITE_OBJECT;
1815         struct strbuf sbuf = STRBUF_INIT;
1816
1817         assert(path);
1818         assert(would_convert_to_git_filter_fd(path));
1819
1820         convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1821                                  get_conv_flags(flags));
1822
1823         if (write_object)
1824                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1825                                       oid->hash);
1826         else
1827                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1828                                      oid->hash);
1829         strbuf_release(&sbuf);
1830         return ret;
1831 }
1832
1833 static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1834                       const char *path, unsigned flags)
1835 {
1836         struct strbuf sbuf = STRBUF_INIT;
1837         int ret;
1838
1839         if (strbuf_read(&sbuf, fd, 4096) >= 0)
1840                 ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1841         else
1842                 ret = -1;
1843         strbuf_release(&sbuf);
1844         return ret;
1845 }
1846
1847 #define SMALL_FILE_SIZE (32*1024)
1848
1849 static int index_core(struct object_id *oid, int fd, size_t size,
1850                       enum object_type type, const char *path,
1851                       unsigned flags)
1852 {
1853         int ret;
1854
1855         if (!size) {
1856                 ret = index_mem(oid, "", size, type, path, flags);
1857         } else if (size <= SMALL_FILE_SIZE) {
1858                 char *buf = xmalloc(size);
1859                 ssize_t read_result = read_in_full(fd, buf, size);
1860                 if (read_result < 0)
1861                         ret = error_errno("read error while indexing %s",
1862                                           path ? path : "<unknown>");
1863                 else if (read_result != size)
1864                         ret = error("short read while indexing %s",
1865                                     path ? path : "<unknown>");
1866                 else
1867                         ret = index_mem(oid, buf, size, type, path, flags);
1868                 free(buf);
1869         } else {
1870                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1871                 ret = index_mem(oid, buf, size, type, path, flags);
1872                 munmap(buf, size);
1873         }
1874         return ret;
1875 }
1876
1877 /*
1878  * This creates one packfile per large blob unless bulk-checkin
1879  * machinery is "plugged".
1880  *
1881  * This also bypasses the usual "convert-to-git" dance, and that is on
1882  * purpose. We could write a streaming version of the converting
1883  * functions and insert that before feeding the data to fast-import
1884  * (or equivalent in-core API described above). However, that is
1885  * somewhat complicated, as we do not know the size of the filter
1886  * result, which we need to know beforehand when writing a git object.
1887  * Since the primary motivation for trying to stream from the working
1888  * tree file and to avoid mmaping it in core is to deal with large
1889  * binary blobs, they generally do not want to get any conversion, and
1890  * callers should avoid this code path when filters are requested.
1891  */
1892 static int index_stream(struct object_id *oid, int fd, size_t size,
1893                         enum object_type type, const char *path,
1894                         unsigned flags)
1895 {
1896         return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1897 }
1898
1899 int index_fd(struct object_id *oid, int fd, struct stat *st,
1900              enum object_type type, const char *path, unsigned flags)
1901 {
1902         int ret;
1903
1904         /*
1905          * Call xsize_t() only when needed to avoid potentially unnecessary
1906          * die() for large files.
1907          */
1908         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1909                 ret = index_stream_convert_blob(oid, fd, path, flags);
1910         else if (!S_ISREG(st->st_mode))
1911                 ret = index_pipe(oid, fd, type, path, flags);
1912         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1913                  (path && would_convert_to_git(&the_index, path)))
1914                 ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1915                                  flags);
1916         else
1917                 ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1918                                    flags);
1919         close(fd);
1920         return ret;
1921 }
1922
1923 int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1924 {
1925         int fd;
1926         struct strbuf sb = STRBUF_INIT;
1927         int rc = 0;
1928
1929         switch (st->st_mode & S_IFMT) {
1930         case S_IFREG:
1931                 fd = open(path, O_RDONLY);
1932                 if (fd < 0)
1933                         return error_errno("open(\"%s\")", path);
1934                 if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1935                         return error("%s: failed to insert into database",
1936                                      path);
1937                 break;
1938         case S_IFLNK:
1939                 if (strbuf_readlink(&sb, path, st->st_size))
1940                         return error_errno("readlink(\"%s\")", path);
1941                 if (!(flags & HASH_WRITE_OBJECT))
1942                         hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1943                 else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1944                         rc = error("%s: failed to insert into database", path);
1945                 strbuf_release(&sb);
1946                 break;
1947         case S_IFDIR:
1948                 return resolve_gitlink_ref(path, "HEAD", oid);
1949         default:
1950                 return error("%s: unsupported file type", path);
1951         }
1952         return rc;
1953 }
1954
1955 int read_pack_header(int fd, struct pack_header *header)
1956 {
1957         if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1958                 /* "eof before pack header was fully read" */
1959                 return PH_ERROR_EOF;
1960
1961         if (header->hdr_signature != htonl(PACK_SIGNATURE))
1962                 /* "protocol error (pack signature mismatch detected)" */
1963                 return PH_ERROR_PACK_SIGNATURE;
1964         if (!pack_version_ok(header->hdr_version))
1965                 /* "protocol error (pack version unsupported)" */
1966                 return PH_ERROR_PROTOCOL;
1967         return 0;
1968 }
1969
1970 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1971 {
1972         enum object_type type = sha1_object_info(sha1, NULL);
1973         if (type < 0)
1974                 die("%s is not a valid object", sha1_to_hex(sha1));
1975         if (type != expect)
1976                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1977                     typename(expect));
1978 }
1979
1980 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1981                                 struct strbuf *path,
1982                                 each_loose_object_fn obj_cb,
1983                                 each_loose_cruft_fn cruft_cb,
1984                                 each_loose_subdir_fn subdir_cb,
1985                                 void *data)
1986 {
1987         size_t origlen, baselen;
1988         DIR *dir;
1989         struct dirent *de;
1990         int r = 0;
1991         struct object_id oid;
1992
1993         if (subdir_nr > 0xff)
1994                 BUG("invalid loose object subdirectory: %x", subdir_nr);
1995
1996         origlen = path->len;
1997         strbuf_complete(path, '/');
1998         strbuf_addf(path, "%02x", subdir_nr);
1999
2000         dir = opendir(path->buf);
2001         if (!dir) {
2002                 if (errno != ENOENT)
2003                         r = error_errno("unable to open %s", path->buf);
2004                 strbuf_setlen(path, origlen);
2005                 return r;
2006         }
2007
2008         oid.hash[0] = subdir_nr;
2009         strbuf_addch(path, '/');
2010         baselen = path->len;
2011
2012         while ((de = readdir(dir))) {
2013                 size_t namelen;
2014                 if (is_dot_or_dotdot(de->d_name))
2015                         continue;
2016
2017                 namelen = strlen(de->d_name);
2018                 strbuf_setlen(path, baselen);
2019                 strbuf_add(path, de->d_name, namelen);
2020                 if (namelen == GIT_SHA1_HEXSZ - 2 &&
2021                     !hex_to_bytes(oid.hash + 1, de->d_name,
2022                                   GIT_SHA1_RAWSZ - 1)) {
2023                         if (obj_cb) {
2024                                 r = obj_cb(&oid, path->buf, data);
2025                                 if (r)
2026                                         break;
2027                         }
2028                         continue;
2029                 }
2030
2031                 if (cruft_cb) {
2032                         r = cruft_cb(de->d_name, path->buf, data);
2033                         if (r)
2034                                 break;
2035                 }
2036         }
2037         closedir(dir);
2038
2039         strbuf_setlen(path, baselen - 1);
2040         if (!r && subdir_cb)
2041                 r = subdir_cb(subdir_nr, path->buf, data);
2042
2043         strbuf_setlen(path, origlen);
2044
2045         return r;
2046 }
2047
2048 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2049                             each_loose_object_fn obj_cb,
2050                             each_loose_cruft_fn cruft_cb,
2051                             each_loose_subdir_fn subdir_cb,
2052                             void *data)
2053 {
2054         int r = 0;
2055         int i;
2056
2057         for (i = 0; i < 256; i++) {
2058                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2059                                                 subdir_cb, data);
2060                 if (r)
2061                         break;
2062         }
2063
2064         return r;
2065 }
2066
2067 int for_each_loose_file_in_objdir(const char *path,
2068                                   each_loose_object_fn obj_cb,
2069                                   each_loose_cruft_fn cruft_cb,
2070                                   each_loose_subdir_fn subdir_cb,
2071                                   void *data)
2072 {
2073         struct strbuf buf = STRBUF_INIT;
2074         int r;
2075
2076         strbuf_addstr(&buf, path);
2077         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2078                                               subdir_cb, data);
2079         strbuf_release(&buf);
2080
2081         return r;
2082 }
2083
2084 struct loose_alt_odb_data {
2085         each_loose_object_fn *cb;
2086         void *data;
2087 };
2088
2089 static int loose_from_alt_odb(struct alternate_object_database *alt,
2090                               void *vdata)
2091 {
2092         struct loose_alt_odb_data *data = vdata;
2093         struct strbuf buf = STRBUF_INIT;
2094         int r;
2095
2096         strbuf_addstr(&buf, alt->path);
2097         r = for_each_loose_file_in_objdir_buf(&buf,
2098                                               data->cb, NULL, NULL,
2099                                               data->data);
2100         strbuf_release(&buf);
2101         return r;
2102 }
2103
2104 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2105 {
2106         struct loose_alt_odb_data alt;
2107         int r;
2108
2109         r = for_each_loose_file_in_objdir(get_object_directory(),
2110                                           cb, NULL, NULL, data);
2111         if (r)
2112                 return r;
2113
2114         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2115                 return 0;
2116
2117         alt.cb = cb;
2118         alt.data = data;
2119         return foreach_alt_odb(loose_from_alt_odb, &alt);
2120 }
2121
2122 static int check_stream_sha1(git_zstream *stream,
2123                              const char *hdr,
2124                              unsigned long size,
2125                              const char *path,
2126                              const unsigned char *expected_sha1)
2127 {
2128         git_SHA_CTX c;
2129         unsigned char real_sha1[GIT_MAX_RAWSZ];
2130         unsigned char buf[4096];
2131         unsigned long total_read;
2132         int status = Z_OK;
2133
2134         git_SHA1_Init(&c);
2135         git_SHA1_Update(&c, hdr, stream->total_out);
2136
2137         /*
2138          * We already read some bytes into hdr, but the ones up to the NUL
2139          * do not count against the object's content size.
2140          */
2141         total_read = stream->total_out - strlen(hdr) - 1;
2142
2143         /*
2144          * This size comparison must be "<=" to read the final zlib packets;
2145          * see the comment in unpack_sha1_rest for details.
2146          */
2147         while (total_read <= size &&
2148                (status == Z_OK || status == Z_BUF_ERROR)) {
2149                 stream->next_out = buf;
2150                 stream->avail_out = sizeof(buf);
2151                 if (size - total_read < stream->avail_out)
2152                         stream->avail_out = size - total_read;
2153                 status = git_inflate(stream, Z_FINISH);
2154                 git_SHA1_Update(&c, buf, stream->next_out - buf);
2155                 total_read += stream->next_out - buf;
2156         }
2157         git_inflate_end(stream);
2158
2159         if (status != Z_STREAM_END) {
2160                 error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2161                 return -1;
2162         }
2163         if (stream->avail_in) {
2164                 error("garbage at end of loose object '%s'",
2165                       sha1_to_hex(expected_sha1));
2166                 return -1;
2167         }
2168
2169         git_SHA1_Final(real_sha1, &c);
2170         if (hashcmp(expected_sha1, real_sha1)) {
2171                 error("sha1 mismatch for %s (expected %s)", path,
2172                       sha1_to_hex(expected_sha1));
2173                 return -1;
2174         }
2175
2176         return 0;
2177 }
2178
2179 int read_loose_object(const char *path,
2180                       const unsigned char *expected_sha1,
2181                       enum object_type *type,
2182                       unsigned long *size,
2183                       void **contents)
2184 {
2185         int ret = -1;
2186         void *map = NULL;
2187         unsigned long mapsize;
2188         git_zstream stream;
2189         char hdr[32];
2190
2191         *contents = NULL;
2192
2193         map = map_sha1_file_1(path, NULL, &mapsize);
2194         if (!map) {
2195                 error_errno("unable to mmap %s", path);
2196                 goto out;
2197         }
2198
2199         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2200                 error("unable to unpack header of %s", path);
2201                 goto out;
2202         }
2203
2204         *type = parse_sha1_header(hdr, size);
2205         if (*type < 0) {
2206                 error("unable to parse header of %s", path);
2207                 git_inflate_end(&stream);
2208                 goto out;
2209         }
2210
2211         if (*type == OBJ_BLOB) {
2212                 if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2213                         goto out;
2214         } else {
2215                 *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2216                 if (!*contents) {
2217                         error("unable to unpack contents of %s", path);
2218                         git_inflate_end(&stream);
2219                         goto out;
2220                 }
2221                 if (check_sha1_signature(expected_sha1, *contents,
2222                                          *size, typename(*type))) {
2223                         error("sha1 mismatch for %s (expected %s)", path,
2224                               sha1_to_hex(expected_sha1));
2225                         free(*contents);
2226                         goto out;
2227                 }
2228         }
2229
2230         ret = 0; /* everything checks out */
2231
2232 out:
2233         if (map)
2234                 munmap(map, mapsize);
2235         return ret;
2236 }