git.oblomov.eu Git - git/blob - sha1_file.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  *
   6  * This handles basic git sha1 object files - packing, unpacking,
   7  * creation etc.
   8  */
   9 #include "cache.h"
  10 #include "config.h"
  11 #include "string-list.h"
  12 #include "lockfile.h"
  13 #include "delta.h"
  14 #include "pack.h"
  15 #include "blob.h"
  16 #include "commit.h"
  17 #include "run-command.h"
  18 #include "tag.h"
  19 #include "tree.h"
  20 #include "tree-walk.h"
  21 #include "refs.h"
  22 #include "pack-revindex.h"
  23 #include "sha1-lookup.h"
  24 #include "bulk-checkin.h"
  25 #include "streaming.h"
  26 #include "dir.h"
  27 #include "list.h"
  28 #include "mergesort.h"
  29 #include "quote.h"
  30 #include "packfile.h"
  31 #include "fetch-object.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 static void git_hash_sha1_init(void *ctx)
  43 {
  44         git_SHA1_Init((git_SHA_CTX *)ctx);
  45 }
  46
  47 static void git_hash_sha1_update(void *ctx, const void *data, size_t len)
  48 {
  49         git_SHA1_Update((git_SHA_CTX *)ctx, data, len);
  50 }
  51
  52 static void git_hash_sha1_final(unsigned char *hash, void *ctx)
  53 {
  54         git_SHA1_Final(hash, (git_SHA_CTX *)ctx);
  55 }
  56
  57 static void git_hash_unknown_init(void *ctx)
  58 {
  59         die("trying to init unknown hash");
  60 }
  61
  62 static void git_hash_unknown_update(void *ctx, const void *data, size_t len)
  63 {
  64         die("trying to update unknown hash");
  65 }
  66
  67 static void git_hash_unknown_final(unsigned char *hash, void *ctx)
  68 {
  69         die("trying to finalize unknown hash");
  70 }
  71
  72 const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
  73         {
  74                 NULL,
  75                 0x00000000,
  76                 0,
  77                 0,
  78                 0,
  79                 git_hash_unknown_init,
  80                 git_hash_unknown_update,
  81                 git_hash_unknown_final,
  82                 NULL,
  83                 NULL,
  84         },
  85         {
  86                 "sha-1",
  87                 /* "sha1", big-endian */
  88                 0x73686131,
  89                 sizeof(git_SHA_CTX),
  90                 GIT_SHA1_RAWSZ,
  91                 GIT_SHA1_HEXSZ,
  92                 git_hash_sha1_init,
  93                 git_hash_sha1_update,
  94                 git_hash_sha1_final,
  95                 &empty_tree_oid,
  96                 &empty_blob_oid,
  97         },
  98 };
  99
 100 /*
 101  * This is meant to hold a *small* number of objects that you would
 102  * want read_sha1_file() to be able to return, but yet you do not want
 103  * to write them into the object store (e.g. a browse-only
 104  * application).
 105  */
 106 static struct cached_object {
 107         unsigned char sha1[20];
 108         enum object_type type;
 109         void *buf;
 110         unsigned long size;
 111 } *cached_objects;
 112 static int cached_object_nr, cached_object_alloc;
 113
 114 static struct cached_object empty_tree = {
 115         EMPTY_TREE_SHA1_BIN_LITERAL,
 116         OBJ_TREE,
 117         "",
 118         0
 119 };
 120
 121 static struct cached_object *find_cached_object(const unsigned char *sha1)
 122 {
 123         int i;
 124         struct cached_object *co = cached_objects;
 125
 126         for (i = 0; i < cached_object_nr; i++, co++) {
 127                 if (!hashcmp(co->sha1, sha1))
 128                         return co;
 129         }
 130         if (!hashcmp(sha1, empty_tree.sha1))
 131                 return &empty_tree;
 132         return NULL;
 133 }
 134
 135
 136 static int get_conv_flags(unsigned flags)
 137 {
 138         if (flags & HASH_RENORMALIZE)
 139                 return CONV_EOL_RENORMALIZE;
 140         else if (flags & HASH_WRITE_OBJECT)
 141           return global_conv_flags_eol;
 142         else
 143                 return 0;
 144 }
 145
 146
 147 int mkdir_in_gitdir(const char *path)
 148 {
 149         if (mkdir(path, 0777)) {
 150                 int saved_errno = errno;
 151                 struct stat st;
 152                 struct strbuf sb = STRBUF_INIT;
 153
 154                 if (errno != EEXIST)
 155                         return -1;
 156                 /*
 157                  * Are we looking at a path in a symlinked worktree
 158                  * whose original repository does not yet have it?
 159                  * e.g. .git/rr-cache pointing at its original
 160                  * repository in which the user hasn't performed any
 161                  * conflict resolution yet?
 162                  */
 163                 if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 164                     strbuf_readlink(&sb, path, st.st_size) ||
 165                     !is_absolute_path(sb.buf) ||
 166                     mkdir(sb.buf, 0777)) {
 167                         strbuf_release(&sb);
 168                         errno = saved_errno;
 169                         return -1;
 170                 }
 171                 strbuf_release(&sb);
 172         }
 173         return adjust_shared_perm(path);
 174 }
 175
 176 enum scld_error safe_create_leading_directories(char *path)
 177 {
 178         char *next_component = path + offset_1st_component(path);
 179         enum scld_error ret = SCLD_OK;
 180
 181         while (ret == SCLD_OK && next_component) {
 182                 struct stat st;
 183                 char *slash = next_component, slash_character;
 184
 185                 while (*slash && !is_dir_sep(*slash))
 186                         slash++;
 187
 188                 if (!*slash)
 189                         break;
 190
 191                 next_component = slash + 1;
 192                 while (is_dir_sep(*next_component))
 193                         next_component++;
 194                 if (!*next_component)
 195                         break;
 196
 197                 slash_character = *slash;
 198                 *slash = '\0';
 199                 if (!stat(path, &st)) {
 200                         /* path exists */
 201                         if (!S_ISDIR(st.st_mode)) {
 202                                 errno = ENOTDIR;
 203                                 ret = SCLD_EXISTS;
 204                         }
 205                 } else if (mkdir(path, 0777)) {
 206                         if (errno == EEXIST &&
 207                             !stat(path, &st) && S_ISDIR(st.st_mode))
 208                                 ; /* somebody created it since we checked */
 209                         else if (errno == ENOENT)
 210                                 /*
 211                                  * Either mkdir() failed because
 212                                  * somebody just pruned the containing
 213                                  * directory, or stat() failed because
 214                                  * the file that was in our way was
 215                                  * just removed.  Either way, inform
 216                                  * the caller that it might be worth
 217                                  * trying again:
 218                                  */
 219                                 ret = SCLD_VANISHED;
 220                         else
 221                                 ret = SCLD_FAILED;
 222                 } else if (adjust_shared_perm(path)) {
 223                         ret = SCLD_PERMS;
 224                 }
 225                 *slash = slash_character;
 226         }
 227         return ret;
 228 }
 229
 230 enum scld_error safe_create_leading_directories_const(const char *path)
 231 {
 232         int save_errno;
 233         /* path points to cache entries, so xstrdup before messing with it */
 234         char *buf = xstrdup(path);
 235         enum scld_error result = safe_create_leading_directories(buf);
 236
 237         save_errno = errno;
 238         free(buf);
 239         errno = save_errno;
 240         return result;
 241 }
 242
 243 int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 244 {
 245         /*
 246          * The number of times we will try to remove empty directories
 247          * in the way of path. This is only 1 because if another
 248          * process is racily creating directories that conflict with
 249          * us, we don't want to fight against them.
 250          */
 251         int remove_directories_remaining = 1;
 252
 253         /*
 254          * The number of times that we will try to create the
 255          * directories containing path. We are willing to attempt this
 256          * more than once, because another process could be trying to
 257          * clean up empty directories at the same time as we are
 258          * trying to create them.
 259          */
 260         int create_directories_remaining = 3;
 261
 262         /* A scratch copy of path, filled lazily if we need it: */
 263         struct strbuf path_copy = STRBUF_INIT;
 264
 265         int ret, save_errno;
 266
 267         /* Sanity check: */
 268         assert(*path);
 269
 270 retry_fn:
 271         ret = fn(path, cb);
 272         save_errno = errno;
 273         if (!ret)
 274                 goto out;
 275
 276         if (errno == EISDIR && remove_directories_remaining-- > 0) {
 277                 /*
 278                  * A directory is in the way. Maybe it is empty; try
 279                  * to remove it:
 280                  */
 281                 if (!path_copy.len)
 282                         strbuf_addstr(&path_copy, path);
 283
 284                 if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 285                         goto retry_fn;
 286         } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 287                 /*
 288                  * Maybe the containing directory didn't exist, or
 289                  * maybe it was just deleted by a process that is
 290                  * racing with us to clean up empty directories. Try
 291                  * to create it:
 292                  */
 293                 enum scld_error scld_result;
 294
 295                 if (!path_copy.len)
 296                         strbuf_addstr(&path_copy, path);
 297
 298                 do {
 299                         scld_result = safe_create_leading_directories(path_copy.buf);
 300                         if (scld_result == SCLD_OK)
 301                                 goto retry_fn;
 302                 } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 303         }
 304
 305 out:
 306         strbuf_release(&path_copy);
 307         errno = save_errno;
 308         return ret;
 309 }
 310
 311 static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 312 {
 313         int i;
 314         for (i = 0; i < 20; i++) {
 315                 static char hex[] = "0123456789abcdef";
 316                 unsigned int val = sha1[i];
 317                 strbuf_addch(buf, hex[val >> 4]);
 318                 strbuf_addch(buf, hex[val & 0xf]);
 319                 if (!i)
 320                         strbuf_addch(buf, '/');
 321         }
 322 }
 323
 324 const char *sha1_file_name(const unsigned char *sha1)
 325 {
 326         static struct strbuf buf = STRBUF_INIT;
 327
 328         strbuf_reset(&buf);
 329         strbuf_addf(&buf, "%s/", get_object_directory());
 330
 331         fill_sha1_path(&buf, sha1);
 332         return buf.buf;
 333 }
 334
 335 struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 336 {
 337         strbuf_setlen(&alt->scratch, alt->base_len);
 338         return &alt->scratch;
 339 }
 340
 341 static const char *alt_sha1_path(struct alternate_object_database *alt,
 342                                  const unsigned char *sha1)
 343 {
 344         struct strbuf *buf = alt_scratch_buf(alt);
 345         fill_sha1_path(buf, sha1);
 346         return buf->buf;
 347 }
 348
 349 struct alternate_object_database *alt_odb_list;
 350 static struct alternate_object_database **alt_odb_tail;
 351
 352 /*
 353  * Return non-zero iff the path is usable as an alternate object database.
 354  */
 355 static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 356 {
 357         struct alternate_object_database *alt;
 358
 359         /* Detect cases where alternate disappeared */
 360         if (!is_directory(path->buf)) {
 361                 error("object directory %s does not exist; "
 362                       "check .git/objects/info/alternates.",
 363                       path->buf);
 364                 return 0;
 365         }
 366
 367         /*
 368          * Prevent the common mistake of listing the same
 369          * thing twice, or object directory itself.
 370          */
 371         for (alt = alt_odb_list; alt; alt = alt->next) {
 372                 if (!fspathcmp(path->buf, alt->path))
 373                         return 0;
 374         }
 375         if (!fspathcmp(path->buf, normalized_objdir))
 376                 return 0;
 377
 378         return 1;
 379 }
 380
 381 /*
 382  * Prepare alternate object database registry.
 383  *
 384  * The variable alt_odb_list points at the list of struct
 385  * alternate_object_database.  The elements on this list come from
 386  * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 387  * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 388  * whose contents is similar to that environment variable but can be
 389  * LF separated.  Its base points at a statically allocated buffer that
 390  * contains "/the/directory/corresponding/to/.git/objects/...", while
 391  * its name points just after the slash at the end of ".git/objects/"
 392  * in the example above, and has enough space to hold 40-byte hex
 393  * SHA1, an extra slash for the first level indirection, and the
 394  * terminating NUL.
 395  */
 396 static void read_info_alternates(const char * relative_base, int depth);
 397 static int link_alt_odb_entry(const char *entry, const char *relative_base,
 398         int depth, const char *normalized_objdir)
 399 {
 400         struct alternate_object_database *ent;
 401         struct strbuf pathbuf = STRBUF_INIT;
 402
 403         if (!is_absolute_path(entry) && relative_base) {
 404                 strbuf_realpath(&pathbuf, relative_base, 1);
 405                 strbuf_addch(&pathbuf, '/');
 406         }
 407         strbuf_addstr(&pathbuf, entry);
 408
 409         if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 410                 error("unable to normalize alternate object path: %s",
 411                       pathbuf.buf);
 412                 strbuf_release(&pathbuf);
 413                 return -1;
 414         }
 415
 416         /*
 417          * The trailing slash after the directory name is given by
 418          * this function at the end. Remove duplicates.
 419          */
 420         while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 421                 strbuf_setlen(&pathbuf, pathbuf.len - 1);
 422
 423         if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 424                 strbuf_release(&pathbuf);
 425                 return -1;
 426         }
 427
 428         ent = alloc_alt_odb(pathbuf.buf);
 429
 430         /* add the alternate entry */
 431         *alt_odb_tail = ent;
 432         alt_odb_tail = &(ent->next);
 433         ent->next = NULL;
 434
 435         /* recursively add alternates */
 436         read_info_alternates(pathbuf.buf, depth + 1);
 437
 438         strbuf_release(&pathbuf);
 439         return 0;
 440 }
 441
 442 static const char *parse_alt_odb_entry(const char *string,
 443                                        int sep,
 444                                        struct strbuf *out)
 445 {
 446         const char *end;
 447
 448         strbuf_reset(out);
 449
 450         if (*string == '#') {
 451                 /* comment; consume up to next separator */
 452                 end = strchrnul(string, sep);
 453         } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 454                 /*
 455                  * quoted path; unquote_c_style has copied the
 456                  * data for us and set "end". Broken quoting (e.g.,
 457                  * an entry that doesn't end with a quote) falls
 458                  * back to the unquoted case below.
 459                  */
 460         } else {
 461                 /* normal, unquoted path */
 462                 end = strchrnul(string, sep);
 463                 strbuf_add(out, string, end - string);
 464         }
 465
 466         if (*end)
 467                 end++;
 468         return end;
 469 }
 470
 471 static void link_alt_odb_entries(const char *alt, int sep,
 472                                  const char *relative_base, int depth)
 473 {
 474         struct strbuf objdirbuf = STRBUF_INIT;
 475         struct strbuf entry = STRBUF_INIT;
 476
 477         if (!alt || !*alt)
 478                 return;
 479
 480         if (depth > 5) {
 481                 error("%s: ignoring alternate object stores, nesting too deep.",
 482                                 relative_base);
 483                 return;
 484         }
 485
 486         strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 487         if (strbuf_normalize_path(&objdirbuf) < 0)
 488                 die("unable to normalize object directory: %s",
 489                     objdirbuf.buf);
 490
 491         while (*alt) {
 492                 alt = parse_alt_odb_entry(alt, sep, &entry);
 493                 if (!entry.len)
 494                         continue;
 495                 link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 496         }
 497         strbuf_release(&entry);
 498         strbuf_release(&objdirbuf);
 499 }
 500
 501 static void read_info_alternates(const char * relative_base, int depth)
 502 {
 503         char *path;
 504         struct strbuf buf = STRBUF_INIT;
 505
 506         path = xstrfmt("%s/info/alternates", relative_base);
 507         if (strbuf_read_file(&buf, path, 1024) < 0) {
 508                 warn_on_fopen_errors(path);
 509                 free(path);
 510                 return;
 511         }
 512
 513         link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 514         strbuf_release(&buf);
 515         free(path);
 516 }
 517
 518 struct alternate_object_database *alloc_alt_odb(const char *dir)
 519 {
 520         struct alternate_object_database *ent;
 521
 522         FLEX_ALLOC_STR(ent, path, dir);
 523         strbuf_init(&ent->scratch, 0);
 524         strbuf_addf(&ent->scratch, "%s/", dir);
 525         ent->base_len = ent->scratch.len;
 526
 527         return ent;
 528 }
 529
 530 void add_to_alternates_file(const char *reference)
 531 {
 532         struct lock_file lock = LOCK_INIT;
 533         char *alts = git_pathdup("objects/info/alternates");
 534         FILE *in, *out;
 535         int found = 0;
 536
 537         hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 538         out = fdopen_lock_file(&lock, "w");
 539         if (!out)
 540                 die_errno("unable to fdopen alternates lockfile");
 541
 542         in = fopen(alts, "r");
 543         if (in) {
 544                 struct strbuf line = STRBUF_INIT;
 545
 546                 while (strbuf_getline(&line, in) != EOF) {
 547                         if (!strcmp(reference, line.buf)) {
 548                                 found = 1;
 549                                 break;
 550                         }
 551                         fprintf_or_die(out, "%s\n", line.buf);
 552                 }
 553
 554                 strbuf_release(&line);
 555                 fclose(in);
 556         }
 557         else if (errno != ENOENT)
 558                 die_errno("unable to read alternates file");
 559
 560         if (found) {
 561                 rollback_lock_file(&lock);
 562         } else {
 563                 fprintf_or_die(out, "%s\n", reference);
 564                 if (commit_lock_file(&lock))
 565                         die_errno("unable to move new alternates file into place");
 566                 if (alt_odb_tail)
 567                         link_alt_odb_entries(reference, '\n', NULL, 0);
 568         }
 569         free(alts);
 570 }
 571
 572 void add_to_alternates_memory(const char *reference)
 573 {
 574         /*
 575          * Make sure alternates are initialized, or else our entry may be
 576          * overwritten when they are.
 577          */
 578         prepare_alt_odb();
 579
 580         link_alt_odb_entries(reference, '\n', NULL, 0);
 581 }
 582
 583 /*
 584  * Compute the exact path an alternate is at and returns it. In case of
 585  * error NULL is returned and the human readable error is added to `err`
 586  * `path` may be relative and should point to $GITDIR.
 587  * `err` must not be null.
 588  */
 589 char *compute_alternate_path(const char *path, struct strbuf *err)
 590 {
 591         char *ref_git = NULL;
 592         const char *repo, *ref_git_s;
 593         int seen_error = 0;
 594
 595         ref_git_s = real_path_if_valid(path);
 596         if (!ref_git_s) {
 597                 seen_error = 1;
 598                 strbuf_addf(err, _("path '%s' does not exist"), path);
 599                 goto out;
 600         } else
 601                 /*
 602                  * Beware: read_gitfile(), real_path() and mkpath()
 603                  * return static buffer
 604                  */
 605                 ref_git = xstrdup(ref_git_s);
 606
 607         repo = read_gitfile(ref_git);
 608         if (!repo)
 609                 repo = read_gitfile(mkpath("%s/.git", ref_git));
 610         if (repo) {
 611                 free(ref_git);
 612                 ref_git = xstrdup(repo);
 613         }
 614
 615         if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 616                 char *ref_git_git = mkpathdup("%s/.git", ref_git);
 617                 free(ref_git);
 618                 ref_git = ref_git_git;
 619         } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 620                 struct strbuf sb = STRBUF_INIT;
 621                 seen_error = 1;
 622                 if (get_common_dir(&sb, ref_git)) {
 623                         strbuf_addf(err,
 624                                     _("reference repository '%s' as a linked "
 625                                       "checkout is not supported yet."),
 626                                     path);
 627                         goto out;
 628                 }
 629
 630                 strbuf_addf(err, _("reference repository '%s' is not a "
 631                                         "local repository."), path);
 632                 goto out;
 633         }
 634
 635         if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 636                 strbuf_addf(err, _("reference repository '%s' is shallow"),
 637                             path);
 638                 seen_error = 1;
 639                 goto out;
 640         }
 641
 642         if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 643                 strbuf_addf(err,
 644                             _("reference repository '%s' is grafted"),
 645                             path);
 646                 seen_error = 1;
 647                 goto out;
 648         }
 649
 650 out:
 651         if (seen_error) {
 652                 FREE_AND_NULL(ref_git);
 653         }
 654
 655         return ref_git;
 656 }
 657
 658 int foreach_alt_odb(alt_odb_fn fn, void *cb)
 659 {
 660         struct alternate_object_database *ent;
 661         int r = 0;
 662
 663         prepare_alt_odb();
 664         for (ent = alt_odb_list; ent; ent = ent->next) {
 665                 r = fn(ent, cb);
 666                 if (r)
 667                         break;
 668         }
 669         return r;
 670 }
 671
 672 void prepare_alt_odb(void)
 673 {
 674         const char *alt;
 675
 676         if (alt_odb_tail)
 677                 return;
 678
 679         alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 680
 681         alt_odb_tail = &alt_odb_list;
 682         link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
 683
 684         read_info_alternates(get_object_directory(), 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         return check_and_freshen_file(sha1_file_name(sha1), freshen);
 714 }
 715
 716 static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 717 {
 718         struct alternate_object_database *alt;
 719         prepare_alt_odb();
 720         for (alt = alt_odb_list; alt; alt = alt->next) {
 721                 const char *path = alt_sha1_path(alt, sha1);
 722                 if (check_and_freshen_file(path, freshen))
 723                         return 1;
 724         }
 725         return 0;
 726 }
 727
 728 static int check_and_freshen(const unsigned char *sha1, int freshen)
 729 {
 730         return check_and_freshen_local(sha1, freshen) ||
 731                check_and_freshen_nonlocal(sha1, freshen);
 732 }
 733
 734 int has_loose_object_nonlocal(const unsigned char *sha1)
 735 {
 736         return check_and_freshen_nonlocal(sha1, 0);
 737 }
 738
 739 static int has_loose_object(const unsigned char *sha1)
 740 {
 741         return check_and_freshen(sha1, 0);
 742 }
 743
 744 static void mmap_limit_check(size_t length)
 745 {
 746         static size_t limit = 0;
 747         if (!limit) {
 748                 limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 749                 if (!limit)
 750                         limit = SIZE_MAX;
 751         }
 752         if (length > limit)
 753                 die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 754                     (uintmax_t)length, (uintmax_t)limit);
 755 }
 756
 757 void *xmmap_gently(void *start, size_t length,
 758                   int prot, int flags, int fd, off_t offset)
 759 {
 760         void *ret;
 761
 762         mmap_limit_check(length);
 763         ret = mmap(start, length, prot, flags, fd, offset);
 764         if (ret == MAP_FAILED) {
 765                 if (!length)
 766                         return NULL;
 767                 release_pack_memory(length);
 768                 ret = mmap(start, length, prot, flags, fd, offset);
 769         }
 770         return ret;
 771 }
 772
 773 void *xmmap(void *start, size_t length,
 774         int prot, int flags, int fd, off_t offset)
 775 {
 776         void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 777         if (ret == MAP_FAILED)
 778                 die_errno("mmap failed");
 779         return ret;
 780 }
 781
 782 /*
 783  * With an in-core object data in "map", rehash it to make sure the
 784  * object name actually matches "sha1" to detect object corruption.
 785  * With "map" == NULL, try reading the object named with "sha1" using
 786  * the streaming interface and rehash it to do the same.
 787  */
 788 int check_sha1_signature(const unsigned char *sha1, void *map,
 789                          unsigned long size, const char *type)
 790 {
 791         unsigned char real_sha1[20];
 792         enum object_type obj_type;
 793         struct git_istream *st;
 794         git_SHA_CTX c;
 795         char hdr[32];
 796         int hdrlen;
 797
 798         if (map) {
 799                 hash_sha1_file(map, size, type, real_sha1);
 800                 return hashcmp(sha1, real_sha1) ? -1 : 0;
 801         }
 802
 803         st = open_istream(sha1, &obj_type, &size, NULL);
 804         if (!st)
 805                 return -1;
 806
 807         /* Generate the header */
 808         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 809
 810         /* Sha1.. */
 811         git_SHA1_Init(&c);
 812         git_SHA1_Update(&c, hdr, hdrlen);
 813         for (;;) {
 814                 char buf[1024 * 16];
 815                 ssize_t readlen = read_istream(st, buf, sizeof(buf));
 816
 817                 if (readlen < 0) {
 818                         close_istream(st);
 819                         return -1;
 820                 }
 821                 if (!readlen)
 822                         break;
 823                 git_SHA1_Update(&c, buf, readlen);
 824         }
 825         git_SHA1_Final(real_sha1, &c);
 826         close_istream(st);
 827         return hashcmp(sha1, real_sha1) ? -1 : 0;
 828 }
 829
 830 int git_open_cloexec(const char *name, int flags)
 831 {
 832         int fd;
 833         static int o_cloexec = O_CLOEXEC;
 834
 835         fd = open(name, flags | o_cloexec);
 836         if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 837                 /* Try again w/o O_CLOEXEC: the kernel might not support it */
 838                 o_cloexec &= ~O_CLOEXEC;
 839                 fd = open(name, flags | o_cloexec);
 840         }
 841
 842 #if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 843         {
 844                 static int fd_cloexec = FD_CLOEXEC;
 845
 846                 if (!o_cloexec && 0 <= fd && fd_cloexec) {
 847                         /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 848                         int flags = fcntl(fd, F_GETFD);
 849                         if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 850                                 fd_cloexec = 0;
 851                 }
 852         }
 853 #endif
 854         return fd;
 855 }
 856
 857 /*
 858  * Find "sha1" as a loose object in the local repository or in an alternate.
 859  * Returns 0 on success, negative on failure.
 860  *
 861  * The "path" out-parameter will give the path of the object we found (if any).
 862  * Note that it may point to static storage and is only valid until another
 863  * call to sha1_file_name(), etc.
 864  */
 865 static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 866                           const char **path)
 867 {
 868         struct alternate_object_database *alt;
 869
 870         *path = sha1_file_name(sha1);
 871         if (!lstat(*path, st))
 872                 return 0;
 873
 874         prepare_alt_odb();
 875         errno = ENOENT;
 876         for (alt = alt_odb_list; alt; alt = alt->next) {
 877                 *path = alt_sha1_path(alt, sha1);
 878                 if (!lstat(*path, st))
 879                         return 0;
 880         }
 881
 882         return -1;
 883 }
 884
 885 /*
 886  * Like stat_sha1_file(), but actually open the object and return the
 887  * descriptor. See the caveats on the "path" parameter above.
 888  */
 889 static int open_sha1_file(const unsigned char *sha1, const char **path)
 890 {
 891         int fd;
 892         struct alternate_object_database *alt;
 893         int most_interesting_errno;
 894
 895         *path = sha1_file_name(sha1);
 896         fd = git_open(*path);
 897         if (fd >= 0)
 898                 return fd;
 899         most_interesting_errno = errno;
 900
 901         prepare_alt_odb();
 902         for (alt = alt_odb_list; alt; alt = alt->next) {
 903                 *path = alt_sha1_path(alt, sha1);
 904                 fd = git_open(*path);
 905                 if (fd >= 0)
 906                         return fd;
 907                 if (most_interesting_errno == ENOENT)
 908                         most_interesting_errno = errno;
 909         }
 910         errno = most_interesting_errno;
 911         return -1;
 912 }
 913
 914 /*
 915  * Map the loose object at "path" if it is not NULL, or the path found by
 916  * searching for a loose object named "sha1".
 917  */
 918 static void *map_sha1_file_1(const char *path,
 919                              const unsigned char *sha1,
 920                              unsigned long *size)
 921 {
 922         void *map;
 923         int fd;
 924
 925         if (path)
 926                 fd = git_open(path);
 927         else
 928                 fd = open_sha1_file(sha1, &path);
 929         map = NULL;
 930         if (fd >= 0) {
 931                 struct stat st;
 932
 933                 if (!fstat(fd, &st)) {
 934                         *size = xsize_t(st.st_size);
 935                         if (!*size) {
 936                                 /* mmap() is forbidden on empty files */
 937                                 error("object file %s is empty", path);
 938                                 return NULL;
 939                         }
 940                         map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 941                 }
 942                 close(fd);
 943         }
 944         return map;
 945 }
 946
 947 void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 948 {
 949         return map_sha1_file_1(NULL, sha1, size);
 950 }
 951
 952 static int unpack_sha1_short_header(git_zstream *stream,
 953                                     unsigned char *map, unsigned long mapsize,
 954                                     void *buffer, unsigned long bufsiz)
 955 {
 956         /* Get the data stream */
 957         memset(stream, 0, sizeof(*stream));
 958         stream->next_in = map;
 959         stream->avail_in = mapsize;
 960         stream->next_out = buffer;
 961         stream->avail_out = bufsiz;
 962
 963         git_inflate_init(stream);
 964         return git_inflate(stream, 0);
 965 }
 966
 967 int unpack_sha1_header(git_zstream *stream,
 968                        unsigned char *map, unsigned long mapsize,
 969                        void *buffer, unsigned long bufsiz)
 970 {
 971         int status = unpack_sha1_short_header(stream, map, mapsize,
 972                                               buffer, bufsiz);
 973
 974         if (status < Z_OK)
 975                 return status;
 976
 977         /* Make sure we have the terminating NUL */
 978         if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 979                 return -1;
 980         return 0;
 981 }
 982
 983 static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 984                                         unsigned long mapsize, void *buffer,
 985                                         unsigned long bufsiz, struct strbuf *header)
 986 {
 987         int status;
 988
 989         status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 990         if (status < Z_OK)
 991                 return -1;
 992
 993         /*
 994          * Check if entire header is unpacked in the first iteration.
 995          */
 996         if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 997                 return 0;
 998
 999         /*
1000          * buffer[0..bufsiz] was not large enough.  Copy the partial
1001          * result out to header, and then append the result of further
1002          * reading the stream.
1003          */
1004         strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1005         stream->next_out = buffer;
1006         stream->avail_out = bufsiz;
1007
1008         do {
1009                 status = git_inflate(stream, 0);
1010                 strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1011                 if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1012                         return 0;
1013                 stream->next_out = buffer;
1014                 stream->avail_out = bufsiz;
1015         } while (status != Z_STREAM_END);
1016         return -1;
1017 }
1018
1019 static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1020 {
1021         int bytes = strlen(buffer) + 1;
1022         unsigned char *buf = xmallocz(size);
1023         unsigned long n;
1024         int status = Z_OK;
1025
1026         n = stream->total_out - bytes;
1027         if (n > size)
1028                 n = size;
1029         memcpy(buf, (char *) buffer + bytes, n);
1030         bytes = n;
1031         if (bytes <= size) {
1032                 /*
1033                  * The above condition must be (bytes <= size), not
1034                  * (bytes < size).  In other words, even though we
1035                  * expect no more output and set avail_out to zero,
1036                  * the input zlib stream may have bytes that express
1037                  * "this concludes the stream", and we *do* want to
1038                  * eat that input.
1039                  *
1040                  * Otherwise we would not be able to test that we
1041                  * consumed all the input to reach the expected size;
1042                  * we also want to check that zlib tells us that all
1043                  * went well with status == Z_STREAM_END at the end.
1044                  */
1045                 stream->next_out = buf + bytes;
1046                 stream->avail_out = size - bytes;
1047                 while (status == Z_OK)
1048                         status = git_inflate(stream, Z_FINISH);
1049         }
1050         if (status == Z_STREAM_END && !stream->avail_in) {
1051                 git_inflate_end(stream);
1052                 return buf;
1053         }
1054
1055         if (status < 0)
1056                 error("corrupt loose object '%s'", sha1_to_hex(sha1));
1057         else if (stream->avail_in)
1058                 error("garbage at end of loose object '%s'",
1059                       sha1_to_hex(sha1));
1060         free(buf);
1061         return NULL;
1062 }
1063
1064 /*
1065  * We used to just use "sscanf()", but that's actually way
1066  * too permissive for what we want to check. So do an anal
1067  * object header parse by hand.
1068  */
1069 static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1070                                unsigned int flags)
1071 {
1072         const char *type_buf = hdr;
1073         unsigned long size;
1074         int type, type_len = 0;
1075
1076         /*
1077          * The type can be of any size but is followed by
1078          * a space.
1079          */
1080         for (;;) {
1081                 char c = *hdr++;
1082                 if (!c)
1083                         return -1;
1084                 if (c == ' ')
1085                         break;
1086                 type_len++;
1087         }
1088
1089         type = type_from_string_gently(type_buf, type_len, 1);
1090         if (oi->typename)
1091                 strbuf_add(oi->typename, type_buf, type_len);
1092         /*
1093          * Set type to 0 if its an unknown object and
1094          * we're obtaining the type using '--allow-unknown-type'
1095          * option.
1096          */
1097         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1098                 type = 0;
1099         else if (type < 0)
1100                 die("invalid object type");
1101         if (oi->typep)
1102                 *oi->typep = type;
1103
1104         /*
1105          * The length must follow immediately, and be in canonical
1106          * decimal format (ie "010" is not valid).
1107          */
1108         size = *hdr++ - '0';
1109         if (size > 9)
1110                 return -1;
1111         if (size) {
1112                 for (;;) {
1113                         unsigned long c = *hdr - '0';
1114                         if (c > 9)
1115                                 break;
1116                         hdr++;
1117                         size = size * 10 + c;
1118                 }
1119         }
1120
1121         if (oi->sizep)
1122                 *oi->sizep = size;
1123
1124         /*
1125          * The length must be followed by a zero byte
1126          */
1127         return *hdr ? -1 : type;
1128 }
1129
1130 int parse_sha1_header(const char *hdr, unsigned long *sizep)
1131 {
1132         struct object_info oi = OBJECT_INFO_INIT;
1133
1134         oi.sizep = sizep;
1135         return parse_sha1_header_extended(hdr, &oi, 0);
1136 }
1137
1138 static int sha1_loose_object_info(const unsigned char *sha1,
1139                                   struct object_info *oi,
1140                                   int flags)
1141 {
1142         int status = 0;
1143         unsigned long mapsize;
1144         void *map;
1145         git_zstream stream;
1146         char hdr[32];
1147         struct strbuf hdrbuf = STRBUF_INIT;
1148         unsigned long size_scratch;
1149
1150         if (oi->delta_base_sha1)
1151                 hashclr(oi->delta_base_sha1);
1152
1153         /*
1154          * If we don't care about type or size, then we don't
1155          * need to look inside the object at all. Note that we
1156          * do not optimize out the stat call, even if the
1157          * caller doesn't care about the disk-size, since our
1158          * return value implicitly indicates whether the
1159          * object even exists.
1160          */
1161         if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1162                 const char *path;
1163                 struct stat st;
1164                 if (stat_sha1_file(sha1, &st, &path) < 0)
1165                         return -1;
1166                 if (oi->disk_sizep)
1167                         *oi->disk_sizep = st.st_size;
1168                 return 0;
1169         }
1170
1171         map = map_sha1_file(sha1, &mapsize);
1172         if (!map)
1173                 return -1;
1174
1175         if (!oi->sizep)
1176                 oi->sizep = &size_scratch;
1177
1178         if (oi->disk_sizep)
1179                 *oi->disk_sizep = mapsize;
1180         if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1181                 if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1182                         status = error("unable to unpack %s header with --allow-unknown-type",
1183                                        sha1_to_hex(sha1));
1184         } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1185                 status = error("unable to unpack %s header",
1186                                sha1_to_hex(sha1));
1187         if (status < 0)
1188                 ; /* Do nothing */
1189         else if (hdrbuf.len) {
1190                 if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1191                         status = error("unable to parse %s header with --allow-unknown-type",
1192                                        sha1_to_hex(sha1));
1193         } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1194                 status = error("unable to parse %s header", sha1_to_hex(sha1));
1195
1196         if (status >= 0 && oi->contentp) {
1197                 *oi->contentp = unpack_sha1_rest(&stream, hdr,
1198                                                  *oi->sizep, sha1);
1199                 if (!*oi->contentp) {
1200                         git_inflate_end(&stream);
1201                         status = -1;
1202                 }
1203         } else
1204                 git_inflate_end(&stream);
1205
1206         munmap(map, mapsize);
1207         if (status && oi->typep)
1208                 *oi->typep = status;
1209         if (oi->sizep == &size_scratch)
1210                 oi->sizep = NULL;
1211         strbuf_release(&hdrbuf);
1212         oi->whence = OI_LOOSE;
1213         return (status < 0) ? status : 0;
1214 }
1215
1216 int fetch_if_missing = 1;
1217
1218 int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1219 {
1220         static struct object_info blank_oi = OBJECT_INFO_INIT;
1221         struct pack_entry e;
1222         int rtype;
1223         const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1224                                     lookup_replace_object(sha1) :
1225                                     sha1;
1226         int already_retried = 0;
1227
1228         if (is_null_sha1(real))
1229                 return -1;
1230
1231         if (!oi)
1232                 oi = &blank_oi;
1233
1234         if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1235                 struct cached_object *co = find_cached_object(real);
1236                 if (co) {
1237                         if (oi->typep)
1238                                 *(oi->typep) = co->type;
1239                         if (oi->sizep)
1240                                 *(oi->sizep) = co->size;
1241                         if (oi->disk_sizep)
1242                                 *(oi->disk_sizep) = 0;
1243                         if (oi->delta_base_sha1)
1244                                 hashclr(oi->delta_base_sha1);
1245                         if (oi->typename)
1246                                 strbuf_addstr(oi->typename, typename(co->type));
1247                         if (oi->contentp)
1248                                 *oi->contentp = xmemdupz(co->buf, co->size);
1249                         oi->whence = OI_CACHED;
1250                         return 0;
1251                 }
1252         }
1253
1254         while (1) {
1255                 if (find_pack_entry(real, &e))
1256                         break;
1257
1258                 /* Most likely it's a loose object. */
1259                 if (!sha1_loose_object_info(real, oi, flags))
1260                         return 0;
1261
1262                 /* Not a loose object; someone else may have just packed it. */
1263                 reprepare_packed_git();
1264                 if (find_pack_entry(real, &e))
1265                         break;
1266
1267                 /* Check if it is a missing object */
1268                 if (fetch_if_missing && repository_format_partial_clone &&
1269                     !already_retried) {
1270                         /*
1271                          * TODO Investigate haveing fetch_object() return
1272                          * TODO error/success and stopping the music here.
1273                          */
1274                         fetch_object(repository_format_partial_clone, real);
1275                         already_retried = 1;
1276                         continue;
1277                 }
1278
1279                 return -1;
1280         }
1281
1282         if (oi == &blank_oi)
1283                 /*
1284                  * We know that the caller doesn't actually need the
1285                  * information below, so return early.
1286                  */
1287                 return 0;
1288         rtype = packed_object_info(e.p, e.offset, oi);
1289         if (rtype < 0) {
1290                 mark_bad_packed_object(e.p, real);
1291                 return sha1_object_info_extended(real, oi, 0);
1292         } else if (oi->whence == OI_PACKED) {
1293                 oi->u.packed.offset = e.offset;
1294                 oi->u.packed.pack = e.p;
1295                 oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1296                                          rtype == OBJ_OFS_DELTA);
1297         }
1298
1299         return 0;
1300 }
1301
1302 /* returns enum object_type or negative */
1303 int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1304 {
1305         enum object_type type;
1306         struct object_info oi = OBJECT_INFO_INIT;
1307
1308         oi.typep = &type;
1309         oi.sizep = sizep;
1310         if (sha1_object_info_extended(sha1, &oi,
1311                                       OBJECT_INFO_LOOKUP_REPLACE) < 0)
1312                 return -1;
1313         return type;
1314 }
1315
1316 static void *read_object(const unsigned char *sha1, enum object_type *type,
1317                          unsigned long *size)
1318 {
1319         struct object_info oi = OBJECT_INFO_INIT;
1320         void *content;
1321         oi.typep = type;
1322         oi.sizep = size;
1323         oi.contentp = &content;
1324
1325         if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1326                 return NULL;
1327         return content;
1328 }
1329
1330 int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1331                       unsigned char *sha1)
1332 {
1333         struct cached_object *co;
1334
1335         hash_sha1_file(buf, len, typename(type), sha1);
1336         if (has_sha1_file(sha1) || find_cached_object(sha1))
1337                 return 0;
1338         ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1339         co = &cached_objects[cached_object_nr++];
1340         co->size = len;
1341         co->type = type;
1342         co->buf = xmalloc(len);
1343         memcpy(co->buf, buf, len);
1344         hashcpy(co->sha1, sha1);
1345         return 0;
1346 }
1347
1348 /*
1349  * This function dies on corrupt objects; the callers who want to
1350  * deal with them should arrange to call read_object() and give error
1351  * messages themselves.
1352  */
1353 void *read_sha1_file_extended(const unsigned char *sha1,
1354                               enum object_type *type,
1355                               unsigned long *size,
1356                               int lookup_replace)
1357 {
1358         void *data;
1359         const struct packed_git *p;
1360         const char *path;
1361         struct stat st;
1362         const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1363                                                    : sha1;
1364
1365         errno = 0;
1366         data = read_object(repl, type, size);
1367         if (data)
1368                 return data;
1369
1370         if (errno && errno != ENOENT)
1371                 die_errno("failed to read object %s", sha1_to_hex(sha1));
1372
1373         /* die if we replaced an object with one that does not exist */
1374         if (repl != sha1)
1375                 die("replacement %s not found for %s",
1376                     sha1_to_hex(repl), sha1_to_hex(sha1));
1377
1378         if (!stat_sha1_file(repl, &st, &path))
1379                 die("loose object %s (stored in %s) is corrupt",
1380                     sha1_to_hex(repl), path);
1381
1382         if ((p = has_packed_and_bad(repl)) != NULL)
1383                 die("packed object %s (stored in %s) is corrupt",
1384                     sha1_to_hex(repl), p->pack_name);
1385
1386         return NULL;
1387 }
1388
1389 void *read_object_with_reference(const unsigned char *sha1,
1390                                  const char *required_type_name,
1391                                  unsigned long *size,
1392                                  unsigned char *actual_sha1_return)
1393 {
1394         enum object_type type, required_type;
1395         void *buffer;
1396         unsigned long isize;
1397         unsigned char actual_sha1[20];
1398
1399         required_type = type_from_string(required_type_name);
1400         hashcpy(actual_sha1, sha1);
1401         while (1) {
1402                 int ref_length = -1;
1403                 const char *ref_type = NULL;
1404
1405                 buffer = read_sha1_file(actual_sha1, &type, &isize);
1406                 if (!buffer)
1407                         return NULL;
1408                 if (type == required_type) {
1409                         *size = isize;
1410                         if (actual_sha1_return)
1411                                 hashcpy(actual_sha1_return, actual_sha1);
1412                         return buffer;
1413                 }
1414                 /* Handle references */
1415                 else if (type == OBJ_COMMIT)
1416                         ref_type = "tree ";
1417                 else if (type == OBJ_TAG)
1418                         ref_type = "object ";
1419                 else {
1420                         free(buffer);
1421                         return NULL;
1422                 }
1423                 ref_length = strlen(ref_type);
1424
1425                 if (ref_length + 40 > isize ||
1426                     memcmp(buffer, ref_type, ref_length) ||
1427                     get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1428                         free(buffer);
1429                         return NULL;
1430                 }
1431                 free(buffer);
1432                 /* Now we have the ID of the referred-to object in
1433                  * actual_sha1.  Check again. */
1434         }
1435 }
1436
1437 static void write_sha1_file_prepare(const void *buf, unsigned long len,
1438                                     const char *type, unsigned char *sha1,
1439                                     char *hdr, int *hdrlen)
1440 {
1441         git_SHA_CTX c;
1442
1443         /* Generate the header */
1444         *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1445
1446         /* Sha1.. */
1447         git_SHA1_Init(&c);
1448         git_SHA1_Update(&c, hdr, *hdrlen);
1449         git_SHA1_Update(&c, buf, len);
1450         git_SHA1_Final(sha1, &c);
1451 }
1452
1453 /*
1454  * Move the just written object into its final resting place.
1455  */
1456 int finalize_object_file(const char *tmpfile, const char *filename)
1457 {
1458         int ret = 0;
1459
1460         if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1461                 goto try_rename;
1462         else if (link(tmpfile, filename))
1463                 ret = errno;
1464
1465         /*
1466          * Coda hack - coda doesn't like cross-directory links,
1467          * so we fall back to a rename, which will mean that it
1468          * won't be able to check collisions, but that's not a
1469          * big deal.
1470          *
1471          * The same holds for FAT formatted media.
1472          *
1473          * When this succeeds, we just return.  We have nothing
1474          * left to unlink.
1475          */
1476         if (ret && ret != EEXIST) {
1477         try_rename:
1478                 if (!rename(tmpfile, filename))
1479                         goto out;
1480                 ret = errno;
1481         }
1482         unlink_or_warn(tmpfile);
1483         if (ret) {
1484                 if (ret != EEXIST) {
1485                         return error_errno("unable to write sha1 filename %s", filename);
1486                 }
1487                 /* FIXME!!! Collision check here ? */
1488         }
1489
1490 out:
1491         if (adjust_shared_perm(filename))
1492                 return error("unable to set permission to '%s'", filename);
1493         return 0;
1494 }
1495
1496 static int write_buffer(int fd, const void *buf, size_t len)
1497 {
1498         if (write_in_full(fd, buf, len) < 0)
1499                 return error_errno("file write error");
1500         return 0;
1501 }
1502
1503 int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1504                    unsigned char *sha1)
1505 {
1506         char hdr[32];
1507         int hdrlen = sizeof(hdr);
1508         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1509         return 0;
1510 }
1511
1512 /* Finalize a file on disk, and close it. */
1513 static void close_sha1_file(int fd)
1514 {
1515         if (fsync_object_files)
1516                 fsync_or_die(fd, "sha1 file");
1517         if (close(fd) != 0)
1518                 die_errno("error when closing sha1 file");
1519 }
1520
1521 /* Size of directory component, including the ending '/' */
1522 static inline int directory_size(const char *filename)
1523 {
1524         const char *s = strrchr(filename, '/');
1525         if (!s)
1526                 return 0;
1527         return s - filename + 1;
1528 }
1529
1530 /*
1531  * This creates a temporary file in the same directory as the final
1532  * 'filename'
1533  *
1534  * We want to avoid cross-directory filename renames, because those
1535  * can have problems on various filesystems (FAT, NFS, Coda).
1536  */
1537 static int create_tmpfile(struct strbuf *tmp, const char *filename)
1538 {
1539         int fd, dirlen = directory_size(filename);
1540
1541         strbuf_reset(tmp);
1542         strbuf_add(tmp, filename, dirlen);
1543         strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1544         fd = git_mkstemp_mode(tmp->buf, 0444);
1545         if (fd < 0 && dirlen && errno == ENOENT) {
1546                 /*
1547                  * Make sure the directory exists; note that the contents
1548                  * of the buffer are undefined after mkstemp returns an
1549                  * error, so we have to rewrite the whole buffer from
1550                  * scratch.
1551                  */
1552                 strbuf_reset(tmp);
1553                 strbuf_add(tmp, filename, dirlen - 1);
1554                 if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1555                         return -1;
1556                 if (adjust_shared_perm(tmp->buf))
1557                         return -1;
1558
1559                 /* Try again */
1560                 strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1561                 fd = git_mkstemp_mode(tmp->buf, 0444);
1562         }
1563         return fd;
1564 }
1565
1566 static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1567                               const void *buf, unsigned long len, time_t mtime)
1568 {
1569         int fd, ret;
1570         unsigned char compressed[4096];
1571         git_zstream stream;
1572         git_SHA_CTX c;
1573         unsigned char parano_sha1[20];
1574         static struct strbuf tmp_file = STRBUF_INIT;
1575         const char *filename = sha1_file_name(sha1);
1576
1577         fd = create_tmpfile(&tmp_file, filename);
1578         if (fd < 0) {
1579                 if (errno == EACCES)
1580                         return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1581                 else
1582                         return error_errno("unable to create temporary file");
1583         }
1584
1585         /* Set it up */
1586         git_deflate_init(&stream, zlib_compression_level);
1587         stream.next_out = compressed;
1588         stream.avail_out = sizeof(compressed);
1589         git_SHA1_Init(&c);
1590
1591         /* First header.. */
1592         stream.next_in = (unsigned char *)hdr;
1593         stream.avail_in = hdrlen;
1594         while (git_deflate(&stream, 0) == Z_OK)
1595                 ; /* nothing */
1596         git_SHA1_Update(&c, hdr, hdrlen);
1597
1598         /* Then the data itself.. */
1599         stream.next_in = (void *)buf;
1600         stream.avail_in = len;
1601         do {
1602                 unsigned char *in0 = stream.next_in;
1603                 ret = git_deflate(&stream, Z_FINISH);
1604                 git_SHA1_Update(&c, in0, stream.next_in - in0);
1605                 if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1606                         die("unable to write sha1 file");
1607                 stream.next_out = compressed;
1608                 stream.avail_out = sizeof(compressed);
1609         } while (ret == Z_OK);
1610
1611         if (ret != Z_STREAM_END)
1612                 die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1613         ret = git_deflate_end_gently(&stream);
1614         if (ret != Z_OK)
1615                 die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1616         git_SHA1_Final(parano_sha1, &c);
1617         if (hashcmp(sha1, parano_sha1) != 0)
1618                 die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1619
1620         close_sha1_file(fd);
1621
1622         if (mtime) {
1623                 struct utimbuf utb;
1624                 utb.actime = mtime;
1625                 utb.modtime = mtime;
1626                 if (utime(tmp_file.buf, &utb) < 0)
1627                         warning_errno("failed utime() on %s", tmp_file.buf);
1628         }
1629
1630         return finalize_object_file(tmp_file.buf, filename);
1631 }
1632
1633 static int freshen_loose_object(const unsigned char *sha1)
1634 {
1635         return check_and_freshen(sha1, 1);
1636 }
1637
1638 static int freshen_packed_object(const unsigned char *sha1)
1639 {
1640         struct pack_entry e;
1641         if (!find_pack_entry(sha1, &e))
1642                 return 0;
1643         if (e.p->freshened)
1644                 return 1;
1645         if (!freshen_file(e.p->pack_name))
1646                 return 0;
1647         e.p->freshened = 1;
1648         return 1;
1649 }
1650
1651 int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1652 {
1653         char hdr[32];
1654         int hdrlen = sizeof(hdr);
1655
1656         /* Normally if we have it in the pack then we do not bother writing
1657          * it out into .git/objects/??/?{38} file.
1658          */
1659         write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1660         if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1661                 return 0;
1662         return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1663 }
1664
1665 int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1666                              struct object_id *oid, unsigned flags)
1667 {
1668         char *header;
1669         int hdrlen, status = 0;
1670
1671         /* type string, SP, %lu of the length plus NUL must fit this */
1672         hdrlen = strlen(type) + 32;
1673         header = xmalloc(hdrlen);
1674         write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1675
1676         if (!(flags & HASH_WRITE_OBJECT))
1677                 goto cleanup;
1678         if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1679                 goto cleanup;
1680         status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1681
1682 cleanup:
1683         free(header);
1684         return status;
1685 }
1686
1687 int force_object_loose(const unsigned char *sha1, time_t mtime)
1688 {
1689         void *buf;
1690         unsigned long len;
1691         enum object_type type;
1692         char hdr[32];
1693         int hdrlen;
1694         int ret;
1695
1696         if (has_loose_object(sha1))
1697                 return 0;
1698         buf = read_object(sha1, &type, &len);
1699         if (!buf)
1700                 return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1701         hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1702         ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1703         free(buf);
1704
1705         return ret;
1706 }
1707
1708 int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1709 {
1710         if (!startup_info->have_repository)
1711                 return 0;
1712         return sha1_object_info_extended(sha1, NULL,
1713                                          flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1714 }
1715
1716 int has_object_file(const struct object_id *oid)
1717 {
1718         return has_sha1_file(oid->hash);
1719 }
1720
1721 int has_object_file_with_flags(const struct object_id *oid, int flags)
1722 {
1723         return has_sha1_file_with_flags(oid->hash, flags);
1724 }
1725
1726 static void check_tree(const void *buf, size_t size)
1727 {
1728         struct tree_desc desc;
1729         struct name_entry entry;
1730
1731         init_tree_desc(&desc, buf, size);
1732         while (tree_entry(&desc, &entry))
1733                 /* do nothing
1734                  * tree_entry() will die() on malformed entries */
1735                 ;
1736 }
1737
1738 static void check_commit(const void *buf, size_t size)
1739 {
1740         struct commit c;
1741         memset(&c, 0, sizeof(c));
1742         if (parse_commit_buffer(&c, buf, size))
1743                 die("corrupt commit");
1744 }
1745
1746 static void check_tag(const void *buf, size_t size)
1747 {
1748         struct tag t;
1749         memset(&t, 0, sizeof(t));
1750         if (parse_tag_buffer(&t, buf, size))
1751                 die("corrupt tag");
1752 }
1753
1754 static int index_mem(struct object_id *oid, void *buf, size_t size,
1755                      enum object_type type,
1756                      const char *path, unsigned flags)
1757 {
1758         int ret, re_allocated = 0;
1759         int write_object = flags & HASH_WRITE_OBJECT;
1760
1761         if (!type)
1762                 type = OBJ_BLOB;
1763
1764         /*
1765          * Convert blobs to git internal format
1766          */
1767         if ((type == OBJ_BLOB) && path) {
1768                 struct strbuf nbuf = STRBUF_INIT;
1769                 if (convert_to_git(&the_index, path, buf, size, &nbuf,
1770                                    get_conv_flags(flags))) {
1771                         buf = strbuf_detach(&nbuf, &size);
1772                         re_allocated = 1;
1773                 }
1774         }
1775         if (flags & HASH_FORMAT_CHECK) {
1776                 if (type == OBJ_TREE)
1777                         check_tree(buf, size);
1778                 if (type == OBJ_COMMIT)
1779                         check_commit(buf, size);
1780                 if (type == OBJ_TAG)
1781                         check_tag(buf, size);
1782         }
1783
1784         if (write_object)
1785                 ret = write_sha1_file(buf, size, typename(type), oid->hash);
1786         else
1787                 ret = hash_sha1_file(buf, size, typename(type), oid->hash);
1788         if (re_allocated)
1789                 free(buf);
1790         return ret;
1791 }
1792
1793 static int index_stream_convert_blob(struct object_id *oid, int fd,
1794                                      const char *path, unsigned flags)
1795 {
1796         int ret;
1797         const int write_object = flags & HASH_WRITE_OBJECT;
1798         struct strbuf sbuf = STRBUF_INIT;
1799
1800         assert(path);
1801         assert(would_convert_to_git_filter_fd(path));
1802
1803         convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1804                                  get_conv_flags(flags));
1805
1806         if (write_object)
1807                 ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1808                                       oid->hash);
1809         else
1810                 ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1811                                      oid->hash);
1812         strbuf_release(&sbuf);
1813         return ret;
1814 }
1815
1816 static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1817                       const char *path, unsigned flags)
1818 {
1819         struct strbuf sbuf = STRBUF_INIT;
1820         int ret;
1821
1822         if (strbuf_read(&sbuf, fd, 4096) >= 0)
1823                 ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1824         else
1825                 ret = -1;
1826         strbuf_release(&sbuf);
1827         return ret;
1828 }
1829
1830 #define SMALL_FILE_SIZE (32*1024)
1831
1832 static int index_core(struct object_id *oid, int fd, size_t size,
1833                       enum object_type type, const char *path,
1834                       unsigned flags)
1835 {
1836         int ret;
1837
1838         if (!size) {
1839                 ret = index_mem(oid, "", size, type, path, flags);
1840         } else if (size <= SMALL_FILE_SIZE) {
1841                 char *buf = xmalloc(size);
1842                 ssize_t read_result = read_in_full(fd, buf, size);
1843                 if (read_result < 0)
1844                         ret = error_errno("read error while indexing %s",
1845                                           path ? path : "<unknown>");
1846                 else if (read_result != size)
1847                         ret = error("short read while indexing %s",
1848                                     path ? path : "<unknown>");
1849                 else
1850                         ret = index_mem(oid, buf, size, type, path, flags);
1851                 free(buf);
1852         } else {
1853                 void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1854                 ret = index_mem(oid, buf, size, type, path, flags);
1855                 munmap(buf, size);
1856         }
1857         return ret;
1858 }
1859
1860 /*
1861  * This creates one packfile per large blob unless bulk-checkin
1862  * machinery is "plugged".
1863  *
1864  * This also bypasses the usual "convert-to-git" dance, and that is on
1865  * purpose. We could write a streaming version of the converting
1866  * functions and insert that before feeding the data to fast-import
1867  * (or equivalent in-core API described above). However, that is
1868  * somewhat complicated, as we do not know the size of the filter
1869  * result, which we need to know beforehand when writing a git object.
1870  * Since the primary motivation for trying to stream from the working
1871  * tree file and to avoid mmaping it in core is to deal with large
1872  * binary blobs, they generally do not want to get any conversion, and
1873  * callers should avoid this code path when filters are requested.
1874  */
1875 static int index_stream(struct object_id *oid, int fd, size_t size,
1876                         enum object_type type, const char *path,
1877                         unsigned flags)
1878 {
1879         return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1880 }
1881
1882 int index_fd(struct object_id *oid, int fd, struct stat *st,
1883              enum object_type type, const char *path, unsigned flags)
1884 {
1885         int ret;
1886
1887         /*
1888          * Call xsize_t() only when needed to avoid potentially unnecessary
1889          * die() for large files.
1890          */
1891         if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1892                 ret = index_stream_convert_blob(oid, fd, path, flags);
1893         else if (!S_ISREG(st->st_mode))
1894                 ret = index_pipe(oid, fd, type, path, flags);
1895         else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1896                  (path && would_convert_to_git(&the_index, path)))
1897                 ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1898                                  flags);
1899         else
1900                 ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1901                                    flags);
1902         close(fd);
1903         return ret;
1904 }
1905
1906 int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1907 {
1908         int fd;
1909         struct strbuf sb = STRBUF_INIT;
1910         int rc = 0;
1911
1912         switch (st->st_mode & S_IFMT) {
1913         case S_IFREG:
1914                 fd = open(path, O_RDONLY);
1915                 if (fd < 0)
1916                         return error_errno("open(\"%s\")", path);
1917                 if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1918                         return error("%s: failed to insert into database",
1919                                      path);
1920                 break;
1921         case S_IFLNK:
1922                 if (strbuf_readlink(&sb, path, st->st_size))
1923                         return error_errno("readlink(\"%s\")", path);
1924                 if (!(flags & HASH_WRITE_OBJECT))
1925                         hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1926                 else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1927                         rc = error("%s: failed to insert into database", path);
1928                 strbuf_release(&sb);
1929                 break;
1930         case S_IFDIR:
1931                 return resolve_gitlink_ref(path, "HEAD", oid);
1932         default:
1933                 return error("%s: unsupported file type", path);
1934         }
1935         return rc;
1936 }
1937
1938 int read_pack_header(int fd, struct pack_header *header)
1939 {
1940         if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1941                 /* "eof before pack header was fully read" */
1942                 return PH_ERROR_EOF;
1943
1944         if (header->hdr_signature != htonl(PACK_SIGNATURE))
1945                 /* "protocol error (pack signature mismatch detected)" */
1946                 return PH_ERROR_PACK_SIGNATURE;
1947         if (!pack_version_ok(header->hdr_version))
1948                 /* "protocol error (pack version unsupported)" */
1949                 return PH_ERROR_PROTOCOL;
1950         return 0;
1951 }
1952
1953 void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1954 {
1955         enum object_type type = sha1_object_info(sha1, NULL);
1956         if (type < 0)
1957                 die("%s is not a valid object", sha1_to_hex(sha1));
1958         if (type != expect)
1959                 die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1960                     typename(expect));
1961 }
1962
1963 int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1964                                 struct strbuf *path,
1965                                 each_loose_object_fn obj_cb,
1966                                 each_loose_cruft_fn cruft_cb,
1967                                 each_loose_subdir_fn subdir_cb,
1968                                 void *data)
1969 {
1970         size_t origlen, baselen;
1971         DIR *dir;
1972         struct dirent *de;
1973         int r = 0;
1974         struct object_id oid;
1975
1976         if (subdir_nr > 0xff)
1977                 BUG("invalid loose object subdirectory: %x", subdir_nr);
1978
1979         origlen = path->len;
1980         strbuf_complete(path, '/');
1981         strbuf_addf(path, "%02x", subdir_nr);
1982
1983         dir = opendir(path->buf);
1984         if (!dir) {
1985                 if (errno != ENOENT)
1986                         r = error_errno("unable to open %s", path->buf);
1987                 strbuf_setlen(path, origlen);
1988                 return r;
1989         }
1990
1991         oid.hash[0] = subdir_nr;
1992         strbuf_addch(path, '/');
1993         baselen = path->len;
1994
1995         while ((de = readdir(dir))) {
1996                 size_t namelen;
1997                 if (is_dot_or_dotdot(de->d_name))
1998                         continue;
1999
2000                 namelen = strlen(de->d_name);
2001                 strbuf_setlen(path, baselen);
2002                 strbuf_add(path, de->d_name, namelen);
2003                 if (namelen == GIT_SHA1_HEXSZ - 2 &&
2004                     !hex_to_bytes(oid.hash + 1, de->d_name,
2005                                   GIT_SHA1_RAWSZ - 1)) {
2006                         if (obj_cb) {
2007                                 r = obj_cb(&oid, path->buf, data);
2008                                 if (r)
2009                                         break;
2010                         }
2011                         continue;
2012                 }
2013
2014                 if (cruft_cb) {
2015                         r = cruft_cb(de->d_name, path->buf, data);
2016                         if (r)
2017                                 break;
2018                 }
2019         }
2020         closedir(dir);
2021
2022         strbuf_setlen(path, baselen - 1);
2023         if (!r && subdir_cb)
2024                 r = subdir_cb(subdir_nr, path->buf, data);
2025
2026         strbuf_setlen(path, origlen);
2027
2028         return r;
2029 }
2030
2031 int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2032                             each_loose_object_fn obj_cb,
2033                             each_loose_cruft_fn cruft_cb,
2034                             each_loose_subdir_fn subdir_cb,
2035                             void *data)
2036 {
2037         int r = 0;
2038         int i;
2039
2040         for (i = 0; i < 256; i++) {
2041                 r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2042                                                 subdir_cb, data);
2043                 if (r)
2044                         break;
2045         }
2046
2047         return r;
2048 }
2049
2050 int for_each_loose_file_in_objdir(const char *path,
2051                                   each_loose_object_fn obj_cb,
2052                                   each_loose_cruft_fn cruft_cb,
2053                                   each_loose_subdir_fn subdir_cb,
2054                                   void *data)
2055 {
2056         struct strbuf buf = STRBUF_INIT;
2057         int r;
2058
2059         strbuf_addstr(&buf, path);
2060         r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2061                                               subdir_cb, data);
2062         strbuf_release(&buf);
2063
2064         return r;
2065 }
2066
2067 struct loose_alt_odb_data {
2068         each_loose_object_fn *cb;
2069         void *data;
2070 };
2071
2072 static int loose_from_alt_odb(struct alternate_object_database *alt,
2073                               void *vdata)
2074 {
2075         struct loose_alt_odb_data *data = vdata;
2076         struct strbuf buf = STRBUF_INIT;
2077         int r;
2078
2079         strbuf_addstr(&buf, alt->path);
2080         r = for_each_loose_file_in_objdir_buf(&buf,
2081                                               data->cb, NULL, NULL,
2082                                               data->data);
2083         strbuf_release(&buf);
2084         return r;
2085 }
2086
2087 int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2088 {
2089         struct loose_alt_odb_data alt;
2090         int r;
2091
2092         r = for_each_loose_file_in_objdir(get_object_directory(),
2093                                           cb, NULL, NULL, data);
2094         if (r)
2095                 return r;
2096
2097         if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2098                 return 0;
2099
2100         alt.cb = cb;
2101         alt.data = data;
2102         return foreach_alt_odb(loose_from_alt_odb, &alt);
2103 }
2104
2105 static int check_stream_sha1(git_zstream *stream,
2106                              const char *hdr,
2107                              unsigned long size,
2108                              const char *path,
2109                              const unsigned char *expected_sha1)
2110 {
2111         git_SHA_CTX c;
2112         unsigned char real_sha1[GIT_MAX_RAWSZ];
2113         unsigned char buf[4096];
2114         unsigned long total_read;
2115         int status = Z_OK;
2116
2117         git_SHA1_Init(&c);
2118         git_SHA1_Update(&c, hdr, stream->total_out);
2119
2120         /*
2121          * We already read some bytes into hdr, but the ones up to the NUL
2122          * do not count against the object's content size.
2123          */
2124         total_read = stream->total_out - strlen(hdr) - 1;
2125
2126         /*
2127          * This size comparison must be "<=" to read the final zlib packets;
2128          * see the comment in unpack_sha1_rest for details.
2129          */
2130         while (total_read <= size &&
2131                (status == Z_OK || status == Z_BUF_ERROR)) {
2132                 stream->next_out = buf;
2133                 stream->avail_out = sizeof(buf);
2134                 if (size - total_read < stream->avail_out)
2135                         stream->avail_out = size - total_read;
2136                 status = git_inflate(stream, Z_FINISH);
2137                 git_SHA1_Update(&c, buf, stream->next_out - buf);
2138                 total_read += stream->next_out - buf;
2139         }
2140         git_inflate_end(stream);
2141
2142         if (status != Z_STREAM_END) {
2143                 error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2144                 return -1;
2145         }
2146         if (stream->avail_in) {
2147                 error("garbage at end of loose object '%s'",
2148                       sha1_to_hex(expected_sha1));
2149                 return -1;
2150         }
2151
2152         git_SHA1_Final(real_sha1, &c);
2153         if (hashcmp(expected_sha1, real_sha1)) {
2154                 error("sha1 mismatch for %s (expected %s)", path,
2155                       sha1_to_hex(expected_sha1));
2156                 return -1;
2157         }
2158
2159         return 0;
2160 }
2161
2162 int read_loose_object(const char *path,
2163                       const unsigned char *expected_sha1,
2164                       enum object_type *type,
2165                       unsigned long *size,
2166                       void **contents)
2167 {
2168         int ret = -1;
2169         void *map = NULL;
2170         unsigned long mapsize;
2171         git_zstream stream;
2172         char hdr[32];
2173
2174         *contents = NULL;
2175
2176         map = map_sha1_file_1(path, NULL, &mapsize);
2177         if (!map) {
2178                 error_errno("unable to mmap %s", path);
2179                 goto out;
2180         }
2181
2182         if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2183                 error("unable to unpack header of %s", path);
2184                 goto out;
2185         }
2186
2187         *type = parse_sha1_header(hdr, size);
2188         if (*type < 0) {
2189                 error("unable to parse header of %s", path);
2190                 git_inflate_end(&stream);
2191                 goto out;
2192         }
2193
2194         if (*type == OBJ_BLOB) {
2195                 if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2196                         goto out;
2197         } else {
2198                 *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2199                 if (!*contents) {
2200                         error("unable to unpack contents of %s", path);
2201                         git_inflate_end(&stream);
2202                         goto out;
2203                 }
2204                 if (check_sha1_signature(expected_sha1, *contents,
2205                                          *size, typename(*type))) {
2206                         error("sha1 mismatch for %s (expected %s)", path,
2207                               sha1_to_hex(expected_sha1));
2208                         free(*contents);
2209                         goto out;
2210                 }
2211         }
2212
2213         ret = 0; /* everything checks out */
2214
2215 out:
2216         if (map)
2217                 munmap(map, mapsize);
2218         return ret;
2219 }