sha1_file.con commit Convert find_unique_abbrev* to struct object_id (aab9583)
   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
  33const unsigned char null_sha1[GIT_MAX_RAWSZ];
  34const struct object_id null_oid;
  35const struct object_id empty_tree_oid = {
  36        EMPTY_TREE_SHA1_BIN_LITERAL
  37};
  38const struct object_id empty_blob_oid = {
  39        EMPTY_BLOB_SHA1_BIN_LITERAL
  40};
  41
  42static void git_hash_sha1_init(git_hash_ctx *ctx)
  43{
  44        git_SHA1_Init(&ctx->sha1);
  45}
  46
  47static void git_hash_sha1_update(git_hash_ctx *ctx, const void *data, size_t len)
  48{
  49        git_SHA1_Update(&ctx->sha1, data, len);
  50}
  51
  52static void git_hash_sha1_final(unsigned char *hash, git_hash_ctx *ctx)
  53{
  54        git_SHA1_Final(hash, &ctx->sha1);
  55}
  56
  57static void git_hash_unknown_init(git_hash_ctx *ctx)
  58{
  59        die("trying to init unknown hash");
  60}
  61
  62static void git_hash_unknown_update(git_hash_ctx *ctx, const void *data, size_t len)
  63{
  64        die("trying to update unknown hash");
  65}
  66
  67static void git_hash_unknown_final(unsigned char *hash, git_hash_ctx *ctx)
  68{
  69        die("trying to finalize unknown hash");
  70}
  71
  72const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
  73        {
  74                NULL,
  75                0x00000000,
  76                0,
  77                0,
  78                git_hash_unknown_init,
  79                git_hash_unknown_update,
  80                git_hash_unknown_final,
  81                NULL,
  82                NULL,
  83        },
  84        {
  85                "sha-1",
  86                /* "sha1", big-endian */
  87                0x73686131,
  88                GIT_SHA1_RAWSZ,
  89                GIT_SHA1_HEXSZ,
  90                git_hash_sha1_init,
  91                git_hash_sha1_update,
  92                git_hash_sha1_final,
  93                &empty_tree_oid,
  94                &empty_blob_oid,
  95        },
  96};
  97
  98/*
  99 * This is meant to hold a *small* number of objects that you would
 100 * want read_sha1_file() to be able to return, but yet you do not want
 101 * to write them into the object store (e.g. a browse-only
 102 * application).
 103 */
 104static struct cached_object {
 105        unsigned char sha1[20];
 106        enum object_type type;
 107        void *buf;
 108        unsigned long size;
 109} *cached_objects;
 110static int cached_object_nr, cached_object_alloc;
 111
 112static struct cached_object empty_tree = {
 113        EMPTY_TREE_SHA1_BIN_LITERAL,
 114        OBJ_TREE,
 115        "",
 116        0
 117};
 118
 119static struct cached_object *find_cached_object(const unsigned char *sha1)
 120{
 121        int i;
 122        struct cached_object *co = cached_objects;
 123
 124        for (i = 0; i < cached_object_nr; i++, co++) {
 125                if (!hashcmp(co->sha1, sha1))
 126                        return co;
 127        }
 128        if (!hashcmp(sha1, empty_tree.sha1))
 129                return &empty_tree;
 130        return NULL;
 131}
 132
 133
 134static int get_conv_flags(unsigned flags)
 135{
 136        if (flags & HASH_RENORMALIZE)
 137                return CONV_EOL_RENORMALIZE;
 138        else if (flags & HASH_WRITE_OBJECT)
 139          return global_conv_flags_eol;
 140        else
 141                return 0;
 142}
 143
 144
 145int mkdir_in_gitdir(const char *path)
 146{
 147        if (mkdir(path, 0777)) {
 148                int saved_errno = errno;
 149                struct stat st;
 150                struct strbuf sb = STRBUF_INIT;
 151
 152                if (errno != EEXIST)
 153                        return -1;
 154                /*
 155                 * Are we looking at a path in a symlinked worktree
 156                 * whose original repository does not yet have it?
 157                 * e.g. .git/rr-cache pointing at its original
 158                 * repository in which the user hasn't performed any
 159                 * conflict resolution yet?
 160                 */
 161                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 162                    strbuf_readlink(&sb, path, st.st_size) ||
 163                    !is_absolute_path(sb.buf) ||
 164                    mkdir(sb.buf, 0777)) {
 165                        strbuf_release(&sb);
 166                        errno = saved_errno;
 167                        return -1;
 168                }
 169                strbuf_release(&sb);
 170        }
 171        return adjust_shared_perm(path);
 172}
 173
 174enum scld_error safe_create_leading_directories(char *path)
 175{
 176        char *next_component = path + offset_1st_component(path);
 177        enum scld_error ret = SCLD_OK;
 178
 179        while (ret == SCLD_OK && next_component) {
 180                struct stat st;
 181                char *slash = next_component, slash_character;
 182
 183                while (*slash && !is_dir_sep(*slash))
 184                        slash++;
 185
 186                if (!*slash)
 187                        break;
 188
 189                next_component = slash + 1;
 190                while (is_dir_sep(*next_component))
 191                        next_component++;
 192                if (!*next_component)
 193                        break;
 194
 195                slash_character = *slash;
 196                *slash = '\0';
 197                if (!stat(path, &st)) {
 198                        /* path exists */
 199                        if (!S_ISDIR(st.st_mode)) {
 200                                errno = ENOTDIR;
 201                                ret = SCLD_EXISTS;
 202                        }
 203                } else if (mkdir(path, 0777)) {
 204                        if (errno == EEXIST &&
 205                            !stat(path, &st) && S_ISDIR(st.st_mode))
 206                                ; /* somebody created it since we checked */
 207                        else if (errno == ENOENT)
 208                                /*
 209                                 * Either mkdir() failed because
 210                                 * somebody just pruned the containing
 211                                 * directory, or stat() failed because
 212                                 * the file that was in our way was
 213                                 * just removed.  Either way, inform
 214                                 * the caller that it might be worth
 215                                 * trying again:
 216                                 */
 217                                ret = SCLD_VANISHED;
 218                        else
 219                                ret = SCLD_FAILED;
 220                } else if (adjust_shared_perm(path)) {
 221                        ret = SCLD_PERMS;
 222                }
 223                *slash = slash_character;
 224        }
 225        return ret;
 226}
 227
 228enum scld_error safe_create_leading_directories_const(const char *path)
 229{
 230        int save_errno;
 231        /* path points to cache entries, so xstrdup before messing with it */
 232        char *buf = xstrdup(path);
 233        enum scld_error result = safe_create_leading_directories(buf);
 234
 235        save_errno = errno;
 236        free(buf);
 237        errno = save_errno;
 238        return result;
 239}
 240
 241int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 242{
 243        /*
 244         * The number of times we will try to remove empty directories
 245         * in the way of path. This is only 1 because if another
 246         * process is racily creating directories that conflict with
 247         * us, we don't want to fight against them.
 248         */
 249        int remove_directories_remaining = 1;
 250
 251        /*
 252         * The number of times that we will try to create the
 253         * directories containing path. We are willing to attempt this
 254         * more than once, because another process could be trying to
 255         * clean up empty directories at the same time as we are
 256         * trying to create them.
 257         */
 258        int create_directories_remaining = 3;
 259
 260        /* A scratch copy of path, filled lazily if we need it: */
 261        struct strbuf path_copy = STRBUF_INIT;
 262
 263        int ret, save_errno;
 264
 265        /* Sanity check: */
 266        assert(*path);
 267
 268retry_fn:
 269        ret = fn(path, cb);
 270        save_errno = errno;
 271        if (!ret)
 272                goto out;
 273
 274        if (errno == EISDIR && remove_directories_remaining-- > 0) {
 275                /*
 276                 * A directory is in the way. Maybe it is empty; try
 277                 * to remove it:
 278                 */
 279                if (!path_copy.len)
 280                        strbuf_addstr(&path_copy, path);
 281
 282                if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 283                        goto retry_fn;
 284        } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 285                /*
 286                 * Maybe the containing directory didn't exist, or
 287                 * maybe it was just deleted by a process that is
 288                 * racing with us to clean up empty directories. Try
 289                 * to create it:
 290                 */
 291                enum scld_error scld_result;
 292
 293                if (!path_copy.len)
 294                        strbuf_addstr(&path_copy, path);
 295
 296                do {
 297                        scld_result = safe_create_leading_directories(path_copy.buf);
 298                        if (scld_result == SCLD_OK)
 299                                goto retry_fn;
 300                } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 301        }
 302
 303out:
 304        strbuf_release(&path_copy);
 305        errno = save_errno;
 306        return ret;
 307}
 308
 309static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 310{
 311        int i;
 312        for (i = 0; i < 20; i++) {
 313                static char hex[] = "0123456789abcdef";
 314                unsigned int val = sha1[i];
 315                strbuf_addch(buf, hex[val >> 4]);
 316                strbuf_addch(buf, hex[val & 0xf]);
 317                if (!i)
 318                        strbuf_addch(buf, '/');
 319        }
 320}
 321
 322void sha1_file_name(struct strbuf *buf, const unsigned char *sha1)
 323{
 324        strbuf_addstr(buf, get_object_directory());
 325        strbuf_addch(buf, '/');
 326        fill_sha1_path(buf, sha1);
 327}
 328
 329struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 330{
 331        strbuf_setlen(&alt->scratch, alt->base_len);
 332        return &alt->scratch;
 333}
 334
 335static const char *alt_sha1_path(struct alternate_object_database *alt,
 336                                 const unsigned char *sha1)
 337{
 338        struct strbuf *buf = alt_scratch_buf(alt);
 339        fill_sha1_path(buf, sha1);
 340        return buf->buf;
 341}
 342
 343struct alternate_object_database *alt_odb_list;
 344static struct alternate_object_database **alt_odb_tail;
 345
 346/*
 347 * Return non-zero iff the path is usable as an alternate object database.
 348 */
 349static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 350{
 351        struct alternate_object_database *alt;
 352
 353        /* Detect cases where alternate disappeared */
 354        if (!is_directory(path->buf)) {
 355                error("object directory %s does not exist; "
 356                      "check .git/objects/info/alternates.",
 357                      path->buf);
 358                return 0;
 359        }
 360
 361        /*
 362         * Prevent the common mistake of listing the same
 363         * thing twice, or object directory itself.
 364         */
 365        for (alt = alt_odb_list; alt; alt = alt->next) {
 366                if (!fspathcmp(path->buf, alt->path))
 367                        return 0;
 368        }
 369        if (!fspathcmp(path->buf, normalized_objdir))
 370                return 0;
 371
 372        return 1;
 373}
 374
 375/*
 376 * Prepare alternate object database registry.
 377 *
 378 * The variable alt_odb_list points at the list of struct
 379 * alternate_object_database.  The elements on this list come from
 380 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 381 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 382 * whose contents is similar to that environment variable but can be
 383 * LF separated.  Its base points at a statically allocated buffer that
 384 * contains "/the/directory/corresponding/to/.git/objects/...", while
 385 * its name points just after the slash at the end of ".git/objects/"
 386 * in the example above, and has enough space to hold 40-byte hex
 387 * SHA1, an extra slash for the first level indirection, and the
 388 * terminating NUL.
 389 */
 390static void read_info_alternates(const char * relative_base, int depth);
 391static int link_alt_odb_entry(const char *entry, const char *relative_base,
 392        int depth, const char *normalized_objdir)
 393{
 394        struct alternate_object_database *ent;
 395        struct strbuf pathbuf = STRBUF_INIT;
 396
 397        if (!is_absolute_path(entry) && relative_base) {
 398                strbuf_realpath(&pathbuf, relative_base, 1);
 399                strbuf_addch(&pathbuf, '/');
 400        }
 401        strbuf_addstr(&pathbuf, entry);
 402
 403        if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 404                error("unable to normalize alternate object path: %s",
 405                      pathbuf.buf);
 406                strbuf_release(&pathbuf);
 407                return -1;
 408        }
 409
 410        /*
 411         * The trailing slash after the directory name is given by
 412         * this function at the end. Remove duplicates.
 413         */
 414        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 415                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 416
 417        if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 418                strbuf_release(&pathbuf);
 419                return -1;
 420        }
 421
 422        ent = alloc_alt_odb(pathbuf.buf);
 423
 424        /* add the alternate entry */
 425        *alt_odb_tail = ent;
 426        alt_odb_tail = &(ent->next);
 427        ent->next = NULL;
 428
 429        /* recursively add alternates */
 430        read_info_alternates(pathbuf.buf, depth + 1);
 431
 432        strbuf_release(&pathbuf);
 433        return 0;
 434}
 435
 436static const char *parse_alt_odb_entry(const char *string,
 437                                       int sep,
 438                                       struct strbuf *out)
 439{
 440        const char *end;
 441
 442        strbuf_reset(out);
 443
 444        if (*string == '#') {
 445                /* comment; consume up to next separator */
 446                end = strchrnul(string, sep);
 447        } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 448                /*
 449                 * quoted path; unquote_c_style has copied the
 450                 * data for us and set "end". Broken quoting (e.g.,
 451                 * an entry that doesn't end with a quote) falls
 452                 * back to the unquoted case below.
 453                 */
 454        } else {
 455                /* normal, unquoted path */
 456                end = strchrnul(string, sep);
 457                strbuf_add(out, string, end - string);
 458        }
 459
 460        if (*end)
 461                end++;
 462        return end;
 463}
 464
 465static void link_alt_odb_entries(const char *alt, int sep,
 466                                 const char *relative_base, int depth)
 467{
 468        struct strbuf objdirbuf = STRBUF_INIT;
 469        struct strbuf entry = STRBUF_INIT;
 470
 471        if (!alt || !*alt)
 472                return;
 473
 474        if (depth > 5) {
 475                error("%s: ignoring alternate object stores, nesting too deep.",
 476                                relative_base);
 477                return;
 478        }
 479
 480        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 481        if (strbuf_normalize_path(&objdirbuf) < 0)
 482                die("unable to normalize object directory: %s",
 483                    objdirbuf.buf);
 484
 485        while (*alt) {
 486                alt = parse_alt_odb_entry(alt, sep, &entry);
 487                if (!entry.len)
 488                        continue;
 489                link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 490        }
 491        strbuf_release(&entry);
 492        strbuf_release(&objdirbuf);
 493}
 494
 495static void read_info_alternates(const char * relative_base, int depth)
 496{
 497        char *path;
 498        struct strbuf buf = STRBUF_INIT;
 499
 500        path = xstrfmt("%s/info/alternates", relative_base);
 501        if (strbuf_read_file(&buf, path, 1024) < 0) {
 502                warn_on_fopen_errors(path);
 503                free(path);
 504                return;
 505        }
 506
 507        link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 508        strbuf_release(&buf);
 509        free(path);
 510}
 511
 512struct alternate_object_database *alloc_alt_odb(const char *dir)
 513{
 514        struct alternate_object_database *ent;
 515
 516        FLEX_ALLOC_STR(ent, path, dir);
 517        strbuf_init(&ent->scratch, 0);
 518        strbuf_addf(&ent->scratch, "%s/", dir);
 519        ent->base_len = ent->scratch.len;
 520
 521        return ent;
 522}
 523
 524void add_to_alternates_file(const char *reference)
 525{
 526        struct lock_file lock = LOCK_INIT;
 527        char *alts = git_pathdup("objects/info/alternates");
 528        FILE *in, *out;
 529        int found = 0;
 530
 531        hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 532        out = fdopen_lock_file(&lock, "w");
 533        if (!out)
 534                die_errno("unable to fdopen alternates lockfile");
 535
 536        in = fopen(alts, "r");
 537        if (in) {
 538                struct strbuf line = STRBUF_INIT;
 539
 540                while (strbuf_getline(&line, in) != EOF) {
 541                        if (!strcmp(reference, line.buf)) {
 542                                found = 1;
 543                                break;
 544                        }
 545                        fprintf_or_die(out, "%s\n", line.buf);
 546                }
 547
 548                strbuf_release(&line);
 549                fclose(in);
 550        }
 551        else if (errno != ENOENT)
 552                die_errno("unable to read alternates file");
 553
 554        if (found) {
 555                rollback_lock_file(&lock);
 556        } else {
 557                fprintf_or_die(out, "%s\n", reference);
 558                if (commit_lock_file(&lock))
 559                        die_errno("unable to move new alternates file into place");
 560                if (alt_odb_tail)
 561                        link_alt_odb_entries(reference, '\n', NULL, 0);
 562        }
 563        free(alts);
 564}
 565
 566void add_to_alternates_memory(const char *reference)
 567{
 568        /*
 569         * Make sure alternates are initialized, or else our entry may be
 570         * overwritten when they are.
 571         */
 572        prepare_alt_odb();
 573
 574        link_alt_odb_entries(reference, '\n', NULL, 0);
 575}
 576
 577/*
 578 * Compute the exact path an alternate is at and returns it. In case of
 579 * error NULL is returned and the human readable error is added to `err`
 580 * `path` may be relative and should point to $GITDIR.
 581 * `err` must not be null.
 582 */
 583char *compute_alternate_path(const char *path, struct strbuf *err)
 584{
 585        char *ref_git = NULL;
 586        const char *repo, *ref_git_s;
 587        int seen_error = 0;
 588
 589        ref_git_s = real_path_if_valid(path);
 590        if (!ref_git_s) {
 591                seen_error = 1;
 592                strbuf_addf(err, _("path '%s' does not exist"), path);
 593                goto out;
 594        } else
 595                /*
 596                 * Beware: read_gitfile(), real_path() and mkpath()
 597                 * return static buffer
 598                 */
 599                ref_git = xstrdup(ref_git_s);
 600
 601        repo = read_gitfile(ref_git);
 602        if (!repo)
 603                repo = read_gitfile(mkpath("%s/.git", ref_git));
 604        if (repo) {
 605                free(ref_git);
 606                ref_git = xstrdup(repo);
 607        }
 608
 609        if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 610                char *ref_git_git = mkpathdup("%s/.git", ref_git);
 611                free(ref_git);
 612                ref_git = ref_git_git;
 613        } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 614                struct strbuf sb = STRBUF_INIT;
 615                seen_error = 1;
 616                if (get_common_dir(&sb, ref_git)) {
 617                        strbuf_addf(err,
 618                                    _("reference repository '%s' as a linked "
 619                                      "checkout is not supported yet."),
 620                                    path);
 621                        goto out;
 622                }
 623
 624                strbuf_addf(err, _("reference repository '%s' is not a "
 625                                        "local repository."), path);
 626                goto out;
 627        }
 628
 629        if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 630                strbuf_addf(err, _("reference repository '%s' is shallow"),
 631                            path);
 632                seen_error = 1;
 633                goto out;
 634        }
 635
 636        if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 637                strbuf_addf(err,
 638                            _("reference repository '%s' is grafted"),
 639                            path);
 640                seen_error = 1;
 641                goto out;
 642        }
 643
 644out:
 645        if (seen_error) {
 646                FREE_AND_NULL(ref_git);
 647        }
 648
 649        return ref_git;
 650}
 651
 652int foreach_alt_odb(alt_odb_fn fn, void *cb)
 653{
 654        struct alternate_object_database *ent;
 655        int r = 0;
 656
 657        prepare_alt_odb();
 658        for (ent = alt_odb_list; ent; ent = ent->next) {
 659                r = fn(ent, cb);
 660                if (r)
 661                        break;
 662        }
 663        return r;
 664}
 665
 666void prepare_alt_odb(void)
 667{
 668        const char *alt;
 669
 670        if (alt_odb_tail)
 671                return;
 672
 673        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 674
 675        alt_odb_tail = &alt_odb_list;
 676        link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
 677
 678        read_info_alternates(get_object_directory(), 0);
 679}
 680
 681/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 682static int freshen_file(const char *fn)
 683{
 684        struct utimbuf t;
 685        t.actime = t.modtime = time(NULL);
 686        return !utime(fn, &t);
 687}
 688
 689/*
 690 * All of the check_and_freshen functions return 1 if the file exists and was
 691 * freshened (if freshening was requested), 0 otherwise. If they return
 692 * 0, you should not assume that it is safe to skip a write of the object (it
 693 * either does not exist on disk, or has a stale mtime and may be subject to
 694 * pruning).
 695 */
 696int check_and_freshen_file(const char *fn, int freshen)
 697{
 698        if (access(fn, F_OK))
 699                return 0;
 700        if (freshen && !freshen_file(fn))
 701                return 0;
 702        return 1;
 703}
 704
 705static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 706{
 707        static struct strbuf buf = STRBUF_INIT;
 708
 709        strbuf_reset(&buf);
 710        sha1_file_name(&buf, sha1);
 711
 712        return check_and_freshen_file(buf.buf, freshen);
 713}
 714
 715static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 716{
 717        struct alternate_object_database *alt;
 718        prepare_alt_odb();
 719        for (alt = alt_odb_list; alt; alt = alt->next) {
 720                const char *path = alt_sha1_path(alt, sha1);
 721                if (check_and_freshen_file(path, freshen))
 722                        return 1;
 723        }
 724        return 0;
 725}
 726
 727static int check_and_freshen(const unsigned char *sha1, int freshen)
 728{
 729        return check_and_freshen_local(sha1, freshen) ||
 730               check_and_freshen_nonlocal(sha1, freshen);
 731}
 732
 733int has_loose_object_nonlocal(const unsigned char *sha1)
 734{
 735        return check_and_freshen_nonlocal(sha1, 0);
 736}
 737
 738static int has_loose_object(const unsigned char *sha1)
 739{
 740        return check_and_freshen(sha1, 0);
 741}
 742
 743static void mmap_limit_check(size_t length)
 744{
 745        static size_t limit = 0;
 746        if (!limit) {
 747                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 748                if (!limit)
 749                        limit = SIZE_MAX;
 750        }
 751        if (length > limit)
 752                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 753                    (uintmax_t)length, (uintmax_t)limit);
 754}
 755
 756void *xmmap_gently(void *start, size_t length,
 757                  int prot, int flags, int fd, off_t offset)
 758{
 759        void *ret;
 760
 761        mmap_limit_check(length);
 762        ret = mmap(start, length, prot, flags, fd, offset);
 763        if (ret == MAP_FAILED) {
 764                if (!length)
 765                        return NULL;
 766                release_pack_memory(length);
 767                ret = mmap(start, length, prot, flags, fd, offset);
 768        }
 769        return ret;
 770}
 771
 772void *xmmap(void *start, size_t length,
 773        int prot, int flags, int fd, off_t offset)
 774{
 775        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 776        if (ret == MAP_FAILED)
 777                die_errno("mmap failed");
 778        return ret;
 779}
 780
 781/*
 782 * With an in-core object data in "map", rehash it to make sure the
 783 * object name actually matches "sha1" to detect object corruption.
 784 * With "map" == NULL, try reading the object named with "sha1" using
 785 * the streaming interface and rehash it to do the same.
 786 */
 787int check_sha1_signature(const unsigned char *sha1, void *map,
 788                         unsigned long size, const char *type)
 789{
 790        struct object_id real_oid;
 791        enum object_type obj_type;
 792        struct git_istream *st;
 793        git_hash_ctx c;
 794        char hdr[32];
 795        int hdrlen;
 796
 797        if (map) {
 798                hash_object_file(map, size, type, &real_oid);
 799                return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 800        }
 801
 802        st = open_istream(sha1, &obj_type, &size, NULL);
 803        if (!st)
 804                return -1;
 805
 806        /* Generate the header */
 807        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", type_name(obj_type), size) + 1;
 808
 809        /* Sha1.. */
 810        the_hash_algo->init_fn(&c);
 811        the_hash_algo->update_fn(&c, hdr, hdrlen);
 812        for (;;) {
 813                char buf[1024 * 16];
 814                ssize_t readlen = read_istream(st, buf, sizeof(buf));
 815
 816                if (readlen < 0) {
 817                        close_istream(st);
 818                        return -1;
 819                }
 820                if (!readlen)
 821                        break;
 822                the_hash_algo->update_fn(&c, buf, readlen);
 823        }
 824        the_hash_algo->final_fn(real_oid.hash, &c);
 825        close_istream(st);
 826        return hashcmp(sha1, real_oid.hash) ? -1 : 0;
 827}
 828
 829int git_open_cloexec(const char *name, int flags)
 830{
 831        int fd;
 832        static int o_cloexec = O_CLOEXEC;
 833
 834        fd = open(name, flags | o_cloexec);
 835        if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 836                /* Try again w/o O_CLOEXEC: the kernel might not support it */
 837                o_cloexec &= ~O_CLOEXEC;
 838                fd = open(name, flags | o_cloexec);
 839        }
 840
 841#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 842        {
 843                static int fd_cloexec = FD_CLOEXEC;
 844
 845                if (!o_cloexec && 0 <= fd && fd_cloexec) {
 846                        /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 847                        int flags = fcntl(fd, F_GETFD);
 848                        if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 849                                fd_cloexec = 0;
 850                }
 851        }
 852#endif
 853        return fd;
 854}
 855
 856/*
 857 * Find "sha1" as a loose object in the local repository or in an alternate.
 858 * Returns 0 on success, negative on failure.
 859 *
 860 * The "path" out-parameter will give the path of the object we found (if any).
 861 * Note that it may point to static storage and is only valid until another
 862 * call to sha1_file_name(), etc.
 863 */
 864static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 865                          const char **path)
 866{
 867        struct alternate_object_database *alt;
 868        static struct strbuf buf = STRBUF_INIT;
 869
 870        strbuf_reset(&buf);
 871        sha1_file_name(&buf, sha1);
 872        *path = buf.buf;
 873
 874        if (!lstat(*path, st))
 875                return 0;
 876
 877        prepare_alt_odb();
 878        errno = ENOENT;
 879        for (alt = alt_odb_list; alt; alt = alt->next) {
 880                *path = alt_sha1_path(alt, sha1);
 881                if (!lstat(*path, st))
 882                        return 0;
 883        }
 884
 885        return -1;
 886}
 887
 888/*
 889 * Like stat_sha1_file(), but actually open the object and return the
 890 * descriptor. See the caveats on the "path" parameter above.
 891 */
 892static int open_sha1_file(const unsigned char *sha1, const char **path)
 893{
 894        int fd;
 895        struct alternate_object_database *alt;
 896        int most_interesting_errno;
 897        static struct strbuf buf = STRBUF_INIT;
 898
 899        strbuf_reset(&buf);
 900        sha1_file_name(&buf, sha1);
 901        *path = buf.buf;
 902
 903        fd = git_open(*path);
 904        if (fd >= 0)
 905                return fd;
 906        most_interesting_errno = errno;
 907
 908        prepare_alt_odb();
 909        for (alt = alt_odb_list; alt; alt = alt->next) {
 910                *path = alt_sha1_path(alt, sha1);
 911                fd = git_open(*path);
 912                if (fd >= 0)
 913                        return fd;
 914                if (most_interesting_errno == ENOENT)
 915                        most_interesting_errno = errno;
 916        }
 917        errno = most_interesting_errno;
 918        return -1;
 919}
 920
 921/*
 922 * Map the loose object at "path" if it is not NULL, or the path found by
 923 * searching for a loose object named "sha1".
 924 */
 925static void *map_sha1_file_1(const char *path,
 926                             const unsigned char *sha1,
 927                             unsigned long *size)
 928{
 929        void *map;
 930        int fd;
 931
 932        if (path)
 933                fd = git_open(path);
 934        else
 935                fd = open_sha1_file(sha1, &path);
 936        map = NULL;
 937        if (fd >= 0) {
 938                struct stat st;
 939
 940                if (!fstat(fd, &st)) {
 941                        *size = xsize_t(st.st_size);
 942                        if (!*size) {
 943                                /* mmap() is forbidden on empty files */
 944                                error("object file %s is empty", path);
 945                                return NULL;
 946                        }
 947                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 948                }
 949                close(fd);
 950        }
 951        return map;
 952}
 953
 954void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 955{
 956        return map_sha1_file_1(NULL, sha1, size);
 957}
 958
 959static int unpack_sha1_short_header(git_zstream *stream,
 960                                    unsigned char *map, unsigned long mapsize,
 961                                    void *buffer, unsigned long bufsiz)
 962{
 963        /* Get the data stream */
 964        memset(stream, 0, sizeof(*stream));
 965        stream->next_in = map;
 966        stream->avail_in = mapsize;
 967        stream->next_out = buffer;
 968        stream->avail_out = bufsiz;
 969
 970        git_inflate_init(stream);
 971        return git_inflate(stream, 0);
 972}
 973
 974int unpack_sha1_header(git_zstream *stream,
 975                       unsigned char *map, unsigned long mapsize,
 976                       void *buffer, unsigned long bufsiz)
 977{
 978        int status = unpack_sha1_short_header(stream, map, mapsize,
 979                                              buffer, bufsiz);
 980
 981        if (status < Z_OK)
 982                return status;
 983
 984        /* Make sure we have the terminating NUL */
 985        if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 986                return -1;
 987        return 0;
 988}
 989
 990static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 991                                        unsigned long mapsize, void *buffer,
 992                                        unsigned long bufsiz, struct strbuf *header)
 993{
 994        int status;
 995
 996        status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 997        if (status < Z_OK)
 998                return -1;
 999
1000        /*
1001         * Check if entire header is unpacked in the first iteration.
1002         */
1003        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1004                return 0;
1005
1006        /*
1007         * buffer[0..bufsiz] was not large enough.  Copy the partial
1008         * result out to header, and then append the result of further
1009         * reading the stream.
1010         */
1011        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1012        stream->next_out = buffer;
1013        stream->avail_out = bufsiz;
1014
1015        do {
1016                status = git_inflate(stream, 0);
1017                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1018                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1019                        return 0;
1020                stream->next_out = buffer;
1021                stream->avail_out = bufsiz;
1022        } while (status != Z_STREAM_END);
1023        return -1;
1024}
1025
1026static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1027{
1028        int bytes = strlen(buffer) + 1;
1029        unsigned char *buf = xmallocz(size);
1030        unsigned long n;
1031        int status = Z_OK;
1032
1033        n = stream->total_out - bytes;
1034        if (n > size)
1035                n = size;
1036        memcpy(buf, (char *) buffer + bytes, n);
1037        bytes = n;
1038        if (bytes <= size) {
1039                /*
1040                 * The above condition must be (bytes <= size), not
1041                 * (bytes < size).  In other words, even though we
1042                 * expect no more output and set avail_out to zero,
1043                 * the input zlib stream may have bytes that express
1044                 * "this concludes the stream", and we *do* want to
1045                 * eat that input.
1046                 *
1047                 * Otherwise we would not be able to test that we
1048                 * consumed all the input to reach the expected size;
1049                 * we also want to check that zlib tells us that all
1050                 * went well with status == Z_STREAM_END at the end.
1051                 */
1052                stream->next_out = buf + bytes;
1053                stream->avail_out = size - bytes;
1054                while (status == Z_OK)
1055                        status = git_inflate(stream, Z_FINISH);
1056        }
1057        if (status == Z_STREAM_END && !stream->avail_in) {
1058                git_inflate_end(stream);
1059                return buf;
1060        }
1061
1062        if (status < 0)
1063                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1064        else if (stream->avail_in)
1065                error("garbage at end of loose object '%s'",
1066                      sha1_to_hex(sha1));
1067        free(buf);
1068        return NULL;
1069}
1070
1071/*
1072 * We used to just use "sscanf()", but that's actually way
1073 * too permissive for what we want to check. So do an anal
1074 * object header parse by hand.
1075 */
1076static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1077                               unsigned int flags)
1078{
1079        const char *type_buf = hdr;
1080        unsigned long size;
1081        int type, type_len = 0;
1082
1083        /*
1084         * The type can be of any size but is followed by
1085         * a space.
1086         */
1087        for (;;) {
1088                char c = *hdr++;
1089                if (!c)
1090                        return -1;
1091                if (c == ' ')
1092                        break;
1093                type_len++;
1094        }
1095
1096        type = type_from_string_gently(type_buf, type_len, 1);
1097        if (oi->type_name)
1098                strbuf_add(oi->type_name, type_buf, type_len);
1099        /*
1100         * Set type to 0 if its an unknown object and
1101         * we're obtaining the type using '--allow-unknown-type'
1102         * option.
1103         */
1104        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1105                type = 0;
1106        else if (type < 0)
1107                die("invalid object type");
1108        if (oi->typep)
1109                *oi->typep = type;
1110
1111        /*
1112         * The length must follow immediately, and be in canonical
1113         * decimal format (ie "010" is not valid).
1114         */
1115        size = *hdr++ - '0';
1116        if (size > 9)
1117                return -1;
1118        if (size) {
1119                for (;;) {
1120                        unsigned long c = *hdr - '0';
1121                        if (c > 9)
1122                                break;
1123                        hdr++;
1124                        size = size * 10 + c;
1125                }
1126        }
1127
1128        if (oi->sizep)
1129                *oi->sizep = size;
1130
1131        /*
1132         * The length must be followed by a zero byte
1133         */
1134        return *hdr ? -1 : type;
1135}
1136
1137int parse_sha1_header(const char *hdr, unsigned long *sizep)
1138{
1139        struct object_info oi = OBJECT_INFO_INIT;
1140
1141        oi.sizep = sizep;
1142        return parse_sha1_header_extended(hdr, &oi, 0);
1143}
1144
1145static int sha1_loose_object_info(const unsigned char *sha1,
1146                                  struct object_info *oi,
1147                                  int flags)
1148{
1149        int status = 0;
1150        unsigned long mapsize;
1151        void *map;
1152        git_zstream stream;
1153        char hdr[32];
1154        struct strbuf hdrbuf = STRBUF_INIT;
1155        unsigned long size_scratch;
1156
1157        if (oi->delta_base_sha1)
1158                hashclr(oi->delta_base_sha1);
1159
1160        /*
1161         * If we don't care about type or size, then we don't
1162         * need to look inside the object at all. Note that we
1163         * do not optimize out the stat call, even if the
1164         * caller doesn't care about the disk-size, since our
1165         * return value implicitly indicates whether the
1166         * object even exists.
1167         */
1168        if (!oi->typep && !oi->type_name && !oi->sizep && !oi->contentp) {
1169                const char *path;
1170                struct stat st;
1171                if (stat_sha1_file(sha1, &st, &path) < 0)
1172                        return -1;
1173                if (oi->disk_sizep)
1174                        *oi->disk_sizep = st.st_size;
1175                return 0;
1176        }
1177
1178        map = map_sha1_file(sha1, &mapsize);
1179        if (!map)
1180                return -1;
1181
1182        if (!oi->sizep)
1183                oi->sizep = &size_scratch;
1184
1185        if (oi->disk_sizep)
1186                *oi->disk_sizep = mapsize;
1187        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1188                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1189                        status = error("unable to unpack %s header with --allow-unknown-type",
1190                                       sha1_to_hex(sha1));
1191        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1192                status = error("unable to unpack %s header",
1193                               sha1_to_hex(sha1));
1194        if (status < 0)
1195                ; /* Do nothing */
1196        else if (hdrbuf.len) {
1197                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1198                        status = error("unable to parse %s header with --allow-unknown-type",
1199                                       sha1_to_hex(sha1));
1200        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1201                status = error("unable to parse %s header", sha1_to_hex(sha1));
1202
1203        if (status >= 0 && oi->contentp) {
1204                *oi->contentp = unpack_sha1_rest(&stream, hdr,
1205                                                 *oi->sizep, sha1);
1206                if (!*oi->contentp) {
1207                        git_inflate_end(&stream);
1208                        status = -1;
1209                }
1210        } else
1211                git_inflate_end(&stream);
1212
1213        munmap(map, mapsize);
1214        if (status && oi->typep)
1215                *oi->typep = status;
1216        if (oi->sizep == &size_scratch)
1217                oi->sizep = NULL;
1218        strbuf_release(&hdrbuf);
1219        oi->whence = OI_LOOSE;
1220        return (status < 0) ? status : 0;
1221}
1222
1223int fetch_if_missing = 1;
1224
1225int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1226{
1227        static struct object_info blank_oi = OBJECT_INFO_INIT;
1228        struct pack_entry e;
1229        int rtype;
1230        const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1231                                    lookup_replace_object(sha1) :
1232                                    sha1;
1233        int already_retried = 0;
1234
1235        if (is_null_sha1(real))
1236                return -1;
1237
1238        if (!oi)
1239                oi = &blank_oi;
1240
1241        if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1242                struct cached_object *co = find_cached_object(real);
1243                if (co) {
1244                        if (oi->typep)
1245                                *(oi->typep) = co->type;
1246                        if (oi->sizep)
1247                                *(oi->sizep) = co->size;
1248                        if (oi->disk_sizep)
1249                                *(oi->disk_sizep) = 0;
1250                        if (oi->delta_base_sha1)
1251                                hashclr(oi->delta_base_sha1);
1252                        if (oi->type_name)
1253                                strbuf_addstr(oi->type_name, type_name(co->type));
1254                        if (oi->contentp)
1255                                *oi->contentp = xmemdupz(co->buf, co->size);
1256                        oi->whence = OI_CACHED;
1257                        return 0;
1258                }
1259        }
1260
1261        while (1) {
1262                if (find_pack_entry(real, &e))
1263                        break;
1264
1265                /* Most likely it's a loose object. */
1266                if (!sha1_loose_object_info(real, oi, flags))
1267                        return 0;
1268
1269                /* Not a loose object; someone else may have just packed it. */
1270                reprepare_packed_git();
1271                if (find_pack_entry(real, &e))
1272                        break;
1273
1274                /* Check if it is a missing object */
1275                if (fetch_if_missing && repository_format_partial_clone &&
1276                    !already_retried) {
1277                        /*
1278                         * TODO Investigate haveing fetch_object() return
1279                         * TODO error/success and stopping the music here.
1280                         */
1281                        fetch_object(repository_format_partial_clone, real);
1282                        already_retried = 1;
1283                        continue;
1284                }
1285
1286                return -1;
1287        }
1288
1289        if (oi == &blank_oi)
1290                /*
1291                 * We know that the caller doesn't actually need the
1292                 * information below, so return early.
1293                 */
1294                return 0;
1295        rtype = packed_object_info(e.p, e.offset, oi);
1296        if (rtype < 0) {
1297                mark_bad_packed_object(e.p, real);
1298                return sha1_object_info_extended(real, oi, 0);
1299        } else if (oi->whence == OI_PACKED) {
1300                oi->u.packed.offset = e.offset;
1301                oi->u.packed.pack = e.p;
1302                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1303                                         rtype == OBJ_OFS_DELTA);
1304        }
1305
1306        return 0;
1307}
1308
1309/* returns enum object_type or negative */
1310int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1311{
1312        enum object_type type;
1313        struct object_info oi = OBJECT_INFO_INIT;
1314
1315        oi.typep = &type;
1316        oi.sizep = sizep;
1317        if (sha1_object_info_extended(sha1, &oi,
1318                                      OBJECT_INFO_LOOKUP_REPLACE) < 0)
1319                return -1;
1320        return type;
1321}
1322
1323static void *read_object(const unsigned char *sha1, enum object_type *type,
1324                         unsigned long *size)
1325{
1326        struct object_info oi = OBJECT_INFO_INIT;
1327        void *content;
1328        oi.typep = type;
1329        oi.sizep = size;
1330        oi.contentp = &content;
1331
1332        if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1333                return NULL;
1334        return content;
1335}
1336
1337int pretend_object_file(void *buf, unsigned long len, enum object_type type,
1338                        struct object_id *oid)
1339{
1340        struct cached_object *co;
1341
1342        hash_object_file(buf, len, type_name(type), oid);
1343        if (has_sha1_file(oid->hash) || find_cached_object(oid->hash))
1344                return 0;
1345        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1346        co = &cached_objects[cached_object_nr++];
1347        co->size = len;
1348        co->type = type;
1349        co->buf = xmalloc(len);
1350        memcpy(co->buf, buf, len);
1351        hashcpy(co->sha1, oid->hash);
1352        return 0;
1353}
1354
1355/*
1356 * This function dies on corrupt objects; the callers who want to
1357 * deal with them should arrange to call read_object() and give error
1358 * messages themselves.
1359 */
1360void *read_sha1_file_extended(const unsigned char *sha1,
1361                              enum object_type *type,
1362                              unsigned long *size,
1363                              int lookup_replace)
1364{
1365        void *data;
1366        const struct packed_git *p;
1367        const char *path;
1368        struct stat st;
1369        const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1370                                                   : sha1;
1371
1372        errno = 0;
1373        data = read_object(repl, type, size);
1374        if (data)
1375                return data;
1376
1377        if (errno && errno != ENOENT)
1378                die_errno("failed to read object %s", sha1_to_hex(sha1));
1379
1380        /* die if we replaced an object with one that does not exist */
1381        if (repl != sha1)
1382                die("replacement %s not found for %s",
1383                    sha1_to_hex(repl), sha1_to_hex(sha1));
1384
1385        if (!stat_sha1_file(repl, &st, &path))
1386                die("loose object %s (stored in %s) is corrupt",
1387                    sha1_to_hex(repl), path);
1388
1389        if ((p = has_packed_and_bad(repl)) != NULL)
1390                die("packed object %s (stored in %s) is corrupt",
1391                    sha1_to_hex(repl), p->pack_name);
1392
1393        return NULL;
1394}
1395
1396void *read_object_with_reference(const unsigned char *sha1,
1397                                 const char *required_type_name,
1398                                 unsigned long *size,
1399                                 unsigned char *actual_sha1_return)
1400{
1401        enum object_type type, required_type;
1402        void *buffer;
1403        unsigned long isize;
1404        unsigned char actual_sha1[20];
1405
1406        required_type = type_from_string(required_type_name);
1407        hashcpy(actual_sha1, sha1);
1408        while (1) {
1409                int ref_length = -1;
1410                const char *ref_type = NULL;
1411
1412                buffer = read_sha1_file(actual_sha1, &type, &isize);
1413                if (!buffer)
1414                        return NULL;
1415                if (type == required_type) {
1416                        *size = isize;
1417                        if (actual_sha1_return)
1418                                hashcpy(actual_sha1_return, actual_sha1);
1419                        return buffer;
1420                }
1421                /* Handle references */
1422                else if (type == OBJ_COMMIT)
1423                        ref_type = "tree ";
1424                else if (type == OBJ_TAG)
1425                        ref_type = "object ";
1426                else {
1427                        free(buffer);
1428                        return NULL;
1429                }
1430                ref_length = strlen(ref_type);
1431
1432                if (ref_length + 40 > isize ||
1433                    memcmp(buffer, ref_type, ref_length) ||
1434                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1435                        free(buffer);
1436                        return NULL;
1437                }
1438                free(buffer);
1439                /* Now we have the ID of the referred-to object in
1440                 * actual_sha1.  Check again. */
1441        }
1442}
1443
1444static void write_object_file_prepare(const void *buf, unsigned long len,
1445                                      const char *type, struct object_id *oid,
1446                                      char *hdr, int *hdrlen)
1447{
1448        git_hash_ctx c;
1449
1450        /* Generate the header */
1451        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1452
1453        /* Sha1.. */
1454        the_hash_algo->init_fn(&c);
1455        the_hash_algo->update_fn(&c, hdr, *hdrlen);
1456        the_hash_algo->update_fn(&c, buf, len);
1457        the_hash_algo->final_fn(oid->hash, &c);
1458}
1459
1460/*
1461 * Move the just written object into its final resting place.
1462 */
1463int finalize_object_file(const char *tmpfile, const char *filename)
1464{
1465        int ret = 0;
1466
1467        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1468                goto try_rename;
1469        else if (link(tmpfile, filename))
1470                ret = errno;
1471
1472        /*
1473         * Coda hack - coda doesn't like cross-directory links,
1474         * so we fall back to a rename, which will mean that it
1475         * won't be able to check collisions, but that's not a
1476         * big deal.
1477         *
1478         * The same holds for FAT formatted media.
1479         *
1480         * When this succeeds, we just return.  We have nothing
1481         * left to unlink.
1482         */
1483        if (ret && ret != EEXIST) {
1484        try_rename:
1485                if (!rename(tmpfile, filename))
1486                        goto out;
1487                ret = errno;
1488        }
1489        unlink_or_warn(tmpfile);
1490        if (ret) {
1491                if (ret != EEXIST) {
1492                        return error_errno("unable to write sha1 filename %s", filename);
1493                }
1494                /* FIXME!!! Collision check here ? */
1495        }
1496
1497out:
1498        if (adjust_shared_perm(filename))
1499                return error("unable to set permission to '%s'", filename);
1500        return 0;
1501}
1502
1503static int write_buffer(int fd, const void *buf, size_t len)
1504{
1505        if (write_in_full(fd, buf, len) < 0)
1506                return error_errno("file write error");
1507        return 0;
1508}
1509
1510int hash_object_file(const void *buf, unsigned long len, const char *type,
1511                     struct object_id *oid)
1512{
1513        char hdr[32];
1514        int hdrlen = sizeof(hdr);
1515        write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1516        return 0;
1517}
1518
1519/* Finalize a file on disk, and close it. */
1520static void close_sha1_file(int fd)
1521{
1522        if (fsync_object_files)
1523                fsync_or_die(fd, "sha1 file");
1524        if (close(fd) != 0)
1525                die_errno("error when closing sha1 file");
1526}
1527
1528/* Size of directory component, including the ending '/' */
1529static inline int directory_size(const char *filename)
1530{
1531        const char *s = strrchr(filename, '/');
1532        if (!s)
1533                return 0;
1534        return s - filename + 1;
1535}
1536
1537/*
1538 * This creates a temporary file in the same directory as the final
1539 * 'filename'
1540 *
1541 * We want to avoid cross-directory filename renames, because those
1542 * can have problems on various filesystems (FAT, NFS, Coda).
1543 */
1544static int create_tmpfile(struct strbuf *tmp, const char *filename)
1545{
1546        int fd, dirlen = directory_size(filename);
1547
1548        strbuf_reset(tmp);
1549        strbuf_add(tmp, filename, dirlen);
1550        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1551        fd = git_mkstemp_mode(tmp->buf, 0444);
1552        if (fd < 0 && dirlen && errno == ENOENT) {
1553                /*
1554                 * Make sure the directory exists; note that the contents
1555                 * of the buffer are undefined after mkstemp returns an
1556                 * error, so we have to rewrite the whole buffer from
1557                 * scratch.
1558                 */
1559                strbuf_reset(tmp);
1560                strbuf_add(tmp, filename, dirlen - 1);
1561                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1562                        return -1;
1563                if (adjust_shared_perm(tmp->buf))
1564                        return -1;
1565
1566                /* Try again */
1567                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1568                fd = git_mkstemp_mode(tmp->buf, 0444);
1569        }
1570        return fd;
1571}
1572
1573static int write_loose_object(const struct object_id *oid, char *hdr,
1574                              int hdrlen, const void *buf, unsigned long len,
1575                              time_t mtime)
1576{
1577        int fd, ret;
1578        unsigned char compressed[4096];
1579        git_zstream stream;
1580        git_hash_ctx c;
1581        struct object_id parano_oid;
1582        static struct strbuf tmp_file = STRBUF_INIT;
1583        static struct strbuf filename = STRBUF_INIT;
1584
1585        strbuf_reset(&filename);
1586        sha1_file_name(&filename, oid->hash);
1587
1588        fd = create_tmpfile(&tmp_file, filename.buf);
1589        if (fd < 0) {
1590                if (errno == EACCES)
1591                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1592                else
1593                        return error_errno("unable to create temporary file");
1594        }
1595
1596        /* Set it up */
1597        git_deflate_init(&stream, zlib_compression_level);
1598        stream.next_out = compressed;
1599        stream.avail_out = sizeof(compressed);
1600        the_hash_algo->init_fn(&c);
1601
1602        /* First header.. */
1603        stream.next_in = (unsigned char *)hdr;
1604        stream.avail_in = hdrlen;
1605        while (git_deflate(&stream, 0) == Z_OK)
1606                ; /* nothing */
1607        the_hash_algo->update_fn(&c, hdr, hdrlen);
1608
1609        /* Then the data itself.. */
1610        stream.next_in = (void *)buf;
1611        stream.avail_in = len;
1612        do {
1613                unsigned char *in0 = stream.next_in;
1614                ret = git_deflate(&stream, Z_FINISH);
1615                the_hash_algo->update_fn(&c, in0, stream.next_in - in0);
1616                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1617                        die("unable to write sha1 file");
1618                stream.next_out = compressed;
1619                stream.avail_out = sizeof(compressed);
1620        } while (ret == Z_OK);
1621
1622        if (ret != Z_STREAM_END)
1623                die("unable to deflate new object %s (%d)", oid_to_hex(oid),
1624                    ret);
1625        ret = git_deflate_end_gently(&stream);
1626        if (ret != Z_OK)
1627                die("deflateEnd on object %s failed (%d)", oid_to_hex(oid),
1628                    ret);
1629        the_hash_algo->final_fn(parano_oid.hash, &c);
1630        if (oidcmp(oid, &parano_oid) != 0)
1631                die("confused by unstable object source data for %s",
1632                    oid_to_hex(oid));
1633
1634        close_sha1_file(fd);
1635
1636        if (mtime) {
1637                struct utimbuf utb;
1638                utb.actime = mtime;
1639                utb.modtime = mtime;
1640                if (utime(tmp_file.buf, &utb) < 0)
1641                        warning_errno("failed utime() on %s", tmp_file.buf);
1642        }
1643
1644        return finalize_object_file(tmp_file.buf, filename.buf);
1645}
1646
1647static int freshen_loose_object(const unsigned char *sha1)
1648{
1649        return check_and_freshen(sha1, 1);
1650}
1651
1652static int freshen_packed_object(const unsigned char *sha1)
1653{
1654        struct pack_entry e;
1655        if (!find_pack_entry(sha1, &e))
1656                return 0;
1657        if (e.p->freshened)
1658                return 1;
1659        if (!freshen_file(e.p->pack_name))
1660                return 0;
1661        e.p->freshened = 1;
1662        return 1;
1663}
1664
1665int write_object_file(const void *buf, unsigned long len, const char *type,
1666                      struct object_id *oid)
1667{
1668        char hdr[32];
1669        int hdrlen = sizeof(hdr);
1670
1671        /* Normally if we have it in the pack then we do not bother writing
1672         * it out into .git/objects/??/?{38} file.
1673         */
1674        write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1675        if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1676                return 0;
1677        return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
1678}
1679
1680int hash_object_file_literally(const void *buf, unsigned long len,
1681                               const char *type, struct object_id *oid,
1682                               unsigned flags)
1683{
1684        char *header;
1685        int hdrlen, status = 0;
1686
1687        /* type string, SP, %lu of the length plus NUL must fit this */
1688        hdrlen = strlen(type) + 32;
1689        header = xmalloc(hdrlen);
1690        write_object_file_prepare(buf, len, type, oid, header, &hdrlen);
1691
1692        if (!(flags & HASH_WRITE_OBJECT))
1693                goto cleanup;
1694        if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1695                goto cleanup;
1696        status = write_loose_object(oid, header, hdrlen, buf, len, 0);
1697
1698cleanup:
1699        free(header);
1700        return status;
1701}
1702
1703int force_object_loose(const struct object_id *oid, time_t mtime)
1704{
1705        void *buf;
1706        unsigned long len;
1707        enum object_type type;
1708        char hdr[32];
1709        int hdrlen;
1710        int ret;
1711
1712        if (has_loose_object(oid->hash))
1713                return 0;
1714        buf = read_object(oid->hash, &type, &len);
1715        if (!buf)
1716                return error("cannot read sha1_file for %s", oid_to_hex(oid));
1717        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", type_name(type), len) + 1;
1718        ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime);
1719        free(buf);
1720
1721        return ret;
1722}
1723
1724int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1725{
1726        if (!startup_info->have_repository)
1727                return 0;
1728        return sha1_object_info_extended(sha1, NULL,
1729                                         flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1730}
1731
1732int has_object_file(const struct object_id *oid)
1733{
1734        return has_sha1_file(oid->hash);
1735}
1736
1737int has_object_file_with_flags(const struct object_id *oid, int flags)
1738{
1739        return has_sha1_file_with_flags(oid->hash, flags);
1740}
1741
1742static void check_tree(const void *buf, size_t size)
1743{
1744        struct tree_desc desc;
1745        struct name_entry entry;
1746
1747        init_tree_desc(&desc, buf, size);
1748        while (tree_entry(&desc, &entry))
1749                /* do nothing
1750                 * tree_entry() will die() on malformed entries */
1751                ;
1752}
1753
1754static void check_commit(const void *buf, size_t size)
1755{
1756        struct commit c;
1757        memset(&c, 0, sizeof(c));
1758        if (parse_commit_buffer(&c, buf, size))
1759                die("corrupt commit");
1760}
1761
1762static void check_tag(const void *buf, size_t size)
1763{
1764        struct tag t;
1765        memset(&t, 0, sizeof(t));
1766        if (parse_tag_buffer(&t, buf, size))
1767                die("corrupt tag");
1768}
1769
1770static int index_mem(struct object_id *oid, void *buf, size_t size,
1771                     enum object_type type,
1772                     const char *path, unsigned flags)
1773{
1774        int ret, re_allocated = 0;
1775        int write_object = flags & HASH_WRITE_OBJECT;
1776
1777        if (!type)
1778                type = OBJ_BLOB;
1779
1780        /*
1781         * Convert blobs to git internal format
1782         */
1783        if ((type == OBJ_BLOB) && path) {
1784                struct strbuf nbuf = STRBUF_INIT;
1785                if (convert_to_git(&the_index, path, buf, size, &nbuf,
1786                                   get_conv_flags(flags))) {
1787                        buf = strbuf_detach(&nbuf, &size);
1788                        re_allocated = 1;
1789                }
1790        }
1791        if (flags & HASH_FORMAT_CHECK) {
1792                if (type == OBJ_TREE)
1793                        check_tree(buf, size);
1794                if (type == OBJ_COMMIT)
1795                        check_commit(buf, size);
1796                if (type == OBJ_TAG)
1797                        check_tag(buf, size);
1798        }
1799
1800        if (write_object)
1801                ret = write_object_file(buf, size, type_name(type), oid);
1802        else
1803                ret = hash_object_file(buf, size, type_name(type), oid);
1804        if (re_allocated)
1805                free(buf);
1806        return ret;
1807}
1808
1809static int index_stream_convert_blob(struct object_id *oid, int fd,
1810                                     const char *path, unsigned flags)
1811{
1812        int ret;
1813        const int write_object = flags & HASH_WRITE_OBJECT;
1814        struct strbuf sbuf = STRBUF_INIT;
1815
1816        assert(path);
1817        assert(would_convert_to_git_filter_fd(path));
1818
1819        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1820                                 get_conv_flags(flags));
1821
1822        if (write_object)
1823                ret = write_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
1824                                        oid);
1825        else
1826                ret = hash_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
1827                                       oid);
1828        strbuf_release(&sbuf);
1829        return ret;
1830}
1831
1832static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1833                      const char *path, unsigned flags)
1834{
1835        struct strbuf sbuf = STRBUF_INIT;
1836        int ret;
1837
1838        if (strbuf_read(&sbuf, fd, 4096) >= 0)
1839                ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1840        else
1841                ret = -1;
1842        strbuf_release(&sbuf);
1843        return ret;
1844}
1845
1846#define SMALL_FILE_SIZE (32*1024)
1847
1848static int index_core(struct object_id *oid, int fd, size_t size,
1849                      enum object_type type, const char *path,
1850                      unsigned flags)
1851{
1852        int ret;
1853
1854        if (!size) {
1855                ret = index_mem(oid, "", size, type, path, flags);
1856        } else if (size <= SMALL_FILE_SIZE) {
1857                char *buf = xmalloc(size);
1858                ssize_t read_result = read_in_full(fd, buf, size);
1859                if (read_result < 0)
1860                        ret = error_errno("read error while indexing %s",
1861                                          path ? path : "<unknown>");
1862                else if (read_result != size)
1863                        ret = error("short read while indexing %s",
1864                                    path ? path : "<unknown>");
1865                else
1866                        ret = index_mem(oid, buf, size, type, path, flags);
1867                free(buf);
1868        } else {
1869                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1870                ret = index_mem(oid, buf, size, type, path, flags);
1871                munmap(buf, size);
1872        }
1873        return ret;
1874}
1875
1876/*
1877 * This creates one packfile per large blob unless bulk-checkin
1878 * machinery is "plugged".
1879 *
1880 * This also bypasses the usual "convert-to-git" dance, and that is on
1881 * purpose. We could write a streaming version of the converting
1882 * functions and insert that before feeding the data to fast-import
1883 * (or equivalent in-core API described above). However, that is
1884 * somewhat complicated, as we do not know the size of the filter
1885 * result, which we need to know beforehand when writing a git object.
1886 * Since the primary motivation for trying to stream from the working
1887 * tree file and to avoid mmaping it in core is to deal with large
1888 * binary blobs, they generally do not want to get any conversion, and
1889 * callers should avoid this code path when filters are requested.
1890 */
1891static int index_stream(struct object_id *oid, int fd, size_t size,
1892                        enum object_type type, const char *path,
1893                        unsigned flags)
1894{
1895        return index_bulk_checkin(oid, fd, size, type, path, flags);
1896}
1897
1898int index_fd(struct object_id *oid, int fd, struct stat *st,
1899             enum object_type type, const char *path, unsigned flags)
1900{
1901        int ret;
1902
1903        /*
1904         * Call xsize_t() only when needed to avoid potentially unnecessary
1905         * die() for large files.
1906         */
1907        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1908                ret = index_stream_convert_blob(oid, fd, path, flags);
1909        else if (!S_ISREG(st->st_mode))
1910                ret = index_pipe(oid, fd, type, path, flags);
1911        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1912                 (path && would_convert_to_git(&the_index, path)))
1913                ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1914                                 flags);
1915        else
1916                ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1917                                   flags);
1918        close(fd);
1919        return ret;
1920}
1921
1922int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1923{
1924        int fd;
1925        struct strbuf sb = STRBUF_INIT;
1926        int rc = 0;
1927
1928        switch (st->st_mode & S_IFMT) {
1929        case S_IFREG:
1930                fd = open(path, O_RDONLY);
1931                if (fd < 0)
1932                        return error_errno("open(\"%s\")", path);
1933                if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1934                        return error("%s: failed to insert into database",
1935                                     path);
1936                break;
1937        case S_IFLNK:
1938                if (strbuf_readlink(&sb, path, st->st_size))
1939                        return error_errno("readlink(\"%s\")", path);
1940                if (!(flags & HASH_WRITE_OBJECT))
1941                        hash_object_file(sb.buf, sb.len, blob_type, oid);
1942                else if (write_object_file(sb.buf, sb.len, blob_type, oid))
1943                        rc = error("%s: failed to insert into database", path);
1944                strbuf_release(&sb);
1945                break;
1946        case S_IFDIR:
1947                return resolve_gitlink_ref(path, "HEAD", oid);
1948        default:
1949                return error("%s: unsupported file type", path);
1950        }
1951        return rc;
1952}
1953
1954int read_pack_header(int fd, struct pack_header *header)
1955{
1956        if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1957                /* "eof before pack header was fully read" */
1958                return PH_ERROR_EOF;
1959
1960        if (header->hdr_signature != htonl(PACK_SIGNATURE))
1961                /* "protocol error (pack signature mismatch detected)" */
1962                return PH_ERROR_PACK_SIGNATURE;
1963        if (!pack_version_ok(header->hdr_version))
1964                /* "protocol error (pack version unsupported)" */
1965                return PH_ERROR_PROTOCOL;
1966        return 0;
1967}
1968
1969void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1970{
1971        enum object_type type = sha1_object_info(sha1, NULL);
1972        if (type < 0)
1973                die("%s is not a valid object", sha1_to_hex(sha1));
1974        if (type != expect)
1975                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1976                    type_name(expect));
1977}
1978
1979int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1980                                struct strbuf *path,
1981                                each_loose_object_fn obj_cb,
1982                                each_loose_cruft_fn cruft_cb,
1983                                each_loose_subdir_fn subdir_cb,
1984                                void *data)
1985{
1986        size_t origlen, baselen;
1987        DIR *dir;
1988        struct dirent *de;
1989        int r = 0;
1990        struct object_id oid;
1991
1992        if (subdir_nr > 0xff)
1993                BUG("invalid loose object subdirectory: %x", subdir_nr);
1994
1995        origlen = path->len;
1996        strbuf_complete(path, '/');
1997        strbuf_addf(path, "%02x", subdir_nr);
1998
1999        dir = opendir(path->buf);
2000        if (!dir) {
2001                if (errno != ENOENT)
2002                        r = error_errno("unable to open %s", path->buf);
2003                strbuf_setlen(path, origlen);
2004                return r;
2005        }
2006
2007        oid.hash[0] = subdir_nr;
2008        strbuf_addch(path, '/');
2009        baselen = path->len;
2010
2011        while ((de = readdir(dir))) {
2012                size_t namelen;
2013                if (is_dot_or_dotdot(de->d_name))
2014                        continue;
2015
2016                namelen = strlen(de->d_name);
2017                strbuf_setlen(path, baselen);
2018                strbuf_add(path, de->d_name, namelen);
2019                if (namelen == GIT_SHA1_HEXSZ - 2 &&
2020                    !hex_to_bytes(oid.hash + 1, de->d_name,
2021                                  GIT_SHA1_RAWSZ - 1)) {
2022                        if (obj_cb) {
2023                                r = obj_cb(&oid, path->buf, data);
2024                                if (r)
2025                                        break;
2026                        }
2027                        continue;
2028                }
2029
2030                if (cruft_cb) {
2031                        r = cruft_cb(de->d_name, path->buf, data);
2032                        if (r)
2033                                break;
2034                }
2035        }
2036        closedir(dir);
2037
2038        strbuf_setlen(path, baselen - 1);
2039        if (!r && subdir_cb)
2040                r = subdir_cb(subdir_nr, path->buf, data);
2041
2042        strbuf_setlen(path, origlen);
2043
2044        return r;
2045}
2046
2047int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2048                            each_loose_object_fn obj_cb,
2049                            each_loose_cruft_fn cruft_cb,
2050                            each_loose_subdir_fn subdir_cb,
2051                            void *data)
2052{
2053        int r = 0;
2054        int i;
2055
2056        for (i = 0; i < 256; i++) {
2057                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2058                                                subdir_cb, data);
2059                if (r)
2060                        break;
2061        }
2062
2063        return r;
2064}
2065
2066int for_each_loose_file_in_objdir(const char *path,
2067                                  each_loose_object_fn obj_cb,
2068                                  each_loose_cruft_fn cruft_cb,
2069                                  each_loose_subdir_fn subdir_cb,
2070                                  void *data)
2071{
2072        struct strbuf buf = STRBUF_INIT;
2073        int r;
2074
2075        strbuf_addstr(&buf, path);
2076        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2077                                              subdir_cb, data);
2078        strbuf_release(&buf);
2079
2080        return r;
2081}
2082
2083struct loose_alt_odb_data {
2084        each_loose_object_fn *cb;
2085        void *data;
2086};
2087
2088static int loose_from_alt_odb(struct alternate_object_database *alt,
2089                              void *vdata)
2090{
2091        struct loose_alt_odb_data *data = vdata;
2092        struct strbuf buf = STRBUF_INIT;
2093        int r;
2094
2095        strbuf_addstr(&buf, alt->path);
2096        r = for_each_loose_file_in_objdir_buf(&buf,
2097                                              data->cb, NULL, NULL,
2098                                              data->data);
2099        strbuf_release(&buf);
2100        return r;
2101}
2102
2103int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2104{
2105        struct loose_alt_odb_data alt;
2106        int r;
2107
2108        r = for_each_loose_file_in_objdir(get_object_directory(),
2109                                          cb, NULL, NULL, data);
2110        if (r)
2111                return r;
2112
2113        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2114                return 0;
2115
2116        alt.cb = cb;
2117        alt.data = data;
2118        return foreach_alt_odb(loose_from_alt_odb, &alt);
2119}
2120
2121static int check_stream_sha1(git_zstream *stream,
2122                             const char *hdr,
2123                             unsigned long size,
2124                             const char *path,
2125                             const unsigned char *expected_sha1)
2126{
2127        git_hash_ctx c;
2128        unsigned char real_sha1[GIT_MAX_RAWSZ];
2129        unsigned char buf[4096];
2130        unsigned long total_read;
2131        int status = Z_OK;
2132
2133        the_hash_algo->init_fn(&c);
2134        the_hash_algo->update_fn(&c, hdr, stream->total_out);
2135
2136        /*
2137         * We already read some bytes into hdr, but the ones up to the NUL
2138         * do not count against the object's content size.
2139         */
2140        total_read = stream->total_out - strlen(hdr) - 1;
2141
2142        /*
2143         * This size comparison must be "<=" to read the final zlib packets;
2144         * see the comment in unpack_sha1_rest for details.
2145         */
2146        while (total_read <= size &&
2147               (status == Z_OK || status == Z_BUF_ERROR)) {
2148                stream->next_out = buf;
2149                stream->avail_out = sizeof(buf);
2150                if (size - total_read < stream->avail_out)
2151                        stream->avail_out = size - total_read;
2152                status = git_inflate(stream, Z_FINISH);
2153                the_hash_algo->update_fn(&c, buf, stream->next_out - buf);
2154                total_read += stream->next_out - buf;
2155        }
2156        git_inflate_end(stream);
2157
2158        if (status != Z_STREAM_END) {
2159                error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2160                return -1;
2161        }
2162        if (stream->avail_in) {
2163                error("garbage at end of loose object '%s'",
2164                      sha1_to_hex(expected_sha1));
2165                return -1;
2166        }
2167
2168        the_hash_algo->final_fn(real_sha1, &c);
2169        if (hashcmp(expected_sha1, real_sha1)) {
2170                error("sha1 mismatch for %s (expected %s)", path,
2171                      sha1_to_hex(expected_sha1));
2172                return -1;
2173        }
2174
2175        return 0;
2176}
2177
2178int read_loose_object(const char *path,
2179                      const unsigned char *expected_sha1,
2180                      enum object_type *type,
2181                      unsigned long *size,
2182                      void **contents)
2183{
2184        int ret = -1;
2185        void *map = NULL;
2186        unsigned long mapsize;
2187        git_zstream stream;
2188        char hdr[32];
2189
2190        *contents = NULL;
2191
2192        map = map_sha1_file_1(path, NULL, &mapsize);
2193        if (!map) {
2194                error_errno("unable to mmap %s", path);
2195                goto out;
2196        }
2197
2198        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2199                error("unable to unpack header of %s", path);
2200                goto out;
2201        }
2202
2203        *type = parse_sha1_header(hdr, size);
2204        if (*type < 0) {
2205                error("unable to parse header of %s", path);
2206                git_inflate_end(&stream);
2207                goto out;
2208        }
2209
2210        if (*type == OBJ_BLOB) {
2211                if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2212                        goto out;
2213        } else {
2214                *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2215                if (!*contents) {
2216                        error("unable to unpack contents of %s", path);
2217                        git_inflate_end(&stream);
2218                        goto out;
2219                }
2220                if (check_sha1_signature(expected_sha1, *contents,
2221                                         *size, type_name(*type))) {
2222                        error("sha1 mismatch for %s (expected %s)", path,
2223                              sha1_to_hex(expected_sha1));
2224                        free(*contents);
2225                        goto out;
2226                }
2227        }
2228
2229        ret = 0; /* everything checks out */
2230
2231out:
2232        if (map)
2233                munmap(map, mapsize);
2234        return ret;
2235}