af3f1e5c5302a5f3df13d760696187be76da11ec
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This handles basic git sha1 object files - packing, unpacking,
   7 * creation etc.
   8 */
   9#include "cache.h"
  10#include "config.h"
  11#include "string-list.h"
  12#include "lockfile.h"
  13#include "delta.h"
  14#include "pack.h"
  15#include "blob.h"
  16#include "commit.h"
  17#include "run-command.h"
  18#include "tag.h"
  19#include "tree.h"
  20#include "tree-walk.h"
  21#include "refs.h"
  22#include "pack-revindex.h"
  23#include "sha1-lookup.h"
  24#include "bulk-checkin.h"
  25#include "streaming.h"
  26#include "dir.h"
  27#include "mru.h"
  28#include "list.h"
  29#include "mergesort.h"
  30#include "quote.h"
  31#include "packfile.h"
  32
  33const unsigned char null_sha1[20];
  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
  42/*
  43 * This is meant to hold a *small* number of objects that you would
  44 * want read_sha1_file() to be able to return, but yet you do not want
  45 * to write them into the object store (e.g. a browse-only
  46 * application).
  47 */
  48static struct cached_object {
  49        unsigned char sha1[20];
  50        enum object_type type;
  51        void *buf;
  52        unsigned long size;
  53} *cached_objects;
  54static int cached_object_nr, cached_object_alloc;
  55
  56static struct cached_object empty_tree = {
  57        EMPTY_TREE_SHA1_BIN_LITERAL,
  58        OBJ_TREE,
  59        "",
  60        0
  61};
  62
  63static struct cached_object *find_cached_object(const unsigned char *sha1)
  64{
  65        int i;
  66        struct cached_object *co = cached_objects;
  67
  68        for (i = 0; i < cached_object_nr; i++, co++) {
  69                if (!hashcmp(co->sha1, sha1))
  70                        return co;
  71        }
  72        if (!hashcmp(sha1, empty_tree.sha1))
  73                return &empty_tree;
  74        return NULL;
  75}
  76
  77int mkdir_in_gitdir(const char *path)
  78{
  79        if (mkdir(path, 0777)) {
  80                int saved_errno = errno;
  81                struct stat st;
  82                struct strbuf sb = STRBUF_INIT;
  83
  84                if (errno != EEXIST)
  85                        return -1;
  86                /*
  87                 * Are we looking at a path in a symlinked worktree
  88                 * whose original repository does not yet have it?
  89                 * e.g. .git/rr-cache pointing at its original
  90                 * repository in which the user hasn't performed any
  91                 * conflict resolution yet?
  92                 */
  93                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
  94                    strbuf_readlink(&sb, path, st.st_size) ||
  95                    !is_absolute_path(sb.buf) ||
  96                    mkdir(sb.buf, 0777)) {
  97                        strbuf_release(&sb);
  98                        errno = saved_errno;
  99                        return -1;
 100                }
 101                strbuf_release(&sb);
 102        }
 103        return adjust_shared_perm(path);
 104}
 105
 106enum scld_error safe_create_leading_directories(char *path)
 107{
 108        char *next_component = path + offset_1st_component(path);
 109        enum scld_error ret = SCLD_OK;
 110
 111        while (ret == SCLD_OK && next_component) {
 112                struct stat st;
 113                char *slash = next_component, slash_character;
 114
 115                while (*slash && !is_dir_sep(*slash))
 116                        slash++;
 117
 118                if (!*slash)
 119                        break;
 120
 121                next_component = slash + 1;
 122                while (is_dir_sep(*next_component))
 123                        next_component++;
 124                if (!*next_component)
 125                        break;
 126
 127                slash_character = *slash;
 128                *slash = '\0';
 129                if (!stat(path, &st)) {
 130                        /* path exists */
 131                        if (!S_ISDIR(st.st_mode)) {
 132                                errno = ENOTDIR;
 133                                ret = SCLD_EXISTS;
 134                        }
 135                } else if (mkdir(path, 0777)) {
 136                        if (errno == EEXIST &&
 137                            !stat(path, &st) && S_ISDIR(st.st_mode))
 138                                ; /* somebody created it since we checked */
 139                        else if (errno == ENOENT)
 140                                /*
 141                                 * Either mkdir() failed because
 142                                 * somebody just pruned the containing
 143                                 * directory, or stat() failed because
 144                                 * the file that was in our way was
 145                                 * just removed.  Either way, inform
 146                                 * the caller that it might be worth
 147                                 * trying again:
 148                                 */
 149                                ret = SCLD_VANISHED;
 150                        else
 151                                ret = SCLD_FAILED;
 152                } else if (adjust_shared_perm(path)) {
 153                        ret = SCLD_PERMS;
 154                }
 155                *slash = slash_character;
 156        }
 157        return ret;
 158}
 159
 160enum scld_error safe_create_leading_directories_const(const char *path)
 161{
 162        int save_errno;
 163        /* path points to cache entries, so xstrdup before messing with it */
 164        char *buf = xstrdup(path);
 165        enum scld_error result = safe_create_leading_directories(buf);
 166
 167        save_errno = errno;
 168        free(buf);
 169        errno = save_errno;
 170        return result;
 171}
 172
 173int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 174{
 175        /*
 176         * The number of times we will try to remove empty directories
 177         * in the way of path. This is only 1 because if another
 178         * process is racily creating directories that conflict with
 179         * us, we don't want to fight against them.
 180         */
 181        int remove_directories_remaining = 1;
 182
 183        /*
 184         * The number of times that we will try to create the
 185         * directories containing path. We are willing to attempt this
 186         * more than once, because another process could be trying to
 187         * clean up empty directories at the same time as we are
 188         * trying to create them.
 189         */
 190        int create_directories_remaining = 3;
 191
 192        /* A scratch copy of path, filled lazily if we need it: */
 193        struct strbuf path_copy = STRBUF_INIT;
 194
 195        int ret, save_errno;
 196
 197        /* Sanity check: */
 198        assert(*path);
 199
 200retry_fn:
 201        ret = fn(path, cb);
 202        save_errno = errno;
 203        if (!ret)
 204                goto out;
 205
 206        if (errno == EISDIR && remove_directories_remaining-- > 0) {
 207                /*
 208                 * A directory is in the way. Maybe it is empty; try
 209                 * to remove it:
 210                 */
 211                if (!path_copy.len)
 212                        strbuf_addstr(&path_copy, path);
 213
 214                if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 215                        goto retry_fn;
 216        } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 217                /*
 218                 * Maybe the containing directory didn't exist, or
 219                 * maybe it was just deleted by a process that is
 220                 * racing with us to clean up empty directories. Try
 221                 * to create it:
 222                 */
 223                enum scld_error scld_result;
 224
 225                if (!path_copy.len)
 226                        strbuf_addstr(&path_copy, path);
 227
 228                do {
 229                        scld_result = safe_create_leading_directories(path_copy.buf);
 230                        if (scld_result == SCLD_OK)
 231                                goto retry_fn;
 232                } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 233        }
 234
 235out:
 236        strbuf_release(&path_copy);
 237        errno = save_errno;
 238        return ret;
 239}
 240
 241static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 242{
 243        int i;
 244        for (i = 0; i < 20; i++) {
 245                static char hex[] = "0123456789abcdef";
 246                unsigned int val = sha1[i];
 247                strbuf_addch(buf, hex[val >> 4]);
 248                strbuf_addch(buf, hex[val & 0xf]);
 249                if (!i)
 250                        strbuf_addch(buf, '/');
 251        }
 252}
 253
 254const char *sha1_file_name(const unsigned char *sha1)
 255{
 256        static struct strbuf buf = STRBUF_INIT;
 257
 258        strbuf_reset(&buf);
 259        strbuf_addf(&buf, "%s/", get_object_directory());
 260
 261        fill_sha1_path(&buf, sha1);
 262        return buf.buf;
 263}
 264
 265struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 266{
 267        strbuf_setlen(&alt->scratch, alt->base_len);
 268        return &alt->scratch;
 269}
 270
 271static const char *alt_sha1_path(struct alternate_object_database *alt,
 272                                 const unsigned char *sha1)
 273{
 274        struct strbuf *buf = alt_scratch_buf(alt);
 275        fill_sha1_path(buf, sha1);
 276        return buf->buf;
 277}
 278
 279struct alternate_object_database *alt_odb_list;
 280static struct alternate_object_database **alt_odb_tail;
 281
 282/*
 283 * Return non-zero iff the path is usable as an alternate object database.
 284 */
 285static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 286{
 287        struct alternate_object_database *alt;
 288
 289        /* Detect cases where alternate disappeared */
 290        if (!is_directory(path->buf)) {
 291                error("object directory %s does not exist; "
 292                      "check .git/objects/info/alternates.",
 293                      path->buf);
 294                return 0;
 295        }
 296
 297        /*
 298         * Prevent the common mistake of listing the same
 299         * thing twice, or object directory itself.
 300         */
 301        for (alt = alt_odb_list; alt; alt = alt->next) {
 302                if (!fspathcmp(path->buf, alt->path))
 303                        return 0;
 304        }
 305        if (!fspathcmp(path->buf, normalized_objdir))
 306                return 0;
 307
 308        return 1;
 309}
 310
 311/*
 312 * Prepare alternate object database registry.
 313 *
 314 * The variable alt_odb_list points at the list of struct
 315 * alternate_object_database.  The elements on this list come from
 316 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 317 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 318 * whose contents is similar to that environment variable but can be
 319 * LF separated.  Its base points at a statically allocated buffer that
 320 * contains "/the/directory/corresponding/to/.git/objects/...", while
 321 * its name points just after the slash at the end of ".git/objects/"
 322 * in the example above, and has enough space to hold 40-byte hex
 323 * SHA1, an extra slash for the first level indirection, and the
 324 * terminating NUL.
 325 */
 326static void read_info_alternates(const char * relative_base, int depth);
 327static int link_alt_odb_entry(const char *entry, const char *relative_base,
 328        int depth, const char *normalized_objdir)
 329{
 330        struct alternate_object_database *ent;
 331        struct strbuf pathbuf = STRBUF_INIT;
 332
 333        if (!is_absolute_path(entry) && relative_base) {
 334                strbuf_realpath(&pathbuf, relative_base, 1);
 335                strbuf_addch(&pathbuf, '/');
 336        }
 337        strbuf_addstr(&pathbuf, entry);
 338
 339        if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 340                error("unable to normalize alternate object path: %s",
 341                      pathbuf.buf);
 342                strbuf_release(&pathbuf);
 343                return -1;
 344        }
 345
 346        /*
 347         * The trailing slash after the directory name is given by
 348         * this function at the end. Remove duplicates.
 349         */
 350        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 351                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 352
 353        if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 354                strbuf_release(&pathbuf);
 355                return -1;
 356        }
 357
 358        ent = alloc_alt_odb(pathbuf.buf);
 359
 360        /* add the alternate entry */
 361        *alt_odb_tail = ent;
 362        alt_odb_tail = &(ent->next);
 363        ent->next = NULL;
 364
 365        /* recursively add alternates */
 366        read_info_alternates(pathbuf.buf, depth + 1);
 367
 368        strbuf_release(&pathbuf);
 369        return 0;
 370}
 371
 372static const char *parse_alt_odb_entry(const char *string,
 373                                       int sep,
 374                                       struct strbuf *out)
 375{
 376        const char *end;
 377
 378        strbuf_reset(out);
 379
 380        if (*string == '#') {
 381                /* comment; consume up to next separator */
 382                end = strchrnul(string, sep);
 383        } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 384                /*
 385                 * quoted path; unquote_c_style has copied the
 386                 * data for us and set "end". Broken quoting (e.g.,
 387                 * an entry that doesn't end with a quote) falls
 388                 * back to the unquoted case below.
 389                 */
 390        } else {
 391                /* normal, unquoted path */
 392                end = strchrnul(string, sep);
 393                strbuf_add(out, string, end - string);
 394        }
 395
 396        if (*end)
 397                end++;
 398        return end;
 399}
 400
 401static void link_alt_odb_entries(const char *alt, int len, int sep,
 402                                 const char *relative_base, int depth)
 403{
 404        struct strbuf objdirbuf = STRBUF_INIT;
 405        struct strbuf entry = STRBUF_INIT;
 406
 407        if (depth > 5) {
 408                error("%s: ignoring alternate object stores, nesting too deep.",
 409                                relative_base);
 410                return;
 411        }
 412
 413        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 414        if (strbuf_normalize_path(&objdirbuf) < 0)
 415                die("unable to normalize object directory: %s",
 416                    objdirbuf.buf);
 417
 418        while (*alt) {
 419                alt = parse_alt_odb_entry(alt, sep, &entry);
 420                if (!entry.len)
 421                        continue;
 422                link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 423        }
 424        strbuf_release(&entry);
 425        strbuf_release(&objdirbuf);
 426}
 427
 428static void read_info_alternates(const char * relative_base, int depth)
 429{
 430        char *map;
 431        size_t mapsz;
 432        struct stat st;
 433        char *path;
 434        int fd;
 435
 436        path = xstrfmt("%s/info/alternates", relative_base);
 437        fd = git_open(path);
 438        free(path);
 439        if (fd < 0)
 440                return;
 441        if (fstat(fd, &st) || (st.st_size == 0)) {
 442                close(fd);
 443                return;
 444        }
 445        mapsz = xsize_t(st.st_size);
 446        map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 447        close(fd);
 448
 449        link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
 450
 451        munmap(map, mapsz);
 452}
 453
 454struct alternate_object_database *alloc_alt_odb(const char *dir)
 455{
 456        struct alternate_object_database *ent;
 457
 458        FLEX_ALLOC_STR(ent, path, dir);
 459        strbuf_init(&ent->scratch, 0);
 460        strbuf_addf(&ent->scratch, "%s/", dir);
 461        ent->base_len = ent->scratch.len;
 462
 463        return ent;
 464}
 465
 466void add_to_alternates_file(const char *reference)
 467{
 468        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 469        char *alts = git_pathdup("objects/info/alternates");
 470        FILE *in, *out;
 471
 472        hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
 473        out = fdopen_lock_file(lock, "w");
 474        if (!out)
 475                die_errno("unable to fdopen alternates lockfile");
 476
 477        in = fopen(alts, "r");
 478        if (in) {
 479                struct strbuf line = STRBUF_INIT;
 480                int found = 0;
 481
 482                while (strbuf_getline(&line, in) != EOF) {
 483                        if (!strcmp(reference, line.buf)) {
 484                                found = 1;
 485                                break;
 486                        }
 487                        fprintf_or_die(out, "%s\n", line.buf);
 488                }
 489
 490                strbuf_release(&line);
 491                fclose(in);
 492
 493                if (found) {
 494                        rollback_lock_file(lock);
 495                        lock = NULL;
 496                }
 497        }
 498        else if (errno != ENOENT)
 499                die_errno("unable to read alternates file");
 500
 501        if (lock) {
 502                fprintf_or_die(out, "%s\n", reference);
 503                if (commit_lock_file(lock))
 504                        die_errno("unable to move new alternates file into place");
 505                if (alt_odb_tail)
 506                        link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 507        }
 508        free(alts);
 509}
 510
 511void add_to_alternates_memory(const char *reference)
 512{
 513        /*
 514         * Make sure alternates are initialized, or else our entry may be
 515         * overwritten when they are.
 516         */
 517        prepare_alt_odb();
 518
 519        link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 520}
 521
 522/*
 523 * Compute the exact path an alternate is at and returns it. In case of
 524 * error NULL is returned and the human readable error is added to `err`
 525 * `path` may be relative and should point to $GITDIR.
 526 * `err` must not be null.
 527 */
 528char *compute_alternate_path(const char *path, struct strbuf *err)
 529{
 530        char *ref_git = NULL;
 531        const char *repo, *ref_git_s;
 532        int seen_error = 0;
 533
 534        ref_git_s = real_path_if_valid(path);
 535        if (!ref_git_s) {
 536                seen_error = 1;
 537                strbuf_addf(err, _("path '%s' does not exist"), path);
 538                goto out;
 539        } else
 540                /*
 541                 * Beware: read_gitfile(), real_path() and mkpath()
 542                 * return static buffer
 543                 */
 544                ref_git = xstrdup(ref_git_s);
 545
 546        repo = read_gitfile(ref_git);
 547        if (!repo)
 548                repo = read_gitfile(mkpath("%s/.git", ref_git));
 549        if (repo) {
 550                free(ref_git);
 551                ref_git = xstrdup(repo);
 552        }
 553
 554        if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 555                char *ref_git_git = mkpathdup("%s/.git", ref_git);
 556                free(ref_git);
 557                ref_git = ref_git_git;
 558        } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 559                struct strbuf sb = STRBUF_INIT;
 560                seen_error = 1;
 561                if (get_common_dir(&sb, ref_git)) {
 562                        strbuf_addf(err,
 563                                    _("reference repository '%s' as a linked "
 564                                      "checkout is not supported yet."),
 565                                    path);
 566                        goto out;
 567                }
 568
 569                strbuf_addf(err, _("reference repository '%s' is not a "
 570                                        "local repository."), path);
 571                goto out;
 572        }
 573
 574        if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 575                strbuf_addf(err, _("reference repository '%s' is shallow"),
 576                            path);
 577                seen_error = 1;
 578                goto out;
 579        }
 580
 581        if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 582                strbuf_addf(err,
 583                            _("reference repository '%s' is grafted"),
 584                            path);
 585                seen_error = 1;
 586                goto out;
 587        }
 588
 589out:
 590        if (seen_error) {
 591                FREE_AND_NULL(ref_git);
 592        }
 593
 594        return ref_git;
 595}
 596
 597int foreach_alt_odb(alt_odb_fn fn, void *cb)
 598{
 599        struct alternate_object_database *ent;
 600        int r = 0;
 601
 602        prepare_alt_odb();
 603        for (ent = alt_odb_list; ent; ent = ent->next) {
 604                r = fn(ent, cb);
 605                if (r)
 606                        break;
 607        }
 608        return r;
 609}
 610
 611void prepare_alt_odb(void)
 612{
 613        const char *alt;
 614
 615        if (alt_odb_tail)
 616                return;
 617
 618        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 619        if (!alt) alt = "";
 620
 621        alt_odb_tail = &alt_odb_list;
 622        link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
 623
 624        read_info_alternates(get_object_directory(), 0);
 625}
 626
 627/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 628static int freshen_file(const char *fn)
 629{
 630        struct utimbuf t;
 631        t.actime = t.modtime = time(NULL);
 632        return !utime(fn, &t);
 633}
 634
 635/*
 636 * All of the check_and_freshen functions return 1 if the file exists and was
 637 * freshened (if freshening was requested), 0 otherwise. If they return
 638 * 0, you should not assume that it is safe to skip a write of the object (it
 639 * either does not exist on disk, or has a stale mtime and may be subject to
 640 * pruning).
 641 */
 642int check_and_freshen_file(const char *fn, int freshen)
 643{
 644        if (access(fn, F_OK))
 645                return 0;
 646        if (freshen && !freshen_file(fn))
 647                return 0;
 648        return 1;
 649}
 650
 651static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 652{
 653        return check_and_freshen_file(sha1_file_name(sha1), freshen);
 654}
 655
 656static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 657{
 658        struct alternate_object_database *alt;
 659        prepare_alt_odb();
 660        for (alt = alt_odb_list; alt; alt = alt->next) {
 661                const char *path = alt_sha1_path(alt, sha1);
 662                if (check_and_freshen_file(path, freshen))
 663                        return 1;
 664        }
 665        return 0;
 666}
 667
 668static int check_and_freshen(const unsigned char *sha1, int freshen)
 669{
 670        return check_and_freshen_local(sha1, freshen) ||
 671               check_and_freshen_nonlocal(sha1, freshen);
 672}
 673
 674int has_loose_object_nonlocal(const unsigned char *sha1)
 675{
 676        return check_and_freshen_nonlocal(sha1, 0);
 677}
 678
 679static int has_loose_object(const unsigned char *sha1)
 680{
 681        return check_and_freshen(sha1, 0);
 682}
 683
 684static void mmap_limit_check(size_t length)
 685{
 686        static size_t limit = 0;
 687        if (!limit) {
 688                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 689                if (!limit)
 690                        limit = SIZE_MAX;
 691        }
 692        if (length > limit)
 693                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 694                    (uintmax_t)length, (uintmax_t)limit);
 695}
 696
 697void *xmmap_gently(void *start, size_t length,
 698                  int prot, int flags, int fd, off_t offset)
 699{
 700        void *ret;
 701
 702        mmap_limit_check(length);
 703        ret = mmap(start, length, prot, flags, fd, offset);
 704        if (ret == MAP_FAILED) {
 705                if (!length)
 706                        return NULL;
 707                release_pack_memory(length);
 708                ret = mmap(start, length, prot, flags, fd, offset);
 709        }
 710        return ret;
 711}
 712
 713void *xmmap(void *start, size_t length,
 714        int prot, int flags, int fd, off_t offset)
 715{
 716        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 717        if (ret == MAP_FAILED)
 718                die_errno("mmap failed");
 719        return ret;
 720}
 721
 722/*
 723 * With an in-core object data in "map", rehash it to make sure the
 724 * object name actually matches "sha1" to detect object corruption.
 725 * With "map" == NULL, try reading the object named with "sha1" using
 726 * the streaming interface and rehash it to do the same.
 727 */
 728int check_sha1_signature(const unsigned char *sha1, void *map,
 729                         unsigned long size, const char *type)
 730{
 731        unsigned char real_sha1[20];
 732        enum object_type obj_type;
 733        struct git_istream *st;
 734        git_SHA_CTX c;
 735        char hdr[32];
 736        int hdrlen;
 737
 738        if (map) {
 739                hash_sha1_file(map, size, type, real_sha1);
 740                return hashcmp(sha1, real_sha1) ? -1 : 0;
 741        }
 742
 743        st = open_istream(sha1, &obj_type, &size, NULL);
 744        if (!st)
 745                return -1;
 746
 747        /* Generate the header */
 748        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 749
 750        /* Sha1.. */
 751        git_SHA1_Init(&c);
 752        git_SHA1_Update(&c, hdr, hdrlen);
 753        for (;;) {
 754                char buf[1024 * 16];
 755                ssize_t readlen = read_istream(st, buf, sizeof(buf));
 756
 757                if (readlen < 0) {
 758                        close_istream(st);
 759                        return -1;
 760                }
 761                if (!readlen)
 762                        break;
 763                git_SHA1_Update(&c, buf, readlen);
 764        }
 765        git_SHA1_Final(real_sha1, &c);
 766        close_istream(st);
 767        return hashcmp(sha1, real_sha1) ? -1 : 0;
 768}
 769
 770int git_open_cloexec(const char *name, int flags)
 771{
 772        int fd;
 773        static int o_cloexec = O_CLOEXEC;
 774
 775        fd = open(name, flags | o_cloexec);
 776        if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 777                /* Try again w/o O_CLOEXEC: the kernel might not support it */
 778                o_cloexec &= ~O_CLOEXEC;
 779                fd = open(name, flags | o_cloexec);
 780        }
 781
 782#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 783        {
 784                static int fd_cloexec = FD_CLOEXEC;
 785
 786                if (!o_cloexec && 0 <= fd && fd_cloexec) {
 787                        /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 788                        int flags = fcntl(fd, F_GETFD);
 789                        if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 790                                fd_cloexec = 0;
 791                }
 792        }
 793#endif
 794        return fd;
 795}
 796
 797/*
 798 * Find "sha1" as a loose object in the local repository or in an alternate.
 799 * Returns 0 on success, negative on failure.
 800 *
 801 * The "path" out-parameter will give the path of the object we found (if any).
 802 * Note that it may point to static storage and is only valid until another
 803 * call to sha1_file_name(), etc.
 804 */
 805static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 806                          const char **path)
 807{
 808        struct alternate_object_database *alt;
 809
 810        *path = sha1_file_name(sha1);
 811        if (!lstat(*path, st))
 812                return 0;
 813
 814        prepare_alt_odb();
 815        errno = ENOENT;
 816        for (alt = alt_odb_list; alt; alt = alt->next) {
 817                *path = alt_sha1_path(alt, sha1);
 818                if (!lstat(*path, st))
 819                        return 0;
 820        }
 821
 822        return -1;
 823}
 824
 825/*
 826 * Like stat_sha1_file(), but actually open the object and return the
 827 * descriptor. See the caveats on the "path" parameter above.
 828 */
 829static int open_sha1_file(const unsigned char *sha1, const char **path)
 830{
 831        int fd;
 832        struct alternate_object_database *alt;
 833        int most_interesting_errno;
 834
 835        *path = sha1_file_name(sha1);
 836        fd = git_open(*path);
 837        if (fd >= 0)
 838                return fd;
 839        most_interesting_errno = errno;
 840
 841        prepare_alt_odb();
 842        for (alt = alt_odb_list; alt; alt = alt->next) {
 843                *path = alt_sha1_path(alt, sha1);
 844                fd = git_open(*path);
 845                if (fd >= 0)
 846                        return fd;
 847                if (most_interesting_errno == ENOENT)
 848                        most_interesting_errno = errno;
 849        }
 850        errno = most_interesting_errno;
 851        return -1;
 852}
 853
 854/*
 855 * Map the loose object at "path" if it is not NULL, or the path found by
 856 * searching for a loose object named "sha1".
 857 */
 858static void *map_sha1_file_1(const char *path,
 859                             const unsigned char *sha1,
 860                             unsigned long *size)
 861{
 862        void *map;
 863        int fd;
 864
 865        if (path)
 866                fd = git_open(path);
 867        else
 868                fd = open_sha1_file(sha1, &path);
 869        map = NULL;
 870        if (fd >= 0) {
 871                struct stat st;
 872
 873                if (!fstat(fd, &st)) {
 874                        *size = xsize_t(st.st_size);
 875                        if (!*size) {
 876                                /* mmap() is forbidden on empty files */
 877                                error("object file %s is empty", path);
 878                                return NULL;
 879                        }
 880                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 881                }
 882                close(fd);
 883        }
 884        return map;
 885}
 886
 887void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 888{
 889        return map_sha1_file_1(NULL, sha1, size);
 890}
 891
 892static int unpack_sha1_short_header(git_zstream *stream,
 893                                    unsigned char *map, unsigned long mapsize,
 894                                    void *buffer, unsigned long bufsiz)
 895{
 896        /* Get the data stream */
 897        memset(stream, 0, sizeof(*stream));
 898        stream->next_in = map;
 899        stream->avail_in = mapsize;
 900        stream->next_out = buffer;
 901        stream->avail_out = bufsiz;
 902
 903        git_inflate_init(stream);
 904        return git_inflate(stream, 0);
 905}
 906
 907int unpack_sha1_header(git_zstream *stream,
 908                       unsigned char *map, unsigned long mapsize,
 909                       void *buffer, unsigned long bufsiz)
 910{
 911        int status = unpack_sha1_short_header(stream, map, mapsize,
 912                                              buffer, bufsiz);
 913
 914        if (status < Z_OK)
 915                return status;
 916
 917        /* Make sure we have the terminating NUL */
 918        if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 919                return -1;
 920        return 0;
 921}
 922
 923static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 924                                        unsigned long mapsize, void *buffer,
 925                                        unsigned long bufsiz, struct strbuf *header)
 926{
 927        int status;
 928
 929        status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 930        if (status < Z_OK)
 931                return -1;
 932
 933        /*
 934         * Check if entire header is unpacked in the first iteration.
 935         */
 936        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 937                return 0;
 938
 939        /*
 940         * buffer[0..bufsiz] was not large enough.  Copy the partial
 941         * result out to header, and then append the result of further
 942         * reading the stream.
 943         */
 944        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 945        stream->next_out = buffer;
 946        stream->avail_out = bufsiz;
 947
 948        do {
 949                status = git_inflate(stream, 0);
 950                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 951                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 952                        return 0;
 953                stream->next_out = buffer;
 954                stream->avail_out = bufsiz;
 955        } while (status != Z_STREAM_END);
 956        return -1;
 957}
 958
 959static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 960{
 961        int bytes = strlen(buffer) + 1;
 962        unsigned char *buf = xmallocz(size);
 963        unsigned long n;
 964        int status = Z_OK;
 965
 966        n = stream->total_out - bytes;
 967        if (n > size)
 968                n = size;
 969        memcpy(buf, (char *) buffer + bytes, n);
 970        bytes = n;
 971        if (bytes <= size) {
 972                /*
 973                 * The above condition must be (bytes <= size), not
 974                 * (bytes < size).  In other words, even though we
 975                 * expect no more output and set avail_out to zero,
 976                 * the input zlib stream may have bytes that express
 977                 * "this concludes the stream", and we *do* want to
 978                 * eat that input.
 979                 *
 980                 * Otherwise we would not be able to test that we
 981                 * consumed all the input to reach the expected size;
 982                 * we also want to check that zlib tells us that all
 983                 * went well with status == Z_STREAM_END at the end.
 984                 */
 985                stream->next_out = buf + bytes;
 986                stream->avail_out = size - bytes;
 987                while (status == Z_OK)
 988                        status = git_inflate(stream, Z_FINISH);
 989        }
 990        if (status == Z_STREAM_END && !stream->avail_in) {
 991                git_inflate_end(stream);
 992                return buf;
 993        }
 994
 995        if (status < 0)
 996                error("corrupt loose object '%s'", sha1_to_hex(sha1));
 997        else if (stream->avail_in)
 998                error("garbage at end of loose object '%s'",
 999                      sha1_to_hex(sha1));
1000        free(buf);
1001        return NULL;
1002}
1003
1004/*
1005 * We used to just use "sscanf()", but that's actually way
1006 * too permissive for what we want to check. So do an anal
1007 * object header parse by hand.
1008 */
1009static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1010                               unsigned int flags)
1011{
1012        const char *type_buf = hdr;
1013        unsigned long size;
1014        int type, type_len = 0;
1015
1016        /*
1017         * The type can be of any size but is followed by
1018         * a space.
1019         */
1020        for (;;) {
1021                char c = *hdr++;
1022                if (!c)
1023                        return -1;
1024                if (c == ' ')
1025                        break;
1026                type_len++;
1027        }
1028
1029        type = type_from_string_gently(type_buf, type_len, 1);
1030        if (oi->typename)
1031                strbuf_add(oi->typename, type_buf, type_len);
1032        /*
1033         * Set type to 0 if its an unknown object and
1034         * we're obtaining the type using '--allow-unknown-type'
1035         * option.
1036         */
1037        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1038                type = 0;
1039        else if (type < 0)
1040                die("invalid object type");
1041        if (oi->typep)
1042                *oi->typep = type;
1043
1044        /*
1045         * The length must follow immediately, and be in canonical
1046         * decimal format (ie "010" is not valid).
1047         */
1048        size = *hdr++ - '0';
1049        if (size > 9)
1050                return -1;
1051        if (size) {
1052                for (;;) {
1053                        unsigned long c = *hdr - '0';
1054                        if (c > 9)
1055                                break;
1056                        hdr++;
1057                        size = size * 10 + c;
1058                }
1059        }
1060
1061        if (oi->sizep)
1062                *oi->sizep = size;
1063
1064        /*
1065         * The length must be followed by a zero byte
1066         */
1067        return *hdr ? -1 : type;
1068}
1069
1070int parse_sha1_header(const char *hdr, unsigned long *sizep)
1071{
1072        struct object_info oi = OBJECT_INFO_INIT;
1073
1074        oi.sizep = sizep;
1075        return parse_sha1_header_extended(hdr, &oi, 0);
1076}
1077
1078static int fill_pack_entry(const unsigned char *sha1,
1079                           struct pack_entry *e,
1080                           struct packed_git *p)
1081{
1082        off_t offset;
1083
1084        if (p->num_bad_objects) {
1085                unsigned i;
1086                for (i = 0; i < p->num_bad_objects; i++)
1087                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1088                                return 0;
1089        }
1090
1091        offset = find_pack_entry_one(sha1, p);
1092        if (!offset)
1093                return 0;
1094
1095        /*
1096         * We are about to tell the caller where they can locate the
1097         * requested object.  We better make sure the packfile is
1098         * still here and can be accessed before supplying that
1099         * answer, as it may have been deleted since the index was
1100         * loaded!
1101         */
1102        if (!is_pack_valid(p))
1103                return 0;
1104        e->offset = offset;
1105        e->p = p;
1106        hashcpy(e->sha1, sha1);
1107        return 1;
1108}
1109
1110/*
1111 * Iff a pack file contains the object named by sha1, return true and
1112 * store its location to e.
1113 */
1114static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
1115{
1116        struct mru_entry *p;
1117
1118        prepare_packed_git();
1119        if (!packed_git)
1120                return 0;
1121
1122        for (p = packed_git_mru->head; p; p = p->next) {
1123                if (fill_pack_entry(sha1, e, p->item)) {
1124                        mru_mark(packed_git_mru, p);
1125                        return 1;
1126                }
1127        }
1128        return 0;
1129}
1130
1131static int sha1_loose_object_info(const unsigned char *sha1,
1132                                  struct object_info *oi,
1133                                  int flags)
1134{
1135        int status = 0;
1136        unsigned long mapsize;
1137        void *map;
1138        git_zstream stream;
1139        char hdr[32];
1140        struct strbuf hdrbuf = STRBUF_INIT;
1141        unsigned long size_scratch;
1142
1143        if (oi->delta_base_sha1)
1144                hashclr(oi->delta_base_sha1);
1145
1146        /*
1147         * If we don't care about type or size, then we don't
1148         * need to look inside the object at all. Note that we
1149         * do not optimize out the stat call, even if the
1150         * caller doesn't care about the disk-size, since our
1151         * return value implicitly indicates whether the
1152         * object even exists.
1153         */
1154        if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1155                const char *path;
1156                struct stat st;
1157                if (stat_sha1_file(sha1, &st, &path) < 0)
1158                        return -1;
1159                if (oi->disk_sizep)
1160                        *oi->disk_sizep = st.st_size;
1161                return 0;
1162        }
1163
1164        map = map_sha1_file(sha1, &mapsize);
1165        if (!map)
1166                return -1;
1167
1168        if (!oi->sizep)
1169                oi->sizep = &size_scratch;
1170
1171        if (oi->disk_sizep)
1172                *oi->disk_sizep = mapsize;
1173        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1174                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1175                        status = error("unable to unpack %s header with --allow-unknown-type",
1176                                       sha1_to_hex(sha1));
1177        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1178                status = error("unable to unpack %s header",
1179                               sha1_to_hex(sha1));
1180        if (status < 0)
1181                ; /* Do nothing */
1182        else if (hdrbuf.len) {
1183                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1184                        status = error("unable to parse %s header with --allow-unknown-type",
1185                                       sha1_to_hex(sha1));
1186        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1187                status = error("unable to parse %s header", sha1_to_hex(sha1));
1188
1189        if (status >= 0 && oi->contentp)
1190                *oi->contentp = unpack_sha1_rest(&stream, hdr,
1191                                                 *oi->sizep, sha1);
1192        else
1193                git_inflate_end(&stream);
1194
1195        munmap(map, mapsize);
1196        if (status && oi->typep)
1197                *oi->typep = status;
1198        if (oi->sizep == &size_scratch)
1199                oi->sizep = NULL;
1200        strbuf_release(&hdrbuf);
1201        oi->whence = OI_LOOSE;
1202        return (status < 0) ? status : 0;
1203}
1204
1205int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1206{
1207        static struct object_info blank_oi = OBJECT_INFO_INIT;
1208        struct pack_entry e;
1209        int rtype;
1210        const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1211                                    lookup_replace_object(sha1) :
1212                                    sha1;
1213
1214        if (!oi)
1215                oi = &blank_oi;
1216
1217        if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1218                struct cached_object *co = find_cached_object(real);
1219                if (co) {
1220                        if (oi->typep)
1221                                *(oi->typep) = co->type;
1222                        if (oi->sizep)
1223                                *(oi->sizep) = co->size;
1224                        if (oi->disk_sizep)
1225                                *(oi->disk_sizep) = 0;
1226                        if (oi->delta_base_sha1)
1227                                hashclr(oi->delta_base_sha1);
1228                        if (oi->typename)
1229                                strbuf_addstr(oi->typename, typename(co->type));
1230                        if (oi->contentp)
1231                                *oi->contentp = xmemdupz(co->buf, co->size);
1232                        oi->whence = OI_CACHED;
1233                        return 0;
1234                }
1235        }
1236
1237        if (!find_pack_entry(real, &e)) {
1238                /* Most likely it's a loose object. */
1239                if (!sha1_loose_object_info(real, oi, flags))
1240                        return 0;
1241
1242                /* Not a loose object; someone else may have just packed it. */
1243                if (flags & OBJECT_INFO_QUICK) {
1244                        return -1;
1245                } else {
1246                        reprepare_packed_git();
1247                        if (!find_pack_entry(real, &e))
1248                                return -1;
1249                }
1250        }
1251
1252        if (oi == &blank_oi)
1253                /*
1254                 * We know that the caller doesn't actually need the
1255                 * information below, so return early.
1256                 */
1257                return 0;
1258
1259        rtype = packed_object_info(e.p, e.offset, oi);
1260        if (rtype < 0) {
1261                mark_bad_packed_object(e.p, real);
1262                return sha1_object_info_extended(real, oi, 0);
1263        } else if (oi->whence == OI_PACKED) {
1264                oi->u.packed.offset = e.offset;
1265                oi->u.packed.pack = e.p;
1266                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1267                                         rtype == OBJ_OFS_DELTA);
1268        }
1269
1270        return 0;
1271}
1272
1273/* returns enum object_type or negative */
1274int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1275{
1276        enum object_type type;
1277        struct object_info oi = OBJECT_INFO_INIT;
1278
1279        oi.typep = &type;
1280        oi.sizep = sizep;
1281        if (sha1_object_info_extended(sha1, &oi,
1282                                      OBJECT_INFO_LOOKUP_REPLACE) < 0)
1283                return -1;
1284        return type;
1285}
1286
1287static void *read_object(const unsigned char *sha1, enum object_type *type,
1288                         unsigned long *size)
1289{
1290        struct object_info oi = OBJECT_INFO_INIT;
1291        void *content;
1292        oi.typep = type;
1293        oi.sizep = size;
1294        oi.contentp = &content;
1295
1296        if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1297                return NULL;
1298        return content;
1299}
1300
1301int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1302                      unsigned char *sha1)
1303{
1304        struct cached_object *co;
1305
1306        hash_sha1_file(buf, len, typename(type), sha1);
1307        if (has_sha1_file(sha1) || find_cached_object(sha1))
1308                return 0;
1309        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1310        co = &cached_objects[cached_object_nr++];
1311        co->size = len;
1312        co->type = type;
1313        co->buf = xmalloc(len);
1314        memcpy(co->buf, buf, len);
1315        hashcpy(co->sha1, sha1);
1316        return 0;
1317}
1318
1319/*
1320 * This function dies on corrupt objects; the callers who want to
1321 * deal with them should arrange to call read_object() and give error
1322 * messages themselves.
1323 */
1324void *read_sha1_file_extended(const unsigned char *sha1,
1325                              enum object_type *type,
1326                              unsigned long *size,
1327                              int lookup_replace)
1328{
1329        void *data;
1330        const struct packed_git *p;
1331        const char *path;
1332        struct stat st;
1333        const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1334                                                   : sha1;
1335
1336        errno = 0;
1337        data = read_object(repl, type, size);
1338        if (data)
1339                return data;
1340
1341        if (errno && errno != ENOENT)
1342                die_errno("failed to read object %s", sha1_to_hex(sha1));
1343
1344        /* die if we replaced an object with one that does not exist */
1345        if (repl != sha1)
1346                die("replacement %s not found for %s",
1347                    sha1_to_hex(repl), sha1_to_hex(sha1));
1348
1349        if (!stat_sha1_file(repl, &st, &path))
1350                die("loose object %s (stored in %s) is corrupt",
1351                    sha1_to_hex(repl), path);
1352
1353        if ((p = has_packed_and_bad(repl)) != NULL)
1354                die("packed object %s (stored in %s) is corrupt",
1355                    sha1_to_hex(repl), p->pack_name);
1356
1357        return NULL;
1358}
1359
1360void *read_object_with_reference(const unsigned char *sha1,
1361                                 const char *required_type_name,
1362                                 unsigned long *size,
1363                                 unsigned char *actual_sha1_return)
1364{
1365        enum object_type type, required_type;
1366        void *buffer;
1367        unsigned long isize;
1368        unsigned char actual_sha1[20];
1369
1370        required_type = type_from_string(required_type_name);
1371        hashcpy(actual_sha1, sha1);
1372        while (1) {
1373                int ref_length = -1;
1374                const char *ref_type = NULL;
1375
1376                buffer = read_sha1_file(actual_sha1, &type, &isize);
1377                if (!buffer)
1378                        return NULL;
1379                if (type == required_type) {
1380                        *size = isize;
1381                        if (actual_sha1_return)
1382                                hashcpy(actual_sha1_return, actual_sha1);
1383                        return buffer;
1384                }
1385                /* Handle references */
1386                else if (type == OBJ_COMMIT)
1387                        ref_type = "tree ";
1388                else if (type == OBJ_TAG)
1389                        ref_type = "object ";
1390                else {
1391                        free(buffer);
1392                        return NULL;
1393                }
1394                ref_length = strlen(ref_type);
1395
1396                if (ref_length + 40 > isize ||
1397                    memcmp(buffer, ref_type, ref_length) ||
1398                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1399                        free(buffer);
1400                        return NULL;
1401                }
1402                free(buffer);
1403                /* Now we have the ID of the referred-to object in
1404                 * actual_sha1.  Check again. */
1405        }
1406}
1407
1408static void write_sha1_file_prepare(const void *buf, unsigned long len,
1409                                    const char *type, unsigned char *sha1,
1410                                    char *hdr, int *hdrlen)
1411{
1412        git_SHA_CTX c;
1413
1414        /* Generate the header */
1415        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1416
1417        /* Sha1.. */
1418        git_SHA1_Init(&c);
1419        git_SHA1_Update(&c, hdr, *hdrlen);
1420        git_SHA1_Update(&c, buf, len);
1421        git_SHA1_Final(sha1, &c);
1422}
1423
1424/*
1425 * Move the just written object into its final resting place.
1426 */
1427int finalize_object_file(const char *tmpfile, const char *filename)
1428{
1429        int ret = 0;
1430
1431        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1432                goto try_rename;
1433        else if (link(tmpfile, filename))
1434                ret = errno;
1435
1436        /*
1437         * Coda hack - coda doesn't like cross-directory links,
1438         * so we fall back to a rename, which will mean that it
1439         * won't be able to check collisions, but that's not a
1440         * big deal.
1441         *
1442         * The same holds for FAT formatted media.
1443         *
1444         * When this succeeds, we just return.  We have nothing
1445         * left to unlink.
1446         */
1447        if (ret && ret != EEXIST) {
1448        try_rename:
1449                if (!rename(tmpfile, filename))
1450                        goto out;
1451                ret = errno;
1452        }
1453        unlink_or_warn(tmpfile);
1454        if (ret) {
1455                if (ret != EEXIST) {
1456                        return error_errno("unable to write sha1 filename %s", filename);
1457                }
1458                /* FIXME!!! Collision check here ? */
1459        }
1460
1461out:
1462        if (adjust_shared_perm(filename))
1463                return error("unable to set permission to '%s'", filename);
1464        return 0;
1465}
1466
1467static int write_buffer(int fd, const void *buf, size_t len)
1468{
1469        if (write_in_full(fd, buf, len) < 0)
1470                return error_errno("file write error");
1471        return 0;
1472}
1473
1474int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1475                   unsigned char *sha1)
1476{
1477        char hdr[32];
1478        int hdrlen = sizeof(hdr);
1479        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1480        return 0;
1481}
1482
1483/* Finalize a file on disk, and close it. */
1484static void close_sha1_file(int fd)
1485{
1486        if (fsync_object_files)
1487                fsync_or_die(fd, "sha1 file");
1488        if (close(fd) != 0)
1489                die_errno("error when closing sha1 file");
1490}
1491
1492/* Size of directory component, including the ending '/' */
1493static inline int directory_size(const char *filename)
1494{
1495        const char *s = strrchr(filename, '/');
1496        if (!s)
1497                return 0;
1498        return s - filename + 1;
1499}
1500
1501/*
1502 * This creates a temporary file in the same directory as the final
1503 * 'filename'
1504 *
1505 * We want to avoid cross-directory filename renames, because those
1506 * can have problems on various filesystems (FAT, NFS, Coda).
1507 */
1508static int create_tmpfile(struct strbuf *tmp, const char *filename)
1509{
1510        int fd, dirlen = directory_size(filename);
1511
1512        strbuf_reset(tmp);
1513        strbuf_add(tmp, filename, dirlen);
1514        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1515        fd = git_mkstemp_mode(tmp->buf, 0444);
1516        if (fd < 0 && dirlen && errno == ENOENT) {
1517                /*
1518                 * Make sure the directory exists; note that the contents
1519                 * of the buffer are undefined after mkstemp returns an
1520                 * error, so we have to rewrite the whole buffer from
1521                 * scratch.
1522                 */
1523                strbuf_reset(tmp);
1524                strbuf_add(tmp, filename, dirlen - 1);
1525                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1526                        return -1;
1527                if (adjust_shared_perm(tmp->buf))
1528                        return -1;
1529
1530                /* Try again */
1531                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1532                fd = git_mkstemp_mode(tmp->buf, 0444);
1533        }
1534        return fd;
1535}
1536
1537static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1538                              const void *buf, unsigned long len, time_t mtime)
1539{
1540        int fd, ret;
1541        unsigned char compressed[4096];
1542        git_zstream stream;
1543        git_SHA_CTX c;
1544        unsigned char parano_sha1[20];
1545        static struct strbuf tmp_file = STRBUF_INIT;
1546        const char *filename = sha1_file_name(sha1);
1547
1548        fd = create_tmpfile(&tmp_file, filename);
1549        if (fd < 0) {
1550                if (errno == EACCES)
1551                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1552                else
1553                        return error_errno("unable to create temporary file");
1554        }
1555
1556        /* Set it up */
1557        git_deflate_init(&stream, zlib_compression_level);
1558        stream.next_out = compressed;
1559        stream.avail_out = sizeof(compressed);
1560        git_SHA1_Init(&c);
1561
1562        /* First header.. */
1563        stream.next_in = (unsigned char *)hdr;
1564        stream.avail_in = hdrlen;
1565        while (git_deflate(&stream, 0) == Z_OK)
1566                ; /* nothing */
1567        git_SHA1_Update(&c, hdr, hdrlen);
1568
1569        /* Then the data itself.. */
1570        stream.next_in = (void *)buf;
1571        stream.avail_in = len;
1572        do {
1573                unsigned char *in0 = stream.next_in;
1574                ret = git_deflate(&stream, Z_FINISH);
1575                git_SHA1_Update(&c, in0, stream.next_in - in0);
1576                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1577                        die("unable to write sha1 file");
1578                stream.next_out = compressed;
1579                stream.avail_out = sizeof(compressed);
1580        } while (ret == Z_OK);
1581
1582        if (ret != Z_STREAM_END)
1583                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1584        ret = git_deflate_end_gently(&stream);
1585        if (ret != Z_OK)
1586                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1587        git_SHA1_Final(parano_sha1, &c);
1588        if (hashcmp(sha1, parano_sha1) != 0)
1589                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1590
1591        close_sha1_file(fd);
1592
1593        if (mtime) {
1594                struct utimbuf utb;
1595                utb.actime = mtime;
1596                utb.modtime = mtime;
1597                if (utime(tmp_file.buf, &utb) < 0)
1598                        warning_errno("failed utime() on %s", tmp_file.buf);
1599        }
1600
1601        return finalize_object_file(tmp_file.buf, filename);
1602}
1603
1604static int freshen_loose_object(const unsigned char *sha1)
1605{
1606        return check_and_freshen(sha1, 1);
1607}
1608
1609static int freshen_packed_object(const unsigned char *sha1)
1610{
1611        struct pack_entry e;
1612        if (!find_pack_entry(sha1, &e))
1613                return 0;
1614        if (e.p->freshened)
1615                return 1;
1616        if (!freshen_file(e.p->pack_name))
1617                return 0;
1618        e.p->freshened = 1;
1619        return 1;
1620}
1621
1622int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1623{
1624        char hdr[32];
1625        int hdrlen = sizeof(hdr);
1626
1627        /* Normally if we have it in the pack then we do not bother writing
1628         * it out into .git/objects/??/?{38} file.
1629         */
1630        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1631        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1632                return 0;
1633        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1634}
1635
1636int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1637                             unsigned char *sha1, unsigned flags)
1638{
1639        char *header;
1640        int hdrlen, status = 0;
1641
1642        /* type string, SP, %lu of the length plus NUL must fit this */
1643        hdrlen = strlen(type) + 32;
1644        header = xmalloc(hdrlen);
1645        write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
1646
1647        if (!(flags & HASH_WRITE_OBJECT))
1648                goto cleanup;
1649        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1650                goto cleanup;
1651        status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
1652
1653cleanup:
1654        free(header);
1655        return status;
1656}
1657
1658int force_object_loose(const unsigned char *sha1, time_t mtime)
1659{
1660        void *buf;
1661        unsigned long len;
1662        enum object_type type;
1663        char hdr[32];
1664        int hdrlen;
1665        int ret;
1666
1667        if (has_loose_object(sha1))
1668                return 0;
1669        buf = read_object(sha1, &type, &len);
1670        if (!buf)
1671                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1672        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1673        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1674        free(buf);
1675
1676        return ret;
1677}
1678
1679int has_pack_index(const unsigned char *sha1)
1680{
1681        struct stat st;
1682        if (stat(sha1_pack_index_name(sha1), &st))
1683                return 0;
1684        return 1;
1685}
1686
1687int has_sha1_pack(const unsigned char *sha1)
1688{
1689        struct pack_entry e;
1690        return find_pack_entry(sha1, &e);
1691}
1692
1693int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1694{
1695        if (!startup_info->have_repository)
1696                return 0;
1697        return sha1_object_info_extended(sha1, NULL,
1698                                         flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1699}
1700
1701int has_object_file(const struct object_id *oid)
1702{
1703        return has_sha1_file(oid->hash);
1704}
1705
1706int has_object_file_with_flags(const struct object_id *oid, int flags)
1707{
1708        return has_sha1_file_with_flags(oid->hash, flags);
1709}
1710
1711static void check_tree(const void *buf, size_t size)
1712{
1713        struct tree_desc desc;
1714        struct name_entry entry;
1715
1716        init_tree_desc(&desc, buf, size);
1717        while (tree_entry(&desc, &entry))
1718                /* do nothing
1719                 * tree_entry() will die() on malformed entries */
1720                ;
1721}
1722
1723static void check_commit(const void *buf, size_t size)
1724{
1725        struct commit c;
1726        memset(&c, 0, sizeof(c));
1727        if (parse_commit_buffer(&c, buf, size))
1728                die("corrupt commit");
1729}
1730
1731static void check_tag(const void *buf, size_t size)
1732{
1733        struct tag t;
1734        memset(&t, 0, sizeof(t));
1735        if (parse_tag_buffer(&t, buf, size))
1736                die("corrupt tag");
1737}
1738
1739static int index_mem(unsigned char *sha1, void *buf, size_t size,
1740                     enum object_type type,
1741                     const char *path, unsigned flags)
1742{
1743        int ret, re_allocated = 0;
1744        int write_object = flags & HASH_WRITE_OBJECT;
1745
1746        if (!type)
1747                type = OBJ_BLOB;
1748
1749        /*
1750         * Convert blobs to git internal format
1751         */
1752        if ((type == OBJ_BLOB) && path) {
1753                struct strbuf nbuf = STRBUF_INIT;
1754                if (convert_to_git(&the_index, path, buf, size, &nbuf,
1755                                   write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
1756                        buf = strbuf_detach(&nbuf, &size);
1757                        re_allocated = 1;
1758                }
1759        }
1760        if (flags & HASH_FORMAT_CHECK) {
1761                if (type == OBJ_TREE)
1762                        check_tree(buf, size);
1763                if (type == OBJ_COMMIT)
1764                        check_commit(buf, size);
1765                if (type == OBJ_TAG)
1766                        check_tag(buf, size);
1767        }
1768
1769        if (write_object)
1770                ret = write_sha1_file(buf, size, typename(type), sha1);
1771        else
1772                ret = hash_sha1_file(buf, size, typename(type), sha1);
1773        if (re_allocated)
1774                free(buf);
1775        return ret;
1776}
1777
1778static int index_stream_convert_blob(unsigned char *sha1, int fd,
1779                                     const char *path, unsigned flags)
1780{
1781        int ret;
1782        const int write_object = flags & HASH_WRITE_OBJECT;
1783        struct strbuf sbuf = STRBUF_INIT;
1784
1785        assert(path);
1786        assert(would_convert_to_git_filter_fd(path));
1787
1788        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1789                                 write_object ? safe_crlf : SAFE_CRLF_FALSE);
1790
1791        if (write_object)
1792                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1793                                      sha1);
1794        else
1795                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1796                                     sha1);
1797        strbuf_release(&sbuf);
1798        return ret;
1799}
1800
1801static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
1802                      const char *path, unsigned flags)
1803{
1804        struct strbuf sbuf = STRBUF_INIT;
1805        int ret;
1806
1807        if (strbuf_read(&sbuf, fd, 4096) >= 0)
1808                ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
1809        else
1810                ret = -1;
1811        strbuf_release(&sbuf);
1812        return ret;
1813}
1814
1815#define SMALL_FILE_SIZE (32*1024)
1816
1817static int index_core(unsigned char *sha1, int fd, size_t size,
1818                      enum object_type type, const char *path,
1819                      unsigned flags)
1820{
1821        int ret;
1822
1823        if (!size) {
1824                ret = index_mem(sha1, "", size, type, path, flags);
1825        } else if (size <= SMALL_FILE_SIZE) {
1826                char *buf = xmalloc(size);
1827                if (size == read_in_full(fd, buf, size))
1828                        ret = index_mem(sha1, buf, size, type, path, flags);
1829                else
1830                        ret = error_errno("short read");
1831                free(buf);
1832        } else {
1833                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1834                ret = index_mem(sha1, buf, size, type, path, flags);
1835                munmap(buf, size);
1836        }
1837        return ret;
1838}
1839
1840/*
1841 * This creates one packfile per large blob unless bulk-checkin
1842 * machinery is "plugged".
1843 *
1844 * This also bypasses the usual "convert-to-git" dance, and that is on
1845 * purpose. We could write a streaming version of the converting
1846 * functions and insert that before feeding the data to fast-import
1847 * (or equivalent in-core API described above). However, that is
1848 * somewhat complicated, as we do not know the size of the filter
1849 * result, which we need to know beforehand when writing a git object.
1850 * Since the primary motivation for trying to stream from the working
1851 * tree file and to avoid mmaping it in core is to deal with large
1852 * binary blobs, they generally do not want to get any conversion, and
1853 * callers should avoid this code path when filters are requested.
1854 */
1855static int index_stream(unsigned char *sha1, int fd, size_t size,
1856                        enum object_type type, const char *path,
1857                        unsigned flags)
1858{
1859        return index_bulk_checkin(sha1, fd, size, type, path, flags);
1860}
1861
1862int index_fd(unsigned char *sha1, int fd, struct stat *st,
1863             enum object_type type, const char *path, unsigned flags)
1864{
1865        int ret;
1866
1867        /*
1868         * Call xsize_t() only when needed to avoid potentially unnecessary
1869         * die() for large files.
1870         */
1871        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1872                ret = index_stream_convert_blob(sha1, fd, path, flags);
1873        else if (!S_ISREG(st->st_mode))
1874                ret = index_pipe(sha1, fd, type, path, flags);
1875        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1876                 (path && would_convert_to_git(&the_index, path)))
1877                ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
1878                                 flags);
1879        else
1880                ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
1881                                   flags);
1882        close(fd);
1883        return ret;
1884}
1885
1886int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
1887{
1888        int fd;
1889        struct strbuf sb = STRBUF_INIT;
1890
1891        switch (st->st_mode & S_IFMT) {
1892        case S_IFREG:
1893                fd = open(path, O_RDONLY);
1894                if (fd < 0)
1895                        return error_errno("open(\"%s\")", path);
1896                if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
1897                        return error("%s: failed to insert into database",
1898                                     path);
1899                break;
1900        case S_IFLNK:
1901                if (strbuf_readlink(&sb, path, st->st_size))
1902                        return error_errno("readlink(\"%s\")", path);
1903                if (!(flags & HASH_WRITE_OBJECT))
1904                        hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
1905                else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
1906                        return error("%s: failed to insert into database",
1907                                     path);
1908                strbuf_release(&sb);
1909                break;
1910        case S_IFDIR:
1911                return resolve_gitlink_ref(path, "HEAD", sha1);
1912        default:
1913                return error("%s: unsupported file type", path);
1914        }
1915        return 0;
1916}
1917
1918int read_pack_header(int fd, struct pack_header *header)
1919{
1920        if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
1921                /* "eof before pack header was fully read" */
1922                return PH_ERROR_EOF;
1923
1924        if (header->hdr_signature != htonl(PACK_SIGNATURE))
1925                /* "protocol error (pack signature mismatch detected)" */
1926                return PH_ERROR_PACK_SIGNATURE;
1927        if (!pack_version_ok(header->hdr_version))
1928                /* "protocol error (pack version unsupported)" */
1929                return PH_ERROR_PROTOCOL;
1930        return 0;
1931}
1932
1933void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1934{
1935        enum object_type type = sha1_object_info(sha1, NULL);
1936        if (type < 0)
1937                die("%s is not a valid object", sha1_to_hex(sha1));
1938        if (type != expect)
1939                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1940                    typename(expect));
1941}
1942
1943int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1944                                struct strbuf *path,
1945                                each_loose_object_fn obj_cb,
1946                                each_loose_cruft_fn cruft_cb,
1947                                each_loose_subdir_fn subdir_cb,
1948                                void *data)
1949{
1950        size_t origlen, baselen;
1951        DIR *dir;
1952        struct dirent *de;
1953        int r = 0;
1954
1955        if (subdir_nr > 0xff)
1956                BUG("invalid loose object subdirectory: %x", subdir_nr);
1957
1958        origlen = path->len;
1959        strbuf_complete(path, '/');
1960        strbuf_addf(path, "%02x", subdir_nr);
1961        baselen = path->len;
1962
1963        dir = opendir(path->buf);
1964        if (!dir) {
1965                if (errno != ENOENT)
1966                        r = error_errno("unable to open %s", path->buf);
1967                strbuf_setlen(path, origlen);
1968                return r;
1969        }
1970
1971        while ((de = readdir(dir))) {
1972                if (is_dot_or_dotdot(de->d_name))
1973                        continue;
1974
1975                strbuf_setlen(path, baselen);
1976                strbuf_addf(path, "/%s", de->d_name);
1977
1978                if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
1979                        char hex[GIT_MAX_HEXSZ+1];
1980                        struct object_id oid;
1981
1982                        xsnprintf(hex, sizeof(hex), "%02x%s",
1983                                  subdir_nr, de->d_name);
1984                        if (!get_oid_hex(hex, &oid)) {
1985                                if (obj_cb) {
1986                                        r = obj_cb(&oid, path->buf, data);
1987                                        if (r)
1988                                                break;
1989                                }
1990                                continue;
1991                        }
1992                }
1993
1994                if (cruft_cb) {
1995                        r = cruft_cb(de->d_name, path->buf, data);
1996                        if (r)
1997                                break;
1998                }
1999        }
2000        closedir(dir);
2001
2002        strbuf_setlen(path, baselen);
2003        if (!r && subdir_cb)
2004                r = subdir_cb(subdir_nr, path->buf, data);
2005
2006        strbuf_setlen(path, origlen);
2007
2008        return r;
2009}
2010
2011int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2012                            each_loose_object_fn obj_cb,
2013                            each_loose_cruft_fn cruft_cb,
2014                            each_loose_subdir_fn subdir_cb,
2015                            void *data)
2016{
2017        int r = 0;
2018        int i;
2019
2020        for (i = 0; i < 256; i++) {
2021                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2022                                                subdir_cb, data);
2023                if (r)
2024                        break;
2025        }
2026
2027        return r;
2028}
2029
2030int for_each_loose_file_in_objdir(const char *path,
2031                                  each_loose_object_fn obj_cb,
2032                                  each_loose_cruft_fn cruft_cb,
2033                                  each_loose_subdir_fn subdir_cb,
2034                                  void *data)
2035{
2036        struct strbuf buf = STRBUF_INIT;
2037        int r;
2038
2039        strbuf_addstr(&buf, path);
2040        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2041                                              subdir_cb, data);
2042        strbuf_release(&buf);
2043
2044        return r;
2045}
2046
2047struct loose_alt_odb_data {
2048        each_loose_object_fn *cb;
2049        void *data;
2050};
2051
2052static int loose_from_alt_odb(struct alternate_object_database *alt,
2053                              void *vdata)
2054{
2055        struct loose_alt_odb_data *data = vdata;
2056        struct strbuf buf = STRBUF_INIT;
2057        int r;
2058
2059        strbuf_addstr(&buf, alt->path);
2060        r = for_each_loose_file_in_objdir_buf(&buf,
2061                                              data->cb, NULL, NULL,
2062                                              data->data);
2063        strbuf_release(&buf);
2064        return r;
2065}
2066
2067int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2068{
2069        struct loose_alt_odb_data alt;
2070        int r;
2071
2072        r = for_each_loose_file_in_objdir(get_object_directory(),
2073                                          cb, NULL, NULL, data);
2074        if (r)
2075                return r;
2076
2077        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2078                return 0;
2079
2080        alt.cb = cb;
2081        alt.data = data;
2082        return foreach_alt_odb(loose_from_alt_odb, &alt);
2083}
2084
2085static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
2086{
2087        uint32_t i;
2088        int r = 0;
2089
2090        for (i = 0; i < p->num_objects; i++) {
2091                struct object_id oid;
2092
2093                if (!nth_packed_object_oid(&oid, p, i))
2094                        return error("unable to get sha1 of object %u in %s",
2095                                     i, p->pack_name);
2096
2097                r = cb(&oid, p, i, data);
2098                if (r)
2099                        break;
2100        }
2101        return r;
2102}
2103
2104int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
2105{
2106        struct packed_git *p;
2107        int r = 0;
2108        int pack_errors = 0;
2109
2110        prepare_packed_git();
2111        for (p = packed_git; p; p = p->next) {
2112                if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2113                        continue;
2114                if (open_pack_index(p)) {
2115                        pack_errors = 1;
2116                        continue;
2117                }
2118                r = for_each_object_in_pack(p, cb, data);
2119                if (r)
2120                        break;
2121        }
2122        return r ? r : pack_errors;
2123}
2124
2125static int check_stream_sha1(git_zstream *stream,
2126                             const char *hdr,
2127                             unsigned long size,
2128                             const char *path,
2129                             const unsigned char *expected_sha1)
2130{
2131        git_SHA_CTX c;
2132        unsigned char real_sha1[GIT_MAX_RAWSZ];
2133        unsigned char buf[4096];
2134        unsigned long total_read;
2135        int status = Z_OK;
2136
2137        git_SHA1_Init(&c);
2138        git_SHA1_Update(&c, hdr, stream->total_out);
2139
2140        /*
2141         * We already read some bytes into hdr, but the ones up to the NUL
2142         * do not count against the object's content size.
2143         */
2144        total_read = stream->total_out - strlen(hdr) - 1;
2145
2146        /*
2147         * This size comparison must be "<=" to read the final zlib packets;
2148         * see the comment in unpack_sha1_rest for details.
2149         */
2150        while (total_read <= size &&
2151               (status == Z_OK || status == Z_BUF_ERROR)) {
2152                stream->next_out = buf;
2153                stream->avail_out = sizeof(buf);
2154                if (size - total_read < stream->avail_out)
2155                        stream->avail_out = size - total_read;
2156                status = git_inflate(stream, Z_FINISH);
2157                git_SHA1_Update(&c, buf, stream->next_out - buf);
2158                total_read += stream->next_out - buf;
2159        }
2160        git_inflate_end(stream);
2161
2162        if (status != Z_STREAM_END) {
2163                error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2164                return -1;
2165        }
2166        if (stream->avail_in) {
2167                error("garbage at end of loose object '%s'",
2168                      sha1_to_hex(expected_sha1));
2169                return -1;
2170        }
2171
2172        git_SHA1_Final(real_sha1, &c);
2173        if (hashcmp(expected_sha1, real_sha1)) {
2174                error("sha1 mismatch for %s (expected %s)", path,
2175                      sha1_to_hex(expected_sha1));
2176                return -1;
2177        }
2178
2179        return 0;
2180}
2181
2182int read_loose_object(const char *path,
2183                      const unsigned char *expected_sha1,
2184                      enum object_type *type,
2185                      unsigned long *size,
2186                      void **contents)
2187{
2188        int ret = -1;
2189        void *map = NULL;
2190        unsigned long mapsize;
2191        git_zstream stream;
2192        char hdr[32];
2193
2194        *contents = NULL;
2195
2196        map = map_sha1_file_1(path, NULL, &mapsize);
2197        if (!map) {
2198                error_errno("unable to mmap %s", path);
2199                goto out;
2200        }
2201
2202        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2203                error("unable to unpack header of %s", path);
2204                goto out;
2205        }
2206
2207        *type = parse_sha1_header(hdr, size);
2208        if (*type < 0) {
2209                error("unable to parse header of %s", path);
2210                git_inflate_end(&stream);
2211                goto out;
2212        }
2213
2214        if (*type == OBJ_BLOB) {
2215                if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2216                        goto out;
2217        } else {
2218                *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2219                if (!*contents) {
2220                        error("unable to unpack contents of %s", path);
2221                        git_inflate_end(&stream);
2222                        goto out;
2223                }
2224                if (check_sha1_signature(expected_sha1, *contents,
2225                                         *size, typename(*type))) {
2226                        error("sha1 mismatch for %s (expected %s)", path,
2227                              sha1_to_hex(expected_sha1));
2228                        free(*contents);
2229                        goto out;
2230                }
2231        }
2232
2233        ret = 0; /* everything checks out */
2234
2235out:
2236        if (map)
2237                munmap(map, mapsize);
2238        return ret;
2239}