sha1_file.con commit am: support --quit (65ed8ff)
   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(void *ctx)
  43{
  44        git_SHA1_Init((git_SHA_CTX *)ctx);
  45}
  46
  47static void git_hash_sha1_update(void *ctx, const void *data, size_t len)
  48{
  49        git_SHA1_Update((git_SHA_CTX *)ctx, data, len);
  50}
  51
  52static void git_hash_sha1_final(unsigned char *hash, void *ctx)
  53{
  54        git_SHA1_Final(hash, (git_SHA_CTX *)ctx);
  55}
  56
  57static void git_hash_unknown_init(void *ctx)
  58{
  59        die("trying to init unknown hash");
  60}
  61
  62static void git_hash_unknown_update(void *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, void *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                0,
  79                git_hash_unknown_init,
  80                git_hash_unknown_update,
  81                git_hash_unknown_final,
  82                NULL,
  83                NULL,
  84        },
  85        {
  86                "sha-1",
  87                /* "sha1", big-endian */
  88                0x73686131,
  89                sizeof(git_SHA_CTX),
  90                GIT_SHA1_RAWSZ,
  91                GIT_SHA1_HEXSZ,
  92                git_hash_sha1_init,
  93                git_hash_sha1_update,
  94                git_hash_sha1_final,
  95                &empty_tree_oid,
  96                &empty_blob_oid,
  97        },
  98};
  99
 100/*
 101 * This is meant to hold a *small* number of objects that you would
 102 * want read_sha1_file() to be able to return, but yet you do not want
 103 * to write them into the object store (e.g. a browse-only
 104 * application).
 105 */
 106static struct cached_object {
 107        unsigned char sha1[20];
 108        enum object_type type;
 109        void *buf;
 110        unsigned long size;
 111} *cached_objects;
 112static int cached_object_nr, cached_object_alloc;
 113
 114static struct cached_object empty_tree = {
 115        EMPTY_TREE_SHA1_BIN_LITERAL,
 116        OBJ_TREE,
 117        "",
 118        0
 119};
 120
 121static struct cached_object *find_cached_object(const unsigned char *sha1)
 122{
 123        int i;
 124        struct cached_object *co = cached_objects;
 125
 126        for (i = 0; i < cached_object_nr; i++, co++) {
 127                if (!hashcmp(co->sha1, sha1))
 128                        return co;
 129        }
 130        if (!hashcmp(sha1, empty_tree.sha1))
 131                return &empty_tree;
 132        return NULL;
 133}
 134
 135
 136static int get_conv_flags(unsigned flags)
 137{
 138        if (flags & HASH_RENORMALIZE)
 139                return CONV_EOL_RENORMALIZE;
 140        else if (flags & HASH_WRITE_OBJECT)
 141          return global_conv_flags_eol;
 142        else
 143                return 0;
 144}
 145
 146
 147int mkdir_in_gitdir(const char *path)
 148{
 149        if (mkdir(path, 0777)) {
 150                int saved_errno = errno;
 151                struct stat st;
 152                struct strbuf sb = STRBUF_INIT;
 153
 154                if (errno != EEXIST)
 155                        return -1;
 156                /*
 157                 * Are we looking at a path in a symlinked worktree
 158                 * whose original repository does not yet have it?
 159                 * e.g. .git/rr-cache pointing at its original
 160                 * repository in which the user hasn't performed any
 161                 * conflict resolution yet?
 162                 */
 163                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 164                    strbuf_readlink(&sb, path, st.st_size) ||
 165                    !is_absolute_path(sb.buf) ||
 166                    mkdir(sb.buf, 0777)) {
 167                        strbuf_release(&sb);
 168                        errno = saved_errno;
 169                        return -1;
 170                }
 171                strbuf_release(&sb);
 172        }
 173        return adjust_shared_perm(path);
 174}
 175
 176enum scld_error safe_create_leading_directories(char *path)
 177{
 178        char *next_component = path + offset_1st_component(path);
 179        enum scld_error ret = SCLD_OK;
 180
 181        while (ret == SCLD_OK && next_component) {
 182                struct stat st;
 183                char *slash = next_component, slash_character;
 184
 185                while (*slash && !is_dir_sep(*slash))
 186                        slash++;
 187
 188                if (!*slash)
 189                        break;
 190
 191                next_component = slash + 1;
 192                while (is_dir_sep(*next_component))
 193                        next_component++;
 194                if (!*next_component)
 195                        break;
 196
 197                slash_character = *slash;
 198                *slash = '\0';
 199                if (!stat(path, &st)) {
 200                        /* path exists */
 201                        if (!S_ISDIR(st.st_mode)) {
 202                                errno = ENOTDIR;
 203                                ret = SCLD_EXISTS;
 204                        }
 205                } else if (mkdir(path, 0777)) {
 206                        if (errno == EEXIST &&
 207                            !stat(path, &st) && S_ISDIR(st.st_mode))
 208                                ; /* somebody created it since we checked */
 209                        else if (errno == ENOENT)
 210                                /*
 211                                 * Either mkdir() failed because
 212                                 * somebody just pruned the containing
 213                                 * directory, or stat() failed because
 214                                 * the file that was in our way was
 215                                 * just removed.  Either way, inform
 216                                 * the caller that it might be worth
 217                                 * trying again:
 218                                 */
 219                                ret = SCLD_VANISHED;
 220                        else
 221                                ret = SCLD_FAILED;
 222                } else if (adjust_shared_perm(path)) {
 223                        ret = SCLD_PERMS;
 224                }
 225                *slash = slash_character;
 226        }
 227        return ret;
 228}
 229
 230enum scld_error safe_create_leading_directories_const(const char *path)
 231{
 232        int save_errno;
 233        /* path points to cache entries, so xstrdup before messing with it */
 234        char *buf = xstrdup(path);
 235        enum scld_error result = safe_create_leading_directories(buf);
 236
 237        save_errno = errno;
 238        free(buf);
 239        errno = save_errno;
 240        return result;
 241}
 242
 243int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 244{
 245        /*
 246         * The number of times we will try to remove empty directories
 247         * in the way of path. This is only 1 because if another
 248         * process is racily creating directories that conflict with
 249         * us, we don't want to fight against them.
 250         */
 251        int remove_directories_remaining = 1;
 252
 253        /*
 254         * The number of times that we will try to create the
 255         * directories containing path. We are willing to attempt this
 256         * more than once, because another process could be trying to
 257         * clean up empty directories at the same time as we are
 258         * trying to create them.
 259         */
 260        int create_directories_remaining = 3;
 261
 262        /* A scratch copy of path, filled lazily if we need it: */
 263        struct strbuf path_copy = STRBUF_INIT;
 264
 265        int ret, save_errno;
 266
 267        /* Sanity check: */
 268        assert(*path);
 269
 270retry_fn:
 271        ret = fn(path, cb);
 272        save_errno = errno;
 273        if (!ret)
 274                goto out;
 275
 276        if (errno == EISDIR && remove_directories_remaining-- > 0) {
 277                /*
 278                 * A directory is in the way. Maybe it is empty; try
 279                 * to remove it:
 280                 */
 281                if (!path_copy.len)
 282                        strbuf_addstr(&path_copy, path);
 283
 284                if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 285                        goto retry_fn;
 286        } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 287                /*
 288                 * Maybe the containing directory didn't exist, or
 289                 * maybe it was just deleted by a process that is
 290                 * racing with us to clean up empty directories. Try
 291                 * to create it:
 292                 */
 293                enum scld_error scld_result;
 294
 295                if (!path_copy.len)
 296                        strbuf_addstr(&path_copy, path);
 297
 298                do {
 299                        scld_result = safe_create_leading_directories(path_copy.buf);
 300                        if (scld_result == SCLD_OK)
 301                                goto retry_fn;
 302                } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 303        }
 304
 305out:
 306        strbuf_release(&path_copy);
 307        errno = save_errno;
 308        return ret;
 309}
 310
 311static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 312{
 313        int i;
 314        for (i = 0; i < 20; i++) {
 315                static char hex[] = "0123456789abcdef";
 316                unsigned int val = sha1[i];
 317                strbuf_addch(buf, hex[val >> 4]);
 318                strbuf_addch(buf, hex[val & 0xf]);
 319                if (!i)
 320                        strbuf_addch(buf, '/');
 321        }
 322}
 323
 324void sha1_file_name(struct strbuf *buf, const unsigned char *sha1)
 325{
 326        strbuf_addstr(buf, get_object_directory());
 327        strbuf_addch(buf, '/');
 328        fill_sha1_path(buf, sha1);
 329}
 330
 331struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 332{
 333        strbuf_setlen(&alt->scratch, alt->base_len);
 334        return &alt->scratch;
 335}
 336
 337static const char *alt_sha1_path(struct alternate_object_database *alt,
 338                                 const unsigned char *sha1)
 339{
 340        struct strbuf *buf = alt_scratch_buf(alt);
 341        fill_sha1_path(buf, sha1);
 342        return buf->buf;
 343}
 344
 345struct alternate_object_database *alt_odb_list;
 346static struct alternate_object_database **alt_odb_tail;
 347
 348/*
 349 * Return non-zero iff the path is usable as an alternate object database.
 350 */
 351static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 352{
 353        struct alternate_object_database *alt;
 354
 355        /* Detect cases where alternate disappeared */
 356        if (!is_directory(path->buf)) {
 357                error("object directory %s does not exist; "
 358                      "check .git/objects/info/alternates.",
 359                      path->buf);
 360                return 0;
 361        }
 362
 363        /*
 364         * Prevent the common mistake of listing the same
 365         * thing twice, or object directory itself.
 366         */
 367        for (alt = alt_odb_list; alt; alt = alt->next) {
 368                if (!fspathcmp(path->buf, alt->path))
 369                        return 0;
 370        }
 371        if (!fspathcmp(path->buf, normalized_objdir))
 372                return 0;
 373
 374        return 1;
 375}
 376
 377/*
 378 * Prepare alternate object database registry.
 379 *
 380 * The variable alt_odb_list points at the list of struct
 381 * alternate_object_database.  The elements on this list come from
 382 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 383 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 384 * whose contents is similar to that environment variable but can be
 385 * LF separated.  Its base points at a statically allocated buffer that
 386 * contains "/the/directory/corresponding/to/.git/objects/...", while
 387 * its name points just after the slash at the end of ".git/objects/"
 388 * in the example above, and has enough space to hold 40-byte hex
 389 * SHA1, an extra slash for the first level indirection, and the
 390 * terminating NUL.
 391 */
 392static void read_info_alternates(const char * relative_base, int depth);
 393static int link_alt_odb_entry(const char *entry, const char *relative_base,
 394        int depth, const char *normalized_objdir)
 395{
 396        struct alternate_object_database *ent;
 397        struct strbuf pathbuf = STRBUF_INIT;
 398
 399        if (!is_absolute_path(entry) && relative_base) {
 400                strbuf_realpath(&pathbuf, relative_base, 1);
 401                strbuf_addch(&pathbuf, '/');
 402        }
 403        strbuf_addstr(&pathbuf, entry);
 404
 405        if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 406                error("unable to normalize alternate object path: %s",
 407                      pathbuf.buf);
 408                strbuf_release(&pathbuf);
 409                return -1;
 410        }
 411
 412        /*
 413         * The trailing slash after the directory name is given by
 414         * this function at the end. Remove duplicates.
 415         */
 416        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 417                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 418
 419        if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 420                strbuf_release(&pathbuf);
 421                return -1;
 422        }
 423
 424        ent = alloc_alt_odb(pathbuf.buf);
 425
 426        /* add the alternate entry */
 427        *alt_odb_tail = ent;
 428        alt_odb_tail = &(ent->next);
 429        ent->next = NULL;
 430
 431        /* recursively add alternates */
 432        read_info_alternates(pathbuf.buf, depth + 1);
 433
 434        strbuf_release(&pathbuf);
 435        return 0;
 436}
 437
 438static const char *parse_alt_odb_entry(const char *string,
 439                                       int sep,
 440                                       struct strbuf *out)
 441{
 442        const char *end;
 443
 444        strbuf_reset(out);
 445
 446        if (*string == '#') {
 447                /* comment; consume up to next separator */
 448                end = strchrnul(string, sep);
 449        } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 450                /*
 451                 * quoted path; unquote_c_style has copied the
 452                 * data for us and set "end". Broken quoting (e.g.,
 453                 * an entry that doesn't end with a quote) falls
 454                 * back to the unquoted case below.
 455                 */
 456        } else {
 457                /* normal, unquoted path */
 458                end = strchrnul(string, sep);
 459                strbuf_add(out, string, end - string);
 460        }
 461
 462        if (*end)
 463                end++;
 464        return end;
 465}
 466
 467static void link_alt_odb_entries(const char *alt, int sep,
 468                                 const char *relative_base, int depth)
 469{
 470        struct strbuf objdirbuf = STRBUF_INIT;
 471        struct strbuf entry = STRBUF_INIT;
 472
 473        if (!alt || !*alt)
 474                return;
 475
 476        if (depth > 5) {
 477                error("%s: ignoring alternate object stores, nesting too deep.",
 478                                relative_base);
 479                return;
 480        }
 481
 482        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 483        if (strbuf_normalize_path(&objdirbuf) < 0)
 484                die("unable to normalize object directory: %s",
 485                    objdirbuf.buf);
 486
 487        while (*alt) {
 488                alt = parse_alt_odb_entry(alt, sep, &entry);
 489                if (!entry.len)
 490                        continue;
 491                link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 492        }
 493        strbuf_release(&entry);
 494        strbuf_release(&objdirbuf);
 495}
 496
 497static void read_info_alternates(const char * relative_base, int depth)
 498{
 499        char *path;
 500        struct strbuf buf = STRBUF_INIT;
 501
 502        path = xstrfmt("%s/info/alternates", relative_base);
 503        if (strbuf_read_file(&buf, path, 1024) < 0) {
 504                warn_on_fopen_errors(path);
 505                free(path);
 506                return;
 507        }
 508
 509        link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 510        strbuf_release(&buf);
 511        free(path);
 512}
 513
 514struct alternate_object_database *alloc_alt_odb(const char *dir)
 515{
 516        struct alternate_object_database *ent;
 517
 518        FLEX_ALLOC_STR(ent, path, dir);
 519        strbuf_init(&ent->scratch, 0);
 520        strbuf_addf(&ent->scratch, "%s/", dir);
 521        ent->base_len = ent->scratch.len;
 522
 523        return ent;
 524}
 525
 526void add_to_alternates_file(const char *reference)
 527{
 528        struct lock_file lock = LOCK_INIT;
 529        char *alts = git_pathdup("objects/info/alternates");
 530        FILE *in, *out;
 531        int found = 0;
 532
 533        hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 534        out = fdopen_lock_file(&lock, "w");
 535        if (!out)
 536                die_errno("unable to fdopen alternates lockfile");
 537
 538        in = fopen(alts, "r");
 539        if (in) {
 540                struct strbuf line = STRBUF_INIT;
 541
 542                while (strbuf_getline(&line, in) != EOF) {
 543                        if (!strcmp(reference, line.buf)) {
 544                                found = 1;
 545                                break;
 546                        }
 547                        fprintf_or_die(out, "%s\n", line.buf);
 548                }
 549
 550                strbuf_release(&line);
 551                fclose(in);
 552        }
 553        else if (errno != ENOENT)
 554                die_errno("unable to read alternates file");
 555
 556        if (found) {
 557                rollback_lock_file(&lock);
 558        } else {
 559                fprintf_or_die(out, "%s\n", reference);
 560                if (commit_lock_file(&lock))
 561                        die_errno("unable to move new alternates file into place");
 562                if (alt_odb_tail)
 563                        link_alt_odb_entries(reference, '\n', NULL, 0);
 564        }
 565        free(alts);
 566}
 567
 568void add_to_alternates_memory(const char *reference)
 569{
 570        /*
 571         * Make sure alternates are initialized, or else our entry may be
 572         * overwritten when they are.
 573         */
 574        prepare_alt_odb();
 575
 576        link_alt_odb_entries(reference, '\n', NULL, 0);
 577}
 578
 579/*
 580 * Compute the exact path an alternate is at and returns it. In case of
 581 * error NULL is returned and the human readable error is added to `err`
 582 * `path` may be relative and should point to $GITDIR.
 583 * `err` must not be null.
 584 */
 585char *compute_alternate_path(const char *path, struct strbuf *err)
 586{
 587        char *ref_git = NULL;
 588        const char *repo, *ref_git_s;
 589        int seen_error = 0;
 590
 591        ref_git_s = real_path_if_valid(path);
 592        if (!ref_git_s) {
 593                seen_error = 1;
 594                strbuf_addf(err, _("path '%s' does not exist"), path);
 595                goto out;
 596        } else
 597                /*
 598                 * Beware: read_gitfile(), real_path() and mkpath()
 599                 * return static buffer
 600                 */
 601                ref_git = xstrdup(ref_git_s);
 602
 603        repo = read_gitfile(ref_git);
 604        if (!repo)
 605                repo = read_gitfile(mkpath("%s/.git", ref_git));
 606        if (repo) {
 607                free(ref_git);
 608                ref_git = xstrdup(repo);
 609        }
 610
 611        if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 612                char *ref_git_git = mkpathdup("%s/.git", ref_git);
 613                free(ref_git);
 614                ref_git = ref_git_git;
 615        } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 616                struct strbuf sb = STRBUF_INIT;
 617                seen_error = 1;
 618                if (get_common_dir(&sb, ref_git)) {
 619                        strbuf_addf(err,
 620                                    _("reference repository '%s' as a linked "
 621                                      "checkout is not supported yet."),
 622                                    path);
 623                        goto out;
 624                }
 625
 626                strbuf_addf(err, _("reference repository '%s' is not a "
 627                                        "local repository."), path);
 628                goto out;
 629        }
 630
 631        if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 632                strbuf_addf(err, _("reference repository '%s' is shallow"),
 633                            path);
 634                seen_error = 1;
 635                goto out;
 636        }
 637
 638        if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 639                strbuf_addf(err,
 640                            _("reference repository '%s' is grafted"),
 641                            path);
 642                seen_error = 1;
 643                goto out;
 644        }
 645
 646out:
 647        if (seen_error) {
 648                FREE_AND_NULL(ref_git);
 649        }
 650
 651        return ref_git;
 652}
 653
 654int foreach_alt_odb(alt_odb_fn fn, void *cb)
 655{
 656        struct alternate_object_database *ent;
 657        int r = 0;
 658
 659        prepare_alt_odb();
 660        for (ent = alt_odb_list; ent; ent = ent->next) {
 661                r = fn(ent, cb);
 662                if (r)
 663                        break;
 664        }
 665        return r;
 666}
 667
 668void prepare_alt_odb(void)
 669{
 670        const char *alt;
 671
 672        if (alt_odb_tail)
 673                return;
 674
 675        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 676
 677        alt_odb_tail = &alt_odb_list;
 678        link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
 679
 680        read_info_alternates(get_object_directory(), 0);
 681}
 682
 683/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 684static int freshen_file(const char *fn)
 685{
 686        struct utimbuf t;
 687        t.actime = t.modtime = time(NULL);
 688        return !utime(fn, &t);
 689}
 690
 691/*
 692 * All of the check_and_freshen functions return 1 if the file exists and was
 693 * freshened (if freshening was requested), 0 otherwise. If they return
 694 * 0, you should not assume that it is safe to skip a write of the object (it
 695 * either does not exist on disk, or has a stale mtime and may be subject to
 696 * pruning).
 697 */
 698int check_and_freshen_file(const char *fn, int freshen)
 699{
 700        if (access(fn, F_OK))
 701                return 0;
 702        if (freshen && !freshen_file(fn))
 703                return 0;
 704        return 1;
 705}
 706
 707static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 708{
 709        static struct strbuf buf = STRBUF_INIT;
 710
 711        strbuf_reset(&buf);
 712        sha1_file_name(&buf, sha1);
 713
 714        return check_and_freshen_file(buf.buf, freshen);
 715}
 716
 717static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 718{
 719        struct alternate_object_database *alt;
 720        prepare_alt_odb();
 721        for (alt = alt_odb_list; alt; alt = alt->next) {
 722                const char *path = alt_sha1_path(alt, sha1);
 723                if (check_and_freshen_file(path, freshen))
 724                        return 1;
 725        }
 726        return 0;
 727}
 728
 729static int check_and_freshen(const unsigned char *sha1, int freshen)
 730{
 731        return check_and_freshen_local(sha1, freshen) ||
 732               check_and_freshen_nonlocal(sha1, freshen);
 733}
 734
 735int has_loose_object_nonlocal(const unsigned char *sha1)
 736{
 737        return check_and_freshen_nonlocal(sha1, 0);
 738}
 739
 740static int has_loose_object(const unsigned char *sha1)
 741{
 742        return check_and_freshen(sha1, 0);
 743}
 744
 745static void mmap_limit_check(size_t length)
 746{
 747        static size_t limit = 0;
 748        if (!limit) {
 749                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 750                if (!limit)
 751                        limit = SIZE_MAX;
 752        }
 753        if (length > limit)
 754                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 755                    (uintmax_t)length, (uintmax_t)limit);
 756}
 757
 758void *xmmap_gently(void *start, size_t length,
 759                  int prot, int flags, int fd, off_t offset)
 760{
 761        void *ret;
 762
 763        mmap_limit_check(length);
 764        ret = mmap(start, length, prot, flags, fd, offset);
 765        if (ret == MAP_FAILED) {
 766                if (!length)
 767                        return NULL;
 768                release_pack_memory(length);
 769                ret = mmap(start, length, prot, flags, fd, offset);
 770        }
 771        return ret;
 772}
 773
 774void *xmmap(void *start, size_t length,
 775        int prot, int flags, int fd, off_t offset)
 776{
 777        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 778        if (ret == MAP_FAILED)
 779                die_errno("mmap failed");
 780        return ret;
 781}
 782
 783/*
 784 * With an in-core object data in "map", rehash it to make sure the
 785 * object name actually matches "sha1" to detect object corruption.
 786 * With "map" == NULL, try reading the object named with "sha1" using
 787 * the streaming interface and rehash it to do the same.
 788 */
 789int check_sha1_signature(const unsigned char *sha1, void *map,
 790                         unsigned long size, const char *type)
 791{
 792        unsigned char real_sha1[20];
 793        enum object_type obj_type;
 794        struct git_istream *st;
 795        git_SHA_CTX c;
 796        char hdr[32];
 797        int hdrlen;
 798
 799        if (map) {
 800                hash_sha1_file(map, size, type, real_sha1);
 801                return hashcmp(sha1, real_sha1) ? -1 : 0;
 802        }
 803
 804        st = open_istream(sha1, &obj_type, &size, NULL);
 805        if (!st)
 806                return -1;
 807
 808        /* Generate the header */
 809        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 810
 811        /* Sha1.. */
 812        git_SHA1_Init(&c);
 813        git_SHA1_Update(&c, hdr, hdrlen);
 814        for (;;) {
 815                char buf[1024 * 16];
 816                ssize_t readlen = read_istream(st, buf, sizeof(buf));
 817
 818                if (readlen < 0) {
 819                        close_istream(st);
 820                        return -1;
 821                }
 822                if (!readlen)
 823                        break;
 824                git_SHA1_Update(&c, buf, readlen);
 825        }
 826        git_SHA1_Final(real_sha1, &c);
 827        close_istream(st);
 828        return hashcmp(sha1, real_sha1) ? -1 : 0;
 829}
 830
 831int git_open_cloexec(const char *name, int flags)
 832{
 833        int fd;
 834        static int o_cloexec = O_CLOEXEC;
 835
 836        fd = open(name, flags | o_cloexec);
 837        if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 838                /* Try again w/o O_CLOEXEC: the kernel might not support it */
 839                o_cloexec &= ~O_CLOEXEC;
 840                fd = open(name, flags | o_cloexec);
 841        }
 842
 843#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 844        {
 845                static int fd_cloexec = FD_CLOEXEC;
 846
 847                if (!o_cloexec && 0 <= fd && fd_cloexec) {
 848                        /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 849                        int flags = fcntl(fd, F_GETFD);
 850                        if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 851                                fd_cloexec = 0;
 852                }
 853        }
 854#endif
 855        return fd;
 856}
 857
 858/*
 859 * Find "sha1" as a loose object in the local repository or in an alternate.
 860 * Returns 0 on success, negative on failure.
 861 *
 862 * The "path" out-parameter will give the path of the object we found (if any).
 863 * Note that it may point to static storage and is only valid until another
 864 * call to sha1_file_name(), etc.
 865 */
 866static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 867                          const char **path)
 868{
 869        struct alternate_object_database *alt;
 870        static struct strbuf buf = STRBUF_INIT;
 871
 872        strbuf_reset(&buf);
 873        sha1_file_name(&buf, sha1);
 874        *path = buf.buf;
 875
 876        if (!lstat(*path, st))
 877                return 0;
 878
 879        prepare_alt_odb();
 880        errno = ENOENT;
 881        for (alt = alt_odb_list; alt; alt = alt->next) {
 882                *path = alt_sha1_path(alt, sha1);
 883                if (!lstat(*path, st))
 884                        return 0;
 885        }
 886
 887        return -1;
 888}
 889
 890/*
 891 * Like stat_sha1_file(), but actually open the object and return the
 892 * descriptor. See the caveats on the "path" parameter above.
 893 */
 894static int open_sha1_file(const unsigned char *sha1, const char **path)
 895{
 896        int fd;
 897        struct alternate_object_database *alt;
 898        int most_interesting_errno;
 899        static struct strbuf buf = STRBUF_INIT;
 900
 901        strbuf_reset(&buf);
 902        sha1_file_name(&buf, sha1);
 903        *path = buf.buf;
 904
 905        fd = git_open(*path);
 906        if (fd >= 0)
 907                return fd;
 908        most_interesting_errno = errno;
 909
 910        prepare_alt_odb();
 911        for (alt = alt_odb_list; alt; alt = alt->next) {
 912                *path = alt_sha1_path(alt, sha1);
 913                fd = git_open(*path);
 914                if (fd >= 0)
 915                        return fd;
 916                if (most_interesting_errno == ENOENT)
 917                        most_interesting_errno = errno;
 918        }
 919        errno = most_interesting_errno;
 920        return -1;
 921}
 922
 923/*
 924 * Map the loose object at "path" if it is not NULL, or the path found by
 925 * searching for a loose object named "sha1".
 926 */
 927static void *map_sha1_file_1(const char *path,
 928                             const unsigned char *sha1,
 929                             unsigned long *size)
 930{
 931        void *map;
 932        int fd;
 933
 934        if (path)
 935                fd = git_open(path);
 936        else
 937                fd = open_sha1_file(sha1, &path);
 938        map = NULL;
 939        if (fd >= 0) {
 940                struct stat st;
 941
 942                if (!fstat(fd, &st)) {
 943                        *size = xsize_t(st.st_size);
 944                        if (!*size) {
 945                                /* mmap() is forbidden on empty files */
 946                                error("object file %s is empty", path);
 947                                return NULL;
 948                        }
 949                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 950                }
 951                close(fd);
 952        }
 953        return map;
 954}
 955
 956void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 957{
 958        return map_sha1_file_1(NULL, sha1, size);
 959}
 960
 961static int unpack_sha1_short_header(git_zstream *stream,
 962                                    unsigned char *map, unsigned long mapsize,
 963                                    void *buffer, unsigned long bufsiz)
 964{
 965        /* Get the data stream */
 966        memset(stream, 0, sizeof(*stream));
 967        stream->next_in = map;
 968        stream->avail_in = mapsize;
 969        stream->next_out = buffer;
 970        stream->avail_out = bufsiz;
 971
 972        git_inflate_init(stream);
 973        return git_inflate(stream, 0);
 974}
 975
 976int unpack_sha1_header(git_zstream *stream,
 977                       unsigned char *map, unsigned long mapsize,
 978                       void *buffer, unsigned long bufsiz)
 979{
 980        int status = unpack_sha1_short_header(stream, map, mapsize,
 981                                              buffer, bufsiz);
 982
 983        if (status < Z_OK)
 984                return status;
 985
 986        /* Make sure we have the terminating NUL */
 987        if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 988                return -1;
 989        return 0;
 990}
 991
 992static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 993                                        unsigned long mapsize, void *buffer,
 994                                        unsigned long bufsiz, struct strbuf *header)
 995{
 996        int status;
 997
 998        status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 999        if (status < Z_OK)
1000                return -1;
1001
1002        /*
1003         * Check if entire header is unpacked in the first iteration.
1004         */
1005        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1006                return 0;
1007
1008        /*
1009         * buffer[0..bufsiz] was not large enough.  Copy the partial
1010         * result out to header, and then append the result of further
1011         * reading the stream.
1012         */
1013        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1014        stream->next_out = buffer;
1015        stream->avail_out = bufsiz;
1016
1017        do {
1018                status = git_inflate(stream, 0);
1019                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1020                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1021                        return 0;
1022                stream->next_out = buffer;
1023                stream->avail_out = bufsiz;
1024        } while (status != Z_STREAM_END);
1025        return -1;
1026}
1027
1028static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1029{
1030        int bytes = strlen(buffer) + 1;
1031        unsigned char *buf = xmallocz(size);
1032        unsigned long n;
1033        int status = Z_OK;
1034
1035        n = stream->total_out - bytes;
1036        if (n > size)
1037                n = size;
1038        memcpy(buf, (char *) buffer + bytes, n);
1039        bytes = n;
1040        if (bytes <= size) {
1041                /*
1042                 * The above condition must be (bytes <= size), not
1043                 * (bytes < size).  In other words, even though we
1044                 * expect no more output and set avail_out to zero,
1045                 * the input zlib stream may have bytes that express
1046                 * "this concludes the stream", and we *do* want to
1047                 * eat that input.
1048                 *
1049                 * Otherwise we would not be able to test that we
1050                 * consumed all the input to reach the expected size;
1051                 * we also want to check that zlib tells us that all
1052                 * went well with status == Z_STREAM_END at the end.
1053                 */
1054                stream->next_out = buf + bytes;
1055                stream->avail_out = size - bytes;
1056                while (status == Z_OK)
1057                        status = git_inflate(stream, Z_FINISH);
1058        }
1059        if (status == Z_STREAM_END && !stream->avail_in) {
1060                git_inflate_end(stream);
1061                return buf;
1062        }
1063
1064        if (status < 0)
1065                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1066        else if (stream->avail_in)
1067                error("garbage at end of loose object '%s'",
1068                      sha1_to_hex(sha1));
1069        free(buf);
1070        return NULL;
1071}
1072
1073/*
1074 * We used to just use "sscanf()", but that's actually way
1075 * too permissive for what we want to check. So do an anal
1076 * object header parse by hand.
1077 */
1078static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1079                               unsigned int flags)
1080{
1081        const char *type_buf = hdr;
1082        unsigned long size;
1083        int type, type_len = 0;
1084
1085        /*
1086         * The type can be of any size but is followed by
1087         * a space.
1088         */
1089        for (;;) {
1090                char c = *hdr++;
1091                if (!c)
1092                        return -1;
1093                if (c == ' ')
1094                        break;
1095                type_len++;
1096        }
1097
1098        type = type_from_string_gently(type_buf, type_len, 1);
1099        if (oi->typename)
1100                strbuf_add(oi->typename, type_buf, type_len);
1101        /*
1102         * Set type to 0 if its an unknown object and
1103         * we're obtaining the type using '--allow-unknown-type'
1104         * option.
1105         */
1106        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1107                type = 0;
1108        else if (type < 0)
1109                die("invalid object type");
1110        if (oi->typep)
1111                *oi->typep = type;
1112
1113        /*
1114         * The length must follow immediately, and be in canonical
1115         * decimal format (ie "010" is not valid).
1116         */
1117        size = *hdr++ - '0';
1118        if (size > 9)
1119                return -1;
1120        if (size) {
1121                for (;;) {
1122                        unsigned long c = *hdr - '0';
1123                        if (c > 9)
1124                                break;
1125                        hdr++;
1126                        size = size * 10 + c;
1127                }
1128        }
1129
1130        if (oi->sizep)
1131                *oi->sizep = size;
1132
1133        /*
1134         * The length must be followed by a zero byte
1135         */
1136        return *hdr ? -1 : type;
1137}
1138
1139int parse_sha1_header(const char *hdr, unsigned long *sizep)
1140{
1141        struct object_info oi = OBJECT_INFO_INIT;
1142
1143        oi.sizep = sizep;
1144        return parse_sha1_header_extended(hdr, &oi, 0);
1145}
1146
1147static int sha1_loose_object_info(const unsigned char *sha1,
1148                                  struct object_info *oi,
1149                                  int flags)
1150{
1151        int status = 0;
1152        unsigned long mapsize;
1153        void *map;
1154        git_zstream stream;
1155        char hdr[32];
1156        struct strbuf hdrbuf = STRBUF_INIT;
1157        unsigned long size_scratch;
1158
1159        if (oi->delta_base_sha1)
1160                hashclr(oi->delta_base_sha1);
1161
1162        /*
1163         * If we don't care about type or size, then we don't
1164         * need to look inside the object at all. Note that we
1165         * do not optimize out the stat call, even if the
1166         * caller doesn't care about the disk-size, since our
1167         * return value implicitly indicates whether the
1168         * object even exists.
1169         */
1170        if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1171                const char *path;
1172                struct stat st;
1173                if (stat_sha1_file(sha1, &st, &path) < 0)
1174                        return -1;
1175                if (oi->disk_sizep)
1176                        *oi->disk_sizep = st.st_size;
1177                return 0;
1178        }
1179
1180        map = map_sha1_file(sha1, &mapsize);
1181        if (!map)
1182                return -1;
1183
1184        if (!oi->sizep)
1185                oi->sizep = &size_scratch;
1186
1187        if (oi->disk_sizep)
1188                *oi->disk_sizep = mapsize;
1189        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1190                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1191                        status = error("unable to unpack %s header with --allow-unknown-type",
1192                                       sha1_to_hex(sha1));
1193        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1194                status = error("unable to unpack %s header",
1195                               sha1_to_hex(sha1));
1196        if (status < 0)
1197                ; /* Do nothing */
1198        else if (hdrbuf.len) {
1199                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1200                        status = error("unable to parse %s header with --allow-unknown-type",
1201                                       sha1_to_hex(sha1));
1202        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1203                status = error("unable to parse %s header", sha1_to_hex(sha1));
1204
1205        if (status >= 0 && oi->contentp) {
1206                *oi->contentp = unpack_sha1_rest(&stream, hdr,
1207                                                 *oi->sizep, sha1);
1208                if (!*oi->contentp) {
1209                        git_inflate_end(&stream);
1210                        status = -1;
1211                }
1212        } else
1213                git_inflate_end(&stream);
1214
1215        munmap(map, mapsize);
1216        if (status && oi->typep)
1217                *oi->typep = status;
1218        if (oi->sizep == &size_scratch)
1219                oi->sizep = NULL;
1220        strbuf_release(&hdrbuf);
1221        oi->whence = OI_LOOSE;
1222        return (status < 0) ? status : 0;
1223}
1224
1225int fetch_if_missing = 1;
1226
1227int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1228{
1229        static struct object_info blank_oi = OBJECT_INFO_INIT;
1230        struct pack_entry e;
1231        int rtype;
1232        const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1233                                    lookup_replace_object(sha1) :
1234                                    sha1;
1235        int already_retried = 0;
1236
1237        if (is_null_sha1(real))
1238                return -1;
1239
1240        if (!oi)
1241                oi = &blank_oi;
1242
1243        if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1244                struct cached_object *co = find_cached_object(real);
1245                if (co) {
1246                        if (oi->typep)
1247                                *(oi->typep) = co->type;
1248                        if (oi->sizep)
1249                                *(oi->sizep) = co->size;
1250                        if (oi->disk_sizep)
1251                                *(oi->disk_sizep) = 0;
1252                        if (oi->delta_base_sha1)
1253                                hashclr(oi->delta_base_sha1);
1254                        if (oi->typename)
1255                                strbuf_addstr(oi->typename, typename(co->type));
1256                        if (oi->contentp)
1257                                *oi->contentp = xmemdupz(co->buf, co->size);
1258                        oi->whence = OI_CACHED;
1259                        return 0;
1260                }
1261        }
1262
1263        while (1) {
1264                if (find_pack_entry(real, &e))
1265                        break;
1266
1267                /* Most likely it's a loose object. */
1268                if (!sha1_loose_object_info(real, oi, flags))
1269                        return 0;
1270
1271                /* Not a loose object; someone else may have just packed it. */
1272                reprepare_packed_git();
1273                if (find_pack_entry(real, &e))
1274                        break;
1275
1276                /* Check if it is a missing object */
1277                if (fetch_if_missing && repository_format_partial_clone &&
1278                    !already_retried) {
1279                        /*
1280                         * TODO Investigate haveing fetch_object() return
1281                         * TODO error/success and stopping the music here.
1282                         */
1283                        fetch_object(repository_format_partial_clone, real);
1284                        already_retried = 1;
1285                        continue;
1286                }
1287
1288                return -1;
1289        }
1290
1291        if (oi == &blank_oi)
1292                /*
1293                 * We know that the caller doesn't actually need the
1294                 * information below, so return early.
1295                 */
1296                return 0;
1297        rtype = packed_object_info(e.p, e.offset, oi);
1298        if (rtype < 0) {
1299                mark_bad_packed_object(e.p, real);
1300                return sha1_object_info_extended(real, oi, 0);
1301        } else if (oi->whence == OI_PACKED) {
1302                oi->u.packed.offset = e.offset;
1303                oi->u.packed.pack = e.p;
1304                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1305                                         rtype == OBJ_OFS_DELTA);
1306        }
1307
1308        return 0;
1309}
1310
1311/* returns enum object_type or negative */
1312int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1313{
1314        enum object_type type;
1315        struct object_info oi = OBJECT_INFO_INIT;
1316
1317        oi.typep = &type;
1318        oi.sizep = sizep;
1319        if (sha1_object_info_extended(sha1, &oi,
1320                                      OBJECT_INFO_LOOKUP_REPLACE) < 0)
1321                return -1;
1322        return type;
1323}
1324
1325static void *read_object(const unsigned char *sha1, enum object_type *type,
1326                         unsigned long *size)
1327{
1328        struct object_info oi = OBJECT_INFO_INIT;
1329        void *content;
1330        oi.typep = type;
1331        oi.sizep = size;
1332        oi.contentp = &content;
1333
1334        if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1335                return NULL;
1336        return content;
1337}
1338
1339int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1340                      unsigned char *sha1)
1341{
1342        struct cached_object *co;
1343
1344        hash_sha1_file(buf, len, typename(type), sha1);
1345        if (has_sha1_file(sha1) || find_cached_object(sha1))
1346                return 0;
1347        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1348        co = &cached_objects[cached_object_nr++];
1349        co->size = len;
1350        co->type = type;
1351        co->buf = xmalloc(len);
1352        memcpy(co->buf, buf, len);
1353        hashcpy(co->sha1, sha1);
1354        return 0;
1355}
1356
1357/*
1358 * This function dies on corrupt objects; the callers who want to
1359 * deal with them should arrange to call read_object() and give error
1360 * messages themselves.
1361 */
1362void *read_sha1_file_extended(const unsigned char *sha1,
1363                              enum object_type *type,
1364                              unsigned long *size,
1365                              int lookup_replace)
1366{
1367        void *data;
1368        const struct packed_git *p;
1369        const char *path;
1370        struct stat st;
1371        const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1372                                                   : sha1;
1373
1374        errno = 0;
1375        data = read_object(repl, type, size);
1376        if (data)
1377                return data;
1378
1379        if (errno && errno != ENOENT)
1380                die_errno("failed to read object %s", sha1_to_hex(sha1));
1381
1382        /* die if we replaced an object with one that does not exist */
1383        if (repl != sha1)
1384                die("replacement %s not found for %s",
1385                    sha1_to_hex(repl), sha1_to_hex(sha1));
1386
1387        if (!stat_sha1_file(repl, &st, &path))
1388                die("loose object %s (stored in %s) is corrupt",
1389                    sha1_to_hex(repl), path);
1390
1391        if ((p = has_packed_and_bad(repl)) != NULL)
1392                die("packed object %s (stored in %s) is corrupt",
1393                    sha1_to_hex(repl), p->pack_name);
1394
1395        return NULL;
1396}
1397
1398void *read_object_with_reference(const unsigned char *sha1,
1399                                 const char *required_type_name,
1400                                 unsigned long *size,
1401                                 unsigned char *actual_sha1_return)
1402{
1403        enum object_type type, required_type;
1404        void *buffer;
1405        unsigned long isize;
1406        unsigned char actual_sha1[20];
1407
1408        required_type = type_from_string(required_type_name);
1409        hashcpy(actual_sha1, sha1);
1410        while (1) {
1411                int ref_length = -1;
1412                const char *ref_type = NULL;
1413
1414                buffer = read_sha1_file(actual_sha1, &type, &isize);
1415                if (!buffer)
1416                        return NULL;
1417                if (type == required_type) {
1418                        *size = isize;
1419                        if (actual_sha1_return)
1420                                hashcpy(actual_sha1_return, actual_sha1);
1421                        return buffer;
1422                }
1423                /* Handle references */
1424                else if (type == OBJ_COMMIT)
1425                        ref_type = "tree ";
1426                else if (type == OBJ_TAG)
1427                        ref_type = "object ";
1428                else {
1429                        free(buffer);
1430                        return NULL;
1431                }
1432                ref_length = strlen(ref_type);
1433
1434                if (ref_length + 40 > isize ||
1435                    memcmp(buffer, ref_type, ref_length) ||
1436                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1437                        free(buffer);
1438                        return NULL;
1439                }
1440                free(buffer);
1441                /* Now we have the ID of the referred-to object in
1442                 * actual_sha1.  Check again. */
1443        }
1444}
1445
1446static void write_sha1_file_prepare(const void *buf, unsigned long len,
1447                                    const char *type, unsigned char *sha1,
1448                                    char *hdr, int *hdrlen)
1449{
1450        git_SHA_CTX c;
1451
1452        /* Generate the header */
1453        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1454
1455        /* Sha1.. */
1456        git_SHA1_Init(&c);
1457        git_SHA1_Update(&c, hdr, *hdrlen);
1458        git_SHA1_Update(&c, buf, len);
1459        git_SHA1_Final(sha1, &c);
1460}
1461
1462/*
1463 * Move the just written object into its final resting place.
1464 */
1465int finalize_object_file(const char *tmpfile, const char *filename)
1466{
1467        int ret = 0;
1468
1469        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1470                goto try_rename;
1471        else if (link(tmpfile, filename))
1472                ret = errno;
1473
1474        /*
1475         * Coda hack - coda doesn't like cross-directory links,
1476         * so we fall back to a rename, which will mean that it
1477         * won't be able to check collisions, but that's not a
1478         * big deal.
1479         *
1480         * The same holds for FAT formatted media.
1481         *
1482         * When this succeeds, we just return.  We have nothing
1483         * left to unlink.
1484         */
1485        if (ret && ret != EEXIST) {
1486        try_rename:
1487                if (!rename(tmpfile, filename))
1488                        goto out;
1489                ret = errno;
1490        }
1491        unlink_or_warn(tmpfile);
1492        if (ret) {
1493                if (ret != EEXIST) {
1494                        return error_errno("unable to write sha1 filename %s", filename);
1495                }
1496                /* FIXME!!! Collision check here ? */
1497        }
1498
1499out:
1500        if (adjust_shared_perm(filename))
1501                return error("unable to set permission to '%s'", filename);
1502        return 0;
1503}
1504
1505static int write_buffer(int fd, const void *buf, size_t len)
1506{
1507        if (write_in_full(fd, buf, len) < 0)
1508                return error_errno("file write error");
1509        return 0;
1510}
1511
1512int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1513                   unsigned char *sha1)
1514{
1515        char hdr[32];
1516        int hdrlen = sizeof(hdr);
1517        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1518        return 0;
1519}
1520
1521/* Finalize a file on disk, and close it. */
1522static void close_sha1_file(int fd)
1523{
1524        if (fsync_object_files)
1525                fsync_or_die(fd, "sha1 file");
1526        if (close(fd) != 0)
1527                die_errno("error when closing sha1 file");
1528}
1529
1530/* Size of directory component, including the ending '/' */
1531static inline int directory_size(const char *filename)
1532{
1533        const char *s = strrchr(filename, '/');
1534        if (!s)
1535                return 0;
1536        return s - filename + 1;
1537}
1538
1539/*
1540 * This creates a temporary file in the same directory as the final
1541 * 'filename'
1542 *
1543 * We want to avoid cross-directory filename renames, because those
1544 * can have problems on various filesystems (FAT, NFS, Coda).
1545 */
1546static int create_tmpfile(struct strbuf *tmp, const char *filename)
1547{
1548        int fd, dirlen = directory_size(filename);
1549
1550        strbuf_reset(tmp);
1551        strbuf_add(tmp, filename, dirlen);
1552        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1553        fd = git_mkstemp_mode(tmp->buf, 0444);
1554        if (fd < 0 && dirlen && errno == ENOENT) {
1555                /*
1556                 * Make sure the directory exists; note that the contents
1557                 * of the buffer are undefined after mkstemp returns an
1558                 * error, so we have to rewrite the whole buffer from
1559                 * scratch.
1560                 */
1561                strbuf_reset(tmp);
1562                strbuf_add(tmp, filename, dirlen - 1);
1563                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1564                        return -1;
1565                if (adjust_shared_perm(tmp->buf))
1566                        return -1;
1567
1568                /* Try again */
1569                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1570                fd = git_mkstemp_mode(tmp->buf, 0444);
1571        }
1572        return fd;
1573}
1574
1575static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1576                              const void *buf, unsigned long len, time_t mtime)
1577{
1578        int fd, ret;
1579        unsigned char compressed[4096];
1580        git_zstream stream;
1581        git_SHA_CTX c;
1582        unsigned char parano_sha1[20];
1583        static struct strbuf tmp_file = STRBUF_INIT;
1584        static struct strbuf filename = STRBUF_INIT;
1585
1586        strbuf_reset(&filename);
1587        sha1_file_name(&filename, sha1);
1588
1589        fd = create_tmpfile(&tmp_file, filename.buf);
1590        if (fd < 0) {
1591                if (errno == EACCES)
1592                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1593                else
1594                        return error_errno("unable to create temporary file");
1595        }
1596
1597        /* Set it up */
1598        git_deflate_init(&stream, zlib_compression_level);
1599        stream.next_out = compressed;
1600        stream.avail_out = sizeof(compressed);
1601        git_SHA1_Init(&c);
1602
1603        /* First header.. */
1604        stream.next_in = (unsigned char *)hdr;
1605        stream.avail_in = hdrlen;
1606        while (git_deflate(&stream, 0) == Z_OK)
1607                ; /* nothing */
1608        git_SHA1_Update(&c, hdr, hdrlen);
1609
1610        /* Then the data itself.. */
1611        stream.next_in = (void *)buf;
1612        stream.avail_in = len;
1613        do {
1614                unsigned char *in0 = stream.next_in;
1615                ret = git_deflate(&stream, Z_FINISH);
1616                git_SHA1_Update(&c, in0, stream.next_in - in0);
1617                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1618                        die("unable to write sha1 file");
1619                stream.next_out = compressed;
1620                stream.avail_out = sizeof(compressed);
1621        } while (ret == Z_OK);
1622
1623        if (ret != Z_STREAM_END)
1624                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1625        ret = git_deflate_end_gently(&stream);
1626        if (ret != Z_OK)
1627                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1628        git_SHA1_Final(parano_sha1, &c);
1629        if (hashcmp(sha1, parano_sha1) != 0)
1630                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1631
1632        close_sha1_file(fd);
1633
1634        if (mtime) {
1635                struct utimbuf utb;
1636                utb.actime = mtime;
1637                utb.modtime = mtime;
1638                if (utime(tmp_file.buf, &utb) < 0)
1639                        warning_errno("failed utime() on %s", tmp_file.buf);
1640        }
1641
1642        return finalize_object_file(tmp_file.buf, filename.buf);
1643}
1644
1645static int freshen_loose_object(const unsigned char *sha1)
1646{
1647        return check_and_freshen(sha1, 1);
1648}
1649
1650static int freshen_packed_object(const unsigned char *sha1)
1651{
1652        struct pack_entry e;
1653        if (!find_pack_entry(sha1, &e))
1654                return 0;
1655        if (e.p->freshened)
1656                return 1;
1657        if (!freshen_file(e.p->pack_name))
1658                return 0;
1659        e.p->freshened = 1;
1660        return 1;
1661}
1662
1663int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1664{
1665        char hdr[32];
1666        int hdrlen = sizeof(hdr);
1667
1668        /* Normally if we have it in the pack then we do not bother writing
1669         * it out into .git/objects/??/?{38} file.
1670         */
1671        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1672        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1673                return 0;
1674        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1675}
1676
1677int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1678                             struct object_id *oid, unsigned flags)
1679{
1680        char *header;
1681        int hdrlen, status = 0;
1682
1683        /* type string, SP, %lu of the length plus NUL must fit this */
1684        hdrlen = strlen(type) + 32;
1685        header = xmalloc(hdrlen);
1686        write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1687
1688        if (!(flags & HASH_WRITE_OBJECT))
1689                goto cleanup;
1690        if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1691                goto cleanup;
1692        status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1693
1694cleanup:
1695        free(header);
1696        return status;
1697}
1698
1699int force_object_loose(const unsigned char *sha1, time_t mtime)
1700{
1701        void *buf;
1702        unsigned long len;
1703        enum object_type type;
1704        char hdr[32];
1705        int hdrlen;
1706        int ret;
1707
1708        if (has_loose_object(sha1))
1709                return 0;
1710        buf = read_object(sha1, &type, &len);
1711        if (!buf)
1712                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1713        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1714        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1715        free(buf);
1716
1717        return ret;
1718}
1719
1720int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1721{
1722        if (!startup_info->have_repository)
1723                return 0;
1724        return sha1_object_info_extended(sha1, NULL,
1725                                         flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1726}
1727
1728int has_object_file(const struct object_id *oid)
1729{
1730        return has_sha1_file(oid->hash);
1731}
1732
1733int has_object_file_with_flags(const struct object_id *oid, int flags)
1734{
1735        return has_sha1_file_with_flags(oid->hash, flags);
1736}
1737
1738static void check_tree(const void *buf, size_t size)
1739{
1740        struct tree_desc desc;
1741        struct name_entry entry;
1742
1743        init_tree_desc(&desc, buf, size);
1744        while (tree_entry(&desc, &entry))
1745                /* do nothing
1746                 * tree_entry() will die() on malformed entries */
1747                ;
1748}
1749
1750static void check_commit(const void *buf, size_t size)
1751{
1752        struct commit c;
1753        memset(&c, 0, sizeof(c));
1754        if (parse_commit_buffer(&c, buf, size))
1755                die("corrupt commit");
1756}
1757
1758static void check_tag(const void *buf, size_t size)
1759{
1760        struct tag t;
1761        memset(&t, 0, sizeof(t));
1762        if (parse_tag_buffer(&t, buf, size))
1763                die("corrupt tag");
1764}
1765
1766static int index_mem(struct object_id *oid, void *buf, size_t size,
1767                     enum object_type type,
1768                     const char *path, unsigned flags)
1769{
1770        int ret, re_allocated = 0;
1771        int write_object = flags & HASH_WRITE_OBJECT;
1772
1773        if (!type)
1774                type = OBJ_BLOB;
1775
1776        /*
1777         * Convert blobs to git internal format
1778         */
1779        if ((type == OBJ_BLOB) && path) {
1780                struct strbuf nbuf = STRBUF_INIT;
1781                if (convert_to_git(&the_index, path, buf, size, &nbuf,
1782                                   get_conv_flags(flags))) {
1783                        buf = strbuf_detach(&nbuf, &size);
1784                        re_allocated = 1;
1785                }
1786        }
1787        if (flags & HASH_FORMAT_CHECK) {
1788                if (type == OBJ_TREE)
1789                        check_tree(buf, size);
1790                if (type == OBJ_COMMIT)
1791                        check_commit(buf, size);
1792                if (type == OBJ_TAG)
1793                        check_tag(buf, size);
1794        }
1795
1796        if (write_object)
1797                ret = write_sha1_file(buf, size, typename(type), oid->hash);
1798        else
1799                ret = hash_sha1_file(buf, size, typename(type), oid->hash);
1800        if (re_allocated)
1801                free(buf);
1802        return ret;
1803}
1804
1805static int index_stream_convert_blob(struct object_id *oid, int fd,
1806                                     const char *path, unsigned flags)
1807{
1808        int ret;
1809        const int write_object = flags & HASH_WRITE_OBJECT;
1810        struct strbuf sbuf = STRBUF_INIT;
1811
1812        assert(path);
1813        assert(would_convert_to_git_filter_fd(path));
1814
1815        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1816                                 get_conv_flags(flags));
1817
1818        if (write_object)
1819                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1820                                      oid->hash);
1821        else
1822                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1823                                     oid->hash);
1824        strbuf_release(&sbuf);
1825        return ret;
1826}
1827
1828static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1829                      const char *path, unsigned flags)
1830{
1831        struct strbuf sbuf = STRBUF_INIT;
1832        int ret;
1833
1834        if (strbuf_read(&sbuf, fd, 4096) >= 0)
1835                ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1836        else
1837                ret = -1;
1838        strbuf_release(&sbuf);
1839        return ret;
1840}
1841
1842#define SMALL_FILE_SIZE (32*1024)
1843
1844static int index_core(struct object_id *oid, int fd, size_t size,
1845                      enum object_type type, const char *path,
1846                      unsigned flags)
1847{
1848        int ret;
1849
1850        if (!size) {
1851                ret = index_mem(oid, "", size, type, path, flags);
1852        } else if (size <= SMALL_FILE_SIZE) {
1853                char *buf = xmalloc(size);
1854                ssize_t read_result = read_in_full(fd, buf, size);
1855                if (read_result < 0)
1856                        ret = error_errno("read error while indexing %s",
1857                                          path ? path : "<unknown>");
1858                else if (read_result != size)
1859                        ret = error("short read while indexing %s",
1860                                    path ? path : "<unknown>");
1861                else
1862                        ret = index_mem(oid, buf, size, type, path, flags);
1863                free(buf);
1864        } else {
1865                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1866                ret = index_mem(oid, buf, size, type, path, flags);
1867                munmap(buf, size);
1868        }
1869        return ret;
1870}
1871
1872/*
1873 * This creates one packfile per large blob unless bulk-checkin
1874 * machinery is "plugged".
1875 *
1876 * This also bypasses the usual "convert-to-git" dance, and that is on
1877 * purpose. We could write a streaming version of the converting
1878 * functions and insert that before feeding the data to fast-import
1879 * (or equivalent in-core API described above). However, that is
1880 * somewhat complicated, as we do not know the size of the filter
1881 * result, which we need to know beforehand when writing a git object.
1882 * Since the primary motivation for trying to stream from the working
1883 * tree file and to avoid mmaping it in core is to deal with large
1884 * binary blobs, they generally do not want to get any conversion, and
1885 * callers should avoid this code path when filters are requested.
1886 */
1887static int index_stream(struct object_id *oid, int fd, size_t size,
1888                        enum object_type type, const char *path,
1889                        unsigned flags)
1890{
1891        return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1892}
1893
1894int index_fd(struct object_id *oid, int fd, struct stat *st,
1895             enum object_type type, const char *path, unsigned flags)
1896{
1897        int ret;
1898
1899        /*
1900         * Call xsize_t() only when needed to avoid potentially unnecessary
1901         * die() for large files.
1902         */
1903        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1904                ret = index_stream_convert_blob(oid, fd, path, flags);
1905        else if (!S_ISREG(st->st_mode))
1906                ret = index_pipe(oid, fd, type, path, flags);
1907        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1908                 (path && would_convert_to_git(&the_index, path)))
1909                ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
1910                                 flags);
1911        else
1912                ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1913                                   flags);
1914        close(fd);
1915        return ret;
1916}
1917
1918int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1919{
1920        int fd;
1921        struct strbuf sb = STRBUF_INIT;
1922        int rc = 0;
1923
1924        switch (st->st_mode & S_IFMT) {
1925        case S_IFREG:
1926                fd = open(path, O_RDONLY);
1927                if (fd < 0)
1928                        return error_errno("open(\"%s\")", path);
1929                if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1930                        return error("%s: failed to insert into database",
1931                                     path);
1932                break;
1933        case S_IFLNK:
1934                if (strbuf_readlink(&sb, path, st->st_size))
1935                        return error_errno("readlink(\"%s\")", path);
1936                if (!(flags & HASH_WRITE_OBJECT))
1937                        hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1938                else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1939                        rc = error("%s: failed to insert into database", path);
1940                strbuf_release(&sb);
1941                break;
1942        case S_IFDIR:
1943                return resolve_gitlink_ref(path, "HEAD", oid);
1944        default:
1945                return error("%s: unsupported file type", path);
1946        }
1947        return rc;
1948}
1949
1950int read_pack_header(int fd, struct pack_header *header)
1951{
1952        if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1953                /* "eof before pack header was fully read" */
1954                return PH_ERROR_EOF;
1955
1956        if (header->hdr_signature != htonl(PACK_SIGNATURE))
1957                /* "protocol error (pack signature mismatch detected)" */
1958                return PH_ERROR_PACK_SIGNATURE;
1959        if (!pack_version_ok(header->hdr_version))
1960                /* "protocol error (pack version unsupported)" */
1961                return PH_ERROR_PROTOCOL;
1962        return 0;
1963}
1964
1965void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1966{
1967        enum object_type type = sha1_object_info(sha1, NULL);
1968        if (type < 0)
1969                die("%s is not a valid object", sha1_to_hex(sha1));
1970        if (type != expect)
1971                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1972                    typename(expect));
1973}
1974
1975int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1976                                struct strbuf *path,
1977                                each_loose_object_fn obj_cb,
1978                                each_loose_cruft_fn cruft_cb,
1979                                each_loose_subdir_fn subdir_cb,
1980                                void *data)
1981{
1982        size_t origlen, baselen;
1983        DIR *dir;
1984        struct dirent *de;
1985        int r = 0;
1986        struct object_id oid;
1987
1988        if (subdir_nr > 0xff)
1989                BUG("invalid loose object subdirectory: %x", subdir_nr);
1990
1991        origlen = path->len;
1992        strbuf_complete(path, '/');
1993        strbuf_addf(path, "%02x", subdir_nr);
1994
1995        dir = opendir(path->buf);
1996        if (!dir) {
1997                if (errno != ENOENT)
1998                        r = error_errno("unable to open %s", path->buf);
1999                strbuf_setlen(path, origlen);
2000                return r;
2001        }
2002
2003        oid.hash[0] = subdir_nr;
2004        strbuf_addch(path, '/');
2005        baselen = path->len;
2006
2007        while ((de = readdir(dir))) {
2008                size_t namelen;
2009                if (is_dot_or_dotdot(de->d_name))
2010                        continue;
2011
2012                namelen = strlen(de->d_name);
2013                strbuf_setlen(path, baselen);
2014                strbuf_add(path, de->d_name, namelen);
2015                if (namelen == GIT_SHA1_HEXSZ - 2 &&
2016                    !hex_to_bytes(oid.hash + 1, de->d_name,
2017                                  GIT_SHA1_RAWSZ - 1)) {
2018                        if (obj_cb) {
2019                                r = obj_cb(&oid, path->buf, data);
2020                                if (r)
2021                                        break;
2022                        }
2023                        continue;
2024                }
2025
2026                if (cruft_cb) {
2027                        r = cruft_cb(de->d_name, path->buf, data);
2028                        if (r)
2029                                break;
2030                }
2031        }
2032        closedir(dir);
2033
2034        strbuf_setlen(path, baselen - 1);
2035        if (!r && subdir_cb)
2036                r = subdir_cb(subdir_nr, path->buf, data);
2037
2038        strbuf_setlen(path, origlen);
2039
2040        return r;
2041}
2042
2043int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2044                            each_loose_object_fn obj_cb,
2045                            each_loose_cruft_fn cruft_cb,
2046                            each_loose_subdir_fn subdir_cb,
2047                            void *data)
2048{
2049        int r = 0;
2050        int i;
2051
2052        for (i = 0; i < 256; i++) {
2053                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2054                                                subdir_cb, data);
2055                if (r)
2056                        break;
2057        }
2058
2059        return r;
2060}
2061
2062int for_each_loose_file_in_objdir(const char *path,
2063                                  each_loose_object_fn obj_cb,
2064                                  each_loose_cruft_fn cruft_cb,
2065                                  each_loose_subdir_fn subdir_cb,
2066                                  void *data)
2067{
2068        struct strbuf buf = STRBUF_INIT;
2069        int r;
2070
2071        strbuf_addstr(&buf, path);
2072        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2073                                              subdir_cb, data);
2074        strbuf_release(&buf);
2075
2076        return r;
2077}
2078
2079struct loose_alt_odb_data {
2080        each_loose_object_fn *cb;
2081        void *data;
2082};
2083
2084static int loose_from_alt_odb(struct alternate_object_database *alt,
2085                              void *vdata)
2086{
2087        struct loose_alt_odb_data *data = vdata;
2088        struct strbuf buf = STRBUF_INIT;
2089        int r;
2090
2091        strbuf_addstr(&buf, alt->path);
2092        r = for_each_loose_file_in_objdir_buf(&buf,
2093                                              data->cb, NULL, NULL,
2094                                              data->data);
2095        strbuf_release(&buf);
2096        return r;
2097}
2098
2099int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
2100{
2101        struct loose_alt_odb_data alt;
2102        int r;
2103
2104        r = for_each_loose_file_in_objdir(get_object_directory(),
2105                                          cb, NULL, NULL, data);
2106        if (r)
2107                return r;
2108
2109        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2110                return 0;
2111
2112        alt.cb = cb;
2113        alt.data = data;
2114        return foreach_alt_odb(loose_from_alt_odb, &alt);
2115}
2116
2117static int check_stream_sha1(git_zstream *stream,
2118                             const char *hdr,
2119                             unsigned long size,
2120                             const char *path,
2121                             const unsigned char *expected_sha1)
2122{
2123        git_SHA_CTX c;
2124        unsigned char real_sha1[GIT_MAX_RAWSZ];
2125        unsigned char buf[4096];
2126        unsigned long total_read;
2127        int status = Z_OK;
2128
2129        git_SHA1_Init(&c);
2130        git_SHA1_Update(&c, hdr, stream->total_out);
2131
2132        /*
2133         * We already read some bytes into hdr, but the ones up to the NUL
2134         * do not count against the object's content size.
2135         */
2136        total_read = stream->total_out - strlen(hdr) - 1;
2137
2138        /*
2139         * This size comparison must be "<=" to read the final zlib packets;
2140         * see the comment in unpack_sha1_rest for details.
2141         */
2142        while (total_read <= size &&
2143               (status == Z_OK || status == Z_BUF_ERROR)) {
2144                stream->next_out = buf;
2145                stream->avail_out = sizeof(buf);
2146                if (size - total_read < stream->avail_out)
2147                        stream->avail_out = size - total_read;
2148                status = git_inflate(stream, Z_FINISH);
2149                git_SHA1_Update(&c, buf, stream->next_out - buf);
2150                total_read += stream->next_out - buf;
2151        }
2152        git_inflate_end(stream);
2153
2154        if (status != Z_STREAM_END) {
2155                error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2156                return -1;
2157        }
2158        if (stream->avail_in) {
2159                error("garbage at end of loose object '%s'",
2160                      sha1_to_hex(expected_sha1));
2161                return -1;
2162        }
2163
2164        git_SHA1_Final(real_sha1, &c);
2165        if (hashcmp(expected_sha1, real_sha1)) {
2166                error("sha1 mismatch for %s (expected %s)", path,
2167                      sha1_to_hex(expected_sha1));
2168                return -1;
2169        }
2170
2171        return 0;
2172}
2173
2174int read_loose_object(const char *path,
2175                      const unsigned char *expected_sha1,
2176                      enum object_type *type,
2177                      unsigned long *size,
2178                      void **contents)
2179{
2180        int ret = -1;
2181        void *map = NULL;
2182        unsigned long mapsize;
2183        git_zstream stream;
2184        char hdr[32];
2185
2186        *contents = NULL;
2187
2188        map = map_sha1_file_1(path, NULL, &mapsize);
2189        if (!map) {
2190                error_errno("unable to mmap %s", path);
2191                goto out;
2192        }
2193
2194        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2195                error("unable to unpack header of %s", path);
2196                goto out;
2197        }
2198
2199        *type = parse_sha1_header(hdr, size);
2200        if (*type < 0) {
2201                error("unable to parse header of %s", path);
2202                git_inflate_end(&stream);
2203                goto out;
2204        }
2205
2206        if (*type == OBJ_BLOB) {
2207                if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2208                        goto out;
2209        } else {
2210                *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2211                if (!*contents) {
2212                        error("unable to unpack contents of %s", path);
2213                        git_inflate_end(&stream);
2214                        goto out;
2215                }
2216                if (check_sha1_signature(expected_sha1, *contents,
2217                                         *size, typename(*type))) {
2218                        error("sha1 mismatch for %s (expected %s)", path,
2219                              sha1_to_hex(expected_sha1));
2220                        free(*contents);
2221                        goto out;
2222                }
2223        }
2224
2225        ret = 0; /* everything checks out */
2226
2227out:
2228        if (map)
2229                munmap(map, mapsize);
2230        return ret;
2231}