sha1-file.con commit Add a base implementation of SHA-256 support (13eeedb)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This handles basic git sha1 object files - packing, unpacking,
   7 * creation etc.
   8 */
   9#include "cache.h"
  10#include "config.h"
  11#include "string-list.h"
  12#include "lockfile.h"
  13#include "delta.h"
  14#include "pack.h"
  15#include "blob.h"
  16#include "commit.h"
  17#include "run-command.h"
  18#include "tag.h"
  19#include "tree.h"
  20#include "tree-walk.h"
  21#include "refs.h"
  22#include "pack-revindex.h"
  23#include "sha1-lookup.h"
  24#include "bulk-checkin.h"
  25#include "repository.h"
  26#include "replace-object.h"
  27#include "streaming.h"
  28#include "dir.h"
  29#include "list.h"
  30#include "mergesort.h"
  31#include "quote.h"
  32#include "packfile.h"
  33#include "fetch-object.h"
  34#include "object-store.h"
  35
  36/* The maximum size for an object header. */
  37#define MAX_HEADER_LEN 32
  38
  39
  40#define EMPTY_TREE_SHA1_BIN_LITERAL \
  41         "\x4b\x82\x5d\xc6\x42\xcb\x6e\xb9\xa0\x60" \
  42         "\xe5\x4b\xf8\xd6\x92\x88\xfb\xee\x49\x04"
  43#define EMPTY_TREE_SHA256_BIN_LITERAL \
  44        "\x6e\xf1\x9b\x41\x22\x5c\x53\x69\xf1\xc1" \
  45        "\x04\xd4\x5d\x8d\x85\xef\xa9\xb0\x57\xb5" \
  46        "\x3b\x14\xb4\xb9\xb9\x39\xdd\x74\xde\xcc" \
  47        "\x53\x21"
  48
  49#define EMPTY_BLOB_SHA1_BIN_LITERAL \
  50        "\xe6\x9d\xe2\x9b\xb2\xd1\xd6\x43\x4b\x8b" \
  51        "\x29\xae\x77\x5a\xd8\xc2\xe4\x8c\x53\x91"
  52#define EMPTY_BLOB_SHA256_BIN_LITERAL \
  53        "\x47\x3a\x0f\x4c\x3b\xe8\xa9\x36\x81\xa2" \
  54        "\x67\xe3\xb1\xe9\xa7\xdc\xda\x11\x85\x43" \
  55        "\x6f\xe1\x41\xf7\x74\x91\x20\xa3\x03\x72" \
  56        "\x18\x13"
  57
  58const unsigned char null_sha1[GIT_MAX_RAWSZ];
  59const struct object_id null_oid;
  60static const struct object_id empty_tree_oid = {
  61        EMPTY_TREE_SHA1_BIN_LITERAL
  62};
  63static const struct object_id empty_blob_oid = {
  64        EMPTY_BLOB_SHA1_BIN_LITERAL
  65};
  66static const struct object_id empty_tree_oid_sha256 = {
  67        EMPTY_TREE_SHA256_BIN_LITERAL
  68};
  69static const struct object_id empty_blob_oid_sha256 = {
  70        EMPTY_BLOB_SHA256_BIN_LITERAL
  71};
  72
  73static void git_hash_sha1_init(git_hash_ctx *ctx)
  74{
  75        git_SHA1_Init(&ctx->sha1);
  76}
  77
  78static void git_hash_sha1_update(git_hash_ctx *ctx, const void *data, size_t len)
  79{
  80        git_SHA1_Update(&ctx->sha1, data, len);
  81}
  82
  83static void git_hash_sha1_final(unsigned char *hash, git_hash_ctx *ctx)
  84{
  85        git_SHA1_Final(hash, &ctx->sha1);
  86}
  87
  88
  89static void git_hash_sha256_init(git_hash_ctx *ctx)
  90{
  91        git_SHA256_Init(&ctx->sha256);
  92}
  93
  94static void git_hash_sha256_update(git_hash_ctx *ctx, const void *data, size_t len)
  95{
  96        git_SHA256_Update(&ctx->sha256, data, len);
  97}
  98
  99static void git_hash_sha256_final(unsigned char *hash, git_hash_ctx *ctx)
 100{
 101        git_SHA256_Final(hash, &ctx->sha256);
 102}
 103
 104static void git_hash_unknown_init(git_hash_ctx *ctx)
 105{
 106        BUG("trying to init unknown hash");
 107}
 108
 109static void git_hash_unknown_update(git_hash_ctx *ctx, const void *data, size_t len)
 110{
 111        BUG("trying to update unknown hash");
 112}
 113
 114static void git_hash_unknown_final(unsigned char *hash, git_hash_ctx *ctx)
 115{
 116        BUG("trying to finalize unknown hash");
 117}
 118
 119const struct git_hash_algo hash_algos[GIT_HASH_NALGOS] = {
 120        {
 121                NULL,
 122                0x00000000,
 123                0,
 124                0,
 125                0,
 126                git_hash_unknown_init,
 127                git_hash_unknown_update,
 128                git_hash_unknown_final,
 129                NULL,
 130                NULL,
 131        },
 132        {
 133                "sha1",
 134                /* "sha1", big-endian */
 135                0x73686131,
 136                GIT_SHA1_RAWSZ,
 137                GIT_SHA1_HEXSZ,
 138                GIT_SHA1_BLKSZ,
 139                git_hash_sha1_init,
 140                git_hash_sha1_update,
 141                git_hash_sha1_final,
 142                &empty_tree_oid,
 143                &empty_blob_oid,
 144        },
 145        {
 146                "sha256",
 147                /* "s256", big-endian */
 148                0x73323536,
 149                GIT_SHA256_RAWSZ,
 150                GIT_SHA256_HEXSZ,
 151                GIT_SHA256_BLKSZ,
 152                git_hash_sha256_init,
 153                git_hash_sha256_update,
 154                git_hash_sha256_final,
 155                &empty_tree_oid_sha256,
 156                &empty_blob_oid_sha256,
 157        }
 158};
 159
 160const char *empty_tree_oid_hex(void)
 161{
 162        static char buf[GIT_MAX_HEXSZ + 1];
 163        return oid_to_hex_r(buf, the_hash_algo->empty_tree);
 164}
 165
 166const char *empty_blob_oid_hex(void)
 167{
 168        static char buf[GIT_MAX_HEXSZ + 1];
 169        return oid_to_hex_r(buf, the_hash_algo->empty_blob);
 170}
 171
 172int hash_algo_by_name(const char *name)
 173{
 174        int i;
 175        if (!name)
 176                return GIT_HASH_UNKNOWN;
 177        for (i = 1; i < GIT_HASH_NALGOS; i++)
 178                if (!strcmp(name, hash_algos[i].name))
 179                        return i;
 180        return GIT_HASH_UNKNOWN;
 181}
 182
 183int hash_algo_by_id(uint32_t format_id)
 184{
 185        int i;
 186        for (i = 1; i < GIT_HASH_NALGOS; i++)
 187                if (format_id == hash_algos[i].format_id)
 188                        return i;
 189        return GIT_HASH_UNKNOWN;
 190}
 191
 192
 193/*
 194 * This is meant to hold a *small* number of objects that you would
 195 * want read_sha1_file() to be able to return, but yet you do not want
 196 * to write them into the object store (e.g. a browse-only
 197 * application).
 198 */
 199static struct cached_object {
 200        struct object_id oid;
 201        enum object_type type;
 202        void *buf;
 203        unsigned long size;
 204} *cached_objects;
 205static int cached_object_nr, cached_object_alloc;
 206
 207static struct cached_object empty_tree = {
 208        { EMPTY_TREE_SHA1_BIN_LITERAL },
 209        OBJ_TREE,
 210        "",
 211        0
 212};
 213
 214static struct cached_object *find_cached_object(const struct object_id *oid)
 215{
 216        int i;
 217        struct cached_object *co = cached_objects;
 218
 219        for (i = 0; i < cached_object_nr; i++, co++) {
 220                if (oideq(&co->oid, oid))
 221                        return co;
 222        }
 223        if (oideq(oid, the_hash_algo->empty_tree))
 224                return &empty_tree;
 225        return NULL;
 226}
 227
 228
 229static int get_conv_flags(unsigned flags)
 230{
 231        if (flags & HASH_RENORMALIZE)
 232                return CONV_EOL_RENORMALIZE;
 233        else if (flags & HASH_WRITE_OBJECT)
 234                return global_conv_flags_eol | CONV_WRITE_OBJECT;
 235        else
 236                return 0;
 237}
 238
 239
 240int mkdir_in_gitdir(const char *path)
 241{
 242        if (mkdir(path, 0777)) {
 243                int saved_errno = errno;
 244                struct stat st;
 245                struct strbuf sb = STRBUF_INIT;
 246
 247                if (errno != EEXIST)
 248                        return -1;
 249                /*
 250                 * Are we looking at a path in a symlinked worktree
 251                 * whose original repository does not yet have it?
 252                 * e.g. .git/rr-cache pointing at its original
 253                 * repository in which the user hasn't performed any
 254                 * conflict resolution yet?
 255                 */
 256                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 257                    strbuf_readlink(&sb, path, st.st_size) ||
 258                    !is_absolute_path(sb.buf) ||
 259                    mkdir(sb.buf, 0777)) {
 260                        strbuf_release(&sb);
 261                        errno = saved_errno;
 262                        return -1;
 263                }
 264                strbuf_release(&sb);
 265        }
 266        return adjust_shared_perm(path);
 267}
 268
 269enum scld_error safe_create_leading_directories(char *path)
 270{
 271        char *next_component = path + offset_1st_component(path);
 272        enum scld_error ret = SCLD_OK;
 273
 274        while (ret == SCLD_OK && next_component) {
 275                struct stat st;
 276                char *slash = next_component, slash_character;
 277
 278                while (*slash && !is_dir_sep(*slash))
 279                        slash++;
 280
 281                if (!*slash)
 282                        break;
 283
 284                next_component = slash + 1;
 285                while (is_dir_sep(*next_component))
 286                        next_component++;
 287                if (!*next_component)
 288                        break;
 289
 290                slash_character = *slash;
 291                *slash = '\0';
 292                if (!stat(path, &st)) {
 293                        /* path exists */
 294                        if (!S_ISDIR(st.st_mode)) {
 295                                errno = ENOTDIR;
 296                                ret = SCLD_EXISTS;
 297                        }
 298                } else if (mkdir(path, 0777)) {
 299                        if (errno == EEXIST &&
 300                            !stat(path, &st) && S_ISDIR(st.st_mode))
 301                                ; /* somebody created it since we checked */
 302                        else if (errno == ENOENT)
 303                                /*
 304                                 * Either mkdir() failed because
 305                                 * somebody just pruned the containing
 306                                 * directory, or stat() failed because
 307                                 * the file that was in our way was
 308                                 * just removed.  Either way, inform
 309                                 * the caller that it might be worth
 310                                 * trying again:
 311                                 */
 312                                ret = SCLD_VANISHED;
 313                        else
 314                                ret = SCLD_FAILED;
 315                } else if (adjust_shared_perm(path)) {
 316                        ret = SCLD_PERMS;
 317                }
 318                *slash = slash_character;
 319        }
 320        return ret;
 321}
 322
 323enum scld_error safe_create_leading_directories_const(const char *path)
 324{
 325        int save_errno;
 326        /* path points to cache entries, so xstrdup before messing with it */
 327        char *buf = xstrdup(path);
 328        enum scld_error result = safe_create_leading_directories(buf);
 329
 330        save_errno = errno;
 331        free(buf);
 332        errno = save_errno;
 333        return result;
 334}
 335
 336int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 337{
 338        /*
 339         * The number of times we will try to remove empty directories
 340         * in the way of path. This is only 1 because if another
 341         * process is racily creating directories that conflict with
 342         * us, we don't want to fight against them.
 343         */
 344        int remove_directories_remaining = 1;
 345
 346        /*
 347         * The number of times that we will try to create the
 348         * directories containing path. We are willing to attempt this
 349         * more than once, because another process could be trying to
 350         * clean up empty directories at the same time as we are
 351         * trying to create them.
 352         */
 353        int create_directories_remaining = 3;
 354
 355        /* A scratch copy of path, filled lazily if we need it: */
 356        struct strbuf path_copy = STRBUF_INIT;
 357
 358        int ret, save_errno;
 359
 360        /* Sanity check: */
 361        assert(*path);
 362
 363retry_fn:
 364        ret = fn(path, cb);
 365        save_errno = errno;
 366        if (!ret)
 367                goto out;
 368
 369        if (errno == EISDIR && remove_directories_remaining-- > 0) {
 370                /*
 371                 * A directory is in the way. Maybe it is empty; try
 372                 * to remove it:
 373                 */
 374                if (!path_copy.len)
 375                        strbuf_addstr(&path_copy, path);
 376
 377                if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 378                        goto retry_fn;
 379        } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 380                /*
 381                 * Maybe the containing directory didn't exist, or
 382                 * maybe it was just deleted by a process that is
 383                 * racing with us to clean up empty directories. Try
 384                 * to create it:
 385                 */
 386                enum scld_error scld_result;
 387
 388                if (!path_copy.len)
 389                        strbuf_addstr(&path_copy, path);
 390
 391                do {
 392                        scld_result = safe_create_leading_directories(path_copy.buf);
 393                        if (scld_result == SCLD_OK)
 394                                goto retry_fn;
 395                } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 396        }
 397
 398out:
 399        strbuf_release(&path_copy);
 400        errno = save_errno;
 401        return ret;
 402}
 403
 404static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 405{
 406        int i;
 407        for (i = 0; i < the_hash_algo->rawsz; i++) {
 408                static char hex[] = "0123456789abcdef";
 409                unsigned int val = sha1[i];
 410                strbuf_addch(buf, hex[val >> 4]);
 411                strbuf_addch(buf, hex[val & 0xf]);
 412                if (!i)
 413                        strbuf_addch(buf, '/');
 414        }
 415}
 416
 417void sha1_file_name(struct repository *r, struct strbuf *buf, const unsigned char *sha1)
 418{
 419        strbuf_addstr(buf, r->objects->objectdir);
 420        strbuf_addch(buf, '/');
 421        fill_sha1_path(buf, sha1);
 422}
 423
 424struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 425{
 426        strbuf_setlen(&alt->scratch, alt->base_len);
 427        return &alt->scratch;
 428}
 429
 430static const char *alt_sha1_path(struct alternate_object_database *alt,
 431                                 const unsigned char *sha1)
 432{
 433        struct strbuf *buf = alt_scratch_buf(alt);
 434        fill_sha1_path(buf, sha1);
 435        return buf->buf;
 436}
 437
 438/*
 439 * Return non-zero iff the path is usable as an alternate object database.
 440 */
 441static int alt_odb_usable(struct raw_object_store *o,
 442                          struct strbuf *path,
 443                          const char *normalized_objdir)
 444{
 445        struct alternate_object_database *alt;
 446
 447        /* Detect cases where alternate disappeared */
 448        if (!is_directory(path->buf)) {
 449                error(_("object directory %s does not exist; "
 450                        "check .git/objects/info/alternates"),
 451                      path->buf);
 452                return 0;
 453        }
 454
 455        /*
 456         * Prevent the common mistake of listing the same
 457         * thing twice, or object directory itself.
 458         */
 459        for (alt = o->alt_odb_list; alt; alt = alt->next) {
 460                if (!fspathcmp(path->buf, alt->path))
 461                        return 0;
 462        }
 463        if (!fspathcmp(path->buf, normalized_objdir))
 464                return 0;
 465
 466        return 1;
 467}
 468
 469/*
 470 * Prepare alternate object database registry.
 471 *
 472 * The variable alt_odb_list points at the list of struct
 473 * alternate_object_database.  The elements on this list come from
 474 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 475 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 476 * whose contents is similar to that environment variable but can be
 477 * LF separated.  Its base points at a statically allocated buffer that
 478 * contains "/the/directory/corresponding/to/.git/objects/...", while
 479 * its name points just after the slash at the end of ".git/objects/"
 480 * in the example above, and has enough space to hold 40-byte hex
 481 * SHA1, an extra slash for the first level indirection, and the
 482 * terminating NUL.
 483 */
 484static void read_info_alternates(struct repository *r,
 485                                 const char *relative_base,
 486                                 int depth);
 487static int link_alt_odb_entry(struct repository *r, const char *entry,
 488        const char *relative_base, int depth, const char *normalized_objdir)
 489{
 490        struct alternate_object_database *ent;
 491        struct strbuf pathbuf = STRBUF_INIT;
 492
 493        if (!is_absolute_path(entry) && relative_base) {
 494                strbuf_realpath(&pathbuf, relative_base, 1);
 495                strbuf_addch(&pathbuf, '/');
 496        }
 497        strbuf_addstr(&pathbuf, entry);
 498
 499        if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 500                error(_("unable to normalize alternate object path: %s"),
 501                      pathbuf.buf);
 502                strbuf_release(&pathbuf);
 503                return -1;
 504        }
 505
 506        /*
 507         * The trailing slash after the directory name is given by
 508         * this function at the end. Remove duplicates.
 509         */
 510        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 511                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 512
 513        if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir)) {
 514                strbuf_release(&pathbuf);
 515                return -1;
 516        }
 517
 518        ent = alloc_alt_odb(pathbuf.buf);
 519
 520        /* add the alternate entry */
 521        *r->objects->alt_odb_tail = ent;
 522        r->objects->alt_odb_tail = &(ent->next);
 523        ent->next = NULL;
 524
 525        /* recursively add alternates */
 526        read_info_alternates(r, pathbuf.buf, depth + 1);
 527
 528        strbuf_release(&pathbuf);
 529        return 0;
 530}
 531
 532static const char *parse_alt_odb_entry(const char *string,
 533                                       int sep,
 534                                       struct strbuf *out)
 535{
 536        const char *end;
 537
 538        strbuf_reset(out);
 539
 540        if (*string == '#') {
 541                /* comment; consume up to next separator */
 542                end = strchrnul(string, sep);
 543        } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 544                /*
 545                 * quoted path; unquote_c_style has copied the
 546                 * data for us and set "end". Broken quoting (e.g.,
 547                 * an entry that doesn't end with a quote) falls
 548                 * back to the unquoted case below.
 549                 */
 550        } else {
 551                /* normal, unquoted path */
 552                end = strchrnul(string, sep);
 553                strbuf_add(out, string, end - string);
 554        }
 555
 556        if (*end)
 557                end++;
 558        return end;
 559}
 560
 561static void link_alt_odb_entries(struct repository *r, const char *alt,
 562                                 int sep, const char *relative_base, int depth)
 563{
 564        struct strbuf objdirbuf = STRBUF_INIT;
 565        struct strbuf entry = STRBUF_INIT;
 566
 567        if (!alt || !*alt)
 568                return;
 569
 570        if (depth > 5) {
 571                error(_("%s: ignoring alternate object stores, nesting too deep"),
 572                                relative_base);
 573                return;
 574        }
 575
 576        strbuf_add_absolute_path(&objdirbuf, r->objects->objectdir);
 577        if (strbuf_normalize_path(&objdirbuf) < 0)
 578                die(_("unable to normalize object directory: %s"),
 579                    objdirbuf.buf);
 580
 581        while (*alt) {
 582                alt = parse_alt_odb_entry(alt, sep, &entry);
 583                if (!entry.len)
 584                        continue;
 585                link_alt_odb_entry(r, entry.buf,
 586                                   relative_base, depth, objdirbuf.buf);
 587        }
 588        strbuf_release(&entry);
 589        strbuf_release(&objdirbuf);
 590}
 591
 592static void read_info_alternates(struct repository *r,
 593                                 const char *relative_base,
 594                                 int depth)
 595{
 596        char *path;
 597        struct strbuf buf = STRBUF_INIT;
 598
 599        path = xstrfmt("%s/info/alternates", relative_base);
 600        if (strbuf_read_file(&buf, path, 1024) < 0) {
 601                warn_on_fopen_errors(path);
 602                free(path);
 603                return;
 604        }
 605
 606        link_alt_odb_entries(r, buf.buf, '\n', relative_base, depth);
 607        strbuf_release(&buf);
 608        free(path);
 609}
 610
 611struct alternate_object_database *alloc_alt_odb(const char *dir)
 612{
 613        struct alternate_object_database *ent;
 614
 615        FLEX_ALLOC_STR(ent, path, dir);
 616        strbuf_init(&ent->scratch, 0);
 617        strbuf_addf(&ent->scratch, "%s/", dir);
 618        ent->base_len = ent->scratch.len;
 619
 620        return ent;
 621}
 622
 623void add_to_alternates_file(const char *reference)
 624{
 625        struct lock_file lock = LOCK_INIT;
 626        char *alts = git_pathdup("objects/info/alternates");
 627        FILE *in, *out;
 628        int found = 0;
 629
 630        hold_lock_file_for_update(&lock, alts, LOCK_DIE_ON_ERROR);
 631        out = fdopen_lock_file(&lock, "w");
 632        if (!out)
 633                die_errno(_("unable to fdopen alternates lockfile"));
 634
 635        in = fopen(alts, "r");
 636        if (in) {
 637                struct strbuf line = STRBUF_INIT;
 638
 639                while (strbuf_getline(&line, in) != EOF) {
 640                        if (!strcmp(reference, line.buf)) {
 641                                found = 1;
 642                                break;
 643                        }
 644                        fprintf_or_die(out, "%s\n", line.buf);
 645                }
 646
 647                strbuf_release(&line);
 648                fclose(in);
 649        }
 650        else if (errno != ENOENT)
 651                die_errno(_("unable to read alternates file"));
 652
 653        if (found) {
 654                rollback_lock_file(&lock);
 655        } else {
 656                fprintf_or_die(out, "%s\n", reference);
 657                if (commit_lock_file(&lock))
 658                        die_errno(_("unable to move new alternates file into place"));
 659                if (the_repository->objects->alt_odb_tail)
 660                        link_alt_odb_entries(the_repository, reference,
 661                                             '\n', NULL, 0);
 662        }
 663        free(alts);
 664}
 665
 666void add_to_alternates_memory(const char *reference)
 667{
 668        /*
 669         * Make sure alternates are initialized, or else our entry may be
 670         * overwritten when they are.
 671         */
 672        prepare_alt_odb(the_repository);
 673
 674        link_alt_odb_entries(the_repository, reference,
 675                             '\n', NULL, 0);
 676}
 677
 678/*
 679 * Compute the exact path an alternate is at and returns it. In case of
 680 * error NULL is returned and the human readable error is added to `err`
 681 * `path` may be relative and should point to $GIT_DIR.
 682 * `err` must not be null.
 683 */
 684char *compute_alternate_path(const char *path, struct strbuf *err)
 685{
 686        char *ref_git = NULL;
 687        const char *repo, *ref_git_s;
 688        int seen_error = 0;
 689
 690        ref_git_s = real_path_if_valid(path);
 691        if (!ref_git_s) {
 692                seen_error = 1;
 693                strbuf_addf(err, _("path '%s' does not exist"), path);
 694                goto out;
 695        } else
 696                /*
 697                 * Beware: read_gitfile(), real_path() and mkpath()
 698                 * return static buffer
 699                 */
 700                ref_git = xstrdup(ref_git_s);
 701
 702        repo = read_gitfile(ref_git);
 703        if (!repo)
 704                repo = read_gitfile(mkpath("%s/.git", ref_git));
 705        if (repo) {
 706                free(ref_git);
 707                ref_git = xstrdup(repo);
 708        }
 709
 710        if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 711                char *ref_git_git = mkpathdup("%s/.git", ref_git);
 712                free(ref_git);
 713                ref_git = ref_git_git;
 714        } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 715                struct strbuf sb = STRBUF_INIT;
 716                seen_error = 1;
 717                if (get_common_dir(&sb, ref_git)) {
 718                        strbuf_addf(err,
 719                                    _("reference repository '%s' as a linked "
 720                                      "checkout is not supported yet."),
 721                                    path);
 722                        goto out;
 723                }
 724
 725                strbuf_addf(err, _("reference repository '%s' is not a "
 726                                        "local repository."), path);
 727                goto out;
 728        }
 729
 730        if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 731                strbuf_addf(err, _("reference repository '%s' is shallow"),
 732                            path);
 733                seen_error = 1;
 734                goto out;
 735        }
 736
 737        if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 738                strbuf_addf(err,
 739                            _("reference repository '%s' is grafted"),
 740                            path);
 741                seen_error = 1;
 742                goto out;
 743        }
 744
 745out:
 746        if (seen_error) {
 747                FREE_AND_NULL(ref_git);
 748        }
 749
 750        return ref_git;
 751}
 752
 753int foreach_alt_odb(alt_odb_fn fn, void *cb)
 754{
 755        struct alternate_object_database *ent;
 756        int r = 0;
 757
 758        prepare_alt_odb(the_repository);
 759        for (ent = the_repository->objects->alt_odb_list; ent; ent = ent->next) {
 760                r = fn(ent, cb);
 761                if (r)
 762                        break;
 763        }
 764        return r;
 765}
 766
 767void prepare_alt_odb(struct repository *r)
 768{
 769        if (r->objects->alt_odb_tail)
 770                return;
 771
 772        r->objects->alt_odb_tail = &r->objects->alt_odb_list;
 773        link_alt_odb_entries(r, r->objects->alternate_db, PATH_SEP, NULL, 0);
 774
 775        read_info_alternates(r, r->objects->objectdir, 0);
 776}
 777
 778/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 779static int freshen_file(const char *fn)
 780{
 781        struct utimbuf t;
 782        t.actime = t.modtime = time(NULL);
 783        return !utime(fn, &t);
 784}
 785
 786/*
 787 * All of the check_and_freshen functions return 1 if the file exists and was
 788 * freshened (if freshening was requested), 0 otherwise. If they return
 789 * 0, you should not assume that it is safe to skip a write of the object (it
 790 * either does not exist on disk, or has a stale mtime and may be subject to
 791 * pruning).
 792 */
 793int check_and_freshen_file(const char *fn, int freshen)
 794{
 795        if (access(fn, F_OK))
 796                return 0;
 797        if (freshen && !freshen_file(fn))
 798                return 0;
 799        return 1;
 800}
 801
 802static int check_and_freshen_local(const struct object_id *oid, int freshen)
 803{
 804        static struct strbuf buf = STRBUF_INIT;
 805
 806        strbuf_reset(&buf);
 807        sha1_file_name(the_repository, &buf, oid->hash);
 808
 809        return check_and_freshen_file(buf.buf, freshen);
 810}
 811
 812static int check_and_freshen_nonlocal(const struct object_id *oid, int freshen)
 813{
 814        struct alternate_object_database *alt;
 815        prepare_alt_odb(the_repository);
 816        for (alt = the_repository->objects->alt_odb_list; alt; alt = alt->next) {
 817                const char *path = alt_sha1_path(alt, oid->hash);
 818                if (check_and_freshen_file(path, freshen))
 819                        return 1;
 820        }
 821        return 0;
 822}
 823
 824static int check_and_freshen(const struct object_id *oid, int freshen)
 825{
 826        return check_and_freshen_local(oid, freshen) ||
 827               check_and_freshen_nonlocal(oid, freshen);
 828}
 829
 830int has_loose_object_nonlocal(const struct object_id *oid)
 831{
 832        return check_and_freshen_nonlocal(oid, 0);
 833}
 834
 835static int has_loose_object(const struct object_id *oid)
 836{
 837        return check_and_freshen(oid, 0);
 838}
 839
 840static void mmap_limit_check(size_t length)
 841{
 842        static size_t limit = 0;
 843        if (!limit) {
 844                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 845                if (!limit)
 846                        limit = SIZE_MAX;
 847        }
 848        if (length > limit)
 849                die(_("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX),
 850                    (uintmax_t)length, (uintmax_t)limit);
 851}
 852
 853void *xmmap_gently(void *start, size_t length,
 854                  int prot, int flags, int fd, off_t offset)
 855{
 856        void *ret;
 857
 858        mmap_limit_check(length);
 859        ret = mmap(start, length, prot, flags, fd, offset);
 860        if (ret == MAP_FAILED) {
 861                if (!length)
 862                        return NULL;
 863                release_pack_memory(length);
 864                ret = mmap(start, length, prot, flags, fd, offset);
 865        }
 866        return ret;
 867}
 868
 869void *xmmap(void *start, size_t length,
 870        int prot, int flags, int fd, off_t offset)
 871{
 872        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 873        if (ret == MAP_FAILED)
 874                die_errno(_("mmap failed"));
 875        return ret;
 876}
 877
 878/*
 879 * With an in-core object data in "map", rehash it to make sure the
 880 * object name actually matches "sha1" to detect object corruption.
 881 * With "map" == NULL, try reading the object named with "sha1" using
 882 * the streaming interface and rehash it to do the same.
 883 */
 884int check_object_signature(const struct object_id *oid, void *map,
 885                           unsigned long size, const char *type)
 886{
 887        struct object_id real_oid;
 888        enum object_type obj_type;
 889        struct git_istream *st;
 890        git_hash_ctx c;
 891        char hdr[MAX_HEADER_LEN];
 892        int hdrlen;
 893
 894        if (map) {
 895                hash_object_file(map, size, type, &real_oid);
 896                return !oideq(oid, &real_oid) ? -1 : 0;
 897        }
 898
 899        st = open_istream(oid, &obj_type, &size, NULL);
 900        if (!st)
 901                return -1;
 902
 903        /* Generate the header */
 904        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", type_name(obj_type), size) + 1;
 905
 906        /* Sha1.. */
 907        the_hash_algo->init_fn(&c);
 908        the_hash_algo->update_fn(&c, hdr, hdrlen);
 909        for (;;) {
 910                char buf[1024 * 16];
 911                ssize_t readlen = read_istream(st, buf, sizeof(buf));
 912
 913                if (readlen < 0) {
 914                        close_istream(st);
 915                        return -1;
 916                }
 917                if (!readlen)
 918                        break;
 919                the_hash_algo->update_fn(&c, buf, readlen);
 920        }
 921        the_hash_algo->final_fn(real_oid.hash, &c);
 922        close_istream(st);
 923        return !oideq(oid, &real_oid) ? -1 : 0;
 924}
 925
 926int git_open_cloexec(const char *name, int flags)
 927{
 928        int fd;
 929        static int o_cloexec = O_CLOEXEC;
 930
 931        fd = open(name, flags | o_cloexec);
 932        if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 933                /* Try again w/o O_CLOEXEC: the kernel might not support it */
 934                o_cloexec &= ~O_CLOEXEC;
 935                fd = open(name, flags | o_cloexec);
 936        }
 937
 938#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 939        {
 940                static int fd_cloexec = FD_CLOEXEC;
 941
 942                if (!o_cloexec && 0 <= fd && fd_cloexec) {
 943                        /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 944                        int flags = fcntl(fd, F_GETFD);
 945                        if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 946                                fd_cloexec = 0;
 947                }
 948        }
 949#endif
 950        return fd;
 951}
 952
 953/*
 954 * Find "sha1" as a loose object in the local repository or in an alternate.
 955 * Returns 0 on success, negative on failure.
 956 *
 957 * The "path" out-parameter will give the path of the object we found (if any).
 958 * Note that it may point to static storage and is only valid until another
 959 * call to sha1_file_name(), etc.
 960 */
 961static int stat_sha1_file(struct repository *r, const unsigned char *sha1,
 962                          struct stat *st, const char **path)
 963{
 964        struct alternate_object_database *alt;
 965        static struct strbuf buf = STRBUF_INIT;
 966
 967        strbuf_reset(&buf);
 968        sha1_file_name(r, &buf, sha1);
 969        *path = buf.buf;
 970
 971        if (!lstat(*path, st))
 972                return 0;
 973
 974        prepare_alt_odb(r);
 975        errno = ENOENT;
 976        for (alt = r->objects->alt_odb_list; alt; alt = alt->next) {
 977                *path = alt_sha1_path(alt, sha1);
 978                if (!lstat(*path, st))
 979                        return 0;
 980        }
 981
 982        return -1;
 983}
 984
 985/*
 986 * Like stat_sha1_file(), but actually open the object and return the
 987 * descriptor. See the caveats on the "path" parameter above.
 988 */
 989static int open_sha1_file(struct repository *r,
 990                          const unsigned char *sha1, const char **path)
 991{
 992        int fd;
 993        struct alternate_object_database *alt;
 994        int most_interesting_errno;
 995        static struct strbuf buf = STRBUF_INIT;
 996
 997        strbuf_reset(&buf);
 998        sha1_file_name(r, &buf, sha1);
 999        *path = buf.buf;
1000
1001        fd = git_open(*path);
1002        if (fd >= 0)
1003                return fd;
1004        most_interesting_errno = errno;
1005
1006        prepare_alt_odb(r);
1007        for (alt = r->objects->alt_odb_list; alt; alt = alt->next) {
1008                *path = alt_sha1_path(alt, sha1);
1009                fd = git_open(*path);
1010                if (fd >= 0)
1011                        return fd;
1012                if (most_interesting_errno == ENOENT)
1013                        most_interesting_errno = errno;
1014        }
1015        errno = most_interesting_errno;
1016        return -1;
1017}
1018
1019/*
1020 * Map the loose object at "path" if it is not NULL, or the path found by
1021 * searching for a loose object named "sha1".
1022 */
1023static void *map_sha1_file_1(struct repository *r, const char *path,
1024                             const unsigned char *sha1, unsigned long *size)
1025{
1026        void *map;
1027        int fd;
1028
1029        if (path)
1030                fd = git_open(path);
1031        else
1032                fd = open_sha1_file(r, sha1, &path);
1033        map = NULL;
1034        if (fd >= 0) {
1035                struct stat st;
1036
1037                if (!fstat(fd, &st)) {
1038                        *size = xsize_t(st.st_size);
1039                        if (!*size) {
1040                                /* mmap() is forbidden on empty files */
1041                                error(_("object file %s is empty"), path);
1042                                return NULL;
1043                        }
1044                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1045                }
1046                close(fd);
1047        }
1048        return map;
1049}
1050
1051void *map_sha1_file(struct repository *r,
1052                    const unsigned char *sha1, unsigned long *size)
1053{
1054        return map_sha1_file_1(r, NULL, sha1, size);
1055}
1056
1057static int unpack_sha1_short_header(git_zstream *stream,
1058                                    unsigned char *map, unsigned long mapsize,
1059                                    void *buffer, unsigned long bufsiz)
1060{
1061        /* Get the data stream */
1062        memset(stream, 0, sizeof(*stream));
1063        stream->next_in = map;
1064        stream->avail_in = mapsize;
1065        stream->next_out = buffer;
1066        stream->avail_out = bufsiz;
1067
1068        git_inflate_init(stream);
1069        return git_inflate(stream, 0);
1070}
1071
1072int unpack_sha1_header(git_zstream *stream,
1073                       unsigned char *map, unsigned long mapsize,
1074                       void *buffer, unsigned long bufsiz)
1075{
1076        int status = unpack_sha1_short_header(stream, map, mapsize,
1077                                              buffer, bufsiz);
1078
1079        if (status < Z_OK)
1080                return status;
1081
1082        /* Make sure we have the terminating NUL */
1083        if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1084                return -1;
1085        return 0;
1086}
1087
1088static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
1089                                        unsigned long mapsize, void *buffer,
1090                                        unsigned long bufsiz, struct strbuf *header)
1091{
1092        int status;
1093
1094        status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
1095        if (status < Z_OK)
1096                return -1;
1097
1098        /*
1099         * Check if entire header is unpacked in the first iteration.
1100         */
1101        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1102                return 0;
1103
1104        /*
1105         * buffer[0..bufsiz] was not large enough.  Copy the partial
1106         * result out to header, and then append the result of further
1107         * reading the stream.
1108         */
1109        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1110        stream->next_out = buffer;
1111        stream->avail_out = bufsiz;
1112
1113        do {
1114                status = git_inflate(stream, 0);
1115                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1116                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1117                        return 0;
1118                stream->next_out = buffer;
1119                stream->avail_out = bufsiz;
1120        } while (status != Z_STREAM_END);
1121        return -1;
1122}
1123
1124static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1125{
1126        int bytes = strlen(buffer) + 1;
1127        unsigned char *buf = xmallocz(size);
1128        unsigned long n;
1129        int status = Z_OK;
1130
1131        n = stream->total_out - bytes;
1132        if (n > size)
1133                n = size;
1134        memcpy(buf, (char *) buffer + bytes, n);
1135        bytes = n;
1136        if (bytes <= size) {
1137                /*
1138                 * The above condition must be (bytes <= size), not
1139                 * (bytes < size).  In other words, even though we
1140                 * expect no more output and set avail_out to zero,
1141                 * the input zlib stream may have bytes that express
1142                 * "this concludes the stream", and we *do* want to
1143                 * eat that input.
1144                 *
1145                 * Otherwise we would not be able to test that we
1146                 * consumed all the input to reach the expected size;
1147                 * we also want to check that zlib tells us that all
1148                 * went well with status == Z_STREAM_END at the end.
1149                 */
1150                stream->next_out = buf + bytes;
1151                stream->avail_out = size - bytes;
1152                while (status == Z_OK)
1153                        status = git_inflate(stream, Z_FINISH);
1154        }
1155        if (status == Z_STREAM_END && !stream->avail_in) {
1156                git_inflate_end(stream);
1157                return buf;
1158        }
1159
1160        if (status < 0)
1161                error(_("corrupt loose object '%s'"), sha1_to_hex(sha1));
1162        else if (stream->avail_in)
1163                error(_("garbage at end of loose object '%s'"),
1164                      sha1_to_hex(sha1));
1165        free(buf);
1166        return NULL;
1167}
1168
1169/*
1170 * We used to just use "sscanf()", but that's actually way
1171 * too permissive for what we want to check. So do an anal
1172 * object header parse by hand.
1173 */
1174static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1175                               unsigned int flags)
1176{
1177        const char *type_buf = hdr;
1178        unsigned long size;
1179        int type, type_len = 0;
1180
1181        /*
1182         * The type can be of any size but is followed by
1183         * a space.
1184         */
1185        for (;;) {
1186                char c = *hdr++;
1187                if (!c)
1188                        return -1;
1189                if (c == ' ')
1190                        break;
1191                type_len++;
1192        }
1193
1194        type = type_from_string_gently(type_buf, type_len, 1);
1195        if (oi->type_name)
1196                strbuf_add(oi->type_name, type_buf, type_len);
1197        /*
1198         * Set type to 0 if its an unknown object and
1199         * we're obtaining the type using '--allow-unknown-type'
1200         * option.
1201         */
1202        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1203                type = 0;
1204        else if (type < 0)
1205                die(_("invalid object type"));
1206        if (oi->typep)
1207                *oi->typep = type;
1208
1209        /*
1210         * The length must follow immediately, and be in canonical
1211         * decimal format (ie "010" is not valid).
1212         */
1213        size = *hdr++ - '0';
1214        if (size > 9)
1215                return -1;
1216        if (size) {
1217                for (;;) {
1218                        unsigned long c = *hdr - '0';
1219                        if (c > 9)
1220                                break;
1221                        hdr++;
1222                        size = size * 10 + c;
1223                }
1224        }
1225
1226        if (oi->sizep)
1227                *oi->sizep = size;
1228
1229        /*
1230         * The length must be followed by a zero byte
1231         */
1232        return *hdr ? -1 : type;
1233}
1234
1235int parse_sha1_header(const char *hdr, unsigned long *sizep)
1236{
1237        struct object_info oi = OBJECT_INFO_INIT;
1238
1239        oi.sizep = sizep;
1240        return parse_sha1_header_extended(hdr, &oi, 0);
1241}
1242
1243static int sha1_loose_object_info(struct repository *r,
1244                                  const unsigned char *sha1,
1245                                  struct object_info *oi, int flags)
1246{
1247        int status = 0;
1248        unsigned long mapsize;
1249        void *map;
1250        git_zstream stream;
1251        char hdr[MAX_HEADER_LEN];
1252        struct strbuf hdrbuf = STRBUF_INIT;
1253        unsigned long size_scratch;
1254
1255        if (oi->delta_base_sha1)
1256                hashclr(oi->delta_base_sha1);
1257
1258        /*
1259         * If we don't care about type or size, then we don't
1260         * need to look inside the object at all. Note that we
1261         * do not optimize out the stat call, even if the
1262         * caller doesn't care about the disk-size, since our
1263         * return value implicitly indicates whether the
1264         * object even exists.
1265         */
1266        if (!oi->typep && !oi->type_name && !oi->sizep && !oi->contentp) {
1267                const char *path;
1268                struct stat st;
1269                if (stat_sha1_file(r, sha1, &st, &path) < 0)
1270                        return -1;
1271                if (oi->disk_sizep)
1272                        *oi->disk_sizep = st.st_size;
1273                return 0;
1274        }
1275
1276        map = map_sha1_file(r, sha1, &mapsize);
1277        if (!map)
1278                return -1;
1279
1280        if (!oi->sizep)
1281                oi->sizep = &size_scratch;
1282
1283        if (oi->disk_sizep)
1284                *oi->disk_sizep = mapsize;
1285        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1286                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1287                        status = error(_("unable to unpack %s header with --allow-unknown-type"),
1288                                       sha1_to_hex(sha1));
1289        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1290                status = error(_("unable to unpack %s header"),
1291                               sha1_to_hex(sha1));
1292        if (status < 0)
1293                ; /* Do nothing */
1294        else if (hdrbuf.len) {
1295                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1296                        status = error(_("unable to parse %s header with --allow-unknown-type"),
1297                                       sha1_to_hex(sha1));
1298        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1299                status = error(_("unable to parse %s header"), sha1_to_hex(sha1));
1300
1301        if (status >= 0 && oi->contentp) {
1302                *oi->contentp = unpack_sha1_rest(&stream, hdr,
1303                                                 *oi->sizep, sha1);
1304                if (!*oi->contentp) {
1305                        git_inflate_end(&stream);
1306                        status = -1;
1307                }
1308        } else
1309                git_inflate_end(&stream);
1310
1311        munmap(map, mapsize);
1312        if (status && oi->typep)
1313                *oi->typep = status;
1314        if (oi->sizep == &size_scratch)
1315                oi->sizep = NULL;
1316        strbuf_release(&hdrbuf);
1317        oi->whence = OI_LOOSE;
1318        return (status < 0) ? status : 0;
1319}
1320
1321int fetch_if_missing = 1;
1322
1323int oid_object_info_extended(struct repository *r, const struct object_id *oid,
1324                             struct object_info *oi, unsigned flags)
1325{
1326        static struct object_info blank_oi = OBJECT_INFO_INIT;
1327        struct pack_entry e;
1328        int rtype;
1329        const struct object_id *real = oid;
1330        int already_retried = 0;
1331
1332        if (flags & OBJECT_INFO_LOOKUP_REPLACE)
1333                real = lookup_replace_object(r, oid);
1334
1335        if (is_null_oid(real))
1336                return -1;
1337
1338        if (!oi)
1339                oi = &blank_oi;
1340
1341        if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1342                struct cached_object *co = find_cached_object(real);
1343                if (co) {
1344                        if (oi->typep)
1345                                *(oi->typep) = co->type;
1346                        if (oi->sizep)
1347                                *(oi->sizep) = co->size;
1348                        if (oi->disk_sizep)
1349                                *(oi->disk_sizep) = 0;
1350                        if (oi->delta_base_sha1)
1351                                hashclr(oi->delta_base_sha1);
1352                        if (oi->type_name)
1353                                strbuf_addstr(oi->type_name, type_name(co->type));
1354                        if (oi->contentp)
1355                                *oi->contentp = xmemdupz(co->buf, co->size);
1356                        oi->whence = OI_CACHED;
1357                        return 0;
1358                }
1359        }
1360
1361        while (1) {
1362                if (find_pack_entry(r, real, &e))
1363                        break;
1364
1365                if (flags & OBJECT_INFO_IGNORE_LOOSE)
1366                        return -1;
1367
1368                /* Most likely it's a loose object. */
1369                if (!sha1_loose_object_info(r, real->hash, oi, flags))
1370                        return 0;
1371
1372                /* Not a loose object; someone else may have just packed it. */
1373                if (!(flags & OBJECT_INFO_QUICK)) {
1374                        reprepare_packed_git(r);
1375                        if (find_pack_entry(r, real, &e))
1376                                break;
1377                }
1378
1379                /* Check if it is a missing object */
1380                if (fetch_if_missing && repository_format_partial_clone &&
1381                    !already_retried && r == the_repository) {
1382                        /*
1383                         * TODO Investigate having fetch_object() return
1384                         * TODO error/success and stopping the music here.
1385                         * TODO Pass a repository struct through fetch_object,
1386                         * such that arbitrary repositories work.
1387                         */
1388                        fetch_objects(repository_format_partial_clone, real, 1);
1389                        already_retried = 1;
1390                        continue;
1391                }
1392
1393                return -1;
1394        }
1395
1396        if (oi == &blank_oi)
1397                /*
1398                 * We know that the caller doesn't actually need the
1399                 * information below, so return early.
1400                 */
1401                return 0;
1402        rtype = packed_object_info(r, e.p, e.offset, oi);
1403        if (rtype < 0) {
1404                mark_bad_packed_object(e.p, real->hash);
1405                return oid_object_info_extended(r, real, oi, 0);
1406        } else if (oi->whence == OI_PACKED) {
1407                oi->u.packed.offset = e.offset;
1408                oi->u.packed.pack = e.p;
1409                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1410                                         rtype == OBJ_OFS_DELTA);
1411        }
1412
1413        return 0;
1414}
1415
1416/* returns enum object_type or negative */
1417int oid_object_info(struct repository *r,
1418                    const struct object_id *oid,
1419                    unsigned long *sizep)
1420{
1421        enum object_type type;
1422        struct object_info oi = OBJECT_INFO_INIT;
1423
1424        oi.typep = &type;
1425        oi.sizep = sizep;
1426        if (oid_object_info_extended(r, oid, &oi,
1427                                      OBJECT_INFO_LOOKUP_REPLACE) < 0)
1428                return -1;
1429        return type;
1430}
1431
1432static void *read_object(const unsigned char *sha1, enum object_type *type,
1433                         unsigned long *size)
1434{
1435        struct object_id oid;
1436        struct object_info oi = OBJECT_INFO_INIT;
1437        void *content;
1438        oi.typep = type;
1439        oi.sizep = size;
1440        oi.contentp = &content;
1441
1442        hashcpy(oid.hash, sha1);
1443
1444        if (oid_object_info_extended(the_repository, &oid, &oi, 0) < 0)
1445                return NULL;
1446        return content;
1447}
1448
1449int pretend_object_file(void *buf, unsigned long len, enum object_type type,
1450                        struct object_id *oid)
1451{
1452        struct cached_object *co;
1453
1454        hash_object_file(buf, len, type_name(type), oid);
1455        if (has_sha1_file(oid->hash) || find_cached_object(oid))
1456                return 0;
1457        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1458        co = &cached_objects[cached_object_nr++];
1459        co->size = len;
1460        co->type = type;
1461        co->buf = xmalloc(len);
1462        memcpy(co->buf, buf, len);
1463        oidcpy(&co->oid, oid);
1464        return 0;
1465}
1466
1467/*
1468 * This function dies on corrupt objects; the callers who want to
1469 * deal with them should arrange to call read_object() and give error
1470 * messages themselves.
1471 */
1472void *read_object_file_extended(const struct object_id *oid,
1473                                enum object_type *type,
1474                                unsigned long *size,
1475                                int lookup_replace)
1476{
1477        void *data;
1478        const struct packed_git *p;
1479        const char *path;
1480        struct stat st;
1481        const struct object_id *repl = lookup_replace ?
1482                lookup_replace_object(the_repository, oid) : oid;
1483
1484        errno = 0;
1485        data = read_object(repl->hash, type, size);
1486        if (data)
1487                return data;
1488
1489        if (errno && errno != ENOENT)
1490                die_errno(_("failed to read object %s"), oid_to_hex(oid));
1491
1492        /* die if we replaced an object with one that does not exist */
1493        if (repl != oid)
1494                die(_("replacement %s not found for %s"),
1495                    oid_to_hex(repl), oid_to_hex(oid));
1496
1497        if (!stat_sha1_file(the_repository, repl->hash, &st, &path))
1498                die(_("loose object %s (stored in %s) is corrupt"),
1499                    oid_to_hex(repl), path);
1500
1501        if ((p = has_packed_and_bad(repl->hash)) != NULL)
1502                die(_("packed object %s (stored in %s) is corrupt"),
1503                    oid_to_hex(repl), p->pack_name);
1504
1505        return NULL;
1506}
1507
1508void *read_object_with_reference(const struct object_id *oid,
1509                                 const char *required_type_name,
1510                                 unsigned long *size,
1511                                 struct object_id *actual_oid_return)
1512{
1513        enum object_type type, required_type;
1514        void *buffer;
1515        unsigned long isize;
1516        struct object_id actual_oid;
1517
1518        required_type = type_from_string(required_type_name);
1519        oidcpy(&actual_oid, oid);
1520        while (1) {
1521                int ref_length = -1;
1522                const char *ref_type = NULL;
1523
1524                buffer = read_object_file(&actual_oid, &type, &isize);
1525                if (!buffer)
1526                        return NULL;
1527                if (type == required_type) {
1528                        *size = isize;
1529                        if (actual_oid_return)
1530                                oidcpy(actual_oid_return, &actual_oid);
1531                        return buffer;
1532                }
1533                /* Handle references */
1534                else if (type == OBJ_COMMIT)
1535                        ref_type = "tree ";
1536                else if (type == OBJ_TAG)
1537                        ref_type = "object ";
1538                else {
1539                        free(buffer);
1540                        return NULL;
1541                }
1542                ref_length = strlen(ref_type);
1543
1544                if (ref_length + the_hash_algo->hexsz > isize ||
1545                    memcmp(buffer, ref_type, ref_length) ||
1546                    get_oid_hex((char *) buffer + ref_length, &actual_oid)) {
1547                        free(buffer);
1548                        return NULL;
1549                }
1550                free(buffer);
1551                /* Now we have the ID of the referred-to object in
1552                 * actual_oid.  Check again. */
1553        }
1554}
1555
1556static void write_object_file_prepare(const void *buf, unsigned long len,
1557                                      const char *type, struct object_id *oid,
1558                                      char *hdr, int *hdrlen)
1559{
1560        git_hash_ctx c;
1561
1562        /* Generate the header */
1563        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1564
1565        /* Sha1.. */
1566        the_hash_algo->init_fn(&c);
1567        the_hash_algo->update_fn(&c, hdr, *hdrlen);
1568        the_hash_algo->update_fn(&c, buf, len);
1569        the_hash_algo->final_fn(oid->hash, &c);
1570}
1571
1572/*
1573 * Move the just written object into its final resting place.
1574 */
1575int finalize_object_file(const char *tmpfile, const char *filename)
1576{
1577        int ret = 0;
1578
1579        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1580                goto try_rename;
1581        else if (link(tmpfile, filename))
1582                ret = errno;
1583
1584        /*
1585         * Coda hack - coda doesn't like cross-directory links,
1586         * so we fall back to a rename, which will mean that it
1587         * won't be able to check collisions, but that's not a
1588         * big deal.
1589         *
1590         * The same holds for FAT formatted media.
1591         *
1592         * When this succeeds, we just return.  We have nothing
1593         * left to unlink.
1594         */
1595        if (ret && ret != EEXIST) {
1596        try_rename:
1597                if (!rename(tmpfile, filename))
1598                        goto out;
1599                ret = errno;
1600        }
1601        unlink_or_warn(tmpfile);
1602        if (ret) {
1603                if (ret != EEXIST) {
1604                        return error_errno(_("unable to write sha1 filename %s"), filename);
1605                }
1606                /* FIXME!!! Collision check here ? */
1607        }
1608
1609out:
1610        if (adjust_shared_perm(filename))
1611                return error(_("unable to set permission to '%s'"), filename);
1612        return 0;
1613}
1614
1615static int write_buffer(int fd, const void *buf, size_t len)
1616{
1617        if (write_in_full(fd, buf, len) < 0)
1618                return error_errno(_("file write error"));
1619        return 0;
1620}
1621
1622int hash_object_file(const void *buf, unsigned long len, const char *type,
1623                     struct object_id *oid)
1624{
1625        char hdr[MAX_HEADER_LEN];
1626        int hdrlen = sizeof(hdr);
1627        write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1628        return 0;
1629}
1630
1631/* Finalize a file on disk, and close it. */
1632static void close_sha1_file(int fd)
1633{
1634        if (fsync_object_files)
1635                fsync_or_die(fd, "sha1 file");
1636        if (close(fd) != 0)
1637                die_errno(_("error when closing sha1 file"));
1638}
1639
1640/* Size of directory component, including the ending '/' */
1641static inline int directory_size(const char *filename)
1642{
1643        const char *s = strrchr(filename, '/');
1644        if (!s)
1645                return 0;
1646        return s - filename + 1;
1647}
1648
1649/*
1650 * This creates a temporary file in the same directory as the final
1651 * 'filename'
1652 *
1653 * We want to avoid cross-directory filename renames, because those
1654 * can have problems on various filesystems (FAT, NFS, Coda).
1655 */
1656static int create_tmpfile(struct strbuf *tmp, const char *filename)
1657{
1658        int fd, dirlen = directory_size(filename);
1659
1660        strbuf_reset(tmp);
1661        strbuf_add(tmp, filename, dirlen);
1662        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1663        fd = git_mkstemp_mode(tmp->buf, 0444);
1664        if (fd < 0 && dirlen && errno == ENOENT) {
1665                /*
1666                 * Make sure the directory exists; note that the contents
1667                 * of the buffer are undefined after mkstemp returns an
1668                 * error, so we have to rewrite the whole buffer from
1669                 * scratch.
1670                 */
1671                strbuf_reset(tmp);
1672                strbuf_add(tmp, filename, dirlen - 1);
1673                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1674                        return -1;
1675                if (adjust_shared_perm(tmp->buf))
1676                        return -1;
1677
1678                /* Try again */
1679                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1680                fd = git_mkstemp_mode(tmp->buf, 0444);
1681        }
1682        return fd;
1683}
1684
1685static int write_loose_object(const struct object_id *oid, char *hdr,
1686                              int hdrlen, const void *buf, unsigned long len,
1687                              time_t mtime)
1688{
1689        int fd, ret;
1690        unsigned char compressed[4096];
1691        git_zstream stream;
1692        git_hash_ctx c;
1693        struct object_id parano_oid;
1694        static struct strbuf tmp_file = STRBUF_INIT;
1695        static struct strbuf filename = STRBUF_INIT;
1696
1697        strbuf_reset(&filename);
1698        sha1_file_name(the_repository, &filename, oid->hash);
1699
1700        fd = create_tmpfile(&tmp_file, filename.buf);
1701        if (fd < 0) {
1702                if (errno == EACCES)
1703                        return error(_("insufficient permission for adding an object to repository database %s"), get_object_directory());
1704                else
1705                        return error_errno(_("unable to create temporary file"));
1706        }
1707
1708        /* Set it up */
1709        git_deflate_init(&stream, zlib_compression_level);
1710        stream.next_out = compressed;
1711        stream.avail_out = sizeof(compressed);
1712        the_hash_algo->init_fn(&c);
1713
1714        /* First header.. */
1715        stream.next_in = (unsigned char *)hdr;
1716        stream.avail_in = hdrlen;
1717        while (git_deflate(&stream, 0) == Z_OK)
1718                ; /* nothing */
1719        the_hash_algo->update_fn(&c, hdr, hdrlen);
1720
1721        /* Then the data itself.. */
1722        stream.next_in = (void *)buf;
1723        stream.avail_in = len;
1724        do {
1725                unsigned char *in0 = stream.next_in;
1726                ret = git_deflate(&stream, Z_FINISH);
1727                the_hash_algo->update_fn(&c, in0, stream.next_in - in0);
1728                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1729                        die(_("unable to write sha1 file"));
1730                stream.next_out = compressed;
1731                stream.avail_out = sizeof(compressed);
1732        } while (ret == Z_OK);
1733
1734        if (ret != Z_STREAM_END)
1735                die(_("unable to deflate new object %s (%d)"), oid_to_hex(oid),
1736                    ret);
1737        ret = git_deflate_end_gently(&stream);
1738        if (ret != Z_OK)
1739                die(_("deflateEnd on object %s failed (%d)"), oid_to_hex(oid),
1740                    ret);
1741        the_hash_algo->final_fn(parano_oid.hash, &c);
1742        if (!oideq(oid, &parano_oid))
1743                die(_("confused by unstable object source data for %s"),
1744                    oid_to_hex(oid));
1745
1746        close_sha1_file(fd);
1747
1748        if (mtime) {
1749                struct utimbuf utb;
1750                utb.actime = mtime;
1751                utb.modtime = mtime;
1752                if (utime(tmp_file.buf, &utb) < 0)
1753                        warning_errno(_("failed utime() on %s"), tmp_file.buf);
1754        }
1755
1756        return finalize_object_file(tmp_file.buf, filename.buf);
1757}
1758
1759static int freshen_loose_object(const struct object_id *oid)
1760{
1761        return check_and_freshen(oid, 1);
1762}
1763
1764static int freshen_packed_object(const struct object_id *oid)
1765{
1766        struct pack_entry e;
1767        if (!find_pack_entry(the_repository, oid, &e))
1768                return 0;
1769        if (e.p->freshened)
1770                return 1;
1771        if (!freshen_file(e.p->pack_name))
1772                return 0;
1773        e.p->freshened = 1;
1774        return 1;
1775}
1776
1777int write_object_file(const void *buf, unsigned long len, const char *type,
1778                      struct object_id *oid)
1779{
1780        char hdr[MAX_HEADER_LEN];
1781        int hdrlen = sizeof(hdr);
1782
1783        /* Normally if we have it in the pack then we do not bother writing
1784         * it out into .git/objects/??/?{38} file.
1785         */
1786        write_object_file_prepare(buf, len, type, oid, hdr, &hdrlen);
1787        if (freshen_packed_object(oid) || freshen_loose_object(oid))
1788                return 0;
1789        return write_loose_object(oid, hdr, hdrlen, buf, len, 0);
1790}
1791
1792int hash_object_file_literally(const void *buf, unsigned long len,
1793                               const char *type, struct object_id *oid,
1794                               unsigned flags)
1795{
1796        char *header;
1797        int hdrlen, status = 0;
1798
1799        /* type string, SP, %lu of the length plus NUL must fit this */
1800        hdrlen = strlen(type) + MAX_HEADER_LEN;
1801        header = xmalloc(hdrlen);
1802        write_object_file_prepare(buf, len, type, oid, header, &hdrlen);
1803
1804        if (!(flags & HASH_WRITE_OBJECT))
1805                goto cleanup;
1806        if (freshen_packed_object(oid) || freshen_loose_object(oid))
1807                goto cleanup;
1808        status = write_loose_object(oid, header, hdrlen, buf, len, 0);
1809
1810cleanup:
1811        free(header);
1812        return status;
1813}
1814
1815int force_object_loose(const struct object_id *oid, time_t mtime)
1816{
1817        void *buf;
1818        unsigned long len;
1819        enum object_type type;
1820        char hdr[MAX_HEADER_LEN];
1821        int hdrlen;
1822        int ret;
1823
1824        if (has_loose_object(oid))
1825                return 0;
1826        buf = read_object(oid->hash, &type, &len);
1827        if (!buf)
1828                return error(_("cannot read sha1_file for %s"), oid_to_hex(oid));
1829        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", type_name(type), len) + 1;
1830        ret = write_loose_object(oid, hdr, hdrlen, buf, len, mtime);
1831        free(buf);
1832
1833        return ret;
1834}
1835
1836int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1837{
1838        struct object_id oid;
1839        if (!startup_info->have_repository)
1840                return 0;
1841        hashcpy(oid.hash, sha1);
1842        return oid_object_info_extended(the_repository, &oid, NULL,
1843                                        flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1844}
1845
1846int has_object_file(const struct object_id *oid)
1847{
1848        return has_sha1_file(oid->hash);
1849}
1850
1851int has_object_file_with_flags(const struct object_id *oid, int flags)
1852{
1853        return has_sha1_file_with_flags(oid->hash, flags);
1854}
1855
1856static void check_tree(const void *buf, size_t size)
1857{
1858        struct tree_desc desc;
1859        struct name_entry entry;
1860
1861        init_tree_desc(&desc, buf, size);
1862        while (tree_entry(&desc, &entry))
1863                /* do nothing
1864                 * tree_entry() will die() on malformed entries */
1865                ;
1866}
1867
1868static void check_commit(const void *buf, size_t size)
1869{
1870        struct commit c;
1871        memset(&c, 0, sizeof(c));
1872        if (parse_commit_buffer(the_repository, &c, buf, size, 0))
1873                die(_("corrupt commit"));
1874}
1875
1876static void check_tag(const void *buf, size_t size)
1877{
1878        struct tag t;
1879        memset(&t, 0, sizeof(t));
1880        if (parse_tag_buffer(the_repository, &t, buf, size))
1881                die(_("corrupt tag"));
1882}
1883
1884static int index_mem(struct object_id *oid, void *buf, size_t size,
1885                     enum object_type type,
1886                     const char *path, unsigned flags)
1887{
1888        int ret, re_allocated = 0;
1889        int write_object = flags & HASH_WRITE_OBJECT;
1890
1891        if (!type)
1892                type = OBJ_BLOB;
1893
1894        /*
1895         * Convert blobs to git internal format
1896         */
1897        if ((type == OBJ_BLOB) && path) {
1898                struct strbuf nbuf = STRBUF_INIT;
1899                if (convert_to_git(&the_index, path, buf, size, &nbuf,
1900                                   get_conv_flags(flags))) {
1901                        buf = strbuf_detach(&nbuf, &size);
1902                        re_allocated = 1;
1903                }
1904        }
1905        if (flags & HASH_FORMAT_CHECK) {
1906                if (type == OBJ_TREE)
1907                        check_tree(buf, size);
1908                if (type == OBJ_COMMIT)
1909                        check_commit(buf, size);
1910                if (type == OBJ_TAG)
1911                        check_tag(buf, size);
1912        }
1913
1914        if (write_object)
1915                ret = write_object_file(buf, size, type_name(type), oid);
1916        else
1917                ret = hash_object_file(buf, size, type_name(type), oid);
1918        if (re_allocated)
1919                free(buf);
1920        return ret;
1921}
1922
1923static int index_stream_convert_blob(struct object_id *oid, int fd,
1924                                     const char *path, unsigned flags)
1925{
1926        int ret;
1927        const int write_object = flags & HASH_WRITE_OBJECT;
1928        struct strbuf sbuf = STRBUF_INIT;
1929
1930        assert(path);
1931        assert(would_convert_to_git_filter_fd(&the_index, path));
1932
1933        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1934                                 get_conv_flags(flags));
1935
1936        if (write_object)
1937                ret = write_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
1938                                        oid);
1939        else
1940                ret = hash_object_file(sbuf.buf, sbuf.len, type_name(OBJ_BLOB),
1941                                       oid);
1942        strbuf_release(&sbuf);
1943        return ret;
1944}
1945
1946static int index_pipe(struct object_id *oid, int fd, enum object_type type,
1947                      const char *path, unsigned flags)
1948{
1949        struct strbuf sbuf = STRBUF_INIT;
1950        int ret;
1951
1952        if (strbuf_read(&sbuf, fd, 4096) >= 0)
1953                ret = index_mem(oid, sbuf.buf, sbuf.len, type, path, flags);
1954        else
1955                ret = -1;
1956        strbuf_release(&sbuf);
1957        return ret;
1958}
1959
1960#define SMALL_FILE_SIZE (32*1024)
1961
1962static int index_core(struct object_id *oid, int fd, size_t size,
1963                      enum object_type type, const char *path,
1964                      unsigned flags)
1965{
1966        int ret;
1967
1968        if (!size) {
1969                ret = index_mem(oid, "", size, type, path, flags);
1970        } else if (size <= SMALL_FILE_SIZE) {
1971                char *buf = xmalloc(size);
1972                ssize_t read_result = read_in_full(fd, buf, size);
1973                if (read_result < 0)
1974                        ret = error_errno(_("read error while indexing %s"),
1975                                          path ? path : "<unknown>");
1976                else if (read_result != size)
1977                        ret = error(_("short read while indexing %s"),
1978                                    path ? path : "<unknown>");
1979                else
1980                        ret = index_mem(oid, buf, size, type, path, flags);
1981                free(buf);
1982        } else {
1983                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1984                ret = index_mem(oid, buf, size, type, path, flags);
1985                munmap(buf, size);
1986        }
1987        return ret;
1988}
1989
1990/*
1991 * This creates one packfile per large blob unless bulk-checkin
1992 * machinery is "plugged".
1993 *
1994 * This also bypasses the usual "convert-to-git" dance, and that is on
1995 * purpose. We could write a streaming version of the converting
1996 * functions and insert that before feeding the data to fast-import
1997 * (or equivalent in-core API described above). However, that is
1998 * somewhat complicated, as we do not know the size of the filter
1999 * result, which we need to know beforehand when writing a git object.
2000 * Since the primary motivation for trying to stream from the working
2001 * tree file and to avoid mmaping it in core is to deal with large
2002 * binary blobs, they generally do not want to get any conversion, and
2003 * callers should avoid this code path when filters are requested.
2004 */
2005static int index_stream(struct object_id *oid, int fd, size_t size,
2006                        enum object_type type, const char *path,
2007                        unsigned flags)
2008{
2009        return index_bulk_checkin(oid, fd, size, type, path, flags);
2010}
2011
2012int index_fd(struct object_id *oid, int fd, struct stat *st,
2013             enum object_type type, const char *path, unsigned flags)
2014{
2015        int ret;
2016
2017        /*
2018         * Call xsize_t() only when needed to avoid potentially unnecessary
2019         * die() for large files.
2020         */
2021        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(&the_index, path))
2022                ret = index_stream_convert_blob(oid, fd, path, flags);
2023        else if (!S_ISREG(st->st_mode))
2024                ret = index_pipe(oid, fd, type, path, flags);
2025        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
2026                 (path && would_convert_to_git(&the_index, path)))
2027                ret = index_core(oid, fd, xsize_t(st->st_size), type, path,
2028                                 flags);
2029        else
2030                ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
2031                                   flags);
2032        close(fd);
2033        return ret;
2034}
2035
2036int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
2037{
2038        int fd;
2039        struct strbuf sb = STRBUF_INIT;
2040        int rc = 0;
2041
2042        switch (st->st_mode & S_IFMT) {
2043        case S_IFREG:
2044                fd = open(path, O_RDONLY);
2045                if (fd < 0)
2046                        return error_errno("open(\"%s\")", path);
2047                if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
2048                        return error(_("%s: failed to insert into database"),
2049                                     path);
2050                break;
2051        case S_IFLNK:
2052                if (strbuf_readlink(&sb, path, st->st_size))
2053                        return error_errno("readlink(\"%s\")", path);
2054                if (!(flags & HASH_WRITE_OBJECT))
2055                        hash_object_file(sb.buf, sb.len, blob_type, oid);
2056                else if (write_object_file(sb.buf, sb.len, blob_type, oid))
2057                        rc = error(_("%s: failed to insert into database"), path);
2058                strbuf_release(&sb);
2059                break;
2060        case S_IFDIR:
2061                return resolve_gitlink_ref(path, "HEAD", oid);
2062        default:
2063                return error(_("%s: unsupported file type"), path);
2064        }
2065        return rc;
2066}
2067
2068int read_pack_header(int fd, struct pack_header *header)
2069{
2070        if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
2071                /* "eof before pack header was fully read" */
2072                return PH_ERROR_EOF;
2073
2074        if (header->hdr_signature != htonl(PACK_SIGNATURE))
2075                /* "protocol error (pack signature mismatch detected)" */
2076                return PH_ERROR_PACK_SIGNATURE;
2077        if (!pack_version_ok(header->hdr_version))
2078                /* "protocol error (pack version unsupported)" */
2079                return PH_ERROR_PROTOCOL;
2080        return 0;
2081}
2082
2083void assert_oid_type(const struct object_id *oid, enum object_type expect)
2084{
2085        enum object_type type = oid_object_info(the_repository, oid, NULL);
2086        if (type < 0)
2087                die(_("%s is not a valid object"), oid_to_hex(oid));
2088        if (type != expect)
2089                die(_("%s is not a valid '%s' object"), oid_to_hex(oid),
2090                    type_name(expect));
2091}
2092
2093int for_each_file_in_obj_subdir(unsigned int subdir_nr,
2094                                struct strbuf *path,
2095                                each_loose_object_fn obj_cb,
2096                                each_loose_cruft_fn cruft_cb,
2097                                each_loose_subdir_fn subdir_cb,
2098                                void *data)
2099{
2100        size_t origlen, baselen;
2101        DIR *dir;
2102        struct dirent *de;
2103        int r = 0;
2104        struct object_id oid;
2105
2106        if (subdir_nr > 0xff)
2107                BUG("invalid loose object subdirectory: %x", subdir_nr);
2108
2109        origlen = path->len;
2110        strbuf_complete(path, '/');
2111        strbuf_addf(path, "%02x", subdir_nr);
2112
2113        dir = opendir(path->buf);
2114        if (!dir) {
2115                if (errno != ENOENT)
2116                        r = error_errno(_("unable to open %s"), path->buf);
2117                strbuf_setlen(path, origlen);
2118                return r;
2119        }
2120
2121        oid.hash[0] = subdir_nr;
2122        strbuf_addch(path, '/');
2123        baselen = path->len;
2124
2125        while ((de = readdir(dir))) {
2126                size_t namelen;
2127                if (is_dot_or_dotdot(de->d_name))
2128                        continue;
2129
2130                namelen = strlen(de->d_name);
2131                strbuf_setlen(path, baselen);
2132                strbuf_add(path, de->d_name, namelen);
2133                if (namelen == the_hash_algo->hexsz - 2 &&
2134                    !hex_to_bytes(oid.hash + 1, de->d_name,
2135                                  the_hash_algo->rawsz - 1)) {
2136                        if (obj_cb) {
2137                                r = obj_cb(&oid, path->buf, data);
2138                                if (r)
2139                                        break;
2140                        }
2141                        continue;
2142                }
2143
2144                if (cruft_cb) {
2145                        r = cruft_cb(de->d_name, path->buf, data);
2146                        if (r)
2147                                break;
2148                }
2149        }
2150        closedir(dir);
2151
2152        strbuf_setlen(path, baselen - 1);
2153        if (!r && subdir_cb)
2154                r = subdir_cb(subdir_nr, path->buf, data);
2155
2156        strbuf_setlen(path, origlen);
2157
2158        return r;
2159}
2160
2161int for_each_loose_file_in_objdir_buf(struct strbuf *path,
2162                            each_loose_object_fn obj_cb,
2163                            each_loose_cruft_fn cruft_cb,
2164                            each_loose_subdir_fn subdir_cb,
2165                            void *data)
2166{
2167        int r = 0;
2168        int i;
2169
2170        for (i = 0; i < 256; i++) {
2171                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
2172                                                subdir_cb, data);
2173                if (r)
2174                        break;
2175        }
2176
2177        return r;
2178}
2179
2180int for_each_loose_file_in_objdir(const char *path,
2181                                  each_loose_object_fn obj_cb,
2182                                  each_loose_cruft_fn cruft_cb,
2183                                  each_loose_subdir_fn subdir_cb,
2184                                  void *data)
2185{
2186        struct strbuf buf = STRBUF_INIT;
2187        int r;
2188
2189        strbuf_addstr(&buf, path);
2190        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
2191                                              subdir_cb, data);
2192        strbuf_release(&buf);
2193
2194        return r;
2195}
2196
2197struct loose_alt_odb_data {
2198        each_loose_object_fn *cb;
2199        void *data;
2200};
2201
2202static int loose_from_alt_odb(struct alternate_object_database *alt,
2203                              void *vdata)
2204{
2205        struct loose_alt_odb_data *data = vdata;
2206        struct strbuf buf = STRBUF_INIT;
2207        int r;
2208
2209        strbuf_addstr(&buf, alt->path);
2210        r = for_each_loose_file_in_objdir_buf(&buf,
2211                                              data->cb, NULL, NULL,
2212                                              data->data);
2213        strbuf_release(&buf);
2214        return r;
2215}
2216
2217int for_each_loose_object(each_loose_object_fn cb, void *data,
2218                          enum for_each_object_flags flags)
2219{
2220        struct loose_alt_odb_data alt;
2221        int r;
2222
2223        r = for_each_loose_file_in_objdir(get_object_directory(),
2224                                          cb, NULL, NULL, data);
2225        if (r)
2226                return r;
2227
2228        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2229                return 0;
2230
2231        alt.cb = cb;
2232        alt.data = data;
2233        return foreach_alt_odb(loose_from_alt_odb, &alt);
2234}
2235
2236static int check_stream_sha1(git_zstream *stream,
2237                             const char *hdr,
2238                             unsigned long size,
2239                             const char *path,
2240                             const unsigned char *expected_sha1)
2241{
2242        git_hash_ctx c;
2243        unsigned char real_sha1[GIT_MAX_RAWSZ];
2244        unsigned char buf[4096];
2245        unsigned long total_read;
2246        int status = Z_OK;
2247
2248        the_hash_algo->init_fn(&c);
2249        the_hash_algo->update_fn(&c, hdr, stream->total_out);
2250
2251        /*
2252         * We already read some bytes into hdr, but the ones up to the NUL
2253         * do not count against the object's content size.
2254         */
2255        total_read = stream->total_out - strlen(hdr) - 1;
2256
2257        /*
2258         * This size comparison must be "<=" to read the final zlib packets;
2259         * see the comment in unpack_sha1_rest for details.
2260         */
2261        while (total_read <= size &&
2262               (status == Z_OK || status == Z_BUF_ERROR)) {
2263                stream->next_out = buf;
2264                stream->avail_out = sizeof(buf);
2265                if (size - total_read < stream->avail_out)
2266                        stream->avail_out = size - total_read;
2267                status = git_inflate(stream, Z_FINISH);
2268                the_hash_algo->update_fn(&c, buf, stream->next_out - buf);
2269                total_read += stream->next_out - buf;
2270        }
2271        git_inflate_end(stream);
2272
2273        if (status != Z_STREAM_END) {
2274                error(_("corrupt loose object '%s'"), sha1_to_hex(expected_sha1));
2275                return -1;
2276        }
2277        if (stream->avail_in) {
2278                error(_("garbage at end of loose object '%s'"),
2279                      sha1_to_hex(expected_sha1));
2280                return -1;
2281        }
2282
2283        the_hash_algo->final_fn(real_sha1, &c);
2284        if (!hasheq(expected_sha1, real_sha1)) {
2285                error(_("sha1 mismatch for %s (expected %s)"), path,
2286                      sha1_to_hex(expected_sha1));
2287                return -1;
2288        }
2289
2290        return 0;
2291}
2292
2293int read_loose_object(const char *path,
2294                      const struct object_id *expected_oid,
2295                      enum object_type *type,
2296                      unsigned long *size,
2297                      void **contents)
2298{
2299        int ret = -1;
2300        void *map = NULL;
2301        unsigned long mapsize;
2302        git_zstream stream;
2303        char hdr[MAX_HEADER_LEN];
2304
2305        *contents = NULL;
2306
2307        map = map_sha1_file_1(the_repository, path, NULL, &mapsize);
2308        if (!map) {
2309                error_errno(_("unable to mmap %s"), path);
2310                goto out;
2311        }
2312
2313        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2314                error(_("unable to unpack header of %s"), path);
2315                goto out;
2316        }
2317
2318        *type = parse_sha1_header(hdr, size);
2319        if (*type < 0) {
2320                error(_("unable to parse header of %s"), path);
2321                git_inflate_end(&stream);
2322                goto out;
2323        }
2324
2325        if (*type == OBJ_BLOB && *size > big_file_threshold) {
2326                if (check_stream_sha1(&stream, hdr, *size, path, expected_oid->hash) < 0)
2327                        goto out;
2328        } else {
2329                *contents = unpack_sha1_rest(&stream, hdr, *size, expected_oid->hash);
2330                if (!*contents) {
2331                        error(_("unable to unpack contents of %s"), path);
2332                        git_inflate_end(&stream);
2333                        goto out;
2334                }
2335                if (check_object_signature(expected_oid, *contents,
2336                                         *size, type_name(*type))) {
2337                        error(_("sha1 mismatch for %s (expected %s)"), path,
2338                              oid_to_hex(expected_oid));
2339                        free(*contents);
2340                        goto out;
2341                }
2342        }
2343
2344        ret = 0; /* everything checks out */
2345
2346out:
2347        if (map)
2348                munmap(map, mapsize);
2349        return ret;
2350}