sha1_file.con commit Merge branch 'js/rebase-i-final' (5f3108b)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 *
   6 * This handles basic git sha1 object files - packing, unpacking,
   7 * creation etc.
   8 */
   9#include "cache.h"
  10#include "config.h"
  11#include "string-list.h"
  12#include "lockfile.h"
  13#include "delta.h"
  14#include "pack.h"
  15#include "blob.h"
  16#include "commit.h"
  17#include "run-command.h"
  18#include "tag.h"
  19#include "tree.h"
  20#include "tree-walk.h"
  21#include "refs.h"
  22#include "pack-revindex.h"
  23#include "sha1-lookup.h"
  24#include "bulk-checkin.h"
  25#include "streaming.h"
  26#include "dir.h"
  27#include "mru.h"
  28#include "list.h"
  29#include "mergesort.h"
  30#include "quote.h"
  31#include "packfile.h"
  32
  33const unsigned char null_sha1[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
  42/*
  43 * This is meant to hold a *small* number of objects that you would
  44 * want read_sha1_file() to be able to return, but yet you do not want
  45 * to write them into the object store (e.g. a browse-only
  46 * application).
  47 */
  48static struct cached_object {
  49        unsigned char sha1[20];
  50        enum object_type type;
  51        void *buf;
  52        unsigned long size;
  53} *cached_objects;
  54static int cached_object_nr, cached_object_alloc;
  55
  56static struct cached_object empty_tree = {
  57        EMPTY_TREE_SHA1_BIN_LITERAL,
  58        OBJ_TREE,
  59        "",
  60        0
  61};
  62
  63static struct cached_object *find_cached_object(const unsigned char *sha1)
  64{
  65        int i;
  66        struct cached_object *co = cached_objects;
  67
  68        for (i = 0; i < cached_object_nr; i++, co++) {
  69                if (!hashcmp(co->sha1, sha1))
  70                        return co;
  71        }
  72        if (!hashcmp(sha1, empty_tree.sha1))
  73                return &empty_tree;
  74        return NULL;
  75}
  76
  77int mkdir_in_gitdir(const char *path)
  78{
  79        if (mkdir(path, 0777)) {
  80                int saved_errno = errno;
  81                struct stat st;
  82                struct strbuf sb = STRBUF_INIT;
  83
  84                if (errno != EEXIST)
  85                        return -1;
  86                /*
  87                 * Are we looking at a path in a symlinked worktree
  88                 * whose original repository does not yet have it?
  89                 * e.g. .git/rr-cache pointing at its original
  90                 * repository in which the user hasn't performed any
  91                 * conflict resolution yet?
  92                 */
  93                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
  94                    strbuf_readlink(&sb, path, st.st_size) ||
  95                    !is_absolute_path(sb.buf) ||
  96                    mkdir(sb.buf, 0777)) {
  97                        strbuf_release(&sb);
  98                        errno = saved_errno;
  99                        return -1;
 100                }
 101                strbuf_release(&sb);
 102        }
 103        return adjust_shared_perm(path);
 104}
 105
 106enum scld_error safe_create_leading_directories(char *path)
 107{
 108        char *next_component = path + offset_1st_component(path);
 109        enum scld_error ret = SCLD_OK;
 110
 111        while (ret == SCLD_OK && next_component) {
 112                struct stat st;
 113                char *slash = next_component, slash_character;
 114
 115                while (*slash && !is_dir_sep(*slash))
 116                        slash++;
 117
 118                if (!*slash)
 119                        break;
 120
 121                next_component = slash + 1;
 122                while (is_dir_sep(*next_component))
 123                        next_component++;
 124                if (!*next_component)
 125                        break;
 126
 127                slash_character = *slash;
 128                *slash = '\0';
 129                if (!stat(path, &st)) {
 130                        /* path exists */
 131                        if (!S_ISDIR(st.st_mode)) {
 132                                errno = ENOTDIR;
 133                                ret = SCLD_EXISTS;
 134                        }
 135                } else if (mkdir(path, 0777)) {
 136                        if (errno == EEXIST &&
 137                            !stat(path, &st) && S_ISDIR(st.st_mode))
 138                                ; /* somebody created it since we checked */
 139                        else if (errno == ENOENT)
 140                                /*
 141                                 * Either mkdir() failed because
 142                                 * somebody just pruned the containing
 143                                 * directory, or stat() failed because
 144                                 * the file that was in our way was
 145                                 * just removed.  Either way, inform
 146                                 * the caller that it might be worth
 147                                 * trying again:
 148                                 */
 149                                ret = SCLD_VANISHED;
 150                        else
 151                                ret = SCLD_FAILED;
 152                } else if (adjust_shared_perm(path)) {
 153                        ret = SCLD_PERMS;
 154                }
 155                *slash = slash_character;
 156        }
 157        return ret;
 158}
 159
 160enum scld_error safe_create_leading_directories_const(const char *path)
 161{
 162        int save_errno;
 163        /* path points to cache entries, so xstrdup before messing with it */
 164        char *buf = xstrdup(path);
 165        enum scld_error result = safe_create_leading_directories(buf);
 166
 167        save_errno = errno;
 168        free(buf);
 169        errno = save_errno;
 170        return result;
 171}
 172
 173int raceproof_create_file(const char *path, create_file_fn fn, void *cb)
 174{
 175        /*
 176         * The number of times we will try to remove empty directories
 177         * in the way of path. This is only 1 because if another
 178         * process is racily creating directories that conflict with
 179         * us, we don't want to fight against them.
 180         */
 181        int remove_directories_remaining = 1;
 182
 183        /*
 184         * The number of times that we will try to create the
 185         * directories containing path. We are willing to attempt this
 186         * more than once, because another process could be trying to
 187         * clean up empty directories at the same time as we are
 188         * trying to create them.
 189         */
 190        int create_directories_remaining = 3;
 191
 192        /* A scratch copy of path, filled lazily if we need it: */
 193        struct strbuf path_copy = STRBUF_INIT;
 194
 195        int ret, save_errno;
 196
 197        /* Sanity check: */
 198        assert(*path);
 199
 200retry_fn:
 201        ret = fn(path, cb);
 202        save_errno = errno;
 203        if (!ret)
 204                goto out;
 205
 206        if (errno == EISDIR && remove_directories_remaining-- > 0) {
 207                /*
 208                 * A directory is in the way. Maybe it is empty; try
 209                 * to remove it:
 210                 */
 211                if (!path_copy.len)
 212                        strbuf_addstr(&path_copy, path);
 213
 214                if (!remove_dir_recursively(&path_copy, REMOVE_DIR_EMPTY_ONLY))
 215                        goto retry_fn;
 216        } else if (errno == ENOENT && create_directories_remaining-- > 0) {
 217                /*
 218                 * Maybe the containing directory didn't exist, or
 219                 * maybe it was just deleted by a process that is
 220                 * racing with us to clean up empty directories. Try
 221                 * to create it:
 222                 */
 223                enum scld_error scld_result;
 224
 225                if (!path_copy.len)
 226                        strbuf_addstr(&path_copy, path);
 227
 228                do {
 229                        scld_result = safe_create_leading_directories(path_copy.buf);
 230                        if (scld_result == SCLD_OK)
 231                                goto retry_fn;
 232                } while (scld_result == SCLD_VANISHED && create_directories_remaining-- > 0);
 233        }
 234
 235out:
 236        strbuf_release(&path_copy);
 237        errno = save_errno;
 238        return ret;
 239}
 240
 241static void fill_sha1_path(struct strbuf *buf, const unsigned char *sha1)
 242{
 243        int i;
 244        for (i = 0; i < 20; i++) {
 245                static char hex[] = "0123456789abcdef";
 246                unsigned int val = sha1[i];
 247                strbuf_addch(buf, hex[val >> 4]);
 248                strbuf_addch(buf, hex[val & 0xf]);
 249                if (!i)
 250                        strbuf_addch(buf, '/');
 251        }
 252}
 253
 254const char *sha1_file_name(const unsigned char *sha1)
 255{
 256        static struct strbuf buf = STRBUF_INIT;
 257
 258        strbuf_reset(&buf);
 259        strbuf_addf(&buf, "%s/", get_object_directory());
 260
 261        fill_sha1_path(&buf, sha1);
 262        return buf.buf;
 263}
 264
 265struct strbuf *alt_scratch_buf(struct alternate_object_database *alt)
 266{
 267        strbuf_setlen(&alt->scratch, alt->base_len);
 268        return &alt->scratch;
 269}
 270
 271static const char *alt_sha1_path(struct alternate_object_database *alt,
 272                                 const unsigned char *sha1)
 273{
 274        struct strbuf *buf = alt_scratch_buf(alt);
 275        fill_sha1_path(buf, sha1);
 276        return buf->buf;
 277}
 278
 279struct alternate_object_database *alt_odb_list;
 280static struct alternate_object_database **alt_odb_tail;
 281
 282/*
 283 * Return non-zero iff the path is usable as an alternate object database.
 284 */
 285static int alt_odb_usable(struct strbuf *path, const char *normalized_objdir)
 286{
 287        struct alternate_object_database *alt;
 288
 289        /* Detect cases where alternate disappeared */
 290        if (!is_directory(path->buf)) {
 291                error("object directory %s does not exist; "
 292                      "check .git/objects/info/alternates.",
 293                      path->buf);
 294                return 0;
 295        }
 296
 297        /*
 298         * Prevent the common mistake of listing the same
 299         * thing twice, or object directory itself.
 300         */
 301        for (alt = alt_odb_list; alt; alt = alt->next) {
 302                if (!fspathcmp(path->buf, alt->path))
 303                        return 0;
 304        }
 305        if (!fspathcmp(path->buf, normalized_objdir))
 306                return 0;
 307
 308        return 1;
 309}
 310
 311/*
 312 * Prepare alternate object database registry.
 313 *
 314 * The variable alt_odb_list points at the list of struct
 315 * alternate_object_database.  The elements on this list come from
 316 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 317 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 318 * whose contents is similar to that environment variable but can be
 319 * LF separated.  Its base points at a statically allocated buffer that
 320 * contains "/the/directory/corresponding/to/.git/objects/...", while
 321 * its name points just after the slash at the end of ".git/objects/"
 322 * in the example above, and has enough space to hold 40-byte hex
 323 * SHA1, an extra slash for the first level indirection, and the
 324 * terminating NUL.
 325 */
 326static void read_info_alternates(const char * relative_base, int depth);
 327static int link_alt_odb_entry(const char *entry, const char *relative_base,
 328        int depth, const char *normalized_objdir)
 329{
 330        struct alternate_object_database *ent;
 331        struct strbuf pathbuf = STRBUF_INIT;
 332
 333        if (!is_absolute_path(entry) && relative_base) {
 334                strbuf_realpath(&pathbuf, relative_base, 1);
 335                strbuf_addch(&pathbuf, '/');
 336        }
 337        strbuf_addstr(&pathbuf, entry);
 338
 339        if (strbuf_normalize_path(&pathbuf) < 0 && relative_base) {
 340                error("unable to normalize alternate object path: %s",
 341                      pathbuf.buf);
 342                strbuf_release(&pathbuf);
 343                return -1;
 344        }
 345
 346        /*
 347         * The trailing slash after the directory name is given by
 348         * this function at the end. Remove duplicates.
 349         */
 350        while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
 351                strbuf_setlen(&pathbuf, pathbuf.len - 1);
 352
 353        if (!alt_odb_usable(&pathbuf, normalized_objdir)) {
 354                strbuf_release(&pathbuf);
 355                return -1;
 356        }
 357
 358        ent = alloc_alt_odb(pathbuf.buf);
 359
 360        /* add the alternate entry */
 361        *alt_odb_tail = ent;
 362        alt_odb_tail = &(ent->next);
 363        ent->next = NULL;
 364
 365        /* recursively add alternates */
 366        read_info_alternates(pathbuf.buf, depth + 1);
 367
 368        strbuf_release(&pathbuf);
 369        return 0;
 370}
 371
 372static const char *parse_alt_odb_entry(const char *string,
 373                                       int sep,
 374                                       struct strbuf *out)
 375{
 376        const char *end;
 377
 378        strbuf_reset(out);
 379
 380        if (*string == '#') {
 381                /* comment; consume up to next separator */
 382                end = strchrnul(string, sep);
 383        } else if (*string == '"' && !unquote_c_style(out, string, &end)) {
 384                /*
 385                 * quoted path; unquote_c_style has copied the
 386                 * data for us and set "end". Broken quoting (e.g.,
 387                 * an entry that doesn't end with a quote) falls
 388                 * back to the unquoted case below.
 389                 */
 390        } else {
 391                /* normal, unquoted path */
 392                end = strchrnul(string, sep);
 393                strbuf_add(out, string, end - string);
 394        }
 395
 396        if (*end)
 397                end++;
 398        return end;
 399}
 400
 401static void link_alt_odb_entries(const char *alt, int sep,
 402                                 const char *relative_base, int depth)
 403{
 404        struct strbuf objdirbuf = STRBUF_INIT;
 405        struct strbuf entry = STRBUF_INIT;
 406
 407        if (depth > 5) {
 408                error("%s: ignoring alternate object stores, nesting too deep.",
 409                                relative_base);
 410                return;
 411        }
 412
 413        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 414        if (strbuf_normalize_path(&objdirbuf) < 0)
 415                die("unable to normalize object directory: %s",
 416                    objdirbuf.buf);
 417
 418        while (*alt) {
 419                alt = parse_alt_odb_entry(alt, sep, &entry);
 420                if (!entry.len)
 421                        continue;
 422                link_alt_odb_entry(entry.buf, relative_base, depth, objdirbuf.buf);
 423        }
 424        strbuf_release(&entry);
 425        strbuf_release(&objdirbuf);
 426}
 427
 428static void read_info_alternates(const char * relative_base, int depth)
 429{
 430        char *path;
 431        struct strbuf buf = STRBUF_INIT;
 432
 433        path = xstrfmt("%s/info/alternates", relative_base);
 434        if (strbuf_read_file(&buf, path, 1024) < 0) {
 435                warn_on_fopen_errors(path);
 436                free(path);
 437                return;
 438        }
 439
 440        link_alt_odb_entries(buf.buf, '\n', relative_base, depth);
 441        strbuf_release(&buf);
 442        free(path);
 443}
 444
 445struct alternate_object_database *alloc_alt_odb(const char *dir)
 446{
 447        struct alternate_object_database *ent;
 448
 449        FLEX_ALLOC_STR(ent, path, dir);
 450        strbuf_init(&ent->scratch, 0);
 451        strbuf_addf(&ent->scratch, "%s/", dir);
 452        ent->base_len = ent->scratch.len;
 453
 454        return ent;
 455}
 456
 457void add_to_alternates_file(const char *reference)
 458{
 459        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 460        char *alts = git_pathdup("objects/info/alternates");
 461        FILE *in, *out;
 462
 463        hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
 464        out = fdopen_lock_file(lock, "w");
 465        if (!out)
 466                die_errno("unable to fdopen alternates lockfile");
 467
 468        in = fopen(alts, "r");
 469        if (in) {
 470                struct strbuf line = STRBUF_INIT;
 471                int found = 0;
 472
 473                while (strbuf_getline(&line, in) != EOF) {
 474                        if (!strcmp(reference, line.buf)) {
 475                                found = 1;
 476                                break;
 477                        }
 478                        fprintf_or_die(out, "%s\n", line.buf);
 479                }
 480
 481                strbuf_release(&line);
 482                fclose(in);
 483
 484                if (found) {
 485                        rollback_lock_file(lock);
 486                        lock = NULL;
 487                }
 488        }
 489        else if (errno != ENOENT)
 490                die_errno("unable to read alternates file");
 491
 492        if (lock) {
 493                fprintf_or_die(out, "%s\n", reference);
 494                if (commit_lock_file(lock))
 495                        die_errno("unable to move new alternates file into place");
 496                if (alt_odb_tail)
 497                        link_alt_odb_entries(reference, '\n', NULL, 0);
 498        }
 499        free(alts);
 500}
 501
 502void add_to_alternates_memory(const char *reference)
 503{
 504        /*
 505         * Make sure alternates are initialized, or else our entry may be
 506         * overwritten when they are.
 507         */
 508        prepare_alt_odb();
 509
 510        link_alt_odb_entries(reference, '\n', NULL, 0);
 511}
 512
 513/*
 514 * Compute the exact path an alternate is at and returns it. In case of
 515 * error NULL is returned and the human readable error is added to `err`
 516 * `path` may be relative and should point to $GITDIR.
 517 * `err` must not be null.
 518 */
 519char *compute_alternate_path(const char *path, struct strbuf *err)
 520{
 521        char *ref_git = NULL;
 522        const char *repo, *ref_git_s;
 523        int seen_error = 0;
 524
 525        ref_git_s = real_path_if_valid(path);
 526        if (!ref_git_s) {
 527                seen_error = 1;
 528                strbuf_addf(err, _("path '%s' does not exist"), path);
 529                goto out;
 530        } else
 531                /*
 532                 * Beware: read_gitfile(), real_path() and mkpath()
 533                 * return static buffer
 534                 */
 535                ref_git = xstrdup(ref_git_s);
 536
 537        repo = read_gitfile(ref_git);
 538        if (!repo)
 539                repo = read_gitfile(mkpath("%s/.git", ref_git));
 540        if (repo) {
 541                free(ref_git);
 542                ref_git = xstrdup(repo);
 543        }
 544
 545        if (!repo && is_directory(mkpath("%s/.git/objects", ref_git))) {
 546                char *ref_git_git = mkpathdup("%s/.git", ref_git);
 547                free(ref_git);
 548                ref_git = ref_git_git;
 549        } else if (!is_directory(mkpath("%s/objects", ref_git))) {
 550                struct strbuf sb = STRBUF_INIT;
 551                seen_error = 1;
 552                if (get_common_dir(&sb, ref_git)) {
 553                        strbuf_addf(err,
 554                                    _("reference repository '%s' as a linked "
 555                                      "checkout is not supported yet."),
 556                                    path);
 557                        goto out;
 558                }
 559
 560                strbuf_addf(err, _("reference repository '%s' is not a "
 561                                        "local repository."), path);
 562                goto out;
 563        }
 564
 565        if (!access(mkpath("%s/shallow", ref_git), F_OK)) {
 566                strbuf_addf(err, _("reference repository '%s' is shallow"),
 567                            path);
 568                seen_error = 1;
 569                goto out;
 570        }
 571
 572        if (!access(mkpath("%s/info/grafts", ref_git), F_OK)) {
 573                strbuf_addf(err,
 574                            _("reference repository '%s' is grafted"),
 575                            path);
 576                seen_error = 1;
 577                goto out;
 578        }
 579
 580out:
 581        if (seen_error) {
 582                FREE_AND_NULL(ref_git);
 583        }
 584
 585        return ref_git;
 586}
 587
 588int foreach_alt_odb(alt_odb_fn fn, void *cb)
 589{
 590        struct alternate_object_database *ent;
 591        int r = 0;
 592
 593        prepare_alt_odb();
 594        for (ent = alt_odb_list; ent; ent = ent->next) {
 595                r = fn(ent, cb);
 596                if (r)
 597                        break;
 598        }
 599        return r;
 600}
 601
 602void prepare_alt_odb(void)
 603{
 604        const char *alt;
 605
 606        if (alt_odb_tail)
 607                return;
 608
 609        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 610        if (!alt) alt = "";
 611
 612        alt_odb_tail = &alt_odb_list;
 613        link_alt_odb_entries(alt, PATH_SEP, NULL, 0);
 614
 615        read_info_alternates(get_object_directory(), 0);
 616}
 617
 618/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 619static int freshen_file(const char *fn)
 620{
 621        struct utimbuf t;
 622        t.actime = t.modtime = time(NULL);
 623        return !utime(fn, &t);
 624}
 625
 626/*
 627 * All of the check_and_freshen functions return 1 if the file exists and was
 628 * freshened (if freshening was requested), 0 otherwise. If they return
 629 * 0, you should not assume that it is safe to skip a write of the object (it
 630 * either does not exist on disk, or has a stale mtime and may be subject to
 631 * pruning).
 632 */
 633int check_and_freshen_file(const char *fn, int freshen)
 634{
 635        if (access(fn, F_OK))
 636                return 0;
 637        if (freshen && !freshen_file(fn))
 638                return 0;
 639        return 1;
 640}
 641
 642static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 643{
 644        return check_and_freshen_file(sha1_file_name(sha1), freshen);
 645}
 646
 647static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 648{
 649        struct alternate_object_database *alt;
 650        prepare_alt_odb();
 651        for (alt = alt_odb_list; alt; alt = alt->next) {
 652                const char *path = alt_sha1_path(alt, sha1);
 653                if (check_and_freshen_file(path, freshen))
 654                        return 1;
 655        }
 656        return 0;
 657}
 658
 659static int check_and_freshen(const unsigned char *sha1, int freshen)
 660{
 661        return check_and_freshen_local(sha1, freshen) ||
 662               check_and_freshen_nonlocal(sha1, freshen);
 663}
 664
 665int has_loose_object_nonlocal(const unsigned char *sha1)
 666{
 667        return check_and_freshen_nonlocal(sha1, 0);
 668}
 669
 670static int has_loose_object(const unsigned char *sha1)
 671{
 672        return check_and_freshen(sha1, 0);
 673}
 674
 675static void mmap_limit_check(size_t length)
 676{
 677        static size_t limit = 0;
 678        if (!limit) {
 679                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 680                if (!limit)
 681                        limit = SIZE_MAX;
 682        }
 683        if (length > limit)
 684                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 685                    (uintmax_t)length, (uintmax_t)limit);
 686}
 687
 688void *xmmap_gently(void *start, size_t length,
 689                  int prot, int flags, int fd, off_t offset)
 690{
 691        void *ret;
 692
 693        mmap_limit_check(length);
 694        ret = mmap(start, length, prot, flags, fd, offset);
 695        if (ret == MAP_FAILED) {
 696                if (!length)
 697                        return NULL;
 698                release_pack_memory(length);
 699                ret = mmap(start, length, prot, flags, fd, offset);
 700        }
 701        return ret;
 702}
 703
 704void *xmmap(void *start, size_t length,
 705        int prot, int flags, int fd, off_t offset)
 706{
 707        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 708        if (ret == MAP_FAILED)
 709                die_errno("mmap failed");
 710        return ret;
 711}
 712
 713/*
 714 * With an in-core object data in "map", rehash it to make sure the
 715 * object name actually matches "sha1" to detect object corruption.
 716 * With "map" == NULL, try reading the object named with "sha1" using
 717 * the streaming interface and rehash it to do the same.
 718 */
 719int check_sha1_signature(const unsigned char *sha1, void *map,
 720                         unsigned long size, const char *type)
 721{
 722        unsigned char real_sha1[20];
 723        enum object_type obj_type;
 724        struct git_istream *st;
 725        git_SHA_CTX c;
 726        char hdr[32];
 727        int hdrlen;
 728
 729        if (map) {
 730                hash_sha1_file(map, size, type, real_sha1);
 731                return hashcmp(sha1, real_sha1) ? -1 : 0;
 732        }
 733
 734        st = open_istream(sha1, &obj_type, &size, NULL);
 735        if (!st)
 736                return -1;
 737
 738        /* Generate the header */
 739        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
 740
 741        /* Sha1.. */
 742        git_SHA1_Init(&c);
 743        git_SHA1_Update(&c, hdr, hdrlen);
 744        for (;;) {
 745                char buf[1024 * 16];
 746                ssize_t readlen = read_istream(st, buf, sizeof(buf));
 747
 748                if (readlen < 0) {
 749                        close_istream(st);
 750                        return -1;
 751                }
 752                if (!readlen)
 753                        break;
 754                git_SHA1_Update(&c, buf, readlen);
 755        }
 756        git_SHA1_Final(real_sha1, &c);
 757        close_istream(st);
 758        return hashcmp(sha1, real_sha1) ? -1 : 0;
 759}
 760
 761int git_open_cloexec(const char *name, int flags)
 762{
 763        int fd;
 764        static int o_cloexec = O_CLOEXEC;
 765
 766        fd = open(name, flags | o_cloexec);
 767        if ((o_cloexec & O_CLOEXEC) && fd < 0 && errno == EINVAL) {
 768                /* Try again w/o O_CLOEXEC: the kernel might not support it */
 769                o_cloexec &= ~O_CLOEXEC;
 770                fd = open(name, flags | o_cloexec);
 771        }
 772
 773#if defined(F_GETFD) && defined(F_SETFD) && defined(FD_CLOEXEC)
 774        {
 775                static int fd_cloexec = FD_CLOEXEC;
 776
 777                if (!o_cloexec && 0 <= fd && fd_cloexec) {
 778                        /* Opened w/o O_CLOEXEC?  try with fcntl(2) to add it */
 779                        int flags = fcntl(fd, F_GETFD);
 780                        if (fcntl(fd, F_SETFD, flags | fd_cloexec))
 781                                fd_cloexec = 0;
 782                }
 783        }
 784#endif
 785        return fd;
 786}
 787
 788/*
 789 * Find "sha1" as a loose object in the local repository or in an alternate.
 790 * Returns 0 on success, negative on failure.
 791 *
 792 * The "path" out-parameter will give the path of the object we found (if any).
 793 * Note that it may point to static storage and is only valid until another
 794 * call to sha1_file_name(), etc.
 795 */
 796static int stat_sha1_file(const unsigned char *sha1, struct stat *st,
 797                          const char **path)
 798{
 799        struct alternate_object_database *alt;
 800
 801        *path = sha1_file_name(sha1);
 802        if (!lstat(*path, st))
 803                return 0;
 804
 805        prepare_alt_odb();
 806        errno = ENOENT;
 807        for (alt = alt_odb_list; alt; alt = alt->next) {
 808                *path = alt_sha1_path(alt, sha1);
 809                if (!lstat(*path, st))
 810                        return 0;
 811        }
 812
 813        return -1;
 814}
 815
 816/*
 817 * Like stat_sha1_file(), but actually open the object and return the
 818 * descriptor. See the caveats on the "path" parameter above.
 819 */
 820static int open_sha1_file(const unsigned char *sha1, const char **path)
 821{
 822        int fd;
 823        struct alternate_object_database *alt;
 824        int most_interesting_errno;
 825
 826        *path = sha1_file_name(sha1);
 827        fd = git_open(*path);
 828        if (fd >= 0)
 829                return fd;
 830        most_interesting_errno = errno;
 831
 832        prepare_alt_odb();
 833        for (alt = alt_odb_list; alt; alt = alt->next) {
 834                *path = alt_sha1_path(alt, sha1);
 835                fd = git_open(*path);
 836                if (fd >= 0)
 837                        return fd;
 838                if (most_interesting_errno == ENOENT)
 839                        most_interesting_errno = errno;
 840        }
 841        errno = most_interesting_errno;
 842        return -1;
 843}
 844
 845/*
 846 * Map the loose object at "path" if it is not NULL, or the path found by
 847 * searching for a loose object named "sha1".
 848 */
 849static void *map_sha1_file_1(const char *path,
 850                             const unsigned char *sha1,
 851                             unsigned long *size)
 852{
 853        void *map;
 854        int fd;
 855
 856        if (path)
 857                fd = git_open(path);
 858        else
 859                fd = open_sha1_file(sha1, &path);
 860        map = NULL;
 861        if (fd >= 0) {
 862                struct stat st;
 863
 864                if (!fstat(fd, &st)) {
 865                        *size = xsize_t(st.st_size);
 866                        if (!*size) {
 867                                /* mmap() is forbidden on empty files */
 868                                error("object file %s is empty", path);
 869                                return NULL;
 870                        }
 871                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
 872                }
 873                close(fd);
 874        }
 875        return map;
 876}
 877
 878void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
 879{
 880        return map_sha1_file_1(NULL, sha1, size);
 881}
 882
 883static int unpack_sha1_short_header(git_zstream *stream,
 884                                    unsigned char *map, unsigned long mapsize,
 885                                    void *buffer, unsigned long bufsiz)
 886{
 887        /* Get the data stream */
 888        memset(stream, 0, sizeof(*stream));
 889        stream->next_in = map;
 890        stream->avail_in = mapsize;
 891        stream->next_out = buffer;
 892        stream->avail_out = bufsiz;
 893
 894        git_inflate_init(stream);
 895        return git_inflate(stream, 0);
 896}
 897
 898int unpack_sha1_header(git_zstream *stream,
 899                       unsigned char *map, unsigned long mapsize,
 900                       void *buffer, unsigned long bufsiz)
 901{
 902        int status = unpack_sha1_short_header(stream, map, mapsize,
 903                                              buffer, bufsiz);
 904
 905        if (status < Z_OK)
 906                return status;
 907
 908        /* Make sure we have the terminating NUL */
 909        if (!memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 910                return -1;
 911        return 0;
 912}
 913
 914static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
 915                                        unsigned long mapsize, void *buffer,
 916                                        unsigned long bufsiz, struct strbuf *header)
 917{
 918        int status;
 919
 920        status = unpack_sha1_short_header(stream, map, mapsize, buffer, bufsiz);
 921        if (status < Z_OK)
 922                return -1;
 923
 924        /*
 925         * Check if entire header is unpacked in the first iteration.
 926         */
 927        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 928                return 0;
 929
 930        /*
 931         * buffer[0..bufsiz] was not large enough.  Copy the partial
 932         * result out to header, and then append the result of further
 933         * reading the stream.
 934         */
 935        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 936        stream->next_out = buffer;
 937        stream->avail_out = bufsiz;
 938
 939        do {
 940                status = git_inflate(stream, 0);
 941                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
 942                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
 943                        return 0;
 944                stream->next_out = buffer;
 945                stream->avail_out = bufsiz;
 946        } while (status != Z_STREAM_END);
 947        return -1;
 948}
 949
 950static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
 951{
 952        int bytes = strlen(buffer) + 1;
 953        unsigned char *buf = xmallocz(size);
 954        unsigned long n;
 955        int status = Z_OK;
 956
 957        n = stream->total_out - bytes;
 958        if (n > size)
 959                n = size;
 960        memcpy(buf, (char *) buffer + bytes, n);
 961        bytes = n;
 962        if (bytes <= size) {
 963                /*
 964                 * The above condition must be (bytes <= size), not
 965                 * (bytes < size).  In other words, even though we
 966                 * expect no more output and set avail_out to zero,
 967                 * the input zlib stream may have bytes that express
 968                 * "this concludes the stream", and we *do* want to
 969                 * eat that input.
 970                 *
 971                 * Otherwise we would not be able to test that we
 972                 * consumed all the input to reach the expected size;
 973                 * we also want to check that zlib tells us that all
 974                 * went well with status == Z_STREAM_END at the end.
 975                 */
 976                stream->next_out = buf + bytes;
 977                stream->avail_out = size - bytes;
 978                while (status == Z_OK)
 979                        status = git_inflate(stream, Z_FINISH);
 980        }
 981        if (status == Z_STREAM_END && !stream->avail_in) {
 982                git_inflate_end(stream);
 983                return buf;
 984        }
 985
 986        if (status < 0)
 987                error("corrupt loose object '%s'", sha1_to_hex(sha1));
 988        else if (stream->avail_in)
 989                error("garbage at end of loose object '%s'",
 990                      sha1_to_hex(sha1));
 991        free(buf);
 992        return NULL;
 993}
 994
 995/*
 996 * We used to just use "sscanf()", but that's actually way
 997 * too permissive for what we want to check. So do an anal
 998 * object header parse by hand.
 999 */
1000static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1001                               unsigned int flags)
1002{
1003        const char *type_buf = hdr;
1004        unsigned long size;
1005        int type, type_len = 0;
1006
1007        /*
1008         * The type can be of any size but is followed by
1009         * a space.
1010         */
1011        for (;;) {
1012                char c = *hdr++;
1013                if (!c)
1014                        return -1;
1015                if (c == ' ')
1016                        break;
1017                type_len++;
1018        }
1019
1020        type = type_from_string_gently(type_buf, type_len, 1);
1021        if (oi->typename)
1022                strbuf_add(oi->typename, type_buf, type_len);
1023        /*
1024         * Set type to 0 if its an unknown object and
1025         * we're obtaining the type using '--allow-unknown-type'
1026         * option.
1027         */
1028        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE) && (type < 0))
1029                type = 0;
1030        else if (type < 0)
1031                die("invalid object type");
1032        if (oi->typep)
1033                *oi->typep = type;
1034
1035        /*
1036         * The length must follow immediately, and be in canonical
1037         * decimal format (ie "010" is not valid).
1038         */
1039        size = *hdr++ - '0';
1040        if (size > 9)
1041                return -1;
1042        if (size) {
1043                for (;;) {
1044                        unsigned long c = *hdr - '0';
1045                        if (c > 9)
1046                                break;
1047                        hdr++;
1048                        size = size * 10 + c;
1049                }
1050        }
1051
1052        if (oi->sizep)
1053                *oi->sizep = size;
1054
1055        /*
1056         * The length must be followed by a zero byte
1057         */
1058        return *hdr ? -1 : type;
1059}
1060
1061int parse_sha1_header(const char *hdr, unsigned long *sizep)
1062{
1063        struct object_info oi = OBJECT_INFO_INIT;
1064
1065        oi.sizep = sizep;
1066        return parse_sha1_header_extended(hdr, &oi, 0);
1067}
1068
1069static int sha1_loose_object_info(const unsigned char *sha1,
1070                                  struct object_info *oi,
1071                                  int flags)
1072{
1073        int status = 0;
1074        unsigned long mapsize;
1075        void *map;
1076        git_zstream stream;
1077        char hdr[32];
1078        struct strbuf hdrbuf = STRBUF_INIT;
1079        unsigned long size_scratch;
1080
1081        if (oi->delta_base_sha1)
1082                hashclr(oi->delta_base_sha1);
1083
1084        /*
1085         * If we don't care about type or size, then we don't
1086         * need to look inside the object at all. Note that we
1087         * do not optimize out the stat call, even if the
1088         * caller doesn't care about the disk-size, since our
1089         * return value implicitly indicates whether the
1090         * object even exists.
1091         */
1092        if (!oi->typep && !oi->typename && !oi->sizep && !oi->contentp) {
1093                const char *path;
1094                struct stat st;
1095                if (stat_sha1_file(sha1, &st, &path) < 0)
1096                        return -1;
1097                if (oi->disk_sizep)
1098                        *oi->disk_sizep = st.st_size;
1099                return 0;
1100        }
1101
1102        map = map_sha1_file(sha1, &mapsize);
1103        if (!map)
1104                return -1;
1105
1106        if (!oi->sizep)
1107                oi->sizep = &size_scratch;
1108
1109        if (oi->disk_sizep)
1110                *oi->disk_sizep = mapsize;
1111        if ((flags & OBJECT_INFO_ALLOW_UNKNOWN_TYPE)) {
1112                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
1113                        status = error("unable to unpack %s header with --allow-unknown-type",
1114                                       sha1_to_hex(sha1));
1115        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
1116                status = error("unable to unpack %s header",
1117                               sha1_to_hex(sha1));
1118        if (status < 0)
1119                ; /* Do nothing */
1120        else if (hdrbuf.len) {
1121                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
1122                        status = error("unable to parse %s header with --allow-unknown-type",
1123                                       sha1_to_hex(sha1));
1124        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
1125                status = error("unable to parse %s header", sha1_to_hex(sha1));
1126
1127        if (status >= 0 && oi->contentp)
1128                *oi->contentp = unpack_sha1_rest(&stream, hdr,
1129                                                 *oi->sizep, sha1);
1130        else
1131                git_inflate_end(&stream);
1132
1133        munmap(map, mapsize);
1134        if (status && oi->typep)
1135                *oi->typep = status;
1136        if (oi->sizep == &size_scratch)
1137                oi->sizep = NULL;
1138        strbuf_release(&hdrbuf);
1139        oi->whence = OI_LOOSE;
1140        return (status < 0) ? status : 0;
1141}
1142
1143int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
1144{
1145        static struct object_info blank_oi = OBJECT_INFO_INIT;
1146        struct pack_entry e;
1147        int rtype;
1148        const unsigned char *real = (flags & OBJECT_INFO_LOOKUP_REPLACE) ?
1149                                    lookup_replace_object(sha1) :
1150                                    sha1;
1151
1152        if (!oi)
1153                oi = &blank_oi;
1154
1155        if (!(flags & OBJECT_INFO_SKIP_CACHED)) {
1156                struct cached_object *co = find_cached_object(real);
1157                if (co) {
1158                        if (oi->typep)
1159                                *(oi->typep) = co->type;
1160                        if (oi->sizep)
1161                                *(oi->sizep) = co->size;
1162                        if (oi->disk_sizep)
1163                                *(oi->disk_sizep) = 0;
1164                        if (oi->delta_base_sha1)
1165                                hashclr(oi->delta_base_sha1);
1166                        if (oi->typename)
1167                                strbuf_addstr(oi->typename, typename(co->type));
1168                        if (oi->contentp)
1169                                *oi->contentp = xmemdupz(co->buf, co->size);
1170                        oi->whence = OI_CACHED;
1171                        return 0;
1172                }
1173        }
1174
1175        if (!find_pack_entry(real, &e)) {
1176                /* Most likely it's a loose object. */
1177                if (!sha1_loose_object_info(real, oi, flags))
1178                        return 0;
1179
1180                /* Not a loose object; someone else may have just packed it. */
1181                if (flags & OBJECT_INFO_QUICK) {
1182                        return -1;
1183                } else {
1184                        reprepare_packed_git();
1185                        if (!find_pack_entry(real, &e))
1186                                return -1;
1187                }
1188        }
1189
1190        if (oi == &blank_oi)
1191                /*
1192                 * We know that the caller doesn't actually need the
1193                 * information below, so return early.
1194                 */
1195                return 0;
1196
1197        rtype = packed_object_info(e.p, e.offset, oi);
1198        if (rtype < 0) {
1199                mark_bad_packed_object(e.p, real);
1200                return sha1_object_info_extended(real, oi, 0);
1201        } else if (oi->whence == OI_PACKED) {
1202                oi->u.packed.offset = e.offset;
1203                oi->u.packed.pack = e.p;
1204                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
1205                                         rtype == OBJ_OFS_DELTA);
1206        }
1207
1208        return 0;
1209}
1210
1211/* returns enum object_type or negative */
1212int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
1213{
1214        enum object_type type;
1215        struct object_info oi = OBJECT_INFO_INIT;
1216
1217        oi.typep = &type;
1218        oi.sizep = sizep;
1219        if (sha1_object_info_extended(sha1, &oi,
1220                                      OBJECT_INFO_LOOKUP_REPLACE) < 0)
1221                return -1;
1222        return type;
1223}
1224
1225static void *read_object(const unsigned char *sha1, enum object_type *type,
1226                         unsigned long *size)
1227{
1228        struct object_info oi = OBJECT_INFO_INIT;
1229        void *content;
1230        oi.typep = type;
1231        oi.sizep = size;
1232        oi.contentp = &content;
1233
1234        if (sha1_object_info_extended(sha1, &oi, 0) < 0)
1235                return NULL;
1236        return content;
1237}
1238
1239int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
1240                      unsigned char *sha1)
1241{
1242        struct cached_object *co;
1243
1244        hash_sha1_file(buf, len, typename(type), sha1);
1245        if (has_sha1_file(sha1) || find_cached_object(sha1))
1246                return 0;
1247        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
1248        co = &cached_objects[cached_object_nr++];
1249        co->size = len;
1250        co->type = type;
1251        co->buf = xmalloc(len);
1252        memcpy(co->buf, buf, len);
1253        hashcpy(co->sha1, sha1);
1254        return 0;
1255}
1256
1257/*
1258 * This function dies on corrupt objects; the callers who want to
1259 * deal with them should arrange to call read_object() and give error
1260 * messages themselves.
1261 */
1262void *read_sha1_file_extended(const unsigned char *sha1,
1263                              enum object_type *type,
1264                              unsigned long *size,
1265                              int lookup_replace)
1266{
1267        void *data;
1268        const struct packed_git *p;
1269        const char *path;
1270        struct stat st;
1271        const unsigned char *repl = lookup_replace ? lookup_replace_object(sha1)
1272                                                   : sha1;
1273
1274        errno = 0;
1275        data = read_object(repl, type, size);
1276        if (data)
1277                return data;
1278
1279        if (errno && errno != ENOENT)
1280                die_errno("failed to read object %s", sha1_to_hex(sha1));
1281
1282        /* die if we replaced an object with one that does not exist */
1283        if (repl != sha1)
1284                die("replacement %s not found for %s",
1285                    sha1_to_hex(repl), sha1_to_hex(sha1));
1286
1287        if (!stat_sha1_file(repl, &st, &path))
1288                die("loose object %s (stored in %s) is corrupt",
1289                    sha1_to_hex(repl), path);
1290
1291        if ((p = has_packed_and_bad(repl)) != NULL)
1292                die("packed object %s (stored in %s) is corrupt",
1293                    sha1_to_hex(repl), p->pack_name);
1294
1295        return NULL;
1296}
1297
1298void *read_object_with_reference(const unsigned char *sha1,
1299                                 const char *required_type_name,
1300                                 unsigned long *size,
1301                                 unsigned char *actual_sha1_return)
1302{
1303        enum object_type type, required_type;
1304        void *buffer;
1305        unsigned long isize;
1306        unsigned char actual_sha1[20];
1307
1308        required_type = type_from_string(required_type_name);
1309        hashcpy(actual_sha1, sha1);
1310        while (1) {
1311                int ref_length = -1;
1312                const char *ref_type = NULL;
1313
1314                buffer = read_sha1_file(actual_sha1, &type, &isize);
1315                if (!buffer)
1316                        return NULL;
1317                if (type == required_type) {
1318                        *size = isize;
1319                        if (actual_sha1_return)
1320                                hashcpy(actual_sha1_return, actual_sha1);
1321                        return buffer;
1322                }
1323                /* Handle references */
1324                else if (type == OBJ_COMMIT)
1325                        ref_type = "tree ";
1326                else if (type == OBJ_TAG)
1327                        ref_type = "object ";
1328                else {
1329                        free(buffer);
1330                        return NULL;
1331                }
1332                ref_length = strlen(ref_type);
1333
1334                if (ref_length + 40 > isize ||
1335                    memcmp(buffer, ref_type, ref_length) ||
1336                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
1337                        free(buffer);
1338                        return NULL;
1339                }
1340                free(buffer);
1341                /* Now we have the ID of the referred-to object in
1342                 * actual_sha1.  Check again. */
1343        }
1344}
1345
1346static void write_sha1_file_prepare(const void *buf, unsigned long len,
1347                                    const char *type, unsigned char *sha1,
1348                                    char *hdr, int *hdrlen)
1349{
1350        git_SHA_CTX c;
1351
1352        /* Generate the header */
1353        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
1354
1355        /* Sha1.. */
1356        git_SHA1_Init(&c);
1357        git_SHA1_Update(&c, hdr, *hdrlen);
1358        git_SHA1_Update(&c, buf, len);
1359        git_SHA1_Final(sha1, &c);
1360}
1361
1362/*
1363 * Move the just written object into its final resting place.
1364 */
1365int finalize_object_file(const char *tmpfile, const char *filename)
1366{
1367        int ret = 0;
1368
1369        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
1370                goto try_rename;
1371        else if (link(tmpfile, filename))
1372                ret = errno;
1373
1374        /*
1375         * Coda hack - coda doesn't like cross-directory links,
1376         * so we fall back to a rename, which will mean that it
1377         * won't be able to check collisions, but that's not a
1378         * big deal.
1379         *
1380         * The same holds for FAT formatted media.
1381         *
1382         * When this succeeds, we just return.  We have nothing
1383         * left to unlink.
1384         */
1385        if (ret && ret != EEXIST) {
1386        try_rename:
1387                if (!rename(tmpfile, filename))
1388                        goto out;
1389                ret = errno;
1390        }
1391        unlink_or_warn(tmpfile);
1392        if (ret) {
1393                if (ret != EEXIST) {
1394                        return error_errno("unable to write sha1 filename %s", filename);
1395                }
1396                /* FIXME!!! Collision check here ? */
1397        }
1398
1399out:
1400        if (adjust_shared_perm(filename))
1401                return error("unable to set permission to '%s'", filename);
1402        return 0;
1403}
1404
1405static int write_buffer(int fd, const void *buf, size_t len)
1406{
1407        if (write_in_full(fd, buf, len) < 0)
1408                return error_errno("file write error");
1409        return 0;
1410}
1411
1412int hash_sha1_file(const void *buf, unsigned long len, const char *type,
1413                   unsigned char *sha1)
1414{
1415        char hdr[32];
1416        int hdrlen = sizeof(hdr);
1417        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1418        return 0;
1419}
1420
1421/* Finalize a file on disk, and close it. */
1422static void close_sha1_file(int fd)
1423{
1424        if (fsync_object_files)
1425                fsync_or_die(fd, "sha1 file");
1426        if (close(fd) != 0)
1427                die_errno("error when closing sha1 file");
1428}
1429
1430/* Size of directory component, including the ending '/' */
1431static inline int directory_size(const char *filename)
1432{
1433        const char *s = strrchr(filename, '/');
1434        if (!s)
1435                return 0;
1436        return s - filename + 1;
1437}
1438
1439/*
1440 * This creates a temporary file in the same directory as the final
1441 * 'filename'
1442 *
1443 * We want to avoid cross-directory filename renames, because those
1444 * can have problems on various filesystems (FAT, NFS, Coda).
1445 */
1446static int create_tmpfile(struct strbuf *tmp, const char *filename)
1447{
1448        int fd, dirlen = directory_size(filename);
1449
1450        strbuf_reset(tmp);
1451        strbuf_add(tmp, filename, dirlen);
1452        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
1453        fd = git_mkstemp_mode(tmp->buf, 0444);
1454        if (fd < 0 && dirlen && errno == ENOENT) {
1455                /*
1456                 * Make sure the directory exists; note that the contents
1457                 * of the buffer are undefined after mkstemp returns an
1458                 * error, so we have to rewrite the whole buffer from
1459                 * scratch.
1460                 */
1461                strbuf_reset(tmp);
1462                strbuf_add(tmp, filename, dirlen - 1);
1463                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
1464                        return -1;
1465                if (adjust_shared_perm(tmp->buf))
1466                        return -1;
1467
1468                /* Try again */
1469                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
1470                fd = git_mkstemp_mode(tmp->buf, 0444);
1471        }
1472        return fd;
1473}
1474
1475static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
1476                              const void *buf, unsigned long len, time_t mtime)
1477{
1478        int fd, ret;
1479        unsigned char compressed[4096];
1480        git_zstream stream;
1481        git_SHA_CTX c;
1482        unsigned char parano_sha1[20];
1483        static struct strbuf tmp_file = STRBUF_INIT;
1484        const char *filename = sha1_file_name(sha1);
1485
1486        fd = create_tmpfile(&tmp_file, filename);
1487        if (fd < 0) {
1488                if (errno == EACCES)
1489                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
1490                else
1491                        return error_errno("unable to create temporary file");
1492        }
1493
1494        /* Set it up */
1495        git_deflate_init(&stream, zlib_compression_level);
1496        stream.next_out = compressed;
1497        stream.avail_out = sizeof(compressed);
1498        git_SHA1_Init(&c);
1499
1500        /* First header.. */
1501        stream.next_in = (unsigned char *)hdr;
1502        stream.avail_in = hdrlen;
1503        while (git_deflate(&stream, 0) == Z_OK)
1504                ; /* nothing */
1505        git_SHA1_Update(&c, hdr, hdrlen);
1506
1507        /* Then the data itself.. */
1508        stream.next_in = (void *)buf;
1509        stream.avail_in = len;
1510        do {
1511                unsigned char *in0 = stream.next_in;
1512                ret = git_deflate(&stream, Z_FINISH);
1513                git_SHA1_Update(&c, in0, stream.next_in - in0);
1514                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
1515                        die("unable to write sha1 file");
1516                stream.next_out = compressed;
1517                stream.avail_out = sizeof(compressed);
1518        } while (ret == Z_OK);
1519
1520        if (ret != Z_STREAM_END)
1521                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
1522        ret = git_deflate_end_gently(&stream);
1523        if (ret != Z_OK)
1524                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
1525        git_SHA1_Final(parano_sha1, &c);
1526        if (hashcmp(sha1, parano_sha1) != 0)
1527                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
1528
1529        close_sha1_file(fd);
1530
1531        if (mtime) {
1532                struct utimbuf utb;
1533                utb.actime = mtime;
1534                utb.modtime = mtime;
1535                if (utime(tmp_file.buf, &utb) < 0)
1536                        warning_errno("failed utime() on %s", tmp_file.buf);
1537        }
1538
1539        return finalize_object_file(tmp_file.buf, filename);
1540}
1541
1542static int freshen_loose_object(const unsigned char *sha1)
1543{
1544        return check_and_freshen(sha1, 1);
1545}
1546
1547static int freshen_packed_object(const unsigned char *sha1)
1548{
1549        struct pack_entry e;
1550        if (!find_pack_entry(sha1, &e))
1551                return 0;
1552        if (e.p->freshened)
1553                return 1;
1554        if (!freshen_file(e.p->pack_name))
1555                return 0;
1556        e.p->freshened = 1;
1557        return 1;
1558}
1559
1560int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
1561{
1562        char hdr[32];
1563        int hdrlen = sizeof(hdr);
1564
1565        /* Normally if we have it in the pack then we do not bother writing
1566         * it out into .git/objects/??/?{38} file.
1567         */
1568        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
1569        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
1570                return 0;
1571        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
1572}
1573
1574int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
1575                             struct object_id *oid, unsigned flags)
1576{
1577        char *header;
1578        int hdrlen, status = 0;
1579
1580        /* type string, SP, %lu of the length plus NUL must fit this */
1581        hdrlen = strlen(type) + 32;
1582        header = xmalloc(hdrlen);
1583        write_sha1_file_prepare(buf, len, type, oid->hash, header, &hdrlen);
1584
1585        if (!(flags & HASH_WRITE_OBJECT))
1586                goto cleanup;
1587        if (freshen_packed_object(oid->hash) || freshen_loose_object(oid->hash))
1588                goto cleanup;
1589        status = write_loose_object(oid->hash, header, hdrlen, buf, len, 0);
1590
1591cleanup:
1592        free(header);
1593        return status;
1594}
1595
1596int force_object_loose(const unsigned char *sha1, time_t mtime)
1597{
1598        void *buf;
1599        unsigned long len;
1600        enum object_type type;
1601        char hdr[32];
1602        int hdrlen;
1603        int ret;
1604
1605        if (has_loose_object(sha1))
1606                return 0;
1607        buf = read_object(sha1, &type, &len);
1608        if (!buf)
1609                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
1610        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
1611        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
1612        free(buf);
1613
1614        return ret;
1615}
1616
1617int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
1618{
1619        if (!startup_info->have_repository)
1620                return 0;
1621        return sha1_object_info_extended(sha1, NULL,
1622                                         flags | OBJECT_INFO_SKIP_CACHED) >= 0;
1623}
1624
1625int has_object_file(const struct object_id *oid)
1626{
1627        return has_sha1_file(oid->hash);
1628}
1629
1630int has_object_file_with_flags(const struct object_id *oid, int flags)
1631{
1632        return has_sha1_file_with_flags(oid->hash, flags);
1633}
1634
1635static void check_tree(const void *buf, size_t size)
1636{
1637        struct tree_desc desc;
1638        struct name_entry entry;
1639
1640        init_tree_desc(&desc, buf, size);
1641        while (tree_entry(&desc, &entry))
1642                /* do nothing
1643                 * tree_entry() will die() on malformed entries */
1644                ;
1645}
1646
1647static void check_commit(const void *buf, size_t size)
1648{
1649        struct commit c;
1650        memset(&c, 0, sizeof(c));
1651        if (parse_commit_buffer(&c, buf, size))
1652                die("corrupt commit");
1653}
1654
1655static void check_tag(const void *buf, size_t size)
1656{
1657        struct tag t;
1658        memset(&t, 0, sizeof(t));
1659        if (parse_tag_buffer(&t, buf, size))
1660                die("corrupt tag");
1661}
1662
1663static int index_mem(unsigned char *sha1, void *buf, size_t size,
1664                     enum object_type type,
1665                     const char *path, unsigned flags)
1666{
1667        int ret, re_allocated = 0;
1668        int write_object = flags & HASH_WRITE_OBJECT;
1669
1670        if (!type)
1671                type = OBJ_BLOB;
1672
1673        /*
1674         * Convert blobs to git internal format
1675         */
1676        if ((type == OBJ_BLOB) && path) {
1677                struct strbuf nbuf = STRBUF_INIT;
1678                if (convert_to_git(&the_index, path, buf, size, &nbuf,
1679                                   write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
1680                        buf = strbuf_detach(&nbuf, &size);
1681                        re_allocated = 1;
1682                }
1683        }
1684        if (flags & HASH_FORMAT_CHECK) {
1685                if (type == OBJ_TREE)
1686                        check_tree(buf, size);
1687                if (type == OBJ_COMMIT)
1688                        check_commit(buf, size);
1689                if (type == OBJ_TAG)
1690                        check_tag(buf, size);
1691        }
1692
1693        if (write_object)
1694                ret = write_sha1_file(buf, size, typename(type), sha1);
1695        else
1696                ret = hash_sha1_file(buf, size, typename(type), sha1);
1697        if (re_allocated)
1698                free(buf);
1699        return ret;
1700}
1701
1702static int index_stream_convert_blob(unsigned char *sha1, int fd,
1703                                     const char *path, unsigned flags)
1704{
1705        int ret;
1706        const int write_object = flags & HASH_WRITE_OBJECT;
1707        struct strbuf sbuf = STRBUF_INIT;
1708
1709        assert(path);
1710        assert(would_convert_to_git_filter_fd(path));
1711
1712        convert_to_git_filter_fd(&the_index, path, fd, &sbuf,
1713                                 write_object ? safe_crlf : SAFE_CRLF_FALSE);
1714
1715        if (write_object)
1716                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1717                                      sha1);
1718        else
1719                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
1720                                     sha1);
1721        strbuf_release(&sbuf);
1722        return ret;
1723}
1724
1725static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
1726                      const char *path, unsigned flags)
1727{
1728        struct strbuf sbuf = STRBUF_INIT;
1729        int ret;
1730
1731        if (strbuf_read(&sbuf, fd, 4096) >= 0)
1732                ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
1733        else
1734                ret = -1;
1735        strbuf_release(&sbuf);
1736        return ret;
1737}
1738
1739#define SMALL_FILE_SIZE (32*1024)
1740
1741static int index_core(unsigned char *sha1, int fd, size_t size,
1742                      enum object_type type, const char *path,
1743                      unsigned flags)
1744{
1745        int ret;
1746
1747        if (!size) {
1748                ret = index_mem(sha1, "", size, type, path, flags);
1749        } else if (size <= SMALL_FILE_SIZE) {
1750                char *buf = xmalloc(size);
1751                if (size == read_in_full(fd, buf, size))
1752                        ret = index_mem(sha1, buf, size, type, path, flags);
1753                else
1754                        ret = error_errno("short read");
1755                free(buf);
1756        } else {
1757                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
1758                ret = index_mem(sha1, buf, size, type, path, flags);
1759                munmap(buf, size);
1760        }
1761        return ret;
1762}
1763
1764/*
1765 * This creates one packfile per large blob unless bulk-checkin
1766 * machinery is "plugged".
1767 *
1768 * This also bypasses the usual "convert-to-git" dance, and that is on
1769 * purpose. We could write a streaming version of the converting
1770 * functions and insert that before feeding the data to fast-import
1771 * (or equivalent in-core API described above). However, that is
1772 * somewhat complicated, as we do not know the size of the filter
1773 * result, which we need to know beforehand when writing a git object.
1774 * Since the primary motivation for trying to stream from the working
1775 * tree file and to avoid mmaping it in core is to deal with large
1776 * binary blobs, they generally do not want to get any conversion, and
1777 * callers should avoid this code path when filters are requested.
1778 */
1779static int index_stream(struct object_id *oid, int fd, size_t size,
1780                        enum object_type type, const char *path,
1781                        unsigned flags)
1782{
1783        return index_bulk_checkin(oid->hash, fd, size, type, path, flags);
1784}
1785
1786int index_fd(struct object_id *oid, int fd, struct stat *st,
1787             enum object_type type, const char *path, unsigned flags)
1788{
1789        int ret;
1790
1791        /*
1792         * Call xsize_t() only when needed to avoid potentially unnecessary
1793         * die() for large files.
1794         */
1795        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
1796                ret = index_stream_convert_blob(oid->hash, fd, path, flags);
1797        else if (!S_ISREG(st->st_mode))
1798                ret = index_pipe(oid->hash, fd, type, path, flags);
1799        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
1800                 (path && would_convert_to_git(&the_index, path)))
1801                ret = index_core(oid->hash, fd, xsize_t(st->st_size), type, path,
1802                                 flags);
1803        else
1804                ret = index_stream(oid, fd, xsize_t(st->st_size), type, path,
1805                                   flags);
1806        close(fd);
1807        return ret;
1808}
1809
1810int index_path(struct object_id *oid, const char *path, struct stat *st, unsigned flags)
1811{
1812        int fd;
1813        struct strbuf sb = STRBUF_INIT;
1814        int rc = 0;
1815
1816        switch (st->st_mode & S_IFMT) {
1817        case S_IFREG:
1818                fd = open(path, O_RDONLY);
1819                if (fd < 0)
1820                        return error_errno("open(\"%s\")", path);
1821                if (index_fd(oid, fd, st, OBJ_BLOB, path, flags) < 0)
1822                        return error("%s: failed to insert into database",
1823                                     path);
1824                break;
1825        case S_IFLNK:
1826                if (strbuf_readlink(&sb, path, st->st_size))
1827                        return error_errno("readlink(\"%s\")", path);
1828                if (!(flags & HASH_WRITE_OBJECT))
1829                        hash_sha1_file(sb.buf, sb.len, blob_type, oid->hash);
1830                else if (write_sha1_file(sb.buf, sb.len, blob_type, oid->hash))
1831                        rc = error("%s: failed to insert into database", path);
1832                strbuf_release(&sb);
1833                break;
1834        case S_IFDIR:
1835                return resolve_gitlink_ref(path, "HEAD", oid->hash);
1836        default:
1837                return error("%s: unsupported file type", path);
1838        }
1839        return rc;
1840}
1841
1842int read_pack_header(int fd, struct pack_header *header)
1843{
1844        if (read_in_full(fd, header, sizeof(*header)) != sizeof(*header))
1845                /* "eof before pack header was fully read" */
1846                return PH_ERROR_EOF;
1847
1848        if (header->hdr_signature != htonl(PACK_SIGNATURE))
1849                /* "protocol error (pack signature mismatch detected)" */
1850                return PH_ERROR_PACK_SIGNATURE;
1851        if (!pack_version_ok(header->hdr_version))
1852                /* "protocol error (pack version unsupported)" */
1853                return PH_ERROR_PROTOCOL;
1854        return 0;
1855}
1856
1857void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
1858{
1859        enum object_type type = sha1_object_info(sha1, NULL);
1860        if (type < 0)
1861                die("%s is not a valid object", sha1_to_hex(sha1));
1862        if (type != expect)
1863                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
1864                    typename(expect));
1865}
1866
1867int for_each_file_in_obj_subdir(unsigned int subdir_nr,
1868                                struct strbuf *path,
1869                                each_loose_object_fn obj_cb,
1870                                each_loose_cruft_fn cruft_cb,
1871                                each_loose_subdir_fn subdir_cb,
1872                                void *data)
1873{
1874        size_t origlen, baselen;
1875        DIR *dir;
1876        struct dirent *de;
1877        int r = 0;
1878
1879        if (subdir_nr > 0xff)
1880                BUG("invalid loose object subdirectory: %x", subdir_nr);
1881
1882        origlen = path->len;
1883        strbuf_complete(path, '/');
1884        strbuf_addf(path, "%02x", subdir_nr);
1885        baselen = path->len;
1886
1887        dir = opendir(path->buf);
1888        if (!dir) {
1889                if (errno != ENOENT)
1890                        r = error_errno("unable to open %s", path->buf);
1891                strbuf_setlen(path, origlen);
1892                return r;
1893        }
1894
1895        while ((de = readdir(dir))) {
1896                if (is_dot_or_dotdot(de->d_name))
1897                        continue;
1898
1899                strbuf_setlen(path, baselen);
1900                strbuf_addf(path, "/%s", de->d_name);
1901
1902                if (strlen(de->d_name) == GIT_SHA1_HEXSZ - 2)  {
1903                        char hex[GIT_MAX_HEXSZ+1];
1904                        struct object_id oid;
1905
1906                        xsnprintf(hex, sizeof(hex), "%02x%s",
1907                                  subdir_nr, de->d_name);
1908                        if (!get_oid_hex(hex, &oid)) {
1909                                if (obj_cb) {
1910                                        r = obj_cb(&oid, path->buf, data);
1911                                        if (r)
1912                                                break;
1913                                }
1914                                continue;
1915                        }
1916                }
1917
1918                if (cruft_cb) {
1919                        r = cruft_cb(de->d_name, path->buf, data);
1920                        if (r)
1921                                break;
1922                }
1923        }
1924        closedir(dir);
1925
1926        strbuf_setlen(path, baselen);
1927        if (!r && subdir_cb)
1928                r = subdir_cb(subdir_nr, path->buf, data);
1929
1930        strbuf_setlen(path, origlen);
1931
1932        return r;
1933}
1934
1935int for_each_loose_file_in_objdir_buf(struct strbuf *path,
1936                            each_loose_object_fn obj_cb,
1937                            each_loose_cruft_fn cruft_cb,
1938                            each_loose_subdir_fn subdir_cb,
1939                            void *data)
1940{
1941        int r = 0;
1942        int i;
1943
1944        for (i = 0; i < 256; i++) {
1945                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
1946                                                subdir_cb, data);
1947                if (r)
1948                        break;
1949        }
1950
1951        return r;
1952}
1953
1954int for_each_loose_file_in_objdir(const char *path,
1955                                  each_loose_object_fn obj_cb,
1956                                  each_loose_cruft_fn cruft_cb,
1957                                  each_loose_subdir_fn subdir_cb,
1958                                  void *data)
1959{
1960        struct strbuf buf = STRBUF_INIT;
1961        int r;
1962
1963        strbuf_addstr(&buf, path);
1964        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
1965                                              subdir_cb, data);
1966        strbuf_release(&buf);
1967
1968        return r;
1969}
1970
1971struct loose_alt_odb_data {
1972        each_loose_object_fn *cb;
1973        void *data;
1974};
1975
1976static int loose_from_alt_odb(struct alternate_object_database *alt,
1977                              void *vdata)
1978{
1979        struct loose_alt_odb_data *data = vdata;
1980        struct strbuf buf = STRBUF_INIT;
1981        int r;
1982
1983        strbuf_addstr(&buf, alt->path);
1984        r = for_each_loose_file_in_objdir_buf(&buf,
1985                                              data->cb, NULL, NULL,
1986                                              data->data);
1987        strbuf_release(&buf);
1988        return r;
1989}
1990
1991int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
1992{
1993        struct loose_alt_odb_data alt;
1994        int r;
1995
1996        r = for_each_loose_file_in_objdir(get_object_directory(),
1997                                          cb, NULL, NULL, data);
1998        if (r)
1999                return r;
2000
2001        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
2002                return 0;
2003
2004        alt.cb = cb;
2005        alt.data = data;
2006        return foreach_alt_odb(loose_from_alt_odb, &alt);
2007}
2008
2009static int check_stream_sha1(git_zstream *stream,
2010                             const char *hdr,
2011                             unsigned long size,
2012                             const char *path,
2013                             const unsigned char *expected_sha1)
2014{
2015        git_SHA_CTX c;
2016        unsigned char real_sha1[GIT_MAX_RAWSZ];
2017        unsigned char buf[4096];
2018        unsigned long total_read;
2019        int status = Z_OK;
2020
2021        git_SHA1_Init(&c);
2022        git_SHA1_Update(&c, hdr, stream->total_out);
2023
2024        /*
2025         * We already read some bytes into hdr, but the ones up to the NUL
2026         * do not count against the object's content size.
2027         */
2028        total_read = stream->total_out - strlen(hdr) - 1;
2029
2030        /*
2031         * This size comparison must be "<=" to read the final zlib packets;
2032         * see the comment in unpack_sha1_rest for details.
2033         */
2034        while (total_read <= size &&
2035               (status == Z_OK || status == Z_BUF_ERROR)) {
2036                stream->next_out = buf;
2037                stream->avail_out = sizeof(buf);
2038                if (size - total_read < stream->avail_out)
2039                        stream->avail_out = size - total_read;
2040                status = git_inflate(stream, Z_FINISH);
2041                git_SHA1_Update(&c, buf, stream->next_out - buf);
2042                total_read += stream->next_out - buf;
2043        }
2044        git_inflate_end(stream);
2045
2046        if (status != Z_STREAM_END) {
2047                error("corrupt loose object '%s'", sha1_to_hex(expected_sha1));
2048                return -1;
2049        }
2050        if (stream->avail_in) {
2051                error("garbage at end of loose object '%s'",
2052                      sha1_to_hex(expected_sha1));
2053                return -1;
2054        }
2055
2056        git_SHA1_Final(real_sha1, &c);
2057        if (hashcmp(expected_sha1, real_sha1)) {
2058                error("sha1 mismatch for %s (expected %s)", path,
2059                      sha1_to_hex(expected_sha1));
2060                return -1;
2061        }
2062
2063        return 0;
2064}
2065
2066int read_loose_object(const char *path,
2067                      const unsigned char *expected_sha1,
2068                      enum object_type *type,
2069                      unsigned long *size,
2070                      void **contents)
2071{
2072        int ret = -1;
2073        void *map = NULL;
2074        unsigned long mapsize;
2075        git_zstream stream;
2076        char hdr[32];
2077
2078        *contents = NULL;
2079
2080        map = map_sha1_file_1(path, NULL, &mapsize);
2081        if (!map) {
2082                error_errno("unable to mmap %s", path);
2083                goto out;
2084        }
2085
2086        if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0) {
2087                error("unable to unpack header of %s", path);
2088                goto out;
2089        }
2090
2091        *type = parse_sha1_header(hdr, size);
2092        if (*type < 0) {
2093                error("unable to parse header of %s", path);
2094                git_inflate_end(&stream);
2095                goto out;
2096        }
2097
2098        if (*type == OBJ_BLOB) {
2099                if (check_stream_sha1(&stream, hdr, *size, path, expected_sha1) < 0)
2100                        goto out;
2101        } else {
2102                *contents = unpack_sha1_rest(&stream, hdr, *size, expected_sha1);
2103                if (!*contents) {
2104                        error("unable to unpack contents of %s", path);
2105                        git_inflate_end(&stream);
2106                        goto out;
2107                }
2108                if (check_sha1_signature(expected_sha1, *contents,
2109                                         *size, typename(*type))) {
2110                        error("sha1 mismatch for %s (expected %s)", path,
2111                              sha1_to_hex(expected_sha1));
2112                        free(*contents);
2113                        goto out;
2114                }
2115        }
2116
2117        ret = 0; /* everything checks out */
2118
2119out:
2120        if (map)
2121                munmap(map, mapsize);
2122        return ret;
2123}