c02e785e99cb58eea9e7378f342e3f85a17e042d
   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 "string-list.h"
  11#include "lockfile.h"
  12#include "delta.h"
  13#include "pack.h"
  14#include "blob.h"
  15#include "commit.h"
  16#include "run-command.h"
  17#include "tag.h"
  18#include "tree.h"
  19#include "tree-walk.h"
  20#include "refs.h"
  21#include "pack-revindex.h"
  22#include "sha1-lookup.h"
  23#include "bulk-checkin.h"
  24#include "streaming.h"
  25#include "dir.h"
  26#include "mru.h"
  27#include "list.h"
  28
  29#ifndef O_NOATIME
  30#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  31#define O_NOATIME 01000000
  32#else
  33#define O_NOATIME 0
  34#endif
  35#endif
  36
  37#define SZ_FMT PRIuMAX
  38static inline uintmax_t sz_fmt(size_t s) { return s; }
  39
  40const unsigned char null_sha1[20];
  41const struct object_id null_oid;
  42
  43/*
  44 * This is meant to hold a *small* number of objects that you would
  45 * want read_sha1_file() to be able to return, but yet you do not want
  46 * to write them into the object store (e.g. a browse-only
  47 * application).
  48 */
  49static struct cached_object {
  50        unsigned char sha1[20];
  51        enum object_type type;
  52        void *buf;
  53        unsigned long size;
  54} *cached_objects;
  55static int cached_object_nr, cached_object_alloc;
  56
  57static struct cached_object empty_tree = {
  58        EMPTY_TREE_SHA1_BIN_LITERAL,
  59        OBJ_TREE,
  60        "",
  61        0
  62};
  63
  64static struct cached_object *find_cached_object(const unsigned char *sha1)
  65{
  66        int i;
  67        struct cached_object *co = cached_objects;
  68
  69        for (i = 0; i < cached_object_nr; i++, co++) {
  70                if (!hashcmp(co->sha1, sha1))
  71                        return co;
  72        }
  73        if (!hashcmp(sha1, empty_tree.sha1))
  74                return &empty_tree;
  75        return NULL;
  76}
  77
  78int mkdir_in_gitdir(const char *path)
  79{
  80        if (mkdir(path, 0777)) {
  81                int saved_errno = errno;
  82                struct stat st;
  83                struct strbuf sb = STRBUF_INIT;
  84
  85                if (errno != EEXIST)
  86                        return -1;
  87                /*
  88                 * Are we looking at a path in a symlinked worktree
  89                 * whose original repository does not yet have it?
  90                 * e.g. .git/rr-cache pointing at its original
  91                 * repository in which the user hasn't performed any
  92                 * conflict resolution yet?
  93                 */
  94                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
  95                    strbuf_readlink(&sb, path, st.st_size) ||
  96                    !is_absolute_path(sb.buf) ||
  97                    mkdir(sb.buf, 0777)) {
  98                        strbuf_release(&sb);
  99                        errno = saved_errno;
 100                        return -1;
 101                }
 102                strbuf_release(&sb);
 103        }
 104        return adjust_shared_perm(path);
 105}
 106
 107enum scld_error safe_create_leading_directories(char *path)
 108{
 109        char *next_component = path + offset_1st_component(path);
 110        enum scld_error ret = SCLD_OK;
 111
 112        while (ret == SCLD_OK && next_component) {
 113                struct stat st;
 114                char *slash = next_component, slash_character;
 115
 116                while (*slash && !is_dir_sep(*slash))
 117                        slash++;
 118
 119                if (!*slash)
 120                        break;
 121
 122                next_component = slash + 1;
 123                while (is_dir_sep(*next_component))
 124                        next_component++;
 125                if (!*next_component)
 126                        break;
 127
 128                slash_character = *slash;
 129                *slash = '\0';
 130                if (!stat(path, &st)) {
 131                        /* path exists */
 132                        if (!S_ISDIR(st.st_mode))
 133                                ret = SCLD_EXISTS;
 134                } else if (mkdir(path, 0777)) {
 135                        if (errno == EEXIST &&
 136                            !stat(path, &st) && S_ISDIR(st.st_mode))
 137                                ; /* somebody created it since we checked */
 138                        else if (errno == ENOENT)
 139                                /*
 140                                 * Either mkdir() failed because
 141                                 * somebody just pruned the containing
 142                                 * directory, or stat() failed because
 143                                 * the file that was in our way was
 144                                 * just removed.  Either way, inform
 145                                 * the caller that it might be worth
 146                                 * trying again:
 147                                 */
 148                                ret = SCLD_VANISHED;
 149                        else
 150                                ret = SCLD_FAILED;
 151                } else if (adjust_shared_perm(path)) {
 152                        ret = SCLD_PERMS;
 153                }
 154                *slash = slash_character;
 155        }
 156        return ret;
 157}
 158
 159enum scld_error safe_create_leading_directories_const(const char *path)
 160{
 161        /* path points to cache entries, so xstrdup before messing with it */
 162        char *buf = xstrdup(path);
 163        enum scld_error result = safe_create_leading_directories(buf);
 164        free(buf);
 165        return result;
 166}
 167
 168static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 169{
 170        int i;
 171        for (i = 0; i < 20; i++) {
 172                static char hex[] = "0123456789abcdef";
 173                unsigned int val = sha1[i];
 174                char *pos = pathbuf + i*2 + (i > 0);
 175                *pos++ = hex[val >> 4];
 176                *pos = hex[val & 0xf];
 177        }
 178}
 179
 180const char *sha1_file_name(const unsigned char *sha1)
 181{
 182        static char buf[PATH_MAX];
 183        const char *objdir;
 184        int len;
 185
 186        objdir = get_object_directory();
 187        len = strlen(objdir);
 188
 189        /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
 190        if (len + 43 > PATH_MAX)
 191                die("insanely long object directory %s", objdir);
 192        memcpy(buf, objdir, len);
 193        buf[len] = '/';
 194        buf[len+3] = '/';
 195        buf[len+42] = '\0';
 196        fill_sha1_path(buf + len + 1, sha1);
 197        return buf;
 198}
 199
 200/*
 201 * Return the name of the pack or index file with the specified sha1
 202 * in its filename.  *base and *name are scratch space that must be
 203 * provided by the caller.  which should be "pack" or "idx".
 204 */
 205static char *sha1_get_pack_name(const unsigned char *sha1,
 206                                struct strbuf *buf,
 207                                const char *which)
 208{
 209        strbuf_reset(buf);
 210        strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
 211                    sha1_to_hex(sha1), which);
 212        return buf->buf;
 213}
 214
 215char *sha1_pack_name(const unsigned char *sha1)
 216{
 217        static struct strbuf buf = STRBUF_INIT;
 218        return sha1_get_pack_name(sha1, &buf, "pack");
 219}
 220
 221char *sha1_pack_index_name(const unsigned char *sha1)
 222{
 223        static struct strbuf buf = STRBUF_INIT;
 224        return sha1_get_pack_name(sha1, &buf, "idx");
 225}
 226
 227struct alternate_object_database *alt_odb_list;
 228static struct alternate_object_database **alt_odb_tail;
 229
 230/*
 231 * Prepare alternate object database registry.
 232 *
 233 * The variable alt_odb_list points at the list of struct
 234 * alternate_object_database.  The elements on this list come from
 235 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 236 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 237 * whose contents is similar to that environment variable but can be
 238 * LF separated.  Its base points at a statically allocated buffer that
 239 * contains "/the/directory/corresponding/to/.git/objects/...", while
 240 * its name points just after the slash at the end of ".git/objects/"
 241 * in the example above, and has enough space to hold 40-byte hex
 242 * SHA1, an extra slash for the first level indirection, and the
 243 * terminating NUL.
 244 */
 245static int link_alt_odb_entry(const char *entry, const char *relative_base,
 246        int depth, const char *normalized_objdir)
 247{
 248        struct alternate_object_database *ent;
 249        struct alternate_object_database *alt;
 250        size_t pfxlen, entlen;
 251        struct strbuf pathbuf = STRBUF_INIT;
 252
 253        if (!is_absolute_path(entry) && relative_base) {
 254                strbuf_addstr(&pathbuf, real_path(relative_base));
 255                strbuf_addch(&pathbuf, '/');
 256        }
 257        strbuf_addstr(&pathbuf, entry);
 258
 259        normalize_path_copy(pathbuf.buf, pathbuf.buf);
 260
 261        pfxlen = strlen(pathbuf.buf);
 262
 263        /*
 264         * The trailing slash after the directory name is given by
 265         * this function at the end. Remove duplicates.
 266         */
 267        while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
 268                pfxlen -= 1;
 269
 270        entlen = st_add(pfxlen, 43); /* '/' + 2 hex + '/' + 38 hex + NUL */
 271        ent = xmalloc(st_add(sizeof(*ent), entlen));
 272        memcpy(ent->base, pathbuf.buf, pfxlen);
 273        strbuf_release(&pathbuf);
 274
 275        ent->name = ent->base + pfxlen + 1;
 276        ent->base[pfxlen + 3] = '/';
 277        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 278
 279        /* Detect cases where alternate disappeared */
 280        if (!is_directory(ent->base)) {
 281                error("object directory %s does not exist; "
 282                      "check .git/objects/info/alternates.",
 283                      ent->base);
 284                free(ent);
 285                return -1;
 286        }
 287
 288        /* Prevent the common mistake of listing the same
 289         * thing twice, or object directory itself.
 290         */
 291        for (alt = alt_odb_list; alt; alt = alt->next) {
 292                if (pfxlen == alt->name - alt->base - 1 &&
 293                    !memcmp(ent->base, alt->base, pfxlen)) {
 294                        free(ent);
 295                        return -1;
 296                }
 297        }
 298        if (!fspathcmp(ent->base, normalized_objdir)) {
 299                free(ent);
 300                return -1;
 301        }
 302
 303        /* add the alternate entry */
 304        *alt_odb_tail = ent;
 305        alt_odb_tail = &(ent->next);
 306        ent->next = NULL;
 307
 308        /* recursively add alternates */
 309        read_info_alternates(ent->base, depth + 1);
 310
 311        ent->base[pfxlen] = '/';
 312
 313        return 0;
 314}
 315
 316static void link_alt_odb_entries(const char *alt, int len, int sep,
 317                                 const char *relative_base, int depth)
 318{
 319        struct string_list entries = STRING_LIST_INIT_NODUP;
 320        char *alt_copy;
 321        int i;
 322        struct strbuf objdirbuf = STRBUF_INIT;
 323
 324        if (depth > 5) {
 325                error("%s: ignoring alternate object stores, nesting too deep.",
 326                                relative_base);
 327                return;
 328        }
 329
 330        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 331        normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
 332
 333        alt_copy = xmemdupz(alt, len);
 334        string_list_split_in_place(&entries, alt_copy, sep, -1);
 335        for (i = 0; i < entries.nr; i++) {
 336                const char *entry = entries.items[i].string;
 337                if (entry[0] == '\0' || entry[0] == '#')
 338                        continue;
 339                if (!is_absolute_path(entry) && depth) {
 340                        error("%s: ignoring relative alternate object store %s",
 341                                        relative_base, entry);
 342                } else {
 343                        link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
 344                }
 345        }
 346        string_list_clear(&entries, 0);
 347        free(alt_copy);
 348        strbuf_release(&objdirbuf);
 349}
 350
 351void read_info_alternates(const char * relative_base, int depth)
 352{
 353        char *map;
 354        size_t mapsz;
 355        struct stat st;
 356        char *path;
 357        int fd;
 358
 359        path = xstrfmt("%s/info/alternates", relative_base);
 360        fd = git_open_noatime(path);
 361        free(path);
 362        if (fd < 0)
 363                return;
 364        if (fstat(fd, &st) || (st.st_size == 0)) {
 365                close(fd);
 366                return;
 367        }
 368        mapsz = xsize_t(st.st_size);
 369        map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 370        close(fd);
 371
 372        link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
 373
 374        munmap(map, mapsz);
 375}
 376
 377void add_to_alternates_file(const char *reference)
 378{
 379        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 380        char *alts = git_pathdup("objects/info/alternates");
 381        FILE *in, *out;
 382
 383        hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
 384        out = fdopen_lock_file(lock, "w");
 385        if (!out)
 386                die_errno("unable to fdopen alternates lockfile");
 387
 388        in = fopen(alts, "r");
 389        if (in) {
 390                struct strbuf line = STRBUF_INIT;
 391                int found = 0;
 392
 393                while (strbuf_getline(&line, in) != EOF) {
 394                        if (!strcmp(reference, line.buf)) {
 395                                found = 1;
 396                                break;
 397                        }
 398                        fprintf_or_die(out, "%s\n", line.buf);
 399                }
 400
 401                strbuf_release(&line);
 402                fclose(in);
 403
 404                if (found) {
 405                        rollback_lock_file(lock);
 406                        lock = NULL;
 407                }
 408        }
 409        else if (errno != ENOENT)
 410                die_errno("unable to read alternates file");
 411
 412        if (lock) {
 413                fprintf_or_die(out, "%s\n", reference);
 414                if (commit_lock_file(lock))
 415                        die_errno("unable to move new alternates file into place");
 416                if (alt_odb_tail)
 417                        link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 418        }
 419        free(alts);
 420}
 421
 422int foreach_alt_odb(alt_odb_fn fn, void *cb)
 423{
 424        struct alternate_object_database *ent;
 425        int r = 0;
 426
 427        prepare_alt_odb();
 428        for (ent = alt_odb_list; ent; ent = ent->next) {
 429                r = fn(ent, cb);
 430                if (r)
 431                        break;
 432        }
 433        return r;
 434}
 435
 436void prepare_alt_odb(void)
 437{
 438        const char *alt;
 439
 440        if (alt_odb_tail)
 441                return;
 442
 443        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 444        if (!alt) alt = "";
 445
 446        alt_odb_tail = &alt_odb_list;
 447        link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
 448
 449        read_info_alternates(get_object_directory(), 0);
 450}
 451
 452/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 453static int freshen_file(const char *fn)
 454{
 455        struct utimbuf t;
 456        t.actime = t.modtime = time(NULL);
 457        return !utime(fn, &t);
 458}
 459
 460/*
 461 * All of the check_and_freshen functions return 1 if the file exists and was
 462 * freshened (if freshening was requested), 0 otherwise. If they return
 463 * 0, you should not assume that it is safe to skip a write of the object (it
 464 * either does not exist on disk, or has a stale mtime and may be subject to
 465 * pruning).
 466 */
 467static int check_and_freshen_file(const char *fn, int freshen)
 468{
 469        if (access(fn, F_OK))
 470                return 0;
 471        if (freshen && !freshen_file(fn))
 472                return 0;
 473        return 1;
 474}
 475
 476static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 477{
 478        return check_and_freshen_file(sha1_file_name(sha1), freshen);
 479}
 480
 481static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 482{
 483        struct alternate_object_database *alt;
 484        prepare_alt_odb();
 485        for (alt = alt_odb_list; alt; alt = alt->next) {
 486                fill_sha1_path(alt->name, sha1);
 487                if (check_and_freshen_file(alt->base, freshen))
 488                        return 1;
 489        }
 490        return 0;
 491}
 492
 493static int check_and_freshen(const unsigned char *sha1, int freshen)
 494{
 495        return check_and_freshen_local(sha1, freshen) ||
 496               check_and_freshen_nonlocal(sha1, freshen);
 497}
 498
 499int has_loose_object_nonlocal(const unsigned char *sha1)
 500{
 501        return check_and_freshen_nonlocal(sha1, 0);
 502}
 503
 504static int has_loose_object(const unsigned char *sha1)
 505{
 506        return check_and_freshen(sha1, 0);
 507}
 508
 509static unsigned int pack_used_ctr;
 510static unsigned int pack_mmap_calls;
 511static unsigned int peak_pack_open_windows;
 512static unsigned int pack_open_windows;
 513static unsigned int pack_open_fds;
 514static unsigned int pack_max_fds;
 515static size_t peak_pack_mapped;
 516static size_t pack_mapped;
 517struct packed_git *packed_git;
 518
 519static struct mru packed_git_mru_storage;
 520struct mru *packed_git_mru = &packed_git_mru_storage;
 521
 522void pack_report(void)
 523{
 524        fprintf(stderr,
 525                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 526                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 527                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 528                sz_fmt(getpagesize()),
 529                sz_fmt(packed_git_window_size),
 530                sz_fmt(packed_git_limit));
 531        fprintf(stderr,
 532                "pack_report: pack_used_ctr            = %10u\n"
 533                "pack_report: pack_mmap_calls          = %10u\n"
 534                "pack_report: pack_open_windows        = %10u / %10u\n"
 535                "pack_report: pack_mapped              = "
 536                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 537                pack_used_ctr,
 538                pack_mmap_calls,
 539                pack_open_windows, peak_pack_open_windows,
 540                sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 541}
 542
 543/*
 544 * Open and mmap the index file at path, perform a couple of
 545 * consistency checks, then record its information to p.  Return 0 on
 546 * success.
 547 */
 548static int check_packed_git_idx(const char *path, struct packed_git *p)
 549{
 550        void *idx_map;
 551        struct pack_idx_header *hdr;
 552        size_t idx_size;
 553        uint32_t version, nr, i, *index;
 554        int fd = git_open_noatime(path);
 555        struct stat st;
 556
 557        if (fd < 0)
 558                return -1;
 559        if (fstat(fd, &st)) {
 560                close(fd);
 561                return -1;
 562        }
 563        idx_size = xsize_t(st.st_size);
 564        if (idx_size < 4 * 256 + 20 + 20) {
 565                close(fd);
 566                return error("index file %s is too small", path);
 567        }
 568        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 569        close(fd);
 570
 571        hdr = idx_map;
 572        if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 573                version = ntohl(hdr->idx_version);
 574                if (version < 2 || version > 2) {
 575                        munmap(idx_map, idx_size);
 576                        return error("index file %s is version %"PRIu32
 577                                     " and is not supported by this binary"
 578                                     " (try upgrading GIT to a newer version)",
 579                                     path, version);
 580                }
 581        } else
 582                version = 1;
 583
 584        nr = 0;
 585        index = idx_map;
 586        if (version > 1)
 587                index += 2;  /* skip index header */
 588        for (i = 0; i < 256; i++) {
 589                uint32_t n = ntohl(index[i]);
 590                if (n < nr) {
 591                        munmap(idx_map, idx_size);
 592                        return error("non-monotonic index %s", path);
 593                }
 594                nr = n;
 595        }
 596
 597        if (version == 1) {
 598                /*
 599                 * Total size:
 600                 *  - 256 index entries 4 bytes each
 601                 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 602                 *  - 20-byte SHA1 of the packfile
 603                 *  - 20-byte SHA1 file checksum
 604                 */
 605                if (idx_size != 4*256 + nr * 24 + 20 + 20) {
 606                        munmap(idx_map, idx_size);
 607                        return error("wrong index v1 file size in %s", path);
 608                }
 609        } else if (version == 2) {
 610                /*
 611                 * Minimum size:
 612                 *  - 8 bytes of header
 613                 *  - 256 index entries 4 bytes each
 614                 *  - 20-byte sha1 entry * nr
 615                 *  - 4-byte crc entry * nr
 616                 *  - 4-byte offset entry * nr
 617                 *  - 20-byte SHA1 of the packfile
 618                 *  - 20-byte SHA1 file checksum
 619                 * And after the 4-byte offset table might be a
 620                 * variable sized table containing 8-byte entries
 621                 * for offsets larger than 2^31.
 622                 */
 623                unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
 624                unsigned long max_size = min_size;
 625                if (nr)
 626                        max_size += (nr - 1)*8;
 627                if (idx_size < min_size || idx_size > max_size) {
 628                        munmap(idx_map, idx_size);
 629                        return error("wrong index v2 file size in %s", path);
 630                }
 631                if (idx_size != min_size &&
 632                    /*
 633                     * make sure we can deal with large pack offsets.
 634                     * 31-bit signed offset won't be enough, neither
 635                     * 32-bit unsigned one will be.
 636                     */
 637                    (sizeof(off_t) <= 4)) {
 638                        munmap(idx_map, idx_size);
 639                        return error("pack too large for current definition of off_t in %s", path);
 640                }
 641        }
 642
 643        p->index_version = version;
 644        p->index_data = idx_map;
 645        p->index_size = idx_size;
 646        p->num_objects = nr;
 647        return 0;
 648}
 649
 650int open_pack_index(struct packed_git *p)
 651{
 652        char *idx_name;
 653        size_t len;
 654        int ret;
 655
 656        if (p->index_data)
 657                return 0;
 658
 659        if (!strip_suffix(p->pack_name, ".pack", &len))
 660                die("BUG: pack_name does not end in .pack");
 661        idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 662        ret = check_packed_git_idx(idx_name, p);
 663        free(idx_name);
 664        return ret;
 665}
 666
 667static void scan_windows(struct packed_git *p,
 668        struct packed_git **lru_p,
 669        struct pack_window **lru_w,
 670        struct pack_window **lru_l)
 671{
 672        struct pack_window *w, *w_l;
 673
 674        for (w_l = NULL, w = p->windows; w; w = w->next) {
 675                if (!w->inuse_cnt) {
 676                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 677                                *lru_p = p;
 678                                *lru_w = w;
 679                                *lru_l = w_l;
 680                        }
 681                }
 682                w_l = w;
 683        }
 684}
 685
 686static int unuse_one_window(struct packed_git *current)
 687{
 688        struct packed_git *p, *lru_p = NULL;
 689        struct pack_window *lru_w = NULL, *lru_l = NULL;
 690
 691        if (current)
 692                scan_windows(current, &lru_p, &lru_w, &lru_l);
 693        for (p = packed_git; p; p = p->next)
 694                scan_windows(p, &lru_p, &lru_w, &lru_l);
 695        if (lru_p) {
 696                munmap(lru_w->base, lru_w->len);
 697                pack_mapped -= lru_w->len;
 698                if (lru_l)
 699                        lru_l->next = lru_w->next;
 700                else
 701                        lru_p->windows = lru_w->next;
 702                free(lru_w);
 703                pack_open_windows--;
 704                return 1;
 705        }
 706        return 0;
 707}
 708
 709void release_pack_memory(size_t need)
 710{
 711        size_t cur = pack_mapped;
 712        while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 713                ; /* nothing */
 714}
 715
 716static void mmap_limit_check(size_t length)
 717{
 718        static size_t limit = 0;
 719        if (!limit) {
 720                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 721                if (!limit)
 722                        limit = SIZE_MAX;
 723        }
 724        if (length > limit)
 725                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 726                    (uintmax_t)length, (uintmax_t)limit);
 727}
 728
 729void *xmmap_gently(void *start, size_t length,
 730                  int prot, int flags, int fd, off_t offset)
 731{
 732        void *ret;
 733
 734        mmap_limit_check(length);
 735        ret = mmap(start, length, prot, flags, fd, offset);
 736        if (ret == MAP_FAILED) {
 737                if (!length)
 738                        return NULL;
 739                release_pack_memory(length);
 740                ret = mmap(start, length, prot, flags, fd, offset);
 741        }
 742        return ret;
 743}
 744
 745void *xmmap(void *start, size_t length,
 746        int prot, int flags, int fd, off_t offset)
 747{
 748        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 749        if (ret == MAP_FAILED)
 750                die_errno("mmap failed");
 751        return ret;
 752}
 753
 754void close_pack_windows(struct packed_git *p)
 755{
 756        while (p->windows) {
 757                struct pack_window *w = p->windows;
 758
 759                if (w->inuse_cnt)
 760                        die("pack '%s' still has open windows to it",
 761                            p->pack_name);
 762                munmap(w->base, w->len);
 763                pack_mapped -= w->len;
 764                pack_open_windows--;
 765                p->windows = w->next;
 766                free(w);
 767        }
 768}
 769
 770static int close_pack_fd(struct packed_git *p)
 771{
 772        if (p->pack_fd < 0)
 773                return 0;
 774
 775        close(p->pack_fd);
 776        pack_open_fds--;
 777        p->pack_fd = -1;
 778
 779        return 1;
 780}
 781
 782static void close_pack(struct packed_git *p)
 783{
 784        close_pack_windows(p);
 785        close_pack_fd(p);
 786        close_pack_index(p);
 787}
 788
 789void close_all_packs(void)
 790{
 791        struct packed_git *p;
 792
 793        for (p = packed_git; p; p = p->next)
 794                if (p->do_not_close)
 795                        die("BUG: want to close pack marked 'do-not-close'");
 796                else
 797                        close_pack(p);
 798}
 799
 800
 801/*
 802 * The LRU pack is the one with the oldest MRU window, preferring packs
 803 * with no used windows, or the oldest mtime if it has no windows allocated.
 804 */
 805static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 806{
 807        struct pack_window *w, *this_mru_w;
 808        int has_windows_inuse = 0;
 809
 810        /*
 811         * Reject this pack if it has windows and the previously selected
 812         * one does not.  If this pack does not have windows, reject
 813         * it if the pack file is newer than the previously selected one.
 814         */
 815        if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 816                return;
 817
 818        for (w = this_mru_w = p->windows; w; w = w->next) {
 819                /*
 820                 * Reject this pack if any of its windows are in use,
 821                 * but the previously selected pack did not have any
 822                 * inuse windows.  Otherwise, record that this pack
 823                 * has windows in use.
 824                 */
 825                if (w->inuse_cnt) {
 826                        if (*accept_windows_inuse)
 827                                has_windows_inuse = 1;
 828                        else
 829                                return;
 830                }
 831
 832                if (w->last_used > this_mru_w->last_used)
 833                        this_mru_w = w;
 834
 835                /*
 836                 * Reject this pack if it has windows that have been
 837                 * used more recently than the previously selected pack.
 838                 * If the previously selected pack had windows inuse and
 839                 * we have not encountered a window in this pack that is
 840                 * inuse, skip this check since we prefer a pack with no
 841                 * inuse windows to one that has inuse windows.
 842                 */
 843                if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 844                    this_mru_w->last_used > (*mru_w)->last_used)
 845                        return;
 846        }
 847
 848        /*
 849         * Select this pack.
 850         */
 851        *mru_w = this_mru_w;
 852        *lru_p = p;
 853        *accept_windows_inuse = has_windows_inuse;
 854}
 855
 856static int close_one_pack(void)
 857{
 858        struct packed_git *p, *lru_p = NULL;
 859        struct pack_window *mru_w = NULL;
 860        int accept_windows_inuse = 1;
 861
 862        for (p = packed_git; p; p = p->next) {
 863                if (p->pack_fd == -1)
 864                        continue;
 865                find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 866        }
 867
 868        if (lru_p)
 869                return close_pack_fd(lru_p);
 870
 871        return 0;
 872}
 873
 874void unuse_pack(struct pack_window **w_cursor)
 875{
 876        struct pack_window *w = *w_cursor;
 877        if (w) {
 878                w->inuse_cnt--;
 879                *w_cursor = NULL;
 880        }
 881}
 882
 883void close_pack_index(struct packed_git *p)
 884{
 885        if (p->index_data) {
 886                munmap((void *)p->index_data, p->index_size);
 887                p->index_data = NULL;
 888        }
 889}
 890
 891static unsigned int get_max_fd_limit(void)
 892{
 893#ifdef RLIMIT_NOFILE
 894        {
 895                struct rlimit lim;
 896
 897                if (!getrlimit(RLIMIT_NOFILE, &lim))
 898                        return lim.rlim_cur;
 899        }
 900#endif
 901
 902#ifdef _SC_OPEN_MAX
 903        {
 904                long open_max = sysconf(_SC_OPEN_MAX);
 905                if (0 < open_max)
 906                        return open_max;
 907                /*
 908                 * Otherwise, we got -1 for one of the two
 909                 * reasons:
 910                 *
 911                 * (1) sysconf() did not understand _SC_OPEN_MAX
 912                 *     and signaled an error with -1; or
 913                 * (2) sysconf() said there is no limit.
 914                 *
 915                 * We _could_ clear errno before calling sysconf() to
 916                 * tell these two cases apart and return a huge number
 917                 * in the latter case to let the caller cap it to a
 918                 * value that is not so selfish, but letting the
 919                 * fallback OPEN_MAX codepath take care of these cases
 920                 * is a lot simpler.
 921                 */
 922        }
 923#endif
 924
 925#ifdef OPEN_MAX
 926        return OPEN_MAX;
 927#else
 928        return 1; /* see the caller ;-) */
 929#endif
 930}
 931
 932/*
 933 * Do not call this directly as this leaks p->pack_fd on error return;
 934 * call open_packed_git() instead.
 935 */
 936static int open_packed_git_1(struct packed_git *p)
 937{
 938        struct stat st;
 939        struct pack_header hdr;
 940        unsigned char sha1[20];
 941        unsigned char *idx_sha1;
 942        long fd_flag;
 943
 944        if (!p->index_data && open_pack_index(p))
 945                return error("packfile %s index unavailable", p->pack_name);
 946
 947        if (!pack_max_fds) {
 948                unsigned int max_fds = get_max_fd_limit();
 949
 950                /* Save 3 for stdin/stdout/stderr, 22 for work */
 951                if (25 < max_fds)
 952                        pack_max_fds = max_fds - 25;
 953                else
 954                        pack_max_fds = 1;
 955        }
 956
 957        while (pack_max_fds <= pack_open_fds && close_one_pack())
 958                ; /* nothing */
 959
 960        p->pack_fd = git_open_noatime(p->pack_name);
 961        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 962                return -1;
 963        pack_open_fds++;
 964
 965        /* If we created the struct before we had the pack we lack size. */
 966        if (!p->pack_size) {
 967                if (!S_ISREG(st.st_mode))
 968                        return error("packfile %s not a regular file", p->pack_name);
 969                p->pack_size = st.st_size;
 970        } else if (p->pack_size != st.st_size)
 971                return error("packfile %s size changed", p->pack_name);
 972
 973        /* We leave these file descriptors open with sliding mmap;
 974         * there is no point keeping them open across exec(), though.
 975         */
 976        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 977        if (fd_flag < 0)
 978                return error("cannot determine file descriptor flags");
 979        fd_flag |= FD_CLOEXEC;
 980        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 981                return error("cannot set FD_CLOEXEC");
 982
 983        /* Verify we recognize this pack file format. */
 984        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 985                return error("file %s is far too short to be a packfile", p->pack_name);
 986        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 987                return error("file %s is not a GIT packfile", p->pack_name);
 988        if (!pack_version_ok(hdr.hdr_version))
 989                return error("packfile %s is version %"PRIu32" and not"
 990                        " supported (try upgrading GIT to a newer version)",
 991                        p->pack_name, ntohl(hdr.hdr_version));
 992
 993        /* Verify the pack matches its index. */
 994        if (p->num_objects != ntohl(hdr.hdr_entries))
 995                return error("packfile %s claims to have %"PRIu32" objects"
 996                             " while index indicates %"PRIu32" objects",
 997                             p->pack_name, ntohl(hdr.hdr_entries),
 998                             p->num_objects);
 999        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
1000                return error("end of packfile %s is unavailable", p->pack_name);
1001        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
1002                return error("packfile %s signature is unavailable", p->pack_name);
1003        idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
1004        if (hashcmp(sha1, idx_sha1))
1005                return error("packfile %s does not match index", p->pack_name);
1006        return 0;
1007}
1008
1009static int open_packed_git(struct packed_git *p)
1010{
1011        if (!open_packed_git_1(p))
1012                return 0;
1013        close_pack_fd(p);
1014        return -1;
1015}
1016
1017static int in_window(struct pack_window *win, off_t offset)
1018{
1019        /* We must promise at least 20 bytes (one hash) after the
1020         * offset is available from this window, otherwise the offset
1021         * is not actually in this window and a different window (which
1022         * has that one hash excess) must be used.  This is to support
1023         * the object header and delta base parsing routines below.
1024         */
1025        off_t win_off = win->offset;
1026        return win_off <= offset
1027                && (offset + 20) <= (win_off + win->len);
1028}
1029
1030unsigned char *use_pack(struct packed_git *p,
1031                struct pack_window **w_cursor,
1032                off_t offset,
1033                unsigned long *left)
1034{
1035        struct pack_window *win = *w_cursor;
1036
1037        /* Since packfiles end in a hash of their content and it's
1038         * pointless to ask for an offset into the middle of that
1039         * hash, and the in_window function above wouldn't match
1040         * don't allow an offset too close to the end of the file.
1041         */
1042        if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
1043                die("packfile %s cannot be accessed", p->pack_name);
1044        if (offset > (p->pack_size - 20))
1045                die("offset beyond end of packfile (truncated pack?)");
1046        if (offset < 0)
1047                die(_("offset before end of packfile (broken .idx?)"));
1048
1049        if (!win || !in_window(win, offset)) {
1050                if (win)
1051                        win->inuse_cnt--;
1052                for (win = p->windows; win; win = win->next) {
1053                        if (in_window(win, offset))
1054                                break;
1055                }
1056                if (!win) {
1057                        size_t window_align = packed_git_window_size / 2;
1058                        off_t len;
1059
1060                        if (p->pack_fd == -1 && open_packed_git(p))
1061                                die("packfile %s cannot be accessed", p->pack_name);
1062
1063                        win = xcalloc(1, sizeof(*win));
1064                        win->offset = (offset / window_align) * window_align;
1065                        len = p->pack_size - win->offset;
1066                        if (len > packed_git_window_size)
1067                                len = packed_git_window_size;
1068                        win->len = (size_t)len;
1069                        pack_mapped += win->len;
1070                        while (packed_git_limit < pack_mapped
1071                                && unuse_one_window(p))
1072                                ; /* nothing */
1073                        win->base = xmmap(NULL, win->len,
1074                                PROT_READ, MAP_PRIVATE,
1075                                p->pack_fd, win->offset);
1076                        if (win->base == MAP_FAILED)
1077                                die_errno("packfile %s cannot be mapped",
1078                                          p->pack_name);
1079                        if (!win->offset && win->len == p->pack_size
1080                                && !p->do_not_close)
1081                                close_pack_fd(p);
1082                        pack_mmap_calls++;
1083                        pack_open_windows++;
1084                        if (pack_mapped > peak_pack_mapped)
1085                                peak_pack_mapped = pack_mapped;
1086                        if (pack_open_windows > peak_pack_open_windows)
1087                                peak_pack_open_windows = pack_open_windows;
1088                        win->next = p->windows;
1089                        p->windows = win;
1090                }
1091        }
1092        if (win != *w_cursor) {
1093                win->last_used = pack_used_ctr++;
1094                win->inuse_cnt++;
1095                *w_cursor = win;
1096        }
1097        offset -= win->offset;
1098        if (left)
1099                *left = win->len - xsize_t(offset);
1100        return win->base + offset;
1101}
1102
1103static struct packed_git *alloc_packed_git(int extra)
1104{
1105        struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
1106        memset(p, 0, sizeof(*p));
1107        p->pack_fd = -1;
1108        return p;
1109}
1110
1111static void try_to_free_pack_memory(size_t size)
1112{
1113        release_pack_memory(size);
1114}
1115
1116struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
1117{
1118        static int have_set_try_to_free_routine;
1119        struct stat st;
1120        size_t alloc;
1121        struct packed_git *p;
1122
1123        if (!have_set_try_to_free_routine) {
1124                have_set_try_to_free_routine = 1;
1125                set_try_to_free_routine(try_to_free_pack_memory);
1126        }
1127
1128        /*
1129         * Make sure a corresponding .pack file exists and that
1130         * the index looks sane.
1131         */
1132        if (!strip_suffix_mem(path, &path_len, ".idx"))
1133                return NULL;
1134
1135        /*
1136         * ".pack" is long enough to hold any suffix we're adding (and
1137         * the use xsnprintf double-checks that)
1138         */
1139        alloc = st_add3(path_len, strlen(".pack"), 1);
1140        p = alloc_packed_git(alloc);
1141        memcpy(p->pack_name, path, path_len);
1142
1143        xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
1144        if (!access(p->pack_name, F_OK))
1145                p->pack_keep = 1;
1146
1147        xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
1148        if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
1149                free(p);
1150                return NULL;
1151        }
1152
1153        /* ok, it looks sane as far as we can check without
1154         * actually mapping the pack file.
1155         */
1156        p->pack_size = st.st_size;
1157        p->pack_local = local;
1158        p->mtime = st.st_mtime;
1159        if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
1160                hashclr(p->sha1);
1161        return p;
1162}
1163
1164struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
1165{
1166        const char *path = sha1_pack_name(sha1);
1167        size_t alloc = st_add(strlen(path), 1);
1168        struct packed_git *p = alloc_packed_git(alloc);
1169
1170        memcpy(p->pack_name, path, alloc); /* includes NUL */
1171        hashcpy(p->sha1, sha1);
1172        if (check_packed_git_idx(idx_path, p)) {
1173                free(p);
1174                return NULL;
1175        }
1176
1177        return p;
1178}
1179
1180void install_packed_git(struct packed_git *pack)
1181{
1182        if (pack->pack_fd != -1)
1183                pack_open_fds++;
1184
1185        pack->next = packed_git;
1186        packed_git = pack;
1187}
1188
1189void (*report_garbage)(unsigned seen_bits, const char *path);
1190
1191static void report_helper(const struct string_list *list,
1192                          int seen_bits, int first, int last)
1193{
1194        if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
1195                return;
1196
1197        for (; first < last; first++)
1198                report_garbage(seen_bits, list->items[first].string);
1199}
1200
1201static void report_pack_garbage(struct string_list *list)
1202{
1203        int i, baselen = -1, first = 0, seen_bits = 0;
1204
1205        if (!report_garbage)
1206                return;
1207
1208        string_list_sort(list);
1209
1210        for (i = 0; i < list->nr; i++) {
1211                const char *path = list->items[i].string;
1212                if (baselen != -1 &&
1213                    strncmp(path, list->items[first].string, baselen)) {
1214                        report_helper(list, seen_bits, first, i);
1215                        baselen = -1;
1216                        seen_bits = 0;
1217                }
1218                if (baselen == -1) {
1219                        const char *dot = strrchr(path, '.');
1220                        if (!dot) {
1221                                report_garbage(PACKDIR_FILE_GARBAGE, path);
1222                                continue;
1223                        }
1224                        baselen = dot - path + 1;
1225                        first = i;
1226                }
1227                if (!strcmp(path + baselen, "pack"))
1228                        seen_bits |= 1;
1229                else if (!strcmp(path + baselen, "idx"))
1230                        seen_bits |= 2;
1231        }
1232        report_helper(list, seen_bits, first, list->nr);
1233}
1234
1235static void prepare_packed_git_one(char *objdir, int local)
1236{
1237        struct strbuf path = STRBUF_INIT;
1238        size_t dirnamelen;
1239        DIR *dir;
1240        struct dirent *de;
1241        struct string_list garbage = STRING_LIST_INIT_DUP;
1242
1243        strbuf_addstr(&path, objdir);
1244        strbuf_addstr(&path, "/pack");
1245        dir = opendir(path.buf);
1246        if (!dir) {
1247                if (errno != ENOENT)
1248                        error_errno("unable to open object pack directory: %s",
1249                                    path.buf);
1250                strbuf_release(&path);
1251                return;
1252        }
1253        strbuf_addch(&path, '/');
1254        dirnamelen = path.len;
1255        while ((de = readdir(dir)) != NULL) {
1256                struct packed_git *p;
1257                size_t base_len;
1258
1259                if (is_dot_or_dotdot(de->d_name))
1260                        continue;
1261
1262                strbuf_setlen(&path, dirnamelen);
1263                strbuf_addstr(&path, de->d_name);
1264
1265                base_len = path.len;
1266                if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
1267                        /* Don't reopen a pack we already have. */
1268                        for (p = packed_git; p; p = p->next) {
1269                                size_t len;
1270                                if (strip_suffix(p->pack_name, ".pack", &len) &&
1271                                    len == base_len &&
1272                                    !memcmp(p->pack_name, path.buf, len))
1273                                        break;
1274                        }
1275                        if (p == NULL &&
1276                            /*
1277                             * See if it really is a valid .idx file with
1278                             * corresponding .pack file that we can map.
1279                             */
1280                            (p = add_packed_git(path.buf, path.len, local)) != NULL)
1281                                install_packed_git(p);
1282                }
1283
1284                if (!report_garbage)
1285                        continue;
1286
1287                if (ends_with(de->d_name, ".idx") ||
1288                    ends_with(de->d_name, ".pack") ||
1289                    ends_with(de->d_name, ".bitmap") ||
1290                    ends_with(de->d_name, ".keep"))
1291                        string_list_append(&garbage, path.buf);
1292                else
1293                        report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
1294        }
1295        closedir(dir);
1296        report_pack_garbage(&garbage);
1297        string_list_clear(&garbage, 0);
1298        strbuf_release(&path);
1299}
1300
1301static int sort_pack(const void *a_, const void *b_)
1302{
1303        struct packed_git *a = *((struct packed_git **)a_);
1304        struct packed_git *b = *((struct packed_git **)b_);
1305        int st;
1306
1307        /*
1308         * Local packs tend to contain objects specific to our
1309         * variant of the project than remote ones.  In addition,
1310         * remote ones could be on a network mounted filesystem.
1311         * Favor local ones for these reasons.
1312         */
1313        st = a->pack_local - b->pack_local;
1314        if (st)
1315                return -st;
1316
1317        /*
1318         * Younger packs tend to contain more recent objects,
1319         * and more recent objects tend to get accessed more
1320         * often.
1321         */
1322        if (a->mtime < b->mtime)
1323                return 1;
1324        else if (a->mtime == b->mtime)
1325                return 0;
1326        return -1;
1327}
1328
1329static void rearrange_packed_git(void)
1330{
1331        struct packed_git **ary, *p;
1332        int i, n;
1333
1334        for (n = 0, p = packed_git; p; p = p->next)
1335                n++;
1336        if (n < 2)
1337                return;
1338
1339        /* prepare an array of packed_git for easier sorting */
1340        ary = xcalloc(n, sizeof(struct packed_git *));
1341        for (n = 0, p = packed_git; p; p = p->next)
1342                ary[n++] = p;
1343
1344        qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1345
1346        /* link them back again */
1347        for (i = 0; i < n - 1; i++)
1348                ary[i]->next = ary[i + 1];
1349        ary[n - 1]->next = NULL;
1350        packed_git = ary[0];
1351
1352        free(ary);
1353}
1354
1355static void prepare_packed_git_mru(void)
1356{
1357        struct packed_git *p;
1358
1359        mru_clear(packed_git_mru);
1360        for (p = packed_git; p; p = p->next)
1361                mru_append(packed_git_mru, p);
1362}
1363
1364static int prepare_packed_git_run_once = 0;
1365void prepare_packed_git(void)
1366{
1367        struct alternate_object_database *alt;
1368
1369        if (prepare_packed_git_run_once)
1370                return;
1371        prepare_packed_git_one(get_object_directory(), 1);
1372        prepare_alt_odb();
1373        for (alt = alt_odb_list; alt; alt = alt->next) {
1374                alt->name[-1] = 0;
1375                prepare_packed_git_one(alt->base, 0);
1376                alt->name[-1] = '/';
1377        }
1378        rearrange_packed_git();
1379        prepare_packed_git_mru();
1380        prepare_packed_git_run_once = 1;
1381}
1382
1383void reprepare_packed_git(void)
1384{
1385        prepare_packed_git_run_once = 0;
1386        prepare_packed_git();
1387}
1388
1389static void mark_bad_packed_object(struct packed_git *p,
1390                                   const unsigned char *sha1)
1391{
1392        unsigned i;
1393        for (i = 0; i < p->num_bad_objects; i++)
1394                if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1395                        return;
1396        p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1397                                      st_mult(GIT_SHA1_RAWSZ,
1398                                              st_add(p->num_bad_objects, 1)));
1399        hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1400        p->num_bad_objects++;
1401}
1402
1403static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1404{
1405        struct packed_git *p;
1406        unsigned i;
1407
1408        for (p = packed_git; p; p = p->next)
1409                for (i = 0; i < p->num_bad_objects; i++)
1410                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1411                                return p;
1412        return NULL;
1413}
1414
1415/*
1416 * With an in-core object data in "map", rehash it to make sure the
1417 * object name actually matches "sha1" to detect object corruption.
1418 * With "map" == NULL, try reading the object named with "sha1" using
1419 * the streaming interface and rehash it to do the same.
1420 */
1421int check_sha1_signature(const unsigned char *sha1, void *map,
1422                         unsigned long size, const char *type)
1423{
1424        unsigned char real_sha1[20];
1425        enum object_type obj_type;
1426        struct git_istream *st;
1427        git_SHA_CTX c;
1428        char hdr[32];
1429        int hdrlen;
1430
1431        if (map) {
1432                hash_sha1_file(map, size, type, real_sha1);
1433                return hashcmp(sha1, real_sha1) ? -1 : 0;
1434        }
1435
1436        st = open_istream(sha1, &obj_type, &size, NULL);
1437        if (!st)
1438                return -1;
1439
1440        /* Generate the header */
1441        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
1442
1443        /* Sha1.. */
1444        git_SHA1_Init(&c);
1445        git_SHA1_Update(&c, hdr, hdrlen);
1446        for (;;) {
1447                char buf[1024 * 16];
1448                ssize_t readlen = read_istream(st, buf, sizeof(buf));
1449
1450                if (readlen < 0) {
1451                        close_istream(st);
1452                        return -1;
1453                }
1454                if (!readlen)
1455                        break;
1456                git_SHA1_Update(&c, buf, readlen);
1457        }
1458        git_SHA1_Final(real_sha1, &c);
1459        close_istream(st);
1460        return hashcmp(sha1, real_sha1) ? -1 : 0;
1461}
1462
1463int git_open_noatime(const char *name)
1464{
1465        static int sha1_file_open_flag = O_NOATIME;
1466
1467        for (;;) {
1468                int fd;
1469
1470                errno = 0;
1471                fd = open(name, O_RDONLY | sha1_file_open_flag);
1472                if (fd >= 0)
1473                        return fd;
1474
1475                /* Might the failure be due to O_NOATIME? */
1476                if (errno != ENOENT && sha1_file_open_flag) {
1477                        sha1_file_open_flag = 0;
1478                        continue;
1479                }
1480
1481                return -1;
1482        }
1483}
1484
1485static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
1486{
1487        struct alternate_object_database *alt;
1488
1489        if (!lstat(sha1_file_name(sha1), st))
1490                return 0;
1491
1492        prepare_alt_odb();
1493        errno = ENOENT;
1494        for (alt = alt_odb_list; alt; alt = alt->next) {
1495                fill_sha1_path(alt->name, sha1);
1496                if (!lstat(alt->base, st))
1497                        return 0;
1498        }
1499
1500        return -1;
1501}
1502
1503static int open_sha1_file(const unsigned char *sha1)
1504{
1505        int fd;
1506        struct alternate_object_database *alt;
1507        int most_interesting_errno;
1508
1509        fd = git_open_noatime(sha1_file_name(sha1));
1510        if (fd >= 0)
1511                return fd;
1512        most_interesting_errno = errno;
1513
1514        prepare_alt_odb();
1515        for (alt = alt_odb_list; alt; alt = alt->next) {
1516                fill_sha1_path(alt->name, sha1);
1517                fd = git_open_noatime(alt->base);
1518                if (fd >= 0)
1519                        return fd;
1520                if (most_interesting_errno == ENOENT)
1521                        most_interesting_errno = errno;
1522        }
1523        errno = most_interesting_errno;
1524        return -1;
1525}
1526
1527void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1528{
1529        void *map;
1530        int fd;
1531
1532        fd = open_sha1_file(sha1);
1533        map = NULL;
1534        if (fd >= 0) {
1535                struct stat st;
1536
1537                if (!fstat(fd, &st)) {
1538                        *size = xsize_t(st.st_size);
1539                        if (!*size) {
1540                                /* mmap() is forbidden on empty files */
1541                                error("object file %s is empty", sha1_file_name(sha1));
1542                                return NULL;
1543                        }
1544                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1545                }
1546                close(fd);
1547        }
1548        return map;
1549}
1550
1551unsigned long unpack_object_header_buffer(const unsigned char *buf,
1552                unsigned long len, enum object_type *type, unsigned long *sizep)
1553{
1554        unsigned shift;
1555        unsigned long size, c;
1556        unsigned long used = 0;
1557
1558        c = buf[used++];
1559        *type = (c >> 4) & 7;
1560        size = c & 15;
1561        shift = 4;
1562        while (c & 0x80) {
1563                if (len <= used || bitsizeof(long) <= shift) {
1564                        error("bad object header");
1565                        size = used = 0;
1566                        break;
1567                }
1568                c = buf[used++];
1569                size += (c & 0x7f) << shift;
1570                shift += 7;
1571        }
1572        *sizep = size;
1573        return used;
1574}
1575
1576int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1577{
1578        /* Get the data stream */
1579        memset(stream, 0, sizeof(*stream));
1580        stream->next_in = map;
1581        stream->avail_in = mapsize;
1582        stream->next_out = buffer;
1583        stream->avail_out = bufsiz;
1584
1585        git_inflate_init(stream);
1586        return git_inflate(stream, 0);
1587}
1588
1589static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
1590                                        unsigned long mapsize, void *buffer,
1591                                        unsigned long bufsiz, struct strbuf *header)
1592{
1593        int status;
1594
1595        status = unpack_sha1_header(stream, map, mapsize, buffer, bufsiz);
1596
1597        /*
1598         * Check if entire header is unpacked in the first iteration.
1599         */
1600        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1601                return 0;
1602
1603        /*
1604         * buffer[0..bufsiz] was not large enough.  Copy the partial
1605         * result out to header, and then append the result of further
1606         * reading the stream.
1607         */
1608        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1609        stream->next_out = buffer;
1610        stream->avail_out = bufsiz;
1611
1612        do {
1613                status = git_inflate(stream, 0);
1614                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1615                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1616                        return 0;
1617                stream->next_out = buffer;
1618                stream->avail_out = bufsiz;
1619        } while (status != Z_STREAM_END);
1620        return -1;
1621}
1622
1623static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1624{
1625        int bytes = strlen(buffer) + 1;
1626        unsigned char *buf = xmallocz(size);
1627        unsigned long n;
1628        int status = Z_OK;
1629
1630        n = stream->total_out - bytes;
1631        if (n > size)
1632                n = size;
1633        memcpy(buf, (char *) buffer + bytes, n);
1634        bytes = n;
1635        if (bytes <= size) {
1636                /*
1637                 * The above condition must be (bytes <= size), not
1638                 * (bytes < size).  In other words, even though we
1639                 * expect no more output and set avail_out to zero,
1640                 * the input zlib stream may have bytes that express
1641                 * "this concludes the stream", and we *do* want to
1642                 * eat that input.
1643                 *
1644                 * Otherwise we would not be able to test that we
1645                 * consumed all the input to reach the expected size;
1646                 * we also want to check that zlib tells us that all
1647                 * went well with status == Z_STREAM_END at the end.
1648                 */
1649                stream->next_out = buf + bytes;
1650                stream->avail_out = size - bytes;
1651                while (status == Z_OK)
1652                        status = git_inflate(stream, Z_FINISH);
1653        }
1654        if (status == Z_STREAM_END && !stream->avail_in) {
1655                git_inflate_end(stream);
1656                return buf;
1657        }
1658
1659        if (status < 0)
1660                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1661        else if (stream->avail_in)
1662                error("garbage at end of loose object '%s'",
1663                      sha1_to_hex(sha1));
1664        free(buf);
1665        return NULL;
1666}
1667
1668/*
1669 * We used to just use "sscanf()", but that's actually way
1670 * too permissive for what we want to check. So do an anal
1671 * object header parse by hand.
1672 */
1673static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1674                               unsigned int flags)
1675{
1676        const char *type_buf = hdr;
1677        unsigned long size;
1678        int type, type_len = 0;
1679
1680        /*
1681         * The type can be of any size but is followed by
1682         * a space.
1683         */
1684        for (;;) {
1685                char c = *hdr++;
1686                if (c == ' ')
1687                        break;
1688                type_len++;
1689        }
1690
1691        type = type_from_string_gently(type_buf, type_len, 1);
1692        if (oi->typename)
1693                strbuf_add(oi->typename, type_buf, type_len);
1694        /*
1695         * Set type to 0 if its an unknown object and
1696         * we're obtaining the type using '--allow-unknown-type'
1697         * option.
1698         */
1699        if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
1700                type = 0;
1701        else if (type < 0)
1702                die("invalid object type");
1703        if (oi->typep)
1704                *oi->typep = type;
1705
1706        /*
1707         * The length must follow immediately, and be in canonical
1708         * decimal format (ie "010" is not valid).
1709         */
1710        size = *hdr++ - '0';
1711        if (size > 9)
1712                return -1;
1713        if (size) {
1714                for (;;) {
1715                        unsigned long c = *hdr - '0';
1716                        if (c > 9)
1717                                break;
1718                        hdr++;
1719                        size = size * 10 + c;
1720                }
1721        }
1722
1723        if (oi->sizep)
1724                *oi->sizep = size;
1725
1726        /*
1727         * The length must be followed by a zero byte
1728         */
1729        return *hdr ? -1 : type;
1730}
1731
1732int parse_sha1_header(const char *hdr, unsigned long *sizep)
1733{
1734        struct object_info oi;
1735
1736        oi.sizep = sizep;
1737        oi.typename = NULL;
1738        oi.typep = NULL;
1739        return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
1740}
1741
1742static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1743{
1744        int ret;
1745        git_zstream stream;
1746        char hdr[8192];
1747
1748        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1749        if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1750                return NULL;
1751
1752        return unpack_sha1_rest(&stream, hdr, *size, sha1);
1753}
1754
1755unsigned long get_size_from_delta(struct packed_git *p,
1756                                  struct pack_window **w_curs,
1757                                  off_t curpos)
1758{
1759        const unsigned char *data;
1760        unsigned char delta_head[20], *in;
1761        git_zstream stream;
1762        int st;
1763
1764        memset(&stream, 0, sizeof(stream));
1765        stream.next_out = delta_head;
1766        stream.avail_out = sizeof(delta_head);
1767
1768        git_inflate_init(&stream);
1769        do {
1770                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1771                stream.next_in = in;
1772                st = git_inflate(&stream, Z_FINISH);
1773                curpos += stream.next_in - in;
1774        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1775                 stream.total_out < sizeof(delta_head));
1776        git_inflate_end(&stream);
1777        if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1778                error("delta data unpack-initial failed");
1779                return 0;
1780        }
1781
1782        /* Examine the initial part of the delta to figure out
1783         * the result size.
1784         */
1785        data = delta_head;
1786
1787        /* ignore base size */
1788        get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1789
1790        /* Read the result size */
1791        return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1792}
1793
1794static off_t get_delta_base(struct packed_git *p,
1795                                    struct pack_window **w_curs,
1796                                    off_t *curpos,
1797                                    enum object_type type,
1798                                    off_t delta_obj_offset)
1799{
1800        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1801        off_t base_offset;
1802
1803        /* use_pack() assured us we have [base_info, base_info + 20)
1804         * as a range that we can look at without walking off the
1805         * end of the mapped window.  Its actually the hash size
1806         * that is assured.  An OFS_DELTA longer than the hash size
1807         * is stupid, as then a REF_DELTA would be smaller to store.
1808         */
1809        if (type == OBJ_OFS_DELTA) {
1810                unsigned used = 0;
1811                unsigned char c = base_info[used++];
1812                base_offset = c & 127;
1813                while (c & 128) {
1814                        base_offset += 1;
1815                        if (!base_offset || MSB(base_offset, 7))
1816                                return 0;  /* overflow */
1817                        c = base_info[used++];
1818                        base_offset = (base_offset << 7) + (c & 127);
1819                }
1820                base_offset = delta_obj_offset - base_offset;
1821                if (base_offset <= 0 || base_offset >= delta_obj_offset)
1822                        return 0;  /* out of bound */
1823                *curpos += used;
1824        } else if (type == OBJ_REF_DELTA) {
1825                /* The base entry _must_ be in the same pack */
1826                base_offset = find_pack_entry_one(base_info, p);
1827                *curpos += 20;
1828        } else
1829                die("I am totally screwed");
1830        return base_offset;
1831}
1832
1833/*
1834 * Like get_delta_base above, but we return the sha1 instead of the pack
1835 * offset. This means it is cheaper for REF deltas (we do not have to do
1836 * the final object lookup), but more expensive for OFS deltas (we
1837 * have to load the revidx to convert the offset back into a sha1).
1838 */
1839static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1840                                                struct pack_window **w_curs,
1841                                                off_t curpos,
1842                                                enum object_type type,
1843                                                off_t delta_obj_offset)
1844{
1845        if (type == OBJ_REF_DELTA) {
1846                unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1847                return base;
1848        } else if (type == OBJ_OFS_DELTA) {
1849                struct revindex_entry *revidx;
1850                off_t base_offset = get_delta_base(p, w_curs, &curpos,
1851                                                   type, delta_obj_offset);
1852
1853                if (!base_offset)
1854                        return NULL;
1855
1856                revidx = find_pack_revindex(p, base_offset);
1857                if (!revidx)
1858                        return NULL;
1859
1860                return nth_packed_object_sha1(p, revidx->nr);
1861        } else
1862                return NULL;
1863}
1864
1865int unpack_object_header(struct packed_git *p,
1866                         struct pack_window **w_curs,
1867                         off_t *curpos,
1868                         unsigned long *sizep)
1869{
1870        unsigned char *base;
1871        unsigned long left;
1872        unsigned long used;
1873        enum object_type type;
1874
1875        /* use_pack() assures us we have [base, base + 20) available
1876         * as a range that we can look at.  (Its actually the hash
1877         * size that is assured.)  With our object header encoding
1878         * the maximum deflated object size is 2^137, which is just
1879         * insane, so we know won't exceed what we have been given.
1880         */
1881        base = use_pack(p, w_curs, *curpos, &left);
1882        used = unpack_object_header_buffer(base, left, &type, sizep);
1883        if (!used) {
1884                type = OBJ_BAD;
1885        } else
1886                *curpos += used;
1887
1888        return type;
1889}
1890
1891static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1892{
1893        int type;
1894        struct revindex_entry *revidx;
1895        const unsigned char *sha1;
1896        revidx = find_pack_revindex(p, obj_offset);
1897        if (!revidx)
1898                return OBJ_BAD;
1899        sha1 = nth_packed_object_sha1(p, revidx->nr);
1900        mark_bad_packed_object(p, sha1);
1901        type = sha1_object_info(sha1, NULL);
1902        if (type <= OBJ_NONE)
1903                return OBJ_BAD;
1904        return type;
1905}
1906
1907#define POI_STACK_PREALLOC 64
1908
1909static enum object_type packed_to_object_type(struct packed_git *p,
1910                                              off_t obj_offset,
1911                                              enum object_type type,
1912                                              struct pack_window **w_curs,
1913                                              off_t curpos)
1914{
1915        off_t small_poi_stack[POI_STACK_PREALLOC];
1916        off_t *poi_stack = small_poi_stack;
1917        int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1918
1919        while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1920                off_t base_offset;
1921                unsigned long size;
1922                /* Push the object we're going to leave behind */
1923                if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1924                        poi_stack_alloc = alloc_nr(poi_stack_nr);
1925                        ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1926                        memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1927                } else {
1928                        ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1929                }
1930                poi_stack[poi_stack_nr++] = obj_offset;
1931                /* If parsing the base offset fails, just unwind */
1932                base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1933                if (!base_offset)
1934                        goto unwind;
1935                curpos = obj_offset = base_offset;
1936                type = unpack_object_header(p, w_curs, &curpos, &size);
1937                if (type <= OBJ_NONE) {
1938                        /* If getting the base itself fails, we first
1939                         * retry the base, otherwise unwind */
1940                        type = retry_bad_packed_offset(p, base_offset);
1941                        if (type > OBJ_NONE)
1942                                goto out;
1943                        goto unwind;
1944                }
1945        }
1946
1947        switch (type) {
1948        case OBJ_BAD:
1949        case OBJ_COMMIT:
1950        case OBJ_TREE:
1951        case OBJ_BLOB:
1952        case OBJ_TAG:
1953                break;
1954        default:
1955                error("unknown object type %i at offset %"PRIuMAX" in %s",
1956                      type, (uintmax_t)obj_offset, p->pack_name);
1957                type = OBJ_BAD;
1958        }
1959
1960out:
1961        if (poi_stack != small_poi_stack)
1962                free(poi_stack);
1963        return type;
1964
1965unwind:
1966        while (poi_stack_nr) {
1967                obj_offset = poi_stack[--poi_stack_nr];
1968                type = retry_bad_packed_offset(p, obj_offset);
1969                if (type > OBJ_NONE)
1970                        goto out;
1971        }
1972        type = OBJ_BAD;
1973        goto out;
1974}
1975
1976static int packed_object_info(struct packed_git *p, off_t obj_offset,
1977                              struct object_info *oi)
1978{
1979        struct pack_window *w_curs = NULL;
1980        unsigned long size;
1981        off_t curpos = obj_offset;
1982        enum object_type type;
1983
1984        /*
1985         * We always get the representation type, but only convert it to
1986         * a "real" type later if the caller is interested.
1987         */
1988        type = unpack_object_header(p, &w_curs, &curpos, &size);
1989
1990        if (oi->sizep) {
1991                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1992                        off_t tmp_pos = curpos;
1993                        off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1994                                                           type, obj_offset);
1995                        if (!base_offset) {
1996                                type = OBJ_BAD;
1997                                goto out;
1998                        }
1999                        *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
2000                        if (*oi->sizep == 0) {
2001                                type = OBJ_BAD;
2002                                goto out;
2003                        }
2004                } else {
2005                        *oi->sizep = size;
2006                }
2007        }
2008
2009        if (oi->disk_sizep) {
2010                struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2011                *oi->disk_sizep = revidx[1].offset - obj_offset;
2012        }
2013
2014        if (oi->typep) {
2015                *oi->typep = packed_to_object_type(p, obj_offset, type, &w_curs, curpos);
2016                if (*oi->typep < 0) {
2017                        type = OBJ_BAD;
2018                        goto out;
2019                }
2020        }
2021
2022        if (oi->delta_base_sha1) {
2023                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2024                        const unsigned char *base;
2025
2026                        base = get_delta_base_sha1(p, &w_curs, curpos,
2027                                                   type, obj_offset);
2028                        if (!base) {
2029                                type = OBJ_BAD;
2030                                goto out;
2031                        }
2032
2033                        hashcpy(oi->delta_base_sha1, base);
2034                } else
2035                        hashclr(oi->delta_base_sha1);
2036        }
2037
2038out:
2039        unuse_pack(&w_curs);
2040        return type;
2041}
2042
2043static void *unpack_compressed_entry(struct packed_git *p,
2044                                    struct pack_window **w_curs,
2045                                    off_t curpos,
2046                                    unsigned long size)
2047{
2048        int st;
2049        git_zstream stream;
2050        unsigned char *buffer, *in;
2051
2052        buffer = xmallocz_gently(size);
2053        if (!buffer)
2054                return NULL;
2055        memset(&stream, 0, sizeof(stream));
2056        stream.next_out = buffer;
2057        stream.avail_out = size + 1;
2058
2059        git_inflate_init(&stream);
2060        do {
2061                in = use_pack(p, w_curs, curpos, &stream.avail_in);
2062                stream.next_in = in;
2063                st = git_inflate(&stream, Z_FINISH);
2064                if (!stream.avail_out)
2065                        break; /* the payload is larger than it should be */
2066                curpos += stream.next_in - in;
2067        } while (st == Z_OK || st == Z_BUF_ERROR);
2068        git_inflate_end(&stream);
2069        if ((st != Z_STREAM_END) || stream.total_out != size) {
2070                free(buffer);
2071                return NULL;
2072        }
2073
2074        return buffer;
2075}
2076
2077#define MAX_DELTA_CACHE (256)
2078
2079static size_t delta_base_cached;
2080
2081static LIST_HEAD(delta_base_cache_lru);
2082
2083static struct delta_base_cache_entry {
2084        struct list_head lru;
2085        void *data;
2086        struct packed_git *p;
2087        off_t base_offset;
2088        unsigned long size;
2089        enum object_type type;
2090} delta_base_cache[MAX_DELTA_CACHE];
2091
2092static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
2093{
2094        unsigned long hash;
2095
2096        hash = (unsigned long)(intptr_t)p + (unsigned long)base_offset;
2097        hash += (hash >> 8) + (hash >> 16);
2098        return hash % MAX_DELTA_CACHE;
2099}
2100
2101static struct delta_base_cache_entry *
2102get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
2103{
2104        unsigned long hash = pack_entry_hash(p, base_offset);
2105        return delta_base_cache + hash;
2106}
2107
2108static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent,
2109                                     struct packed_git *p, off_t base_offset)
2110{
2111        return (ent->data && ent->p == p && ent->base_offset == base_offset);
2112}
2113
2114static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
2115{
2116        struct delta_base_cache_entry *ent;
2117        ent = get_delta_base_cache_entry(p, base_offset);
2118        return eq_delta_base_cache_entry(ent, p, base_offset);
2119}
2120
2121/*
2122 * Remove the entry from the cache, but do _not_ free the associated
2123 * entry data. The caller takes ownership of the "data" buffer, and
2124 * should copy out any fields it wants before detaching.
2125 */
2126static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
2127{
2128        ent->data = NULL;
2129        list_del(&ent->lru);
2130        delta_base_cached -= ent->size;
2131}
2132
2133static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
2134        unsigned long *base_size, enum object_type *type)
2135{
2136        struct delta_base_cache_entry *ent;
2137
2138        ent = get_delta_base_cache_entry(p, base_offset);
2139
2140        if (!eq_delta_base_cache_entry(ent, p, base_offset))
2141                return unpack_entry(p, base_offset, type, base_size);
2142
2143        *type = ent->type;
2144        *base_size = ent->size;
2145        return xmemdupz(ent->data, ent->size);
2146}
2147
2148static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
2149{
2150        if (ent->data) {
2151                free(ent->data);
2152                detach_delta_base_cache_entry(ent);
2153        }
2154}
2155
2156void clear_delta_base_cache(void)
2157{
2158        unsigned long p;
2159        for (p = 0; p < MAX_DELTA_CACHE; p++)
2160                release_delta_base_cache(&delta_base_cache[p]);
2161}
2162
2163static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
2164        void *base, unsigned long base_size, enum object_type type)
2165{
2166        unsigned long hash = pack_entry_hash(p, base_offset);
2167        struct delta_base_cache_entry *ent = delta_base_cache + hash;
2168        struct list_head *lru;
2169
2170        release_delta_base_cache(ent);
2171        delta_base_cached += base_size;
2172
2173        list_for_each(lru, &delta_base_cache_lru) {
2174                struct delta_base_cache_entry *f =
2175                        list_entry(lru, struct delta_base_cache_entry, lru);
2176                if (delta_base_cached <= delta_base_cache_limit)
2177                        break;
2178                if (f->type == OBJ_BLOB)
2179                        release_delta_base_cache(f);
2180        }
2181        list_for_each(lru, &delta_base_cache_lru) {
2182                struct delta_base_cache_entry *f =
2183                        list_entry(lru, struct delta_base_cache_entry, lru);
2184                if (delta_base_cached <= delta_base_cache_limit)
2185                        break;
2186                release_delta_base_cache(f);
2187        }
2188
2189        ent->p = p;
2190        ent->base_offset = base_offset;
2191        ent->type = type;
2192        ent->data = base;
2193        ent->size = base_size;
2194        list_add_tail(&ent->lru, &delta_base_cache_lru);
2195}
2196
2197static void *read_object(const unsigned char *sha1, enum object_type *type,
2198                         unsigned long *size);
2199
2200static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
2201{
2202        static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
2203        trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
2204                         p->pack_name, (uintmax_t)obj_offset);
2205}
2206
2207int do_check_packed_object_crc;
2208
2209#define UNPACK_ENTRY_STACK_PREALLOC 64
2210struct unpack_entry_stack_ent {
2211        off_t obj_offset;
2212        off_t curpos;
2213        unsigned long size;
2214};
2215
2216void *unpack_entry(struct packed_git *p, off_t obj_offset,
2217                   enum object_type *final_type, unsigned long *final_size)
2218{
2219        struct pack_window *w_curs = NULL;
2220        off_t curpos = obj_offset;
2221        void *data = NULL;
2222        unsigned long size;
2223        enum object_type type;
2224        struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
2225        struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
2226        int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
2227        int base_from_cache = 0;
2228
2229        write_pack_access_log(p, obj_offset);
2230
2231        /* PHASE 1: drill down to the innermost base object */
2232        for (;;) {
2233                off_t base_offset;
2234                int i;
2235                struct delta_base_cache_entry *ent;
2236
2237                ent = get_delta_base_cache_entry(p, curpos);
2238                if (eq_delta_base_cache_entry(ent, p, curpos)) {
2239                        type = ent->type;
2240                        data = ent->data;
2241                        size = ent->size;
2242                        detach_delta_base_cache_entry(ent);
2243                        base_from_cache = 1;
2244                        break;
2245                }
2246
2247                if (do_check_packed_object_crc && p->index_version > 1) {
2248                        struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2249                        off_t len = revidx[1].offset - obj_offset;
2250                        if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
2251                                const unsigned char *sha1 =
2252                                        nth_packed_object_sha1(p, revidx->nr);
2253                                error("bad packed object CRC for %s",
2254                                      sha1_to_hex(sha1));
2255                                mark_bad_packed_object(p, sha1);
2256                                unuse_pack(&w_curs);
2257                                return NULL;
2258                        }
2259                }
2260
2261                type = unpack_object_header(p, &w_curs, &curpos, &size);
2262                if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
2263                        break;
2264
2265                base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
2266                if (!base_offset) {
2267                        error("failed to validate delta base reference "
2268                              "at offset %"PRIuMAX" from %s",
2269                              (uintmax_t)curpos, p->pack_name);
2270                        /* bail to phase 2, in hopes of recovery */
2271                        data = NULL;
2272                        break;
2273                }
2274
2275                /* push object, proceed to base */
2276                if (delta_stack_nr >= delta_stack_alloc
2277                    && delta_stack == small_delta_stack) {
2278                        delta_stack_alloc = alloc_nr(delta_stack_nr);
2279                        ALLOC_ARRAY(delta_stack, delta_stack_alloc);
2280                        memcpy(delta_stack, small_delta_stack,
2281                               sizeof(*delta_stack)*delta_stack_nr);
2282                } else {
2283                        ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
2284                }
2285                i = delta_stack_nr++;
2286                delta_stack[i].obj_offset = obj_offset;
2287                delta_stack[i].curpos = curpos;
2288                delta_stack[i].size = size;
2289
2290                curpos = obj_offset = base_offset;
2291        }
2292
2293        /* PHASE 2: handle the base */
2294        switch (type) {
2295        case OBJ_OFS_DELTA:
2296        case OBJ_REF_DELTA:
2297                if (data)
2298                        die("BUG: unpack_entry: left loop at a valid delta");
2299                break;
2300        case OBJ_COMMIT:
2301        case OBJ_TREE:
2302        case OBJ_BLOB:
2303        case OBJ_TAG:
2304                if (!base_from_cache)
2305                        data = unpack_compressed_entry(p, &w_curs, curpos, size);
2306                break;
2307        default:
2308                data = NULL;
2309                error("unknown object type %i at offset %"PRIuMAX" in %s",
2310                      type, (uintmax_t)obj_offset, p->pack_name);
2311        }
2312
2313        /* PHASE 3: apply deltas in order */
2314
2315        /* invariants:
2316         *   'data' holds the base data, or NULL if there was corruption
2317         */
2318        while (delta_stack_nr) {
2319                void *delta_data;
2320                void *base = data;
2321                unsigned long delta_size, base_size = size;
2322                int i;
2323
2324                data = NULL;
2325
2326                if (base)
2327                        add_delta_base_cache(p, obj_offset, base, base_size, type);
2328
2329                if (!base) {
2330                        /*
2331                         * We're probably in deep shit, but let's try to fetch
2332                         * the required base anyway from another pack or loose.
2333                         * This is costly but should happen only in the presence
2334                         * of a corrupted pack, and is better than failing outright.
2335                         */
2336                        struct revindex_entry *revidx;
2337                        const unsigned char *base_sha1;
2338                        revidx = find_pack_revindex(p, obj_offset);
2339                        if (revidx) {
2340                                base_sha1 = nth_packed_object_sha1(p, revidx->nr);
2341                                error("failed to read delta base object %s"
2342                                      " at offset %"PRIuMAX" from %s",
2343                                      sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
2344                                      p->pack_name);
2345                                mark_bad_packed_object(p, base_sha1);
2346                                base = read_object(base_sha1, &type, &base_size);
2347                        }
2348                }
2349
2350                i = --delta_stack_nr;
2351                obj_offset = delta_stack[i].obj_offset;
2352                curpos = delta_stack[i].curpos;
2353                delta_size = delta_stack[i].size;
2354
2355                if (!base)
2356                        continue;
2357
2358                delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
2359
2360                if (!delta_data) {
2361                        error("failed to unpack compressed delta "
2362                              "at offset %"PRIuMAX" from %s",
2363                              (uintmax_t)curpos, p->pack_name);
2364                        data = NULL;
2365                        continue;
2366                }
2367
2368                data = patch_delta(base, base_size,
2369                                   delta_data, delta_size,
2370                                   &size);
2371
2372                /*
2373                 * We could not apply the delta; warn the user, but keep going.
2374                 * Our failure will be noticed either in the next iteration of
2375                 * the loop, or if this is the final delta, in the caller when
2376                 * we return NULL. Those code paths will take care of making
2377                 * a more explicit warning and retrying with another copy of
2378                 * the object.
2379                 */
2380                if (!data)
2381                        error("failed to apply delta");
2382
2383                free(delta_data);
2384        }
2385
2386        *final_type = type;
2387        *final_size = size;
2388
2389        unuse_pack(&w_curs);
2390
2391        if (delta_stack != small_delta_stack)
2392                free(delta_stack);
2393
2394        return data;
2395}
2396
2397const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2398                                            uint32_t n)
2399{
2400        const unsigned char *index = p->index_data;
2401        if (!index) {
2402                if (open_pack_index(p))
2403                        return NULL;
2404                index = p->index_data;
2405        }
2406        if (n >= p->num_objects)
2407                return NULL;
2408        index += 4 * 256;
2409        if (p->index_version == 1) {
2410                return index + 24 * n + 4;
2411        } else {
2412                index += 8;
2413                return index + 20 * n;
2414        }
2415}
2416
2417void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
2418{
2419        const unsigned char *ptr = vptr;
2420        const unsigned char *start = p->index_data;
2421        const unsigned char *end = start + p->index_size;
2422        if (ptr < start)
2423                die(_("offset before start of pack index for %s (corrupt index?)"),
2424                    p->pack_name);
2425        /* No need to check for underflow; .idx files must be at least 8 bytes */
2426        if (ptr >= end - 8)
2427                die(_("offset beyond end of pack index for %s (truncated index?)"),
2428                    p->pack_name);
2429}
2430
2431off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2432{
2433        const unsigned char *index = p->index_data;
2434        index += 4 * 256;
2435        if (p->index_version == 1) {
2436                return ntohl(*((uint32_t *)(index + 24 * n)));
2437        } else {
2438                uint32_t off;
2439                index += 8 + p->num_objects * (20 + 4);
2440                off = ntohl(*((uint32_t *)(index + 4 * n)));
2441                if (!(off & 0x80000000))
2442                        return off;
2443                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2444                check_pack_index_ptr(p, index);
2445                return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2446                                   ntohl(*((uint32_t *)(index + 4)));
2447        }
2448}
2449
2450off_t find_pack_entry_one(const unsigned char *sha1,
2451                                  struct packed_git *p)
2452{
2453        const uint32_t *level1_ofs = p->index_data;
2454        const unsigned char *index = p->index_data;
2455        unsigned hi, lo, stride;
2456        static int use_lookup = -1;
2457        static int debug_lookup = -1;
2458
2459        if (debug_lookup < 0)
2460                debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2461
2462        if (!index) {
2463                if (open_pack_index(p))
2464                        return 0;
2465                level1_ofs = p->index_data;
2466                index = p->index_data;
2467        }
2468        if (p->index_version > 1) {
2469                level1_ofs += 2;
2470                index += 8;
2471        }
2472        index += 4 * 256;
2473        hi = ntohl(level1_ofs[*sha1]);
2474        lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2475        if (p->index_version > 1) {
2476                stride = 20;
2477        } else {
2478                stride = 24;
2479                index += 4;
2480        }
2481
2482        if (debug_lookup)
2483                printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2484                       sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2485
2486        if (use_lookup < 0)
2487                use_lookup = !!getenv("GIT_USE_LOOKUP");
2488        if (use_lookup) {
2489                int pos = sha1_entry_pos(index, stride, 0,
2490                                         lo, hi, p->num_objects, sha1);
2491                if (pos < 0)
2492                        return 0;
2493                return nth_packed_object_offset(p, pos);
2494        }
2495
2496        do {
2497                unsigned mi = (lo + hi) / 2;
2498                int cmp = hashcmp(index + mi * stride, sha1);
2499
2500                if (debug_lookup)
2501                        printf("lo %u hi %u rg %u mi %u\n",
2502                               lo, hi, hi - lo, mi);
2503                if (!cmp)
2504                        return nth_packed_object_offset(p, mi);
2505                if (cmp > 0)
2506                        hi = mi;
2507                else
2508                        lo = mi+1;
2509        } while (lo < hi);
2510        return 0;
2511}
2512
2513int is_pack_valid(struct packed_git *p)
2514{
2515        /* An already open pack is known to be valid. */
2516        if (p->pack_fd != -1)
2517                return 1;
2518
2519        /* If the pack has one window completely covering the
2520         * file size, the pack is known to be valid even if
2521         * the descriptor is not currently open.
2522         */
2523        if (p->windows) {
2524                struct pack_window *w = p->windows;
2525
2526                if (!w->offset && w->len == p->pack_size)
2527                        return 1;
2528        }
2529
2530        /* Force the pack to open to prove its valid. */
2531        return !open_packed_git(p);
2532}
2533
2534static int fill_pack_entry(const unsigned char *sha1,
2535                           struct pack_entry *e,
2536                           struct packed_git *p)
2537{
2538        off_t offset;
2539
2540        if (p->num_bad_objects) {
2541                unsigned i;
2542                for (i = 0; i < p->num_bad_objects; i++)
2543                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2544                                return 0;
2545        }
2546
2547        offset = find_pack_entry_one(sha1, p);
2548        if (!offset)
2549                return 0;
2550
2551        /*
2552         * We are about to tell the caller where they can locate the
2553         * requested object.  We better make sure the packfile is
2554         * still here and can be accessed before supplying that
2555         * answer, as it may have been deleted since the index was
2556         * loaded!
2557         */
2558        if (!is_pack_valid(p))
2559                return 0;
2560        e->offset = offset;
2561        e->p = p;
2562        hashcpy(e->sha1, sha1);
2563        return 1;
2564}
2565
2566/*
2567 * Iff a pack file contains the object named by sha1, return true and
2568 * store its location to e.
2569 */
2570static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2571{
2572        struct mru_entry *p;
2573
2574        prepare_packed_git();
2575        if (!packed_git)
2576                return 0;
2577
2578        for (p = packed_git_mru->head; p; p = p->next) {
2579                if (fill_pack_entry(sha1, e, p->item)) {
2580                        mru_mark(packed_git_mru, p);
2581                        return 1;
2582                }
2583        }
2584        return 0;
2585}
2586
2587struct packed_git *find_sha1_pack(const unsigned char *sha1,
2588                                  struct packed_git *packs)
2589{
2590        struct packed_git *p;
2591
2592        for (p = packs; p; p = p->next) {
2593                if (find_pack_entry_one(sha1, p))
2594                        return p;
2595        }
2596        return NULL;
2597
2598}
2599
2600static int sha1_loose_object_info(const unsigned char *sha1,
2601                                  struct object_info *oi,
2602                                  int flags)
2603{
2604        int status = 0;
2605        unsigned long mapsize;
2606        void *map;
2607        git_zstream stream;
2608        char hdr[32];
2609        struct strbuf hdrbuf = STRBUF_INIT;
2610
2611        if (oi->delta_base_sha1)
2612                hashclr(oi->delta_base_sha1);
2613
2614        /*
2615         * If we don't care about type or size, then we don't
2616         * need to look inside the object at all. Note that we
2617         * do not optimize out the stat call, even if the
2618         * caller doesn't care about the disk-size, since our
2619         * return value implicitly indicates whether the
2620         * object even exists.
2621         */
2622        if (!oi->typep && !oi->typename && !oi->sizep) {
2623                struct stat st;
2624                if (stat_sha1_file(sha1, &st) < 0)
2625                        return -1;
2626                if (oi->disk_sizep)
2627                        *oi->disk_sizep = st.st_size;
2628                return 0;
2629        }
2630
2631        map = map_sha1_file(sha1, &mapsize);
2632        if (!map)
2633                return -1;
2634        if (oi->disk_sizep)
2635                *oi->disk_sizep = mapsize;
2636        if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
2637                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
2638                        status = error("unable to unpack %s header with --allow-unknown-type",
2639                                       sha1_to_hex(sha1));
2640        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2641                status = error("unable to unpack %s header",
2642                               sha1_to_hex(sha1));
2643        if (status < 0)
2644                ; /* Do nothing */
2645        else if (hdrbuf.len) {
2646                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
2647                        status = error("unable to parse %s header with --allow-unknown-type",
2648                                       sha1_to_hex(sha1));
2649        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
2650                status = error("unable to parse %s header", sha1_to_hex(sha1));
2651        git_inflate_end(&stream);
2652        munmap(map, mapsize);
2653        if (status && oi->typep)
2654                *oi->typep = status;
2655        strbuf_release(&hdrbuf);
2656        return 0;
2657}
2658
2659int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
2660{
2661        struct cached_object *co;
2662        struct pack_entry e;
2663        int rtype;
2664        enum object_type real_type;
2665        const unsigned char *real = lookup_replace_object_extended(sha1, flags);
2666
2667        co = find_cached_object(real);
2668        if (co) {
2669                if (oi->typep)
2670                        *(oi->typep) = co->type;
2671                if (oi->sizep)
2672                        *(oi->sizep) = co->size;
2673                if (oi->disk_sizep)
2674                        *(oi->disk_sizep) = 0;
2675                if (oi->delta_base_sha1)
2676                        hashclr(oi->delta_base_sha1);
2677                if (oi->typename)
2678                        strbuf_addstr(oi->typename, typename(co->type));
2679                oi->whence = OI_CACHED;
2680                return 0;
2681        }
2682
2683        if (!find_pack_entry(real, &e)) {
2684                /* Most likely it's a loose object. */
2685                if (!sha1_loose_object_info(real, oi, flags)) {
2686                        oi->whence = OI_LOOSE;
2687                        return 0;
2688                }
2689
2690                /* Not a loose object; someone else may have just packed it. */
2691                reprepare_packed_git();
2692                if (!find_pack_entry(real, &e))
2693                        return -1;
2694        }
2695
2696        /*
2697         * packed_object_info() does not follow the delta chain to
2698         * find out the real type, unless it is given oi->typep.
2699         */
2700        if (oi->typename && !oi->typep)
2701                oi->typep = &real_type;
2702
2703        rtype = packed_object_info(e.p, e.offset, oi);
2704        if (rtype < 0) {
2705                mark_bad_packed_object(e.p, real);
2706                if (oi->typep == &real_type)
2707                        oi->typep = NULL;
2708                return sha1_object_info_extended(real, oi, 0);
2709        } else if (in_delta_base_cache(e.p, e.offset)) {
2710                oi->whence = OI_DBCACHED;
2711        } else {
2712                oi->whence = OI_PACKED;
2713                oi->u.packed.offset = e.offset;
2714                oi->u.packed.pack = e.p;
2715                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2716                                         rtype == OBJ_OFS_DELTA);
2717        }
2718        if (oi->typename)
2719                strbuf_addstr(oi->typename, typename(*oi->typep));
2720        if (oi->typep == &real_type)
2721                oi->typep = NULL;
2722
2723        return 0;
2724}
2725
2726/* returns enum object_type or negative */
2727int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2728{
2729        enum object_type type;
2730        struct object_info oi = {NULL};
2731
2732        oi.typep = &type;
2733        oi.sizep = sizep;
2734        if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
2735                return -1;
2736        return type;
2737}
2738
2739static void *read_packed_sha1(const unsigned char *sha1,
2740                              enum object_type *type, unsigned long *size)
2741{
2742        struct pack_entry e;
2743        void *data;
2744
2745        if (!find_pack_entry(sha1, &e))
2746                return NULL;
2747        data = cache_or_unpack_entry(e.p, e.offset, size, type);
2748        if (!data) {
2749                /*
2750                 * We're probably in deep shit, but let's try to fetch
2751                 * the required object anyway from another pack or loose.
2752                 * This should happen only in the presence of a corrupted
2753                 * pack, and is better than failing outright.
2754                 */
2755                error("failed to read object %s at offset %"PRIuMAX" from %s",
2756                      sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2757                mark_bad_packed_object(e.p, sha1);
2758                data = read_object(sha1, type, size);
2759        }
2760        return data;
2761}
2762
2763int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2764                      unsigned char *sha1)
2765{
2766        struct cached_object *co;
2767
2768        hash_sha1_file(buf, len, typename(type), sha1);
2769        if (has_sha1_file(sha1) || find_cached_object(sha1))
2770                return 0;
2771        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
2772        co = &cached_objects[cached_object_nr++];
2773        co->size = len;
2774        co->type = type;
2775        co->buf = xmalloc(len);
2776        memcpy(co->buf, buf, len);
2777        hashcpy(co->sha1, sha1);
2778        return 0;
2779}
2780
2781static void *read_object(const unsigned char *sha1, enum object_type *type,
2782                         unsigned long *size)
2783{
2784        unsigned long mapsize;
2785        void *map, *buf;
2786        struct cached_object *co;
2787
2788        co = find_cached_object(sha1);
2789        if (co) {
2790                *type = co->type;
2791                *size = co->size;
2792                return xmemdupz(co->buf, co->size);
2793        }
2794
2795        buf = read_packed_sha1(sha1, type, size);
2796        if (buf)
2797                return buf;
2798        map = map_sha1_file(sha1, &mapsize);
2799        if (map) {
2800                buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2801                munmap(map, mapsize);
2802                return buf;
2803        }
2804        reprepare_packed_git();
2805        return read_packed_sha1(sha1, type, size);
2806}
2807
2808/*
2809 * This function dies on corrupt objects; the callers who want to
2810 * deal with them should arrange to call read_object() and give error
2811 * messages themselves.
2812 */
2813void *read_sha1_file_extended(const unsigned char *sha1,
2814                              enum object_type *type,
2815                              unsigned long *size,
2816                              unsigned flag)
2817{
2818        void *data;
2819        const struct packed_git *p;
2820        const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
2821
2822        errno = 0;
2823        data = read_object(repl, type, size);
2824        if (data)
2825                return data;
2826
2827        if (errno && errno != ENOENT)
2828                die_errno("failed to read object %s", sha1_to_hex(sha1));
2829
2830        /* die if we replaced an object with one that does not exist */
2831        if (repl != sha1)
2832                die("replacement %s not found for %s",
2833                    sha1_to_hex(repl), sha1_to_hex(sha1));
2834
2835        if (has_loose_object(repl)) {
2836                const char *path = sha1_file_name(sha1);
2837
2838                die("loose object %s (stored in %s) is corrupt",
2839                    sha1_to_hex(repl), path);
2840        }
2841
2842        if ((p = has_packed_and_bad(repl)) != NULL)
2843                die("packed object %s (stored in %s) is corrupt",
2844                    sha1_to_hex(repl), p->pack_name);
2845
2846        return NULL;
2847}
2848
2849void *read_object_with_reference(const unsigned char *sha1,
2850                                 const char *required_type_name,
2851                                 unsigned long *size,
2852                                 unsigned char *actual_sha1_return)
2853{
2854        enum object_type type, required_type;
2855        void *buffer;
2856        unsigned long isize;
2857        unsigned char actual_sha1[20];
2858
2859        required_type = type_from_string(required_type_name);
2860        hashcpy(actual_sha1, sha1);
2861        while (1) {
2862                int ref_length = -1;
2863                const char *ref_type = NULL;
2864
2865                buffer = read_sha1_file(actual_sha1, &type, &isize);
2866                if (!buffer)
2867                        return NULL;
2868                if (type == required_type) {
2869                        *size = isize;
2870                        if (actual_sha1_return)
2871                                hashcpy(actual_sha1_return, actual_sha1);
2872                        return buffer;
2873                }
2874                /* Handle references */
2875                else if (type == OBJ_COMMIT)
2876                        ref_type = "tree ";
2877                else if (type == OBJ_TAG)
2878                        ref_type = "object ";
2879                else {
2880                        free(buffer);
2881                        return NULL;
2882                }
2883                ref_length = strlen(ref_type);
2884
2885                if (ref_length + 40 > isize ||
2886                    memcmp(buffer, ref_type, ref_length) ||
2887                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2888                        free(buffer);
2889                        return NULL;
2890                }
2891                free(buffer);
2892                /* Now we have the ID of the referred-to object in
2893                 * actual_sha1.  Check again. */
2894        }
2895}
2896
2897static void write_sha1_file_prepare(const void *buf, unsigned long len,
2898                                    const char *type, unsigned char *sha1,
2899                                    char *hdr, int *hdrlen)
2900{
2901        git_SHA_CTX c;
2902
2903        /* Generate the header */
2904        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
2905
2906        /* Sha1.. */
2907        git_SHA1_Init(&c);
2908        git_SHA1_Update(&c, hdr, *hdrlen);
2909        git_SHA1_Update(&c, buf, len);
2910        git_SHA1_Final(sha1, &c);
2911}
2912
2913/*
2914 * Move the just written object into its final resting place.
2915 */
2916int finalize_object_file(const char *tmpfile, const char *filename)
2917{
2918        int ret = 0;
2919
2920        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2921                goto try_rename;
2922        else if (link(tmpfile, filename))
2923                ret = errno;
2924
2925        /*
2926         * Coda hack - coda doesn't like cross-directory links,
2927         * so we fall back to a rename, which will mean that it
2928         * won't be able to check collisions, but that's not a
2929         * big deal.
2930         *
2931         * The same holds for FAT formatted media.
2932         *
2933         * When this succeeds, we just return.  We have nothing
2934         * left to unlink.
2935         */
2936        if (ret && ret != EEXIST) {
2937        try_rename:
2938                if (!rename(tmpfile, filename))
2939                        goto out;
2940                ret = errno;
2941        }
2942        unlink_or_warn(tmpfile);
2943        if (ret) {
2944                if (ret != EEXIST) {
2945                        return error_errno("unable to write sha1 filename %s", filename);
2946                }
2947                /* FIXME!!! Collision check here ? */
2948        }
2949
2950out:
2951        if (adjust_shared_perm(filename))
2952                return error("unable to set permission to '%s'", filename);
2953        return 0;
2954}
2955
2956static int write_buffer(int fd, const void *buf, size_t len)
2957{
2958        if (write_in_full(fd, buf, len) < 0)
2959                return error_errno("file write error");
2960        return 0;
2961}
2962
2963int hash_sha1_file(const void *buf, unsigned long len, const char *type,
2964                   unsigned char *sha1)
2965{
2966        char hdr[32];
2967        int hdrlen = sizeof(hdr);
2968        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
2969        return 0;
2970}
2971
2972/* Finalize a file on disk, and close it. */
2973static void close_sha1_file(int fd)
2974{
2975        if (fsync_object_files)
2976                fsync_or_die(fd, "sha1 file");
2977        if (close(fd) != 0)
2978                die_errno("error when closing sha1 file");
2979}
2980
2981/* Size of directory component, including the ending '/' */
2982static inline int directory_size(const char *filename)
2983{
2984        const char *s = strrchr(filename, '/');
2985        if (!s)
2986                return 0;
2987        return s - filename + 1;
2988}
2989
2990/*
2991 * This creates a temporary file in the same directory as the final
2992 * 'filename'
2993 *
2994 * We want to avoid cross-directory filename renames, because those
2995 * can have problems on various filesystems (FAT, NFS, Coda).
2996 */
2997static int create_tmpfile(struct strbuf *tmp, const char *filename)
2998{
2999        int fd, dirlen = directory_size(filename);
3000
3001        strbuf_reset(tmp);
3002        strbuf_add(tmp, filename, dirlen);
3003        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
3004        fd = git_mkstemp_mode(tmp->buf, 0444);
3005        if (fd < 0 && dirlen && errno == ENOENT) {
3006                /*
3007                 * Make sure the directory exists; note that the contents
3008                 * of the buffer are undefined after mkstemp returns an
3009                 * error, so we have to rewrite the whole buffer from
3010                 * scratch.
3011                 */
3012                strbuf_reset(tmp);
3013                strbuf_add(tmp, filename, dirlen - 1);
3014                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
3015                        return -1;
3016                if (adjust_shared_perm(tmp->buf))
3017                        return -1;
3018
3019                /* Try again */
3020                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
3021                fd = git_mkstemp_mode(tmp->buf, 0444);
3022        }
3023        return fd;
3024}
3025
3026static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
3027                              const void *buf, unsigned long len, time_t mtime)
3028{
3029        int fd, ret;
3030        unsigned char compressed[4096];
3031        git_zstream stream;
3032        git_SHA_CTX c;
3033        unsigned char parano_sha1[20];
3034        static struct strbuf tmp_file = STRBUF_INIT;
3035        const char *filename = sha1_file_name(sha1);
3036
3037        fd = create_tmpfile(&tmp_file, filename);
3038        if (fd < 0) {
3039                if (errno == EACCES)
3040                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
3041                else
3042                        return error_errno("unable to create temporary file");
3043        }
3044
3045        /* Set it up */
3046        git_deflate_init(&stream, zlib_compression_level);
3047        stream.next_out = compressed;
3048        stream.avail_out = sizeof(compressed);
3049        git_SHA1_Init(&c);
3050
3051        /* First header.. */
3052        stream.next_in = (unsigned char *)hdr;
3053        stream.avail_in = hdrlen;
3054        while (git_deflate(&stream, 0) == Z_OK)
3055                ; /* nothing */
3056        git_SHA1_Update(&c, hdr, hdrlen);
3057
3058        /* Then the data itself.. */
3059        stream.next_in = (void *)buf;
3060        stream.avail_in = len;
3061        do {
3062                unsigned char *in0 = stream.next_in;
3063                ret = git_deflate(&stream, Z_FINISH);
3064                git_SHA1_Update(&c, in0, stream.next_in - in0);
3065                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
3066                        die("unable to write sha1 file");
3067                stream.next_out = compressed;
3068                stream.avail_out = sizeof(compressed);
3069        } while (ret == Z_OK);
3070
3071        if (ret != Z_STREAM_END)
3072                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
3073        ret = git_deflate_end_gently(&stream);
3074        if (ret != Z_OK)
3075                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
3076        git_SHA1_Final(parano_sha1, &c);
3077        if (hashcmp(sha1, parano_sha1) != 0)
3078                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
3079
3080        close_sha1_file(fd);
3081
3082        if (mtime) {
3083                struct utimbuf utb;
3084                utb.actime = mtime;
3085                utb.modtime = mtime;
3086                if (utime(tmp_file.buf, &utb) < 0)
3087                        warning_errno("failed utime() on %s", tmp_file.buf);
3088        }
3089
3090        return finalize_object_file(tmp_file.buf, filename);
3091}
3092
3093static int freshen_loose_object(const unsigned char *sha1)
3094{
3095        return check_and_freshen(sha1, 1);
3096}
3097
3098static int freshen_packed_object(const unsigned char *sha1)
3099{
3100        struct pack_entry e;
3101        if (!find_pack_entry(sha1, &e))
3102                return 0;
3103        if (e.p->freshened)
3104                return 1;
3105        if (!freshen_file(e.p->pack_name))
3106                return 0;
3107        e.p->freshened = 1;
3108        return 1;
3109}
3110
3111int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
3112{
3113        char hdr[32];
3114        int hdrlen = sizeof(hdr);
3115
3116        /* Normally if we have it in the pack then we do not bother writing
3117         * it out into .git/objects/??/?{38} file.
3118         */
3119        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3120        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3121                return 0;
3122        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
3123}
3124
3125int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
3126                             unsigned char *sha1, unsigned flags)
3127{
3128        char *header;
3129        int hdrlen, status = 0;
3130
3131        /* type string, SP, %lu of the length plus NUL must fit this */
3132        hdrlen = strlen(type) + 32;
3133        header = xmalloc(hdrlen);
3134        write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
3135
3136        if (!(flags & HASH_WRITE_OBJECT))
3137                goto cleanup;
3138        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3139                goto cleanup;
3140        status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
3141
3142cleanup:
3143        free(header);
3144        return status;
3145}
3146
3147int force_object_loose(const unsigned char *sha1, time_t mtime)
3148{
3149        void *buf;
3150        unsigned long len;
3151        enum object_type type;
3152        char hdr[32];
3153        int hdrlen;
3154        int ret;
3155
3156        if (has_loose_object(sha1))
3157                return 0;
3158        buf = read_packed_sha1(sha1, &type, &len);
3159        if (!buf)
3160                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
3161        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
3162        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
3163        free(buf);
3164
3165        return ret;
3166}
3167
3168int has_pack_index(const unsigned char *sha1)
3169{
3170        struct stat st;
3171        if (stat(sha1_pack_index_name(sha1), &st))
3172                return 0;
3173        return 1;
3174}
3175
3176int has_sha1_pack(const unsigned char *sha1)
3177{
3178        struct pack_entry e;
3179        return find_pack_entry(sha1, &e);
3180}
3181
3182int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
3183{
3184        struct pack_entry e;
3185
3186        if (find_pack_entry(sha1, &e))
3187                return 1;
3188        if (has_loose_object(sha1))
3189                return 1;
3190        if (flags & HAS_SHA1_QUICK)
3191                return 0;
3192        reprepare_packed_git();
3193        return find_pack_entry(sha1, &e);
3194}
3195
3196int has_object_file(const struct object_id *oid)
3197{
3198        return has_sha1_file(oid->hash);
3199}
3200
3201static void check_tree(const void *buf, size_t size)
3202{
3203        struct tree_desc desc;
3204        struct name_entry entry;
3205
3206        init_tree_desc(&desc, buf, size);
3207        while (tree_entry(&desc, &entry))
3208                /* do nothing
3209                 * tree_entry() will die() on malformed entries */
3210                ;
3211}
3212
3213static void check_commit(const void *buf, size_t size)
3214{
3215        struct commit c;
3216        memset(&c, 0, sizeof(c));
3217        if (parse_commit_buffer(&c, buf, size))
3218                die("corrupt commit");
3219}
3220
3221static void check_tag(const void *buf, size_t size)
3222{
3223        struct tag t;
3224        memset(&t, 0, sizeof(t));
3225        if (parse_tag_buffer(&t, buf, size))
3226                die("corrupt tag");
3227}
3228
3229static int index_mem(unsigned char *sha1, void *buf, size_t size,
3230                     enum object_type type,
3231                     const char *path, unsigned flags)
3232{
3233        int ret, re_allocated = 0;
3234        int write_object = flags & HASH_WRITE_OBJECT;
3235
3236        if (!type)
3237                type = OBJ_BLOB;
3238
3239        /*
3240         * Convert blobs to git internal format
3241         */
3242        if ((type == OBJ_BLOB) && path) {
3243                struct strbuf nbuf = STRBUF_INIT;
3244                if (convert_to_git(path, buf, size, &nbuf,
3245                                   write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
3246                        buf = strbuf_detach(&nbuf, &size);
3247                        re_allocated = 1;
3248                }
3249        }
3250        if (flags & HASH_FORMAT_CHECK) {
3251                if (type == OBJ_TREE)
3252                        check_tree(buf, size);
3253                if (type == OBJ_COMMIT)
3254                        check_commit(buf, size);
3255                if (type == OBJ_TAG)
3256                        check_tag(buf, size);
3257        }
3258
3259        if (write_object)
3260                ret = write_sha1_file(buf, size, typename(type), sha1);
3261        else
3262                ret = hash_sha1_file(buf, size, typename(type), sha1);
3263        if (re_allocated)
3264                free(buf);
3265        return ret;
3266}
3267
3268static int index_stream_convert_blob(unsigned char *sha1, int fd,
3269                                     const char *path, unsigned flags)
3270{
3271        int ret;
3272        const int write_object = flags & HASH_WRITE_OBJECT;
3273        struct strbuf sbuf = STRBUF_INIT;
3274
3275        assert(path);
3276        assert(would_convert_to_git_filter_fd(path));
3277
3278        convert_to_git_filter_fd(path, fd, &sbuf,
3279                                 write_object ? safe_crlf : SAFE_CRLF_FALSE);
3280
3281        if (write_object)
3282                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3283                                      sha1);
3284        else
3285                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3286                                     sha1);
3287        strbuf_release(&sbuf);
3288        return ret;
3289}
3290
3291static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
3292                      const char *path, unsigned flags)
3293{
3294        struct strbuf sbuf = STRBUF_INIT;
3295        int ret;
3296
3297        if (strbuf_read(&sbuf, fd, 4096) >= 0)
3298                ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
3299        else
3300                ret = -1;
3301        strbuf_release(&sbuf);
3302        return ret;
3303}
3304
3305#define SMALL_FILE_SIZE (32*1024)
3306
3307static int index_core(unsigned char *sha1, int fd, size_t size,
3308                      enum object_type type, const char *path,
3309                      unsigned flags)
3310{
3311        int ret;
3312
3313        if (!size) {
3314                ret = index_mem(sha1, "", size, type, path, flags);
3315        } else if (size <= SMALL_FILE_SIZE) {
3316                char *buf = xmalloc(size);
3317                if (size == read_in_full(fd, buf, size))
3318                        ret = index_mem(sha1, buf, size, type, path, flags);
3319                else
3320                        ret = error_errno("short read");
3321                free(buf);
3322        } else {
3323                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
3324                ret = index_mem(sha1, buf, size, type, path, flags);
3325                munmap(buf, size);
3326        }
3327        return ret;
3328}
3329
3330/*
3331 * This creates one packfile per large blob unless bulk-checkin
3332 * machinery is "plugged".
3333 *
3334 * This also bypasses the usual "convert-to-git" dance, and that is on
3335 * purpose. We could write a streaming version of the converting
3336 * functions and insert that before feeding the data to fast-import
3337 * (or equivalent in-core API described above). However, that is
3338 * somewhat complicated, as we do not know the size of the filter
3339 * result, which we need to know beforehand when writing a git object.
3340 * Since the primary motivation for trying to stream from the working
3341 * tree file and to avoid mmaping it in core is to deal with large
3342 * binary blobs, they generally do not want to get any conversion, and
3343 * callers should avoid this code path when filters are requested.
3344 */
3345static int index_stream(unsigned char *sha1, int fd, size_t size,
3346                        enum object_type type, const char *path,
3347                        unsigned flags)
3348{
3349        return index_bulk_checkin(sha1, fd, size, type, path, flags);
3350}
3351
3352int index_fd(unsigned char *sha1, int fd, struct stat *st,
3353             enum object_type type, const char *path, unsigned flags)
3354{
3355        int ret;
3356
3357        /*
3358         * Call xsize_t() only when needed to avoid potentially unnecessary
3359         * die() for large files.
3360         */
3361        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
3362                ret = index_stream_convert_blob(sha1, fd, path, flags);
3363        else if (!S_ISREG(st->st_mode))
3364                ret = index_pipe(sha1, fd, type, path, flags);
3365        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
3366                 (path && would_convert_to_git(path)))
3367                ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
3368                                 flags);
3369        else
3370                ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
3371                                   flags);
3372        close(fd);
3373        return ret;
3374}
3375
3376int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
3377{
3378        int fd;
3379        struct strbuf sb = STRBUF_INIT;
3380
3381        switch (st->st_mode & S_IFMT) {
3382        case S_IFREG:
3383                fd = open(path, O_RDONLY);
3384                if (fd < 0)
3385                        return error_errno("open(\"%s\")", path);
3386                if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
3387                        return error("%s: failed to insert into database",
3388                                     path);
3389                break;
3390        case S_IFLNK:
3391                if (strbuf_readlink(&sb, path, st->st_size))
3392                        return error_errno("readlink(\"%s\")", path);
3393                if (!(flags & HASH_WRITE_OBJECT))
3394                        hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
3395                else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
3396                        return error("%s: failed to insert into database",
3397                                     path);
3398                strbuf_release(&sb);
3399                break;
3400        case S_IFDIR:
3401                return resolve_gitlink_ref(path, "HEAD", sha1);
3402        default:
3403                return error("%s: unsupported file type", path);
3404        }
3405        return 0;
3406}
3407
3408int read_pack_header(int fd, struct pack_header *header)
3409{
3410        if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
3411                /* "eof before pack header was fully read" */
3412                return PH_ERROR_EOF;
3413
3414        if (header->hdr_signature != htonl(PACK_SIGNATURE))
3415                /* "protocol error (pack signature mismatch detected)" */
3416                return PH_ERROR_PACK_SIGNATURE;
3417        if (!pack_version_ok(header->hdr_version))
3418                /* "protocol error (pack version unsupported)" */
3419                return PH_ERROR_PROTOCOL;
3420        return 0;
3421}
3422
3423void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
3424{
3425        enum object_type type = sha1_object_info(sha1, NULL);
3426        if (type < 0)
3427                die("%s is not a valid object", sha1_to_hex(sha1));
3428        if (type != expect)
3429                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
3430                    typename(expect));
3431}
3432
3433static int for_each_file_in_obj_subdir(int subdir_nr,
3434                                       struct strbuf *path,
3435                                       each_loose_object_fn obj_cb,
3436                                       each_loose_cruft_fn cruft_cb,
3437                                       each_loose_subdir_fn subdir_cb,
3438                                       void *data)
3439{
3440        size_t baselen = path->len;
3441        DIR *dir = opendir(path->buf);
3442        struct dirent *de;
3443        int r = 0;
3444
3445        if (!dir) {
3446                if (errno == ENOENT)
3447                        return 0;
3448                return error_errno("unable to open %s", path->buf);
3449        }
3450
3451        while ((de = readdir(dir))) {
3452                if (is_dot_or_dotdot(de->d_name))
3453                        continue;
3454
3455                strbuf_setlen(path, baselen);
3456                strbuf_addf(path, "/%s", de->d_name);
3457
3458                if (strlen(de->d_name) == 38)  {
3459                        char hex[41];
3460                        unsigned char sha1[20];
3461
3462                        snprintf(hex, sizeof(hex), "%02x%s",
3463                                 subdir_nr, de->d_name);
3464                        if (!get_sha1_hex(hex, sha1)) {
3465                                if (obj_cb) {
3466                                        r = obj_cb(sha1, path->buf, data);
3467                                        if (r)
3468                                                break;
3469                                }
3470                                continue;
3471                        }
3472                }
3473
3474                if (cruft_cb) {
3475                        r = cruft_cb(de->d_name, path->buf, data);
3476                        if (r)
3477                                break;
3478                }
3479        }
3480        closedir(dir);
3481
3482        strbuf_setlen(path, baselen);
3483        if (!r && subdir_cb)
3484                r = subdir_cb(subdir_nr, path->buf, data);
3485
3486        return r;
3487}
3488
3489int for_each_loose_file_in_objdir_buf(struct strbuf *path,
3490                            each_loose_object_fn obj_cb,
3491                            each_loose_cruft_fn cruft_cb,
3492                            each_loose_subdir_fn subdir_cb,
3493                            void *data)
3494{
3495        size_t baselen = path->len;
3496        int r = 0;
3497        int i;
3498
3499        for (i = 0; i < 256; i++) {
3500                strbuf_addf(path, "/%02x", i);
3501                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
3502                                                subdir_cb, data);
3503                strbuf_setlen(path, baselen);
3504                if (r)
3505                        break;
3506        }
3507
3508        return r;
3509}
3510
3511int for_each_loose_file_in_objdir(const char *path,
3512                                  each_loose_object_fn obj_cb,
3513                                  each_loose_cruft_fn cruft_cb,
3514                                  each_loose_subdir_fn subdir_cb,
3515                                  void *data)
3516{
3517        struct strbuf buf = STRBUF_INIT;
3518        int r;
3519
3520        strbuf_addstr(&buf, path);
3521        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
3522                                              subdir_cb, data);
3523        strbuf_release(&buf);
3524
3525        return r;
3526}
3527
3528struct loose_alt_odb_data {
3529        each_loose_object_fn *cb;
3530        void *data;
3531};
3532
3533static int loose_from_alt_odb(struct alternate_object_database *alt,
3534                              void *vdata)
3535{
3536        struct loose_alt_odb_data *data = vdata;
3537        struct strbuf buf = STRBUF_INIT;
3538        int r;
3539
3540        /* copy base not including trailing '/' */
3541        strbuf_add(&buf, alt->base, alt->name - alt->base - 1);
3542        r = for_each_loose_file_in_objdir_buf(&buf,
3543                                              data->cb, NULL, NULL,
3544                                              data->data);
3545        strbuf_release(&buf);
3546        return r;
3547}
3548
3549int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
3550{
3551        struct loose_alt_odb_data alt;
3552        int r;
3553
3554        r = for_each_loose_file_in_objdir(get_object_directory(),
3555                                          cb, NULL, NULL, data);
3556        if (r)
3557                return r;
3558
3559        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
3560                return 0;
3561
3562        alt.cb = cb;
3563        alt.data = data;
3564        return foreach_alt_odb(loose_from_alt_odb, &alt);
3565}
3566
3567static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
3568{
3569        uint32_t i;
3570        int r = 0;
3571
3572        for (i = 0; i < p->num_objects; i++) {
3573                const unsigned char *sha1 = nth_packed_object_sha1(p, i);
3574
3575                if (!sha1)
3576                        return error("unable to get sha1 of object %u in %s",
3577                                     i, p->pack_name);
3578
3579                r = cb(sha1, p, i, data);
3580                if (r)
3581                        break;
3582        }
3583        return r;
3584}
3585
3586int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
3587{
3588        struct packed_git *p;
3589        int r = 0;
3590        int pack_errors = 0;
3591
3592        prepare_packed_git();
3593        for (p = packed_git; p; p = p->next) {
3594                if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
3595                        continue;
3596                if (open_pack_index(p)) {
3597                        pack_errors = 1;
3598                        continue;
3599                }
3600                r = for_each_object_in_pack(p, cb, data);
3601                if (r)
3602                        break;
3603        }
3604        return r ? r : pack_errors;
3605}