sha1_file.con commit Merge branch 'rs/mailinfo-lib' into maint (71165f0)
   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
  27#ifndef O_NOATIME
  28#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
  29#define O_NOATIME 01000000
  30#else
  31#define O_NOATIME 0
  32#endif
  33#endif
  34
  35#define SZ_FMT PRIuMAX
  36static inline uintmax_t sz_fmt(size_t s) { return s; }
  37
  38const unsigned char null_sha1[20];
  39const struct object_id null_oid;
  40
  41/*
  42 * This is meant to hold a *small* number of objects that you would
  43 * want read_sha1_file() to be able to return, but yet you do not want
  44 * to write them into the object store (e.g. a browse-only
  45 * application).
  46 */
  47static struct cached_object {
  48        unsigned char sha1[20];
  49        enum object_type type;
  50        void *buf;
  51        unsigned long size;
  52} *cached_objects;
  53static int cached_object_nr, cached_object_alloc;
  54
  55static struct cached_object empty_tree = {
  56        EMPTY_TREE_SHA1_BIN_LITERAL,
  57        OBJ_TREE,
  58        "",
  59        0
  60};
  61
  62/*
  63 * A pointer to the last packed_git in which an object was found.
  64 * When an object is sought, we look in this packfile first, because
  65 * objects that are looked up at similar times are often in the same
  66 * packfile as one another.
  67 */
  68static struct packed_git *last_found_pack;
  69
  70static struct cached_object *find_cached_object(const unsigned char *sha1)
  71{
  72        int i;
  73        struct cached_object *co = cached_objects;
  74
  75        for (i = 0; i < cached_object_nr; i++, co++) {
  76                if (!hashcmp(co->sha1, sha1))
  77                        return co;
  78        }
  79        if (!hashcmp(sha1, empty_tree.sha1))
  80                return &empty_tree;
  81        return NULL;
  82}
  83
  84int mkdir_in_gitdir(const char *path)
  85{
  86        if (mkdir(path, 0777)) {
  87                int saved_errno = errno;
  88                struct stat st;
  89                struct strbuf sb = STRBUF_INIT;
  90
  91                if (errno != EEXIST)
  92                        return -1;
  93                /*
  94                 * Are we looking at a path in a symlinked worktree
  95                 * whose original repository does not yet have it?
  96                 * e.g. .git/rr-cache pointing at its original
  97                 * repository in which the user hasn't performed any
  98                 * conflict resolution yet?
  99                 */
 100                if (lstat(path, &st) || !S_ISLNK(st.st_mode) ||
 101                    strbuf_readlink(&sb, path, st.st_size) ||
 102                    !is_absolute_path(sb.buf) ||
 103                    mkdir(sb.buf, 0777)) {
 104                        strbuf_release(&sb);
 105                        errno = saved_errno;
 106                        return -1;
 107                }
 108                strbuf_release(&sb);
 109        }
 110        return adjust_shared_perm(path);
 111}
 112
 113enum scld_error safe_create_leading_directories(char *path)
 114{
 115        char *next_component = path + offset_1st_component(path);
 116        enum scld_error ret = SCLD_OK;
 117
 118        while (ret == SCLD_OK && next_component) {
 119                struct stat st;
 120                char *slash = next_component, slash_character;
 121
 122                while (*slash && !is_dir_sep(*slash))
 123                        slash++;
 124
 125                if (!*slash)
 126                        break;
 127
 128                next_component = slash + 1;
 129                while (is_dir_sep(*next_component))
 130                        next_component++;
 131                if (!*next_component)
 132                        break;
 133
 134                slash_character = *slash;
 135                *slash = '\0';
 136                if (!stat(path, &st)) {
 137                        /* path exists */
 138                        if (!S_ISDIR(st.st_mode))
 139                                ret = SCLD_EXISTS;
 140                } else if (mkdir(path, 0777)) {
 141                        if (errno == EEXIST &&
 142                            !stat(path, &st) && S_ISDIR(st.st_mode))
 143                                ; /* somebody created it since we checked */
 144                        else if (errno == ENOENT)
 145                                /*
 146                                 * Either mkdir() failed because
 147                                 * somebody just pruned the containing
 148                                 * directory, or stat() failed because
 149                                 * the file that was in our way was
 150                                 * just removed.  Either way, inform
 151                                 * the caller that it might be worth
 152                                 * trying again:
 153                                 */
 154                                ret = SCLD_VANISHED;
 155                        else
 156                                ret = SCLD_FAILED;
 157                } else if (adjust_shared_perm(path)) {
 158                        ret = SCLD_PERMS;
 159                }
 160                *slash = slash_character;
 161        }
 162        return ret;
 163}
 164
 165enum scld_error safe_create_leading_directories_const(const char *path)
 166{
 167        /* path points to cache entries, so xstrdup before messing with it */
 168        char *buf = xstrdup(path);
 169        enum scld_error result = safe_create_leading_directories(buf);
 170        free(buf);
 171        return result;
 172}
 173
 174static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 175{
 176        int i;
 177        for (i = 0; i < 20; i++) {
 178                static char hex[] = "0123456789abcdef";
 179                unsigned int val = sha1[i];
 180                char *pos = pathbuf + i*2 + (i > 0);
 181                *pos++ = hex[val >> 4];
 182                *pos = hex[val & 0xf];
 183        }
 184}
 185
 186const char *sha1_file_name(const unsigned char *sha1)
 187{
 188        static char buf[PATH_MAX];
 189        const char *objdir;
 190        int len;
 191
 192        objdir = get_object_directory();
 193        len = strlen(objdir);
 194
 195        /* '/' + sha1(2) + '/' + sha1(38) + '\0' */
 196        if (len + 43 > PATH_MAX)
 197                die("insanely long object directory %s", objdir);
 198        memcpy(buf, objdir, len);
 199        buf[len] = '/';
 200        buf[len+3] = '/';
 201        buf[len+42] = '\0';
 202        fill_sha1_path(buf + len + 1, sha1);
 203        return buf;
 204}
 205
 206/*
 207 * Return the name of the pack or index file with the specified sha1
 208 * in its filename.  *base and *name are scratch space that must be
 209 * provided by the caller.  which should be "pack" or "idx".
 210 */
 211static char *sha1_get_pack_name(const unsigned char *sha1,
 212                                struct strbuf *buf,
 213                                const char *which)
 214{
 215        strbuf_reset(buf);
 216        strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
 217                    sha1_to_hex(sha1), which);
 218        return buf->buf;
 219}
 220
 221char *sha1_pack_name(const unsigned char *sha1)
 222{
 223        static struct strbuf buf = STRBUF_INIT;
 224        return sha1_get_pack_name(sha1, &buf, "pack");
 225}
 226
 227char *sha1_pack_index_name(const unsigned char *sha1)
 228{
 229        static struct strbuf buf = STRBUF_INIT;
 230        return sha1_get_pack_name(sha1, &buf, "idx");
 231}
 232
 233struct alternate_object_database *alt_odb_list;
 234static struct alternate_object_database **alt_odb_tail;
 235
 236/*
 237 * Prepare alternate object database registry.
 238 *
 239 * The variable alt_odb_list points at the list of struct
 240 * alternate_object_database.  The elements on this list come from
 241 * non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
 242 * environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
 243 * whose contents is similar to that environment variable but can be
 244 * LF separated.  Its base points at a statically allocated buffer that
 245 * contains "/the/directory/corresponding/to/.git/objects/...", while
 246 * its name points just after the slash at the end of ".git/objects/"
 247 * in the example above, and has enough space to hold 40-byte hex
 248 * SHA1, an extra slash for the first level indirection, and the
 249 * terminating NUL.
 250 */
 251static int link_alt_odb_entry(const char *entry, const char *relative_base,
 252        int depth, const char *normalized_objdir)
 253{
 254        struct alternate_object_database *ent;
 255        struct alternate_object_database *alt;
 256        size_t pfxlen, entlen;
 257        struct strbuf pathbuf = STRBUF_INIT;
 258
 259        if (!is_absolute_path(entry) && relative_base) {
 260                strbuf_addstr(&pathbuf, real_path(relative_base));
 261                strbuf_addch(&pathbuf, '/');
 262        }
 263        strbuf_addstr(&pathbuf, entry);
 264
 265        normalize_path_copy(pathbuf.buf, pathbuf.buf);
 266
 267        pfxlen = strlen(pathbuf.buf);
 268
 269        /*
 270         * The trailing slash after the directory name is given by
 271         * this function at the end. Remove duplicates.
 272         */
 273        while (pfxlen && pathbuf.buf[pfxlen-1] == '/')
 274                pfxlen -= 1;
 275
 276        entlen = st_add(pfxlen, 43); /* '/' + 2 hex + '/' + 38 hex + NUL */
 277        ent = xmalloc(st_add(sizeof(*ent), entlen));
 278        memcpy(ent->base, pathbuf.buf, pfxlen);
 279        strbuf_release(&pathbuf);
 280
 281        ent->name = ent->base + pfxlen + 1;
 282        ent->base[pfxlen + 3] = '/';
 283        ent->base[pfxlen] = ent->base[entlen-1] = 0;
 284
 285        /* Detect cases where alternate disappeared */
 286        if (!is_directory(ent->base)) {
 287                error("object directory %s does not exist; "
 288                      "check .git/objects/info/alternates.",
 289                      ent->base);
 290                free(ent);
 291                return -1;
 292        }
 293
 294        /* Prevent the common mistake of listing the same
 295         * thing twice, or object directory itself.
 296         */
 297        for (alt = alt_odb_list; alt; alt = alt->next) {
 298                if (pfxlen == alt->name - alt->base - 1 &&
 299                    !memcmp(ent->base, alt->base, pfxlen)) {
 300                        free(ent);
 301                        return -1;
 302                }
 303        }
 304        if (!fspathcmp(ent->base, normalized_objdir)) {
 305                free(ent);
 306                return -1;
 307        }
 308
 309        /* add the alternate entry */
 310        *alt_odb_tail = ent;
 311        alt_odb_tail = &(ent->next);
 312        ent->next = NULL;
 313
 314        /* recursively add alternates */
 315        read_info_alternates(ent->base, depth + 1);
 316
 317        ent->base[pfxlen] = '/';
 318
 319        return 0;
 320}
 321
 322static void link_alt_odb_entries(const char *alt, int len, int sep,
 323                                 const char *relative_base, int depth)
 324{
 325        struct string_list entries = STRING_LIST_INIT_NODUP;
 326        char *alt_copy;
 327        int i;
 328        struct strbuf objdirbuf = STRBUF_INIT;
 329
 330        if (depth > 5) {
 331                error("%s: ignoring alternate object stores, nesting too deep.",
 332                                relative_base);
 333                return;
 334        }
 335
 336        strbuf_add_absolute_path(&objdirbuf, get_object_directory());
 337        normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
 338
 339        alt_copy = xmemdupz(alt, len);
 340        string_list_split_in_place(&entries, alt_copy, sep, -1);
 341        for (i = 0; i < entries.nr; i++) {
 342                const char *entry = entries.items[i].string;
 343                if (entry[0] == '\0' || entry[0] == '#')
 344                        continue;
 345                if (!is_absolute_path(entry) && depth) {
 346                        error("%s: ignoring relative alternate object store %s",
 347                                        relative_base, entry);
 348                } else {
 349                        link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
 350                }
 351        }
 352        string_list_clear(&entries, 0);
 353        free(alt_copy);
 354        strbuf_release(&objdirbuf);
 355}
 356
 357void read_info_alternates(const char * relative_base, int depth)
 358{
 359        char *map;
 360        size_t mapsz;
 361        struct stat st;
 362        char *path;
 363        int fd;
 364
 365        path = xstrfmt("%s/info/alternates", relative_base);
 366        fd = git_open_noatime(path);
 367        free(path);
 368        if (fd < 0)
 369                return;
 370        if (fstat(fd, &st) || (st.st_size == 0)) {
 371                close(fd);
 372                return;
 373        }
 374        mapsz = xsize_t(st.st_size);
 375        map = xmmap(NULL, mapsz, PROT_READ, MAP_PRIVATE, fd, 0);
 376        close(fd);
 377
 378        link_alt_odb_entries(map, mapsz, '\n', relative_base, depth);
 379
 380        munmap(map, mapsz);
 381}
 382
 383void add_to_alternates_file(const char *reference)
 384{
 385        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 386        char *alts = git_pathdup("objects/info/alternates");
 387        FILE *in, *out;
 388
 389        hold_lock_file_for_update(lock, alts, LOCK_DIE_ON_ERROR);
 390        out = fdopen_lock_file(lock, "w");
 391        if (!out)
 392                die_errno("unable to fdopen alternates lockfile");
 393
 394        in = fopen(alts, "r");
 395        if (in) {
 396                struct strbuf line = STRBUF_INIT;
 397                int found = 0;
 398
 399                while (strbuf_getline(&line, in) != EOF) {
 400                        if (!strcmp(reference, line.buf)) {
 401                                found = 1;
 402                                break;
 403                        }
 404                        fprintf_or_die(out, "%s\n", line.buf);
 405                }
 406
 407                strbuf_release(&line);
 408                fclose(in);
 409
 410                if (found) {
 411                        rollback_lock_file(lock);
 412                        lock = NULL;
 413                }
 414        }
 415        else if (errno != ENOENT)
 416                die_errno("unable to read alternates file");
 417
 418        if (lock) {
 419                fprintf_or_die(out, "%s\n", reference);
 420                if (commit_lock_file(lock))
 421                        die_errno("unable to move new alternates file into place");
 422                if (alt_odb_tail)
 423                        link_alt_odb_entries(reference, strlen(reference), '\n', NULL, 0);
 424        }
 425        free(alts);
 426}
 427
 428int foreach_alt_odb(alt_odb_fn fn, void *cb)
 429{
 430        struct alternate_object_database *ent;
 431        int r = 0;
 432
 433        prepare_alt_odb();
 434        for (ent = alt_odb_list; ent; ent = ent->next) {
 435                r = fn(ent, cb);
 436                if (r)
 437                        break;
 438        }
 439        return r;
 440}
 441
 442void prepare_alt_odb(void)
 443{
 444        const char *alt;
 445
 446        if (alt_odb_tail)
 447                return;
 448
 449        alt = getenv(ALTERNATE_DB_ENVIRONMENT);
 450        if (!alt) alt = "";
 451
 452        alt_odb_tail = &alt_odb_list;
 453        link_alt_odb_entries(alt, strlen(alt), PATH_SEP, NULL, 0);
 454
 455        read_info_alternates(get_object_directory(), 0);
 456}
 457
 458/* Returns 1 if we have successfully freshened the file, 0 otherwise. */
 459static int freshen_file(const char *fn)
 460{
 461        struct utimbuf t;
 462        t.actime = t.modtime = time(NULL);
 463        return !utime(fn, &t);
 464}
 465
 466/*
 467 * All of the check_and_freshen functions return 1 if the file exists and was
 468 * freshened (if freshening was requested), 0 otherwise. If they return
 469 * 0, you should not assume that it is safe to skip a write of the object (it
 470 * either does not exist on disk, or has a stale mtime and may be subject to
 471 * pruning).
 472 */
 473static int check_and_freshen_file(const char *fn, int freshen)
 474{
 475        if (access(fn, F_OK))
 476                return 0;
 477        if (freshen && !freshen_file(fn))
 478                return 0;
 479        return 1;
 480}
 481
 482static int check_and_freshen_local(const unsigned char *sha1, int freshen)
 483{
 484        return check_and_freshen_file(sha1_file_name(sha1), freshen);
 485}
 486
 487static int check_and_freshen_nonlocal(const unsigned char *sha1, int freshen)
 488{
 489        struct alternate_object_database *alt;
 490        prepare_alt_odb();
 491        for (alt = alt_odb_list; alt; alt = alt->next) {
 492                fill_sha1_path(alt->name, sha1);
 493                if (check_and_freshen_file(alt->base, freshen))
 494                        return 1;
 495        }
 496        return 0;
 497}
 498
 499static int check_and_freshen(const unsigned char *sha1, int freshen)
 500{
 501        return check_and_freshen_local(sha1, freshen) ||
 502               check_and_freshen_nonlocal(sha1, freshen);
 503}
 504
 505int has_loose_object_nonlocal(const unsigned char *sha1)
 506{
 507        return check_and_freshen_nonlocal(sha1, 0);
 508}
 509
 510static int has_loose_object(const unsigned char *sha1)
 511{
 512        return check_and_freshen(sha1, 0);
 513}
 514
 515static unsigned int pack_used_ctr;
 516static unsigned int pack_mmap_calls;
 517static unsigned int peak_pack_open_windows;
 518static unsigned int pack_open_windows;
 519static unsigned int pack_open_fds;
 520static unsigned int pack_max_fds;
 521static size_t peak_pack_mapped;
 522static size_t pack_mapped;
 523struct packed_git *packed_git;
 524
 525void pack_report(void)
 526{
 527        fprintf(stderr,
 528                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
 529                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
 530                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
 531                sz_fmt(getpagesize()),
 532                sz_fmt(packed_git_window_size),
 533                sz_fmt(packed_git_limit));
 534        fprintf(stderr,
 535                "pack_report: pack_used_ctr            = %10u\n"
 536                "pack_report: pack_mmap_calls          = %10u\n"
 537                "pack_report: pack_open_windows        = %10u / %10u\n"
 538                "pack_report: pack_mapped              = "
 539                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
 540                pack_used_ctr,
 541                pack_mmap_calls,
 542                pack_open_windows, peak_pack_open_windows,
 543                sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
 544}
 545
 546/*
 547 * Open and mmap the index file at path, perform a couple of
 548 * consistency checks, then record its information to p.  Return 0 on
 549 * success.
 550 */
 551static int check_packed_git_idx(const char *path, struct packed_git *p)
 552{
 553        void *idx_map;
 554        struct pack_idx_header *hdr;
 555        size_t idx_size;
 556        uint32_t version, nr, i, *index;
 557        int fd = git_open_noatime(path);
 558        struct stat st;
 559
 560        if (fd < 0)
 561                return -1;
 562        if (fstat(fd, &st)) {
 563                close(fd);
 564                return -1;
 565        }
 566        idx_size = xsize_t(st.st_size);
 567        if (idx_size < 4 * 256 + 20 + 20) {
 568                close(fd);
 569                return error("index file %s is too small", path);
 570        }
 571        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 572        close(fd);
 573
 574        hdr = idx_map;
 575        if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 576                version = ntohl(hdr->idx_version);
 577                if (version < 2 || version > 2) {
 578                        munmap(idx_map, idx_size);
 579                        return error("index file %s is version %"PRIu32
 580                                     " and is not supported by this binary"
 581                                     " (try upgrading GIT to a newer version)",
 582                                     path, version);
 583                }
 584        } else
 585                version = 1;
 586
 587        nr = 0;
 588        index = idx_map;
 589        if (version > 1)
 590                index += 2;  /* skip index header */
 591        for (i = 0; i < 256; i++) {
 592                uint32_t n = ntohl(index[i]);
 593                if (n < nr) {
 594                        munmap(idx_map, idx_size);
 595                        return error("non-monotonic index %s", path);
 596                }
 597                nr = n;
 598        }
 599
 600        if (version == 1) {
 601                /*
 602                 * Total size:
 603                 *  - 256 index entries 4 bytes each
 604                 *  - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
 605                 *  - 20-byte SHA1 of the packfile
 606                 *  - 20-byte SHA1 file checksum
 607                 */
 608                if (idx_size != 4*256 + nr * 24 + 20 + 20) {
 609                        munmap(idx_map, idx_size);
 610                        return error("wrong index v1 file size in %s", path);
 611                }
 612        } else if (version == 2) {
 613                /*
 614                 * Minimum size:
 615                 *  - 8 bytes of header
 616                 *  - 256 index entries 4 bytes each
 617                 *  - 20-byte sha1 entry * nr
 618                 *  - 4-byte crc entry * nr
 619                 *  - 4-byte offset entry * nr
 620                 *  - 20-byte SHA1 of the packfile
 621                 *  - 20-byte SHA1 file checksum
 622                 * And after the 4-byte offset table might be a
 623                 * variable sized table containing 8-byte entries
 624                 * for offsets larger than 2^31.
 625                 */
 626                unsigned long min_size = 8 + 4*256 + nr*(20 + 4 + 4) + 20 + 20;
 627                unsigned long max_size = min_size;
 628                if (nr)
 629                        max_size += (nr - 1)*8;
 630                if (idx_size < min_size || idx_size > max_size) {
 631                        munmap(idx_map, idx_size);
 632                        return error("wrong index v2 file size in %s", path);
 633                }
 634                if (idx_size != min_size &&
 635                    /*
 636                     * make sure we can deal with large pack offsets.
 637                     * 31-bit signed offset won't be enough, neither
 638                     * 32-bit unsigned one will be.
 639                     */
 640                    (sizeof(off_t) <= 4)) {
 641                        munmap(idx_map, idx_size);
 642                        return error("pack too large for current definition of off_t in %s", path);
 643                }
 644        }
 645
 646        p->index_version = version;
 647        p->index_data = idx_map;
 648        p->index_size = idx_size;
 649        p->num_objects = nr;
 650        return 0;
 651}
 652
 653int open_pack_index(struct packed_git *p)
 654{
 655        char *idx_name;
 656        size_t len;
 657        int ret;
 658
 659        if (p->index_data)
 660                return 0;
 661
 662        if (!strip_suffix(p->pack_name, ".pack", &len))
 663                die("BUG: pack_name does not end in .pack");
 664        idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 665        ret = check_packed_git_idx(idx_name, p);
 666        free(idx_name);
 667        return ret;
 668}
 669
 670static void scan_windows(struct packed_git *p,
 671        struct packed_git **lru_p,
 672        struct pack_window **lru_w,
 673        struct pack_window **lru_l)
 674{
 675        struct pack_window *w, *w_l;
 676
 677        for (w_l = NULL, w = p->windows; w; w = w->next) {
 678                if (!w->inuse_cnt) {
 679                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 680                                *lru_p = p;
 681                                *lru_w = w;
 682                                *lru_l = w_l;
 683                        }
 684                }
 685                w_l = w;
 686        }
 687}
 688
 689static int unuse_one_window(struct packed_git *current)
 690{
 691        struct packed_git *p, *lru_p = NULL;
 692        struct pack_window *lru_w = NULL, *lru_l = NULL;
 693
 694        if (current)
 695                scan_windows(current, &lru_p, &lru_w, &lru_l);
 696        for (p = packed_git; p; p = p->next)
 697                scan_windows(p, &lru_p, &lru_w, &lru_l);
 698        if (lru_p) {
 699                munmap(lru_w->base, lru_w->len);
 700                pack_mapped -= lru_w->len;
 701                if (lru_l)
 702                        lru_l->next = lru_w->next;
 703                else
 704                        lru_p->windows = lru_w->next;
 705                free(lru_w);
 706                pack_open_windows--;
 707                return 1;
 708        }
 709        return 0;
 710}
 711
 712void release_pack_memory(size_t need)
 713{
 714        size_t cur = pack_mapped;
 715        while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 716                ; /* nothing */
 717}
 718
 719static void mmap_limit_check(size_t length)
 720{
 721        static size_t limit = 0;
 722        if (!limit) {
 723                limit = git_env_ulong("GIT_MMAP_LIMIT", 0);
 724                if (!limit)
 725                        limit = SIZE_MAX;
 726        }
 727        if (length > limit)
 728                die("attempting to mmap %"PRIuMAX" over limit %"PRIuMAX,
 729                    (uintmax_t)length, (uintmax_t)limit);
 730}
 731
 732void *xmmap_gently(void *start, size_t length,
 733                  int prot, int flags, int fd, off_t offset)
 734{
 735        void *ret;
 736
 737        mmap_limit_check(length);
 738        ret = mmap(start, length, prot, flags, fd, offset);
 739        if (ret == MAP_FAILED) {
 740                if (!length)
 741                        return NULL;
 742                release_pack_memory(length);
 743                ret = mmap(start, length, prot, flags, fd, offset);
 744        }
 745        return ret;
 746}
 747
 748void *xmmap(void *start, size_t length,
 749        int prot, int flags, int fd, off_t offset)
 750{
 751        void *ret = xmmap_gently(start, length, prot, flags, fd, offset);
 752        if (ret == MAP_FAILED)
 753                die_errno("mmap failed");
 754        return ret;
 755}
 756
 757void close_pack_windows(struct packed_git *p)
 758{
 759        while (p->windows) {
 760                struct pack_window *w = p->windows;
 761
 762                if (w->inuse_cnt)
 763                        die("pack '%s' still has open windows to it",
 764                            p->pack_name);
 765                munmap(w->base, w->len);
 766                pack_mapped -= w->len;
 767                pack_open_windows--;
 768                p->windows = w->next;
 769                free(w);
 770        }
 771}
 772
 773static int close_pack_fd(struct packed_git *p)
 774{
 775        if (p->pack_fd < 0)
 776                return 0;
 777
 778        close(p->pack_fd);
 779        pack_open_fds--;
 780        p->pack_fd = -1;
 781
 782        return 1;
 783}
 784
 785static void close_pack(struct packed_git *p)
 786{
 787        close_pack_windows(p);
 788        close_pack_fd(p);
 789        close_pack_index(p);
 790}
 791
 792void close_all_packs(void)
 793{
 794        struct packed_git *p;
 795
 796        for (p = packed_git; p; p = p->next)
 797                if (p->do_not_close)
 798                        die("BUG! Want to close pack marked 'do-not-close'");
 799                else
 800                        close_pack(p);
 801}
 802
 803
 804/*
 805 * The LRU pack is the one with the oldest MRU window, preferring packs
 806 * with no used windows, or the oldest mtime if it has no windows allocated.
 807 */
 808static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 809{
 810        struct pack_window *w, *this_mru_w;
 811        int has_windows_inuse = 0;
 812
 813        /*
 814         * Reject this pack if it has windows and the previously selected
 815         * one does not.  If this pack does not have windows, reject
 816         * it if the pack file is newer than the previously selected one.
 817         */
 818        if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 819                return;
 820
 821        for (w = this_mru_w = p->windows; w; w = w->next) {
 822                /*
 823                 * Reject this pack if any of its windows are in use,
 824                 * but the previously selected pack did not have any
 825                 * inuse windows.  Otherwise, record that this pack
 826                 * has windows in use.
 827                 */
 828                if (w->inuse_cnt) {
 829                        if (*accept_windows_inuse)
 830                                has_windows_inuse = 1;
 831                        else
 832                                return;
 833                }
 834
 835                if (w->last_used > this_mru_w->last_used)
 836                        this_mru_w = w;
 837
 838                /*
 839                 * Reject this pack if it has windows that have been
 840                 * used more recently than the previously selected pack.
 841                 * If the previously selected pack had windows inuse and
 842                 * we have not encountered a window in this pack that is
 843                 * inuse, skip this check since we prefer a pack with no
 844                 * inuse windows to one that has inuse windows.
 845                 */
 846                if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 847                    this_mru_w->last_used > (*mru_w)->last_used)
 848                        return;
 849        }
 850
 851        /*
 852         * Select this pack.
 853         */
 854        *mru_w = this_mru_w;
 855        *lru_p = p;
 856        *accept_windows_inuse = has_windows_inuse;
 857}
 858
 859static int close_one_pack(void)
 860{
 861        struct packed_git *p, *lru_p = NULL;
 862        struct pack_window *mru_w = NULL;
 863        int accept_windows_inuse = 1;
 864
 865        for (p = packed_git; p; p = p->next) {
 866                if (p->pack_fd == -1)
 867                        continue;
 868                find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 869        }
 870
 871        if (lru_p)
 872                return close_pack_fd(lru_p);
 873
 874        return 0;
 875}
 876
 877void unuse_pack(struct pack_window **w_cursor)
 878{
 879        struct pack_window *w = *w_cursor;
 880        if (w) {
 881                w->inuse_cnt--;
 882                *w_cursor = NULL;
 883        }
 884}
 885
 886void close_pack_index(struct packed_git *p)
 887{
 888        if (p->index_data) {
 889                munmap((void *)p->index_data, p->index_size);
 890                p->index_data = NULL;
 891        }
 892}
 893
 894/*
 895 * This is used by git-repack in case a newly created pack happens to
 896 * contain the same set of objects as an existing one.  In that case
 897 * the resulting file might be different even if its name would be the
 898 * same.  It is best to close any reference to the old pack before it is
 899 * replaced on disk.  Of course no index pointers or windows for given pack
 900 * must subsist at this point.  If ever objects from this pack are requested
 901 * again, the new version of the pack will be reinitialized through
 902 * reprepare_packed_git().
 903 */
 904void free_pack_by_name(const char *pack_name)
 905{
 906        struct packed_git *p, **pp = &packed_git;
 907
 908        while (*pp) {
 909                p = *pp;
 910                if (strcmp(pack_name, p->pack_name) == 0) {
 911                        clear_delta_base_cache();
 912                        close_pack(p);
 913                        free(p->bad_object_sha1);
 914                        *pp = p->next;
 915                        if (last_found_pack == p)
 916                                last_found_pack = NULL;
 917                        free(p);
 918                        return;
 919                }
 920                pp = &p->next;
 921        }
 922}
 923
 924static unsigned int get_max_fd_limit(void)
 925{
 926#ifdef RLIMIT_NOFILE
 927        {
 928                struct rlimit lim;
 929
 930                if (!getrlimit(RLIMIT_NOFILE, &lim))
 931                        return lim.rlim_cur;
 932        }
 933#endif
 934
 935#ifdef _SC_OPEN_MAX
 936        {
 937                long open_max = sysconf(_SC_OPEN_MAX);
 938                if (0 < open_max)
 939                        return open_max;
 940                /*
 941                 * Otherwise, we got -1 for one of the two
 942                 * reasons:
 943                 *
 944                 * (1) sysconf() did not understand _SC_OPEN_MAX
 945                 *     and signaled an error with -1; or
 946                 * (2) sysconf() said there is no limit.
 947                 *
 948                 * We _could_ clear errno before calling sysconf() to
 949                 * tell these two cases apart and return a huge number
 950                 * in the latter case to let the caller cap it to a
 951                 * value that is not so selfish, but letting the
 952                 * fallback OPEN_MAX codepath take care of these cases
 953                 * is a lot simpler.
 954                 */
 955        }
 956#endif
 957
 958#ifdef OPEN_MAX
 959        return OPEN_MAX;
 960#else
 961        return 1; /* see the caller ;-) */
 962#endif
 963}
 964
 965/*
 966 * Do not call this directly as this leaks p->pack_fd on error return;
 967 * call open_packed_git() instead.
 968 */
 969static int open_packed_git_1(struct packed_git *p)
 970{
 971        struct stat st;
 972        struct pack_header hdr;
 973        unsigned char sha1[20];
 974        unsigned char *idx_sha1;
 975        long fd_flag;
 976
 977        if (!p->index_data && open_pack_index(p))
 978                return error("packfile %s index unavailable", p->pack_name);
 979
 980        if (!pack_max_fds) {
 981                unsigned int max_fds = get_max_fd_limit();
 982
 983                /* Save 3 for stdin/stdout/stderr, 22 for work */
 984                if (25 < max_fds)
 985                        pack_max_fds = max_fds - 25;
 986                else
 987                        pack_max_fds = 1;
 988        }
 989
 990        while (pack_max_fds <= pack_open_fds && close_one_pack())
 991                ; /* nothing */
 992
 993        p->pack_fd = git_open_noatime(p->pack_name);
 994        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 995                return -1;
 996        pack_open_fds++;
 997
 998        /* If we created the struct before we had the pack we lack size. */
 999        if (!p->pack_size) {
1000                if (!S_ISREG(st.st_mode))
1001                        return error("packfile %s not a regular file", p->pack_name);
1002                p->pack_size = st.st_size;
1003        } else if (p->pack_size != st.st_size)
1004                return error("packfile %s size changed", p->pack_name);
1005
1006        /* We leave these file descriptors open with sliding mmap;
1007         * there is no point keeping them open across exec(), though.
1008         */
1009        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
1010        if (fd_flag < 0)
1011                return error("cannot determine file descriptor flags");
1012        fd_flag |= FD_CLOEXEC;
1013        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
1014                return error("cannot set FD_CLOEXEC");
1015
1016        /* Verify we recognize this pack file format. */
1017        if (read_in_full(p->pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
1018                return error("file %s is far too short to be a packfile", p->pack_name);
1019        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
1020                return error("file %s is not a GIT packfile", p->pack_name);
1021        if (!pack_version_ok(hdr.hdr_version))
1022                return error("packfile %s is version %"PRIu32" and not"
1023                        " supported (try upgrading GIT to a newer version)",
1024                        p->pack_name, ntohl(hdr.hdr_version));
1025
1026        /* Verify the pack matches its index. */
1027        if (p->num_objects != ntohl(hdr.hdr_entries))
1028                return error("packfile %s claims to have %"PRIu32" objects"
1029                             " while index indicates %"PRIu32" objects",
1030                             p->pack_name, ntohl(hdr.hdr_entries),
1031                             p->num_objects);
1032        if (lseek(p->pack_fd, p->pack_size - sizeof(sha1), SEEK_SET) == -1)
1033                return error("end of packfile %s is unavailable", p->pack_name);
1034        if (read_in_full(p->pack_fd, sha1, sizeof(sha1)) != sizeof(sha1))
1035                return error("packfile %s signature is unavailable", p->pack_name);
1036        idx_sha1 = ((unsigned char *)p->index_data) + p->index_size - 40;
1037        if (hashcmp(sha1, idx_sha1))
1038                return error("packfile %s does not match index", p->pack_name);
1039        return 0;
1040}
1041
1042static int open_packed_git(struct packed_git *p)
1043{
1044        if (!open_packed_git_1(p))
1045                return 0;
1046        close_pack_fd(p);
1047        return -1;
1048}
1049
1050static int in_window(struct pack_window *win, off_t offset)
1051{
1052        /* We must promise at least 20 bytes (one hash) after the
1053         * offset is available from this window, otherwise the offset
1054         * is not actually in this window and a different window (which
1055         * has that one hash excess) must be used.  This is to support
1056         * the object header and delta base parsing routines below.
1057         */
1058        off_t win_off = win->offset;
1059        return win_off <= offset
1060                && (offset + 20) <= (win_off + win->len);
1061}
1062
1063unsigned char *use_pack(struct packed_git *p,
1064                struct pack_window **w_cursor,
1065                off_t offset,
1066                unsigned long *left)
1067{
1068        struct pack_window *win = *w_cursor;
1069
1070        /* Since packfiles end in a hash of their content and it's
1071         * pointless to ask for an offset into the middle of that
1072         * hash, and the in_window function above wouldn't match
1073         * don't allow an offset too close to the end of the file.
1074         */
1075        if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
1076                die("packfile %s cannot be accessed", p->pack_name);
1077        if (offset > (p->pack_size - 20))
1078                die("offset beyond end of packfile (truncated pack?)");
1079        if (offset < 0)
1080                die(_("offset before end of packfile (broken .idx?)"));
1081
1082        if (!win || !in_window(win, offset)) {
1083                if (win)
1084                        win->inuse_cnt--;
1085                for (win = p->windows; win; win = win->next) {
1086                        if (in_window(win, offset))
1087                                break;
1088                }
1089                if (!win) {
1090                        size_t window_align = packed_git_window_size / 2;
1091                        off_t len;
1092
1093                        if (p->pack_fd == -1 && open_packed_git(p))
1094                                die("packfile %s cannot be accessed", p->pack_name);
1095
1096                        win = xcalloc(1, sizeof(*win));
1097                        win->offset = (offset / window_align) * window_align;
1098                        len = p->pack_size - win->offset;
1099                        if (len > packed_git_window_size)
1100                                len = packed_git_window_size;
1101                        win->len = (size_t)len;
1102                        pack_mapped += win->len;
1103                        while (packed_git_limit < pack_mapped
1104                                && unuse_one_window(p))
1105                                ; /* nothing */
1106                        win->base = xmmap(NULL, win->len,
1107                                PROT_READ, MAP_PRIVATE,
1108                                p->pack_fd, win->offset);
1109                        if (win->base == MAP_FAILED)
1110                                die_errno("packfile %s cannot be mapped",
1111                                          p->pack_name);
1112                        if (!win->offset && win->len == p->pack_size
1113                                && !p->do_not_close)
1114                                close_pack_fd(p);
1115                        pack_mmap_calls++;
1116                        pack_open_windows++;
1117                        if (pack_mapped > peak_pack_mapped)
1118                                peak_pack_mapped = pack_mapped;
1119                        if (pack_open_windows > peak_pack_open_windows)
1120                                peak_pack_open_windows = pack_open_windows;
1121                        win->next = p->windows;
1122                        p->windows = win;
1123                }
1124        }
1125        if (win != *w_cursor) {
1126                win->last_used = pack_used_ctr++;
1127                win->inuse_cnt++;
1128                *w_cursor = win;
1129        }
1130        offset -= win->offset;
1131        if (left)
1132                *left = win->len - xsize_t(offset);
1133        return win->base + offset;
1134}
1135
1136static struct packed_git *alloc_packed_git(int extra)
1137{
1138        struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
1139        memset(p, 0, sizeof(*p));
1140        p->pack_fd = -1;
1141        return p;
1142}
1143
1144static void try_to_free_pack_memory(size_t size)
1145{
1146        release_pack_memory(size);
1147}
1148
1149struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
1150{
1151        static int have_set_try_to_free_routine;
1152        struct stat st;
1153        size_t alloc;
1154        struct packed_git *p;
1155
1156        if (!have_set_try_to_free_routine) {
1157                have_set_try_to_free_routine = 1;
1158                set_try_to_free_routine(try_to_free_pack_memory);
1159        }
1160
1161        /*
1162         * Make sure a corresponding .pack file exists and that
1163         * the index looks sane.
1164         */
1165        if (!strip_suffix_mem(path, &path_len, ".idx"))
1166                return NULL;
1167
1168        /*
1169         * ".pack" is long enough to hold any suffix we're adding (and
1170         * the use xsnprintf double-checks that)
1171         */
1172        alloc = st_add3(path_len, strlen(".pack"), 1);
1173        p = alloc_packed_git(alloc);
1174        memcpy(p->pack_name, path, path_len);
1175
1176        xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
1177        if (!access(p->pack_name, F_OK))
1178                p->pack_keep = 1;
1179
1180        xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
1181        if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
1182                free(p);
1183                return NULL;
1184        }
1185
1186        /* ok, it looks sane as far as we can check without
1187         * actually mapping the pack file.
1188         */
1189        p->pack_size = st.st_size;
1190        p->pack_local = local;
1191        p->mtime = st.st_mtime;
1192        if (path_len < 40 || get_sha1_hex(path + path_len - 40, p->sha1))
1193                hashclr(p->sha1);
1194        return p;
1195}
1196
1197struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
1198{
1199        const char *path = sha1_pack_name(sha1);
1200        size_t alloc = st_add(strlen(path), 1);
1201        struct packed_git *p = alloc_packed_git(alloc);
1202
1203        memcpy(p->pack_name, path, alloc); /* includes NUL */
1204        hashcpy(p->sha1, sha1);
1205        if (check_packed_git_idx(idx_path, p)) {
1206                free(p);
1207                return NULL;
1208        }
1209
1210        return p;
1211}
1212
1213void install_packed_git(struct packed_git *pack)
1214{
1215        if (pack->pack_fd != -1)
1216                pack_open_fds++;
1217
1218        pack->next = packed_git;
1219        packed_git = pack;
1220}
1221
1222void (*report_garbage)(unsigned seen_bits, const char *path);
1223
1224static void report_helper(const struct string_list *list,
1225                          int seen_bits, int first, int last)
1226{
1227        if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
1228                return;
1229
1230        for (; first < last; first++)
1231                report_garbage(seen_bits, list->items[first].string);
1232}
1233
1234static void report_pack_garbage(struct string_list *list)
1235{
1236        int i, baselen = -1, first = 0, seen_bits = 0;
1237
1238        if (!report_garbage)
1239                return;
1240
1241        string_list_sort(list);
1242
1243        for (i = 0; i < list->nr; i++) {
1244                const char *path = list->items[i].string;
1245                if (baselen != -1 &&
1246                    strncmp(path, list->items[first].string, baselen)) {
1247                        report_helper(list, seen_bits, first, i);
1248                        baselen = -1;
1249                        seen_bits = 0;
1250                }
1251                if (baselen == -1) {
1252                        const char *dot = strrchr(path, '.');
1253                        if (!dot) {
1254                                report_garbage(PACKDIR_FILE_GARBAGE, path);
1255                                continue;
1256                        }
1257                        baselen = dot - path + 1;
1258                        first = i;
1259                }
1260                if (!strcmp(path + baselen, "pack"))
1261                        seen_bits |= 1;
1262                else if (!strcmp(path + baselen, "idx"))
1263                        seen_bits |= 2;
1264        }
1265        report_helper(list, seen_bits, first, list->nr);
1266}
1267
1268static void prepare_packed_git_one(char *objdir, int local)
1269{
1270        struct strbuf path = STRBUF_INIT;
1271        size_t dirnamelen;
1272        DIR *dir;
1273        struct dirent *de;
1274        struct string_list garbage = STRING_LIST_INIT_DUP;
1275
1276        strbuf_addstr(&path, objdir);
1277        strbuf_addstr(&path, "/pack");
1278        dir = opendir(path.buf);
1279        if (!dir) {
1280                if (errno != ENOENT)
1281                        error_errno("unable to open object pack directory: %s",
1282                                    path.buf);
1283                strbuf_release(&path);
1284                return;
1285        }
1286        strbuf_addch(&path, '/');
1287        dirnamelen = path.len;
1288        while ((de = readdir(dir)) != NULL) {
1289                struct packed_git *p;
1290                size_t base_len;
1291
1292                if (is_dot_or_dotdot(de->d_name))
1293                        continue;
1294
1295                strbuf_setlen(&path, dirnamelen);
1296                strbuf_addstr(&path, de->d_name);
1297
1298                base_len = path.len;
1299                if (strip_suffix_mem(path.buf, &base_len, ".idx")) {
1300                        /* Don't reopen a pack we already have. */
1301                        for (p = packed_git; p; p = p->next) {
1302                                size_t len;
1303                                if (strip_suffix(p->pack_name, ".pack", &len) &&
1304                                    len == base_len &&
1305                                    !memcmp(p->pack_name, path.buf, len))
1306                                        break;
1307                        }
1308                        if (p == NULL &&
1309                            /*
1310                             * See if it really is a valid .idx file with
1311                             * corresponding .pack file that we can map.
1312                             */
1313                            (p = add_packed_git(path.buf, path.len, local)) != NULL)
1314                                install_packed_git(p);
1315                }
1316
1317                if (!report_garbage)
1318                        continue;
1319
1320                if (ends_with(de->d_name, ".idx") ||
1321                    ends_with(de->d_name, ".pack") ||
1322                    ends_with(de->d_name, ".bitmap") ||
1323                    ends_with(de->d_name, ".keep"))
1324                        string_list_append(&garbage, path.buf);
1325                else
1326                        report_garbage(PACKDIR_FILE_GARBAGE, path.buf);
1327        }
1328        closedir(dir);
1329        report_pack_garbage(&garbage);
1330        string_list_clear(&garbage, 0);
1331        strbuf_release(&path);
1332}
1333
1334static int sort_pack(const void *a_, const void *b_)
1335{
1336        struct packed_git *a = *((struct packed_git **)a_);
1337        struct packed_git *b = *((struct packed_git **)b_);
1338        int st;
1339
1340        /*
1341         * Local packs tend to contain objects specific to our
1342         * variant of the project than remote ones.  In addition,
1343         * remote ones could be on a network mounted filesystem.
1344         * Favor local ones for these reasons.
1345         */
1346        st = a->pack_local - b->pack_local;
1347        if (st)
1348                return -st;
1349
1350        /*
1351         * Younger packs tend to contain more recent objects,
1352         * and more recent objects tend to get accessed more
1353         * often.
1354         */
1355        if (a->mtime < b->mtime)
1356                return 1;
1357        else if (a->mtime == b->mtime)
1358                return 0;
1359        return -1;
1360}
1361
1362static void rearrange_packed_git(void)
1363{
1364        struct packed_git **ary, *p;
1365        int i, n;
1366
1367        for (n = 0, p = packed_git; p; p = p->next)
1368                n++;
1369        if (n < 2)
1370                return;
1371
1372        /* prepare an array of packed_git for easier sorting */
1373        ary = xcalloc(n, sizeof(struct packed_git *));
1374        for (n = 0, p = packed_git; p; p = p->next)
1375                ary[n++] = p;
1376
1377        qsort(ary, n, sizeof(struct packed_git *), sort_pack);
1378
1379        /* link them back again */
1380        for (i = 0; i < n - 1; i++)
1381                ary[i]->next = ary[i + 1];
1382        ary[n - 1]->next = NULL;
1383        packed_git = ary[0];
1384
1385        free(ary);
1386}
1387
1388static int prepare_packed_git_run_once = 0;
1389void prepare_packed_git(void)
1390{
1391        struct alternate_object_database *alt;
1392
1393        if (prepare_packed_git_run_once)
1394                return;
1395        prepare_packed_git_one(get_object_directory(), 1);
1396        prepare_alt_odb();
1397        for (alt = alt_odb_list; alt; alt = alt->next) {
1398                alt->name[-1] = 0;
1399                prepare_packed_git_one(alt->base, 0);
1400                alt->name[-1] = '/';
1401        }
1402        rearrange_packed_git();
1403        prepare_packed_git_run_once = 1;
1404}
1405
1406void reprepare_packed_git(void)
1407{
1408        prepare_packed_git_run_once = 0;
1409        prepare_packed_git();
1410}
1411
1412static void mark_bad_packed_object(struct packed_git *p,
1413                                   const unsigned char *sha1)
1414{
1415        unsigned i;
1416        for (i = 0; i < p->num_bad_objects; i++)
1417                if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1418                        return;
1419        p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1420                                      st_mult(GIT_SHA1_RAWSZ,
1421                                              st_add(p->num_bad_objects, 1)));
1422        hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1423        p->num_bad_objects++;
1424}
1425
1426static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1427{
1428        struct packed_git *p;
1429        unsigned i;
1430
1431        for (p = packed_git; p; p = p->next)
1432                for (i = 0; i < p->num_bad_objects; i++)
1433                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
1434                                return p;
1435        return NULL;
1436}
1437
1438/*
1439 * With an in-core object data in "map", rehash it to make sure the
1440 * object name actually matches "sha1" to detect object corruption.
1441 * With "map" == NULL, try reading the object named with "sha1" using
1442 * the streaming interface and rehash it to do the same.
1443 */
1444int check_sha1_signature(const unsigned char *sha1, void *map,
1445                         unsigned long size, const char *type)
1446{
1447        unsigned char real_sha1[20];
1448        enum object_type obj_type;
1449        struct git_istream *st;
1450        git_SHA_CTX c;
1451        char hdr[32];
1452        int hdrlen;
1453
1454        if (map) {
1455                hash_sha1_file(map, size, type, real_sha1);
1456                return hashcmp(sha1, real_sha1) ? -1 : 0;
1457        }
1458
1459        st = open_istream(sha1, &obj_type, &size, NULL);
1460        if (!st)
1461                return -1;
1462
1463        /* Generate the header */
1464        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(obj_type), size) + 1;
1465
1466        /* Sha1.. */
1467        git_SHA1_Init(&c);
1468        git_SHA1_Update(&c, hdr, hdrlen);
1469        for (;;) {
1470                char buf[1024 * 16];
1471                ssize_t readlen = read_istream(st, buf, sizeof(buf));
1472
1473                if (readlen < 0) {
1474                        close_istream(st);
1475                        return -1;
1476                }
1477                if (!readlen)
1478                        break;
1479                git_SHA1_Update(&c, buf, readlen);
1480        }
1481        git_SHA1_Final(real_sha1, &c);
1482        close_istream(st);
1483        return hashcmp(sha1, real_sha1) ? -1 : 0;
1484}
1485
1486int git_open_noatime(const char *name)
1487{
1488        static int sha1_file_open_flag = O_NOATIME;
1489
1490        for (;;) {
1491                int fd;
1492
1493                errno = 0;
1494                fd = open(name, O_RDONLY | sha1_file_open_flag);
1495                if (fd >= 0)
1496                        return fd;
1497
1498                /* Might the failure be due to O_NOATIME? */
1499                if (errno != ENOENT && sha1_file_open_flag) {
1500                        sha1_file_open_flag = 0;
1501                        continue;
1502                }
1503
1504                return -1;
1505        }
1506}
1507
1508static int stat_sha1_file(const unsigned char *sha1, struct stat *st)
1509{
1510        struct alternate_object_database *alt;
1511
1512        if (!lstat(sha1_file_name(sha1), st))
1513                return 0;
1514
1515        prepare_alt_odb();
1516        errno = ENOENT;
1517        for (alt = alt_odb_list; alt; alt = alt->next) {
1518                fill_sha1_path(alt->name, sha1);
1519                if (!lstat(alt->base, st))
1520                        return 0;
1521        }
1522
1523        return -1;
1524}
1525
1526static int open_sha1_file(const unsigned char *sha1)
1527{
1528        int fd;
1529        struct alternate_object_database *alt;
1530        int most_interesting_errno;
1531
1532        fd = git_open_noatime(sha1_file_name(sha1));
1533        if (fd >= 0)
1534                return fd;
1535        most_interesting_errno = errno;
1536
1537        prepare_alt_odb();
1538        for (alt = alt_odb_list; alt; alt = alt->next) {
1539                fill_sha1_path(alt->name, sha1);
1540                fd = git_open_noatime(alt->base);
1541                if (fd >= 0)
1542                        return fd;
1543                if (most_interesting_errno == ENOENT)
1544                        most_interesting_errno = errno;
1545        }
1546        errno = most_interesting_errno;
1547        return -1;
1548}
1549
1550void *map_sha1_file(const unsigned char *sha1, unsigned long *size)
1551{
1552        void *map;
1553        int fd;
1554
1555        fd = open_sha1_file(sha1);
1556        map = NULL;
1557        if (fd >= 0) {
1558                struct stat st;
1559
1560                if (!fstat(fd, &st)) {
1561                        *size = xsize_t(st.st_size);
1562                        if (!*size) {
1563                                /* mmap() is forbidden on empty files */
1564                                error("object file %s is empty", sha1_file_name(sha1));
1565                                return NULL;
1566                        }
1567                        map = xmmap(NULL, *size, PROT_READ, MAP_PRIVATE, fd, 0);
1568                }
1569                close(fd);
1570        }
1571        return map;
1572}
1573
1574unsigned long unpack_object_header_buffer(const unsigned char *buf,
1575                unsigned long len, enum object_type *type, unsigned long *sizep)
1576{
1577        unsigned shift;
1578        unsigned long size, c;
1579        unsigned long used = 0;
1580
1581        c = buf[used++];
1582        *type = (c >> 4) & 7;
1583        size = c & 15;
1584        shift = 4;
1585        while (c & 0x80) {
1586                if (len <= used || bitsizeof(long) <= shift) {
1587                        error("bad object header");
1588                        size = used = 0;
1589                        break;
1590                }
1591                c = buf[used++];
1592                size += (c & 0x7f) << shift;
1593                shift += 7;
1594        }
1595        *sizep = size;
1596        return used;
1597}
1598
1599int unpack_sha1_header(git_zstream *stream, unsigned char *map, unsigned long mapsize, void *buffer, unsigned long bufsiz)
1600{
1601        /* Get the data stream */
1602        memset(stream, 0, sizeof(*stream));
1603        stream->next_in = map;
1604        stream->avail_in = mapsize;
1605        stream->next_out = buffer;
1606        stream->avail_out = bufsiz;
1607
1608        git_inflate_init(stream);
1609        return git_inflate(stream, 0);
1610}
1611
1612static int unpack_sha1_header_to_strbuf(git_zstream *stream, unsigned char *map,
1613                                        unsigned long mapsize, void *buffer,
1614                                        unsigned long bufsiz, struct strbuf *header)
1615{
1616        int status;
1617
1618        status = unpack_sha1_header(stream, map, mapsize, buffer, bufsiz);
1619
1620        /*
1621         * Check if entire header is unpacked in the first iteration.
1622         */
1623        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1624                return 0;
1625
1626        /*
1627         * buffer[0..bufsiz] was not large enough.  Copy the partial
1628         * result out to header, and then append the result of further
1629         * reading the stream.
1630         */
1631        strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1632        stream->next_out = buffer;
1633        stream->avail_out = bufsiz;
1634
1635        do {
1636                status = git_inflate(stream, 0);
1637                strbuf_add(header, buffer, stream->next_out - (unsigned char *)buffer);
1638                if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
1639                        return 0;
1640                stream->next_out = buffer;
1641                stream->avail_out = bufsiz;
1642        } while (status != Z_STREAM_END);
1643        return -1;
1644}
1645
1646static void *unpack_sha1_rest(git_zstream *stream, void *buffer, unsigned long size, const unsigned char *sha1)
1647{
1648        int bytes = strlen(buffer) + 1;
1649        unsigned char *buf = xmallocz(size);
1650        unsigned long n;
1651        int status = Z_OK;
1652
1653        n = stream->total_out - bytes;
1654        if (n > size)
1655                n = size;
1656        memcpy(buf, (char *) buffer + bytes, n);
1657        bytes = n;
1658        if (bytes <= size) {
1659                /*
1660                 * The above condition must be (bytes <= size), not
1661                 * (bytes < size).  In other words, even though we
1662                 * expect no more output and set avail_out to zero,
1663                 * the input zlib stream may have bytes that express
1664                 * "this concludes the stream", and we *do* want to
1665                 * eat that input.
1666                 *
1667                 * Otherwise we would not be able to test that we
1668                 * consumed all the input to reach the expected size;
1669                 * we also want to check that zlib tells us that all
1670                 * went well with status == Z_STREAM_END at the end.
1671                 */
1672                stream->next_out = buf + bytes;
1673                stream->avail_out = size - bytes;
1674                while (status == Z_OK)
1675                        status = git_inflate(stream, Z_FINISH);
1676        }
1677        if (status == Z_STREAM_END && !stream->avail_in) {
1678                git_inflate_end(stream);
1679                return buf;
1680        }
1681
1682        if (status < 0)
1683                error("corrupt loose object '%s'", sha1_to_hex(sha1));
1684        else if (stream->avail_in)
1685                error("garbage at end of loose object '%s'",
1686                      sha1_to_hex(sha1));
1687        free(buf);
1688        return NULL;
1689}
1690
1691/*
1692 * We used to just use "sscanf()", but that's actually way
1693 * too permissive for what we want to check. So do an anal
1694 * object header parse by hand.
1695 */
1696static int parse_sha1_header_extended(const char *hdr, struct object_info *oi,
1697                               unsigned int flags)
1698{
1699        const char *type_buf = hdr;
1700        unsigned long size;
1701        int type, type_len = 0;
1702
1703        /*
1704         * The type can be of any size but is followed by
1705         * a space.
1706         */
1707        for (;;) {
1708                char c = *hdr++;
1709                if (c == ' ')
1710                        break;
1711                type_len++;
1712        }
1713
1714        type = type_from_string_gently(type_buf, type_len, 1);
1715        if (oi->typename)
1716                strbuf_add(oi->typename, type_buf, type_len);
1717        /*
1718         * Set type to 0 if its an unknown object and
1719         * we're obtaining the type using '--allow-unkown-type'
1720         * option.
1721         */
1722        if ((flags & LOOKUP_UNKNOWN_OBJECT) && (type < 0))
1723                type = 0;
1724        else if (type < 0)
1725                die("invalid object type");
1726        if (oi->typep)
1727                *oi->typep = type;
1728
1729        /*
1730         * The length must follow immediately, and be in canonical
1731         * decimal format (ie "010" is not valid).
1732         */
1733        size = *hdr++ - '0';
1734        if (size > 9)
1735                return -1;
1736        if (size) {
1737                for (;;) {
1738                        unsigned long c = *hdr - '0';
1739                        if (c > 9)
1740                                break;
1741                        hdr++;
1742                        size = size * 10 + c;
1743                }
1744        }
1745
1746        if (oi->sizep)
1747                *oi->sizep = size;
1748
1749        /*
1750         * The length must be followed by a zero byte
1751         */
1752        return *hdr ? -1 : type;
1753}
1754
1755int parse_sha1_header(const char *hdr, unsigned long *sizep)
1756{
1757        struct object_info oi;
1758
1759        oi.sizep = sizep;
1760        oi.typename = NULL;
1761        oi.typep = NULL;
1762        return parse_sha1_header_extended(hdr, &oi, LOOKUP_REPLACE_OBJECT);
1763}
1764
1765static void *unpack_sha1_file(void *map, unsigned long mapsize, enum object_type *type, unsigned long *size, const unsigned char *sha1)
1766{
1767        int ret;
1768        git_zstream stream;
1769        char hdr[8192];
1770
1771        ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
1772        if (ret < Z_OK || (*type = parse_sha1_header(hdr, size)) < 0)
1773                return NULL;
1774
1775        return unpack_sha1_rest(&stream, hdr, *size, sha1);
1776}
1777
1778unsigned long get_size_from_delta(struct packed_git *p,
1779                                  struct pack_window **w_curs,
1780                                  off_t curpos)
1781{
1782        const unsigned char *data;
1783        unsigned char delta_head[20], *in;
1784        git_zstream stream;
1785        int st;
1786
1787        memset(&stream, 0, sizeof(stream));
1788        stream.next_out = delta_head;
1789        stream.avail_out = sizeof(delta_head);
1790
1791        git_inflate_init(&stream);
1792        do {
1793                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1794                stream.next_in = in;
1795                st = git_inflate(&stream, Z_FINISH);
1796                curpos += stream.next_in - in;
1797        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1798                 stream.total_out < sizeof(delta_head));
1799        git_inflate_end(&stream);
1800        if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1801                error("delta data unpack-initial failed");
1802                return 0;
1803        }
1804
1805        /* Examine the initial part of the delta to figure out
1806         * the result size.
1807         */
1808        data = delta_head;
1809
1810        /* ignore base size */
1811        get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1812
1813        /* Read the result size */
1814        return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1815}
1816
1817static off_t get_delta_base(struct packed_git *p,
1818                                    struct pack_window **w_curs,
1819                                    off_t *curpos,
1820                                    enum object_type type,
1821                                    off_t delta_obj_offset)
1822{
1823        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1824        off_t base_offset;
1825
1826        /* use_pack() assured us we have [base_info, base_info + 20)
1827         * as a range that we can look at without walking off the
1828         * end of the mapped window.  Its actually the hash size
1829         * that is assured.  An OFS_DELTA longer than the hash size
1830         * is stupid, as then a REF_DELTA would be smaller to store.
1831         */
1832        if (type == OBJ_OFS_DELTA) {
1833                unsigned used = 0;
1834                unsigned char c = base_info[used++];
1835                base_offset = c & 127;
1836                while (c & 128) {
1837                        base_offset += 1;
1838                        if (!base_offset || MSB(base_offset, 7))
1839                                return 0;  /* overflow */
1840                        c = base_info[used++];
1841                        base_offset = (base_offset << 7) + (c & 127);
1842                }
1843                base_offset = delta_obj_offset - base_offset;
1844                if (base_offset <= 0 || base_offset >= delta_obj_offset)
1845                        return 0;  /* out of bound */
1846                *curpos += used;
1847        } else if (type == OBJ_REF_DELTA) {
1848                /* The base entry _must_ be in the same pack */
1849                base_offset = find_pack_entry_one(base_info, p);
1850                *curpos += 20;
1851        } else
1852                die("I am totally screwed");
1853        return base_offset;
1854}
1855
1856/*
1857 * Like get_delta_base above, but we return the sha1 instead of the pack
1858 * offset. This means it is cheaper for REF deltas (we do not have to do
1859 * the final object lookup), but more expensive for OFS deltas (we
1860 * have to load the revidx to convert the offset back into a sha1).
1861 */
1862static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1863                                                struct pack_window **w_curs,
1864                                                off_t curpos,
1865                                                enum object_type type,
1866                                                off_t delta_obj_offset)
1867{
1868        if (type == OBJ_REF_DELTA) {
1869                unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1870                return base;
1871        } else if (type == OBJ_OFS_DELTA) {
1872                struct revindex_entry *revidx;
1873                off_t base_offset = get_delta_base(p, w_curs, &curpos,
1874                                                   type, delta_obj_offset);
1875
1876                if (!base_offset)
1877                        return NULL;
1878
1879                revidx = find_pack_revindex(p, base_offset);
1880                if (!revidx)
1881                        return NULL;
1882
1883                return nth_packed_object_sha1(p, revidx->nr);
1884        } else
1885                return NULL;
1886}
1887
1888int unpack_object_header(struct packed_git *p,
1889                         struct pack_window **w_curs,
1890                         off_t *curpos,
1891                         unsigned long *sizep)
1892{
1893        unsigned char *base;
1894        unsigned long left;
1895        unsigned long used;
1896        enum object_type type;
1897
1898        /* use_pack() assures us we have [base, base + 20) available
1899         * as a range that we can look at.  (Its actually the hash
1900         * size that is assured.)  With our object header encoding
1901         * the maximum deflated object size is 2^137, which is just
1902         * insane, so we know won't exceed what we have been given.
1903         */
1904        base = use_pack(p, w_curs, *curpos, &left);
1905        used = unpack_object_header_buffer(base, left, &type, sizep);
1906        if (!used) {
1907                type = OBJ_BAD;
1908        } else
1909                *curpos += used;
1910
1911        return type;
1912}
1913
1914static int retry_bad_packed_offset(struct packed_git *p, off_t obj_offset)
1915{
1916        int type;
1917        struct revindex_entry *revidx;
1918        const unsigned char *sha1;
1919        revidx = find_pack_revindex(p, obj_offset);
1920        if (!revidx)
1921                return OBJ_BAD;
1922        sha1 = nth_packed_object_sha1(p, revidx->nr);
1923        mark_bad_packed_object(p, sha1);
1924        type = sha1_object_info(sha1, NULL);
1925        if (type <= OBJ_NONE)
1926                return OBJ_BAD;
1927        return type;
1928}
1929
1930#define POI_STACK_PREALLOC 64
1931
1932static enum object_type packed_to_object_type(struct packed_git *p,
1933                                              off_t obj_offset,
1934                                              enum object_type type,
1935                                              struct pack_window **w_curs,
1936                                              off_t curpos)
1937{
1938        off_t small_poi_stack[POI_STACK_PREALLOC];
1939        off_t *poi_stack = small_poi_stack;
1940        int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1941
1942        while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1943                off_t base_offset;
1944                unsigned long size;
1945                /* Push the object we're going to leave behind */
1946                if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1947                        poi_stack_alloc = alloc_nr(poi_stack_nr);
1948                        ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1949                        memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1950                } else {
1951                        ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1952                }
1953                poi_stack[poi_stack_nr++] = obj_offset;
1954                /* If parsing the base offset fails, just unwind */
1955                base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1956                if (!base_offset)
1957                        goto unwind;
1958                curpos = obj_offset = base_offset;
1959                type = unpack_object_header(p, w_curs, &curpos, &size);
1960                if (type <= OBJ_NONE) {
1961                        /* If getting the base itself fails, we first
1962                         * retry the base, otherwise unwind */
1963                        type = retry_bad_packed_offset(p, base_offset);
1964                        if (type > OBJ_NONE)
1965                                goto out;
1966                        goto unwind;
1967                }
1968        }
1969
1970        switch (type) {
1971        case OBJ_BAD:
1972        case OBJ_COMMIT:
1973        case OBJ_TREE:
1974        case OBJ_BLOB:
1975        case OBJ_TAG:
1976                break;
1977        default:
1978                error("unknown object type %i at offset %"PRIuMAX" in %s",
1979                      type, (uintmax_t)obj_offset, p->pack_name);
1980                type = OBJ_BAD;
1981        }
1982
1983out:
1984        if (poi_stack != small_poi_stack)
1985                free(poi_stack);
1986        return type;
1987
1988unwind:
1989        while (poi_stack_nr) {
1990                obj_offset = poi_stack[--poi_stack_nr];
1991                type = retry_bad_packed_offset(p, obj_offset);
1992                if (type > OBJ_NONE)
1993                        goto out;
1994        }
1995        type = OBJ_BAD;
1996        goto out;
1997}
1998
1999static int packed_object_info(struct packed_git *p, off_t obj_offset,
2000                              struct object_info *oi)
2001{
2002        struct pack_window *w_curs = NULL;
2003        unsigned long size;
2004        off_t curpos = obj_offset;
2005        enum object_type type;
2006
2007        /*
2008         * We always get the representation type, but only convert it to
2009         * a "real" type later if the caller is interested.
2010         */
2011        type = unpack_object_header(p, &w_curs, &curpos, &size);
2012
2013        if (oi->sizep) {
2014                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2015                        off_t tmp_pos = curpos;
2016                        off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
2017                                                           type, obj_offset);
2018                        if (!base_offset) {
2019                                type = OBJ_BAD;
2020                                goto out;
2021                        }
2022                        *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
2023                        if (*oi->sizep == 0) {
2024                                type = OBJ_BAD;
2025                                goto out;
2026                        }
2027                } else {
2028                        *oi->sizep = size;
2029                }
2030        }
2031
2032        if (oi->disk_sizep) {
2033                struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2034                *oi->disk_sizep = revidx[1].offset - obj_offset;
2035        }
2036
2037        if (oi->typep) {
2038                *oi->typep = packed_to_object_type(p, obj_offset, type, &w_curs, curpos);
2039                if (*oi->typep < 0) {
2040                        type = OBJ_BAD;
2041                        goto out;
2042                }
2043        }
2044
2045        if (oi->delta_base_sha1) {
2046                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
2047                        const unsigned char *base;
2048
2049                        base = get_delta_base_sha1(p, &w_curs, curpos,
2050                                                   type, obj_offset);
2051                        if (!base) {
2052                                type = OBJ_BAD;
2053                                goto out;
2054                        }
2055
2056                        hashcpy(oi->delta_base_sha1, base);
2057                } else
2058                        hashclr(oi->delta_base_sha1);
2059        }
2060
2061out:
2062        unuse_pack(&w_curs);
2063        return type;
2064}
2065
2066static void *unpack_compressed_entry(struct packed_git *p,
2067                                    struct pack_window **w_curs,
2068                                    off_t curpos,
2069                                    unsigned long size)
2070{
2071        int st;
2072        git_zstream stream;
2073        unsigned char *buffer, *in;
2074
2075        buffer = xmallocz_gently(size);
2076        if (!buffer)
2077                return NULL;
2078        memset(&stream, 0, sizeof(stream));
2079        stream.next_out = buffer;
2080        stream.avail_out = size + 1;
2081
2082        git_inflate_init(&stream);
2083        do {
2084                in = use_pack(p, w_curs, curpos, &stream.avail_in);
2085                stream.next_in = in;
2086                st = git_inflate(&stream, Z_FINISH);
2087                if (!stream.avail_out)
2088                        break; /* the payload is larger than it should be */
2089                curpos += stream.next_in - in;
2090        } while (st == Z_OK || st == Z_BUF_ERROR);
2091        git_inflate_end(&stream);
2092        if ((st != Z_STREAM_END) || stream.total_out != size) {
2093                free(buffer);
2094                return NULL;
2095        }
2096
2097        return buffer;
2098}
2099
2100#define MAX_DELTA_CACHE (256)
2101
2102static size_t delta_base_cached;
2103
2104static struct delta_base_cache_lru_list {
2105        struct delta_base_cache_lru_list *prev;
2106        struct delta_base_cache_lru_list *next;
2107} delta_base_cache_lru = { &delta_base_cache_lru, &delta_base_cache_lru };
2108
2109static struct delta_base_cache_entry {
2110        struct delta_base_cache_lru_list lru;
2111        void *data;
2112        struct packed_git *p;
2113        off_t base_offset;
2114        unsigned long size;
2115        enum object_type type;
2116} delta_base_cache[MAX_DELTA_CACHE];
2117
2118static unsigned long pack_entry_hash(struct packed_git *p, off_t base_offset)
2119{
2120        unsigned long hash;
2121
2122        hash = (unsigned long)(intptr_t)p + (unsigned long)base_offset;
2123        hash += (hash >> 8) + (hash >> 16);
2124        return hash % MAX_DELTA_CACHE;
2125}
2126
2127static struct delta_base_cache_entry *
2128get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
2129{
2130        unsigned long hash = pack_entry_hash(p, base_offset);
2131        return delta_base_cache + hash;
2132}
2133
2134static int eq_delta_base_cache_entry(struct delta_base_cache_entry *ent,
2135                                     struct packed_git *p, off_t base_offset)
2136{
2137        return (ent->data && ent->p == p && ent->base_offset == base_offset);
2138}
2139
2140static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
2141{
2142        struct delta_base_cache_entry *ent;
2143        ent = get_delta_base_cache_entry(p, base_offset);
2144        return eq_delta_base_cache_entry(ent, p, base_offset);
2145}
2146
2147static void clear_delta_base_cache_entry(struct delta_base_cache_entry *ent)
2148{
2149        ent->data = NULL;
2150        ent->lru.next->prev = ent->lru.prev;
2151        ent->lru.prev->next = ent->lru.next;
2152        delta_base_cached -= ent->size;
2153}
2154
2155static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
2156        unsigned long *base_size, enum object_type *type, int keep_cache)
2157{
2158        struct delta_base_cache_entry *ent;
2159        void *ret;
2160
2161        ent = get_delta_base_cache_entry(p, base_offset);
2162
2163        if (!eq_delta_base_cache_entry(ent, p, base_offset))
2164                return unpack_entry(p, base_offset, type, base_size);
2165
2166        ret = ent->data;
2167
2168        if (!keep_cache)
2169                clear_delta_base_cache_entry(ent);
2170        else
2171                ret = xmemdupz(ent->data, ent->size);
2172        *type = ent->type;
2173        *base_size = ent->size;
2174        return ret;
2175}
2176
2177static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
2178{
2179        if (ent->data) {
2180                free(ent->data);
2181                ent->data = NULL;
2182                ent->lru.next->prev = ent->lru.prev;
2183                ent->lru.prev->next = ent->lru.next;
2184                delta_base_cached -= ent->size;
2185        }
2186}
2187
2188void clear_delta_base_cache(void)
2189{
2190        unsigned long p;
2191        for (p = 0; p < MAX_DELTA_CACHE; p++)
2192                release_delta_base_cache(&delta_base_cache[p]);
2193}
2194
2195static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
2196        void *base, unsigned long base_size, enum object_type type)
2197{
2198        unsigned long hash = pack_entry_hash(p, base_offset);
2199        struct delta_base_cache_entry *ent = delta_base_cache + hash;
2200        struct delta_base_cache_lru_list *lru;
2201
2202        release_delta_base_cache(ent);
2203        delta_base_cached += base_size;
2204
2205        for (lru = delta_base_cache_lru.next;
2206             delta_base_cached > delta_base_cache_limit
2207             && lru != &delta_base_cache_lru;
2208             lru = lru->next) {
2209                struct delta_base_cache_entry *f = (void *)lru;
2210                if (f->type == OBJ_BLOB)
2211                        release_delta_base_cache(f);
2212        }
2213        for (lru = delta_base_cache_lru.next;
2214             delta_base_cached > delta_base_cache_limit
2215             && lru != &delta_base_cache_lru;
2216             lru = lru->next) {
2217                struct delta_base_cache_entry *f = (void *)lru;
2218                release_delta_base_cache(f);
2219        }
2220
2221        ent->p = p;
2222        ent->base_offset = base_offset;
2223        ent->type = type;
2224        ent->data = base;
2225        ent->size = base_size;
2226        ent->lru.next = &delta_base_cache_lru;
2227        ent->lru.prev = delta_base_cache_lru.prev;
2228        delta_base_cache_lru.prev->next = &ent->lru;
2229        delta_base_cache_lru.prev = &ent->lru;
2230}
2231
2232static void *read_object(const unsigned char *sha1, enum object_type *type,
2233                         unsigned long *size);
2234
2235static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
2236{
2237        static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
2238        trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
2239                         p->pack_name, (uintmax_t)obj_offset);
2240}
2241
2242int do_check_packed_object_crc;
2243
2244#define UNPACK_ENTRY_STACK_PREALLOC 64
2245struct unpack_entry_stack_ent {
2246        off_t obj_offset;
2247        off_t curpos;
2248        unsigned long size;
2249};
2250
2251void *unpack_entry(struct packed_git *p, off_t obj_offset,
2252                   enum object_type *final_type, unsigned long *final_size)
2253{
2254        struct pack_window *w_curs = NULL;
2255        off_t curpos = obj_offset;
2256        void *data = NULL;
2257        unsigned long size;
2258        enum object_type type;
2259        struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
2260        struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
2261        int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
2262        int base_from_cache = 0;
2263
2264        write_pack_access_log(p, obj_offset);
2265
2266        /* PHASE 1: drill down to the innermost base object */
2267        for (;;) {
2268                off_t base_offset;
2269                int i;
2270                struct delta_base_cache_entry *ent;
2271
2272                ent = get_delta_base_cache_entry(p, curpos);
2273                if (eq_delta_base_cache_entry(ent, p, curpos)) {
2274                        type = ent->type;
2275                        data = ent->data;
2276                        size = ent->size;
2277                        clear_delta_base_cache_entry(ent);
2278                        base_from_cache = 1;
2279                        break;
2280                }
2281
2282                if (do_check_packed_object_crc && p->index_version > 1) {
2283                        struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
2284                        off_t len = revidx[1].offset - obj_offset;
2285                        if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
2286                                const unsigned char *sha1 =
2287                                        nth_packed_object_sha1(p, revidx->nr);
2288                                error("bad packed object CRC for %s",
2289                                      sha1_to_hex(sha1));
2290                                mark_bad_packed_object(p, sha1);
2291                                unuse_pack(&w_curs);
2292                                return NULL;
2293                        }
2294                }
2295
2296                type = unpack_object_header(p, &w_curs, &curpos, &size);
2297                if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
2298                        break;
2299
2300                base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
2301                if (!base_offset) {
2302                        error("failed to validate delta base reference "
2303                              "at offset %"PRIuMAX" from %s",
2304                              (uintmax_t)curpos, p->pack_name);
2305                        /* bail to phase 2, in hopes of recovery */
2306                        data = NULL;
2307                        break;
2308                }
2309
2310                /* push object, proceed to base */
2311                if (delta_stack_nr >= delta_stack_alloc
2312                    && delta_stack == small_delta_stack) {
2313                        delta_stack_alloc = alloc_nr(delta_stack_nr);
2314                        ALLOC_ARRAY(delta_stack, delta_stack_alloc);
2315                        memcpy(delta_stack, small_delta_stack,
2316                               sizeof(*delta_stack)*delta_stack_nr);
2317                } else {
2318                        ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
2319                }
2320                i = delta_stack_nr++;
2321                delta_stack[i].obj_offset = obj_offset;
2322                delta_stack[i].curpos = curpos;
2323                delta_stack[i].size = size;
2324
2325                curpos = obj_offset = base_offset;
2326        }
2327
2328        /* PHASE 2: handle the base */
2329        switch (type) {
2330        case OBJ_OFS_DELTA:
2331        case OBJ_REF_DELTA:
2332                if (data)
2333                        die("BUG in unpack_entry: left loop at a valid delta");
2334                break;
2335        case OBJ_COMMIT:
2336        case OBJ_TREE:
2337        case OBJ_BLOB:
2338        case OBJ_TAG:
2339                if (!base_from_cache)
2340                        data = unpack_compressed_entry(p, &w_curs, curpos, size);
2341                break;
2342        default:
2343                data = NULL;
2344                error("unknown object type %i at offset %"PRIuMAX" in %s",
2345                      type, (uintmax_t)obj_offset, p->pack_name);
2346        }
2347
2348        /* PHASE 3: apply deltas in order */
2349
2350        /* invariants:
2351         *   'data' holds the base data, or NULL if there was corruption
2352         */
2353        while (delta_stack_nr) {
2354                void *delta_data;
2355                void *base = data;
2356                unsigned long delta_size, base_size = size;
2357                int i;
2358
2359                data = NULL;
2360
2361                if (base)
2362                        add_delta_base_cache(p, obj_offset, base, base_size, type);
2363
2364                if (!base) {
2365                        /*
2366                         * We're probably in deep shit, but let's try to fetch
2367                         * the required base anyway from another pack or loose.
2368                         * This is costly but should happen only in the presence
2369                         * of a corrupted pack, and is better than failing outright.
2370                         */
2371                        struct revindex_entry *revidx;
2372                        const unsigned char *base_sha1;
2373                        revidx = find_pack_revindex(p, obj_offset);
2374                        if (revidx) {
2375                                base_sha1 = nth_packed_object_sha1(p, revidx->nr);
2376                                error("failed to read delta base object %s"
2377                                      " at offset %"PRIuMAX" from %s",
2378                                      sha1_to_hex(base_sha1), (uintmax_t)obj_offset,
2379                                      p->pack_name);
2380                                mark_bad_packed_object(p, base_sha1);
2381                                base = read_object(base_sha1, &type, &base_size);
2382                        }
2383                }
2384
2385                i = --delta_stack_nr;
2386                obj_offset = delta_stack[i].obj_offset;
2387                curpos = delta_stack[i].curpos;
2388                delta_size = delta_stack[i].size;
2389
2390                if (!base)
2391                        continue;
2392
2393                delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
2394
2395                if (!delta_data) {
2396                        error("failed to unpack compressed delta "
2397                              "at offset %"PRIuMAX" from %s",
2398                              (uintmax_t)curpos, p->pack_name);
2399                        data = NULL;
2400                        continue;
2401                }
2402
2403                data = patch_delta(base, base_size,
2404                                   delta_data, delta_size,
2405                                   &size);
2406
2407                /*
2408                 * We could not apply the delta; warn the user, but keep going.
2409                 * Our failure will be noticed either in the next iteration of
2410                 * the loop, or if this is the final delta, in the caller when
2411                 * we return NULL. Those code paths will take care of making
2412                 * a more explicit warning and retrying with another copy of
2413                 * the object.
2414                 */
2415                if (!data)
2416                        error("failed to apply delta");
2417
2418                free(delta_data);
2419        }
2420
2421        *final_type = type;
2422        *final_size = size;
2423
2424        unuse_pack(&w_curs);
2425
2426        if (delta_stack != small_delta_stack)
2427                free(delta_stack);
2428
2429        return data;
2430}
2431
2432const unsigned char *nth_packed_object_sha1(struct packed_git *p,
2433                                            uint32_t n)
2434{
2435        const unsigned char *index = p->index_data;
2436        if (!index) {
2437                if (open_pack_index(p))
2438                        return NULL;
2439                index = p->index_data;
2440        }
2441        if (n >= p->num_objects)
2442                return NULL;
2443        index += 4 * 256;
2444        if (p->index_version == 1) {
2445                return index + 24 * n + 4;
2446        } else {
2447                index += 8;
2448                return index + 20 * n;
2449        }
2450}
2451
2452void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
2453{
2454        const unsigned char *ptr = vptr;
2455        const unsigned char *start = p->index_data;
2456        const unsigned char *end = start + p->index_size;
2457        if (ptr < start)
2458                die(_("offset before start of pack index for %s (corrupt index?)"),
2459                    p->pack_name);
2460        /* No need to check for underflow; .idx files must be at least 8 bytes */
2461        if (ptr >= end - 8)
2462                die(_("offset beyond end of pack index for %s (truncated index?)"),
2463                    p->pack_name);
2464}
2465
2466off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
2467{
2468        const unsigned char *index = p->index_data;
2469        index += 4 * 256;
2470        if (p->index_version == 1) {
2471                return ntohl(*((uint32_t *)(index + 24 * n)));
2472        } else {
2473                uint32_t off;
2474                index += 8 + p->num_objects * (20 + 4);
2475                off = ntohl(*((uint32_t *)(index + 4 * n)));
2476                if (!(off & 0x80000000))
2477                        return off;
2478                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
2479                check_pack_index_ptr(p, index);
2480                return (((uint64_t)ntohl(*((uint32_t *)(index + 0)))) << 32) |
2481                                   ntohl(*((uint32_t *)(index + 4)));
2482        }
2483}
2484
2485off_t find_pack_entry_one(const unsigned char *sha1,
2486                                  struct packed_git *p)
2487{
2488        const uint32_t *level1_ofs = p->index_data;
2489        const unsigned char *index = p->index_data;
2490        unsigned hi, lo, stride;
2491        static int use_lookup = -1;
2492        static int debug_lookup = -1;
2493
2494        if (debug_lookup < 0)
2495                debug_lookup = !!getenv("GIT_DEBUG_LOOKUP");
2496
2497        if (!index) {
2498                if (open_pack_index(p))
2499                        return 0;
2500                level1_ofs = p->index_data;
2501                index = p->index_data;
2502        }
2503        if (p->index_version > 1) {
2504                level1_ofs += 2;
2505                index += 8;
2506        }
2507        index += 4 * 256;
2508        hi = ntohl(level1_ofs[*sha1]);
2509        lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
2510        if (p->index_version > 1) {
2511                stride = 20;
2512        } else {
2513                stride = 24;
2514                index += 4;
2515        }
2516
2517        if (debug_lookup)
2518                printf("%02x%02x%02x... lo %u hi %u nr %"PRIu32"\n",
2519                       sha1[0], sha1[1], sha1[2], lo, hi, p->num_objects);
2520
2521        if (use_lookup < 0)
2522                use_lookup = !!getenv("GIT_USE_LOOKUP");
2523        if (use_lookup) {
2524                int pos = sha1_entry_pos(index, stride, 0,
2525                                         lo, hi, p->num_objects, sha1);
2526                if (pos < 0)
2527                        return 0;
2528                return nth_packed_object_offset(p, pos);
2529        }
2530
2531        do {
2532                unsigned mi = (lo + hi) / 2;
2533                int cmp = hashcmp(index + mi * stride, sha1);
2534
2535                if (debug_lookup)
2536                        printf("lo %u hi %u rg %u mi %u\n",
2537                               lo, hi, hi - lo, mi);
2538                if (!cmp)
2539                        return nth_packed_object_offset(p, mi);
2540                if (cmp > 0)
2541                        hi = mi;
2542                else
2543                        lo = mi+1;
2544        } while (lo < hi);
2545        return 0;
2546}
2547
2548int is_pack_valid(struct packed_git *p)
2549{
2550        /* An already open pack is known to be valid. */
2551        if (p->pack_fd != -1)
2552                return 1;
2553
2554        /* If the pack has one window completely covering the
2555         * file size, the pack is known to be valid even if
2556         * the descriptor is not currently open.
2557         */
2558        if (p->windows) {
2559                struct pack_window *w = p->windows;
2560
2561                if (!w->offset && w->len == p->pack_size)
2562                        return 1;
2563        }
2564
2565        /* Force the pack to open to prove its valid. */
2566        return !open_packed_git(p);
2567}
2568
2569static int fill_pack_entry(const unsigned char *sha1,
2570                           struct pack_entry *e,
2571                           struct packed_git *p)
2572{
2573        off_t offset;
2574
2575        if (p->num_bad_objects) {
2576                unsigned i;
2577                for (i = 0; i < p->num_bad_objects; i++)
2578                        if (!hashcmp(sha1, p->bad_object_sha1 + 20 * i))
2579                                return 0;
2580        }
2581
2582        offset = find_pack_entry_one(sha1, p);
2583        if (!offset)
2584                return 0;
2585
2586        /*
2587         * We are about to tell the caller where they can locate the
2588         * requested object.  We better make sure the packfile is
2589         * still here and can be accessed before supplying that
2590         * answer, as it may have been deleted since the index was
2591         * loaded!
2592         */
2593        if (!is_pack_valid(p))
2594                return 0;
2595        e->offset = offset;
2596        e->p = p;
2597        hashcpy(e->sha1, sha1);
2598        return 1;
2599}
2600
2601/*
2602 * Iff a pack file contains the object named by sha1, return true and
2603 * store its location to e.
2604 */
2605static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
2606{
2607        struct packed_git *p;
2608
2609        prepare_packed_git();
2610        if (!packed_git)
2611                return 0;
2612
2613        if (last_found_pack && fill_pack_entry(sha1, e, last_found_pack))
2614                return 1;
2615
2616        for (p = packed_git; p; p = p->next) {
2617                if (p == last_found_pack)
2618                        continue; /* we already checked this one */
2619
2620                if (fill_pack_entry(sha1, e, p)) {
2621                        last_found_pack = p;
2622                        return 1;
2623                }
2624        }
2625        return 0;
2626}
2627
2628struct packed_git *find_sha1_pack(const unsigned char *sha1,
2629                                  struct packed_git *packs)
2630{
2631        struct packed_git *p;
2632
2633        for (p = packs; p; p = p->next) {
2634                if (find_pack_entry_one(sha1, p))
2635                        return p;
2636        }
2637        return NULL;
2638
2639}
2640
2641static int sha1_loose_object_info(const unsigned char *sha1,
2642                                  struct object_info *oi,
2643                                  int flags)
2644{
2645        int status = 0;
2646        unsigned long mapsize;
2647        void *map;
2648        git_zstream stream;
2649        char hdr[32];
2650        struct strbuf hdrbuf = STRBUF_INIT;
2651
2652        if (oi->delta_base_sha1)
2653                hashclr(oi->delta_base_sha1);
2654
2655        /*
2656         * If we don't care about type or size, then we don't
2657         * need to look inside the object at all. Note that we
2658         * do not optimize out the stat call, even if the
2659         * caller doesn't care about the disk-size, since our
2660         * return value implicitly indicates whether the
2661         * object even exists.
2662         */
2663        if (!oi->typep && !oi->typename && !oi->sizep) {
2664                struct stat st;
2665                if (stat_sha1_file(sha1, &st) < 0)
2666                        return -1;
2667                if (oi->disk_sizep)
2668                        *oi->disk_sizep = st.st_size;
2669                return 0;
2670        }
2671
2672        map = map_sha1_file(sha1, &mapsize);
2673        if (!map)
2674                return -1;
2675        if (oi->disk_sizep)
2676                *oi->disk_sizep = mapsize;
2677        if ((flags & LOOKUP_UNKNOWN_OBJECT)) {
2678                if (unpack_sha1_header_to_strbuf(&stream, map, mapsize, hdr, sizeof(hdr), &hdrbuf) < 0)
2679                        status = error("unable to unpack %s header with --allow-unknown-type",
2680                                       sha1_to_hex(sha1));
2681        } else if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
2682                status = error("unable to unpack %s header",
2683                               sha1_to_hex(sha1));
2684        if (status < 0)
2685                ; /* Do nothing */
2686        else if (hdrbuf.len) {
2687                if ((status = parse_sha1_header_extended(hdrbuf.buf, oi, flags)) < 0)
2688                        status = error("unable to parse %s header with --allow-unknown-type",
2689                                       sha1_to_hex(sha1));
2690        } else if ((status = parse_sha1_header_extended(hdr, oi, flags)) < 0)
2691                status = error("unable to parse %s header", sha1_to_hex(sha1));
2692        git_inflate_end(&stream);
2693        munmap(map, mapsize);
2694        if (status && oi->typep)
2695                *oi->typep = status;
2696        strbuf_release(&hdrbuf);
2697        return 0;
2698}
2699
2700int sha1_object_info_extended(const unsigned char *sha1, struct object_info *oi, unsigned flags)
2701{
2702        struct cached_object *co;
2703        struct pack_entry e;
2704        int rtype;
2705        enum object_type real_type;
2706        const unsigned char *real = lookup_replace_object_extended(sha1, flags);
2707
2708        co = find_cached_object(real);
2709        if (co) {
2710                if (oi->typep)
2711                        *(oi->typep) = co->type;
2712                if (oi->sizep)
2713                        *(oi->sizep) = co->size;
2714                if (oi->disk_sizep)
2715                        *(oi->disk_sizep) = 0;
2716                if (oi->delta_base_sha1)
2717                        hashclr(oi->delta_base_sha1);
2718                if (oi->typename)
2719                        strbuf_addstr(oi->typename, typename(co->type));
2720                oi->whence = OI_CACHED;
2721                return 0;
2722        }
2723
2724        if (!find_pack_entry(real, &e)) {
2725                /* Most likely it's a loose object. */
2726                if (!sha1_loose_object_info(real, oi, flags)) {
2727                        oi->whence = OI_LOOSE;
2728                        return 0;
2729                }
2730
2731                /* Not a loose object; someone else may have just packed it. */
2732                reprepare_packed_git();
2733                if (!find_pack_entry(real, &e))
2734                        return -1;
2735        }
2736
2737        /*
2738         * packed_object_info() does not follow the delta chain to
2739         * find out the real type, unless it is given oi->typep.
2740         */
2741        if (oi->typename && !oi->typep)
2742                oi->typep = &real_type;
2743
2744        rtype = packed_object_info(e.p, e.offset, oi);
2745        if (rtype < 0) {
2746                mark_bad_packed_object(e.p, real);
2747                if (oi->typep == &real_type)
2748                        oi->typep = NULL;
2749                return sha1_object_info_extended(real, oi, 0);
2750        } else if (in_delta_base_cache(e.p, e.offset)) {
2751                oi->whence = OI_DBCACHED;
2752        } else {
2753                oi->whence = OI_PACKED;
2754                oi->u.packed.offset = e.offset;
2755                oi->u.packed.pack = e.p;
2756                oi->u.packed.is_delta = (rtype == OBJ_REF_DELTA ||
2757                                         rtype == OBJ_OFS_DELTA);
2758        }
2759        if (oi->typename)
2760                strbuf_addstr(oi->typename, typename(*oi->typep));
2761        if (oi->typep == &real_type)
2762                oi->typep = NULL;
2763
2764        return 0;
2765}
2766
2767/* returns enum object_type or negative */
2768int sha1_object_info(const unsigned char *sha1, unsigned long *sizep)
2769{
2770        enum object_type type;
2771        struct object_info oi = {NULL};
2772
2773        oi.typep = &type;
2774        oi.sizep = sizep;
2775        if (sha1_object_info_extended(sha1, &oi, LOOKUP_REPLACE_OBJECT) < 0)
2776                return -1;
2777        return type;
2778}
2779
2780static void *read_packed_sha1(const unsigned char *sha1,
2781                              enum object_type *type, unsigned long *size)
2782{
2783        struct pack_entry e;
2784        void *data;
2785
2786        if (!find_pack_entry(sha1, &e))
2787                return NULL;
2788        data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
2789        if (!data) {
2790                /*
2791                 * We're probably in deep shit, but let's try to fetch
2792                 * the required object anyway from another pack or loose.
2793                 * This should happen only in the presence of a corrupted
2794                 * pack, and is better than failing outright.
2795                 */
2796                error("failed to read object %s at offset %"PRIuMAX" from %s",
2797                      sha1_to_hex(sha1), (uintmax_t)e.offset, e.p->pack_name);
2798                mark_bad_packed_object(e.p, sha1);
2799                data = read_object(sha1, type, size);
2800        }
2801        return data;
2802}
2803
2804int pretend_sha1_file(void *buf, unsigned long len, enum object_type type,
2805                      unsigned char *sha1)
2806{
2807        struct cached_object *co;
2808
2809        hash_sha1_file(buf, len, typename(type), sha1);
2810        if (has_sha1_file(sha1) || find_cached_object(sha1))
2811                return 0;
2812        ALLOC_GROW(cached_objects, cached_object_nr + 1, cached_object_alloc);
2813        co = &cached_objects[cached_object_nr++];
2814        co->size = len;
2815        co->type = type;
2816        co->buf = xmalloc(len);
2817        memcpy(co->buf, buf, len);
2818        hashcpy(co->sha1, sha1);
2819        return 0;
2820}
2821
2822static void *read_object(const unsigned char *sha1, enum object_type *type,
2823                         unsigned long *size)
2824{
2825        unsigned long mapsize;
2826        void *map, *buf;
2827        struct cached_object *co;
2828
2829        co = find_cached_object(sha1);
2830        if (co) {
2831                *type = co->type;
2832                *size = co->size;
2833                return xmemdupz(co->buf, co->size);
2834        }
2835
2836        buf = read_packed_sha1(sha1, type, size);
2837        if (buf)
2838                return buf;
2839        map = map_sha1_file(sha1, &mapsize);
2840        if (map) {
2841                buf = unpack_sha1_file(map, mapsize, type, size, sha1);
2842                munmap(map, mapsize);
2843                return buf;
2844        }
2845        reprepare_packed_git();
2846        return read_packed_sha1(sha1, type, size);
2847}
2848
2849/*
2850 * This function dies on corrupt objects; the callers who want to
2851 * deal with them should arrange to call read_object() and give error
2852 * messages themselves.
2853 */
2854void *read_sha1_file_extended(const unsigned char *sha1,
2855                              enum object_type *type,
2856                              unsigned long *size,
2857                              unsigned flag)
2858{
2859        void *data;
2860        const struct packed_git *p;
2861        const unsigned char *repl = lookup_replace_object_extended(sha1, flag);
2862
2863        errno = 0;
2864        data = read_object(repl, type, size);
2865        if (data)
2866                return data;
2867
2868        if (errno && errno != ENOENT)
2869                die_errno("failed to read object %s", sha1_to_hex(sha1));
2870
2871        /* die if we replaced an object with one that does not exist */
2872        if (repl != sha1)
2873                die("replacement %s not found for %s",
2874                    sha1_to_hex(repl), sha1_to_hex(sha1));
2875
2876        if (has_loose_object(repl)) {
2877                const char *path = sha1_file_name(sha1);
2878
2879                die("loose object %s (stored in %s) is corrupt",
2880                    sha1_to_hex(repl), path);
2881        }
2882
2883        if ((p = has_packed_and_bad(repl)) != NULL)
2884                die("packed object %s (stored in %s) is corrupt",
2885                    sha1_to_hex(repl), p->pack_name);
2886
2887        return NULL;
2888}
2889
2890void *read_object_with_reference(const unsigned char *sha1,
2891                                 const char *required_type_name,
2892                                 unsigned long *size,
2893                                 unsigned char *actual_sha1_return)
2894{
2895        enum object_type type, required_type;
2896        void *buffer;
2897        unsigned long isize;
2898        unsigned char actual_sha1[20];
2899
2900        required_type = type_from_string(required_type_name);
2901        hashcpy(actual_sha1, sha1);
2902        while (1) {
2903                int ref_length = -1;
2904                const char *ref_type = NULL;
2905
2906                buffer = read_sha1_file(actual_sha1, &type, &isize);
2907                if (!buffer)
2908                        return NULL;
2909                if (type == required_type) {
2910                        *size = isize;
2911                        if (actual_sha1_return)
2912                                hashcpy(actual_sha1_return, actual_sha1);
2913                        return buffer;
2914                }
2915                /* Handle references */
2916                else if (type == OBJ_COMMIT)
2917                        ref_type = "tree ";
2918                else if (type == OBJ_TAG)
2919                        ref_type = "object ";
2920                else {
2921                        free(buffer);
2922                        return NULL;
2923                }
2924                ref_length = strlen(ref_type);
2925
2926                if (ref_length + 40 > isize ||
2927                    memcmp(buffer, ref_type, ref_length) ||
2928                    get_sha1_hex((char *) buffer + ref_length, actual_sha1)) {
2929                        free(buffer);
2930                        return NULL;
2931                }
2932                free(buffer);
2933                /* Now we have the ID of the referred-to object in
2934                 * actual_sha1.  Check again. */
2935        }
2936}
2937
2938static void write_sha1_file_prepare(const void *buf, unsigned long len,
2939                                    const char *type, unsigned char *sha1,
2940                                    char *hdr, int *hdrlen)
2941{
2942        git_SHA_CTX c;
2943
2944        /* Generate the header */
2945        *hdrlen = xsnprintf(hdr, *hdrlen, "%s %lu", type, len)+1;
2946
2947        /* Sha1.. */
2948        git_SHA1_Init(&c);
2949        git_SHA1_Update(&c, hdr, *hdrlen);
2950        git_SHA1_Update(&c, buf, len);
2951        git_SHA1_Final(sha1, &c);
2952}
2953
2954/*
2955 * Move the just written object into its final resting place.
2956 */
2957int finalize_object_file(const char *tmpfile, const char *filename)
2958{
2959        int ret = 0;
2960
2961        if (object_creation_mode == OBJECT_CREATION_USES_RENAMES)
2962                goto try_rename;
2963        else if (link(tmpfile, filename))
2964                ret = errno;
2965
2966        /*
2967         * Coda hack - coda doesn't like cross-directory links,
2968         * so we fall back to a rename, which will mean that it
2969         * won't be able to check collisions, but that's not a
2970         * big deal.
2971         *
2972         * The same holds for FAT formatted media.
2973         *
2974         * When this succeeds, we just return.  We have nothing
2975         * left to unlink.
2976         */
2977        if (ret && ret != EEXIST) {
2978        try_rename:
2979                if (!rename(tmpfile, filename))
2980                        goto out;
2981                ret = errno;
2982        }
2983        unlink_or_warn(tmpfile);
2984        if (ret) {
2985                if (ret != EEXIST) {
2986                        return error_errno("unable to write sha1 filename %s", filename);
2987                }
2988                /* FIXME!!! Collision check here ? */
2989        }
2990
2991out:
2992        if (adjust_shared_perm(filename))
2993                return error("unable to set permission to '%s'", filename);
2994        return 0;
2995}
2996
2997static int write_buffer(int fd, const void *buf, size_t len)
2998{
2999        if (write_in_full(fd, buf, len) < 0)
3000                return error_errno("file write error");
3001        return 0;
3002}
3003
3004int hash_sha1_file(const void *buf, unsigned long len, const char *type,
3005                   unsigned char *sha1)
3006{
3007        char hdr[32];
3008        int hdrlen = sizeof(hdr);
3009        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3010        return 0;
3011}
3012
3013/* Finalize a file on disk, and close it. */
3014static void close_sha1_file(int fd)
3015{
3016        if (fsync_object_files)
3017                fsync_or_die(fd, "sha1 file");
3018        if (close(fd) != 0)
3019                die_errno("error when closing sha1 file");
3020}
3021
3022/* Size of directory component, including the ending '/' */
3023static inline int directory_size(const char *filename)
3024{
3025        const char *s = strrchr(filename, '/');
3026        if (!s)
3027                return 0;
3028        return s - filename + 1;
3029}
3030
3031/*
3032 * This creates a temporary file in the same directory as the final
3033 * 'filename'
3034 *
3035 * We want to avoid cross-directory filename renames, because those
3036 * can have problems on various filesystems (FAT, NFS, Coda).
3037 */
3038static int create_tmpfile(struct strbuf *tmp, const char *filename)
3039{
3040        int fd, dirlen = directory_size(filename);
3041
3042        strbuf_reset(tmp);
3043        strbuf_add(tmp, filename, dirlen);
3044        strbuf_addstr(tmp, "tmp_obj_XXXXXX");
3045        fd = git_mkstemp_mode(tmp->buf, 0444);
3046        if (fd < 0 && dirlen && errno == ENOENT) {
3047                /*
3048                 * Make sure the directory exists; note that the contents
3049                 * of the buffer are undefined after mkstemp returns an
3050                 * error, so we have to rewrite the whole buffer from
3051                 * scratch.
3052                 */
3053                strbuf_reset(tmp);
3054                strbuf_add(tmp, filename, dirlen - 1);
3055                if (mkdir(tmp->buf, 0777) && errno != EEXIST)
3056                        return -1;
3057                if (adjust_shared_perm(tmp->buf))
3058                        return -1;
3059
3060                /* Try again */
3061                strbuf_addstr(tmp, "/tmp_obj_XXXXXX");
3062                fd = git_mkstemp_mode(tmp->buf, 0444);
3063        }
3064        return fd;
3065}
3066
3067static int write_loose_object(const unsigned char *sha1, char *hdr, int hdrlen,
3068                              const void *buf, unsigned long len, time_t mtime)
3069{
3070        int fd, ret;
3071        unsigned char compressed[4096];
3072        git_zstream stream;
3073        git_SHA_CTX c;
3074        unsigned char parano_sha1[20];
3075        static struct strbuf tmp_file = STRBUF_INIT;
3076        const char *filename = sha1_file_name(sha1);
3077
3078        fd = create_tmpfile(&tmp_file, filename);
3079        if (fd < 0) {
3080                if (errno == EACCES)
3081                        return error("insufficient permission for adding an object to repository database %s", get_object_directory());
3082                else
3083                        return error_errno("unable to create temporary file");
3084        }
3085
3086        /* Set it up */
3087        git_deflate_init(&stream, zlib_compression_level);
3088        stream.next_out = compressed;
3089        stream.avail_out = sizeof(compressed);
3090        git_SHA1_Init(&c);
3091
3092        /* First header.. */
3093        stream.next_in = (unsigned char *)hdr;
3094        stream.avail_in = hdrlen;
3095        while (git_deflate(&stream, 0) == Z_OK)
3096                ; /* nothing */
3097        git_SHA1_Update(&c, hdr, hdrlen);
3098
3099        /* Then the data itself.. */
3100        stream.next_in = (void *)buf;
3101        stream.avail_in = len;
3102        do {
3103                unsigned char *in0 = stream.next_in;
3104                ret = git_deflate(&stream, Z_FINISH);
3105                git_SHA1_Update(&c, in0, stream.next_in - in0);
3106                if (write_buffer(fd, compressed, stream.next_out - compressed) < 0)
3107                        die("unable to write sha1 file");
3108                stream.next_out = compressed;
3109                stream.avail_out = sizeof(compressed);
3110        } while (ret == Z_OK);
3111
3112        if (ret != Z_STREAM_END)
3113                die("unable to deflate new object %s (%d)", sha1_to_hex(sha1), ret);
3114        ret = git_deflate_end_gently(&stream);
3115        if (ret != Z_OK)
3116                die("deflateEnd on object %s failed (%d)", sha1_to_hex(sha1), ret);
3117        git_SHA1_Final(parano_sha1, &c);
3118        if (hashcmp(sha1, parano_sha1) != 0)
3119                die("confused by unstable object source data for %s", sha1_to_hex(sha1));
3120
3121        close_sha1_file(fd);
3122
3123        if (mtime) {
3124                struct utimbuf utb;
3125                utb.actime = mtime;
3126                utb.modtime = mtime;
3127                if (utime(tmp_file.buf, &utb) < 0)
3128                        warning_errno("failed utime() on %s", tmp_file.buf);
3129        }
3130
3131        return finalize_object_file(tmp_file.buf, filename);
3132}
3133
3134static int freshen_loose_object(const unsigned char *sha1)
3135{
3136        return check_and_freshen(sha1, 1);
3137}
3138
3139static int freshen_packed_object(const unsigned char *sha1)
3140{
3141        struct pack_entry e;
3142        if (!find_pack_entry(sha1, &e))
3143                return 0;
3144        if (e.p->freshened)
3145                return 1;
3146        if (!freshen_file(e.p->pack_name))
3147                return 0;
3148        e.p->freshened = 1;
3149        return 1;
3150}
3151
3152int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1)
3153{
3154        char hdr[32];
3155        int hdrlen = sizeof(hdr);
3156
3157        /* Normally if we have it in the pack then we do not bother writing
3158         * it out into .git/objects/??/?{38} file.
3159         */
3160        write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
3161        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3162                return 0;
3163        return write_loose_object(sha1, hdr, hdrlen, buf, len, 0);
3164}
3165
3166int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type,
3167                             unsigned char *sha1, unsigned flags)
3168{
3169        char *header;
3170        int hdrlen, status = 0;
3171
3172        /* type string, SP, %lu of the length plus NUL must fit this */
3173        hdrlen = strlen(type) + 32;
3174        header = xmalloc(hdrlen);
3175        write_sha1_file_prepare(buf, len, type, sha1, header, &hdrlen);
3176
3177        if (!(flags & HASH_WRITE_OBJECT))
3178                goto cleanup;
3179        if (freshen_packed_object(sha1) || freshen_loose_object(sha1))
3180                goto cleanup;
3181        status = write_loose_object(sha1, header, hdrlen, buf, len, 0);
3182
3183cleanup:
3184        free(header);
3185        return status;
3186}
3187
3188int force_object_loose(const unsigned char *sha1, time_t mtime)
3189{
3190        void *buf;
3191        unsigned long len;
3192        enum object_type type;
3193        char hdr[32];
3194        int hdrlen;
3195        int ret;
3196
3197        if (has_loose_object(sha1))
3198                return 0;
3199        buf = read_packed_sha1(sha1, &type, &len);
3200        if (!buf)
3201                return error("cannot read sha1_file for %s", sha1_to_hex(sha1));
3202        hdrlen = xsnprintf(hdr, sizeof(hdr), "%s %lu", typename(type), len) + 1;
3203        ret = write_loose_object(sha1, hdr, hdrlen, buf, len, mtime);
3204        free(buf);
3205
3206        return ret;
3207}
3208
3209int has_pack_index(const unsigned char *sha1)
3210{
3211        struct stat st;
3212        if (stat(sha1_pack_index_name(sha1), &st))
3213                return 0;
3214        return 1;
3215}
3216
3217int has_sha1_pack(const unsigned char *sha1)
3218{
3219        struct pack_entry e;
3220        return find_pack_entry(sha1, &e);
3221}
3222
3223int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
3224{
3225        struct pack_entry e;
3226
3227        if (find_pack_entry(sha1, &e))
3228                return 1;
3229        if (has_loose_object(sha1))
3230                return 1;
3231        if (flags & HAS_SHA1_QUICK)
3232                return 0;
3233        reprepare_packed_git();
3234        return find_pack_entry(sha1, &e);
3235}
3236
3237int has_object_file(const struct object_id *oid)
3238{
3239        return has_sha1_file(oid->hash);
3240}
3241
3242static void check_tree(const void *buf, size_t size)
3243{
3244        struct tree_desc desc;
3245        struct name_entry entry;
3246
3247        init_tree_desc(&desc, buf, size);
3248        while (tree_entry(&desc, &entry))
3249                /* do nothing
3250                 * tree_entry() will die() on malformed entries */
3251                ;
3252}
3253
3254static void check_commit(const void *buf, size_t size)
3255{
3256        struct commit c;
3257        memset(&c, 0, sizeof(c));
3258        if (parse_commit_buffer(&c, buf, size))
3259                die("corrupt commit");
3260}
3261
3262static void check_tag(const void *buf, size_t size)
3263{
3264        struct tag t;
3265        memset(&t, 0, sizeof(t));
3266        if (parse_tag_buffer(&t, buf, size))
3267                die("corrupt tag");
3268}
3269
3270static int index_mem(unsigned char *sha1, void *buf, size_t size,
3271                     enum object_type type,
3272                     const char *path, unsigned flags)
3273{
3274        int ret, re_allocated = 0;
3275        int write_object = flags & HASH_WRITE_OBJECT;
3276
3277        if (!type)
3278                type = OBJ_BLOB;
3279
3280        /*
3281         * Convert blobs to git internal format
3282         */
3283        if ((type == OBJ_BLOB) && path) {
3284                struct strbuf nbuf = STRBUF_INIT;
3285                if (convert_to_git(path, buf, size, &nbuf,
3286                                   write_object ? safe_crlf : SAFE_CRLF_FALSE)) {
3287                        buf = strbuf_detach(&nbuf, &size);
3288                        re_allocated = 1;
3289                }
3290        }
3291        if (flags & HASH_FORMAT_CHECK) {
3292                if (type == OBJ_TREE)
3293                        check_tree(buf, size);
3294                if (type == OBJ_COMMIT)
3295                        check_commit(buf, size);
3296                if (type == OBJ_TAG)
3297                        check_tag(buf, size);
3298        }
3299
3300        if (write_object)
3301                ret = write_sha1_file(buf, size, typename(type), sha1);
3302        else
3303                ret = hash_sha1_file(buf, size, typename(type), sha1);
3304        if (re_allocated)
3305                free(buf);
3306        return ret;
3307}
3308
3309static int index_stream_convert_blob(unsigned char *sha1, int fd,
3310                                     const char *path, unsigned flags)
3311{
3312        int ret;
3313        const int write_object = flags & HASH_WRITE_OBJECT;
3314        struct strbuf sbuf = STRBUF_INIT;
3315
3316        assert(path);
3317        assert(would_convert_to_git_filter_fd(path));
3318
3319        convert_to_git_filter_fd(path, fd, &sbuf,
3320                                 write_object ? safe_crlf : SAFE_CRLF_FALSE);
3321
3322        if (write_object)
3323                ret = write_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3324                                      sha1);
3325        else
3326                ret = hash_sha1_file(sbuf.buf, sbuf.len, typename(OBJ_BLOB),
3327                                     sha1);
3328        strbuf_release(&sbuf);
3329        return ret;
3330}
3331
3332static int index_pipe(unsigned char *sha1, int fd, enum object_type type,
3333                      const char *path, unsigned flags)
3334{
3335        struct strbuf sbuf = STRBUF_INIT;
3336        int ret;
3337
3338        if (strbuf_read(&sbuf, fd, 4096) >= 0)
3339                ret = index_mem(sha1, sbuf.buf, sbuf.len, type, path, flags);
3340        else
3341                ret = -1;
3342        strbuf_release(&sbuf);
3343        return ret;
3344}
3345
3346#define SMALL_FILE_SIZE (32*1024)
3347
3348static int index_core(unsigned char *sha1, int fd, size_t size,
3349                      enum object_type type, const char *path,
3350                      unsigned flags)
3351{
3352        int ret;
3353
3354        if (!size) {
3355                ret = index_mem(sha1, "", size, type, path, flags);
3356        } else if (size <= SMALL_FILE_SIZE) {
3357                char *buf = xmalloc(size);
3358                if (size == read_in_full(fd, buf, size))
3359                        ret = index_mem(sha1, buf, size, type, path, flags);
3360                else
3361                        ret = error_errno("short read");
3362                free(buf);
3363        } else {
3364                void *buf = xmmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
3365                ret = index_mem(sha1, buf, size, type, path, flags);
3366                munmap(buf, size);
3367        }
3368        return ret;
3369}
3370
3371/*
3372 * This creates one packfile per large blob unless bulk-checkin
3373 * machinery is "plugged".
3374 *
3375 * This also bypasses the usual "convert-to-git" dance, and that is on
3376 * purpose. We could write a streaming version of the converting
3377 * functions and insert that before feeding the data to fast-import
3378 * (or equivalent in-core API described above). However, that is
3379 * somewhat complicated, as we do not know the size of the filter
3380 * result, which we need to know beforehand when writing a git object.
3381 * Since the primary motivation for trying to stream from the working
3382 * tree file and to avoid mmaping it in core is to deal with large
3383 * binary blobs, they generally do not want to get any conversion, and
3384 * callers should avoid this code path when filters are requested.
3385 */
3386static int index_stream(unsigned char *sha1, int fd, size_t size,
3387                        enum object_type type, const char *path,
3388                        unsigned flags)
3389{
3390        return index_bulk_checkin(sha1, fd, size, type, path, flags);
3391}
3392
3393int index_fd(unsigned char *sha1, int fd, struct stat *st,
3394             enum object_type type, const char *path, unsigned flags)
3395{
3396        int ret;
3397
3398        /*
3399         * Call xsize_t() only when needed to avoid potentially unnecessary
3400         * die() for large files.
3401         */
3402        if (type == OBJ_BLOB && path && would_convert_to_git_filter_fd(path))
3403                ret = index_stream_convert_blob(sha1, fd, path, flags);
3404        else if (!S_ISREG(st->st_mode))
3405                ret = index_pipe(sha1, fd, type, path, flags);
3406        else if (st->st_size <= big_file_threshold || type != OBJ_BLOB ||
3407                 (path && would_convert_to_git(path)))
3408                ret = index_core(sha1, fd, xsize_t(st->st_size), type, path,
3409                                 flags);
3410        else
3411                ret = index_stream(sha1, fd, xsize_t(st->st_size), type, path,
3412                                   flags);
3413        close(fd);
3414        return ret;
3415}
3416
3417int index_path(unsigned char *sha1, const char *path, struct stat *st, unsigned flags)
3418{
3419        int fd;
3420        struct strbuf sb = STRBUF_INIT;
3421
3422        switch (st->st_mode & S_IFMT) {
3423        case S_IFREG:
3424                fd = open(path, O_RDONLY);
3425                if (fd < 0)
3426                        return error_errno("open(\"%s\")", path);
3427                if (index_fd(sha1, fd, st, OBJ_BLOB, path, flags) < 0)
3428                        return error("%s: failed to insert into database",
3429                                     path);
3430                break;
3431        case S_IFLNK:
3432                if (strbuf_readlink(&sb, path, st->st_size))
3433                        return error_errno("readlink(\"%s\")", path);
3434                if (!(flags & HASH_WRITE_OBJECT))
3435                        hash_sha1_file(sb.buf, sb.len, blob_type, sha1);
3436                else if (write_sha1_file(sb.buf, sb.len, blob_type, sha1))
3437                        return error("%s: failed to insert into database",
3438                                     path);
3439                strbuf_release(&sb);
3440                break;
3441        case S_IFDIR:
3442                return resolve_gitlink_ref(path, "HEAD", sha1);
3443        default:
3444                return error("%s: unsupported file type", path);
3445        }
3446        return 0;
3447}
3448
3449int read_pack_header(int fd, struct pack_header *header)
3450{
3451        if (read_in_full(fd, header, sizeof(*header)) < sizeof(*header))
3452                /* "eof before pack header was fully read" */
3453                return PH_ERROR_EOF;
3454
3455        if (header->hdr_signature != htonl(PACK_SIGNATURE))
3456                /* "protocol error (pack signature mismatch detected)" */
3457                return PH_ERROR_PACK_SIGNATURE;
3458        if (!pack_version_ok(header->hdr_version))
3459                /* "protocol error (pack version unsupported)" */
3460                return PH_ERROR_PROTOCOL;
3461        return 0;
3462}
3463
3464void assert_sha1_type(const unsigned char *sha1, enum object_type expect)
3465{
3466        enum object_type type = sha1_object_info(sha1, NULL);
3467        if (type < 0)
3468                die("%s is not a valid object", sha1_to_hex(sha1));
3469        if (type != expect)
3470                die("%s is not a valid '%s' object", sha1_to_hex(sha1),
3471                    typename(expect));
3472}
3473
3474static int for_each_file_in_obj_subdir(int subdir_nr,
3475                                       struct strbuf *path,
3476                                       each_loose_object_fn obj_cb,
3477                                       each_loose_cruft_fn cruft_cb,
3478                                       each_loose_subdir_fn subdir_cb,
3479                                       void *data)
3480{
3481        size_t baselen = path->len;
3482        DIR *dir = opendir(path->buf);
3483        struct dirent *de;
3484        int r = 0;
3485
3486        if (!dir) {
3487                if (errno == ENOENT)
3488                        return 0;
3489                return error_errno("unable to open %s", path->buf);
3490        }
3491
3492        while ((de = readdir(dir))) {
3493                if (is_dot_or_dotdot(de->d_name))
3494                        continue;
3495
3496                strbuf_setlen(path, baselen);
3497                strbuf_addf(path, "/%s", de->d_name);
3498
3499                if (strlen(de->d_name) == 38)  {
3500                        char hex[41];
3501                        unsigned char sha1[20];
3502
3503                        snprintf(hex, sizeof(hex), "%02x%s",
3504                                 subdir_nr, de->d_name);
3505                        if (!get_sha1_hex(hex, sha1)) {
3506                                if (obj_cb) {
3507                                        r = obj_cb(sha1, path->buf, data);
3508                                        if (r)
3509                                                break;
3510                                }
3511                                continue;
3512                        }
3513                }
3514
3515                if (cruft_cb) {
3516                        r = cruft_cb(de->d_name, path->buf, data);
3517                        if (r)
3518                                break;
3519                }
3520        }
3521        closedir(dir);
3522
3523        strbuf_setlen(path, baselen);
3524        if (!r && subdir_cb)
3525                r = subdir_cb(subdir_nr, path->buf, data);
3526
3527        return r;
3528}
3529
3530int for_each_loose_file_in_objdir_buf(struct strbuf *path,
3531                            each_loose_object_fn obj_cb,
3532                            each_loose_cruft_fn cruft_cb,
3533                            each_loose_subdir_fn subdir_cb,
3534                            void *data)
3535{
3536        size_t baselen = path->len;
3537        int r = 0;
3538        int i;
3539
3540        for (i = 0; i < 256; i++) {
3541                strbuf_addf(path, "/%02x", i);
3542                r = for_each_file_in_obj_subdir(i, path, obj_cb, cruft_cb,
3543                                                subdir_cb, data);
3544                strbuf_setlen(path, baselen);
3545                if (r)
3546                        break;
3547        }
3548
3549        return r;
3550}
3551
3552int for_each_loose_file_in_objdir(const char *path,
3553                                  each_loose_object_fn obj_cb,
3554                                  each_loose_cruft_fn cruft_cb,
3555                                  each_loose_subdir_fn subdir_cb,
3556                                  void *data)
3557{
3558        struct strbuf buf = STRBUF_INIT;
3559        int r;
3560
3561        strbuf_addstr(&buf, path);
3562        r = for_each_loose_file_in_objdir_buf(&buf, obj_cb, cruft_cb,
3563                                              subdir_cb, data);
3564        strbuf_release(&buf);
3565
3566        return r;
3567}
3568
3569struct loose_alt_odb_data {
3570        each_loose_object_fn *cb;
3571        void *data;
3572};
3573
3574static int loose_from_alt_odb(struct alternate_object_database *alt,
3575                              void *vdata)
3576{
3577        struct loose_alt_odb_data *data = vdata;
3578        struct strbuf buf = STRBUF_INIT;
3579        int r;
3580
3581        /* copy base not including trailing '/' */
3582        strbuf_add(&buf, alt->base, alt->name - alt->base - 1);
3583        r = for_each_loose_file_in_objdir_buf(&buf,
3584                                              data->cb, NULL, NULL,
3585                                              data->data);
3586        strbuf_release(&buf);
3587        return r;
3588}
3589
3590int for_each_loose_object(each_loose_object_fn cb, void *data, unsigned flags)
3591{
3592        struct loose_alt_odb_data alt;
3593        int r;
3594
3595        r = for_each_loose_file_in_objdir(get_object_directory(),
3596                                          cb, NULL, NULL, data);
3597        if (r)
3598                return r;
3599
3600        if (flags & FOR_EACH_OBJECT_LOCAL_ONLY)
3601                return 0;
3602
3603        alt.cb = cb;
3604        alt.data = data;
3605        return foreach_alt_odb(loose_from_alt_odb, &alt);
3606}
3607
3608static int for_each_object_in_pack(struct packed_git *p, each_packed_object_fn cb, void *data)
3609{
3610        uint32_t i;
3611        int r = 0;
3612
3613        for (i = 0; i < p->num_objects; i++) {
3614                const unsigned char *sha1 = nth_packed_object_sha1(p, i);
3615
3616                if (!sha1)
3617                        return error("unable to get sha1 of object %u in %s",
3618                                     i, p->pack_name);
3619
3620                r = cb(sha1, p, i, data);
3621                if (r)
3622                        break;
3623        }
3624        return r;
3625}
3626
3627int for_each_packed_object(each_packed_object_fn cb, void *data, unsigned flags)
3628{
3629        struct packed_git *p;
3630        int r = 0;
3631        int pack_errors = 0;
3632
3633        prepare_packed_git();
3634        for (p = packed_git; p; p = p->next) {
3635                if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
3636                        continue;
3637                if (open_pack_index(p)) {
3638                        pack_errors = 1;
3639                        continue;
3640                }
3641                r = for_each_object_in_pack(p, cb, data);
3642                if (r)
3643                        break;
3644        }
3645        return r ? r : pack_errors;
3646}