packfile.con commit Merge branch 'jk/trailer-fixes' (fba9654)
   1#include "cache.h"
   2#include "list.h"
   3#include "pack.h"
   4#include "repository.h"
   5#include "dir.h"
   6#include "mergesort.h"
   7#include "packfile.h"
   8#include "delta.h"
   9#include "list.h"
  10#include "streaming.h"
  11#include "sha1-lookup.h"
  12#include "commit.h"
  13#include "object.h"
  14#include "tag.h"
  15#include "tree-walk.h"
  16#include "tree.h"
  17#include "object-store.h"
  18#include "midx.h"
  19
  20char *odb_pack_name(struct strbuf *buf,
  21                    const unsigned char *sha1,
  22                    const char *ext)
  23{
  24        strbuf_reset(buf);
  25        strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  26                    sha1_to_hex(sha1), ext);
  27        return buf->buf;
  28}
  29
  30char *sha1_pack_name(const unsigned char *sha1)
  31{
  32        static struct strbuf buf = STRBUF_INIT;
  33        return odb_pack_name(&buf, sha1, "pack");
  34}
  35
  36char *sha1_pack_index_name(const unsigned char *sha1)
  37{
  38        static struct strbuf buf = STRBUF_INIT;
  39        return odb_pack_name(&buf, sha1, "idx");
  40}
  41
  42static unsigned int pack_used_ctr;
  43static unsigned int pack_mmap_calls;
  44static unsigned int peak_pack_open_windows;
  45static unsigned int pack_open_windows;
  46static unsigned int pack_open_fds;
  47static unsigned int pack_max_fds;
  48static size_t peak_pack_mapped;
  49static size_t pack_mapped;
  50
  51#define SZ_FMT PRIuMAX
  52static inline uintmax_t sz_fmt(size_t s) { return s; }
  53
  54void pack_report(void)
  55{
  56        fprintf(stderr,
  57                "pack_report: getpagesize()            = %10" SZ_FMT "\n"
  58                "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
  59                "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
  60                sz_fmt(getpagesize()),
  61                sz_fmt(packed_git_window_size),
  62                sz_fmt(packed_git_limit));
  63        fprintf(stderr,
  64                "pack_report: pack_used_ctr            = %10u\n"
  65                "pack_report: pack_mmap_calls          = %10u\n"
  66                "pack_report: pack_open_windows        = %10u / %10u\n"
  67                "pack_report: pack_mapped              = "
  68                        "%10" SZ_FMT " / %10" SZ_FMT "\n",
  69                pack_used_ctr,
  70                pack_mmap_calls,
  71                pack_open_windows, peak_pack_open_windows,
  72                sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
  73}
  74
  75/*
  76 * Open and mmap the index file at path, perform a couple of
  77 * consistency checks, then record its information to p.  Return 0 on
  78 * success.
  79 */
  80static int check_packed_git_idx(const char *path, struct packed_git *p)
  81{
  82        void *idx_map;
  83        struct pack_idx_header *hdr;
  84        size_t idx_size;
  85        uint32_t version, nr, i, *index;
  86        int fd = git_open(path);
  87        struct stat st;
  88        const unsigned int hashsz = the_hash_algo->rawsz;
  89
  90        if (fd < 0)
  91                return -1;
  92        if (fstat(fd, &st)) {
  93                close(fd);
  94                return -1;
  95        }
  96        idx_size = xsize_t(st.st_size);
  97        if (idx_size < 4 * 256 + hashsz + hashsz) {
  98                close(fd);
  99                return error("index file %s is too small", path);
 100        }
 101        idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 102        close(fd);
 103
 104        hdr = idx_map;
 105        if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 106                version = ntohl(hdr->idx_version);
 107                if (version < 2 || version > 2) {
 108                        munmap(idx_map, idx_size);
 109                        return error("index file %s is version %"PRIu32
 110                                     " and is not supported by this binary"
 111                                     " (try upgrading GIT to a newer version)",
 112                                     path, version);
 113                }
 114        } else
 115                version = 1;
 116
 117        nr = 0;
 118        index = idx_map;
 119        if (version > 1)
 120                index += 2;  /* skip index header */
 121        for (i = 0; i < 256; i++) {
 122                uint32_t n = ntohl(index[i]);
 123                if (n < nr) {
 124                        munmap(idx_map, idx_size);
 125                        return error("non-monotonic index %s", path);
 126                }
 127                nr = n;
 128        }
 129
 130        if (version == 1) {
 131                /*
 132                 * Total size:
 133                 *  - 256 index entries 4 bytes each
 134                 *  - 24-byte entries * nr (object ID + 4-byte offset)
 135                 *  - hash of the packfile
 136                 *  - file checksum
 137                 */
 138                if (idx_size != 4*256 + nr * (hashsz + 4) + hashsz + hashsz) {
 139                        munmap(idx_map, idx_size);
 140                        return error("wrong index v1 file size in %s", path);
 141                }
 142        } else if (version == 2) {
 143                /*
 144                 * Minimum size:
 145                 *  - 8 bytes of header
 146                 *  - 256 index entries 4 bytes each
 147                 *  - object ID entry * nr
 148                 *  - 4-byte crc entry * nr
 149                 *  - 4-byte offset entry * nr
 150                 *  - hash of the packfile
 151                 *  - file checksum
 152                 * And after the 4-byte offset table might be a
 153                 * variable sized table containing 8-byte entries
 154                 * for offsets larger than 2^31.
 155                 */
 156                unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 157                unsigned long max_size = min_size;
 158                if (nr)
 159                        max_size += (nr - 1)*8;
 160                if (idx_size < min_size || idx_size > max_size) {
 161                        munmap(idx_map, idx_size);
 162                        return error("wrong index v2 file size in %s", path);
 163                }
 164                if (idx_size != min_size &&
 165                    /*
 166                     * make sure we can deal with large pack offsets.
 167                     * 31-bit signed offset won't be enough, neither
 168                     * 32-bit unsigned one will be.
 169                     */
 170                    (sizeof(off_t) <= 4)) {
 171                        munmap(idx_map, idx_size);
 172                        return error("pack too large for current definition of off_t in %s", path);
 173                }
 174        }
 175
 176        p->index_version = version;
 177        p->index_data = idx_map;
 178        p->index_size = idx_size;
 179        p->num_objects = nr;
 180        return 0;
 181}
 182
 183int open_pack_index(struct packed_git *p)
 184{
 185        char *idx_name;
 186        size_t len;
 187        int ret;
 188
 189        if (p->index_data)
 190                return 0;
 191
 192        if (!strip_suffix(p->pack_name, ".pack", &len))
 193                BUG("pack_name does not end in .pack");
 194        idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 195        ret = check_packed_git_idx(idx_name, p);
 196        free(idx_name);
 197        return ret;
 198}
 199
 200uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
 201{
 202        const uint32_t *level1_ofs = p->index_data;
 203
 204        if (!level1_ofs) {
 205                if (open_pack_index(p))
 206                        return 0;
 207                level1_ofs = p->index_data;
 208        }
 209
 210        if (p->index_version > 1) {
 211                level1_ofs += 2;
 212        }
 213
 214        return ntohl(level1_ofs[value]);
 215}
 216
 217static struct packed_git *alloc_packed_git(int extra)
 218{
 219        struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
 220        memset(p, 0, sizeof(*p));
 221        p->pack_fd = -1;
 222        return p;
 223}
 224
 225struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 226{
 227        const char *path = sha1_pack_name(sha1);
 228        size_t alloc = st_add(strlen(path), 1);
 229        struct packed_git *p = alloc_packed_git(alloc);
 230
 231        memcpy(p->pack_name, path, alloc); /* includes NUL */
 232        hashcpy(p->sha1, sha1);
 233        if (check_packed_git_idx(idx_path, p)) {
 234                free(p);
 235                return NULL;
 236        }
 237
 238        return p;
 239}
 240
 241static void scan_windows(struct packed_git *p,
 242        struct packed_git **lru_p,
 243        struct pack_window **lru_w,
 244        struct pack_window **lru_l)
 245{
 246        struct pack_window *w, *w_l;
 247
 248        for (w_l = NULL, w = p->windows; w; w = w->next) {
 249                if (!w->inuse_cnt) {
 250                        if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 251                                *lru_p = p;
 252                                *lru_w = w;
 253                                *lru_l = w_l;
 254                        }
 255                }
 256                w_l = w;
 257        }
 258}
 259
 260static int unuse_one_window(struct packed_git *current)
 261{
 262        struct packed_git *p, *lru_p = NULL;
 263        struct pack_window *lru_w = NULL, *lru_l = NULL;
 264
 265        if (current)
 266                scan_windows(current, &lru_p, &lru_w, &lru_l);
 267        for (p = the_repository->objects->packed_git; p; p = p->next)
 268                scan_windows(p, &lru_p, &lru_w, &lru_l);
 269        if (lru_p) {
 270                munmap(lru_w->base, lru_w->len);
 271                pack_mapped -= lru_w->len;
 272                if (lru_l)
 273                        lru_l->next = lru_w->next;
 274                else
 275                        lru_p->windows = lru_w->next;
 276                free(lru_w);
 277                pack_open_windows--;
 278                return 1;
 279        }
 280        return 0;
 281}
 282
 283void release_pack_memory(size_t need)
 284{
 285        size_t cur = pack_mapped;
 286        while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 287                ; /* nothing */
 288}
 289
 290void close_pack_windows(struct packed_git *p)
 291{
 292        while (p->windows) {
 293                struct pack_window *w = p->windows;
 294
 295                if (w->inuse_cnt)
 296                        die("pack '%s' still has open windows to it",
 297                            p->pack_name);
 298                munmap(w->base, w->len);
 299                pack_mapped -= w->len;
 300                pack_open_windows--;
 301                p->windows = w->next;
 302                free(w);
 303        }
 304}
 305
 306static int close_pack_fd(struct packed_git *p)
 307{
 308        if (p->pack_fd < 0)
 309                return 0;
 310
 311        close(p->pack_fd);
 312        pack_open_fds--;
 313        p->pack_fd = -1;
 314
 315        return 1;
 316}
 317
 318void close_pack_index(struct packed_git *p)
 319{
 320        if (p->index_data) {
 321                munmap((void *)p->index_data, p->index_size);
 322                p->index_data = NULL;
 323        }
 324}
 325
 326void close_pack(struct packed_git *p)
 327{
 328        close_pack_windows(p);
 329        close_pack_fd(p);
 330        close_pack_index(p);
 331}
 332
 333void close_all_packs(struct raw_object_store *o)
 334{
 335        struct packed_git *p;
 336
 337        for (p = o->packed_git; p; p = p->next)
 338                if (p->do_not_close)
 339                        BUG("want to close pack marked 'do-not-close'");
 340                else
 341                        close_pack(p);
 342}
 343
 344/*
 345 * The LRU pack is the one with the oldest MRU window, preferring packs
 346 * with no used windows, or the oldest mtime if it has no windows allocated.
 347 */
 348static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 349{
 350        struct pack_window *w, *this_mru_w;
 351        int has_windows_inuse = 0;
 352
 353        /*
 354         * Reject this pack if it has windows and the previously selected
 355         * one does not.  If this pack does not have windows, reject
 356         * it if the pack file is newer than the previously selected one.
 357         */
 358        if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 359                return;
 360
 361        for (w = this_mru_w = p->windows; w; w = w->next) {
 362                /*
 363                 * Reject this pack if any of its windows are in use,
 364                 * but the previously selected pack did not have any
 365                 * inuse windows.  Otherwise, record that this pack
 366                 * has windows in use.
 367                 */
 368                if (w->inuse_cnt) {
 369                        if (*accept_windows_inuse)
 370                                has_windows_inuse = 1;
 371                        else
 372                                return;
 373                }
 374
 375                if (w->last_used > this_mru_w->last_used)
 376                        this_mru_w = w;
 377
 378                /*
 379                 * Reject this pack if it has windows that have been
 380                 * used more recently than the previously selected pack.
 381                 * If the previously selected pack had windows inuse and
 382                 * we have not encountered a window in this pack that is
 383                 * inuse, skip this check since we prefer a pack with no
 384                 * inuse windows to one that has inuse windows.
 385                 */
 386                if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 387                    this_mru_w->last_used > (*mru_w)->last_used)
 388                        return;
 389        }
 390
 391        /*
 392         * Select this pack.
 393         */
 394        *mru_w = this_mru_w;
 395        *lru_p = p;
 396        *accept_windows_inuse = has_windows_inuse;
 397}
 398
 399static int close_one_pack(void)
 400{
 401        struct packed_git *p, *lru_p = NULL;
 402        struct pack_window *mru_w = NULL;
 403        int accept_windows_inuse = 1;
 404
 405        for (p = the_repository->objects->packed_git; p; p = p->next) {
 406                if (p->pack_fd == -1)
 407                        continue;
 408                find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 409        }
 410
 411        if (lru_p)
 412                return close_pack_fd(lru_p);
 413
 414        return 0;
 415}
 416
 417static unsigned int get_max_fd_limit(void)
 418{
 419#ifdef RLIMIT_NOFILE
 420        {
 421                struct rlimit lim;
 422
 423                if (!getrlimit(RLIMIT_NOFILE, &lim))
 424                        return lim.rlim_cur;
 425        }
 426#endif
 427
 428#ifdef _SC_OPEN_MAX
 429        {
 430                long open_max = sysconf(_SC_OPEN_MAX);
 431                if (0 < open_max)
 432                        return open_max;
 433                /*
 434                 * Otherwise, we got -1 for one of the two
 435                 * reasons:
 436                 *
 437                 * (1) sysconf() did not understand _SC_OPEN_MAX
 438                 *     and signaled an error with -1; or
 439                 * (2) sysconf() said there is no limit.
 440                 *
 441                 * We _could_ clear errno before calling sysconf() to
 442                 * tell these two cases apart and return a huge number
 443                 * in the latter case to let the caller cap it to a
 444                 * value that is not so selfish, but letting the
 445                 * fallback OPEN_MAX codepath take care of these cases
 446                 * is a lot simpler.
 447                 */
 448        }
 449#endif
 450
 451#ifdef OPEN_MAX
 452        return OPEN_MAX;
 453#else
 454        return 1; /* see the caller ;-) */
 455#endif
 456}
 457
 458/*
 459 * Do not call this directly as this leaks p->pack_fd on error return;
 460 * call open_packed_git() instead.
 461 */
 462static int open_packed_git_1(struct packed_git *p)
 463{
 464        struct stat st;
 465        struct pack_header hdr;
 466        unsigned char hash[GIT_MAX_RAWSZ];
 467        unsigned char *idx_hash;
 468        long fd_flag;
 469        ssize_t read_result;
 470        const unsigned hashsz = the_hash_algo->rawsz;
 471
 472        if (!p->index_data) {
 473                struct multi_pack_index *m;
 474                const char *pack_name = strrchr(p->pack_name, '/');
 475
 476                for (m = the_repository->objects->multi_pack_index;
 477                     m; m = m->next) {
 478                        if (midx_contains_pack(m, pack_name))
 479                                break;
 480                }
 481
 482                if (!m && open_pack_index(p))
 483                        return error("packfile %s index unavailable", p->pack_name);
 484        }
 485
 486        if (!pack_max_fds) {
 487                unsigned int max_fds = get_max_fd_limit();
 488
 489                /* Save 3 for stdin/stdout/stderr, 22 for work */
 490                if (25 < max_fds)
 491                        pack_max_fds = max_fds - 25;
 492                else
 493                        pack_max_fds = 1;
 494        }
 495
 496        while (pack_max_fds <= pack_open_fds && close_one_pack())
 497                ; /* nothing */
 498
 499        p->pack_fd = git_open(p->pack_name);
 500        if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 501                return -1;
 502        pack_open_fds++;
 503
 504        /* If we created the struct before we had the pack we lack size. */
 505        if (!p->pack_size) {
 506                if (!S_ISREG(st.st_mode))
 507                        return error("packfile %s not a regular file", p->pack_name);
 508                p->pack_size = st.st_size;
 509        } else if (p->pack_size != st.st_size)
 510                return error("packfile %s size changed", p->pack_name);
 511
 512        /* We leave these file descriptors open with sliding mmap;
 513         * there is no point keeping them open across exec(), though.
 514         */
 515        fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 516        if (fd_flag < 0)
 517                return error("cannot determine file descriptor flags");
 518        fd_flag |= FD_CLOEXEC;
 519        if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 520                return error("cannot set FD_CLOEXEC");
 521
 522        /* Verify we recognize this pack file format. */
 523        read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 524        if (read_result < 0)
 525                return error_errno("error reading from %s", p->pack_name);
 526        if (read_result != sizeof(hdr))
 527                return error("file %s is far too short to be a packfile", p->pack_name);
 528        if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 529                return error("file %s is not a GIT packfile", p->pack_name);
 530        if (!pack_version_ok(hdr.hdr_version))
 531                return error("packfile %s is version %"PRIu32" and not"
 532                        " supported (try upgrading GIT to a newer version)",
 533                        p->pack_name, ntohl(hdr.hdr_version));
 534
 535        /* Skip index checking if in multi-pack-index */
 536        if (!p->index_data)
 537                return 0;
 538
 539        /* Verify the pack matches its index. */
 540        if (p->num_objects != ntohl(hdr.hdr_entries))
 541                return error("packfile %s claims to have %"PRIu32" objects"
 542                             " while index indicates %"PRIu32" objects",
 543                             p->pack_name, ntohl(hdr.hdr_entries),
 544                             p->num_objects);
 545        if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 546                return error("end of packfile %s is unavailable", p->pack_name);
 547        read_result = read_in_full(p->pack_fd, hash, hashsz);
 548        if (read_result < 0)
 549                return error_errno("error reading from %s", p->pack_name);
 550        if (read_result != hashsz)
 551                return error("packfile %s signature is unavailable", p->pack_name);
 552        idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 553        if (hashcmp(hash, idx_hash))
 554                return error("packfile %s does not match index", p->pack_name);
 555        return 0;
 556}
 557
 558static int open_packed_git(struct packed_git *p)
 559{
 560        if (!open_packed_git_1(p))
 561                return 0;
 562        close_pack_fd(p);
 563        return -1;
 564}
 565
 566static int in_window(struct pack_window *win, off_t offset)
 567{
 568        /* We must promise at least one full hash after the
 569         * offset is available from this window, otherwise the offset
 570         * is not actually in this window and a different window (which
 571         * has that one hash excess) must be used.  This is to support
 572         * the object header and delta base parsing routines below.
 573         */
 574        off_t win_off = win->offset;
 575        return win_off <= offset
 576                && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 577}
 578
 579unsigned char *use_pack(struct packed_git *p,
 580                struct pack_window **w_cursor,
 581                off_t offset,
 582                unsigned long *left)
 583{
 584        struct pack_window *win = *w_cursor;
 585
 586        /* Since packfiles end in a hash of their content and it's
 587         * pointless to ask for an offset into the middle of that
 588         * hash, and the in_window function above wouldn't match
 589         * don't allow an offset too close to the end of the file.
 590         */
 591        if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 592                die("packfile %s cannot be accessed", p->pack_name);
 593        if (offset > (p->pack_size - the_hash_algo->rawsz))
 594                die("offset beyond end of packfile (truncated pack?)");
 595        if (offset < 0)
 596                die(_("offset before end of packfile (broken .idx?)"));
 597
 598        if (!win || !in_window(win, offset)) {
 599                if (win)
 600                        win->inuse_cnt--;
 601                for (win = p->windows; win; win = win->next) {
 602                        if (in_window(win, offset))
 603                                break;
 604                }
 605                if (!win) {
 606                        size_t window_align = packed_git_window_size / 2;
 607                        off_t len;
 608
 609                        if (p->pack_fd == -1 && open_packed_git(p))
 610                                die("packfile %s cannot be accessed", p->pack_name);
 611
 612                        win = xcalloc(1, sizeof(*win));
 613                        win->offset = (offset / window_align) * window_align;
 614                        len = p->pack_size - win->offset;
 615                        if (len > packed_git_window_size)
 616                                len = packed_git_window_size;
 617                        win->len = (size_t)len;
 618                        pack_mapped += win->len;
 619                        while (packed_git_limit < pack_mapped
 620                                && unuse_one_window(p))
 621                                ; /* nothing */
 622                        win->base = xmmap(NULL, win->len,
 623                                PROT_READ, MAP_PRIVATE,
 624                                p->pack_fd, win->offset);
 625                        if (win->base == MAP_FAILED)
 626                                die_errno("packfile %s cannot be mapped",
 627                                          p->pack_name);
 628                        if (!win->offset && win->len == p->pack_size
 629                                && !p->do_not_close)
 630                                close_pack_fd(p);
 631                        pack_mmap_calls++;
 632                        pack_open_windows++;
 633                        if (pack_mapped > peak_pack_mapped)
 634                                peak_pack_mapped = pack_mapped;
 635                        if (pack_open_windows > peak_pack_open_windows)
 636                                peak_pack_open_windows = pack_open_windows;
 637                        win->next = p->windows;
 638                        p->windows = win;
 639                }
 640        }
 641        if (win != *w_cursor) {
 642                win->last_used = pack_used_ctr++;
 643                win->inuse_cnt++;
 644                *w_cursor = win;
 645        }
 646        offset -= win->offset;
 647        if (left)
 648                *left = win->len - xsize_t(offset);
 649        return win->base + offset;
 650}
 651
 652void unuse_pack(struct pack_window **w_cursor)
 653{
 654        struct pack_window *w = *w_cursor;
 655        if (w) {
 656                w->inuse_cnt--;
 657                *w_cursor = NULL;
 658        }
 659}
 660
 661static void try_to_free_pack_memory(size_t size)
 662{
 663        release_pack_memory(size);
 664}
 665
 666struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 667{
 668        static int have_set_try_to_free_routine;
 669        struct stat st;
 670        size_t alloc;
 671        struct packed_git *p;
 672
 673        if (!have_set_try_to_free_routine) {
 674                have_set_try_to_free_routine = 1;
 675                set_try_to_free_routine(try_to_free_pack_memory);
 676        }
 677
 678        /*
 679         * Make sure a corresponding .pack file exists and that
 680         * the index looks sane.
 681         */
 682        if (!strip_suffix_mem(path, &path_len, ".idx"))
 683                return NULL;
 684
 685        /*
 686         * ".promisor" is long enough to hold any suffix we're adding (and
 687         * the use xsnprintf double-checks that)
 688         */
 689        alloc = st_add3(path_len, strlen(".promisor"), 1);
 690        p = alloc_packed_git(alloc);
 691        memcpy(p->pack_name, path, path_len);
 692
 693        xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 694        if (!access(p->pack_name, F_OK))
 695                p->pack_keep = 1;
 696
 697        xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 698        if (!access(p->pack_name, F_OK))
 699                p->pack_promisor = 1;
 700
 701        xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 702        if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 703                free(p);
 704                return NULL;
 705        }
 706
 707        /* ok, it looks sane as far as we can check without
 708         * actually mapping the pack file.
 709         */
 710        p->pack_size = st.st_size;
 711        p->pack_local = local;
 712        p->mtime = st.st_mtime;
 713        if (path_len < the_hash_algo->hexsz ||
 714            get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->sha1))
 715                hashclr(p->sha1);
 716        return p;
 717}
 718
 719void install_packed_git(struct repository *r, struct packed_git *pack)
 720{
 721        if (pack->pack_fd != -1)
 722                pack_open_fds++;
 723
 724        pack->next = r->objects->packed_git;
 725        r->objects->packed_git = pack;
 726}
 727
 728void (*report_garbage)(unsigned seen_bits, const char *path);
 729
 730static void report_helper(const struct string_list *list,
 731                          int seen_bits, int first, int last)
 732{
 733        if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 734                return;
 735
 736        for (; first < last; first++)
 737                report_garbage(seen_bits, list->items[first].string);
 738}
 739
 740static void report_pack_garbage(struct string_list *list)
 741{
 742        int i, baselen = -1, first = 0, seen_bits = 0;
 743
 744        if (!report_garbage)
 745                return;
 746
 747        string_list_sort(list);
 748
 749        for (i = 0; i < list->nr; i++) {
 750                const char *path = list->items[i].string;
 751                if (baselen != -1 &&
 752                    strncmp(path, list->items[first].string, baselen)) {
 753                        report_helper(list, seen_bits, first, i);
 754                        baselen = -1;
 755                        seen_bits = 0;
 756                }
 757                if (baselen == -1) {
 758                        const char *dot = strrchr(path, '.');
 759                        if (!dot) {
 760                                report_garbage(PACKDIR_FILE_GARBAGE, path);
 761                                continue;
 762                        }
 763                        baselen = dot - path + 1;
 764                        first = i;
 765                }
 766                if (!strcmp(path + baselen, "pack"))
 767                        seen_bits |= 1;
 768                else if (!strcmp(path + baselen, "idx"))
 769                        seen_bits |= 2;
 770        }
 771        report_helper(list, seen_bits, first, list->nr);
 772}
 773
 774void for_each_file_in_pack_dir(const char *objdir,
 775                               each_file_in_pack_dir_fn fn,
 776                               void *data)
 777{
 778        struct strbuf path = STRBUF_INIT;
 779        size_t dirnamelen;
 780        DIR *dir;
 781        struct dirent *de;
 782
 783        strbuf_addstr(&path, objdir);
 784        strbuf_addstr(&path, "/pack");
 785        dir = opendir(path.buf);
 786        if (!dir) {
 787                if (errno != ENOENT)
 788                        error_errno("unable to open object pack directory: %s",
 789                                    path.buf);
 790                strbuf_release(&path);
 791                return;
 792        }
 793        strbuf_addch(&path, '/');
 794        dirnamelen = path.len;
 795        while ((de = readdir(dir)) != NULL) {
 796                if (is_dot_or_dotdot(de->d_name))
 797                        continue;
 798
 799                strbuf_setlen(&path, dirnamelen);
 800                strbuf_addstr(&path, de->d_name);
 801
 802                fn(path.buf, path.len, de->d_name, data);
 803        }
 804
 805        closedir(dir);
 806        strbuf_release(&path);
 807}
 808
 809struct prepare_pack_data {
 810        struct repository *r;
 811        struct string_list *garbage;
 812        int local;
 813        struct multi_pack_index *m;
 814};
 815
 816static void prepare_pack(const char *full_name, size_t full_name_len,
 817                         const char *file_name, void *_data)
 818{
 819        struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 820        struct packed_git *p;
 821        size_t base_len = full_name_len;
 822
 823        if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 824            !(data->m && midx_contains_pack(data->m, file_name))) {
 825                /* Don't reopen a pack we already have. */
 826                for (p = data->r->objects->packed_git; p; p = p->next) {
 827                        size_t len;
 828                        if (strip_suffix(p->pack_name, ".pack", &len) &&
 829                            len == base_len &&
 830                            !memcmp(p->pack_name, full_name, len))
 831                                break;
 832                }
 833
 834                if (!p) {
 835                        p = add_packed_git(full_name, full_name_len, data->local);
 836                        if (p)
 837                                install_packed_git(data->r, p);
 838                }
 839        }
 840
 841        if (!report_garbage)
 842                return;
 843
 844        if (!strcmp(file_name, "multi-pack-index"))
 845                return;
 846        if (ends_with(file_name, ".idx") ||
 847            ends_with(file_name, ".pack") ||
 848            ends_with(file_name, ".bitmap") ||
 849            ends_with(file_name, ".keep") ||
 850            ends_with(file_name, ".promisor"))
 851                string_list_append(data->garbage, full_name);
 852        else
 853                report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 854}
 855
 856static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 857{
 858        struct prepare_pack_data data;
 859        struct string_list garbage = STRING_LIST_INIT_DUP;
 860
 861        data.m = r->objects->multi_pack_index;
 862
 863        /* look for the multi-pack-index for this object directory */
 864        while (data.m && strcmp(data.m->object_dir, objdir))
 865                data.m = data.m->next;
 866
 867        data.r = r;
 868        data.garbage = &garbage;
 869        data.local = local;
 870
 871        for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 872
 873        report_pack_garbage(data.garbage);
 874        string_list_clear(data.garbage, 0);
 875}
 876
 877static void prepare_packed_git(struct repository *r);
 878/*
 879 * Give a fast, rough count of the number of objects in the repository. This
 880 * ignores loose objects completely. If you have a lot of them, then either
 881 * you should repack because your performance will be awful, or they are
 882 * all unreachable objects about to be pruned, in which case they're not really
 883 * interesting as a measure of repo size in the first place.
 884 */
 885unsigned long approximate_object_count(void)
 886{
 887        if (!the_repository->objects->approximate_object_count_valid) {
 888                unsigned long count;
 889                struct multi_pack_index *m;
 890                struct packed_git *p;
 891
 892                prepare_packed_git(the_repository);
 893                count = 0;
 894                for (m = get_multi_pack_index(the_repository); m; m = m->next)
 895                        count += m->num_objects;
 896                for (p = the_repository->objects->packed_git; p; p = p->next) {
 897                        if (open_pack_index(p))
 898                                continue;
 899                        count += p->num_objects;
 900                }
 901                the_repository->objects->approximate_object_count = count;
 902        }
 903        return the_repository->objects->approximate_object_count;
 904}
 905
 906static void *get_next_packed_git(const void *p)
 907{
 908        return ((const struct packed_git *)p)->next;
 909}
 910
 911static void set_next_packed_git(void *p, void *next)
 912{
 913        ((struct packed_git *)p)->next = next;
 914}
 915
 916static int sort_pack(const void *a_, const void *b_)
 917{
 918        const struct packed_git *a = a_;
 919        const struct packed_git *b = b_;
 920        int st;
 921
 922        /*
 923         * Local packs tend to contain objects specific to our
 924         * variant of the project than remote ones.  In addition,
 925         * remote ones could be on a network mounted filesystem.
 926         * Favor local ones for these reasons.
 927         */
 928        st = a->pack_local - b->pack_local;
 929        if (st)
 930                return -st;
 931
 932        /*
 933         * Younger packs tend to contain more recent objects,
 934         * and more recent objects tend to get accessed more
 935         * often.
 936         */
 937        if (a->mtime < b->mtime)
 938                return 1;
 939        else if (a->mtime == b->mtime)
 940                return 0;
 941        return -1;
 942}
 943
 944static void rearrange_packed_git(struct repository *r)
 945{
 946        r->objects->packed_git = llist_mergesort(
 947                r->objects->packed_git, get_next_packed_git,
 948                set_next_packed_git, sort_pack);
 949}
 950
 951static void prepare_packed_git_mru(struct repository *r)
 952{
 953        struct packed_git *p;
 954
 955        INIT_LIST_HEAD(&r->objects->packed_git_mru);
 956
 957        for (p = r->objects->packed_git; p; p = p->next)
 958                list_add_tail(&p->mru, &r->objects->packed_git_mru);
 959}
 960
 961static void prepare_packed_git(struct repository *r)
 962{
 963        struct alternate_object_database *alt;
 964
 965        if (r->objects->packed_git_initialized)
 966                return;
 967        prepare_multi_pack_index_one(r, r->objects->objectdir, 1);
 968        prepare_packed_git_one(r, r->objects->objectdir, 1);
 969        prepare_alt_odb(r);
 970        for (alt = r->objects->alt_odb_list; alt; alt = alt->next) {
 971                prepare_multi_pack_index_one(r, alt->path, 0);
 972                prepare_packed_git_one(r, alt->path, 0);
 973        }
 974        rearrange_packed_git(r);
 975
 976        r->objects->all_packs = NULL;
 977
 978        prepare_packed_git_mru(r);
 979        r->objects->packed_git_initialized = 1;
 980}
 981
 982void reprepare_packed_git(struct repository *r)
 983{
 984        r->objects->approximate_object_count_valid = 0;
 985        r->objects->packed_git_initialized = 0;
 986        prepare_packed_git(r);
 987}
 988
 989struct packed_git *get_packed_git(struct repository *r)
 990{
 991        prepare_packed_git(r);
 992        return r->objects->packed_git;
 993}
 994
 995struct multi_pack_index *get_multi_pack_index(struct repository *r)
 996{
 997        prepare_packed_git(r);
 998        return r->objects->multi_pack_index;
 999}
1000
1001struct packed_git *get_all_packs(struct repository *r)
1002{
1003        prepare_packed_git(r);
1004
1005        if (!r->objects->all_packs) {
1006                struct packed_git *p = r->objects->packed_git;
1007                struct multi_pack_index *m;
1008
1009                for (m = r->objects->multi_pack_index; m; m = m->next) {
1010                        uint32_t i;
1011                        for (i = 0; i < m->num_packs; i++) {
1012                                if (!prepare_midx_pack(m, i)) {
1013                                        m->packs[i]->next = p;
1014                                        p = m->packs[i];
1015                                }
1016                        }
1017                }
1018
1019                r->objects->all_packs = p;
1020        }
1021
1022        return r->objects->all_packs;
1023}
1024
1025struct list_head *get_packed_git_mru(struct repository *r)
1026{
1027        prepare_packed_git(r);
1028        return &r->objects->packed_git_mru;
1029}
1030
1031unsigned long unpack_object_header_buffer(const unsigned char *buf,
1032                unsigned long len, enum object_type *type, unsigned long *sizep)
1033{
1034        unsigned shift;
1035        unsigned long size, c;
1036        unsigned long used = 0;
1037
1038        c = buf[used++];
1039        *type = (c >> 4) & 7;
1040        size = c & 15;
1041        shift = 4;
1042        while (c & 0x80) {
1043                if (len <= used || bitsizeof(long) <= shift) {
1044                        error("bad object header");
1045                        size = used = 0;
1046                        break;
1047                }
1048                c = buf[used++];
1049                size += (c & 0x7f) << shift;
1050                shift += 7;
1051        }
1052        *sizep = size;
1053        return used;
1054}
1055
1056unsigned long get_size_from_delta(struct packed_git *p,
1057                                  struct pack_window **w_curs,
1058                                  off_t curpos)
1059{
1060        const unsigned char *data;
1061        unsigned char delta_head[20], *in;
1062        git_zstream stream;
1063        int st;
1064
1065        memset(&stream, 0, sizeof(stream));
1066        stream.next_out = delta_head;
1067        stream.avail_out = sizeof(delta_head);
1068
1069        git_inflate_init(&stream);
1070        do {
1071                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1072                stream.next_in = in;
1073                st = git_inflate(&stream, Z_FINISH);
1074                curpos += stream.next_in - in;
1075        } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1076                 stream.total_out < sizeof(delta_head));
1077        git_inflate_end(&stream);
1078        if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1079                error("delta data unpack-initial failed");
1080                return 0;
1081        }
1082
1083        /* Examine the initial part of the delta to figure out
1084         * the result size.
1085         */
1086        data = delta_head;
1087
1088        /* ignore base size */
1089        get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1090
1091        /* Read the result size */
1092        return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1093}
1094
1095int unpack_object_header(struct packed_git *p,
1096                         struct pack_window **w_curs,
1097                         off_t *curpos,
1098                         unsigned long *sizep)
1099{
1100        unsigned char *base;
1101        unsigned long left;
1102        unsigned long used;
1103        enum object_type type;
1104
1105        /* use_pack() assures us we have [base, base + 20) available
1106         * as a range that we can look at.  (Its actually the hash
1107         * size that is assured.)  With our object header encoding
1108         * the maximum deflated object size is 2^137, which is just
1109         * insane, so we know won't exceed what we have been given.
1110         */
1111        base = use_pack(p, w_curs, *curpos, &left);
1112        used = unpack_object_header_buffer(base, left, &type, sizep);
1113        if (!used) {
1114                type = OBJ_BAD;
1115        } else
1116                *curpos += used;
1117
1118        return type;
1119}
1120
1121void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1122{
1123        unsigned i;
1124        for (i = 0; i < p->num_bad_objects; i++)
1125                if (!hashcmp(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1126                        return;
1127        p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1128                                      st_mult(GIT_MAX_RAWSZ,
1129                                              st_add(p->num_bad_objects, 1)));
1130        hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1131        p->num_bad_objects++;
1132}
1133
1134const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1135{
1136        struct packed_git *p;
1137        unsigned i;
1138
1139        for (p = the_repository->objects->packed_git; p; p = p->next)
1140                for (i = 0; i < p->num_bad_objects; i++)
1141                        if (!hashcmp(sha1,
1142                                     p->bad_object_sha1 + the_hash_algo->rawsz * i))
1143                                return p;
1144        return NULL;
1145}
1146
1147static off_t get_delta_base(struct packed_git *p,
1148                                    struct pack_window **w_curs,
1149                                    off_t *curpos,
1150                                    enum object_type type,
1151                                    off_t delta_obj_offset)
1152{
1153        unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1154        off_t base_offset;
1155
1156        /* use_pack() assured us we have [base_info, base_info + 20)
1157         * as a range that we can look at without walking off the
1158         * end of the mapped window.  Its actually the hash size
1159         * that is assured.  An OFS_DELTA longer than the hash size
1160         * is stupid, as then a REF_DELTA would be smaller to store.
1161         */
1162        if (type == OBJ_OFS_DELTA) {
1163                unsigned used = 0;
1164                unsigned char c = base_info[used++];
1165                base_offset = c & 127;
1166                while (c & 128) {
1167                        base_offset += 1;
1168                        if (!base_offset || MSB(base_offset, 7))
1169                                return 0;  /* overflow */
1170                        c = base_info[used++];
1171                        base_offset = (base_offset << 7) + (c & 127);
1172                }
1173                base_offset = delta_obj_offset - base_offset;
1174                if (base_offset <= 0 || base_offset >= delta_obj_offset)
1175                        return 0;  /* out of bound */
1176                *curpos += used;
1177        } else if (type == OBJ_REF_DELTA) {
1178                /* The base entry _must_ be in the same pack */
1179                base_offset = find_pack_entry_one(base_info, p);
1180                *curpos += the_hash_algo->rawsz;
1181        } else
1182                die("I am totally screwed");
1183        return base_offset;
1184}
1185
1186/*
1187 * Like get_delta_base above, but we return the sha1 instead of the pack
1188 * offset. This means it is cheaper for REF deltas (we do not have to do
1189 * the final object lookup), but more expensive for OFS deltas (we
1190 * have to load the revidx to convert the offset back into a sha1).
1191 */
1192static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1193                                                struct pack_window **w_curs,
1194                                                off_t curpos,
1195                                                enum object_type type,
1196                                                off_t delta_obj_offset)
1197{
1198        if (type == OBJ_REF_DELTA) {
1199                unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1200                return base;
1201        } else if (type == OBJ_OFS_DELTA) {
1202                struct revindex_entry *revidx;
1203                off_t base_offset = get_delta_base(p, w_curs, &curpos,
1204                                                   type, delta_obj_offset);
1205
1206                if (!base_offset)
1207                        return NULL;
1208
1209                revidx = find_pack_revindex(p, base_offset);
1210                if (!revidx)
1211                        return NULL;
1212
1213                return nth_packed_object_sha1(p, revidx->nr);
1214        } else
1215                return NULL;
1216}
1217
1218static int retry_bad_packed_offset(struct repository *r,
1219                                   struct packed_git *p,
1220                                   off_t obj_offset)
1221{
1222        int type;
1223        struct revindex_entry *revidx;
1224        struct object_id oid;
1225        revidx = find_pack_revindex(p, obj_offset);
1226        if (!revidx)
1227                return OBJ_BAD;
1228        nth_packed_object_oid(&oid, p, revidx->nr);
1229        mark_bad_packed_object(p, oid.hash);
1230        type = oid_object_info(r, &oid, NULL);
1231        if (type <= OBJ_NONE)
1232                return OBJ_BAD;
1233        return type;
1234}
1235
1236#define POI_STACK_PREALLOC 64
1237
1238static enum object_type packed_to_object_type(struct repository *r,
1239                                              struct packed_git *p,
1240                                              off_t obj_offset,
1241                                              enum object_type type,
1242                                              struct pack_window **w_curs,
1243                                              off_t curpos)
1244{
1245        off_t small_poi_stack[POI_STACK_PREALLOC];
1246        off_t *poi_stack = small_poi_stack;
1247        int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1248
1249        while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1250                off_t base_offset;
1251                unsigned long size;
1252                /* Push the object we're going to leave behind */
1253                if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1254                        poi_stack_alloc = alloc_nr(poi_stack_nr);
1255                        ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1256                        memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1257                } else {
1258                        ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1259                }
1260                poi_stack[poi_stack_nr++] = obj_offset;
1261                /* If parsing the base offset fails, just unwind */
1262                base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1263                if (!base_offset)
1264                        goto unwind;
1265                curpos = obj_offset = base_offset;
1266                type = unpack_object_header(p, w_curs, &curpos, &size);
1267                if (type <= OBJ_NONE) {
1268                        /* If getting the base itself fails, we first
1269                         * retry the base, otherwise unwind */
1270                        type = retry_bad_packed_offset(r, p, base_offset);
1271                        if (type > OBJ_NONE)
1272                                goto out;
1273                        goto unwind;
1274                }
1275        }
1276
1277        switch (type) {
1278        case OBJ_BAD:
1279        case OBJ_COMMIT:
1280        case OBJ_TREE:
1281        case OBJ_BLOB:
1282        case OBJ_TAG:
1283                break;
1284        default:
1285                error("unknown object type %i at offset %"PRIuMAX" in %s",
1286                      type, (uintmax_t)obj_offset, p->pack_name);
1287                type = OBJ_BAD;
1288        }
1289
1290out:
1291        if (poi_stack != small_poi_stack)
1292                free(poi_stack);
1293        return type;
1294
1295unwind:
1296        while (poi_stack_nr) {
1297                obj_offset = poi_stack[--poi_stack_nr];
1298                type = retry_bad_packed_offset(r, p, obj_offset);
1299                if (type > OBJ_NONE)
1300                        goto out;
1301        }
1302        type = OBJ_BAD;
1303        goto out;
1304}
1305
1306static struct hashmap delta_base_cache;
1307static size_t delta_base_cached;
1308
1309static LIST_HEAD(delta_base_cache_lru);
1310
1311struct delta_base_cache_key {
1312        struct packed_git *p;
1313        off_t base_offset;
1314};
1315
1316struct delta_base_cache_entry {
1317        struct hashmap hash;
1318        struct delta_base_cache_key key;
1319        struct list_head lru;
1320        void *data;
1321        unsigned long size;
1322        enum object_type type;
1323};
1324
1325static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1326{
1327        unsigned int hash;
1328
1329        hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1330        hash += (hash >> 8) + (hash >> 16);
1331        return hash;
1332}
1333
1334static struct delta_base_cache_entry *
1335get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1336{
1337        struct hashmap_entry entry;
1338        struct delta_base_cache_key key;
1339
1340        if (!delta_base_cache.cmpfn)
1341                return NULL;
1342
1343        hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1344        key.p = p;
1345        key.base_offset = base_offset;
1346        return hashmap_get(&delta_base_cache, &entry, &key);
1347}
1348
1349static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1350                                   const struct delta_base_cache_key *b)
1351{
1352        return a->p == b->p && a->base_offset == b->base_offset;
1353}
1354
1355static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1356                                     const void *va, const void *vb,
1357                                     const void *vkey)
1358{
1359        const struct delta_base_cache_entry *a = va, *b = vb;
1360        const struct delta_base_cache_key *key = vkey;
1361        if (key)
1362                return !delta_base_cache_key_eq(&a->key, key);
1363        else
1364                return !delta_base_cache_key_eq(&a->key, &b->key);
1365}
1366
1367static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1368{
1369        return !!get_delta_base_cache_entry(p, base_offset);
1370}
1371
1372/*
1373 * Remove the entry from the cache, but do _not_ free the associated
1374 * entry data. The caller takes ownership of the "data" buffer, and
1375 * should copy out any fields it wants before detaching.
1376 */
1377static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1378{
1379        hashmap_remove(&delta_base_cache, ent, &ent->key);
1380        list_del(&ent->lru);
1381        delta_base_cached -= ent->size;
1382        free(ent);
1383}
1384
1385static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1386                                   off_t base_offset, unsigned long *base_size,
1387                                   enum object_type *type)
1388{
1389        struct delta_base_cache_entry *ent;
1390
1391        ent = get_delta_base_cache_entry(p, base_offset);
1392        if (!ent)
1393                return unpack_entry(r, p, base_offset, type, base_size);
1394
1395        if (type)
1396                *type = ent->type;
1397        if (base_size)
1398                *base_size = ent->size;
1399        return xmemdupz(ent->data, ent->size);
1400}
1401
1402static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1403{
1404        free(ent->data);
1405        detach_delta_base_cache_entry(ent);
1406}
1407
1408void clear_delta_base_cache(void)
1409{
1410        struct list_head *lru, *tmp;
1411        list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1412                struct delta_base_cache_entry *entry =
1413                        list_entry(lru, struct delta_base_cache_entry, lru);
1414                release_delta_base_cache(entry);
1415        }
1416}
1417
1418static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1419        void *base, unsigned long base_size, enum object_type type)
1420{
1421        struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1422        struct list_head *lru, *tmp;
1423
1424        delta_base_cached += base_size;
1425
1426        list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1427                struct delta_base_cache_entry *f =
1428                        list_entry(lru, struct delta_base_cache_entry, lru);
1429                if (delta_base_cached <= delta_base_cache_limit)
1430                        break;
1431                release_delta_base_cache(f);
1432        }
1433
1434        ent->key.p = p;
1435        ent->key.base_offset = base_offset;
1436        ent->type = type;
1437        ent->data = base;
1438        ent->size = base_size;
1439        list_add_tail(&ent->lru, &delta_base_cache_lru);
1440
1441        if (!delta_base_cache.cmpfn)
1442                hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1443        hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1444        hashmap_add(&delta_base_cache, ent);
1445}
1446
1447int packed_object_info(struct repository *r, struct packed_git *p,
1448                       off_t obj_offset, struct object_info *oi)
1449{
1450        struct pack_window *w_curs = NULL;
1451        unsigned long size;
1452        off_t curpos = obj_offset;
1453        enum object_type type;
1454
1455        /*
1456         * We always get the representation type, but only convert it to
1457         * a "real" type later if the caller is interested.
1458         */
1459        if (oi->contentp) {
1460                *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1461                                                      &type);
1462                if (!*oi->contentp)
1463                        type = OBJ_BAD;
1464        } else {
1465                type = unpack_object_header(p, &w_curs, &curpos, &size);
1466        }
1467
1468        if (!oi->contentp && oi->sizep) {
1469                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1470                        off_t tmp_pos = curpos;
1471                        off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1472                                                           type, obj_offset);
1473                        if (!base_offset) {
1474                                type = OBJ_BAD;
1475                                goto out;
1476                        }
1477                        *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1478                        if (*oi->sizep == 0) {
1479                                type = OBJ_BAD;
1480                                goto out;
1481                        }
1482                } else {
1483                        *oi->sizep = size;
1484                }
1485        }
1486
1487        if (oi->disk_sizep) {
1488                struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1489                *oi->disk_sizep = revidx[1].offset - obj_offset;
1490        }
1491
1492        if (oi->typep || oi->type_name) {
1493                enum object_type ptot;
1494                ptot = packed_to_object_type(r, p, obj_offset,
1495                                             type, &w_curs, curpos);
1496                if (oi->typep)
1497                        *oi->typep = ptot;
1498                if (oi->type_name) {
1499                        const char *tn = type_name(ptot);
1500                        if (tn)
1501                                strbuf_addstr(oi->type_name, tn);
1502                }
1503                if (ptot < 0) {
1504                        type = OBJ_BAD;
1505                        goto out;
1506                }
1507        }
1508
1509        if (oi->delta_base_sha1) {
1510                if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1511                        const unsigned char *base;
1512
1513                        base = get_delta_base_sha1(p, &w_curs, curpos,
1514                                                   type, obj_offset);
1515                        if (!base) {
1516                                type = OBJ_BAD;
1517                                goto out;
1518                        }
1519
1520                        hashcpy(oi->delta_base_sha1, base);
1521                } else
1522                        hashclr(oi->delta_base_sha1);
1523        }
1524
1525        oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1526                                                          OI_PACKED;
1527
1528out:
1529        unuse_pack(&w_curs);
1530        return type;
1531}
1532
1533static void *unpack_compressed_entry(struct packed_git *p,
1534                                    struct pack_window **w_curs,
1535                                    off_t curpos,
1536                                    unsigned long size)
1537{
1538        int st;
1539        git_zstream stream;
1540        unsigned char *buffer, *in;
1541
1542        buffer = xmallocz_gently(size);
1543        if (!buffer)
1544                return NULL;
1545        memset(&stream, 0, sizeof(stream));
1546        stream.next_out = buffer;
1547        stream.avail_out = size + 1;
1548
1549        git_inflate_init(&stream);
1550        do {
1551                in = use_pack(p, w_curs, curpos, &stream.avail_in);
1552                stream.next_in = in;
1553                st = git_inflate(&stream, Z_FINISH);
1554                if (!stream.avail_out)
1555                        break; /* the payload is larger than it should be */
1556                curpos += stream.next_in - in;
1557        } while (st == Z_OK || st == Z_BUF_ERROR);
1558        git_inflate_end(&stream);
1559        if ((st != Z_STREAM_END) || stream.total_out != size) {
1560                free(buffer);
1561                return NULL;
1562        }
1563
1564        /* versions of zlib can clobber unconsumed portion of outbuf */
1565        buffer[size] = '\0';
1566
1567        return buffer;
1568}
1569
1570static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1571{
1572        static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1573        trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1574                         p->pack_name, (uintmax_t)obj_offset);
1575}
1576
1577int do_check_packed_object_crc;
1578
1579#define UNPACK_ENTRY_STACK_PREALLOC 64
1580struct unpack_entry_stack_ent {
1581        off_t obj_offset;
1582        off_t curpos;
1583        unsigned long size;
1584};
1585
1586static void *read_object(struct repository *r,
1587                         const struct object_id *oid,
1588                         enum object_type *type,
1589                         unsigned long *size)
1590{
1591        struct object_info oi = OBJECT_INFO_INIT;
1592        void *content;
1593        oi.typep = type;
1594        oi.sizep = size;
1595        oi.contentp = &content;
1596
1597        if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1598                return NULL;
1599        return content;
1600}
1601
1602void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1603                   enum object_type *final_type, unsigned long *final_size)
1604{
1605        struct pack_window *w_curs = NULL;
1606        off_t curpos = obj_offset;
1607        void *data = NULL;
1608        unsigned long size;
1609        enum object_type type;
1610        struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1611        struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1612        int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1613        int base_from_cache = 0;
1614
1615        write_pack_access_log(p, obj_offset);
1616
1617        /* PHASE 1: drill down to the innermost base object */
1618        for (;;) {
1619                off_t base_offset;
1620                int i;
1621                struct delta_base_cache_entry *ent;
1622
1623                ent = get_delta_base_cache_entry(p, curpos);
1624                if (ent) {
1625                        type = ent->type;
1626                        data = ent->data;
1627                        size = ent->size;
1628                        detach_delta_base_cache_entry(ent);
1629                        base_from_cache = 1;
1630                        break;
1631                }
1632
1633                if (do_check_packed_object_crc && p->index_version > 1) {
1634                        struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1635                        off_t len = revidx[1].offset - obj_offset;
1636                        if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1637                                struct object_id oid;
1638                                nth_packed_object_oid(&oid, p, revidx->nr);
1639                                error("bad packed object CRC for %s",
1640                                      oid_to_hex(&oid));
1641                                mark_bad_packed_object(p, oid.hash);
1642                                data = NULL;
1643                                goto out;
1644                        }
1645                }
1646
1647                type = unpack_object_header(p, &w_curs, &curpos, &size);
1648                if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1649                        break;
1650
1651                base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1652                if (!base_offset) {
1653                        error("failed to validate delta base reference "
1654                              "at offset %"PRIuMAX" from %s",
1655                              (uintmax_t)curpos, p->pack_name);
1656                        /* bail to phase 2, in hopes of recovery */
1657                        data = NULL;
1658                        break;
1659                }
1660
1661                /* push object, proceed to base */
1662                if (delta_stack_nr >= delta_stack_alloc
1663                    && delta_stack == small_delta_stack) {
1664                        delta_stack_alloc = alloc_nr(delta_stack_nr);
1665                        ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1666                        memcpy(delta_stack, small_delta_stack,
1667                               sizeof(*delta_stack)*delta_stack_nr);
1668                } else {
1669                        ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1670                }
1671                i = delta_stack_nr++;
1672                delta_stack[i].obj_offset = obj_offset;
1673                delta_stack[i].curpos = curpos;
1674                delta_stack[i].size = size;
1675
1676                curpos = obj_offset = base_offset;
1677        }
1678
1679        /* PHASE 2: handle the base */
1680        switch (type) {
1681        case OBJ_OFS_DELTA:
1682        case OBJ_REF_DELTA:
1683                if (data)
1684                        BUG("unpack_entry: left loop at a valid delta");
1685                break;
1686        case OBJ_COMMIT:
1687        case OBJ_TREE:
1688        case OBJ_BLOB:
1689        case OBJ_TAG:
1690                if (!base_from_cache)
1691                        data = unpack_compressed_entry(p, &w_curs, curpos, size);
1692                break;
1693        default:
1694                data = NULL;
1695                error("unknown object type %i at offset %"PRIuMAX" in %s",
1696                      type, (uintmax_t)obj_offset, p->pack_name);
1697        }
1698
1699        /* PHASE 3: apply deltas in order */
1700
1701        /* invariants:
1702         *   'data' holds the base data, or NULL if there was corruption
1703         */
1704        while (delta_stack_nr) {
1705                void *delta_data;
1706                void *base = data;
1707                void *external_base = NULL;
1708                unsigned long delta_size, base_size = size;
1709                int i;
1710
1711                data = NULL;
1712
1713                if (base)
1714                        add_delta_base_cache(p, obj_offset, base, base_size, type);
1715
1716                if (!base) {
1717                        /*
1718                         * We're probably in deep shit, but let's try to fetch
1719                         * the required base anyway from another pack or loose.
1720                         * This is costly but should happen only in the presence
1721                         * of a corrupted pack, and is better than failing outright.
1722                         */
1723                        struct revindex_entry *revidx;
1724                        struct object_id base_oid;
1725                        revidx = find_pack_revindex(p, obj_offset);
1726                        if (revidx) {
1727                                nth_packed_object_oid(&base_oid, p, revidx->nr);
1728                                error("failed to read delta base object %s"
1729                                      " at offset %"PRIuMAX" from %s",
1730                                      oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1731                                      p->pack_name);
1732                                mark_bad_packed_object(p, base_oid.hash);
1733                                base = read_object(r, &base_oid, &type, &base_size);
1734                                external_base = base;
1735                        }
1736                }
1737
1738                i = --delta_stack_nr;
1739                obj_offset = delta_stack[i].obj_offset;
1740                curpos = delta_stack[i].curpos;
1741                delta_size = delta_stack[i].size;
1742
1743                if (!base)
1744                        continue;
1745
1746                delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1747
1748                if (!delta_data) {
1749                        error("failed to unpack compressed delta "
1750                              "at offset %"PRIuMAX" from %s",
1751                              (uintmax_t)curpos, p->pack_name);
1752                        data = NULL;
1753                        free(external_base);
1754                        continue;
1755                }
1756
1757                data = patch_delta(base, base_size,
1758                                   delta_data, delta_size,
1759                                   &size);
1760
1761                /*
1762                 * We could not apply the delta; warn the user, but keep going.
1763                 * Our failure will be noticed either in the next iteration of
1764                 * the loop, or if this is the final delta, in the caller when
1765                 * we return NULL. Those code paths will take care of making
1766                 * a more explicit warning and retrying with another copy of
1767                 * the object.
1768                 */
1769                if (!data)
1770                        error("failed to apply delta");
1771
1772                free(delta_data);
1773                free(external_base);
1774        }
1775
1776        if (final_type)
1777                *final_type = type;
1778        if (final_size)
1779                *final_size = size;
1780
1781out:
1782        unuse_pack(&w_curs);
1783
1784        if (delta_stack != small_delta_stack)
1785                free(delta_stack);
1786
1787        return data;
1788}
1789
1790int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1791{
1792        const unsigned char *index_fanout = p->index_data;
1793        const unsigned char *index_lookup;
1794        const unsigned int hashsz = the_hash_algo->rawsz;
1795        int index_lookup_width;
1796
1797        if (!index_fanout)
1798                BUG("bsearch_pack called without a valid pack-index");
1799
1800        index_lookup = index_fanout + 4 * 256;
1801        if (p->index_version == 1) {
1802                index_lookup_width = hashsz + 4;
1803                index_lookup += 4;
1804        } else {
1805                index_lookup_width = hashsz;
1806                index_fanout += 8;
1807                index_lookup += 8;
1808        }
1809
1810        return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1811                            index_lookup, index_lookup_width, result);
1812}
1813
1814const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1815                                            uint32_t n)
1816{
1817        const unsigned char *index = p->index_data;
1818        const unsigned int hashsz = the_hash_algo->rawsz;
1819        if (!index) {
1820                if (open_pack_index(p))
1821                        return NULL;
1822                index = p->index_data;
1823        }
1824        if (n >= p->num_objects)
1825                return NULL;
1826        index += 4 * 256;
1827        if (p->index_version == 1) {
1828                return index + (hashsz + 4) * n + 4;
1829        } else {
1830                index += 8;
1831                return index + hashsz * n;
1832        }
1833}
1834
1835const struct object_id *nth_packed_object_oid(struct object_id *oid,
1836                                              struct packed_git *p,
1837                                              uint32_t n)
1838{
1839        const unsigned char *hash = nth_packed_object_sha1(p, n);
1840        if (!hash)
1841                return NULL;
1842        hashcpy(oid->hash, hash);
1843        return oid;
1844}
1845
1846void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1847{
1848        const unsigned char *ptr = vptr;
1849        const unsigned char *start = p->index_data;
1850        const unsigned char *end = start + p->index_size;
1851        if (ptr < start)
1852                die(_("offset before start of pack index for %s (corrupt index?)"),
1853                    p->pack_name);
1854        /* No need to check for underflow; .idx files must be at least 8 bytes */
1855        if (ptr >= end - 8)
1856                die(_("offset beyond end of pack index for %s (truncated index?)"),
1857                    p->pack_name);
1858}
1859
1860off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1861{
1862        const unsigned char *index = p->index_data;
1863        const unsigned int hashsz = the_hash_algo->rawsz;
1864        index += 4 * 256;
1865        if (p->index_version == 1) {
1866                return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1867        } else {
1868                uint32_t off;
1869                index += 8 + p->num_objects * (hashsz + 4);
1870                off = ntohl(*((uint32_t *)(index + 4 * n)));
1871                if (!(off & 0x80000000))
1872                        return off;
1873                index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1874                check_pack_index_ptr(p, index);
1875                return get_be64(index);
1876        }
1877}
1878
1879off_t find_pack_entry_one(const unsigned char *sha1,
1880                                  struct packed_git *p)
1881{
1882        const unsigned char *index = p->index_data;
1883        struct object_id oid;
1884        uint32_t result;
1885
1886        if (!index) {
1887                if (open_pack_index(p))
1888                        return 0;
1889        }
1890
1891        hashcpy(oid.hash, sha1);
1892        if (bsearch_pack(&oid, p, &result))
1893                return nth_packed_object_offset(p, result);
1894        return 0;
1895}
1896
1897int is_pack_valid(struct packed_git *p)
1898{
1899        /* An already open pack is known to be valid. */
1900        if (p->pack_fd != -1)
1901                return 1;
1902
1903        /* If the pack has one window completely covering the
1904         * file size, the pack is known to be valid even if
1905         * the descriptor is not currently open.
1906         */
1907        if (p->windows) {
1908                struct pack_window *w = p->windows;
1909
1910                if (!w->offset && w->len == p->pack_size)
1911                        return 1;
1912        }
1913
1914        /* Force the pack to open to prove its valid. */
1915        return !open_packed_git(p);
1916}
1917
1918struct packed_git *find_sha1_pack(const unsigned char *sha1,
1919                                  struct packed_git *packs)
1920{
1921        struct packed_git *p;
1922
1923        for (p = packs; p; p = p->next) {
1924                if (find_pack_entry_one(sha1, p))
1925                        return p;
1926        }
1927        return NULL;
1928
1929}
1930
1931static int fill_pack_entry(const struct object_id *oid,
1932                           struct pack_entry *e,
1933                           struct packed_git *p)
1934{
1935        off_t offset;
1936
1937        if (p->num_bad_objects) {
1938                unsigned i;
1939                for (i = 0; i < p->num_bad_objects; i++)
1940                        if (!hashcmp(oid->hash,
1941                                     p->bad_object_sha1 + the_hash_algo->rawsz * i))
1942                                return 0;
1943        }
1944
1945        offset = find_pack_entry_one(oid->hash, p);
1946        if (!offset)
1947                return 0;
1948
1949        /*
1950         * We are about to tell the caller where they can locate the
1951         * requested object.  We better make sure the packfile is
1952         * still here and can be accessed before supplying that
1953         * answer, as it may have been deleted since the index was
1954         * loaded!
1955         */
1956        if (!is_pack_valid(p))
1957                return 0;
1958        e->offset = offset;
1959        e->p = p;
1960        return 1;
1961}
1962
1963int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1964{
1965        struct list_head *pos;
1966        struct multi_pack_index *m;
1967
1968        prepare_packed_git(r);
1969        if (!r->objects->packed_git && !r->objects->multi_pack_index)
1970                return 0;
1971
1972        for (m = r->objects->multi_pack_index; m; m = m->next) {
1973                if (fill_midx_entry(oid, e, m))
1974                        return 1;
1975        }
1976
1977        list_for_each(pos, &r->objects->packed_git_mru) {
1978                struct packed_git *p = list_entry(pos, struct packed_git, mru);
1979                if (fill_pack_entry(oid, e, p)) {
1980                        list_move(&p->mru, &r->objects->packed_git_mru);
1981                        return 1;
1982                }
1983        }
1984        return 0;
1985}
1986
1987int has_object_pack(const struct object_id *oid)
1988{
1989        struct pack_entry e;
1990        return find_pack_entry(the_repository, oid, &e);
1991}
1992
1993int has_pack_index(const unsigned char *sha1)
1994{
1995        struct stat st;
1996        if (stat(sha1_pack_index_name(sha1), &st))
1997                return 0;
1998        return 1;
1999}
2000
2001int for_each_object_in_pack(struct packed_git *p,
2002                            each_packed_object_fn cb, void *data,
2003                            enum for_each_object_flags flags)
2004{
2005        uint32_t i;
2006        int r = 0;
2007
2008        if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2009                load_pack_revindex(p);
2010
2011        for (i = 0; i < p->num_objects; i++) {
2012                uint32_t pos;
2013                struct object_id oid;
2014
2015                if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2016                        pos = p->revindex[i].nr;
2017                else
2018                        pos = i;
2019
2020                if (!nth_packed_object_oid(&oid, p, pos))
2021                        return error("unable to get sha1 of object %u in %s",
2022                                     pos, p->pack_name);
2023
2024                r = cb(&oid, p, pos, data);
2025                if (r)
2026                        break;
2027        }
2028        return r;
2029}
2030
2031int for_each_packed_object(each_packed_object_fn cb, void *data,
2032                           enum for_each_object_flags flags)
2033{
2034        struct packed_git *p;
2035        int r = 0;
2036        int pack_errors = 0;
2037
2038        prepare_packed_git(the_repository);
2039        for (p = get_all_packs(the_repository); p; p = p->next) {
2040                if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2041                        continue;
2042                if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2043                    !p->pack_promisor)
2044                        continue;
2045                if (open_pack_index(p)) {
2046                        pack_errors = 1;
2047                        continue;
2048                }
2049                r = for_each_object_in_pack(p, cb, data, flags);
2050                if (r)
2051                        break;
2052        }
2053        return r ? r : pack_errors;
2054}
2055
2056static int add_promisor_object(const struct object_id *oid,
2057                               struct packed_git *pack,
2058                               uint32_t pos,
2059                               void *set_)
2060{
2061        struct oidset *set = set_;
2062        struct object *obj = parse_object(the_repository, oid);
2063        if (!obj)
2064                return 1;
2065
2066        oidset_insert(set, oid);
2067
2068        /*
2069         * If this is a tree, commit, or tag, the objects it refers
2070         * to are also promisor objects. (Blobs refer to no objects->)
2071         */
2072        if (obj->type == OBJ_TREE) {
2073                struct tree *tree = (struct tree *)obj;
2074                struct tree_desc desc;
2075                struct name_entry entry;
2076                if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2077                        /*
2078                         * Error messages are given when packs are
2079                         * verified, so do not print any here.
2080                         */
2081                        return 0;
2082                while (tree_entry_gently(&desc, &entry))
2083                        oidset_insert(set, entry.oid);
2084        } else if (obj->type == OBJ_COMMIT) {
2085                struct commit *commit = (struct commit *) obj;
2086                struct commit_list *parents = commit->parents;
2087
2088                oidset_insert(set, get_commit_tree_oid(commit));
2089                for (; parents; parents = parents->next)
2090                        oidset_insert(set, &parents->item->object.oid);
2091        } else if (obj->type == OBJ_TAG) {
2092                struct tag *tag = (struct tag *) obj;
2093                oidset_insert(set, &tag->tagged->oid);
2094        }
2095        return 0;
2096}
2097
2098int is_promisor_object(const struct object_id *oid)
2099{
2100        static struct oidset promisor_objects;
2101        static int promisor_objects_prepared;
2102
2103        if (!promisor_objects_prepared) {
2104                if (repository_format_partial_clone) {
2105                        for_each_packed_object(add_promisor_object,
2106                                               &promisor_objects,
2107                                               FOR_EACH_OBJECT_PROMISOR_ONLY);
2108                }
2109                promisor_objects_prepared = 1;
2110        }
2111        return oidset_contains(&promisor_objects, oid);
2112}