read-cache.con commit Merge branch 'jk/close-duped-fd-before-unlock-for-bundle' (9e3dc6b)
   1/*
   2 * GIT - The information manager from hell
   3 *
   4 * Copyright (C) Linus Torvalds, 2005
   5 */
   6#define NO_THE_INDEX_COMPATIBILITY_MACROS
   7#include "cache.h"
   8#include "config.h"
   9#include "diff.h"
  10#include "diffcore.h"
  11#include "tempfile.h"
  12#include "lockfile.h"
  13#include "cache-tree.h"
  14#include "refs.h"
  15#include "dir.h"
  16#include "object-store.h"
  17#include "tree.h"
  18#include "commit.h"
  19#include "blob.h"
  20#include "resolve-undo.h"
  21#include "strbuf.h"
  22#include "varint.h"
  23#include "split-index.h"
  24#include "utf8.h"
  25#include "fsmonitor.h"
  26#include "thread-utils.h"
  27#include "progress.h"
  28
  29/* Mask for the name length in ce_flags in the on-disk index */
  30
  31#define CE_NAMEMASK  (0x0fff)
  32
  33/* Index extensions.
  34 *
  35 * The first letter should be 'A'..'Z' for extensions that are not
  36 * necessary for a correct operation (i.e. optimization data).
  37 * When new extensions are added that _needs_ to be understood in
  38 * order to correctly interpret the index file, pick character that
  39 * is outside the range, to cause the reader to abort.
  40 */
  41
  42#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  43#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  44#define CACHE_EXT_RESOLVE_UNDO 0x52455543 /* "REUC" */
  45#define CACHE_EXT_LINK 0x6c696e6b         /* "link" */
  46#define CACHE_EXT_UNTRACKED 0x554E5452    /* "UNTR" */
  47#define CACHE_EXT_FSMONITOR 0x46534D4E    /* "FSMN" */
  48#define CACHE_EXT_ENDOFINDEXENTRIES 0x454F4945  /* "EOIE" */
  49#define CACHE_EXT_INDEXENTRYOFFSETTABLE 0x49454F54 /* "IEOT" */
  50
  51/* changes that can be kept in $GIT_DIR/index (basically all extensions) */
  52#define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \
  53                 CE_ENTRY_ADDED | CE_ENTRY_REMOVED | CE_ENTRY_CHANGED | \
  54                 SPLIT_INDEX_ORDERED | UNTRACKED_CHANGED | FSMONITOR_CHANGED)
  55
  56
  57/*
  58 * This is an estimate of the pathname length in the index.  We use
  59 * this for V4 index files to guess the un-deltafied size of the index
  60 * in memory because of pathname deltafication.  This is not required
  61 * for V2/V3 index formats because their pathnames are not compressed.
  62 * If the initial amount of memory set aside is not sufficient, the
  63 * mem pool will allocate extra memory.
  64 */
  65#define CACHE_ENTRY_PATH_LENGTH 80
  66
  67static inline struct cache_entry *mem_pool__ce_alloc(struct mem_pool *mem_pool, size_t len)
  68{
  69        struct cache_entry *ce;
  70        ce = mem_pool_alloc(mem_pool, cache_entry_size(len));
  71        ce->mem_pool_allocated = 1;
  72        return ce;
  73}
  74
  75static inline struct cache_entry *mem_pool__ce_calloc(struct mem_pool *mem_pool, size_t len)
  76{
  77        struct cache_entry * ce;
  78        ce = mem_pool_calloc(mem_pool, 1, cache_entry_size(len));
  79        ce->mem_pool_allocated = 1;
  80        return ce;
  81}
  82
  83static struct mem_pool *find_mem_pool(struct index_state *istate)
  84{
  85        struct mem_pool **pool_ptr;
  86
  87        if (istate->split_index && istate->split_index->base)
  88                pool_ptr = &istate->split_index->base->ce_mem_pool;
  89        else
  90                pool_ptr = &istate->ce_mem_pool;
  91
  92        if (!*pool_ptr)
  93                mem_pool_init(pool_ptr, 0);
  94
  95        return *pool_ptr;
  96}
  97
  98struct index_state the_index;
  99static const char *alternate_index_output;
 100
 101static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
 102{
 103        istate->cache[nr] = ce;
 104        add_name_hash(istate, ce);
 105}
 106
 107static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
 108{
 109        struct cache_entry *old = istate->cache[nr];
 110
 111        replace_index_entry_in_base(istate, old, ce);
 112        remove_name_hash(istate, old);
 113        discard_cache_entry(old);
 114        ce->ce_flags &= ~CE_HASHED;
 115        set_index_entry(istate, nr, ce);
 116        ce->ce_flags |= CE_UPDATE_IN_BASE;
 117        mark_fsmonitor_invalid(istate, ce);
 118        istate->cache_changed |= CE_ENTRY_CHANGED;
 119}
 120
 121void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
 122{
 123        struct cache_entry *old_entry = istate->cache[nr], *new_entry;
 124        int namelen = strlen(new_name);
 125
 126        new_entry = make_empty_cache_entry(istate, namelen);
 127        copy_cache_entry(new_entry, old_entry);
 128        new_entry->ce_flags &= ~CE_HASHED;
 129        new_entry->ce_namelen = namelen;
 130        new_entry->index = 0;
 131        memcpy(new_entry->name, new_name, namelen + 1);
 132
 133        cache_tree_invalidate_path(istate, old_entry->name);
 134        untracked_cache_remove_from_index(istate, old_entry->name);
 135        remove_index_entry_at(istate, nr);
 136        add_index_entry(istate, new_entry, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
 137}
 138
 139void fill_stat_data(struct stat_data *sd, struct stat *st)
 140{
 141        sd->sd_ctime.sec = (unsigned int)st->st_ctime;
 142        sd->sd_mtime.sec = (unsigned int)st->st_mtime;
 143        sd->sd_ctime.nsec = ST_CTIME_NSEC(*st);
 144        sd->sd_mtime.nsec = ST_MTIME_NSEC(*st);
 145        sd->sd_dev = st->st_dev;
 146        sd->sd_ino = st->st_ino;
 147        sd->sd_uid = st->st_uid;
 148        sd->sd_gid = st->st_gid;
 149        sd->sd_size = st->st_size;
 150}
 151
 152int match_stat_data(const struct stat_data *sd, struct stat *st)
 153{
 154        int changed = 0;
 155
 156        if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
 157                changed |= MTIME_CHANGED;
 158        if (trust_ctime && check_stat &&
 159            sd->sd_ctime.sec != (unsigned int)st->st_ctime)
 160                changed |= CTIME_CHANGED;
 161
 162#ifdef USE_NSEC
 163        if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
 164                changed |= MTIME_CHANGED;
 165        if (trust_ctime && check_stat &&
 166            sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
 167                changed |= CTIME_CHANGED;
 168#endif
 169
 170        if (check_stat) {
 171                if (sd->sd_uid != (unsigned int) st->st_uid ||
 172                        sd->sd_gid != (unsigned int) st->st_gid)
 173                        changed |= OWNER_CHANGED;
 174                if (sd->sd_ino != (unsigned int) st->st_ino)
 175                        changed |= INODE_CHANGED;
 176        }
 177
 178#ifdef USE_STDEV
 179        /*
 180         * st_dev breaks on network filesystems where different
 181         * clients will have different views of what "device"
 182         * the filesystem is on
 183         */
 184        if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
 185                        changed |= INODE_CHANGED;
 186#endif
 187
 188        if (sd->sd_size != (unsigned int) st->st_size)
 189                changed |= DATA_CHANGED;
 190
 191        return changed;
 192}
 193
 194/*
 195 * This only updates the "non-critical" parts of the directory
 196 * cache, ie the parts that aren't tracked by GIT, and only used
 197 * to validate the cache.
 198 */
 199void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 200{
 201        fill_stat_data(&ce->ce_stat_data, st);
 202
 203        if (assume_unchanged)
 204                ce->ce_flags |= CE_VALID;
 205
 206        if (S_ISREG(st->st_mode)) {
 207                ce_mark_uptodate(ce);
 208                mark_fsmonitor_valid(ce);
 209        }
 210}
 211
 212static int ce_compare_data(struct index_state *istate,
 213                           const struct cache_entry *ce,
 214                           struct stat *st)
 215{
 216        int match = -1;
 217        int fd = git_open_cloexec(ce->name, O_RDONLY);
 218
 219        if (fd >= 0) {
 220                struct object_id oid;
 221                if (!index_fd(istate, &oid, fd, st, OBJ_BLOB, ce->name, 0))
 222                        match = !oideq(&oid, &ce->oid);
 223                /* index_fd() closed the file descriptor already */
 224        }
 225        return match;
 226}
 227
 228static int ce_compare_link(const struct cache_entry *ce, size_t expected_size)
 229{
 230        int match = -1;
 231        void *buffer;
 232        unsigned long size;
 233        enum object_type type;
 234        struct strbuf sb = STRBUF_INIT;
 235
 236        if (strbuf_readlink(&sb, ce->name, expected_size))
 237                return -1;
 238
 239        buffer = read_object_file(&ce->oid, &type, &size);
 240        if (buffer) {
 241                if (size == sb.len)
 242                        match = memcmp(buffer, sb.buf, size);
 243                free(buffer);
 244        }
 245        strbuf_release(&sb);
 246        return match;
 247}
 248
 249static int ce_compare_gitlink(const struct cache_entry *ce)
 250{
 251        struct object_id oid;
 252
 253        /*
 254         * We don't actually require that the .git directory
 255         * under GITLINK directory be a valid git directory. It
 256         * might even be missing (in case nobody populated that
 257         * sub-project).
 258         *
 259         * If so, we consider it always to match.
 260         */
 261        if (resolve_gitlink_ref(ce->name, "HEAD", &oid) < 0)
 262                return 0;
 263        return !oideq(&oid, &ce->oid);
 264}
 265
 266static int ce_modified_check_fs(struct index_state *istate,
 267                                const struct cache_entry *ce,
 268                                struct stat *st)
 269{
 270        switch (st->st_mode & S_IFMT) {
 271        case S_IFREG:
 272                if (ce_compare_data(istate, ce, st))
 273                        return DATA_CHANGED;
 274                break;
 275        case S_IFLNK:
 276                if (ce_compare_link(ce, xsize_t(st->st_size)))
 277                        return DATA_CHANGED;
 278                break;
 279        case S_IFDIR:
 280                if (S_ISGITLINK(ce->ce_mode))
 281                        return ce_compare_gitlink(ce) ? DATA_CHANGED : 0;
 282                /* else fallthrough */
 283        default:
 284                return TYPE_CHANGED;
 285        }
 286        return 0;
 287}
 288
 289static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 290{
 291        unsigned int changed = 0;
 292
 293        if (ce->ce_flags & CE_REMOVE)
 294                return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 295
 296        switch (ce->ce_mode & S_IFMT) {
 297        case S_IFREG:
 298                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 299                /* We consider only the owner x bit to be relevant for
 300                 * "mode changes"
 301                 */
 302                if (trust_executable_bit &&
 303                    (0100 & (ce->ce_mode ^ st->st_mode)))
 304                        changed |= MODE_CHANGED;
 305                break;
 306        case S_IFLNK:
 307                if (!S_ISLNK(st->st_mode) &&
 308                    (has_symlinks || !S_ISREG(st->st_mode)))
 309                        changed |= TYPE_CHANGED;
 310                break;
 311        case S_IFGITLINK:
 312                /* We ignore most of the st_xxx fields for gitlinks */
 313                if (!S_ISDIR(st->st_mode))
 314                        changed |= TYPE_CHANGED;
 315                else if (ce_compare_gitlink(ce))
 316                        changed |= DATA_CHANGED;
 317                return changed;
 318        default:
 319                die("internal error: ce_mode is %o", ce->ce_mode);
 320        }
 321
 322        changed |= match_stat_data(&ce->ce_stat_data, st);
 323
 324        /* Racily smudged entry? */
 325        if (!ce->ce_stat_data.sd_size) {
 326                if (!is_empty_blob_sha1(ce->oid.hash))
 327                        changed |= DATA_CHANGED;
 328        }
 329
 330        return changed;
 331}
 332
 333static int is_racy_stat(const struct index_state *istate,
 334                        const struct stat_data *sd)
 335{
 336        return (istate->timestamp.sec &&
 337#ifdef USE_NSEC
 338                 /* nanosecond timestamped files can also be racy! */
 339                (istate->timestamp.sec < sd->sd_mtime.sec ||
 340                 (istate->timestamp.sec == sd->sd_mtime.sec &&
 341                  istate->timestamp.nsec <= sd->sd_mtime.nsec))
 342#else
 343                istate->timestamp.sec <= sd->sd_mtime.sec
 344#endif
 345                );
 346}
 347
 348int is_racy_timestamp(const struct index_state *istate,
 349                             const struct cache_entry *ce)
 350{
 351        return (!S_ISGITLINK(ce->ce_mode) &&
 352                is_racy_stat(istate, &ce->ce_stat_data));
 353}
 354
 355int match_stat_data_racy(const struct index_state *istate,
 356                         const struct stat_data *sd, struct stat *st)
 357{
 358        if (is_racy_stat(istate, sd))
 359                return MTIME_CHANGED;
 360        return match_stat_data(sd, st);
 361}
 362
 363int ie_match_stat(struct index_state *istate,
 364                  const struct cache_entry *ce, struct stat *st,
 365                  unsigned int options)
 366{
 367        unsigned int changed;
 368        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 369        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
 370        int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 371        int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR;
 372
 373        if (!ignore_fsmonitor)
 374                refresh_fsmonitor(istate);
 375        /*
 376         * If it's marked as always valid in the index, it's
 377         * valid whatever the checked-out copy says.
 378         *
 379         * skip-worktree has the same effect with higher precedence
 380         */
 381        if (!ignore_skip_worktree && ce_skip_worktree(ce))
 382                return 0;
 383        if (!ignore_valid && (ce->ce_flags & CE_VALID))
 384                return 0;
 385        if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID))
 386                return 0;
 387
 388        /*
 389         * Intent-to-add entries have not been added, so the index entry
 390         * by definition never matches what is in the work tree until it
 391         * actually gets added.
 392         */
 393        if (ce_intent_to_add(ce))
 394                return DATA_CHANGED | TYPE_CHANGED | MODE_CHANGED;
 395
 396        changed = ce_match_stat_basic(ce, st);
 397
 398        /*
 399         * Within 1 second of this sequence:
 400         *      echo xyzzy >file && git-update-index --add file
 401         * running this command:
 402         *      echo frotz >file
 403         * would give a falsely clean cache entry.  The mtime and
 404         * length match the cache, and other stat fields do not change.
 405         *
 406         * We could detect this at update-index time (the cache entry
 407         * being registered/updated records the same time as "now")
 408         * and delay the return from git-update-index, but that would
 409         * effectively mean we can make at most one commit per second,
 410         * which is not acceptable.  Instead, we check cache entries
 411         * whose mtime are the same as the index file timestamp more
 412         * carefully than others.
 413         */
 414        if (!changed && is_racy_timestamp(istate, ce)) {
 415                if (assume_racy_is_modified)
 416                        changed |= DATA_CHANGED;
 417                else
 418                        changed |= ce_modified_check_fs(istate, ce, st);
 419        }
 420
 421        return changed;
 422}
 423
 424int ie_modified(struct index_state *istate,
 425                const struct cache_entry *ce,
 426                struct stat *st, unsigned int options)
 427{
 428        int changed, changed_fs;
 429
 430        changed = ie_match_stat(istate, ce, st, options);
 431        if (!changed)
 432                return 0;
 433        /*
 434         * If the mode or type has changed, there's no point in trying
 435         * to refresh the entry - it's not going to match
 436         */
 437        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 438                return changed;
 439
 440        /*
 441         * Immediately after read-tree or update-index --cacheinfo,
 442         * the length field is zero, as we have never even read the
 443         * lstat(2) information once, and we cannot trust DATA_CHANGED
 444         * returned by ie_match_stat() which in turn was returned by
 445         * ce_match_stat_basic() to signal that the filesize of the
 446         * blob changed.  We have to actually go to the filesystem to
 447         * see if the contents match, and if so, should answer "unchanged".
 448         *
 449         * The logic does not apply to gitlinks, as ce_match_stat_basic()
 450         * already has checked the actual HEAD from the filesystem in the
 451         * subproject.  If ie_match_stat() already said it is different,
 452         * then we know it is.
 453         */
 454        if ((changed & DATA_CHANGED) &&
 455            (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0))
 456                return changed;
 457
 458        changed_fs = ce_modified_check_fs(istate, ce, st);
 459        if (changed_fs)
 460                return changed | changed_fs;
 461        return 0;
 462}
 463
 464int base_name_compare(const char *name1, int len1, int mode1,
 465                      const char *name2, int len2, int mode2)
 466{
 467        unsigned char c1, c2;
 468        int len = len1 < len2 ? len1 : len2;
 469        int cmp;
 470
 471        cmp = memcmp(name1, name2, len);
 472        if (cmp)
 473                return cmp;
 474        c1 = name1[len];
 475        c2 = name2[len];
 476        if (!c1 && S_ISDIR(mode1))
 477                c1 = '/';
 478        if (!c2 && S_ISDIR(mode2))
 479                c2 = '/';
 480        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 481}
 482
 483/*
 484 * df_name_compare() is identical to base_name_compare(), except it
 485 * compares conflicting directory/file entries as equal. Note that
 486 * while a directory name compares as equal to a regular file, they
 487 * then individually compare _differently_ to a filename that has
 488 * a dot after the basename (because '\0' < '.' < '/').
 489 *
 490 * This is used by routines that want to traverse the git namespace
 491 * but then handle conflicting entries together when possible.
 492 */
 493int df_name_compare(const char *name1, int len1, int mode1,
 494                    const char *name2, int len2, int mode2)
 495{
 496        int len = len1 < len2 ? len1 : len2, cmp;
 497        unsigned char c1, c2;
 498
 499        cmp = memcmp(name1, name2, len);
 500        if (cmp)
 501                return cmp;
 502        /* Directories and files compare equal (same length, same name) */
 503        if (len1 == len2)
 504                return 0;
 505        c1 = name1[len];
 506        if (!c1 && S_ISDIR(mode1))
 507                c1 = '/';
 508        c2 = name2[len];
 509        if (!c2 && S_ISDIR(mode2))
 510                c2 = '/';
 511        if (c1 == '/' && !c2)
 512                return 0;
 513        if (c2 == '/' && !c1)
 514                return 0;
 515        return c1 - c2;
 516}
 517
 518int name_compare(const char *name1, size_t len1, const char *name2, size_t len2)
 519{
 520        size_t min_len = (len1 < len2) ? len1 : len2;
 521        int cmp = memcmp(name1, name2, min_len);
 522        if (cmp)
 523                return cmp;
 524        if (len1 < len2)
 525                return -1;
 526        if (len1 > len2)
 527                return 1;
 528        return 0;
 529}
 530
 531int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
 532{
 533        int cmp;
 534
 535        cmp = name_compare(name1, len1, name2, len2);
 536        if (cmp)
 537                return cmp;
 538
 539        if (stage1 < stage2)
 540                return -1;
 541        if (stage1 > stage2)
 542                return 1;
 543        return 0;
 544}
 545
 546static int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage)
 547{
 548        int first, last;
 549
 550        first = 0;
 551        last = istate->cache_nr;
 552        while (last > first) {
 553                int next = (last + first) >> 1;
 554                struct cache_entry *ce = istate->cache[next];
 555                int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce));
 556                if (!cmp)
 557                        return next;
 558                if (cmp < 0) {
 559                        last = next;
 560                        continue;
 561                }
 562                first = next+1;
 563        }
 564        return -first-1;
 565}
 566
 567int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 568{
 569        return index_name_stage_pos(istate, name, namelen, 0);
 570}
 571
 572int remove_index_entry_at(struct index_state *istate, int pos)
 573{
 574        struct cache_entry *ce = istate->cache[pos];
 575
 576        record_resolve_undo(istate, ce);
 577        remove_name_hash(istate, ce);
 578        save_or_free_index_entry(istate, ce);
 579        istate->cache_changed |= CE_ENTRY_REMOVED;
 580        istate->cache_nr--;
 581        if (pos >= istate->cache_nr)
 582                return 0;
 583        MOVE_ARRAY(istate->cache + pos, istate->cache + pos + 1,
 584                   istate->cache_nr - pos);
 585        return 1;
 586}
 587
 588/*
 589 * Remove all cache entries marked for removal, that is where
 590 * CE_REMOVE is set in ce_flags.  This is much more effective than
 591 * calling remove_index_entry_at() for each entry to be removed.
 592 */
 593void remove_marked_cache_entries(struct index_state *istate)
 594{
 595        struct cache_entry **ce_array = istate->cache;
 596        unsigned int i, j;
 597
 598        for (i = j = 0; i < istate->cache_nr; i++) {
 599                if (ce_array[i]->ce_flags & CE_REMOVE) {
 600                        remove_name_hash(istate, ce_array[i]);
 601                        save_or_free_index_entry(istate, ce_array[i]);
 602                }
 603                else
 604                        ce_array[j++] = ce_array[i];
 605        }
 606        if (j == istate->cache_nr)
 607                return;
 608        istate->cache_changed |= CE_ENTRY_REMOVED;
 609        istate->cache_nr = j;
 610}
 611
 612int remove_file_from_index(struct index_state *istate, const char *path)
 613{
 614        int pos = index_name_pos(istate, path, strlen(path));
 615        if (pos < 0)
 616                pos = -pos-1;
 617        cache_tree_invalidate_path(istate, path);
 618        untracked_cache_remove_from_index(istate, path);
 619        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 620                remove_index_entry_at(istate, pos);
 621        return 0;
 622}
 623
 624static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 625{
 626        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 627}
 628
 629static int index_name_pos_also_unmerged(struct index_state *istate,
 630        const char *path, int namelen)
 631{
 632        int pos = index_name_pos(istate, path, namelen);
 633        struct cache_entry *ce;
 634
 635        if (pos >= 0)
 636                return pos;
 637
 638        /* maybe unmerged? */
 639        pos = -1 - pos;
 640        if (pos >= istate->cache_nr ||
 641                        compare_name((ce = istate->cache[pos]), path, namelen))
 642                return -1;
 643
 644        /* order of preference: stage 2, 1, 3 */
 645        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 646                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 647                        !compare_name(ce, path, namelen))
 648                pos++;
 649        return pos;
 650}
 651
 652static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 653{
 654        int len = ce_namelen(ce);
 655        return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 656}
 657
 658/*
 659 * If we add a filename that aliases in the cache, we will use the
 660 * name that we already have - but we don't want to update the same
 661 * alias twice, because that implies that there were actually two
 662 * different files with aliasing names!
 663 *
 664 * So we use the CE_ADDED flag to verify that the alias was an old
 665 * one before we accept it as
 666 */
 667static struct cache_entry *create_alias_ce(struct index_state *istate,
 668                                           struct cache_entry *ce,
 669                                           struct cache_entry *alias)
 670{
 671        int len;
 672        struct cache_entry *new_entry;
 673
 674        if (alias->ce_flags & CE_ADDED)
 675                die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 676
 677        /* Ok, create the new entry using the name of the existing alias */
 678        len = ce_namelen(alias);
 679        new_entry = make_empty_cache_entry(istate, len);
 680        memcpy(new_entry->name, alias->name, len);
 681        copy_cache_entry(new_entry, ce);
 682        save_or_free_index_entry(istate, ce);
 683        return new_entry;
 684}
 685
 686void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 687{
 688        struct object_id oid;
 689        if (write_object_file("", 0, blob_type, &oid))
 690                die("cannot create an empty blob in the object database");
 691        oidcpy(&ce->oid, &oid);
 692}
 693
 694int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 695{
 696        int namelen, was_same;
 697        mode_t st_mode = st->st_mode;
 698        struct cache_entry *ce, *alias = NULL;
 699        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE|CE_MATCH_RACY_IS_DIRTY;
 700        int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 701        int pretend = flags & ADD_CACHE_PRETEND;
 702        int intent_only = flags & ADD_CACHE_INTENT;
 703        int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 704                          (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 705        int newflags = HASH_WRITE_OBJECT;
 706
 707        if (flags & HASH_RENORMALIZE)
 708                newflags |= HASH_RENORMALIZE;
 709
 710        if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 711                return error("%s: can only add regular files, symbolic links or git-directories", path);
 712
 713        namelen = strlen(path);
 714        if (S_ISDIR(st_mode)) {
 715                while (namelen && path[namelen-1] == '/')
 716                        namelen--;
 717        }
 718        ce = make_empty_cache_entry(istate, namelen);
 719        memcpy(ce->name, path, namelen);
 720        ce->ce_namelen = namelen;
 721        if (!intent_only)
 722                fill_stat_cache_info(ce, st);
 723        else
 724                ce->ce_flags |= CE_INTENT_TO_ADD;
 725
 726
 727        if (trust_executable_bit && has_symlinks) {
 728                ce->ce_mode = create_ce_mode(st_mode);
 729        } else {
 730                /* If there is an existing entry, pick the mode bits and type
 731                 * from it, otherwise assume unexecutable regular file.
 732                 */
 733                struct cache_entry *ent;
 734                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 735
 736                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 737                ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 738        }
 739
 740        /* When core.ignorecase=true, determine if a directory of the same name but differing
 741         * case already exists within the Git repository.  If it does, ensure the directory
 742         * case of the file being added to the repository matches (is folded into) the existing
 743         * entry's directory case.
 744         */
 745        if (ignore_case) {
 746                adjust_dirname_case(istate, ce->name);
 747        }
 748        if (!(flags & HASH_RENORMALIZE)) {
 749                alias = index_file_exists(istate, ce->name,
 750                                          ce_namelen(ce), ignore_case);
 751                if (alias &&
 752                    !ce_stage(alias) &&
 753                    !ie_match_stat(istate, alias, st, ce_option)) {
 754                        /* Nothing changed, really */
 755                        if (!S_ISGITLINK(alias->ce_mode))
 756                                ce_mark_uptodate(alias);
 757                        alias->ce_flags |= CE_ADDED;
 758
 759                        discard_cache_entry(ce);
 760                        return 0;
 761                }
 762        }
 763        if (!intent_only) {
 764                if (index_path(istate, &ce->oid, path, st, newflags)) {
 765                        discard_cache_entry(ce);
 766                        return error("unable to index file %s", path);
 767                }
 768        } else
 769                set_object_name_for_intent_to_add_entry(ce);
 770
 771        if (ignore_case && alias && different_name(ce, alias))
 772                ce = create_alias_ce(istate, ce, alias);
 773        ce->ce_flags |= CE_ADDED;
 774
 775        /* It was suspected to be racily clean, but it turns out to be Ok */
 776        was_same = (alias &&
 777                    !ce_stage(alias) &&
 778                    oideq(&alias->oid, &ce->oid) &&
 779                    ce->ce_mode == alias->ce_mode);
 780
 781        if (pretend)
 782                discard_cache_entry(ce);
 783        else if (add_index_entry(istate, ce, add_option)) {
 784                discard_cache_entry(ce);
 785                return error("unable to add %s to index", path);
 786        }
 787        if (verbose && !was_same)
 788                printf("add '%s'\n", path);
 789        return 0;
 790}
 791
 792int add_file_to_index(struct index_state *istate, const char *path, int flags)
 793{
 794        struct stat st;
 795        if (lstat(path, &st))
 796                die_errno("unable to stat '%s'", path);
 797        return add_to_index(istate, path, &st, flags);
 798}
 799
 800struct cache_entry *make_empty_cache_entry(struct index_state *istate, size_t len)
 801{
 802        return mem_pool__ce_calloc(find_mem_pool(istate), len);
 803}
 804
 805struct cache_entry *make_empty_transient_cache_entry(size_t len)
 806{
 807        return xcalloc(1, cache_entry_size(len));
 808}
 809
 810struct cache_entry *make_cache_entry(struct index_state *istate,
 811                                     unsigned int mode,
 812                                     const struct object_id *oid,
 813                                     const char *path,
 814                                     int stage,
 815                                     unsigned int refresh_options)
 816{
 817        struct cache_entry *ce, *ret;
 818        int len;
 819
 820        if (!verify_path(path, mode)) {
 821                error("Invalid path '%s'", path);
 822                return NULL;
 823        }
 824
 825        len = strlen(path);
 826        ce = make_empty_cache_entry(istate, len);
 827
 828        oidcpy(&ce->oid, oid);
 829        memcpy(ce->name, path, len);
 830        ce->ce_flags = create_ce_flags(stage);
 831        ce->ce_namelen = len;
 832        ce->ce_mode = create_ce_mode(mode);
 833
 834        ret = refresh_cache_entry(istate, ce, refresh_options);
 835        if (ret != ce)
 836                discard_cache_entry(ce);
 837        return ret;
 838}
 839
 840struct cache_entry *make_transient_cache_entry(unsigned int mode, const struct object_id *oid,
 841                                               const char *path, int stage)
 842{
 843        struct cache_entry *ce;
 844        int len;
 845
 846        if (!verify_path(path, mode)) {
 847                error("Invalid path '%s'", path);
 848                return NULL;
 849        }
 850
 851        len = strlen(path);
 852        ce = make_empty_transient_cache_entry(len);
 853
 854        oidcpy(&ce->oid, oid);
 855        memcpy(ce->name, path, len);
 856        ce->ce_flags = create_ce_flags(stage);
 857        ce->ce_namelen = len;
 858        ce->ce_mode = create_ce_mode(mode);
 859
 860        return ce;
 861}
 862
 863/*
 864 * Chmod an index entry with either +x or -x.
 865 *
 866 * Returns -1 if the chmod for the particular cache entry failed (if it's
 867 * not a regular file), -2 if an invalid flip argument is passed in, 0
 868 * otherwise.
 869 */
 870int chmod_index_entry(struct index_state *istate, struct cache_entry *ce,
 871                      char flip)
 872{
 873        if (!S_ISREG(ce->ce_mode))
 874                return -1;
 875        switch (flip) {
 876        case '+':
 877                ce->ce_mode |= 0111;
 878                break;
 879        case '-':
 880                ce->ce_mode &= ~0111;
 881                break;
 882        default:
 883                return -2;
 884        }
 885        cache_tree_invalidate_path(istate, ce->name);
 886        ce->ce_flags |= CE_UPDATE_IN_BASE;
 887        mark_fsmonitor_invalid(istate, ce);
 888        istate->cache_changed |= CE_ENTRY_CHANGED;
 889
 890        return 0;
 891}
 892
 893int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 894{
 895        int len = ce_namelen(a);
 896        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 897}
 898
 899/*
 900 * We fundamentally don't like some paths: we don't want
 901 * dot or dot-dot anywhere, and for obvious reasons don't
 902 * want to recurse into ".git" either.
 903 *
 904 * Also, we don't want double slashes or slashes at the
 905 * end that can make pathnames ambiguous.
 906 */
 907static int verify_dotfile(const char *rest, unsigned mode)
 908{
 909        /*
 910         * The first character was '.', but that
 911         * has already been discarded, we now test
 912         * the rest.
 913         */
 914
 915        /* "." is not allowed */
 916        if (*rest == '\0' || is_dir_sep(*rest))
 917                return 0;
 918
 919        switch (*rest) {
 920        /*
 921         * ".git" followed by NUL or slash is bad. Note that we match
 922         * case-insensitively here, even if ignore_case is not set.
 923         * This outlaws ".GIT" everywhere out of an abundance of caution,
 924         * since there's really no good reason to allow it.
 925         *
 926         * Once we've seen ".git", we can also find ".gitmodules", etc (also
 927         * case-insensitively).
 928         */
 929        case 'g':
 930        case 'G':
 931                if (rest[1] != 'i' && rest[1] != 'I')
 932                        break;
 933                if (rest[2] != 't' && rest[2] != 'T')
 934                        break;
 935                if (rest[3] == '\0' || is_dir_sep(rest[3]))
 936                        return 0;
 937                if (S_ISLNK(mode)) {
 938                        rest += 3;
 939                        if (skip_iprefix(rest, "modules", &rest) &&
 940                            (*rest == '\0' || is_dir_sep(*rest)))
 941                                return 0;
 942                }
 943                break;
 944        case '.':
 945                if (rest[1] == '\0' || is_dir_sep(rest[1]))
 946                        return 0;
 947        }
 948        return 1;
 949}
 950
 951int verify_path(const char *path, unsigned mode)
 952{
 953        char c;
 954
 955        if (has_dos_drive_prefix(path))
 956                return 0;
 957
 958        goto inside;
 959        for (;;) {
 960                if (!c)
 961                        return 1;
 962                if (is_dir_sep(c)) {
 963inside:
 964                        if (protect_hfs) {
 965                                if (is_hfs_dotgit(path))
 966                                        return 0;
 967                                if (S_ISLNK(mode)) {
 968                                        if (is_hfs_dotgitmodules(path))
 969                                                return 0;
 970                                }
 971                        }
 972                        if (protect_ntfs) {
 973                                if (is_ntfs_dotgit(path))
 974                                        return 0;
 975                                if (S_ISLNK(mode)) {
 976                                        if (is_ntfs_dotgitmodules(path))
 977                                                return 0;
 978                                }
 979                        }
 980
 981                        c = *path++;
 982                        if ((c == '.' && !verify_dotfile(path, mode)) ||
 983                            is_dir_sep(c) || c == '\0')
 984                                return 0;
 985                }
 986                c = *path++;
 987        }
 988}
 989
 990/*
 991 * Do we have another file that has the beginning components being a
 992 * proper superset of the name we're trying to add?
 993 */
 994static int has_file_name(struct index_state *istate,
 995                         const struct cache_entry *ce, int pos, int ok_to_replace)
 996{
 997        int retval = 0;
 998        int len = ce_namelen(ce);
 999        int stage = ce_stage(ce);
1000        const char *name = ce->name;
1001
1002        while (pos < istate->cache_nr) {
1003                struct cache_entry *p = istate->cache[pos++];
1004
1005                if (len >= ce_namelen(p))
1006                        break;
1007                if (memcmp(name, p->name, len))
1008                        break;
1009                if (ce_stage(p) != stage)
1010                        continue;
1011                if (p->name[len] != '/')
1012                        continue;
1013                if (p->ce_flags & CE_REMOVE)
1014                        continue;
1015                retval = -1;
1016                if (!ok_to_replace)
1017                        break;
1018                remove_index_entry_at(istate, --pos);
1019        }
1020        return retval;
1021}
1022
1023
1024/*
1025 * Like strcmp(), but also return the offset of the first change.
1026 * If strings are equal, return the length.
1027 */
1028int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
1029{
1030        size_t k;
1031
1032        if (!first_change)
1033                return strcmp(s1, s2);
1034
1035        for (k = 0; s1[k] == s2[k]; k++)
1036                if (s1[k] == '\0')
1037                        break;
1038
1039        *first_change = k;
1040        return (unsigned char)s1[k] - (unsigned char)s2[k];
1041}
1042
1043/*
1044 * Do we have another file with a pathname that is a proper
1045 * subset of the name we're trying to add?
1046 *
1047 * That is, is there another file in the index with a path
1048 * that matches a sub-directory in the given entry?
1049 */
1050static int has_dir_name(struct index_state *istate,
1051                        const struct cache_entry *ce, int pos, int ok_to_replace)
1052{
1053        int retval = 0;
1054        int stage = ce_stage(ce);
1055        const char *name = ce->name;
1056        const char *slash = name + ce_namelen(ce);
1057        size_t len_eq_last;
1058        int cmp_last = 0;
1059
1060        /*
1061         * We are frequently called during an iteration on a sorted
1062         * list of pathnames and while building a new index.  Therefore,
1063         * there is a high probability that this entry will eventually
1064         * be appended to the index, rather than inserted in the middle.
1065         * If we can confirm that, we can avoid binary searches on the
1066         * components of the pathname.
1067         *
1068         * Compare the entry's full path with the last path in the index.
1069         */
1070        if (istate->cache_nr > 0) {
1071                cmp_last = strcmp_offset(name,
1072                        istate->cache[istate->cache_nr - 1]->name,
1073                        &len_eq_last);
1074                if (cmp_last > 0) {
1075                        if (len_eq_last == 0) {
1076                                /*
1077                                 * The entry sorts AFTER the last one in the
1078                                 * index and their paths have no common prefix,
1079                                 * so there cannot be a F/D conflict.
1080                                 */
1081                                return retval;
1082                        } else {
1083                                /*
1084                                 * The entry sorts AFTER the last one in the
1085                                 * index, but has a common prefix.  Fall through
1086                                 * to the loop below to disect the entry's path
1087                                 * and see where the difference is.
1088                                 */
1089                        }
1090                } else if (cmp_last == 0) {
1091                        /*
1092                         * The entry exactly matches the last one in the
1093                         * index, but because of multiple stage and CE_REMOVE
1094                         * items, we fall through and let the regular search
1095                         * code handle it.
1096                         */
1097                }
1098        }
1099
1100        for (;;) {
1101                size_t len;
1102
1103                for (;;) {
1104                        if (*--slash == '/')
1105                                break;
1106                        if (slash <= ce->name)
1107                                return retval;
1108                }
1109                len = slash - name;
1110
1111                if (cmp_last > 0) {
1112                        /*
1113                         * (len + 1) is a directory boundary (including
1114                         * the trailing slash).  And since the loop is
1115                         * decrementing "slash", the first iteration is
1116                         * the longest directory prefix; subsequent
1117                         * iterations consider parent directories.
1118                         */
1119
1120                        if (len + 1 <= len_eq_last) {
1121                                /*
1122                                 * The directory prefix (including the trailing
1123                                 * slash) also appears as a prefix in the last
1124                                 * entry, so the remainder cannot collide (because
1125                                 * strcmp said the whole path was greater).
1126                                 *
1127                                 * EQ: last: xxx/A
1128                                 *     this: xxx/B
1129                                 *
1130                                 * LT: last: xxx/file_A
1131                                 *     this: xxx/file_B
1132                                 */
1133                                return retval;
1134                        }
1135
1136                        if (len > len_eq_last) {
1137                                /*
1138                                 * This part of the directory prefix (excluding
1139                                 * the trailing slash) is longer than the known
1140                                 * equal portions, so this sub-directory cannot
1141                                 * collide with a file.
1142                                 *
1143                                 * GT: last: xxxA
1144                                 *     this: xxxB/file
1145                                 */
1146                                return retval;
1147                        }
1148
1149                        if (istate->cache_nr > 0 &&
1150                                ce_namelen(istate->cache[istate->cache_nr - 1]) > len) {
1151                                /*
1152                                 * The directory prefix lines up with part of
1153                                 * a longer file or directory name, but sorts
1154                                 * after it, so this sub-directory cannot
1155                                 * collide with a file.
1156                                 *
1157                                 * last: xxx/yy-file (because '-' sorts before '/')
1158                                 * this: xxx/yy/abc
1159                                 */
1160                                return retval;
1161                        }
1162
1163                        /*
1164                         * This is a possible collision. Fall through and
1165                         * let the regular search code handle it.
1166                         *
1167                         * last: xxx
1168                         * this: xxx/file
1169                         */
1170                }
1171
1172                pos = index_name_stage_pos(istate, name, len, stage);
1173                if (pos >= 0) {
1174                        /*
1175                         * Found one, but not so fast.  This could
1176                         * be a marker that says "I was here, but
1177                         * I am being removed".  Such an entry is
1178                         * not a part of the resulting tree, and
1179                         * it is Ok to have a directory at the same
1180                         * path.
1181                         */
1182                        if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
1183                                retval = -1;
1184                                if (!ok_to_replace)
1185                                        break;
1186                                remove_index_entry_at(istate, pos);
1187                                continue;
1188                        }
1189                }
1190                else
1191                        pos = -pos-1;
1192
1193                /*
1194                 * Trivial optimization: if we find an entry that
1195                 * already matches the sub-directory, then we know
1196                 * we're ok, and we can exit.
1197                 */
1198                while (pos < istate->cache_nr) {
1199                        struct cache_entry *p = istate->cache[pos];
1200                        if ((ce_namelen(p) <= len) ||
1201                            (p->name[len] != '/') ||
1202                            memcmp(p->name, name, len))
1203                                break; /* not our subdirectory */
1204                        if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
1205                                /*
1206                                 * p is at the same stage as our entry, and
1207                                 * is a subdirectory of what we are looking
1208                                 * at, so we cannot have conflicts at our
1209                                 * level or anything shorter.
1210                                 */
1211                                return retval;
1212                        pos++;
1213                }
1214        }
1215        return retval;
1216}
1217
1218/* We may be in a situation where we already have path/file and path
1219 * is being added, or we already have path and path/file is being
1220 * added.  Either one would result in a nonsense tree that has path
1221 * twice when git-write-tree tries to write it out.  Prevent it.
1222 *
1223 * If ok-to-replace is specified, we remove the conflicting entries
1224 * from the cache so the caller should recompute the insert position.
1225 * When this happens, we return non-zero.
1226 */
1227static int check_file_directory_conflict(struct index_state *istate,
1228                                         const struct cache_entry *ce,
1229                                         int pos, int ok_to_replace)
1230{
1231        int retval;
1232
1233        /*
1234         * When ce is an "I am going away" entry, we allow it to be added
1235         */
1236        if (ce->ce_flags & CE_REMOVE)
1237                return 0;
1238
1239        /*
1240         * We check if the path is a sub-path of a subsequent pathname
1241         * first, since removing those will not change the position
1242         * in the array.
1243         */
1244        retval = has_file_name(istate, ce, pos, ok_to_replace);
1245
1246        /*
1247         * Then check if the path might have a clashing sub-directory
1248         * before it.
1249         */
1250        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
1251}
1252
1253static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
1254{
1255        int pos;
1256        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
1257        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
1258        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
1259        int new_only = option & ADD_CACHE_NEW_ONLY;
1260
1261        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1262                cache_tree_invalidate_path(istate, ce->name);
1263
1264        /*
1265         * If this entry's path sorts after the last entry in the index,
1266         * we can avoid searching for it.
1267         */
1268        if (istate->cache_nr > 0 &&
1269                strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
1270                pos = -istate->cache_nr - 1;
1271        else
1272                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1273
1274        /* existing match? Just replace it. */
1275        if (pos >= 0) {
1276                if (!new_only)
1277                        replace_index_entry(istate, pos, ce);
1278                return 0;
1279        }
1280        pos = -pos-1;
1281
1282        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1283                untracked_cache_add_to_index(istate, ce->name);
1284
1285        /*
1286         * Inserting a merged entry ("stage 0") into the index
1287         * will always replace all non-merged entries..
1288         */
1289        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
1290                while (ce_same_name(istate->cache[pos], ce)) {
1291                        ok_to_add = 1;
1292                        if (!remove_index_entry_at(istate, pos))
1293                                break;
1294                }
1295        }
1296
1297        if (!ok_to_add)
1298                return -1;
1299        if (!verify_path(ce->name, ce->ce_mode))
1300                return error("Invalid path '%s'", ce->name);
1301
1302        if (!skip_df_check &&
1303            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
1304                if (!ok_to_replace)
1305                        return error("'%s' appears as both a file and as a directory",
1306                                     ce->name);
1307                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1308                pos = -pos-1;
1309        }
1310        return pos + 1;
1311}
1312
1313int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
1314{
1315        int pos;
1316
1317        if (option & ADD_CACHE_JUST_APPEND)
1318                pos = istate->cache_nr;
1319        else {
1320                int ret;
1321                ret = add_index_entry_with_check(istate, ce, option);
1322                if (ret <= 0)
1323                        return ret;
1324                pos = ret - 1;
1325        }
1326
1327        /* Make sure the array is big enough .. */
1328        ALLOC_GROW(istate->cache, istate->cache_nr + 1, istate->cache_alloc);
1329
1330        /* Add it in.. */
1331        istate->cache_nr++;
1332        if (istate->cache_nr > pos + 1)
1333                MOVE_ARRAY(istate->cache + pos + 1, istate->cache + pos,
1334                           istate->cache_nr - pos - 1);
1335        set_index_entry(istate, pos, ce);
1336        istate->cache_changed |= CE_ENTRY_ADDED;
1337        return 0;
1338}
1339
1340/*
1341 * "refresh" does not calculate a new sha1 file or bring the
1342 * cache up-to-date for mode/content changes. But what it
1343 * _does_ do is to "re-match" the stat information of a file
1344 * with the cache, so that you can refresh the cache for a
1345 * file that hasn't been changed but where the stat entry is
1346 * out of date.
1347 *
1348 * For example, you'd want to do this after doing a "git-read-tree",
1349 * to link up the stat cache details with the proper files.
1350 */
1351static struct cache_entry *refresh_cache_ent(struct index_state *istate,
1352                                             struct cache_entry *ce,
1353                                             unsigned int options, int *err,
1354                                             int *changed_ret)
1355{
1356        struct stat st;
1357        struct cache_entry *updated;
1358        int changed;
1359        int refresh = options & CE_MATCH_REFRESH;
1360        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
1361        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
1362        int ignore_missing = options & CE_MATCH_IGNORE_MISSING;
1363        int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR;
1364
1365        if (!refresh || ce_uptodate(ce))
1366                return ce;
1367
1368        if (!ignore_fsmonitor)
1369                refresh_fsmonitor(istate);
1370        /*
1371         * CE_VALID or CE_SKIP_WORKTREE means the user promised us
1372         * that the change to the work tree does not matter and told
1373         * us not to worry.
1374         */
1375        if (!ignore_skip_worktree && ce_skip_worktree(ce)) {
1376                ce_mark_uptodate(ce);
1377                return ce;
1378        }
1379        if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
1380                ce_mark_uptodate(ce);
1381                return ce;
1382        }
1383        if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID)) {
1384                ce_mark_uptodate(ce);
1385                return ce;
1386        }
1387
1388        if (has_symlink_leading_path(ce->name, ce_namelen(ce))) {
1389                if (ignore_missing)
1390                        return ce;
1391                if (err)
1392                        *err = ENOENT;
1393                return NULL;
1394        }
1395
1396        if (lstat(ce->name, &st) < 0) {
1397                if (ignore_missing && errno == ENOENT)
1398                        return ce;
1399                if (err)
1400                        *err = errno;
1401                return NULL;
1402        }
1403
1404        changed = ie_match_stat(istate, ce, &st, options);
1405        if (changed_ret)
1406                *changed_ret = changed;
1407        if (!changed) {
1408                /*
1409                 * The path is unchanged.  If we were told to ignore
1410                 * valid bit, then we did the actual stat check and
1411                 * found that the entry is unmodified.  If the entry
1412                 * is not marked VALID, this is the place to mark it
1413                 * valid again, under "assume unchanged" mode.
1414                 */
1415                if (ignore_valid && assume_unchanged &&
1416                    !(ce->ce_flags & CE_VALID))
1417                        ; /* mark this one VALID again */
1418                else {
1419                        /*
1420                         * We do not mark the index itself "modified"
1421                         * because CE_UPTODATE flag is in-core only;
1422                         * we are not going to write this change out.
1423                         */
1424                        if (!S_ISGITLINK(ce->ce_mode)) {
1425                                ce_mark_uptodate(ce);
1426                                mark_fsmonitor_valid(ce);
1427                        }
1428                        return ce;
1429                }
1430        }
1431
1432        if (ie_modified(istate, ce, &st, options)) {
1433                if (err)
1434                        *err = EINVAL;
1435                return NULL;
1436        }
1437
1438        updated = make_empty_cache_entry(istate, ce_namelen(ce));
1439        copy_cache_entry(updated, ce);
1440        memcpy(updated->name, ce->name, ce->ce_namelen + 1);
1441        fill_stat_cache_info(updated, &st);
1442        /*
1443         * If ignore_valid is not set, we should leave CE_VALID bit
1444         * alone.  Otherwise, paths marked with --no-assume-unchanged
1445         * (i.e. things to be edited) will reacquire CE_VALID bit
1446         * automatically, which is not really what we want.
1447         */
1448        if (!ignore_valid && assume_unchanged &&
1449            !(ce->ce_flags & CE_VALID))
1450                updated->ce_flags &= ~CE_VALID;
1451
1452        /* istate->cache_changed is updated in the caller */
1453        return updated;
1454}
1455
1456static void show_file(const char * fmt, const char * name, int in_porcelain,
1457                      int * first, const char *header_msg)
1458{
1459        if (in_porcelain && *first && header_msg) {
1460                printf("%s\n", header_msg);
1461                *first = 0;
1462        }
1463        printf(fmt, name);
1464}
1465
1466int refresh_index(struct index_state *istate, unsigned int flags,
1467                  const struct pathspec *pathspec,
1468                  char *seen, const char *header_msg)
1469{
1470        int i;
1471        int has_errors = 0;
1472        int really = (flags & REFRESH_REALLY) != 0;
1473        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
1474        int quiet = (flags & REFRESH_QUIET) != 0;
1475        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
1476        int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
1477        int first = 1;
1478        int in_porcelain = (flags & REFRESH_IN_PORCELAIN);
1479        unsigned int options = (CE_MATCH_REFRESH |
1480                                (really ? CE_MATCH_IGNORE_VALID : 0) |
1481                                (not_new ? CE_MATCH_IGNORE_MISSING : 0));
1482        const char *modified_fmt;
1483        const char *deleted_fmt;
1484        const char *typechange_fmt;
1485        const char *added_fmt;
1486        const char *unmerged_fmt;
1487        struct progress *progress = NULL;
1488
1489        if (flags & REFRESH_PROGRESS && isatty(2))
1490                progress = start_delayed_progress(_("Refresh index"),
1491                                                  istate->cache_nr);
1492
1493        trace_performance_enter();
1494        modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
1495        deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
1496        typechange_fmt = (in_porcelain ? "T\t%s\n" : "%s needs update\n");
1497        added_fmt = (in_porcelain ? "A\t%s\n" : "%s needs update\n");
1498        unmerged_fmt = (in_porcelain ? "U\t%s\n" : "%s: needs merge\n");
1499        /*
1500         * Use the multi-threaded preload_index() to refresh most of the
1501         * cache entries quickly then in the single threaded loop below,
1502         * we only have to do the special cases that are left.
1503         */
1504        preload_index(istate, pathspec, 0);
1505        for (i = 0; i < istate->cache_nr; i++) {
1506                struct cache_entry *ce, *new_entry;
1507                int cache_errno = 0;
1508                int changed = 0;
1509                int filtered = 0;
1510
1511                ce = istate->cache[i];
1512                if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
1513                        continue;
1514
1515                if (pathspec && !ce_path_match(istate, ce, pathspec, seen))
1516                        filtered = 1;
1517
1518                if (ce_stage(ce)) {
1519                        while ((i < istate->cache_nr) &&
1520                               ! strcmp(istate->cache[i]->name, ce->name))
1521                                i++;
1522                        i--;
1523                        if (allow_unmerged)
1524                                continue;
1525                        if (!filtered)
1526                                show_file(unmerged_fmt, ce->name, in_porcelain,
1527                                          &first, header_msg);
1528                        has_errors = 1;
1529                        continue;
1530                }
1531
1532                if (filtered)
1533                        continue;
1534
1535                new_entry = refresh_cache_ent(istate, ce, options, &cache_errno, &changed);
1536                if (new_entry == ce)
1537                        continue;
1538                if (progress)
1539                        display_progress(progress, i);
1540                if (!new_entry) {
1541                        const char *fmt;
1542
1543                        if (really && cache_errno == EINVAL) {
1544                                /* If we are doing --really-refresh that
1545                                 * means the index is not valid anymore.
1546                                 */
1547                                ce->ce_flags &= ~CE_VALID;
1548                                ce->ce_flags |= CE_UPDATE_IN_BASE;
1549                                mark_fsmonitor_invalid(istate, ce);
1550                                istate->cache_changed |= CE_ENTRY_CHANGED;
1551                        }
1552                        if (quiet)
1553                                continue;
1554
1555                        if (cache_errno == ENOENT)
1556                                fmt = deleted_fmt;
1557                        else if (ce_intent_to_add(ce))
1558                                fmt = added_fmt; /* must be before other checks */
1559                        else if (changed & TYPE_CHANGED)
1560                                fmt = typechange_fmt;
1561                        else
1562                                fmt = modified_fmt;
1563                        show_file(fmt,
1564                                  ce->name, in_porcelain, &first, header_msg);
1565                        has_errors = 1;
1566                        continue;
1567                }
1568
1569                replace_index_entry(istate, i, new_entry);
1570        }
1571        if (progress) {
1572                display_progress(progress, istate->cache_nr);
1573                stop_progress(&progress);
1574        }
1575        trace_performance_leave("refresh index");
1576        return has_errors;
1577}
1578
1579struct cache_entry *refresh_cache_entry(struct index_state *istate,
1580                                        struct cache_entry *ce,
1581                                        unsigned int options)
1582{
1583        return refresh_cache_ent(istate, ce, options, NULL, NULL);
1584}
1585
1586
1587/*****************************************************************
1588 * Index File I/O
1589 *****************************************************************/
1590
1591#define INDEX_FORMAT_DEFAULT 3
1592
1593static unsigned int get_index_format_default(void)
1594{
1595        char *envversion = getenv("GIT_INDEX_VERSION");
1596        char *endp;
1597        int value;
1598        unsigned int version = INDEX_FORMAT_DEFAULT;
1599
1600        if (!envversion) {
1601                if (!git_config_get_int("index.version", &value))
1602                        version = value;
1603                if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1604                        warning(_("index.version set, but the value is invalid.\n"
1605                                  "Using version %i"), INDEX_FORMAT_DEFAULT);
1606                        return INDEX_FORMAT_DEFAULT;
1607                }
1608                return version;
1609        }
1610
1611        version = strtoul(envversion, &endp, 10);
1612        if (*endp ||
1613            version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1614                warning(_("GIT_INDEX_VERSION set, but the value is invalid.\n"
1615                          "Using version %i"), INDEX_FORMAT_DEFAULT);
1616                version = INDEX_FORMAT_DEFAULT;
1617        }
1618        return version;
1619}
1620
1621/*
1622 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
1623 * Again - this is just a (very strong in practice) heuristic that
1624 * the inode hasn't changed.
1625 *
1626 * We save the fields in big-endian order to allow using the
1627 * index file over NFS transparently.
1628 */
1629struct ondisk_cache_entry {
1630        struct cache_time ctime;
1631        struct cache_time mtime;
1632        uint32_t dev;
1633        uint32_t ino;
1634        uint32_t mode;
1635        uint32_t uid;
1636        uint32_t gid;
1637        uint32_t size;
1638        unsigned char sha1[20];
1639        uint16_t flags;
1640        char name[FLEX_ARRAY]; /* more */
1641};
1642
1643/*
1644 * This struct is used when CE_EXTENDED bit is 1
1645 * The struct must match ondisk_cache_entry exactly from
1646 * ctime till flags
1647 */
1648struct ondisk_cache_entry_extended {
1649        struct cache_time ctime;
1650        struct cache_time mtime;
1651        uint32_t dev;
1652        uint32_t ino;
1653        uint32_t mode;
1654        uint32_t uid;
1655        uint32_t gid;
1656        uint32_t size;
1657        unsigned char sha1[20];
1658        uint16_t flags;
1659        uint16_t flags2;
1660        char name[FLEX_ARRAY]; /* more */
1661};
1662
1663/* These are only used for v3 or lower */
1664#define align_padding_size(size, len) ((size + (len) + 8) & ~7) - (size + len)
1665#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
1666#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
1667#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
1668#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
1669                            ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
1670                            ondisk_cache_entry_size(ce_namelen(ce)))
1671
1672/* Allow fsck to force verification of the index checksum. */
1673int verify_index_checksum;
1674
1675/* Allow fsck to force verification of the cache entry order. */
1676int verify_ce_order;
1677
1678static int verify_hdr(const struct cache_header *hdr, unsigned long size)
1679{
1680        git_hash_ctx c;
1681        unsigned char hash[GIT_MAX_RAWSZ];
1682        int hdr_version;
1683
1684        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1685                return error("bad signature");
1686        hdr_version = ntohl(hdr->hdr_version);
1687        if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
1688                return error("bad index version %d", hdr_version);
1689
1690        if (!verify_index_checksum)
1691                return 0;
1692
1693        the_hash_algo->init_fn(&c);
1694        the_hash_algo->update_fn(&c, hdr, size - the_hash_algo->rawsz);
1695        the_hash_algo->final_fn(hash, &c);
1696        if (!hasheq(hash, (unsigned char *)hdr + size - the_hash_algo->rawsz))
1697                return error("bad index file sha1 signature");
1698        return 0;
1699}
1700
1701static int read_index_extension(struct index_state *istate,
1702                                const char *ext, const char *data, unsigned long sz)
1703{
1704        switch (CACHE_EXT(ext)) {
1705        case CACHE_EXT_TREE:
1706                istate->cache_tree = cache_tree_read(data, sz);
1707                break;
1708        case CACHE_EXT_RESOLVE_UNDO:
1709                istate->resolve_undo = resolve_undo_read(data, sz);
1710                break;
1711        case CACHE_EXT_LINK:
1712                if (read_link_extension(istate, data, sz))
1713                        return -1;
1714                break;
1715        case CACHE_EXT_UNTRACKED:
1716                istate->untracked = read_untracked_extension(data, sz);
1717                break;
1718        case CACHE_EXT_FSMONITOR:
1719                read_fsmonitor_extension(istate, data, sz);
1720                break;
1721        case CACHE_EXT_ENDOFINDEXENTRIES:
1722        case CACHE_EXT_INDEXENTRYOFFSETTABLE:
1723                /* already handled in do_read_index() */
1724                break;
1725        default:
1726                if (*ext < 'A' || 'Z' < *ext)
1727                        return error("index uses %.4s extension, which we do not understand",
1728                                     ext);
1729                fprintf(stderr, "ignoring %.4s extension\n", ext);
1730                break;
1731        }
1732        return 0;
1733}
1734
1735int hold_locked_index(struct lock_file *lk, int lock_flags)
1736{
1737        return hold_lock_file_for_update(lk, get_index_file(), lock_flags);
1738}
1739
1740int read_index(struct index_state *istate)
1741{
1742        return read_index_from(istate, get_index_file(), get_git_dir());
1743}
1744
1745static struct cache_entry *create_from_disk(struct mem_pool *ce_mem_pool,
1746                                            unsigned int version,
1747                                            struct ondisk_cache_entry *ondisk,
1748                                            unsigned long *ent_size,
1749                                            const struct cache_entry *previous_ce)
1750{
1751        struct cache_entry *ce;
1752        size_t len;
1753        const char *name;
1754        unsigned int flags;
1755        size_t copy_len = 0;
1756        /*
1757         * Adjacent cache entries tend to share the leading paths, so it makes
1758         * sense to only store the differences in later entries.  In the v4
1759         * on-disk format of the index, each on-disk cache entry stores the
1760         * number of bytes to be stripped from the end of the previous name,
1761         * and the bytes to append to the result, to come up with its name.
1762         */
1763        int expand_name_field = version == 4;
1764
1765        /* On-disk flags are just 16 bits */
1766        flags = get_be16(&ondisk->flags);
1767        len = flags & CE_NAMEMASK;
1768
1769        if (flags & CE_EXTENDED) {
1770                struct ondisk_cache_entry_extended *ondisk2;
1771                int extended_flags;
1772                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1773                extended_flags = get_be16(&ondisk2->flags2) << 16;
1774                /* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
1775                if (extended_flags & ~CE_EXTENDED_FLAGS)
1776                        die("Unknown index entry format %08x", extended_flags);
1777                flags |= extended_flags;
1778                name = ondisk2->name;
1779        }
1780        else
1781                name = ondisk->name;
1782
1783        if (expand_name_field) {
1784                const unsigned char *cp = (const unsigned char *)name;
1785                size_t strip_len, previous_len;
1786
1787                /* If we're at the begining of a block, ignore the previous name */
1788                strip_len = decode_varint(&cp);
1789                if (previous_ce) {
1790                        previous_len = previous_ce->ce_namelen;
1791                        if (previous_len < strip_len)
1792                                die(_("malformed name field in the index, near path '%s'"),
1793                                        previous_ce->name);
1794                        copy_len = previous_len - strip_len;
1795                }
1796                name = (const char *)cp;
1797        }
1798
1799        if (len == CE_NAMEMASK) {
1800                len = strlen(name);
1801                if (expand_name_field)
1802                        len += copy_len;
1803        }
1804
1805        ce = mem_pool__ce_alloc(ce_mem_pool, len);
1806
1807        ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
1808        ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
1809        ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
1810        ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
1811        ce->ce_stat_data.sd_dev   = get_be32(&ondisk->dev);
1812        ce->ce_stat_data.sd_ino   = get_be32(&ondisk->ino);
1813        ce->ce_mode  = get_be32(&ondisk->mode);
1814        ce->ce_stat_data.sd_uid   = get_be32(&ondisk->uid);
1815        ce->ce_stat_data.sd_gid   = get_be32(&ondisk->gid);
1816        ce->ce_stat_data.sd_size  = get_be32(&ondisk->size);
1817        ce->ce_flags = flags & ~CE_NAMEMASK;
1818        ce->ce_namelen = len;
1819        ce->index = 0;
1820        hashcpy(ce->oid.hash, ondisk->sha1);
1821
1822        if (expand_name_field) {
1823                if (copy_len)
1824                        memcpy(ce->name, previous_ce->name, copy_len);
1825                memcpy(ce->name + copy_len, name, len + 1 - copy_len);
1826                *ent_size = (name - ((char *)ondisk)) + len + 1 - copy_len;
1827        } else {
1828                memcpy(ce->name, name, len + 1);
1829                *ent_size = ondisk_ce_size(ce);
1830        }
1831        return ce;
1832}
1833
1834static void check_ce_order(struct index_state *istate)
1835{
1836        unsigned int i;
1837
1838        if (!verify_ce_order)
1839                return;
1840
1841        for (i = 1; i < istate->cache_nr; i++) {
1842                struct cache_entry *ce = istate->cache[i - 1];
1843                struct cache_entry *next_ce = istate->cache[i];
1844                int name_compare = strcmp(ce->name, next_ce->name);
1845
1846                if (0 < name_compare)
1847                        die("unordered stage entries in index");
1848                if (!name_compare) {
1849                        if (!ce_stage(ce))
1850                                die("multiple stage entries for merged file '%s'",
1851                                    ce->name);
1852                        if (ce_stage(ce) > ce_stage(next_ce))
1853                                die("unordered stage entries for '%s'",
1854                                    ce->name);
1855                }
1856        }
1857}
1858
1859static void tweak_untracked_cache(struct index_state *istate)
1860{
1861        switch (git_config_get_untracked_cache()) {
1862        case -1: /* keep: do nothing */
1863                break;
1864        case 0: /* false */
1865                remove_untracked_cache(istate);
1866                break;
1867        case 1: /* true */
1868                add_untracked_cache(istate);
1869                break;
1870        default: /* unknown value: do nothing */
1871                break;
1872        }
1873}
1874
1875static void tweak_split_index(struct index_state *istate)
1876{
1877        switch (git_config_get_split_index()) {
1878        case -1: /* unset: do nothing */
1879                break;
1880        case 0: /* false */
1881                remove_split_index(istate);
1882                break;
1883        case 1: /* true */
1884                add_split_index(istate);
1885                break;
1886        default: /* unknown value: do nothing */
1887                break;
1888        }
1889}
1890
1891static void post_read_index_from(struct index_state *istate)
1892{
1893        check_ce_order(istate);
1894        tweak_untracked_cache(istate);
1895        tweak_split_index(istate);
1896        tweak_fsmonitor(istate);
1897}
1898
1899static size_t estimate_cache_size_from_compressed(unsigned int entries)
1900{
1901        return entries * (sizeof(struct cache_entry) + CACHE_ENTRY_PATH_LENGTH);
1902}
1903
1904static size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1905{
1906        long per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1907
1908        /*
1909         * Account for potential alignment differences.
1910         */
1911        per_entry += align_padding_size(sizeof(struct cache_entry), -sizeof(struct ondisk_cache_entry));
1912        return ondisk_size + entries * per_entry;
1913}
1914
1915struct index_entry_offset
1916{
1917        /* starting byte offset into index file, count of index entries in this block */
1918        int offset, nr;
1919};
1920
1921struct index_entry_offset_table
1922{
1923        int nr;
1924        struct index_entry_offset entries[FLEX_ARRAY];
1925};
1926
1927static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset);
1928static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot);
1929
1930static size_t read_eoie_extension(const char *mmap, size_t mmap_size);
1931static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset);
1932
1933struct load_index_extensions
1934{
1935        pthread_t pthread;
1936        struct index_state *istate;
1937        const char *mmap;
1938        size_t mmap_size;
1939        unsigned long src_offset;
1940};
1941
1942static void *load_index_extensions(void *_data)
1943{
1944        struct load_index_extensions *p = _data;
1945        unsigned long src_offset = p->src_offset;
1946
1947        while (src_offset <= p->mmap_size - the_hash_algo->rawsz - 8) {
1948                /* After an array of active_nr index entries,
1949                 * there can be arbitrary number of extended
1950                 * sections, each of which is prefixed with
1951                 * extension name (4-byte) and section length
1952                 * in 4-byte network byte order.
1953                 */
1954                uint32_t extsize = get_be32(p->mmap + src_offset + 4);
1955                if (read_index_extension(p->istate,
1956                                         p->mmap + src_offset,
1957                                         p->mmap + src_offset + 8,
1958                                         extsize) < 0) {
1959                        munmap((void *)p->mmap, p->mmap_size);
1960                        die(_("index file corrupt"));
1961                }
1962                src_offset += 8;
1963                src_offset += extsize;
1964        }
1965
1966        return NULL;
1967}
1968
1969/*
1970 * A helper function that will load the specified range of cache entries
1971 * from the memory mapped file and add them to the given index.
1972 */
1973static unsigned long load_cache_entry_block(struct index_state *istate,
1974                        struct mem_pool *ce_mem_pool, int offset, int nr, const char *mmap,
1975                        unsigned long start_offset, const struct cache_entry *previous_ce)
1976{
1977        int i;
1978        unsigned long src_offset = start_offset;
1979
1980        for (i = offset; i < offset + nr; i++) {
1981                struct ondisk_cache_entry *disk_ce;
1982                struct cache_entry *ce;
1983                unsigned long consumed;
1984
1985                disk_ce = (struct ondisk_cache_entry *)(mmap + src_offset);
1986                ce = create_from_disk(ce_mem_pool, istate->version, disk_ce, &consumed, previous_ce);
1987                set_index_entry(istate, i, ce);
1988
1989                src_offset += consumed;
1990                previous_ce = ce;
1991        }
1992        return src_offset - start_offset;
1993}
1994
1995static unsigned long load_all_cache_entries(struct index_state *istate,
1996                        const char *mmap, size_t mmap_size, unsigned long src_offset)
1997{
1998        unsigned long consumed;
1999
2000        if (istate->version == 4) {
2001                mem_pool_init(&istate->ce_mem_pool,
2002                                estimate_cache_size_from_compressed(istate->cache_nr));
2003        } else {
2004                mem_pool_init(&istate->ce_mem_pool,
2005                                estimate_cache_size(mmap_size, istate->cache_nr));
2006        }
2007
2008        consumed = load_cache_entry_block(istate, istate->ce_mem_pool,
2009                                        0, istate->cache_nr, mmap, src_offset, NULL);
2010        return consumed;
2011}
2012
2013/*
2014 * Mostly randomly chosen maximum thread counts: we
2015 * cap the parallelism to online_cpus() threads, and we want
2016 * to have at least 10000 cache entries per thread for it to
2017 * be worth starting a thread.
2018 */
2019
2020#define THREAD_COST             (10000)
2021
2022struct load_cache_entries_thread_data
2023{
2024        pthread_t pthread;
2025        struct index_state *istate;
2026        struct mem_pool *ce_mem_pool;
2027        int offset;
2028        const char *mmap;
2029        struct index_entry_offset_table *ieot;
2030        int ieot_start;         /* starting index into the ieot array */
2031        int ieot_blocks;        /* count of ieot entries to process */
2032        unsigned long consumed; /* return # of bytes in index file processed */
2033};
2034
2035/*
2036 * A thread proc to run the load_cache_entries() computation
2037 * across multiple background threads.
2038 */
2039static void *load_cache_entries_thread(void *_data)
2040{
2041        struct load_cache_entries_thread_data *p = _data;
2042        int i;
2043
2044        /* iterate across all ieot blocks assigned to this thread */
2045        for (i = p->ieot_start; i < p->ieot_start + p->ieot_blocks; i++) {
2046                p->consumed += load_cache_entry_block(p->istate, p->ce_mem_pool,
2047                        p->offset, p->ieot->entries[i].nr, p->mmap, p->ieot->entries[i].offset, NULL);
2048                p->offset += p->ieot->entries[i].nr;
2049        }
2050        return NULL;
2051}
2052
2053static unsigned long load_cache_entries_threaded(struct index_state *istate, const char *mmap, size_t mmap_size,
2054                        unsigned long src_offset, int nr_threads, struct index_entry_offset_table *ieot)
2055{
2056        int i, offset, ieot_blocks, ieot_start, err;
2057        struct load_cache_entries_thread_data *data;
2058        unsigned long consumed = 0;
2059
2060        /* a little sanity checking */
2061        if (istate->name_hash_initialized)
2062                BUG("the name hash isn't thread safe");
2063
2064        mem_pool_init(&istate->ce_mem_pool, 0);
2065
2066        /* ensure we have no more threads than we have blocks to process */
2067        if (nr_threads > ieot->nr)
2068                nr_threads = ieot->nr;
2069        data = xcalloc(nr_threads, sizeof(*data));
2070
2071        offset = ieot_start = 0;
2072        ieot_blocks = DIV_ROUND_UP(ieot->nr, nr_threads);
2073        for (i = 0; i < nr_threads; i++) {
2074                struct load_cache_entries_thread_data *p = &data[i];
2075                int nr, j;
2076
2077                if (ieot_start + ieot_blocks > ieot->nr)
2078                        ieot_blocks = ieot->nr - ieot_start;
2079
2080                p->istate = istate;
2081                p->offset = offset;
2082                p->mmap = mmap;
2083                p->ieot = ieot;
2084                p->ieot_start = ieot_start;
2085                p->ieot_blocks = ieot_blocks;
2086
2087                /* create a mem_pool for each thread */
2088                nr = 0;
2089                for (j = p->ieot_start; j < p->ieot_start + p->ieot_blocks; j++)
2090                        nr += p->ieot->entries[j].nr;
2091                if (istate->version == 4) {
2092                        mem_pool_init(&p->ce_mem_pool,
2093                                estimate_cache_size_from_compressed(nr));
2094                } else {
2095                        mem_pool_init(&p->ce_mem_pool,
2096                                estimate_cache_size(mmap_size, nr));
2097                }
2098
2099                err = pthread_create(&p->pthread, NULL, load_cache_entries_thread, p);
2100                if (err)
2101                        die(_("unable to create load_cache_entries thread: %s"), strerror(err));
2102
2103                /* increment by the number of cache entries in the ieot block being processed */
2104                for (j = 0; j < ieot_blocks; j++)
2105                        offset += ieot->entries[ieot_start + j].nr;
2106                ieot_start += ieot_blocks;
2107        }
2108
2109        for (i = 0; i < nr_threads; i++) {
2110                struct load_cache_entries_thread_data *p = &data[i];
2111
2112                err = pthread_join(p->pthread, NULL);
2113                if (err)
2114                        die(_("unable to join load_cache_entries thread: %s"), strerror(err));
2115                mem_pool_combine(istate->ce_mem_pool, p->ce_mem_pool);
2116                consumed += p->consumed;
2117        }
2118
2119        free(data);
2120
2121        return consumed;
2122}
2123
2124/* remember to discard_cache() before reading a different cache! */
2125int do_read_index(struct index_state *istate, const char *path, int must_exist)
2126{
2127        int fd;
2128        struct stat st;
2129        unsigned long src_offset;
2130        const struct cache_header *hdr;
2131        const char *mmap;
2132        size_t mmap_size;
2133        struct load_index_extensions p;
2134        size_t extension_offset = 0;
2135        int nr_threads, cpus;
2136        struct index_entry_offset_table *ieot = NULL;
2137
2138        if (istate->initialized)
2139                return istate->cache_nr;
2140
2141        istate->timestamp.sec = 0;
2142        istate->timestamp.nsec = 0;
2143        fd = open(path, O_RDONLY);
2144        if (fd < 0) {
2145                if (!must_exist && errno == ENOENT)
2146                        return 0;
2147                die_errno("%s: index file open failed", path);
2148        }
2149
2150        if (fstat(fd, &st))
2151                die_errno("cannot stat the open index");
2152
2153        mmap_size = xsize_t(st.st_size);
2154        if (mmap_size < sizeof(struct cache_header) + the_hash_algo->rawsz)
2155                die("index file smaller than expected");
2156
2157        mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
2158        if (mmap == MAP_FAILED)
2159                die_errno("unable to map index file");
2160        close(fd);
2161
2162        hdr = (const struct cache_header *)mmap;
2163        if (verify_hdr(hdr, mmap_size) < 0)
2164                goto unmap;
2165
2166        hashcpy(istate->oid.hash, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz);
2167        istate->version = ntohl(hdr->hdr_version);
2168        istate->cache_nr = ntohl(hdr->hdr_entries);
2169        istate->cache_alloc = alloc_nr(istate->cache_nr);
2170        istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
2171        istate->initialized = 1;
2172
2173        p.istate = istate;
2174        p.mmap = mmap;
2175        p.mmap_size = mmap_size;
2176
2177        src_offset = sizeof(*hdr);
2178
2179        nr_threads = git_config_get_index_threads();
2180
2181        /* TODO: does creating more threads than cores help? */
2182        if (!nr_threads) {
2183                nr_threads = istate->cache_nr / THREAD_COST;
2184                cpus = online_cpus();
2185                if (nr_threads > cpus)
2186                        nr_threads = cpus;
2187        }
2188
2189        if (!HAVE_THREADS)
2190                nr_threads = 1;
2191
2192        if (nr_threads > 1) {
2193                extension_offset = read_eoie_extension(mmap, mmap_size);
2194                if (extension_offset) {
2195                        int err;
2196
2197                        p.src_offset = extension_offset;
2198                        err = pthread_create(&p.pthread, NULL, load_index_extensions, &p);
2199                        if (err)
2200                                die(_("unable to create load_index_extensions thread: %s"), strerror(err));
2201
2202                        nr_threads--;
2203                }
2204        }
2205
2206        /*
2207         * Locate and read the index entry offset table so that we can use it
2208         * to multi-thread the reading of the cache entries.
2209         */
2210        if (extension_offset && nr_threads > 1)
2211                ieot = read_ieot_extension(mmap, mmap_size, extension_offset);
2212
2213        if (ieot) {
2214                src_offset += load_cache_entries_threaded(istate, mmap, mmap_size, src_offset, nr_threads, ieot);
2215                free(ieot);
2216        } else {
2217                src_offset += load_all_cache_entries(istate, mmap, mmap_size, src_offset);
2218        }
2219
2220        istate->timestamp.sec = st.st_mtime;
2221        istate->timestamp.nsec = ST_MTIME_NSEC(st);
2222
2223        /* if we created a thread, join it otherwise load the extensions on the primary thread */
2224        if (extension_offset) {
2225                int ret = pthread_join(p.pthread, NULL);
2226                if (ret)
2227                        die(_("unable to join load_index_extensions thread: %s"), strerror(ret));
2228        } else {
2229                p.src_offset = src_offset;
2230                load_index_extensions(&p);
2231        }
2232        munmap((void *)mmap, mmap_size);
2233        return istate->cache_nr;
2234
2235unmap:
2236        munmap((void *)mmap, mmap_size);
2237        die("index file corrupt");
2238}
2239
2240/*
2241 * Signal that the shared index is used by updating its mtime.
2242 *
2243 * This way, shared index can be removed if they have not been used
2244 * for some time.
2245 */
2246static void freshen_shared_index(const char *shared_index, int warn)
2247{
2248        if (!check_and_freshen_file(shared_index, 1) && warn)
2249                warning("could not freshen shared index '%s'", shared_index);
2250}
2251
2252int read_index_from(struct index_state *istate, const char *path,
2253                    const char *gitdir)
2254{
2255        struct split_index *split_index;
2256        int ret;
2257        char *base_oid_hex;
2258        char *base_path;
2259
2260        /* istate->initialized covers both .git/index and .git/sharedindex.xxx */
2261        if (istate->initialized)
2262                return istate->cache_nr;
2263
2264        trace_performance_enter();
2265        ret = do_read_index(istate, path, 0);
2266        trace_performance_leave("read cache %s", path);
2267
2268        split_index = istate->split_index;
2269        if (!split_index || is_null_oid(&split_index->base_oid)) {
2270                post_read_index_from(istate);
2271                return ret;
2272        }
2273
2274        trace_performance_enter();
2275        if (split_index->base)
2276                discard_index(split_index->base);
2277        else
2278                split_index->base = xcalloc(1, sizeof(*split_index->base));
2279
2280        base_oid_hex = oid_to_hex(&split_index->base_oid);
2281        base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex);
2282        ret = do_read_index(split_index->base, base_path, 1);
2283        if (!oideq(&split_index->base_oid, &split_index->base->oid))
2284                die("broken index, expect %s in %s, got %s",
2285                    base_oid_hex, base_path,
2286                    oid_to_hex(&split_index->base->oid));
2287
2288        freshen_shared_index(base_path, 0);
2289        merge_base_index(istate);
2290        post_read_index_from(istate);
2291        trace_performance_leave("read cache %s", base_path);
2292        free(base_path);
2293        return ret;
2294}
2295
2296int is_index_unborn(struct index_state *istate)
2297{
2298        return (!istate->cache_nr && !istate->timestamp.sec);
2299}
2300
2301int discard_index(struct index_state *istate)
2302{
2303        /*
2304         * Cache entries in istate->cache[] should have been allocated
2305         * from the memory pool associated with this index, or from an
2306         * associated split_index. There is no need to free individual
2307         * cache entries. validate_cache_entries can detect when this
2308         * assertion does not hold.
2309         */
2310        validate_cache_entries(istate);
2311
2312        resolve_undo_clear_index(istate);
2313        istate->cache_nr = 0;
2314        istate->cache_changed = 0;
2315        istate->timestamp.sec = 0;
2316        istate->timestamp.nsec = 0;
2317        free_name_hash(istate);
2318        cache_tree_free(&(istate->cache_tree));
2319        istate->initialized = 0;
2320        FREE_AND_NULL(istate->cache);
2321        istate->cache_alloc = 0;
2322        discard_split_index(istate);
2323        free_untracked_cache(istate->untracked);
2324        istate->untracked = NULL;
2325
2326        if (istate->ce_mem_pool) {
2327                mem_pool_discard(istate->ce_mem_pool, should_validate_cache_entries());
2328                istate->ce_mem_pool = NULL;
2329        }
2330
2331        return 0;
2332}
2333
2334/*
2335 * Validate the cache entries of this index.
2336 * All cache entries associated with this index
2337 * should have been allocated by the memory pool
2338 * associated with this index, or by a referenced
2339 * split index.
2340 */
2341void validate_cache_entries(const struct index_state *istate)
2342{
2343        int i;
2344
2345        if (!should_validate_cache_entries() ||!istate || !istate->initialized)
2346                return;
2347
2348        for (i = 0; i < istate->cache_nr; i++) {
2349                if (!istate) {
2350                        die("internal error: cache entry is not allocated from expected memory pool");
2351                } else if (!istate->ce_mem_pool ||
2352                        !mem_pool_contains(istate->ce_mem_pool, istate->cache[i])) {
2353                        if (!istate->split_index ||
2354                                !istate->split_index->base ||
2355                                !istate->split_index->base->ce_mem_pool ||
2356                                !mem_pool_contains(istate->split_index->base->ce_mem_pool, istate->cache[i])) {
2357                                die("internal error: cache entry is not allocated from expected memory pool");
2358                        }
2359                }
2360        }
2361
2362        if (istate->split_index)
2363                validate_cache_entries(istate->split_index->base);
2364}
2365
2366int unmerged_index(const struct index_state *istate)
2367{
2368        int i;
2369        for (i = 0; i < istate->cache_nr; i++) {
2370                if (ce_stage(istate->cache[i]))
2371                        return 1;
2372        }
2373        return 0;
2374}
2375
2376int index_has_changes(struct index_state *istate,
2377                      struct tree *tree,
2378                      struct strbuf *sb)
2379{
2380        struct object_id cmp;
2381        int i;
2382
2383        if (istate != &the_index) {
2384                BUG("index_has_changes cannot yet accept istate != &the_index; do_diff_cache needs updating first.");
2385        }
2386        if (tree)
2387                cmp = tree->object.oid;
2388        if (tree || !get_oid_tree("HEAD", &cmp)) {
2389                struct diff_options opt;
2390
2391                repo_diff_setup(the_repository, &opt);
2392                opt.flags.exit_with_status = 1;
2393                if (!sb)
2394                        opt.flags.quick = 1;
2395                do_diff_cache(&cmp, &opt);
2396                diffcore_std(&opt);
2397                for (i = 0; sb && i < diff_queued_diff.nr; i++) {
2398                        if (i)
2399                                strbuf_addch(sb, ' ');
2400                        strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
2401                }
2402                diff_flush(&opt);
2403                return opt.flags.has_changes != 0;
2404        } else {
2405                for (i = 0; sb && i < istate->cache_nr; i++) {
2406                        if (i)
2407                                strbuf_addch(sb, ' ');
2408                        strbuf_addstr(sb, istate->cache[i]->name);
2409                }
2410                return !!istate->cache_nr;
2411        }
2412}
2413
2414#define WRITE_BUFFER_SIZE 8192
2415static unsigned char write_buffer[WRITE_BUFFER_SIZE];
2416static unsigned long write_buffer_len;
2417
2418static int ce_write_flush(git_hash_ctx *context, int fd)
2419{
2420        unsigned int buffered = write_buffer_len;
2421        if (buffered) {
2422                the_hash_algo->update_fn(context, write_buffer, buffered);
2423                if (write_in_full(fd, write_buffer, buffered) < 0)
2424                        return -1;
2425                write_buffer_len = 0;
2426        }
2427        return 0;
2428}
2429
2430static int ce_write(git_hash_ctx *context, int fd, void *data, unsigned int len)
2431{
2432        while (len) {
2433                unsigned int buffered = write_buffer_len;
2434                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
2435                if (partial > len)
2436                        partial = len;
2437                memcpy(write_buffer + buffered, data, partial);
2438                buffered += partial;
2439                if (buffered == WRITE_BUFFER_SIZE) {
2440                        write_buffer_len = buffered;
2441                        if (ce_write_flush(context, fd))
2442                                return -1;
2443                        buffered = 0;
2444                }
2445                write_buffer_len = buffered;
2446                len -= partial;
2447                data = (char *) data + partial;
2448        }
2449        return 0;
2450}
2451
2452static int write_index_ext_header(git_hash_ctx *context, git_hash_ctx *eoie_context,
2453                                  int fd, unsigned int ext, unsigned int sz)
2454{
2455        ext = htonl(ext);
2456        sz = htonl(sz);
2457        if (eoie_context) {
2458                the_hash_algo->update_fn(eoie_context, &ext, 4);
2459                the_hash_algo->update_fn(eoie_context, &sz, 4);
2460        }
2461        return ((ce_write(context, fd, &ext, 4) < 0) ||
2462                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
2463}
2464
2465static int ce_flush(git_hash_ctx *context, int fd, unsigned char *hash)
2466{
2467        unsigned int left = write_buffer_len;
2468
2469        if (left) {
2470                write_buffer_len = 0;
2471                the_hash_algo->update_fn(context, write_buffer, left);
2472        }
2473
2474        /* Flush first if not enough space for hash signature */
2475        if (left + the_hash_algo->rawsz > WRITE_BUFFER_SIZE) {
2476                if (write_in_full(fd, write_buffer, left) < 0)
2477                        return -1;
2478                left = 0;
2479        }
2480
2481        /* Append the hash signature at the end */
2482        the_hash_algo->final_fn(write_buffer + left, context);
2483        hashcpy(hash, write_buffer + left);
2484        left += the_hash_algo->rawsz;
2485        return (write_in_full(fd, write_buffer, left) < 0) ? -1 : 0;
2486}
2487
2488static void ce_smudge_racily_clean_entry(struct index_state *istate,
2489                                         struct cache_entry *ce)
2490{
2491        /*
2492         * The only thing we care about in this function is to smudge the
2493         * falsely clean entry due to touch-update-touch race, so we leave
2494         * everything else as they are.  We are called for entries whose
2495         * ce_stat_data.sd_mtime match the index file mtime.
2496         *
2497         * Note that this actually does not do much for gitlinks, for
2498         * which ce_match_stat_basic() always goes to the actual
2499         * contents.  The caller checks with is_racy_timestamp() which
2500         * always says "no" for gitlinks, so we are not called for them ;-)
2501         */
2502        struct stat st;
2503
2504        if (lstat(ce->name, &st) < 0)
2505                return;
2506        if (ce_match_stat_basic(ce, &st))
2507                return;
2508        if (ce_modified_check_fs(istate, ce, &st)) {
2509                /* This is "racily clean"; smudge it.  Note that this
2510                 * is a tricky code.  At first glance, it may appear
2511                 * that it can break with this sequence:
2512                 *
2513                 * $ echo xyzzy >frotz
2514                 * $ git-update-index --add frotz
2515                 * $ : >frotz
2516                 * $ sleep 3
2517                 * $ echo filfre >nitfol
2518                 * $ git-update-index --add nitfol
2519                 *
2520                 * but it does not.  When the second update-index runs,
2521                 * it notices that the entry "frotz" has the same timestamp
2522                 * as index, and if we were to smudge it by resetting its
2523                 * size to zero here, then the object name recorded
2524                 * in index is the 6-byte file but the cached stat information
2525                 * becomes zero --- which would then match what we would
2526                 * obtain from the filesystem next time we stat("frotz").
2527                 *
2528                 * However, the second update-index, before calling
2529                 * this function, notices that the cached size is 6
2530                 * bytes and what is on the filesystem is an empty
2531                 * file, and never calls us, so the cached size information
2532                 * for "frotz" stays 6 which does not match the filesystem.
2533                 */
2534                ce->ce_stat_data.sd_size = 0;
2535        }
2536}
2537
2538/* Copy miscellaneous fields but not the name */
2539static void copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
2540                                       struct cache_entry *ce)
2541{
2542        short flags;
2543
2544        ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec);
2545        ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec);
2546        ondisk->ctime.nsec = htonl(ce->ce_stat_data.sd_ctime.nsec);
2547        ondisk->mtime.nsec = htonl(ce->ce_stat_data.sd_mtime.nsec);
2548        ondisk->dev  = htonl(ce->ce_stat_data.sd_dev);
2549        ondisk->ino  = htonl(ce->ce_stat_data.sd_ino);
2550        ondisk->mode = htonl(ce->ce_mode);
2551        ondisk->uid  = htonl(ce->ce_stat_data.sd_uid);
2552        ondisk->gid  = htonl(ce->ce_stat_data.sd_gid);
2553        ondisk->size = htonl(ce->ce_stat_data.sd_size);
2554        hashcpy(ondisk->sha1, ce->oid.hash);
2555
2556        flags = ce->ce_flags & ~CE_NAMEMASK;
2557        flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
2558        ondisk->flags = htons(flags);
2559        if (ce->ce_flags & CE_EXTENDED) {
2560                struct ondisk_cache_entry_extended *ondisk2;
2561                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
2562                ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
2563        }
2564}
2565
2566static int ce_write_entry(git_hash_ctx *c, int fd, struct cache_entry *ce,
2567                          struct strbuf *previous_name, struct ondisk_cache_entry *ondisk)
2568{
2569        int size;
2570        int result;
2571        unsigned int saved_namelen;
2572        int stripped_name = 0;
2573        static unsigned char padding[8] = { 0x00 };
2574
2575        if (ce->ce_flags & CE_STRIP_NAME) {
2576                saved_namelen = ce_namelen(ce);
2577                ce->ce_namelen = 0;
2578                stripped_name = 1;
2579        }
2580
2581        if (ce->ce_flags & CE_EXTENDED)
2582                size = offsetof(struct ondisk_cache_entry_extended, name);
2583        else
2584                size = offsetof(struct ondisk_cache_entry, name);
2585
2586        if (!previous_name) {
2587                int len = ce_namelen(ce);
2588                copy_cache_entry_to_ondisk(ondisk, ce);
2589                result = ce_write(c, fd, ondisk, size);
2590                if (!result)
2591                        result = ce_write(c, fd, ce->name, len);
2592                if (!result)
2593                        result = ce_write(c, fd, padding, align_padding_size(size, len));
2594        } else {
2595                int common, to_remove, prefix_size;
2596                unsigned char to_remove_vi[16];
2597                for (common = 0;
2598                     (ce->name[common] &&
2599                      common < previous_name->len &&
2600                      ce->name[common] == previous_name->buf[common]);
2601                     common++)
2602                        ; /* still matching */
2603                to_remove = previous_name->len - common;
2604                prefix_size = encode_varint(to_remove, to_remove_vi);
2605
2606                copy_cache_entry_to_ondisk(ondisk, ce);
2607                result = ce_write(c, fd, ondisk, size);
2608                if (!result)
2609                        result = ce_write(c, fd, to_remove_vi, prefix_size);
2610                if (!result)
2611                        result = ce_write(c, fd, ce->name + common, ce_namelen(ce) - common);
2612                if (!result)
2613                        result = ce_write(c, fd, padding, 1);
2614
2615                strbuf_splice(previous_name, common, to_remove,
2616                              ce->name + common, ce_namelen(ce) - common);
2617        }
2618        if (stripped_name) {
2619                ce->ce_namelen = saved_namelen;
2620                ce->ce_flags &= ~CE_STRIP_NAME;
2621        }
2622
2623        return result;
2624}
2625
2626/*
2627 * This function verifies if index_state has the correct sha1 of the
2628 * index file.  Don't die if we have any other failure, just return 0.
2629 */
2630static int verify_index_from(const struct index_state *istate, const char *path)
2631{
2632        int fd;
2633        ssize_t n;
2634        struct stat st;
2635        unsigned char hash[GIT_MAX_RAWSZ];
2636
2637        if (!istate->initialized)
2638                return 0;
2639
2640        fd = open(path, O_RDONLY);
2641        if (fd < 0)
2642                return 0;
2643
2644        if (fstat(fd, &st))
2645                goto out;
2646
2647        if (st.st_size < sizeof(struct cache_header) + the_hash_algo->rawsz)
2648                goto out;
2649
2650        n = pread_in_full(fd, hash, the_hash_algo->rawsz, st.st_size - the_hash_algo->rawsz);
2651        if (n != the_hash_algo->rawsz)
2652                goto out;
2653
2654        if (!hasheq(istate->oid.hash, hash))
2655                goto out;
2656
2657        close(fd);
2658        return 1;
2659
2660out:
2661        close(fd);
2662        return 0;
2663}
2664
2665static int verify_index(const struct index_state *istate)
2666{
2667        return verify_index_from(istate, get_index_file());
2668}
2669
2670static int has_racy_timestamp(struct index_state *istate)
2671{
2672        int entries = istate->cache_nr;
2673        int i;
2674
2675        for (i = 0; i < entries; i++) {
2676                struct cache_entry *ce = istate->cache[i];
2677                if (is_racy_timestamp(istate, ce))
2678                        return 1;
2679        }
2680        return 0;
2681}
2682
2683void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
2684{
2685        if ((istate->cache_changed || has_racy_timestamp(istate)) &&
2686            verify_index(istate))
2687                write_locked_index(istate, lockfile, COMMIT_LOCK);
2688        else
2689                rollback_lock_file(lockfile);
2690}
2691
2692/*
2693 * On success, `tempfile` is closed. If it is the temporary file
2694 * of a `struct lock_file`, we will therefore effectively perform
2695 * a 'close_lock_file_gently()`. Since that is an implementation
2696 * detail of lockfiles, callers of `do_write_index()` should not
2697 * rely on it.
2698 */
2699static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
2700                          int strip_extensions)
2701{
2702        uint64_t start = getnanotime();
2703        int newfd = tempfile->fd;
2704        git_hash_ctx c, eoie_c;
2705        struct cache_header hdr;
2706        int i, err = 0, removed, extended, hdr_version;
2707        struct cache_entry **cache = istate->cache;
2708        int entries = istate->cache_nr;
2709        struct stat st;
2710        struct ondisk_cache_entry_extended ondisk;
2711        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
2712        int drop_cache_tree = istate->drop_cache_tree;
2713        off_t offset;
2714        int ieot_entries = 1;
2715        struct index_entry_offset_table *ieot = NULL;
2716        int nr, nr_threads;
2717
2718        for (i = removed = extended = 0; i < entries; i++) {
2719                if (cache[i]->ce_flags & CE_REMOVE)
2720                        removed++;
2721
2722                /* reduce extended entries if possible */
2723                cache[i]->ce_flags &= ~CE_EXTENDED;
2724                if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) {
2725                        extended++;
2726                        cache[i]->ce_flags |= CE_EXTENDED;
2727                }
2728        }
2729
2730        if (!istate->version) {
2731                istate->version = get_index_format_default();
2732                if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0))
2733                        init_split_index(istate);
2734        }
2735
2736        /* demote version 3 to version 2 when the latter suffices */
2737        if (istate->version == 3 || istate->version == 2)
2738                istate->version = extended ? 3 : 2;
2739
2740        hdr_version = istate->version;
2741
2742        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
2743        hdr.hdr_version = htonl(hdr_version);
2744        hdr.hdr_entries = htonl(entries - removed);
2745
2746        the_hash_algo->init_fn(&c);
2747        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
2748                return -1;
2749
2750        if (HAVE_THREADS)
2751                nr_threads = git_config_get_index_threads();
2752        else
2753                nr_threads = 1;
2754
2755        if (nr_threads != 1) {
2756                int ieot_blocks, cpus;
2757
2758                /*
2759                 * ensure default number of ieot blocks maps evenly to the
2760                 * default number of threads that will process them leaving
2761                 * room for the thread to load the index extensions.
2762                 */
2763                if (!nr_threads) {
2764                        ieot_blocks = istate->cache_nr / THREAD_COST;
2765                        cpus = online_cpus();
2766                        if (ieot_blocks > cpus - 1)
2767                                ieot_blocks = cpus - 1;
2768                } else {
2769                        ieot_blocks = nr_threads;
2770                        if (ieot_blocks > istate->cache_nr)
2771                                ieot_blocks = istate->cache_nr;
2772                }
2773
2774                /*
2775                 * no reason to write out the IEOT extension if we don't
2776                 * have enough blocks to utilize multi-threading
2777                 */
2778                if (ieot_blocks > 1) {
2779                        ieot = xcalloc(1, sizeof(struct index_entry_offset_table)
2780                                + (ieot_blocks * sizeof(struct index_entry_offset)));
2781                        ieot_entries = DIV_ROUND_UP(entries, ieot_blocks);
2782                }
2783        }
2784
2785        offset = lseek(newfd, 0, SEEK_CUR);
2786        if (offset < 0) {
2787                free(ieot);
2788                return -1;
2789        }
2790        offset += write_buffer_len;
2791        nr = 0;
2792        previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
2793
2794        for (i = 0; i < entries; i++) {
2795                struct cache_entry *ce = cache[i];
2796                if (ce->ce_flags & CE_REMOVE)
2797                        continue;
2798                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
2799                        ce_smudge_racily_clean_entry(istate, ce);
2800                if (is_null_oid(&ce->oid)) {
2801                        static const char msg[] = "cache entry has null sha1: %s";
2802                        static int allow = -1;
2803
2804                        if (allow < 0)
2805                                allow = git_env_bool("GIT_ALLOW_NULL_SHA1", 0);
2806                        if (allow)
2807                                warning(msg, ce->name);
2808                        else
2809                                err = error(msg, ce->name);
2810
2811                        drop_cache_tree = 1;
2812                }
2813                if (ieot && i && (i % ieot_entries == 0)) {
2814                        ieot->entries[ieot->nr].nr = nr;
2815                        ieot->entries[ieot->nr].offset = offset;
2816                        ieot->nr++;
2817                        /*
2818                         * If we have a V4 index, set the first byte to an invalid
2819                         * character to ensure there is nothing common with the previous
2820                         * entry
2821                         */
2822                        if (previous_name)
2823                                previous_name->buf[0] = 0;
2824                        nr = 0;
2825                        offset = lseek(newfd, 0, SEEK_CUR);
2826                        if (offset < 0) {
2827                                free(ieot);
2828                                return -1;
2829                        }
2830                        offset += write_buffer_len;
2831                }
2832                if (ce_write_entry(&c, newfd, ce, previous_name, (struct ondisk_cache_entry *)&ondisk) < 0)
2833                        err = -1;
2834
2835                if (err)
2836                        break;
2837                nr++;
2838        }
2839        if (ieot && nr) {
2840                ieot->entries[ieot->nr].nr = nr;
2841                ieot->entries[ieot->nr].offset = offset;
2842                ieot->nr++;
2843        }
2844        strbuf_release(&previous_name_buf);
2845
2846        if (err) {
2847                free(ieot);
2848                return err;
2849        }
2850
2851        /* Write extension data here */
2852        offset = lseek(newfd, 0, SEEK_CUR);
2853        if (offset < 0) {
2854                free(ieot);
2855                return -1;
2856        }
2857        offset += write_buffer_len;
2858        the_hash_algo->init_fn(&eoie_c);
2859
2860        /*
2861         * Lets write out CACHE_EXT_INDEXENTRYOFFSETTABLE first so that we
2862         * can minimize the number of extensions we have to scan through to
2863         * find it during load.  Write it out regardless of the
2864         * strip_extensions parameter as we need it when loading the shared
2865         * index.
2866         */
2867        if (ieot) {
2868                struct strbuf sb = STRBUF_INIT;
2869
2870                write_ieot_extension(&sb, ieot);
2871                err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_INDEXENTRYOFFSETTABLE, sb.len) < 0
2872                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2873                strbuf_release(&sb);
2874                free(ieot);
2875                if (err)
2876                        return -1;
2877        }
2878
2879        if (!strip_extensions && istate->split_index) {
2880                struct strbuf sb = STRBUF_INIT;
2881
2882                err = write_link_extension(&sb, istate) < 0 ||
2883                        write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_LINK,
2884                                               sb.len) < 0 ||
2885                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2886                strbuf_release(&sb);
2887                if (err)
2888                        return -1;
2889        }
2890        if (!strip_extensions && !drop_cache_tree && istate->cache_tree) {
2891                struct strbuf sb = STRBUF_INIT;
2892
2893                cache_tree_write(&sb, istate->cache_tree);
2894                err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_TREE, sb.len) < 0
2895                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2896                strbuf_release(&sb);
2897                if (err)
2898                        return -1;
2899        }
2900        if (!strip_extensions && istate->resolve_undo) {
2901                struct strbuf sb = STRBUF_INIT;
2902
2903                resolve_undo_write(&sb, istate->resolve_undo);
2904                err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_RESOLVE_UNDO,
2905                                             sb.len) < 0
2906                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2907                strbuf_release(&sb);
2908                if (err)
2909                        return -1;
2910        }
2911        if (!strip_extensions && istate->untracked) {
2912                struct strbuf sb = STRBUF_INIT;
2913
2914                write_untracked_extension(&sb, istate->untracked);
2915                err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_UNTRACKED,
2916                                             sb.len) < 0 ||
2917                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2918                strbuf_release(&sb);
2919                if (err)
2920                        return -1;
2921        }
2922        if (!strip_extensions && istate->fsmonitor_last_update) {
2923                struct strbuf sb = STRBUF_INIT;
2924
2925                write_fsmonitor_extension(&sb, istate);
2926                err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_FSMONITOR, sb.len) < 0
2927                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2928                strbuf_release(&sb);
2929                if (err)
2930                        return -1;
2931        }
2932
2933        /*
2934         * CACHE_EXT_ENDOFINDEXENTRIES must be written as the last entry before the SHA1
2935         * so that it can be found and processed before all the index entries are
2936         * read.  Write it out regardless of the strip_extensions parameter as we need it
2937         * when loading the shared index.
2938         */
2939        if (offset) {
2940                struct strbuf sb = STRBUF_INIT;
2941
2942                write_eoie_extension(&sb, &eoie_c, offset);
2943                err = write_index_ext_header(&c, NULL, newfd, CACHE_EXT_ENDOFINDEXENTRIES, sb.len) < 0
2944                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2945                strbuf_release(&sb);
2946                if (err)
2947                        return -1;
2948        }
2949
2950        if (ce_flush(&c, newfd, istate->oid.hash))
2951                return -1;
2952        if (close_tempfile_gently(tempfile)) {
2953                error(_("could not close '%s'"), tempfile->filename.buf);
2954                return -1;
2955        }
2956        if (stat(tempfile->filename.buf, &st))
2957                return -1;
2958        istate->timestamp.sec = (unsigned int)st.st_mtime;
2959        istate->timestamp.nsec = ST_MTIME_NSEC(st);
2960        trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed);
2961        return 0;
2962}
2963
2964void set_alternate_index_output(const char *name)
2965{
2966        alternate_index_output = name;
2967}
2968
2969static int commit_locked_index(struct lock_file *lk)
2970{
2971        if (alternate_index_output)
2972                return commit_lock_file_to(lk, alternate_index_output);
2973        else
2974                return commit_lock_file(lk);
2975}
2976
2977static int do_write_locked_index(struct index_state *istate, struct lock_file *lock,
2978                                 unsigned flags)
2979{
2980        int ret = do_write_index(istate, lock->tempfile, 0);
2981        if (ret)
2982                return ret;
2983        if (flags & COMMIT_LOCK)
2984                return commit_locked_index(lock);
2985        return close_lock_file_gently(lock);
2986}
2987
2988static int write_split_index(struct index_state *istate,
2989                             struct lock_file *lock,
2990                             unsigned flags)
2991{
2992        int ret;
2993        prepare_to_write_split_index(istate);
2994        ret = do_write_locked_index(istate, lock, flags);
2995        finish_writing_split_index(istate);
2996        return ret;
2997}
2998
2999static const char *shared_index_expire = "2.weeks.ago";
3000
3001static unsigned long get_shared_index_expire_date(void)
3002{
3003        static unsigned long shared_index_expire_date;
3004        static int shared_index_expire_date_prepared;
3005
3006        if (!shared_index_expire_date_prepared) {
3007                git_config_get_expiry("splitindex.sharedindexexpire",
3008                                      &shared_index_expire);
3009                shared_index_expire_date = approxidate(shared_index_expire);
3010                shared_index_expire_date_prepared = 1;
3011        }
3012
3013        return shared_index_expire_date;
3014}
3015
3016static int should_delete_shared_index(const char *shared_index_path)
3017{
3018        struct stat st;
3019        unsigned long expiration;
3020
3021        /* Check timestamp */
3022        expiration = get_shared_index_expire_date();
3023        if (!expiration)
3024                return 0;
3025        if (stat(shared_index_path, &st))
3026                return error_errno(_("could not stat '%s'"), shared_index_path);
3027        if (st.st_mtime > expiration)
3028                return 0;
3029
3030        return 1;
3031}
3032
3033static int clean_shared_index_files(const char *current_hex)
3034{
3035        struct dirent *de;
3036        DIR *dir = opendir(get_git_dir());
3037
3038        if (!dir)
3039                return error_errno(_("unable to open git dir: %s"), get_git_dir());
3040
3041        while ((de = readdir(dir)) != NULL) {
3042                const char *sha1_hex;
3043                const char *shared_index_path;
3044                if (!skip_prefix(de->d_name, "sharedindex.", &sha1_hex))
3045                        continue;
3046                if (!strcmp(sha1_hex, current_hex))
3047                        continue;
3048                shared_index_path = git_path("%s", de->d_name);
3049                if (should_delete_shared_index(shared_index_path) > 0 &&
3050                    unlink(shared_index_path))
3051                        warning_errno(_("unable to unlink: %s"), shared_index_path);
3052        }
3053        closedir(dir);
3054
3055        return 0;
3056}
3057
3058static int write_shared_index(struct index_state *istate,
3059                              struct tempfile **temp)
3060{
3061        struct split_index *si = istate->split_index;
3062        int ret;
3063
3064        move_cache_to_base_index(istate);
3065        ret = do_write_index(si->base, *temp, 1);
3066        if (ret)
3067                return ret;
3068        ret = adjust_shared_perm(get_tempfile_path(*temp));
3069        if (ret) {
3070                error("cannot fix permission bits on %s", get_tempfile_path(*temp));
3071                return ret;
3072        }
3073        ret = rename_tempfile(temp,
3074                              git_path("sharedindex.%s", oid_to_hex(&si->base->oid)));
3075        if (!ret) {
3076                oidcpy(&si->base_oid, &si->base->oid);
3077                clean_shared_index_files(oid_to_hex(&si->base->oid));
3078        }
3079
3080        return ret;
3081}
3082
3083static const int default_max_percent_split_change = 20;
3084
3085static int too_many_not_shared_entries(struct index_state *istate)
3086{
3087        int i, not_shared = 0;
3088        int max_split = git_config_get_max_percent_split_change();
3089
3090        switch (max_split) {
3091        case -1:
3092                /* not or badly configured: use the default value */
3093                max_split = default_max_percent_split_change;
3094                break;
3095        case 0:
3096                return 1; /* 0% means always write a new shared index */
3097        case 100:
3098                return 0; /* 100% means never write a new shared index */
3099        default:
3100                break; /* just use the configured value */
3101        }
3102
3103        /* Count not shared entries */
3104        for (i = 0; i < istate->cache_nr; i++) {
3105                struct cache_entry *ce = istate->cache[i];
3106                if (!ce->index)
3107                        not_shared++;
3108        }
3109
3110        return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100;
3111}
3112
3113int write_locked_index(struct index_state *istate, struct lock_file *lock,
3114                       unsigned flags)
3115{
3116        int new_shared_index, ret;
3117        struct split_index *si = istate->split_index;
3118
3119        if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0))
3120                cache_tree_verify(istate);
3121
3122        if ((flags & SKIP_IF_UNCHANGED) && !istate->cache_changed) {
3123                if (flags & COMMIT_LOCK)
3124                        rollback_lock_file(lock);
3125                return 0;
3126        }
3127
3128        if (istate->fsmonitor_last_update)
3129                fill_fsmonitor_bitmap(istate);
3130
3131        if (!si || alternate_index_output ||
3132            (istate->cache_changed & ~EXTMASK)) {
3133                if (si)
3134                        oidclr(&si->base_oid);
3135                ret = do_write_locked_index(istate, lock, flags);
3136                goto out;
3137        }
3138
3139        if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) {
3140                int v = si->base_oid.hash[0];
3141                if ((v & 15) < 6)
3142                        istate->cache_changed |= SPLIT_INDEX_ORDERED;
3143        }
3144        if (too_many_not_shared_entries(istate))
3145                istate->cache_changed |= SPLIT_INDEX_ORDERED;
3146
3147        new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED;
3148
3149        if (new_shared_index) {
3150                struct tempfile *temp;
3151                int saved_errno;
3152
3153                temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
3154                if (!temp) {
3155                        oidclr(&si->base_oid);
3156                        ret = do_write_locked_index(istate, lock, flags);
3157                        goto out;
3158                }
3159                ret = write_shared_index(istate, &temp);
3160
3161                saved_errno = errno;
3162                if (is_tempfile_active(temp))
3163                        delete_tempfile(&temp);
3164                errno = saved_errno;
3165
3166                if (ret)
3167                        goto out;
3168        }
3169
3170        ret = write_split_index(istate, lock, flags);
3171
3172        /* Freshen the shared index only if the split-index was written */
3173        if (!ret && !new_shared_index) {
3174                const char *shared_index = git_path("sharedindex.%s",
3175                                                    oid_to_hex(&si->base_oid));
3176                freshen_shared_index(shared_index, 1);
3177        }
3178
3179out:
3180        if (flags & COMMIT_LOCK)
3181                rollback_lock_file(lock);
3182        return ret;
3183}
3184
3185/*
3186 * Read the index file that is potentially unmerged into given
3187 * index_state, dropping any unmerged entries to stage #0 (potentially
3188 * resulting in a path appearing as both a file and a directory in the
3189 * index; the caller is responsible to clear out the extra entries
3190 * before writing the index to a tree).  Returns true if the index is
3191 * unmerged.  Callers who want to refuse to work from an unmerged
3192 * state can call this and check its return value, instead of calling
3193 * read_cache().
3194 */
3195int read_index_unmerged(struct index_state *istate)
3196{
3197        int i;
3198        int unmerged = 0;
3199
3200        read_index(istate);
3201        for (i = 0; i < istate->cache_nr; i++) {
3202                struct cache_entry *ce = istate->cache[i];
3203                struct cache_entry *new_ce;
3204                int len;
3205
3206                if (!ce_stage(ce))
3207                        continue;
3208                unmerged = 1;
3209                len = ce_namelen(ce);
3210                new_ce = make_empty_cache_entry(istate, len);
3211                memcpy(new_ce->name, ce->name, len);
3212                new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED;
3213                new_ce->ce_namelen = len;
3214                new_ce->ce_mode = ce->ce_mode;
3215                if (add_index_entry(istate, new_ce, ADD_CACHE_SKIP_DFCHECK))
3216                        return error("%s: cannot drop to stage #0",
3217                                     new_ce->name);
3218        }
3219        return unmerged;
3220}
3221
3222/*
3223 * Returns 1 if the path is an "other" path with respect to
3224 * the index; that is, the path is not mentioned in the index at all,
3225 * either as a file, a directory with some files in the index,
3226 * or as an unmerged entry.
3227 *
3228 * We helpfully remove a trailing "/" from directories so that
3229 * the output of read_directory can be used as-is.
3230 */
3231int index_name_is_other(const struct index_state *istate, const char *name,
3232                int namelen)
3233{
3234        int pos;
3235        if (namelen && name[namelen - 1] == '/')
3236                namelen--;
3237        pos = index_name_pos(istate, name, namelen);
3238        if (0 <= pos)
3239                return 0;       /* exact match */
3240        pos = -pos - 1;
3241        if (pos < istate->cache_nr) {
3242                struct cache_entry *ce = istate->cache[pos];
3243                if (ce_namelen(ce) == namelen &&
3244                    !memcmp(ce->name, name, namelen))
3245                        return 0; /* Yup, this one exists unmerged */
3246        }
3247        return 1;
3248}
3249
3250void *read_blob_data_from_index(const struct index_state *istate,
3251                                const char *path, unsigned long *size)
3252{
3253        int pos, len;
3254        unsigned long sz;
3255        enum object_type type;
3256        void *data;
3257
3258        len = strlen(path);
3259        pos = index_name_pos(istate, path, len);
3260        if (pos < 0) {
3261                /*
3262                 * We might be in the middle of a merge, in which
3263                 * case we would read stage #2 (ours).
3264                 */
3265                int i;
3266                for (i = -pos - 1;
3267                     (pos < 0 && i < istate->cache_nr &&
3268                      !strcmp(istate->cache[i]->name, path));
3269                     i++)
3270                        if (ce_stage(istate->cache[i]) == 2)
3271                                pos = i;
3272        }
3273        if (pos < 0)
3274                return NULL;
3275        data = read_object_file(&istate->cache[pos]->oid, &type, &sz);
3276        if (!data || type != OBJ_BLOB) {
3277                free(data);
3278                return NULL;
3279        }
3280        if (size)
3281                *size = sz;
3282        return data;
3283}
3284
3285void stat_validity_clear(struct stat_validity *sv)
3286{
3287        FREE_AND_NULL(sv->sd);
3288}
3289
3290int stat_validity_check(struct stat_validity *sv, const char *path)
3291{
3292        struct stat st;
3293
3294        if (stat(path, &st) < 0)
3295                return sv->sd == NULL;
3296        if (!sv->sd)
3297                return 0;
3298        return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
3299}
3300
3301void stat_validity_update(struct stat_validity *sv, int fd)
3302{
3303        struct stat st;
3304
3305        if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
3306                stat_validity_clear(sv);
3307        else {
3308                if (!sv->sd)
3309                        sv->sd = xcalloc(1, sizeof(struct stat_data));
3310                fill_stat_data(sv->sd, &st);
3311        }
3312}
3313
3314void move_index_extensions(struct index_state *dst, struct index_state *src)
3315{
3316        dst->untracked = src->untracked;
3317        src->untracked = NULL;
3318        dst->cache_tree = src->cache_tree;
3319        src->cache_tree = NULL;
3320}
3321
3322struct cache_entry *dup_cache_entry(const struct cache_entry *ce,
3323                                    struct index_state *istate)
3324{
3325        unsigned int size = ce_size(ce);
3326        int mem_pool_allocated;
3327        struct cache_entry *new_entry = make_empty_cache_entry(istate, ce_namelen(ce));
3328        mem_pool_allocated = new_entry->mem_pool_allocated;
3329
3330        memcpy(new_entry, ce, size);
3331        new_entry->mem_pool_allocated = mem_pool_allocated;
3332        return new_entry;
3333}
3334
3335void discard_cache_entry(struct cache_entry *ce)
3336{
3337        if (ce && should_validate_cache_entries())
3338                memset(ce, 0xCD, cache_entry_size(ce->ce_namelen));
3339
3340        if (ce && ce->mem_pool_allocated)
3341                return;
3342
3343        free(ce);
3344}
3345
3346int should_validate_cache_entries(void)
3347{
3348        static int validate_index_cache_entries = -1;
3349
3350        if (validate_index_cache_entries < 0) {
3351                if (getenv("GIT_TEST_VALIDATE_INDEX_CACHE_ENTRIES"))
3352                        validate_index_cache_entries = 1;
3353                else
3354                        validate_index_cache_entries = 0;
3355        }
3356
3357        return validate_index_cache_entries;
3358}
3359
3360#define EOIE_SIZE (4 + GIT_SHA1_RAWSZ) /* <4-byte offset> + <20-byte hash> */
3361#define EOIE_SIZE_WITH_HEADER (4 + 4 + EOIE_SIZE) /* <4-byte signature> + <4-byte length> + EOIE_SIZE */
3362
3363static size_t read_eoie_extension(const char *mmap, size_t mmap_size)
3364{
3365        /*
3366         * The end of index entries (EOIE) extension is guaranteed to be last
3367         * so that it can be found by scanning backwards from the EOF.
3368         *
3369         * "EOIE"
3370         * <4-byte length>
3371         * <4-byte offset>
3372         * <20-byte hash>
3373         */
3374        const char *index, *eoie;
3375        uint32_t extsize;
3376        size_t offset, src_offset;
3377        unsigned char hash[GIT_MAX_RAWSZ];
3378        git_hash_ctx c;
3379
3380        /* ensure we have an index big enough to contain an EOIE extension */
3381        if (mmap_size < sizeof(struct cache_header) + EOIE_SIZE_WITH_HEADER + the_hash_algo->rawsz)
3382                return 0;
3383
3384        /* validate the extension signature */
3385        index = eoie = mmap + mmap_size - EOIE_SIZE_WITH_HEADER - the_hash_algo->rawsz;
3386        if (CACHE_EXT(index) != CACHE_EXT_ENDOFINDEXENTRIES)
3387                return 0;
3388        index += sizeof(uint32_t);
3389
3390        /* validate the extension size */
3391        extsize = get_be32(index);
3392        if (extsize != EOIE_SIZE)
3393                return 0;
3394        index += sizeof(uint32_t);
3395
3396        /*
3397         * Validate the offset we're going to look for the first extension
3398         * signature is after the index header and before the eoie extension.
3399         */
3400        offset = get_be32(index);
3401        if (mmap + offset < mmap + sizeof(struct cache_header))
3402                return 0;
3403        if (mmap + offset >= eoie)
3404                return 0;
3405        index += sizeof(uint32_t);
3406
3407        /*
3408         * The hash is computed over extension types and their sizes (but not
3409         * their contents).  E.g. if we have "TREE" extension that is N-bytes
3410         * long, "REUC" extension that is M-bytes long, followed by "EOIE",
3411         * then the hash would be:
3412         *
3413         * SHA-1("TREE" + <binary representation of N> +
3414         *       "REUC" + <binary representation of M>)
3415         */
3416        src_offset = offset;
3417        the_hash_algo->init_fn(&c);
3418        while (src_offset < mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER) {
3419                /* After an array of active_nr index entries,
3420                 * there can be arbitrary number of extended
3421                 * sections, each of which is prefixed with
3422                 * extension name (4-byte) and section length
3423                 * in 4-byte network byte order.
3424                 */
3425                uint32_t extsize;
3426                memcpy(&extsize, mmap + src_offset + 4, 4);
3427                extsize = ntohl(extsize);
3428
3429                /* verify the extension size isn't so large it will wrap around */
3430                if (src_offset + 8 + extsize < src_offset)
3431                        return 0;
3432
3433                the_hash_algo->update_fn(&c, mmap + src_offset, 8);
3434
3435                src_offset += 8;
3436                src_offset += extsize;
3437        }
3438        the_hash_algo->final_fn(hash, &c);
3439        if (!hasheq(hash, (const unsigned char *)index))
3440                return 0;
3441
3442        /* Validate that the extension offsets returned us back to the eoie extension. */
3443        if (src_offset != mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER)
3444                return 0;
3445
3446        return offset;
3447}
3448
3449static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset)
3450{
3451        uint32_t buffer;
3452        unsigned char hash[GIT_MAX_RAWSZ];
3453
3454        /* offset */
3455        put_be32(&buffer, offset);
3456        strbuf_add(sb, &buffer, sizeof(uint32_t));
3457
3458        /* hash */
3459        the_hash_algo->final_fn(hash, eoie_context);
3460        strbuf_add(sb, hash, the_hash_algo->rawsz);
3461}
3462
3463#define IEOT_VERSION    (1)
3464
3465static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset)
3466{
3467       const char *index = NULL;
3468       uint32_t extsize, ext_version;
3469       struct index_entry_offset_table *ieot;
3470       int i, nr;
3471
3472       /* find the IEOT extension */
3473       if (!offset)
3474               return NULL;
3475       while (offset <= mmap_size - the_hash_algo->rawsz - 8) {
3476               extsize = get_be32(mmap + offset + 4);
3477               if (CACHE_EXT((mmap + offset)) == CACHE_EXT_INDEXENTRYOFFSETTABLE) {
3478                       index = mmap + offset + 4 + 4;
3479                       break;
3480               }
3481               offset += 8;
3482               offset += extsize;
3483       }
3484       if (!index)
3485               return NULL;
3486
3487       /* validate the version is IEOT_VERSION */
3488       ext_version = get_be32(index);
3489       if (ext_version != IEOT_VERSION) {
3490               error("invalid IEOT version %d", ext_version);
3491               return NULL;
3492       }
3493       index += sizeof(uint32_t);
3494
3495       /* extension size - version bytes / bytes per entry */
3496       nr = (extsize - sizeof(uint32_t)) / (sizeof(uint32_t) + sizeof(uint32_t));
3497       if (!nr) {
3498               error("invalid number of IEOT entries %d", nr);
3499               return NULL;
3500       }
3501       ieot = xmalloc(sizeof(struct index_entry_offset_table)
3502               + (nr * sizeof(struct index_entry_offset)));
3503       ieot->nr = nr;
3504       for (i = 0; i < nr; i++) {
3505               ieot->entries[i].offset = get_be32(index);
3506               index += sizeof(uint32_t);
3507               ieot->entries[i].nr = get_be32(index);
3508               index += sizeof(uint32_t);
3509       }
3510
3511       return ieot;
3512}
3513
3514static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot)
3515{
3516       uint32_t buffer;
3517       int i;
3518
3519       /* version */
3520       put_be32(&buffer, IEOT_VERSION);
3521       strbuf_add(sb, &buffer, sizeof(uint32_t));
3522
3523       /* ieot */
3524       for (i = 0; i < ieot->nr; i++) {
3525
3526               /* offset */
3527               put_be32(&buffer, ieot->entries[i].offset);
3528               strbuf_add(sb, &buffer, sizeof(uint32_t));
3529
3530               /* count */
3531               put_be32(&buffer, ieot->entries[i].nr);
3532               strbuf_add(sb, &buffer, sizeof(uint32_t));
3533       }
3534}