read-cache.con commit sequencer: don't say BUG on bogus input (c5e358d)
   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 "tempfile.h"
  10#include "lockfile.h"
  11#include "cache-tree.h"
  12#include "refs.h"
  13#include "dir.h"
  14#include "tree.h"
  15#include "commit.h"
  16#include "blob.h"
  17#include "resolve-undo.h"
  18#include "strbuf.h"
  19#include "varint.h"
  20#include "split-index.h"
  21#include "utf8.h"
  22#include "fsmonitor.h"
  23
  24/* Mask for the name length in ce_flags in the on-disk index */
  25
  26#define CE_NAMEMASK  (0x0fff)
  27
  28/* Index extensions.
  29 *
  30 * The first letter should be 'A'..'Z' for extensions that are not
  31 * necessary for a correct operation (i.e. optimization data).
  32 * When new extensions are added that _needs_ to be understood in
  33 * order to correctly interpret the index file, pick character that
  34 * is outside the range, to cause the reader to abort.
  35 */
  36
  37#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  38#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  39#define CACHE_EXT_RESOLVE_UNDO 0x52455543 /* "REUC" */
  40#define CACHE_EXT_LINK 0x6c696e6b         /* "link" */
  41#define CACHE_EXT_UNTRACKED 0x554E5452    /* "UNTR" */
  42#define CACHE_EXT_FSMONITOR 0x46534D4E    /* "FSMN" */
  43
  44/* changes that can be kept in $GIT_DIR/index (basically all extensions) */
  45#define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \
  46                 CE_ENTRY_ADDED | CE_ENTRY_REMOVED | CE_ENTRY_CHANGED | \
  47                 SPLIT_INDEX_ORDERED | UNTRACKED_CHANGED | FSMONITOR_CHANGED)
  48
  49struct index_state the_index;
  50static const char *alternate_index_output;
  51
  52static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  53{
  54        istate->cache[nr] = ce;
  55        add_name_hash(istate, ce);
  56}
  57
  58static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  59{
  60        struct cache_entry *old = istate->cache[nr];
  61
  62        replace_index_entry_in_base(istate, old, ce);
  63        remove_name_hash(istate, old);
  64        free(old);
  65        set_index_entry(istate, nr, ce);
  66        ce->ce_flags |= CE_UPDATE_IN_BASE;
  67        mark_fsmonitor_invalid(istate, ce);
  68        istate->cache_changed |= CE_ENTRY_CHANGED;
  69}
  70
  71void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
  72{
  73        struct cache_entry *old = istate->cache[nr], *new;
  74        int namelen = strlen(new_name);
  75
  76        new = xmalloc(cache_entry_size(namelen));
  77        copy_cache_entry(new, old);
  78        new->ce_flags &= ~CE_HASHED;
  79        new->ce_namelen = namelen;
  80        new->index = 0;
  81        memcpy(new->name, new_name, namelen + 1);
  82
  83        cache_tree_invalidate_path(istate, old->name);
  84        untracked_cache_remove_from_index(istate, old->name);
  85        remove_index_entry_at(istate, nr);
  86        add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
  87}
  88
  89void fill_stat_data(struct stat_data *sd, struct stat *st)
  90{
  91        sd->sd_ctime.sec = (unsigned int)st->st_ctime;
  92        sd->sd_mtime.sec = (unsigned int)st->st_mtime;
  93        sd->sd_ctime.nsec = ST_CTIME_NSEC(*st);
  94        sd->sd_mtime.nsec = ST_MTIME_NSEC(*st);
  95        sd->sd_dev = st->st_dev;
  96        sd->sd_ino = st->st_ino;
  97        sd->sd_uid = st->st_uid;
  98        sd->sd_gid = st->st_gid;
  99        sd->sd_size = st->st_size;
 100}
 101
 102int match_stat_data(const struct stat_data *sd, struct stat *st)
 103{
 104        int changed = 0;
 105
 106        if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
 107                changed |= MTIME_CHANGED;
 108        if (trust_ctime && check_stat &&
 109            sd->sd_ctime.sec != (unsigned int)st->st_ctime)
 110                changed |= CTIME_CHANGED;
 111
 112#ifdef USE_NSEC
 113        if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
 114                changed |= MTIME_CHANGED;
 115        if (trust_ctime && check_stat &&
 116            sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
 117                changed |= CTIME_CHANGED;
 118#endif
 119
 120        if (check_stat) {
 121                if (sd->sd_uid != (unsigned int) st->st_uid ||
 122                        sd->sd_gid != (unsigned int) st->st_gid)
 123                        changed |= OWNER_CHANGED;
 124                if (sd->sd_ino != (unsigned int) st->st_ino)
 125                        changed |= INODE_CHANGED;
 126        }
 127
 128#ifdef USE_STDEV
 129        /*
 130         * st_dev breaks on network filesystems where different
 131         * clients will have different views of what "device"
 132         * the filesystem is on
 133         */
 134        if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
 135                        changed |= INODE_CHANGED;
 136#endif
 137
 138        if (sd->sd_size != (unsigned int) st->st_size)
 139                changed |= DATA_CHANGED;
 140
 141        return changed;
 142}
 143
 144/*
 145 * This only updates the "non-critical" parts of the directory
 146 * cache, ie the parts that aren't tracked by GIT, and only used
 147 * to validate the cache.
 148 */
 149void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 150{
 151        fill_stat_data(&ce->ce_stat_data, st);
 152
 153        if (assume_unchanged)
 154                ce->ce_flags |= CE_VALID;
 155
 156        if (S_ISREG(st->st_mode)) {
 157                ce_mark_uptodate(ce);
 158                mark_fsmonitor_valid(ce);
 159        }
 160}
 161
 162static int ce_compare_data(const struct cache_entry *ce, struct stat *st)
 163{
 164        int match = -1;
 165        int fd = git_open_cloexec(ce->name, O_RDONLY);
 166
 167        if (fd >= 0) {
 168                struct object_id oid;
 169                if (!index_fd(&oid, fd, st, OBJ_BLOB, ce->name, 0))
 170                        match = oidcmp(&oid, &ce->oid);
 171                /* index_fd() closed the file descriptor already */
 172        }
 173        return match;
 174}
 175
 176static int ce_compare_link(const struct cache_entry *ce, size_t expected_size)
 177{
 178        int match = -1;
 179        void *buffer;
 180        unsigned long size;
 181        enum object_type type;
 182        struct strbuf sb = STRBUF_INIT;
 183
 184        if (strbuf_readlink(&sb, ce->name, expected_size))
 185                return -1;
 186
 187        buffer = read_sha1_file(ce->oid.hash, &type, &size);
 188        if (buffer) {
 189                if (size == sb.len)
 190                        match = memcmp(buffer, sb.buf, size);
 191                free(buffer);
 192        }
 193        strbuf_release(&sb);
 194        return match;
 195}
 196
 197static int ce_compare_gitlink(const struct cache_entry *ce)
 198{
 199        struct object_id oid;
 200
 201        /*
 202         * We don't actually require that the .git directory
 203         * under GITLINK directory be a valid git directory. It
 204         * might even be missing (in case nobody populated that
 205         * sub-project).
 206         *
 207         * If so, we consider it always to match.
 208         */
 209        if (resolve_gitlink_ref(ce->name, "HEAD", &oid) < 0)
 210                return 0;
 211        return oidcmp(&oid, &ce->oid);
 212}
 213
 214static int ce_modified_check_fs(const struct cache_entry *ce, struct stat *st)
 215{
 216        switch (st->st_mode & S_IFMT) {
 217        case S_IFREG:
 218                if (ce_compare_data(ce, st))
 219                        return DATA_CHANGED;
 220                break;
 221        case S_IFLNK:
 222                if (ce_compare_link(ce, xsize_t(st->st_size)))
 223                        return DATA_CHANGED;
 224                break;
 225        case S_IFDIR:
 226                if (S_ISGITLINK(ce->ce_mode))
 227                        return ce_compare_gitlink(ce) ? DATA_CHANGED : 0;
 228                /* else fallthrough */
 229        default:
 230                return TYPE_CHANGED;
 231        }
 232        return 0;
 233}
 234
 235static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 236{
 237        unsigned int changed = 0;
 238
 239        if (ce->ce_flags & CE_REMOVE)
 240                return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 241
 242        switch (ce->ce_mode & S_IFMT) {
 243        case S_IFREG:
 244                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 245                /* We consider only the owner x bit to be relevant for
 246                 * "mode changes"
 247                 */
 248                if (trust_executable_bit &&
 249                    (0100 & (ce->ce_mode ^ st->st_mode)))
 250                        changed |= MODE_CHANGED;
 251                break;
 252        case S_IFLNK:
 253                if (!S_ISLNK(st->st_mode) &&
 254                    (has_symlinks || !S_ISREG(st->st_mode)))
 255                        changed |= TYPE_CHANGED;
 256                break;
 257        case S_IFGITLINK:
 258                /* We ignore most of the st_xxx fields for gitlinks */
 259                if (!S_ISDIR(st->st_mode))
 260                        changed |= TYPE_CHANGED;
 261                else if (ce_compare_gitlink(ce))
 262                        changed |= DATA_CHANGED;
 263                return changed;
 264        default:
 265                die("internal error: ce_mode is %o", ce->ce_mode);
 266        }
 267
 268        changed |= match_stat_data(&ce->ce_stat_data, st);
 269
 270        /* Racily smudged entry? */
 271        if (!ce->ce_stat_data.sd_size) {
 272                if (!is_empty_blob_sha1(ce->oid.hash))
 273                        changed |= DATA_CHANGED;
 274        }
 275
 276        return changed;
 277}
 278
 279static int is_racy_stat(const struct index_state *istate,
 280                        const struct stat_data *sd)
 281{
 282        return (istate->timestamp.sec &&
 283#ifdef USE_NSEC
 284                 /* nanosecond timestamped files can also be racy! */
 285                (istate->timestamp.sec < sd->sd_mtime.sec ||
 286                 (istate->timestamp.sec == sd->sd_mtime.sec &&
 287                  istate->timestamp.nsec <= sd->sd_mtime.nsec))
 288#else
 289                istate->timestamp.sec <= sd->sd_mtime.sec
 290#endif
 291                );
 292}
 293
 294static int is_racy_timestamp(const struct index_state *istate,
 295                             const struct cache_entry *ce)
 296{
 297        return (!S_ISGITLINK(ce->ce_mode) &&
 298                is_racy_stat(istate, &ce->ce_stat_data));
 299}
 300
 301int match_stat_data_racy(const struct index_state *istate,
 302                         const struct stat_data *sd, struct stat *st)
 303{
 304        if (is_racy_stat(istate, sd))
 305                return MTIME_CHANGED;
 306        return match_stat_data(sd, st);
 307}
 308
 309int ie_match_stat(struct index_state *istate,
 310                  const struct cache_entry *ce, struct stat *st,
 311                  unsigned int options)
 312{
 313        unsigned int changed;
 314        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 315        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
 316        int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 317        int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR;
 318
 319        if (!ignore_fsmonitor)
 320                refresh_fsmonitor(istate);
 321        /*
 322         * If it's marked as always valid in the index, it's
 323         * valid whatever the checked-out copy says.
 324         *
 325         * skip-worktree has the same effect with higher precedence
 326         */
 327        if (!ignore_skip_worktree && ce_skip_worktree(ce))
 328                return 0;
 329        if (!ignore_valid && (ce->ce_flags & CE_VALID))
 330                return 0;
 331        if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID))
 332                return 0;
 333
 334        /*
 335         * Intent-to-add entries have not been added, so the index entry
 336         * by definition never matches what is in the work tree until it
 337         * actually gets added.
 338         */
 339        if (ce_intent_to_add(ce))
 340                return DATA_CHANGED | TYPE_CHANGED | MODE_CHANGED;
 341
 342        changed = ce_match_stat_basic(ce, st);
 343
 344        /*
 345         * Within 1 second of this sequence:
 346         *      echo xyzzy >file && git-update-index --add file
 347         * running this command:
 348         *      echo frotz >file
 349         * would give a falsely clean cache entry.  The mtime and
 350         * length match the cache, and other stat fields do not change.
 351         *
 352         * We could detect this at update-index time (the cache entry
 353         * being registered/updated records the same time as "now")
 354         * and delay the return from git-update-index, but that would
 355         * effectively mean we can make at most one commit per second,
 356         * which is not acceptable.  Instead, we check cache entries
 357         * whose mtime are the same as the index file timestamp more
 358         * carefully than others.
 359         */
 360        if (!changed && is_racy_timestamp(istate, ce)) {
 361                if (assume_racy_is_modified)
 362                        changed |= DATA_CHANGED;
 363                else
 364                        changed |= ce_modified_check_fs(ce, st);
 365        }
 366
 367        return changed;
 368}
 369
 370int ie_modified(struct index_state *istate,
 371                const struct cache_entry *ce,
 372                struct stat *st, unsigned int options)
 373{
 374        int changed, changed_fs;
 375
 376        changed = ie_match_stat(istate, ce, st, options);
 377        if (!changed)
 378                return 0;
 379        /*
 380         * If the mode or type has changed, there's no point in trying
 381         * to refresh the entry - it's not going to match
 382         */
 383        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 384                return changed;
 385
 386        /*
 387         * Immediately after read-tree or update-index --cacheinfo,
 388         * the length field is zero, as we have never even read the
 389         * lstat(2) information once, and we cannot trust DATA_CHANGED
 390         * returned by ie_match_stat() which in turn was returned by
 391         * ce_match_stat_basic() to signal that the filesize of the
 392         * blob changed.  We have to actually go to the filesystem to
 393         * see if the contents match, and if so, should answer "unchanged".
 394         *
 395         * The logic does not apply to gitlinks, as ce_match_stat_basic()
 396         * already has checked the actual HEAD from the filesystem in the
 397         * subproject.  If ie_match_stat() already said it is different,
 398         * then we know it is.
 399         */
 400        if ((changed & DATA_CHANGED) &&
 401            (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0))
 402                return changed;
 403
 404        changed_fs = ce_modified_check_fs(ce, st);
 405        if (changed_fs)
 406                return changed | changed_fs;
 407        return 0;
 408}
 409
 410int base_name_compare(const char *name1, int len1, int mode1,
 411                      const char *name2, int len2, int mode2)
 412{
 413        unsigned char c1, c2;
 414        int len = len1 < len2 ? len1 : len2;
 415        int cmp;
 416
 417        cmp = memcmp(name1, name2, len);
 418        if (cmp)
 419                return cmp;
 420        c1 = name1[len];
 421        c2 = name2[len];
 422        if (!c1 && S_ISDIR(mode1))
 423                c1 = '/';
 424        if (!c2 && S_ISDIR(mode2))
 425                c2 = '/';
 426        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 427}
 428
 429/*
 430 * df_name_compare() is identical to base_name_compare(), except it
 431 * compares conflicting directory/file entries as equal. Note that
 432 * while a directory name compares as equal to a regular file, they
 433 * then individually compare _differently_ to a filename that has
 434 * a dot after the basename (because '\0' < '.' < '/').
 435 *
 436 * This is used by routines that want to traverse the git namespace
 437 * but then handle conflicting entries together when possible.
 438 */
 439int df_name_compare(const char *name1, int len1, int mode1,
 440                    const char *name2, int len2, int mode2)
 441{
 442        int len = len1 < len2 ? len1 : len2, cmp;
 443        unsigned char c1, c2;
 444
 445        cmp = memcmp(name1, name2, len);
 446        if (cmp)
 447                return cmp;
 448        /* Directories and files compare equal (same length, same name) */
 449        if (len1 == len2)
 450                return 0;
 451        c1 = name1[len];
 452        if (!c1 && S_ISDIR(mode1))
 453                c1 = '/';
 454        c2 = name2[len];
 455        if (!c2 && S_ISDIR(mode2))
 456                c2 = '/';
 457        if (c1 == '/' && !c2)
 458                return 0;
 459        if (c2 == '/' && !c1)
 460                return 0;
 461        return c1 - c2;
 462}
 463
 464int name_compare(const char *name1, size_t len1, const char *name2, size_t len2)
 465{
 466        size_t min_len = (len1 < len2) ? len1 : len2;
 467        int cmp = memcmp(name1, name2, min_len);
 468        if (cmp)
 469                return cmp;
 470        if (len1 < len2)
 471                return -1;
 472        if (len1 > len2)
 473                return 1;
 474        return 0;
 475}
 476
 477int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
 478{
 479        int cmp;
 480
 481        cmp = name_compare(name1, len1, name2, len2);
 482        if (cmp)
 483                return cmp;
 484
 485        if (stage1 < stage2)
 486                return -1;
 487        if (stage1 > stage2)
 488                return 1;
 489        return 0;
 490}
 491
 492static int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage)
 493{
 494        int first, last;
 495
 496        first = 0;
 497        last = istate->cache_nr;
 498        while (last > first) {
 499                int next = (last + first) >> 1;
 500                struct cache_entry *ce = istate->cache[next];
 501                int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce));
 502                if (!cmp)
 503                        return next;
 504                if (cmp < 0) {
 505                        last = next;
 506                        continue;
 507                }
 508                first = next+1;
 509        }
 510        return -first-1;
 511}
 512
 513int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 514{
 515        return index_name_stage_pos(istate, name, namelen, 0);
 516}
 517
 518int remove_index_entry_at(struct index_state *istate, int pos)
 519{
 520        struct cache_entry *ce = istate->cache[pos];
 521
 522        record_resolve_undo(istate, ce);
 523        remove_name_hash(istate, ce);
 524        save_or_free_index_entry(istate, ce);
 525        istate->cache_changed |= CE_ENTRY_REMOVED;
 526        istate->cache_nr--;
 527        if (pos >= istate->cache_nr)
 528                return 0;
 529        MOVE_ARRAY(istate->cache + pos, istate->cache + pos + 1,
 530                   istate->cache_nr - pos);
 531        return 1;
 532}
 533
 534/*
 535 * Remove all cache entries marked for removal, that is where
 536 * CE_REMOVE is set in ce_flags.  This is much more effective than
 537 * calling remove_index_entry_at() for each entry to be removed.
 538 */
 539void remove_marked_cache_entries(struct index_state *istate)
 540{
 541        struct cache_entry **ce_array = istate->cache;
 542        unsigned int i, j;
 543
 544        for (i = j = 0; i < istate->cache_nr; i++) {
 545                if (ce_array[i]->ce_flags & CE_REMOVE) {
 546                        remove_name_hash(istate, ce_array[i]);
 547                        save_or_free_index_entry(istate, ce_array[i]);
 548                }
 549                else
 550                        ce_array[j++] = ce_array[i];
 551        }
 552        if (j == istate->cache_nr)
 553                return;
 554        istate->cache_changed |= CE_ENTRY_REMOVED;
 555        istate->cache_nr = j;
 556}
 557
 558int remove_file_from_index(struct index_state *istate, const char *path)
 559{
 560        int pos = index_name_pos(istate, path, strlen(path));
 561        if (pos < 0)
 562                pos = -pos-1;
 563        cache_tree_invalidate_path(istate, path);
 564        untracked_cache_remove_from_index(istate, path);
 565        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 566                remove_index_entry_at(istate, pos);
 567        return 0;
 568}
 569
 570static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 571{
 572        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 573}
 574
 575static int index_name_pos_also_unmerged(struct index_state *istate,
 576        const char *path, int namelen)
 577{
 578        int pos = index_name_pos(istate, path, namelen);
 579        struct cache_entry *ce;
 580
 581        if (pos >= 0)
 582                return pos;
 583
 584        /* maybe unmerged? */
 585        pos = -1 - pos;
 586        if (pos >= istate->cache_nr ||
 587                        compare_name((ce = istate->cache[pos]), path, namelen))
 588                return -1;
 589
 590        /* order of preference: stage 2, 1, 3 */
 591        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 592                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 593                        !compare_name(ce, path, namelen))
 594                pos++;
 595        return pos;
 596}
 597
 598static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 599{
 600        int len = ce_namelen(ce);
 601        return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 602}
 603
 604/*
 605 * If we add a filename that aliases in the cache, we will use the
 606 * name that we already have - but we don't want to update the same
 607 * alias twice, because that implies that there were actually two
 608 * different files with aliasing names!
 609 *
 610 * So we use the CE_ADDED flag to verify that the alias was an old
 611 * one before we accept it as
 612 */
 613static struct cache_entry *create_alias_ce(struct index_state *istate,
 614                                           struct cache_entry *ce,
 615                                           struct cache_entry *alias)
 616{
 617        int len;
 618        struct cache_entry *new;
 619
 620        if (alias->ce_flags & CE_ADDED)
 621                die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 622
 623        /* Ok, create the new entry using the name of the existing alias */
 624        len = ce_namelen(alias);
 625        new = xcalloc(1, cache_entry_size(len));
 626        memcpy(new->name, alias->name, len);
 627        copy_cache_entry(new, ce);
 628        save_or_free_index_entry(istate, ce);
 629        return new;
 630}
 631
 632void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 633{
 634        unsigned char sha1[20];
 635        if (write_sha1_file("", 0, blob_type, sha1))
 636                die("cannot create an empty blob in the object database");
 637        hashcpy(ce->oid.hash, sha1);
 638}
 639
 640int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 641{
 642        int size, namelen, was_same;
 643        mode_t st_mode = st->st_mode;
 644        struct cache_entry *ce, *alias = NULL;
 645        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE|CE_MATCH_RACY_IS_DIRTY;
 646        int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 647        int pretend = flags & ADD_CACHE_PRETEND;
 648        int intent_only = flags & ADD_CACHE_INTENT;
 649        int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 650                          (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 651        int newflags = HASH_WRITE_OBJECT;
 652
 653        if (flags & HASH_RENORMALIZE)
 654                newflags |= HASH_RENORMALIZE;
 655
 656        if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 657                return error("%s: can only add regular files, symbolic links or git-directories", path);
 658
 659        namelen = strlen(path);
 660        if (S_ISDIR(st_mode)) {
 661                while (namelen && path[namelen-1] == '/')
 662                        namelen--;
 663        }
 664        size = cache_entry_size(namelen);
 665        ce = xcalloc(1, size);
 666        memcpy(ce->name, path, namelen);
 667        ce->ce_namelen = namelen;
 668        if (!intent_only)
 669                fill_stat_cache_info(ce, st);
 670        else
 671                ce->ce_flags |= CE_INTENT_TO_ADD;
 672
 673
 674        if (trust_executable_bit && has_symlinks) {
 675                ce->ce_mode = create_ce_mode(st_mode);
 676        } else {
 677                /* If there is an existing entry, pick the mode bits and type
 678                 * from it, otherwise assume unexecutable regular file.
 679                 */
 680                struct cache_entry *ent;
 681                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 682
 683                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 684                ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 685        }
 686
 687        /* When core.ignorecase=true, determine if a directory of the same name but differing
 688         * case already exists within the Git repository.  If it does, ensure the directory
 689         * case of the file being added to the repository matches (is folded into) the existing
 690         * entry's directory case.
 691         */
 692        if (ignore_case) {
 693                adjust_dirname_case(istate, ce->name);
 694        }
 695        if (!(flags & HASH_RENORMALIZE)) {
 696                alias = index_file_exists(istate, ce->name,
 697                                          ce_namelen(ce), ignore_case);
 698                if (alias &&
 699                    !ce_stage(alias) &&
 700                    !ie_match_stat(istate, alias, st, ce_option)) {
 701                        /* Nothing changed, really */
 702                        if (!S_ISGITLINK(alias->ce_mode))
 703                                ce_mark_uptodate(alias);
 704                        alias->ce_flags |= CE_ADDED;
 705
 706                        free(ce);
 707                        return 0;
 708                }
 709        }
 710        if (!intent_only) {
 711                if (index_path(&ce->oid, path, st, newflags)) {
 712                        free(ce);
 713                        return error("unable to index file %s", path);
 714                }
 715        } else
 716                set_object_name_for_intent_to_add_entry(ce);
 717
 718        if (ignore_case && alias && different_name(ce, alias))
 719                ce = create_alias_ce(istate, ce, alias);
 720        ce->ce_flags |= CE_ADDED;
 721
 722        /* It was suspected to be racily clean, but it turns out to be Ok */
 723        was_same = (alias &&
 724                    !ce_stage(alias) &&
 725                    !oidcmp(&alias->oid, &ce->oid) &&
 726                    ce->ce_mode == alias->ce_mode);
 727
 728        if (pretend)
 729                free(ce);
 730        else if (add_index_entry(istate, ce, add_option)) {
 731                free(ce);
 732                return error("unable to add %s to index", path);
 733        }
 734        if (verbose && !was_same)
 735                printf("add '%s'\n", path);
 736        return 0;
 737}
 738
 739int add_file_to_index(struct index_state *istate, const char *path, int flags)
 740{
 741        struct stat st;
 742        if (lstat(path, &st))
 743                die_errno("unable to stat '%s'", path);
 744        return add_to_index(istate, path, &st, flags);
 745}
 746
 747struct cache_entry *make_cache_entry(unsigned int mode,
 748                const unsigned char *sha1, const char *path, int stage,
 749                unsigned int refresh_options)
 750{
 751        int size, len;
 752        struct cache_entry *ce, *ret;
 753
 754        if (!verify_path(path, mode)) {
 755                error("Invalid path '%s'", path);
 756                return NULL;
 757        }
 758
 759        len = strlen(path);
 760        size = cache_entry_size(len);
 761        ce = xcalloc(1, size);
 762
 763        hashcpy(ce->oid.hash, sha1);
 764        memcpy(ce->name, path, len);
 765        ce->ce_flags = create_ce_flags(stage);
 766        ce->ce_namelen = len;
 767        ce->ce_mode = create_ce_mode(mode);
 768
 769        ret = refresh_cache_entry(ce, refresh_options);
 770        if (ret != ce)
 771                free(ce);
 772        return ret;
 773}
 774
 775/*
 776 * Chmod an index entry with either +x or -x.
 777 *
 778 * Returns -1 if the chmod for the particular cache entry failed (if it's
 779 * not a regular file), -2 if an invalid flip argument is passed in, 0
 780 * otherwise.
 781 */
 782int chmod_index_entry(struct index_state *istate, struct cache_entry *ce,
 783                      char flip)
 784{
 785        if (!S_ISREG(ce->ce_mode))
 786                return -1;
 787        switch (flip) {
 788        case '+':
 789                ce->ce_mode |= 0111;
 790                break;
 791        case '-':
 792                ce->ce_mode &= ~0111;
 793                break;
 794        default:
 795                return -2;
 796        }
 797        cache_tree_invalidate_path(istate, ce->name);
 798        ce->ce_flags |= CE_UPDATE_IN_BASE;
 799        mark_fsmonitor_invalid(istate, ce);
 800        istate->cache_changed |= CE_ENTRY_CHANGED;
 801
 802        return 0;
 803}
 804
 805int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 806{
 807        int len = ce_namelen(a);
 808        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 809}
 810
 811/*
 812 * We fundamentally don't like some paths: we don't want
 813 * dot or dot-dot anywhere, and for obvious reasons don't
 814 * want to recurse into ".git" either.
 815 *
 816 * Also, we don't want double slashes or slashes at the
 817 * end that can make pathnames ambiguous.
 818 */
 819static int verify_dotfile(const char *rest, unsigned mode)
 820{
 821        /*
 822         * The first character was '.', but that
 823         * has already been discarded, we now test
 824         * the rest.
 825         */
 826
 827        /* "." is not allowed */
 828        if (*rest == '\0' || is_dir_sep(*rest))
 829                return 0;
 830
 831        switch (*rest) {
 832        /*
 833         * ".git" followed by NUL or slash is bad. Note that we match
 834         * case-insensitively here, even if ignore_case is not set.
 835         * This outlaws ".GIT" everywhere out of an abundance of caution,
 836         * since there's really no good reason to allow it.
 837         *
 838         * Once we've seen ".git", we can also find ".gitmodules", etc (also
 839         * case-insensitively).
 840         */
 841        case 'g':
 842        case 'G':
 843                if (rest[1] != 'i' && rest[1] != 'I')
 844                        break;
 845                if (rest[2] != 't' && rest[2] != 'T')
 846                        break;
 847                if (rest[3] == '\0' || is_dir_sep(rest[3]))
 848                        return 0;
 849                if (S_ISLNK(mode)) {
 850                        rest += 3;
 851                        if (skip_iprefix(rest, "modules", &rest) &&
 852                            (*rest == '\0' || is_dir_sep(*rest)))
 853                                return 0;
 854                }
 855                break;
 856        case '.':
 857                if (rest[1] == '\0' || is_dir_sep(rest[1]))
 858                        return 0;
 859        }
 860        return 1;
 861}
 862
 863int verify_path(const char *path, unsigned mode)
 864{
 865        char c;
 866
 867        if (has_dos_drive_prefix(path))
 868                return 0;
 869
 870        goto inside;
 871        for (;;) {
 872                if (!c)
 873                        return 1;
 874                if (is_dir_sep(c)) {
 875inside:
 876                        if (protect_hfs) {
 877                                if (is_hfs_dotgit(path))
 878                                        return 0;
 879                                if (S_ISLNK(mode)) {
 880                                        if (is_hfs_dotgitmodules(path))
 881                                                return 0;
 882                                }
 883                        }
 884                        if (protect_ntfs) {
 885                                if (is_ntfs_dotgit(path))
 886                                        return 0;
 887                                if (S_ISLNK(mode)) {
 888                                        if (is_ntfs_dotgitmodules(path))
 889                                                return 0;
 890                                }
 891                        }
 892
 893                        c = *path++;
 894                        if ((c == '.' && !verify_dotfile(path, mode)) ||
 895                            is_dir_sep(c) || c == '\0')
 896                                return 0;
 897                }
 898                c = *path++;
 899        }
 900}
 901
 902/*
 903 * Do we have another file that has the beginning components being a
 904 * proper superset of the name we're trying to add?
 905 */
 906static int has_file_name(struct index_state *istate,
 907                         const struct cache_entry *ce, int pos, int ok_to_replace)
 908{
 909        int retval = 0;
 910        int len = ce_namelen(ce);
 911        int stage = ce_stage(ce);
 912        const char *name = ce->name;
 913
 914        while (pos < istate->cache_nr) {
 915                struct cache_entry *p = istate->cache[pos++];
 916
 917                if (len >= ce_namelen(p))
 918                        break;
 919                if (memcmp(name, p->name, len))
 920                        break;
 921                if (ce_stage(p) != stage)
 922                        continue;
 923                if (p->name[len] != '/')
 924                        continue;
 925                if (p->ce_flags & CE_REMOVE)
 926                        continue;
 927                retval = -1;
 928                if (!ok_to_replace)
 929                        break;
 930                remove_index_entry_at(istate, --pos);
 931        }
 932        return retval;
 933}
 934
 935
 936/*
 937 * Like strcmp(), but also return the offset of the first change.
 938 * If strings are equal, return the length.
 939 */
 940int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
 941{
 942        size_t k;
 943
 944        if (!first_change)
 945                return strcmp(s1, s2);
 946
 947        for (k = 0; s1[k] == s2[k]; k++)
 948                if (s1[k] == '\0')
 949                        break;
 950
 951        *first_change = k;
 952        return (unsigned char)s1[k] - (unsigned char)s2[k];
 953}
 954
 955/*
 956 * Do we have another file with a pathname that is a proper
 957 * subset of the name we're trying to add?
 958 *
 959 * That is, is there another file in the index with a path
 960 * that matches a sub-directory in the given entry?
 961 */
 962static int has_dir_name(struct index_state *istate,
 963                        const struct cache_entry *ce, int pos, int ok_to_replace)
 964{
 965        int retval = 0;
 966        int stage = ce_stage(ce);
 967        const char *name = ce->name;
 968        const char *slash = name + ce_namelen(ce);
 969        size_t len_eq_last;
 970        int cmp_last = 0;
 971
 972        /*
 973         * We are frequently called during an iteration on a sorted
 974         * list of pathnames and while building a new index.  Therefore,
 975         * there is a high probability that this entry will eventually
 976         * be appended to the index, rather than inserted in the middle.
 977         * If we can confirm that, we can avoid binary searches on the
 978         * components of the pathname.
 979         *
 980         * Compare the entry's full path with the last path in the index.
 981         */
 982        if (istate->cache_nr > 0) {
 983                cmp_last = strcmp_offset(name,
 984                        istate->cache[istate->cache_nr - 1]->name,
 985                        &len_eq_last);
 986                if (cmp_last > 0) {
 987                        if (len_eq_last == 0) {
 988                                /*
 989                                 * The entry sorts AFTER the last one in the
 990                                 * index and their paths have no common prefix,
 991                                 * so there cannot be a F/D conflict.
 992                                 */
 993                                return retval;
 994                        } else {
 995                                /*
 996                                 * The entry sorts AFTER the last one in the
 997                                 * index, but has a common prefix.  Fall through
 998                                 * to the loop below to disect the entry's path
 999                                 * and see where the difference is.
1000                                 */
1001                        }
1002                } else if (cmp_last == 0) {
1003                        /*
1004                         * The entry exactly matches the last one in the
1005                         * index, but because of multiple stage and CE_REMOVE
1006                         * items, we fall through and let the regular search
1007                         * code handle it.
1008                         */
1009                }
1010        }
1011
1012        for (;;) {
1013                size_t len;
1014
1015                for (;;) {
1016                        if (*--slash == '/')
1017                                break;
1018                        if (slash <= ce->name)
1019                                return retval;
1020                }
1021                len = slash - name;
1022
1023                if (cmp_last > 0) {
1024                        /*
1025                         * (len + 1) is a directory boundary (including
1026                         * the trailing slash).  And since the loop is
1027                         * decrementing "slash", the first iteration is
1028                         * the longest directory prefix; subsequent
1029                         * iterations consider parent directories.
1030                         */
1031
1032                        if (len + 1 <= len_eq_last) {
1033                                /*
1034                                 * The directory prefix (including the trailing
1035                                 * slash) also appears as a prefix in the last
1036                                 * entry, so the remainder cannot collide (because
1037                                 * strcmp said the whole path was greater).
1038                                 *
1039                                 * EQ: last: xxx/A
1040                                 *     this: xxx/B
1041                                 *
1042                                 * LT: last: xxx/file_A
1043                                 *     this: xxx/file_B
1044                                 */
1045                                return retval;
1046                        }
1047
1048                        if (len > len_eq_last) {
1049                                /*
1050                                 * This part of the directory prefix (excluding
1051                                 * the trailing slash) is longer than the known
1052                                 * equal portions, so this sub-directory cannot
1053                                 * collide with a file.
1054                                 *
1055                                 * GT: last: xxxA
1056                                 *     this: xxxB/file
1057                                 */
1058                                return retval;
1059                        }
1060
1061                        if (istate->cache_nr > 0 &&
1062                                ce_namelen(istate->cache[istate->cache_nr - 1]) > len) {
1063                                /*
1064                                 * The directory prefix lines up with part of
1065                                 * a longer file or directory name, but sorts
1066                                 * after it, so this sub-directory cannot
1067                                 * collide with a file.
1068                                 *
1069                                 * last: xxx/yy-file (because '-' sorts before '/')
1070                                 * this: xxx/yy/abc
1071                                 */
1072                                return retval;
1073                        }
1074
1075                        /*
1076                         * This is a possible collision. Fall through and
1077                         * let the regular search code handle it.
1078                         *
1079                         * last: xxx
1080                         * this: xxx/file
1081                         */
1082                }
1083
1084                pos = index_name_stage_pos(istate, name, len, stage);
1085                if (pos >= 0) {
1086                        /*
1087                         * Found one, but not so fast.  This could
1088                         * be a marker that says "I was here, but
1089                         * I am being removed".  Such an entry is
1090                         * not a part of the resulting tree, and
1091                         * it is Ok to have a directory at the same
1092                         * path.
1093                         */
1094                        if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
1095                                retval = -1;
1096                                if (!ok_to_replace)
1097                                        break;
1098                                remove_index_entry_at(istate, pos);
1099                                continue;
1100                        }
1101                }
1102                else
1103                        pos = -pos-1;
1104
1105                /*
1106                 * Trivial optimization: if we find an entry that
1107                 * already matches the sub-directory, then we know
1108                 * we're ok, and we can exit.
1109                 */
1110                while (pos < istate->cache_nr) {
1111                        struct cache_entry *p = istate->cache[pos];
1112                        if ((ce_namelen(p) <= len) ||
1113                            (p->name[len] != '/') ||
1114                            memcmp(p->name, name, len))
1115                                break; /* not our subdirectory */
1116                        if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
1117                                /*
1118                                 * p is at the same stage as our entry, and
1119                                 * is a subdirectory of what we are looking
1120                                 * at, so we cannot have conflicts at our
1121                                 * level or anything shorter.
1122                                 */
1123                                return retval;
1124                        pos++;
1125                }
1126        }
1127        return retval;
1128}
1129
1130/* We may be in a situation where we already have path/file and path
1131 * is being added, or we already have path and path/file is being
1132 * added.  Either one would result in a nonsense tree that has path
1133 * twice when git-write-tree tries to write it out.  Prevent it.
1134 *
1135 * If ok-to-replace is specified, we remove the conflicting entries
1136 * from the cache so the caller should recompute the insert position.
1137 * When this happens, we return non-zero.
1138 */
1139static int check_file_directory_conflict(struct index_state *istate,
1140                                         const struct cache_entry *ce,
1141                                         int pos, int ok_to_replace)
1142{
1143        int retval;
1144
1145        /*
1146         * When ce is an "I am going away" entry, we allow it to be added
1147         */
1148        if (ce->ce_flags & CE_REMOVE)
1149                return 0;
1150
1151        /*
1152         * We check if the path is a sub-path of a subsequent pathname
1153         * first, since removing those will not change the position
1154         * in the array.
1155         */
1156        retval = has_file_name(istate, ce, pos, ok_to_replace);
1157
1158        /*
1159         * Then check if the path might have a clashing sub-directory
1160         * before it.
1161         */
1162        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
1163}
1164
1165static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
1166{
1167        int pos;
1168        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
1169        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
1170        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
1171        int new_only = option & ADD_CACHE_NEW_ONLY;
1172
1173        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1174                cache_tree_invalidate_path(istate, ce->name);
1175
1176        /*
1177         * If this entry's path sorts after the last entry in the index,
1178         * we can avoid searching for it.
1179         */
1180        if (istate->cache_nr > 0 &&
1181                strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
1182                pos = -istate->cache_nr - 1;
1183        else
1184                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1185
1186        /* existing match? Just replace it. */
1187        if (pos >= 0) {
1188                if (!new_only)
1189                        replace_index_entry(istate, pos, ce);
1190                return 0;
1191        }
1192        pos = -pos-1;
1193
1194        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1195                untracked_cache_add_to_index(istate, ce->name);
1196
1197        /*
1198         * Inserting a merged entry ("stage 0") into the index
1199         * will always replace all non-merged entries..
1200         */
1201        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
1202                while (ce_same_name(istate->cache[pos], ce)) {
1203                        ok_to_add = 1;
1204                        if (!remove_index_entry_at(istate, pos))
1205                                break;
1206                }
1207        }
1208
1209        if (!ok_to_add)
1210                return -1;
1211        if (!verify_path(ce->name, ce->ce_mode))
1212                return error("Invalid path '%s'", ce->name);
1213
1214        if (!skip_df_check &&
1215            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
1216                if (!ok_to_replace)
1217                        return error("'%s' appears as both a file and as a directory",
1218                                     ce->name);
1219                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1220                pos = -pos-1;
1221        }
1222        return pos + 1;
1223}
1224
1225int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
1226{
1227        int pos;
1228
1229        if (option & ADD_CACHE_JUST_APPEND)
1230                pos = istate->cache_nr;
1231        else {
1232                int ret;
1233                ret = add_index_entry_with_check(istate, ce, option);
1234                if (ret <= 0)
1235                        return ret;
1236                pos = ret - 1;
1237        }
1238
1239        /* Make sure the array is big enough .. */
1240        ALLOC_GROW(istate->cache, istate->cache_nr + 1, istate->cache_alloc);
1241
1242        /* Add it in.. */
1243        istate->cache_nr++;
1244        if (istate->cache_nr > pos + 1)
1245                memmove(istate->cache + pos + 1,
1246                        istate->cache + pos,
1247                        (istate->cache_nr - pos - 1) * sizeof(ce));
1248        set_index_entry(istate, pos, ce);
1249        istate->cache_changed |= CE_ENTRY_ADDED;
1250        return 0;
1251}
1252
1253/*
1254 * "refresh" does not calculate a new sha1 file or bring the
1255 * cache up-to-date for mode/content changes. But what it
1256 * _does_ do is to "re-match" the stat information of a file
1257 * with the cache, so that you can refresh the cache for a
1258 * file that hasn't been changed but where the stat entry is
1259 * out of date.
1260 *
1261 * For example, you'd want to do this after doing a "git-read-tree",
1262 * to link up the stat cache details with the proper files.
1263 */
1264static struct cache_entry *refresh_cache_ent(struct index_state *istate,
1265                                             struct cache_entry *ce,
1266                                             unsigned int options, int *err,
1267                                             int *changed_ret)
1268{
1269        struct stat st;
1270        struct cache_entry *updated;
1271        int changed, size;
1272        int refresh = options & CE_MATCH_REFRESH;
1273        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
1274        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
1275        int ignore_missing = options & CE_MATCH_IGNORE_MISSING;
1276        int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR;
1277
1278        if (!refresh || ce_uptodate(ce))
1279                return ce;
1280
1281        if (!ignore_fsmonitor)
1282                refresh_fsmonitor(istate);
1283        /*
1284         * CE_VALID or CE_SKIP_WORKTREE means the user promised us
1285         * that the change to the work tree does not matter and told
1286         * us not to worry.
1287         */
1288        if (!ignore_skip_worktree && ce_skip_worktree(ce)) {
1289                ce_mark_uptodate(ce);
1290                return ce;
1291        }
1292        if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
1293                ce_mark_uptodate(ce);
1294                return ce;
1295        }
1296        if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID)) {
1297                ce_mark_uptodate(ce);
1298                return ce;
1299        }
1300
1301        if (has_symlink_leading_path(ce->name, ce_namelen(ce))) {
1302                if (ignore_missing)
1303                        return ce;
1304                if (err)
1305                        *err = ENOENT;
1306                return NULL;
1307        }
1308
1309        if (lstat(ce->name, &st) < 0) {
1310                if (ignore_missing && errno == ENOENT)
1311                        return ce;
1312                if (err)
1313                        *err = errno;
1314                return NULL;
1315        }
1316
1317        changed = ie_match_stat(istate, ce, &st, options);
1318        if (changed_ret)
1319                *changed_ret = changed;
1320        if (!changed) {
1321                /*
1322                 * The path is unchanged.  If we were told to ignore
1323                 * valid bit, then we did the actual stat check and
1324                 * found that the entry is unmodified.  If the entry
1325                 * is not marked VALID, this is the place to mark it
1326                 * valid again, under "assume unchanged" mode.
1327                 */
1328                if (ignore_valid && assume_unchanged &&
1329                    !(ce->ce_flags & CE_VALID))
1330                        ; /* mark this one VALID again */
1331                else {
1332                        /*
1333                         * We do not mark the index itself "modified"
1334                         * because CE_UPTODATE flag is in-core only;
1335                         * we are not going to write this change out.
1336                         */
1337                        if (!S_ISGITLINK(ce->ce_mode)) {
1338                                ce_mark_uptodate(ce);
1339                                mark_fsmonitor_valid(ce);
1340                        }
1341                        return ce;
1342                }
1343        }
1344
1345        if (ie_modified(istate, ce, &st, options)) {
1346                if (err)
1347                        *err = EINVAL;
1348                return NULL;
1349        }
1350
1351        size = ce_size(ce);
1352        updated = xmalloc(size);
1353        memcpy(updated, ce, size);
1354        fill_stat_cache_info(updated, &st);
1355        /*
1356         * If ignore_valid is not set, we should leave CE_VALID bit
1357         * alone.  Otherwise, paths marked with --no-assume-unchanged
1358         * (i.e. things to be edited) will reacquire CE_VALID bit
1359         * automatically, which is not really what we want.
1360         */
1361        if (!ignore_valid && assume_unchanged &&
1362            !(ce->ce_flags & CE_VALID))
1363                updated->ce_flags &= ~CE_VALID;
1364
1365        /* istate->cache_changed is updated in the caller */
1366        return updated;
1367}
1368
1369static void show_file(const char * fmt, const char * name, int in_porcelain,
1370                      int * first, const char *header_msg)
1371{
1372        if (in_porcelain && *first && header_msg) {
1373                printf("%s\n", header_msg);
1374                *first = 0;
1375        }
1376        printf(fmt, name);
1377}
1378
1379int refresh_index(struct index_state *istate, unsigned int flags,
1380                  const struct pathspec *pathspec,
1381                  char *seen, const char *header_msg)
1382{
1383        int i;
1384        int has_errors = 0;
1385        int really = (flags & REFRESH_REALLY) != 0;
1386        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
1387        int quiet = (flags & REFRESH_QUIET) != 0;
1388        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
1389        int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
1390        int first = 1;
1391        int in_porcelain = (flags & REFRESH_IN_PORCELAIN);
1392        unsigned int options = (CE_MATCH_REFRESH |
1393                                (really ? CE_MATCH_IGNORE_VALID : 0) |
1394                                (not_new ? CE_MATCH_IGNORE_MISSING : 0));
1395        const char *modified_fmt;
1396        const char *deleted_fmt;
1397        const char *typechange_fmt;
1398        const char *added_fmt;
1399        const char *unmerged_fmt;
1400
1401        modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
1402        deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
1403        typechange_fmt = (in_porcelain ? "T\t%s\n" : "%s needs update\n");
1404        added_fmt = (in_porcelain ? "A\t%s\n" : "%s needs update\n");
1405        unmerged_fmt = (in_porcelain ? "U\t%s\n" : "%s: needs merge\n");
1406        for (i = 0; i < istate->cache_nr; i++) {
1407                struct cache_entry *ce, *new;
1408                int cache_errno = 0;
1409                int changed = 0;
1410                int filtered = 0;
1411
1412                ce = istate->cache[i];
1413                if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
1414                        continue;
1415
1416                if (pathspec && !ce_path_match(ce, pathspec, seen))
1417                        filtered = 1;
1418
1419                if (ce_stage(ce)) {
1420                        while ((i < istate->cache_nr) &&
1421                               ! strcmp(istate->cache[i]->name, ce->name))
1422                                i++;
1423                        i--;
1424                        if (allow_unmerged)
1425                                continue;
1426                        if (!filtered)
1427                                show_file(unmerged_fmt, ce->name, in_porcelain,
1428                                          &first, header_msg);
1429                        has_errors = 1;
1430                        continue;
1431                }
1432
1433                if (filtered)
1434                        continue;
1435
1436                new = refresh_cache_ent(istate, ce, options, &cache_errno, &changed);
1437                if (new == ce)
1438                        continue;
1439                if (!new) {
1440                        const char *fmt;
1441
1442                        if (really && cache_errno == EINVAL) {
1443                                /* If we are doing --really-refresh that
1444                                 * means the index is not valid anymore.
1445                                 */
1446                                ce->ce_flags &= ~CE_VALID;
1447                                ce->ce_flags |= CE_UPDATE_IN_BASE;
1448                                mark_fsmonitor_invalid(istate, ce);
1449                                istate->cache_changed |= CE_ENTRY_CHANGED;
1450                        }
1451                        if (quiet)
1452                                continue;
1453
1454                        if (cache_errno == ENOENT)
1455                                fmt = deleted_fmt;
1456                        else if (ce_intent_to_add(ce))
1457                                fmt = added_fmt; /* must be before other checks */
1458                        else if (changed & TYPE_CHANGED)
1459                                fmt = typechange_fmt;
1460                        else
1461                                fmt = modified_fmt;
1462                        show_file(fmt,
1463                                  ce->name, in_porcelain, &first, header_msg);
1464                        has_errors = 1;
1465                        continue;
1466                }
1467
1468                replace_index_entry(istate, i, new);
1469        }
1470        return has_errors;
1471}
1472
1473struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
1474                                               unsigned int options)
1475{
1476        return refresh_cache_ent(&the_index, ce, options, NULL, NULL);
1477}
1478
1479
1480/*****************************************************************
1481 * Index File I/O
1482 *****************************************************************/
1483
1484#define INDEX_FORMAT_DEFAULT 3
1485
1486static unsigned int get_index_format_default(void)
1487{
1488        char *envversion = getenv("GIT_INDEX_VERSION");
1489        char *endp;
1490        int value;
1491        unsigned int version = INDEX_FORMAT_DEFAULT;
1492
1493        if (!envversion) {
1494                if (!git_config_get_int("index.version", &value))
1495                        version = value;
1496                if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1497                        warning(_("index.version set, but the value is invalid.\n"
1498                                  "Using version %i"), INDEX_FORMAT_DEFAULT);
1499                        return INDEX_FORMAT_DEFAULT;
1500                }
1501                return version;
1502        }
1503
1504        version = strtoul(envversion, &endp, 10);
1505        if (*endp ||
1506            version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1507                warning(_("GIT_INDEX_VERSION set, but the value is invalid.\n"
1508                          "Using version %i"), INDEX_FORMAT_DEFAULT);
1509                version = INDEX_FORMAT_DEFAULT;
1510        }
1511        return version;
1512}
1513
1514/*
1515 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
1516 * Again - this is just a (very strong in practice) heuristic that
1517 * the inode hasn't changed.
1518 *
1519 * We save the fields in big-endian order to allow using the
1520 * index file over NFS transparently.
1521 */
1522struct ondisk_cache_entry {
1523        struct cache_time ctime;
1524        struct cache_time mtime;
1525        uint32_t dev;
1526        uint32_t ino;
1527        uint32_t mode;
1528        uint32_t uid;
1529        uint32_t gid;
1530        uint32_t size;
1531        unsigned char sha1[20];
1532        uint16_t flags;
1533        char name[FLEX_ARRAY]; /* more */
1534};
1535
1536/*
1537 * This struct is used when CE_EXTENDED bit is 1
1538 * The struct must match ondisk_cache_entry exactly from
1539 * ctime till flags
1540 */
1541struct ondisk_cache_entry_extended {
1542        struct cache_time ctime;
1543        struct cache_time mtime;
1544        uint32_t dev;
1545        uint32_t ino;
1546        uint32_t mode;
1547        uint32_t uid;
1548        uint32_t gid;
1549        uint32_t size;
1550        unsigned char sha1[20];
1551        uint16_t flags;
1552        uint16_t flags2;
1553        char name[FLEX_ARRAY]; /* more */
1554};
1555
1556/* These are only used for v3 or lower */
1557#define align_padding_size(size, len) ((size + (len) + 8) & ~7) - (size + len)
1558#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
1559#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
1560#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
1561#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
1562                            ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
1563                            ondisk_cache_entry_size(ce_namelen(ce)))
1564
1565/* Allow fsck to force verification of the index checksum. */
1566int verify_index_checksum;
1567
1568/* Allow fsck to force verification of the cache entry order. */
1569int verify_ce_order;
1570
1571static int verify_hdr(struct cache_header *hdr, unsigned long size)
1572{
1573        git_SHA_CTX c;
1574        unsigned char sha1[20];
1575        int hdr_version;
1576
1577        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1578                return error("bad signature");
1579        hdr_version = ntohl(hdr->hdr_version);
1580        if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
1581                return error("bad index version %d", hdr_version);
1582
1583        if (!verify_index_checksum)
1584                return 0;
1585
1586        git_SHA1_Init(&c);
1587        git_SHA1_Update(&c, hdr, size - 20);
1588        git_SHA1_Final(sha1, &c);
1589        if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1590                return error("bad index file sha1 signature");
1591        return 0;
1592}
1593
1594static int read_index_extension(struct index_state *istate,
1595                                const char *ext, void *data, unsigned long sz)
1596{
1597        switch (CACHE_EXT(ext)) {
1598        case CACHE_EXT_TREE:
1599                istate->cache_tree = cache_tree_read(data, sz);
1600                break;
1601        case CACHE_EXT_RESOLVE_UNDO:
1602                istate->resolve_undo = resolve_undo_read(data, sz);
1603                break;
1604        case CACHE_EXT_LINK:
1605                if (read_link_extension(istate, data, sz))
1606                        return -1;
1607                break;
1608        case CACHE_EXT_UNTRACKED:
1609                istate->untracked = read_untracked_extension(data, sz);
1610                break;
1611        case CACHE_EXT_FSMONITOR:
1612                read_fsmonitor_extension(istate, data, sz);
1613                break;
1614        default:
1615                if (*ext < 'A' || 'Z' < *ext)
1616                        return error("index uses %.4s extension, which we do not understand",
1617                                     ext);
1618                fprintf(stderr, "ignoring %.4s extension\n", ext);
1619                break;
1620        }
1621        return 0;
1622}
1623
1624int hold_locked_index(struct lock_file *lk, int lock_flags)
1625{
1626        return hold_lock_file_for_update(lk, get_index_file(), lock_flags);
1627}
1628
1629int read_index(struct index_state *istate)
1630{
1631        return read_index_from(istate, get_index_file(), get_git_dir());
1632}
1633
1634static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
1635                                                   unsigned int flags,
1636                                                   const char *name,
1637                                                   size_t len)
1638{
1639        struct cache_entry *ce = xmalloc(cache_entry_size(len));
1640
1641        ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
1642        ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
1643        ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
1644        ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
1645        ce->ce_stat_data.sd_dev   = get_be32(&ondisk->dev);
1646        ce->ce_stat_data.sd_ino   = get_be32(&ondisk->ino);
1647        ce->ce_mode  = get_be32(&ondisk->mode);
1648        ce->ce_stat_data.sd_uid   = get_be32(&ondisk->uid);
1649        ce->ce_stat_data.sd_gid   = get_be32(&ondisk->gid);
1650        ce->ce_stat_data.sd_size  = get_be32(&ondisk->size);
1651        ce->ce_flags = flags & ~CE_NAMEMASK;
1652        ce->ce_namelen = len;
1653        ce->index = 0;
1654        hashcpy(ce->oid.hash, ondisk->sha1);
1655        memcpy(ce->name, name, len);
1656        ce->name[len] = '\0';
1657        return ce;
1658}
1659
1660/*
1661 * Adjacent cache entries tend to share the leading paths, so it makes
1662 * sense to only store the differences in later entries.  In the v4
1663 * on-disk format of the index, each on-disk cache entry stores the
1664 * number of bytes to be stripped from the end of the previous name,
1665 * and the bytes to append to the result, to come up with its name.
1666 */
1667static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
1668{
1669        const unsigned char *ep, *cp = (const unsigned char *)cp_;
1670        size_t len = decode_varint(&cp);
1671
1672        if (name->len < len)
1673                die("malformed name field in the index");
1674        strbuf_remove(name, name->len - len, len);
1675        for (ep = cp; *ep; ep++)
1676                ; /* find the end */
1677        strbuf_add(name, cp, ep - cp);
1678        return (const char *)ep + 1 - cp_;
1679}
1680
1681static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
1682                                            unsigned long *ent_size,
1683                                            struct strbuf *previous_name)
1684{
1685        struct cache_entry *ce;
1686        size_t len;
1687        const char *name;
1688        unsigned int flags;
1689
1690        /* On-disk flags are just 16 bits */
1691        flags = get_be16(&ondisk->flags);
1692        len = flags & CE_NAMEMASK;
1693
1694        if (flags & CE_EXTENDED) {
1695                struct ondisk_cache_entry_extended *ondisk2;
1696                int extended_flags;
1697                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1698                extended_flags = get_be16(&ondisk2->flags2) << 16;
1699                /* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
1700                if (extended_flags & ~CE_EXTENDED_FLAGS)
1701                        die("Unknown index entry format %08x", extended_flags);
1702                flags |= extended_flags;
1703                name = ondisk2->name;
1704        }
1705        else
1706                name = ondisk->name;
1707
1708        if (!previous_name) {
1709                /* v3 and earlier */
1710                if (len == CE_NAMEMASK)
1711                        len = strlen(name);
1712                ce = cache_entry_from_ondisk(ondisk, flags, name, len);
1713
1714                *ent_size = ondisk_ce_size(ce);
1715        } else {
1716                unsigned long consumed;
1717                consumed = expand_name_field(previous_name, name);
1718                ce = cache_entry_from_ondisk(ondisk, flags,
1719                                             previous_name->buf,
1720                                             previous_name->len);
1721
1722                *ent_size = (name - ((char *)ondisk)) + consumed;
1723        }
1724        return ce;
1725}
1726
1727static void check_ce_order(struct index_state *istate)
1728{
1729        unsigned int i;
1730
1731        if (!verify_ce_order)
1732                return;
1733
1734        for (i = 1; i < istate->cache_nr; i++) {
1735                struct cache_entry *ce = istate->cache[i - 1];
1736                struct cache_entry *next_ce = istate->cache[i];
1737                int name_compare = strcmp(ce->name, next_ce->name);
1738
1739                if (0 < name_compare)
1740                        die("unordered stage entries in index");
1741                if (!name_compare) {
1742                        if (!ce_stage(ce))
1743                                die("multiple stage entries for merged file '%s'",
1744                                    ce->name);
1745                        if (ce_stage(ce) > ce_stage(next_ce))
1746                                die("unordered stage entries for '%s'",
1747                                    ce->name);
1748                }
1749        }
1750}
1751
1752static void tweak_untracked_cache(struct index_state *istate)
1753{
1754        switch (git_config_get_untracked_cache()) {
1755        case -1: /* keep: do nothing */
1756                break;
1757        case 0: /* false */
1758                remove_untracked_cache(istate);
1759                break;
1760        case 1: /* true */
1761                add_untracked_cache(istate);
1762                break;
1763        default: /* unknown value: do nothing */
1764                break;
1765        }
1766}
1767
1768static void tweak_split_index(struct index_state *istate)
1769{
1770        switch (git_config_get_split_index()) {
1771        case -1: /* unset: do nothing */
1772                break;
1773        case 0: /* false */
1774                remove_split_index(istate);
1775                break;
1776        case 1: /* true */
1777                add_split_index(istate);
1778                break;
1779        default: /* unknown value: do nothing */
1780                break;
1781        }
1782}
1783
1784static void post_read_index_from(struct index_state *istate)
1785{
1786        check_ce_order(istate);
1787        tweak_untracked_cache(istate);
1788        tweak_split_index(istate);
1789        tweak_fsmonitor(istate);
1790}
1791
1792/* remember to discard_cache() before reading a different cache! */
1793int do_read_index(struct index_state *istate, const char *path, int must_exist)
1794{
1795        int fd, i;
1796        struct stat st;
1797        unsigned long src_offset;
1798        struct cache_header *hdr;
1799        void *mmap;
1800        size_t mmap_size;
1801        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
1802
1803        if (istate->initialized)
1804                return istate->cache_nr;
1805
1806        istate->timestamp.sec = 0;
1807        istate->timestamp.nsec = 0;
1808        fd = open(path, O_RDONLY);
1809        if (fd < 0) {
1810                if (!must_exist && errno == ENOENT)
1811                        return 0;
1812                die_errno("%s: index file open failed", path);
1813        }
1814
1815        if (fstat(fd, &st))
1816                die_errno("cannot stat the open index");
1817
1818        mmap_size = xsize_t(st.st_size);
1819        if (mmap_size < sizeof(struct cache_header) + 20)
1820                die("index file smaller than expected");
1821
1822        mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
1823        if (mmap == MAP_FAILED)
1824                die_errno("unable to map index file");
1825        close(fd);
1826
1827        hdr = mmap;
1828        if (verify_hdr(hdr, mmap_size) < 0)
1829                goto unmap;
1830
1831        hashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - 20);
1832        istate->version = ntohl(hdr->hdr_version);
1833        istate->cache_nr = ntohl(hdr->hdr_entries);
1834        istate->cache_alloc = alloc_nr(istate->cache_nr);
1835        istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
1836        istate->initialized = 1;
1837
1838        if (istate->version == 4)
1839                previous_name = &previous_name_buf;
1840        else
1841                previous_name = NULL;
1842
1843        src_offset = sizeof(*hdr);
1844        for (i = 0; i < istate->cache_nr; i++) {
1845                struct ondisk_cache_entry *disk_ce;
1846                struct cache_entry *ce;
1847                unsigned long consumed;
1848
1849                disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1850                ce = create_from_disk(disk_ce, &consumed, previous_name);
1851                set_index_entry(istate, i, ce);
1852
1853                src_offset += consumed;
1854        }
1855        strbuf_release(&previous_name_buf);
1856        istate->timestamp.sec = st.st_mtime;
1857        istate->timestamp.nsec = ST_MTIME_NSEC(st);
1858
1859        while (src_offset <= mmap_size - 20 - 8) {
1860                /* After an array of active_nr index entries,
1861                 * there can be arbitrary number of extended
1862                 * sections, each of which is prefixed with
1863                 * extension name (4-byte) and section length
1864                 * in 4-byte network byte order.
1865                 */
1866                uint32_t extsize;
1867                memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1868                extsize = ntohl(extsize);
1869                if (read_index_extension(istate,
1870                                         (const char *) mmap + src_offset,
1871                                         (char *) mmap + src_offset + 8,
1872                                         extsize) < 0)
1873                        goto unmap;
1874                src_offset += 8;
1875                src_offset += extsize;
1876        }
1877        munmap(mmap, mmap_size);
1878        return istate->cache_nr;
1879
1880unmap:
1881        munmap(mmap, mmap_size);
1882        die("index file corrupt");
1883}
1884
1885/*
1886 * Signal that the shared index is used by updating its mtime.
1887 *
1888 * This way, shared index can be removed if they have not been used
1889 * for some time.
1890 */
1891static void freshen_shared_index(const char *shared_index, int warn)
1892{
1893        if (!check_and_freshen_file(shared_index, 1) && warn)
1894                warning("could not freshen shared index '%s'", shared_index);
1895}
1896
1897int read_index_from(struct index_state *istate, const char *path,
1898                    const char *gitdir)
1899{
1900        struct split_index *split_index;
1901        int ret;
1902        char *base_sha1_hex;
1903        char *base_path;
1904
1905        /* istate->initialized covers both .git/index and .git/sharedindex.xxx */
1906        if (istate->initialized)
1907                return istate->cache_nr;
1908
1909        ret = do_read_index(istate, path, 0);
1910
1911        split_index = istate->split_index;
1912        if (!split_index || is_null_sha1(split_index->base_sha1)) {
1913                post_read_index_from(istate);
1914                return ret;
1915        }
1916
1917        if (split_index->base)
1918                discard_index(split_index->base);
1919        else
1920                split_index->base = xcalloc(1, sizeof(*split_index->base));
1921
1922        base_sha1_hex = sha1_to_hex(split_index->base_sha1);
1923        base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_sha1_hex);
1924        ret = do_read_index(split_index->base, base_path, 1);
1925        if (hashcmp(split_index->base_sha1, split_index->base->sha1))
1926                die("broken index, expect %s in %s, got %s",
1927                    base_sha1_hex, base_path,
1928                    sha1_to_hex(split_index->base->sha1));
1929
1930        freshen_shared_index(base_path, 0);
1931        merge_base_index(istate);
1932        post_read_index_from(istate);
1933        free(base_path);
1934        return ret;
1935}
1936
1937int is_index_unborn(struct index_state *istate)
1938{
1939        return (!istate->cache_nr && !istate->timestamp.sec);
1940}
1941
1942int discard_index(struct index_state *istate)
1943{
1944        int i;
1945
1946        for (i = 0; i < istate->cache_nr; i++) {
1947                if (istate->cache[i]->index &&
1948                    istate->split_index &&
1949                    istate->split_index->base &&
1950                    istate->cache[i]->index <= istate->split_index->base->cache_nr &&
1951                    istate->cache[i] == istate->split_index->base->cache[istate->cache[i]->index - 1])
1952                        continue;
1953                free(istate->cache[i]);
1954        }
1955        resolve_undo_clear_index(istate);
1956        istate->cache_nr = 0;
1957        istate->cache_changed = 0;
1958        istate->timestamp.sec = 0;
1959        istate->timestamp.nsec = 0;
1960        free_name_hash(istate);
1961        cache_tree_free(&(istate->cache_tree));
1962        istate->initialized = 0;
1963        FREE_AND_NULL(istate->cache);
1964        istate->cache_alloc = 0;
1965        discard_split_index(istate);
1966        free_untracked_cache(istate->untracked);
1967        istate->untracked = NULL;
1968        return 0;
1969}
1970
1971int unmerged_index(const struct index_state *istate)
1972{
1973        int i;
1974        for (i = 0; i < istate->cache_nr; i++) {
1975                if (ce_stage(istate->cache[i]))
1976                        return 1;
1977        }
1978        return 0;
1979}
1980
1981#define WRITE_BUFFER_SIZE 8192
1982static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1983static unsigned long write_buffer_len;
1984
1985static int ce_write_flush(git_SHA_CTX *context, int fd)
1986{
1987        unsigned int buffered = write_buffer_len;
1988        if (buffered) {
1989                git_SHA1_Update(context, write_buffer, buffered);
1990                if (write_in_full(fd, write_buffer, buffered) < 0)
1991                        return -1;
1992                write_buffer_len = 0;
1993        }
1994        return 0;
1995}
1996
1997static int ce_write(git_SHA_CTX *context, int fd, void *data, unsigned int len)
1998{
1999        while (len) {
2000                unsigned int buffered = write_buffer_len;
2001                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
2002                if (partial > len)
2003                        partial = len;
2004                memcpy(write_buffer + buffered, data, partial);
2005                buffered += partial;
2006                if (buffered == WRITE_BUFFER_SIZE) {
2007                        write_buffer_len = buffered;
2008                        if (ce_write_flush(context, fd))
2009                                return -1;
2010                        buffered = 0;
2011                }
2012                write_buffer_len = buffered;
2013                len -= partial;
2014                data = (char *) data + partial;
2015        }
2016        return 0;
2017}
2018
2019static int write_index_ext_header(git_SHA_CTX *context, int fd,
2020                                  unsigned int ext, unsigned int sz)
2021{
2022        ext = htonl(ext);
2023        sz = htonl(sz);
2024        return ((ce_write(context, fd, &ext, 4) < 0) ||
2025                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
2026}
2027
2028static int ce_flush(git_SHA_CTX *context, int fd, unsigned char *sha1)
2029{
2030        unsigned int left = write_buffer_len;
2031
2032        if (left) {
2033                write_buffer_len = 0;
2034                git_SHA1_Update(context, write_buffer, left);
2035        }
2036
2037        /* Flush first if not enough space for SHA1 signature */
2038        if (left + 20 > WRITE_BUFFER_SIZE) {
2039                if (write_in_full(fd, write_buffer, left) < 0)
2040                        return -1;
2041                left = 0;
2042        }
2043
2044        /* Append the SHA1 signature at the end */
2045        git_SHA1_Final(write_buffer + left, context);
2046        hashcpy(sha1, write_buffer + left);
2047        left += 20;
2048        return (write_in_full(fd, write_buffer, left) < 0) ? -1 : 0;
2049}
2050
2051static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
2052{
2053        /*
2054         * The only thing we care about in this function is to smudge the
2055         * falsely clean entry due to touch-update-touch race, so we leave
2056         * everything else as they are.  We are called for entries whose
2057         * ce_stat_data.sd_mtime match the index file mtime.
2058         *
2059         * Note that this actually does not do much for gitlinks, for
2060         * which ce_match_stat_basic() always goes to the actual
2061         * contents.  The caller checks with is_racy_timestamp() which
2062         * always says "no" for gitlinks, so we are not called for them ;-)
2063         */
2064        struct stat st;
2065
2066        if (lstat(ce->name, &st) < 0)
2067                return;
2068        if (ce_match_stat_basic(ce, &st))
2069                return;
2070        if (ce_modified_check_fs(ce, &st)) {
2071                /* This is "racily clean"; smudge it.  Note that this
2072                 * is a tricky code.  At first glance, it may appear
2073                 * that it can break with this sequence:
2074                 *
2075                 * $ echo xyzzy >frotz
2076                 * $ git-update-index --add frotz
2077                 * $ : >frotz
2078                 * $ sleep 3
2079                 * $ echo filfre >nitfol
2080                 * $ git-update-index --add nitfol
2081                 *
2082                 * but it does not.  When the second update-index runs,
2083                 * it notices that the entry "frotz" has the same timestamp
2084                 * as index, and if we were to smudge it by resetting its
2085                 * size to zero here, then the object name recorded
2086                 * in index is the 6-byte file but the cached stat information
2087                 * becomes zero --- which would then match what we would
2088                 * obtain from the filesystem next time we stat("frotz").
2089                 *
2090                 * However, the second update-index, before calling
2091                 * this function, notices that the cached size is 6
2092                 * bytes and what is on the filesystem is an empty
2093                 * file, and never calls us, so the cached size information
2094                 * for "frotz" stays 6 which does not match the filesystem.
2095                 */
2096                ce->ce_stat_data.sd_size = 0;
2097        }
2098}
2099
2100/* Copy miscellaneous fields but not the name */
2101static void copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
2102                                       struct cache_entry *ce)
2103{
2104        short flags;
2105
2106        ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec);
2107        ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec);
2108        ondisk->ctime.nsec = htonl(ce->ce_stat_data.sd_ctime.nsec);
2109        ondisk->mtime.nsec = htonl(ce->ce_stat_data.sd_mtime.nsec);
2110        ondisk->dev  = htonl(ce->ce_stat_data.sd_dev);
2111        ondisk->ino  = htonl(ce->ce_stat_data.sd_ino);
2112        ondisk->mode = htonl(ce->ce_mode);
2113        ondisk->uid  = htonl(ce->ce_stat_data.sd_uid);
2114        ondisk->gid  = htonl(ce->ce_stat_data.sd_gid);
2115        ondisk->size = htonl(ce->ce_stat_data.sd_size);
2116        hashcpy(ondisk->sha1, ce->oid.hash);
2117
2118        flags = ce->ce_flags & ~CE_NAMEMASK;
2119        flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
2120        ondisk->flags = htons(flags);
2121        if (ce->ce_flags & CE_EXTENDED) {
2122                struct ondisk_cache_entry_extended *ondisk2;
2123                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
2124                ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
2125        }
2126}
2127
2128static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
2129                          struct strbuf *previous_name, struct ondisk_cache_entry *ondisk)
2130{
2131        int size;
2132        int saved_namelen = saved_namelen; /* compiler workaround */
2133        int result;
2134        static unsigned char padding[8] = { 0x00 };
2135
2136        if (ce->ce_flags & CE_STRIP_NAME) {
2137                saved_namelen = ce_namelen(ce);
2138                ce->ce_namelen = 0;
2139        }
2140
2141        if (ce->ce_flags & CE_EXTENDED)
2142                size = offsetof(struct ondisk_cache_entry_extended, name);
2143        else
2144                size = offsetof(struct ondisk_cache_entry, name);
2145
2146        if (!previous_name) {
2147                int len = ce_namelen(ce);
2148                copy_cache_entry_to_ondisk(ondisk, ce);
2149                result = ce_write(c, fd, ondisk, size);
2150                if (!result)
2151                        result = ce_write(c, fd, ce->name, len);
2152                if (!result)
2153                        result = ce_write(c, fd, padding, align_padding_size(size, len));
2154        } else {
2155                int common, to_remove, prefix_size;
2156                unsigned char to_remove_vi[16];
2157                for (common = 0;
2158                     (ce->name[common] &&
2159                      common < previous_name->len &&
2160                      ce->name[common] == previous_name->buf[common]);
2161                     common++)
2162                        ; /* still matching */
2163                to_remove = previous_name->len - common;
2164                prefix_size = encode_varint(to_remove, to_remove_vi);
2165
2166                copy_cache_entry_to_ondisk(ondisk, ce);
2167                result = ce_write(c, fd, ondisk, size);
2168                if (!result)
2169                        result = ce_write(c, fd, to_remove_vi, prefix_size);
2170                if (!result)
2171                        result = ce_write(c, fd, ce->name + common, ce_namelen(ce) - common);
2172                if (!result)
2173                        result = ce_write(c, fd, padding, 1);
2174
2175                strbuf_splice(previous_name, common, to_remove,
2176                              ce->name + common, ce_namelen(ce) - common);
2177        }
2178        if (ce->ce_flags & CE_STRIP_NAME) {
2179                ce->ce_namelen = saved_namelen;
2180                ce->ce_flags &= ~CE_STRIP_NAME;
2181        }
2182
2183        return result;
2184}
2185
2186/*
2187 * This function verifies if index_state has the correct sha1 of the
2188 * index file.  Don't die if we have any other failure, just return 0.
2189 */
2190static int verify_index_from(const struct index_state *istate, const char *path)
2191{
2192        int fd;
2193        ssize_t n;
2194        struct stat st;
2195        unsigned char sha1[20];
2196
2197        if (!istate->initialized)
2198                return 0;
2199
2200        fd = open(path, O_RDONLY);
2201        if (fd < 0)
2202                return 0;
2203
2204        if (fstat(fd, &st))
2205                goto out;
2206
2207        if (st.st_size < sizeof(struct cache_header) + 20)
2208                goto out;
2209
2210        n = pread_in_full(fd, sha1, 20, st.st_size - 20);
2211        if (n != 20)
2212                goto out;
2213
2214        if (hashcmp(istate->sha1, sha1))
2215                goto out;
2216
2217        close(fd);
2218        return 1;
2219
2220out:
2221        close(fd);
2222        return 0;
2223}
2224
2225static int verify_index(const struct index_state *istate)
2226{
2227        return verify_index_from(istate, get_index_file());
2228}
2229
2230static int has_racy_timestamp(struct index_state *istate)
2231{
2232        int entries = istate->cache_nr;
2233        int i;
2234
2235        for (i = 0; i < entries; i++) {
2236                struct cache_entry *ce = istate->cache[i];
2237                if (is_racy_timestamp(istate, ce))
2238                        return 1;
2239        }
2240        return 0;
2241}
2242
2243void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
2244{
2245        if ((istate->cache_changed || has_racy_timestamp(istate)) &&
2246            verify_index(istate))
2247                write_locked_index(istate, lockfile, COMMIT_LOCK);
2248        else
2249                rollback_lock_file(lockfile);
2250}
2251
2252/*
2253 * On success, `tempfile` is closed. If it is the temporary file
2254 * of a `struct lock_file`, we will therefore effectively perform
2255 * a 'close_lock_file_gently()`. Since that is an implementation
2256 * detail of lockfiles, callers of `do_write_index()` should not
2257 * rely on it.
2258 */
2259static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
2260                          int strip_extensions)
2261{
2262        int newfd = tempfile->fd;
2263        git_SHA_CTX c;
2264        struct cache_header hdr;
2265        int i, err = 0, removed, extended, hdr_version;
2266        struct cache_entry **cache = istate->cache;
2267        int entries = istate->cache_nr;
2268        struct stat st;
2269        struct ondisk_cache_entry_extended ondisk;
2270        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
2271        int drop_cache_tree = istate->drop_cache_tree;
2272
2273        for (i = removed = extended = 0; i < entries; i++) {
2274                if (cache[i]->ce_flags & CE_REMOVE)
2275                        removed++;
2276
2277                /* reduce extended entries if possible */
2278                cache[i]->ce_flags &= ~CE_EXTENDED;
2279                if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) {
2280                        extended++;
2281                        cache[i]->ce_flags |= CE_EXTENDED;
2282                }
2283        }
2284
2285        if (!istate->version) {
2286                istate->version = get_index_format_default();
2287                if (getenv("GIT_TEST_SPLIT_INDEX"))
2288                        init_split_index(istate);
2289        }
2290
2291        /* demote version 3 to version 2 when the latter suffices */
2292        if (istate->version == 3 || istate->version == 2)
2293                istate->version = extended ? 3 : 2;
2294
2295        hdr_version = istate->version;
2296
2297        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
2298        hdr.hdr_version = htonl(hdr_version);
2299        hdr.hdr_entries = htonl(entries - removed);
2300
2301        git_SHA1_Init(&c);
2302        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
2303                return -1;
2304
2305        previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
2306
2307        for (i = 0; i < entries; i++) {
2308                struct cache_entry *ce = cache[i];
2309                if (ce->ce_flags & CE_REMOVE)
2310                        continue;
2311                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
2312                        ce_smudge_racily_clean_entry(ce);
2313                if (is_null_oid(&ce->oid)) {
2314                        static const char msg[] = "cache entry has null sha1: %s";
2315                        static int allow = -1;
2316
2317                        if (allow < 0)
2318                                allow = git_env_bool("GIT_ALLOW_NULL_SHA1", 0);
2319                        if (allow)
2320                                warning(msg, ce->name);
2321                        else
2322                                err = error(msg, ce->name);
2323
2324                        drop_cache_tree = 1;
2325                }
2326                if (ce_write_entry(&c, newfd, ce, previous_name, (struct ondisk_cache_entry *)&ondisk) < 0)
2327                        err = -1;
2328
2329                if (err)
2330                        break;
2331        }
2332        strbuf_release(&previous_name_buf);
2333
2334        if (err)
2335                return err;
2336
2337        /* Write extension data here */
2338        if (!strip_extensions && istate->split_index) {
2339                struct strbuf sb = STRBUF_INIT;
2340
2341                err = write_link_extension(&sb, istate) < 0 ||
2342                        write_index_ext_header(&c, newfd, CACHE_EXT_LINK,
2343                                               sb.len) < 0 ||
2344                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2345                strbuf_release(&sb);
2346                if (err)
2347                        return -1;
2348        }
2349        if (!strip_extensions && !drop_cache_tree && istate->cache_tree) {
2350                struct strbuf sb = STRBUF_INIT;
2351
2352                cache_tree_write(&sb, istate->cache_tree);
2353                err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
2354                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2355                strbuf_release(&sb);
2356                if (err)
2357                        return -1;
2358        }
2359        if (!strip_extensions && istate->resolve_undo) {
2360                struct strbuf sb = STRBUF_INIT;
2361
2362                resolve_undo_write(&sb, istate->resolve_undo);
2363                err = write_index_ext_header(&c, newfd, CACHE_EXT_RESOLVE_UNDO,
2364                                             sb.len) < 0
2365                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2366                strbuf_release(&sb);
2367                if (err)
2368                        return -1;
2369        }
2370        if (!strip_extensions && istate->untracked) {
2371                struct strbuf sb = STRBUF_INIT;
2372
2373                write_untracked_extension(&sb, istate->untracked);
2374                err = write_index_ext_header(&c, newfd, CACHE_EXT_UNTRACKED,
2375                                             sb.len) < 0 ||
2376                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2377                strbuf_release(&sb);
2378                if (err)
2379                        return -1;
2380        }
2381        if (!strip_extensions && istate->fsmonitor_last_update) {
2382                struct strbuf sb = STRBUF_INIT;
2383
2384                write_fsmonitor_extension(&sb, istate);
2385                err = write_index_ext_header(&c, newfd, CACHE_EXT_FSMONITOR, sb.len) < 0
2386                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2387                strbuf_release(&sb);
2388                if (err)
2389                        return -1;
2390        }
2391
2392        if (ce_flush(&c, newfd, istate->sha1))
2393                return -1;
2394        if (close_tempfile_gently(tempfile)) {
2395                error(_("could not close '%s'"), tempfile->filename.buf);
2396                return -1;
2397        }
2398        if (stat(tempfile->filename.buf, &st))
2399                return -1;
2400        istate->timestamp.sec = (unsigned int)st.st_mtime;
2401        istate->timestamp.nsec = ST_MTIME_NSEC(st);
2402        return 0;
2403}
2404
2405void set_alternate_index_output(const char *name)
2406{
2407        alternate_index_output = name;
2408}
2409
2410static int commit_locked_index(struct lock_file *lk)
2411{
2412        if (alternate_index_output)
2413                return commit_lock_file_to(lk, alternate_index_output);
2414        else
2415                return commit_lock_file(lk);
2416}
2417
2418static int do_write_locked_index(struct index_state *istate, struct lock_file *lock,
2419                                 unsigned flags)
2420{
2421        int ret = do_write_index(istate, lock->tempfile, 0);
2422        if (ret)
2423                return ret;
2424        if (flags & COMMIT_LOCK)
2425                return commit_locked_index(lock);
2426        return close_lock_file_gently(lock);
2427}
2428
2429static int write_split_index(struct index_state *istate,
2430                             struct lock_file *lock,
2431                             unsigned flags)
2432{
2433        int ret;
2434        prepare_to_write_split_index(istate);
2435        ret = do_write_locked_index(istate, lock, flags);
2436        finish_writing_split_index(istate);
2437        return ret;
2438}
2439
2440static const char *shared_index_expire = "2.weeks.ago";
2441
2442static unsigned long get_shared_index_expire_date(void)
2443{
2444        static unsigned long shared_index_expire_date;
2445        static int shared_index_expire_date_prepared;
2446
2447        if (!shared_index_expire_date_prepared) {
2448                git_config_get_expiry("splitindex.sharedindexexpire",
2449                                      &shared_index_expire);
2450                shared_index_expire_date = approxidate(shared_index_expire);
2451                shared_index_expire_date_prepared = 1;
2452        }
2453
2454        return shared_index_expire_date;
2455}
2456
2457static int should_delete_shared_index(const char *shared_index_path)
2458{
2459        struct stat st;
2460        unsigned long expiration;
2461
2462        /* Check timestamp */
2463        expiration = get_shared_index_expire_date();
2464        if (!expiration)
2465                return 0;
2466        if (stat(shared_index_path, &st))
2467                return error_errno(_("could not stat '%s'"), shared_index_path);
2468        if (st.st_mtime > expiration)
2469                return 0;
2470
2471        return 1;
2472}
2473
2474static int clean_shared_index_files(const char *current_hex)
2475{
2476        struct dirent *de;
2477        DIR *dir = opendir(get_git_dir());
2478
2479        if (!dir)
2480                return error_errno(_("unable to open git dir: %s"), get_git_dir());
2481
2482        while ((de = readdir(dir)) != NULL) {
2483                const char *sha1_hex;
2484                const char *shared_index_path;
2485                if (!skip_prefix(de->d_name, "sharedindex.", &sha1_hex))
2486                        continue;
2487                if (!strcmp(sha1_hex, current_hex))
2488                        continue;
2489                shared_index_path = git_path("%s", de->d_name);
2490                if (should_delete_shared_index(shared_index_path) > 0 &&
2491                    unlink(shared_index_path))
2492                        warning_errno(_("unable to unlink: %s"), shared_index_path);
2493        }
2494        closedir(dir);
2495
2496        return 0;
2497}
2498
2499static int write_shared_index(struct index_state *istate,
2500                              struct tempfile **temp)
2501{
2502        struct split_index *si = istate->split_index;
2503        int ret;
2504
2505        move_cache_to_base_index(istate);
2506        ret = do_write_index(si->base, *temp, 1);
2507        if (ret)
2508                return ret;
2509        ret = adjust_shared_perm(get_tempfile_path(*temp));
2510        if (ret) {
2511                error("cannot fix permission bits on %s", get_tempfile_path(*temp));
2512                return ret;
2513        }
2514        ret = rename_tempfile(temp,
2515                              git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
2516        if (!ret) {
2517                hashcpy(si->base_sha1, si->base->sha1);
2518                clean_shared_index_files(sha1_to_hex(si->base->sha1));
2519        }
2520
2521        return ret;
2522}
2523
2524static const int default_max_percent_split_change = 20;
2525
2526static int too_many_not_shared_entries(struct index_state *istate)
2527{
2528        int i, not_shared = 0;
2529        int max_split = git_config_get_max_percent_split_change();
2530
2531        switch (max_split) {
2532        case -1:
2533                /* not or badly configured: use the default value */
2534                max_split = default_max_percent_split_change;
2535                break;
2536        case 0:
2537                return 1; /* 0% means always write a new shared index */
2538        case 100:
2539                return 0; /* 100% means never write a new shared index */
2540        default:
2541                break; /* just use the configured value */
2542        }
2543
2544        /* Count not shared entries */
2545        for (i = 0; i < istate->cache_nr; i++) {
2546                struct cache_entry *ce = istate->cache[i];
2547                if (!ce->index)
2548                        not_shared++;
2549        }
2550
2551        return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100;
2552}
2553
2554int write_locked_index(struct index_state *istate, struct lock_file *lock,
2555                       unsigned flags)
2556{
2557        int new_shared_index, ret;
2558        struct split_index *si = istate->split_index;
2559
2560        if (istate->fsmonitor_last_update)
2561                fill_fsmonitor_bitmap(istate);
2562
2563        if (!si || alternate_index_output ||
2564            (istate->cache_changed & ~EXTMASK)) {
2565                if (si)
2566                        hashclr(si->base_sha1);
2567                ret = do_write_locked_index(istate, lock, flags);
2568                goto out;
2569        }
2570
2571        if (getenv("GIT_TEST_SPLIT_INDEX")) {
2572                int v = si->base_sha1[0];
2573                if ((v & 15) < 6)
2574                        istate->cache_changed |= SPLIT_INDEX_ORDERED;
2575        }
2576        if (too_many_not_shared_entries(istate))
2577                istate->cache_changed |= SPLIT_INDEX_ORDERED;
2578
2579        new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED;
2580
2581        if (new_shared_index) {
2582                struct tempfile *temp;
2583                int saved_errno;
2584
2585                temp = mks_tempfile(git_path("sharedindex_XXXXXX"));
2586                if (!temp) {
2587                        hashclr(si->base_sha1);
2588                        ret = do_write_locked_index(istate, lock, flags);
2589                        goto out;
2590                }
2591                ret = write_shared_index(istate, &temp);
2592
2593                saved_errno = errno;
2594                if (is_tempfile_active(temp))
2595                        delete_tempfile(&temp);
2596                errno = saved_errno;
2597
2598                if (ret)
2599                        goto out;
2600        }
2601
2602        ret = write_split_index(istate, lock, flags);
2603
2604        /* Freshen the shared index only if the split-index was written */
2605        if (!ret && !new_shared_index) {
2606                const char *shared_index = git_path("sharedindex.%s",
2607                                                    sha1_to_hex(si->base_sha1));
2608                freshen_shared_index(shared_index, 1);
2609        }
2610
2611out:
2612        if (flags & COMMIT_LOCK)
2613                rollback_lock_file(lock);
2614        return ret;
2615}
2616
2617/*
2618 * Read the index file that is potentially unmerged into given
2619 * index_state, dropping any unmerged entries.  Returns true if
2620 * the index is unmerged.  Callers who want to refuse to work
2621 * from an unmerged state can call this and check its return value,
2622 * instead of calling read_cache().
2623 */
2624int read_index_unmerged(struct index_state *istate)
2625{
2626        int i;
2627        int unmerged = 0;
2628
2629        read_index(istate);
2630        for (i = 0; i < istate->cache_nr; i++) {
2631                struct cache_entry *ce = istate->cache[i];
2632                struct cache_entry *new_ce;
2633                int size, len;
2634
2635                if (!ce_stage(ce))
2636                        continue;
2637                unmerged = 1;
2638                len = ce_namelen(ce);
2639                size = cache_entry_size(len);
2640                new_ce = xcalloc(1, size);
2641                memcpy(new_ce->name, ce->name, len);
2642                new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED;
2643                new_ce->ce_namelen = len;
2644                new_ce->ce_mode = ce->ce_mode;
2645                if (add_index_entry(istate, new_ce, 0))
2646                        return error("%s: cannot drop to stage #0",
2647                                     new_ce->name);
2648        }
2649        return unmerged;
2650}
2651
2652/*
2653 * Returns 1 if the path is an "other" path with respect to
2654 * the index; that is, the path is not mentioned in the index at all,
2655 * either as a file, a directory with some files in the index,
2656 * or as an unmerged entry.
2657 *
2658 * We helpfully remove a trailing "/" from directories so that
2659 * the output of read_directory can be used as-is.
2660 */
2661int index_name_is_other(const struct index_state *istate, const char *name,
2662                int namelen)
2663{
2664        int pos;
2665        if (namelen && name[namelen - 1] == '/')
2666                namelen--;
2667        pos = index_name_pos(istate, name, namelen);
2668        if (0 <= pos)
2669                return 0;       /* exact match */
2670        pos = -pos - 1;
2671        if (pos < istate->cache_nr) {
2672                struct cache_entry *ce = istate->cache[pos];
2673                if (ce_namelen(ce) == namelen &&
2674                    !memcmp(ce->name, name, namelen))
2675                        return 0; /* Yup, this one exists unmerged */
2676        }
2677        return 1;
2678}
2679
2680void *read_blob_data_from_index(const struct index_state *istate,
2681                                const char *path, unsigned long *size)
2682{
2683        int pos, len;
2684        unsigned long sz;
2685        enum object_type type;
2686        void *data;
2687
2688        len = strlen(path);
2689        pos = index_name_pos(istate, path, len);
2690        if (pos < 0) {
2691                /*
2692                 * We might be in the middle of a merge, in which
2693                 * case we would read stage #2 (ours).
2694                 */
2695                int i;
2696                for (i = -pos - 1;
2697                     (pos < 0 && i < istate->cache_nr &&
2698                      !strcmp(istate->cache[i]->name, path));
2699                     i++)
2700                        if (ce_stage(istate->cache[i]) == 2)
2701                                pos = i;
2702        }
2703        if (pos < 0)
2704                return NULL;
2705        data = read_sha1_file(istate->cache[pos]->oid.hash, &type, &sz);
2706        if (!data || type != OBJ_BLOB) {
2707                free(data);
2708                return NULL;
2709        }
2710        if (size)
2711                *size = sz;
2712        return data;
2713}
2714
2715void stat_validity_clear(struct stat_validity *sv)
2716{
2717        FREE_AND_NULL(sv->sd);
2718}
2719
2720int stat_validity_check(struct stat_validity *sv, const char *path)
2721{
2722        struct stat st;
2723
2724        if (stat(path, &st) < 0)
2725                return sv->sd == NULL;
2726        if (!sv->sd)
2727                return 0;
2728        return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
2729}
2730
2731void stat_validity_update(struct stat_validity *sv, int fd)
2732{
2733        struct stat st;
2734
2735        if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
2736                stat_validity_clear(sv);
2737        else {
2738                if (!sv->sd)
2739                        sv->sd = xcalloc(1, sizeof(struct stat_data));
2740                fill_stat_data(sv->sd, &st);
2741        }
2742}
2743
2744void move_index_extensions(struct index_state *dst, struct index_state *src)
2745{
2746        dst->untracked = src->untracked;
2747        src->untracked = NULL;
2748}