read-cache.con commit Merge branch 'sg/revision-parser-skip-prefix' (e77d58a)
   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 "tempfile.h"
   9#include "lockfile.h"
  10#include "cache-tree.h"
  11#include "refs.h"
  12#include "dir.h"
  13#include "tree.h"
  14#include "commit.h"
  15#include "blob.h"
  16#include "resolve-undo.h"
  17#include "strbuf.h"
  18#include "varint.h"
  19#include "split-index.h"
  20#include "utf8.h"
  21
  22/* Mask for the name length in ce_flags in the on-disk index */
  23
  24#define CE_NAMEMASK  (0x0fff)
  25
  26/* Index extensions.
  27 *
  28 * The first letter should be 'A'..'Z' for extensions that are not
  29 * necessary for a correct operation (i.e. optimization data).
  30 * When new extensions are added that _needs_ to be understood in
  31 * order to correctly interpret the index file, pick character that
  32 * is outside the range, to cause the reader to abort.
  33 */
  34
  35#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  36#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  37#define CACHE_EXT_RESOLVE_UNDO 0x52455543 /* "REUC" */
  38#define CACHE_EXT_LINK 0x6c696e6b         /* "link" */
  39#define CACHE_EXT_UNTRACKED 0x554E5452    /* "UNTR" */
  40
  41/* changes that can be kept in $GIT_DIR/index (basically all extensions) */
  42#define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \
  43                 CE_ENTRY_ADDED | CE_ENTRY_REMOVED | CE_ENTRY_CHANGED | \
  44                 SPLIT_INDEX_ORDERED | UNTRACKED_CHANGED)
  45
  46struct index_state the_index;
  47static const char *alternate_index_output;
  48
  49static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  50{
  51        istate->cache[nr] = ce;
  52        add_name_hash(istate, ce);
  53}
  54
  55static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  56{
  57        struct cache_entry *old = istate->cache[nr];
  58
  59        replace_index_entry_in_base(istate, old, ce);
  60        remove_name_hash(istate, old);
  61        free(old);
  62        set_index_entry(istate, nr, ce);
  63        ce->ce_flags |= CE_UPDATE_IN_BASE;
  64        istate->cache_changed |= CE_ENTRY_CHANGED;
  65}
  66
  67void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
  68{
  69        struct cache_entry *old = istate->cache[nr], *new;
  70        int namelen = strlen(new_name);
  71
  72        new = xmalloc(cache_entry_size(namelen));
  73        copy_cache_entry(new, old);
  74        new->ce_flags &= ~CE_HASHED;
  75        new->ce_namelen = namelen;
  76        new->index = 0;
  77        memcpy(new->name, new_name, namelen + 1);
  78
  79        cache_tree_invalidate_path(istate, old->name);
  80        untracked_cache_remove_from_index(istate, old->name);
  81        remove_index_entry_at(istate, nr);
  82        add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
  83}
  84
  85void fill_stat_data(struct stat_data *sd, struct stat *st)
  86{
  87        sd->sd_ctime.sec = (unsigned int)st->st_ctime;
  88        sd->sd_mtime.sec = (unsigned int)st->st_mtime;
  89        sd->sd_ctime.nsec = ST_CTIME_NSEC(*st);
  90        sd->sd_mtime.nsec = ST_MTIME_NSEC(*st);
  91        sd->sd_dev = st->st_dev;
  92        sd->sd_ino = st->st_ino;
  93        sd->sd_uid = st->st_uid;
  94        sd->sd_gid = st->st_gid;
  95        sd->sd_size = st->st_size;
  96}
  97
  98int match_stat_data(const struct stat_data *sd, struct stat *st)
  99{
 100        int changed = 0;
 101
 102        if (sd->sd_mtime.sec != (unsigned int)st->st_mtime)
 103                changed |= MTIME_CHANGED;
 104        if (trust_ctime && check_stat &&
 105            sd->sd_ctime.sec != (unsigned int)st->st_ctime)
 106                changed |= CTIME_CHANGED;
 107
 108#ifdef USE_NSEC
 109        if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st))
 110                changed |= MTIME_CHANGED;
 111        if (trust_ctime && check_stat &&
 112            sd->sd_ctime.nsec != ST_CTIME_NSEC(*st))
 113                changed |= CTIME_CHANGED;
 114#endif
 115
 116        if (check_stat) {
 117                if (sd->sd_uid != (unsigned int) st->st_uid ||
 118                        sd->sd_gid != (unsigned int) st->st_gid)
 119                        changed |= OWNER_CHANGED;
 120                if (sd->sd_ino != (unsigned int) st->st_ino)
 121                        changed |= INODE_CHANGED;
 122        }
 123
 124#ifdef USE_STDEV
 125        /*
 126         * st_dev breaks on network filesystems where different
 127         * clients will have different views of what "device"
 128         * the filesystem is on
 129         */
 130        if (check_stat && sd->sd_dev != (unsigned int) st->st_dev)
 131                        changed |= INODE_CHANGED;
 132#endif
 133
 134        if (sd->sd_size != (unsigned int) st->st_size)
 135                changed |= DATA_CHANGED;
 136
 137        return changed;
 138}
 139
 140/*
 141 * This only updates the "non-critical" parts of the directory
 142 * cache, ie the parts that aren't tracked by GIT, and only used
 143 * to validate the cache.
 144 */
 145void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
 146{
 147        fill_stat_data(&ce->ce_stat_data, st);
 148
 149        if (assume_unchanged)
 150                ce->ce_flags |= CE_VALID;
 151
 152        if (S_ISREG(st->st_mode))
 153                ce_mark_uptodate(ce);
 154}
 155
 156static int ce_compare_data(const struct cache_entry *ce, struct stat *st)
 157{
 158        int match = -1;
 159        int fd = git_open_cloexec(ce->name, O_RDONLY);
 160
 161        if (fd >= 0) {
 162                unsigned char sha1[20];
 163                if (!index_fd(sha1, fd, st, OBJ_BLOB, ce->name, 0))
 164                        match = hashcmp(sha1, ce->oid.hash);
 165                /* index_fd() closed the file descriptor already */
 166        }
 167        return match;
 168}
 169
 170static int ce_compare_link(const struct cache_entry *ce, size_t expected_size)
 171{
 172        int match = -1;
 173        void *buffer;
 174        unsigned long size;
 175        enum object_type type;
 176        struct strbuf sb = STRBUF_INIT;
 177
 178        if (strbuf_readlink(&sb, ce->name, expected_size))
 179                return -1;
 180
 181        buffer = read_sha1_file(ce->oid.hash, &type, &size);
 182        if (buffer) {
 183                if (size == sb.len)
 184                        match = memcmp(buffer, sb.buf, size);
 185                free(buffer);
 186        }
 187        strbuf_release(&sb);
 188        return match;
 189}
 190
 191static int ce_compare_gitlink(const struct cache_entry *ce)
 192{
 193        unsigned char sha1[20];
 194
 195        /*
 196         * We don't actually require that the .git directory
 197         * under GITLINK directory be a valid git directory. It
 198         * might even be missing (in case nobody populated that
 199         * sub-project).
 200         *
 201         * If so, we consider it always to match.
 202         */
 203        if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 204                return 0;
 205        return hashcmp(sha1, ce->oid.hash);
 206}
 207
 208static int ce_modified_check_fs(const struct cache_entry *ce, struct stat *st)
 209{
 210        switch (st->st_mode & S_IFMT) {
 211        case S_IFREG:
 212                if (ce_compare_data(ce, st))
 213                        return DATA_CHANGED;
 214                break;
 215        case S_IFLNK:
 216                if (ce_compare_link(ce, xsize_t(st->st_size)))
 217                        return DATA_CHANGED;
 218                break;
 219        case S_IFDIR:
 220                if (S_ISGITLINK(ce->ce_mode))
 221                        return ce_compare_gitlink(ce) ? DATA_CHANGED : 0;
 222        default:
 223                return TYPE_CHANGED;
 224        }
 225        return 0;
 226}
 227
 228static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st)
 229{
 230        unsigned int changed = 0;
 231
 232        if (ce->ce_flags & CE_REMOVE)
 233                return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 234
 235        switch (ce->ce_mode & S_IFMT) {
 236        case S_IFREG:
 237                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 238                /* We consider only the owner x bit to be relevant for
 239                 * "mode changes"
 240                 */
 241                if (trust_executable_bit &&
 242                    (0100 & (ce->ce_mode ^ st->st_mode)))
 243                        changed |= MODE_CHANGED;
 244                break;
 245        case S_IFLNK:
 246                if (!S_ISLNK(st->st_mode) &&
 247                    (has_symlinks || !S_ISREG(st->st_mode)))
 248                        changed |= TYPE_CHANGED;
 249                break;
 250        case S_IFGITLINK:
 251                /* We ignore most of the st_xxx fields for gitlinks */
 252                if (!S_ISDIR(st->st_mode))
 253                        changed |= TYPE_CHANGED;
 254                else if (ce_compare_gitlink(ce))
 255                        changed |= DATA_CHANGED;
 256                return changed;
 257        default:
 258                die("internal error: ce_mode is %o", ce->ce_mode);
 259        }
 260
 261        changed |= match_stat_data(&ce->ce_stat_data, st);
 262
 263        /* Racily smudged entry? */
 264        if (!ce->ce_stat_data.sd_size) {
 265                if (!is_empty_blob_sha1(ce->oid.hash))
 266                        changed |= DATA_CHANGED;
 267        }
 268
 269        return changed;
 270}
 271
 272static int is_racy_stat(const struct index_state *istate,
 273                        const struct stat_data *sd)
 274{
 275        return (istate->timestamp.sec &&
 276#ifdef USE_NSEC
 277                 /* nanosecond timestamped files can also be racy! */
 278                (istate->timestamp.sec < sd->sd_mtime.sec ||
 279                 (istate->timestamp.sec == sd->sd_mtime.sec &&
 280                  istate->timestamp.nsec <= sd->sd_mtime.nsec))
 281#else
 282                istate->timestamp.sec <= sd->sd_mtime.sec
 283#endif
 284                );
 285}
 286
 287static int is_racy_timestamp(const struct index_state *istate,
 288                             const struct cache_entry *ce)
 289{
 290        return (!S_ISGITLINK(ce->ce_mode) &&
 291                is_racy_stat(istate, &ce->ce_stat_data));
 292}
 293
 294int match_stat_data_racy(const struct index_state *istate,
 295                         const struct stat_data *sd, struct stat *st)
 296{
 297        if (is_racy_stat(istate, sd))
 298                return MTIME_CHANGED;
 299        return match_stat_data(sd, st);
 300}
 301
 302int ie_match_stat(const struct index_state *istate,
 303                  const struct cache_entry *ce, struct stat *st,
 304                  unsigned int options)
 305{
 306        unsigned int changed;
 307        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 308        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
 309        int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 310
 311        /*
 312         * If it's marked as always valid in the index, it's
 313         * valid whatever the checked-out copy says.
 314         *
 315         * skip-worktree has the same effect with higher precedence
 316         */
 317        if (!ignore_skip_worktree && ce_skip_worktree(ce))
 318                return 0;
 319        if (!ignore_valid && (ce->ce_flags & CE_VALID))
 320                return 0;
 321
 322        /*
 323         * Intent-to-add entries have not been added, so the index entry
 324         * by definition never matches what is in the work tree until it
 325         * actually gets added.
 326         */
 327        if (ce_intent_to_add(ce))
 328                return DATA_CHANGED | TYPE_CHANGED | MODE_CHANGED;
 329
 330        changed = ce_match_stat_basic(ce, st);
 331
 332        /*
 333         * Within 1 second of this sequence:
 334         *      echo xyzzy >file && git-update-index --add file
 335         * running this command:
 336         *      echo frotz >file
 337         * would give a falsely clean cache entry.  The mtime and
 338         * length match the cache, and other stat fields do not change.
 339         *
 340         * We could detect this at update-index time (the cache entry
 341         * being registered/updated records the same time as "now")
 342         * and delay the return from git-update-index, but that would
 343         * effectively mean we can make at most one commit per second,
 344         * which is not acceptable.  Instead, we check cache entries
 345         * whose mtime are the same as the index file timestamp more
 346         * carefully than others.
 347         */
 348        if (!changed && is_racy_timestamp(istate, ce)) {
 349                if (assume_racy_is_modified)
 350                        changed |= DATA_CHANGED;
 351                else
 352                        changed |= ce_modified_check_fs(ce, st);
 353        }
 354
 355        return changed;
 356}
 357
 358int ie_modified(const struct index_state *istate,
 359                const struct cache_entry *ce,
 360                struct stat *st, unsigned int options)
 361{
 362        int changed, changed_fs;
 363
 364        changed = ie_match_stat(istate, ce, st, options);
 365        if (!changed)
 366                return 0;
 367        /*
 368         * If the mode or type has changed, there's no point in trying
 369         * to refresh the entry - it's not going to match
 370         */
 371        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 372                return changed;
 373
 374        /*
 375         * Immediately after read-tree or update-index --cacheinfo,
 376         * the length field is zero, as we have never even read the
 377         * lstat(2) information once, and we cannot trust DATA_CHANGED
 378         * returned by ie_match_stat() which in turn was returned by
 379         * ce_match_stat_basic() to signal that the filesize of the
 380         * blob changed.  We have to actually go to the filesystem to
 381         * see if the contents match, and if so, should answer "unchanged".
 382         *
 383         * The logic does not apply to gitlinks, as ce_match_stat_basic()
 384         * already has checked the actual HEAD from the filesystem in the
 385         * subproject.  If ie_match_stat() already said it is different,
 386         * then we know it is.
 387         */
 388        if ((changed & DATA_CHANGED) &&
 389            (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0))
 390                return changed;
 391
 392        changed_fs = ce_modified_check_fs(ce, st);
 393        if (changed_fs)
 394                return changed | changed_fs;
 395        return 0;
 396}
 397
 398int base_name_compare(const char *name1, int len1, int mode1,
 399                      const char *name2, int len2, int mode2)
 400{
 401        unsigned char c1, c2;
 402        int len = len1 < len2 ? len1 : len2;
 403        int cmp;
 404
 405        cmp = memcmp(name1, name2, len);
 406        if (cmp)
 407                return cmp;
 408        c1 = name1[len];
 409        c2 = name2[len];
 410        if (!c1 && S_ISDIR(mode1))
 411                c1 = '/';
 412        if (!c2 && S_ISDIR(mode2))
 413                c2 = '/';
 414        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 415}
 416
 417/*
 418 * df_name_compare() is identical to base_name_compare(), except it
 419 * compares conflicting directory/file entries as equal. Note that
 420 * while a directory name compares as equal to a regular file, they
 421 * then individually compare _differently_ to a filename that has
 422 * a dot after the basename (because '\0' < '.' < '/').
 423 *
 424 * This is used by routines that want to traverse the git namespace
 425 * but then handle conflicting entries together when possible.
 426 */
 427int df_name_compare(const char *name1, int len1, int mode1,
 428                    const char *name2, int len2, int mode2)
 429{
 430        int len = len1 < len2 ? len1 : len2, cmp;
 431        unsigned char c1, c2;
 432
 433        cmp = memcmp(name1, name2, len);
 434        if (cmp)
 435                return cmp;
 436        /* Directories and files compare equal (same length, same name) */
 437        if (len1 == len2)
 438                return 0;
 439        c1 = name1[len];
 440        if (!c1 && S_ISDIR(mode1))
 441                c1 = '/';
 442        c2 = name2[len];
 443        if (!c2 && S_ISDIR(mode2))
 444                c2 = '/';
 445        if (c1 == '/' && !c2)
 446                return 0;
 447        if (c2 == '/' && !c1)
 448                return 0;
 449        return c1 - c2;
 450}
 451
 452int name_compare(const char *name1, size_t len1, const char *name2, size_t len2)
 453{
 454        size_t min_len = (len1 < len2) ? len1 : len2;
 455        int cmp = memcmp(name1, name2, min_len);
 456        if (cmp)
 457                return cmp;
 458        if (len1 < len2)
 459                return -1;
 460        if (len1 > len2)
 461                return 1;
 462        return 0;
 463}
 464
 465int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
 466{
 467        int cmp;
 468
 469        cmp = name_compare(name1, len1, name2, len2);
 470        if (cmp)
 471                return cmp;
 472
 473        if (stage1 < stage2)
 474                return -1;
 475        if (stage1 > stage2)
 476                return 1;
 477        return 0;
 478}
 479
 480static int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage)
 481{
 482        int first, last;
 483
 484        first = 0;
 485        last = istate->cache_nr;
 486        while (last > first) {
 487                int next = (last + first) >> 1;
 488                struct cache_entry *ce = istate->cache[next];
 489                int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce));
 490                if (!cmp)
 491                        return next;
 492                if (cmp < 0) {
 493                        last = next;
 494                        continue;
 495                }
 496                first = next+1;
 497        }
 498        return -first-1;
 499}
 500
 501int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 502{
 503        return index_name_stage_pos(istate, name, namelen, 0);
 504}
 505
 506int remove_index_entry_at(struct index_state *istate, int pos)
 507{
 508        struct cache_entry *ce = istate->cache[pos];
 509
 510        record_resolve_undo(istate, ce);
 511        remove_name_hash(istate, ce);
 512        save_or_free_index_entry(istate, ce);
 513        istate->cache_changed |= CE_ENTRY_REMOVED;
 514        istate->cache_nr--;
 515        if (pos >= istate->cache_nr)
 516                return 0;
 517        memmove(istate->cache + pos,
 518                istate->cache + pos + 1,
 519                (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 520        return 1;
 521}
 522
 523/*
 524 * Remove all cache entries marked for removal, that is where
 525 * CE_REMOVE is set in ce_flags.  This is much more effective than
 526 * calling remove_index_entry_at() for each entry to be removed.
 527 */
 528void remove_marked_cache_entries(struct index_state *istate)
 529{
 530        struct cache_entry **ce_array = istate->cache;
 531        unsigned int i, j;
 532
 533        for (i = j = 0; i < istate->cache_nr; i++) {
 534                if (ce_array[i]->ce_flags & CE_REMOVE) {
 535                        remove_name_hash(istate, ce_array[i]);
 536                        save_or_free_index_entry(istate, ce_array[i]);
 537                }
 538                else
 539                        ce_array[j++] = ce_array[i];
 540        }
 541        if (j == istate->cache_nr)
 542                return;
 543        istate->cache_changed |= CE_ENTRY_REMOVED;
 544        istate->cache_nr = j;
 545}
 546
 547int remove_file_from_index(struct index_state *istate, const char *path)
 548{
 549        int pos = index_name_pos(istate, path, strlen(path));
 550        if (pos < 0)
 551                pos = -pos-1;
 552        cache_tree_invalidate_path(istate, path);
 553        untracked_cache_remove_from_index(istate, path);
 554        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 555                remove_index_entry_at(istate, pos);
 556        return 0;
 557}
 558
 559static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 560{
 561        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 562}
 563
 564static int index_name_pos_also_unmerged(struct index_state *istate,
 565        const char *path, int namelen)
 566{
 567        int pos = index_name_pos(istate, path, namelen);
 568        struct cache_entry *ce;
 569
 570        if (pos >= 0)
 571                return pos;
 572
 573        /* maybe unmerged? */
 574        pos = -1 - pos;
 575        if (pos >= istate->cache_nr ||
 576                        compare_name((ce = istate->cache[pos]), path, namelen))
 577                return -1;
 578
 579        /* order of preference: stage 2, 1, 3 */
 580        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 581                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 582                        !compare_name(ce, path, namelen))
 583                pos++;
 584        return pos;
 585}
 586
 587static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 588{
 589        int len = ce_namelen(ce);
 590        return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 591}
 592
 593/*
 594 * If we add a filename that aliases in the cache, we will use the
 595 * name that we already have - but we don't want to update the same
 596 * alias twice, because that implies that there were actually two
 597 * different files with aliasing names!
 598 *
 599 * So we use the CE_ADDED flag to verify that the alias was an old
 600 * one before we accept it as
 601 */
 602static struct cache_entry *create_alias_ce(struct index_state *istate,
 603                                           struct cache_entry *ce,
 604                                           struct cache_entry *alias)
 605{
 606        int len;
 607        struct cache_entry *new;
 608
 609        if (alias->ce_flags & CE_ADDED)
 610                die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 611
 612        /* Ok, create the new entry using the name of the existing alias */
 613        len = ce_namelen(alias);
 614        new = xcalloc(1, cache_entry_size(len));
 615        memcpy(new->name, alias->name, len);
 616        copy_cache_entry(new, ce);
 617        save_or_free_index_entry(istate, ce);
 618        return new;
 619}
 620
 621void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 622{
 623        unsigned char sha1[20];
 624        if (write_sha1_file("", 0, blob_type, sha1))
 625                die("cannot create an empty blob in the object database");
 626        hashcpy(ce->oid.hash, sha1);
 627}
 628
 629int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 630{
 631        int size, namelen, was_same;
 632        mode_t st_mode = st->st_mode;
 633        struct cache_entry *ce, *alias;
 634        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE|CE_MATCH_RACY_IS_DIRTY;
 635        int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 636        int pretend = flags & ADD_CACHE_PRETEND;
 637        int intent_only = flags & ADD_CACHE_INTENT;
 638        int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 639                          (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 640
 641        if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 642                return error("%s: can only add regular files, symbolic links or git-directories", path);
 643
 644        namelen = strlen(path);
 645        if (S_ISDIR(st_mode)) {
 646                while (namelen && path[namelen-1] == '/')
 647                        namelen--;
 648        }
 649        size = cache_entry_size(namelen);
 650        ce = xcalloc(1, size);
 651        memcpy(ce->name, path, namelen);
 652        ce->ce_namelen = namelen;
 653        if (!intent_only)
 654                fill_stat_cache_info(ce, st);
 655        else
 656                ce->ce_flags |= CE_INTENT_TO_ADD;
 657
 658
 659        if (trust_executable_bit && has_symlinks) {
 660                ce->ce_mode = create_ce_mode(st_mode);
 661        } else {
 662                /* If there is an existing entry, pick the mode bits and type
 663                 * from it, otherwise assume unexecutable regular file.
 664                 */
 665                struct cache_entry *ent;
 666                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 667
 668                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 669                ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 670        }
 671
 672        /* When core.ignorecase=true, determine if a directory of the same name but differing
 673         * case already exists within the Git repository.  If it does, ensure the directory
 674         * case of the file being added to the repository matches (is folded into) the existing
 675         * entry's directory case.
 676         */
 677        if (ignore_case) {
 678                adjust_dirname_case(istate, ce->name);
 679        }
 680
 681        alias = index_file_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 682        if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 683                /* Nothing changed, really */
 684                if (!S_ISGITLINK(alias->ce_mode))
 685                        ce_mark_uptodate(alias);
 686                alias->ce_flags |= CE_ADDED;
 687
 688                free(ce);
 689                return 0;
 690        }
 691        if (!intent_only) {
 692                if (index_path(ce->oid.hash, path, st, HASH_WRITE_OBJECT)) {
 693                        free(ce);
 694                        return error("unable to index file %s", path);
 695                }
 696        } else
 697                set_object_name_for_intent_to_add_entry(ce);
 698
 699        if (ignore_case && alias && different_name(ce, alias))
 700                ce = create_alias_ce(istate, ce, alias);
 701        ce->ce_flags |= CE_ADDED;
 702
 703        /* It was suspected to be racily clean, but it turns out to be Ok */
 704        was_same = (alias &&
 705                    !ce_stage(alias) &&
 706                    !oidcmp(&alias->oid, &ce->oid) &&
 707                    ce->ce_mode == alias->ce_mode);
 708
 709        if (pretend)
 710                free(ce);
 711        else if (add_index_entry(istate, ce, add_option)) {
 712                free(ce);
 713                return error("unable to add %s to index", path);
 714        }
 715        if (verbose && !was_same)
 716                printf("add '%s'\n", path);
 717        return 0;
 718}
 719
 720int add_file_to_index(struct index_state *istate, const char *path, int flags)
 721{
 722        struct stat st;
 723        if (lstat(path, &st))
 724                die_errno("unable to stat '%s'", path);
 725        return add_to_index(istate, path, &st, flags);
 726}
 727
 728struct cache_entry *make_cache_entry(unsigned int mode,
 729                const unsigned char *sha1, const char *path, int stage,
 730                unsigned int refresh_options)
 731{
 732        int size, len;
 733        struct cache_entry *ce, *ret;
 734
 735        if (!verify_path(path)) {
 736                error("Invalid path '%s'", path);
 737                return NULL;
 738        }
 739
 740        len = strlen(path);
 741        size = cache_entry_size(len);
 742        ce = xcalloc(1, size);
 743
 744        hashcpy(ce->oid.hash, sha1);
 745        memcpy(ce->name, path, len);
 746        ce->ce_flags = create_ce_flags(stage);
 747        ce->ce_namelen = len;
 748        ce->ce_mode = create_ce_mode(mode);
 749
 750        ret = refresh_cache_entry(ce, refresh_options);
 751        if (ret != ce)
 752                free(ce);
 753        return ret;
 754}
 755
 756/*
 757 * Chmod an index entry with either +x or -x.
 758 *
 759 * Returns -1 if the chmod for the particular cache entry failed (if it's
 760 * not a regular file), -2 if an invalid flip argument is passed in, 0
 761 * otherwise.
 762 */
 763int chmod_index_entry(struct index_state *istate, struct cache_entry *ce,
 764                      char flip)
 765{
 766        if (!S_ISREG(ce->ce_mode))
 767                return -1;
 768        switch (flip) {
 769        case '+':
 770                ce->ce_mode |= 0111;
 771                break;
 772        case '-':
 773                ce->ce_mode &= ~0111;
 774                break;
 775        default:
 776                return -2;
 777        }
 778        cache_tree_invalidate_path(istate, ce->name);
 779        ce->ce_flags |= CE_UPDATE_IN_BASE;
 780        istate->cache_changed |= CE_ENTRY_CHANGED;
 781
 782        return 0;
 783}
 784
 785int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 786{
 787        int len = ce_namelen(a);
 788        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 789}
 790
 791/*
 792 * We fundamentally don't like some paths: we don't want
 793 * dot or dot-dot anywhere, and for obvious reasons don't
 794 * want to recurse into ".git" either.
 795 *
 796 * Also, we don't want double slashes or slashes at the
 797 * end that can make pathnames ambiguous.
 798 */
 799static int verify_dotfile(const char *rest)
 800{
 801        /*
 802         * The first character was '.', but that
 803         * has already been discarded, we now test
 804         * the rest.
 805         */
 806
 807        /* "." is not allowed */
 808        if (*rest == '\0' || is_dir_sep(*rest))
 809                return 0;
 810
 811        switch (*rest) {
 812        /*
 813         * ".git" followed by  NUL or slash is bad. This
 814         * shares the path end test with the ".." case.
 815         */
 816        case 'g':
 817        case 'G':
 818                if (rest[1] != 'i' && rest[1] != 'I')
 819                        break;
 820                if (rest[2] != 't' && rest[2] != 'T')
 821                        break;
 822                rest += 2;
 823        /* fallthrough */
 824        case '.':
 825                if (rest[1] == '\0' || is_dir_sep(rest[1]))
 826                        return 0;
 827        }
 828        return 1;
 829}
 830
 831int verify_path(const char *path)
 832{
 833        char c;
 834
 835        if (has_dos_drive_prefix(path))
 836                return 0;
 837
 838        goto inside;
 839        for (;;) {
 840                if (!c)
 841                        return 1;
 842                if (is_dir_sep(c)) {
 843inside:
 844                        if (protect_hfs && is_hfs_dotgit(path))
 845                                return 0;
 846                        if (protect_ntfs && is_ntfs_dotgit(path))
 847                                return 0;
 848                        c = *path++;
 849                        if ((c == '.' && !verify_dotfile(path)) ||
 850                            is_dir_sep(c) || c == '\0')
 851                                return 0;
 852                }
 853                c = *path++;
 854        }
 855}
 856
 857/*
 858 * Do we have another file that has the beginning components being a
 859 * proper superset of the name we're trying to add?
 860 */
 861static int has_file_name(struct index_state *istate,
 862                         const struct cache_entry *ce, int pos, int ok_to_replace)
 863{
 864        int retval = 0;
 865        int len = ce_namelen(ce);
 866        int stage = ce_stage(ce);
 867        const char *name = ce->name;
 868
 869        while (pos < istate->cache_nr) {
 870                struct cache_entry *p = istate->cache[pos++];
 871
 872                if (len >= ce_namelen(p))
 873                        break;
 874                if (memcmp(name, p->name, len))
 875                        break;
 876                if (ce_stage(p) != stage)
 877                        continue;
 878                if (p->name[len] != '/')
 879                        continue;
 880                if (p->ce_flags & CE_REMOVE)
 881                        continue;
 882                retval = -1;
 883                if (!ok_to_replace)
 884                        break;
 885                remove_index_entry_at(istate, --pos);
 886        }
 887        return retval;
 888}
 889
 890
 891/*
 892 * Like strcmp(), but also return the offset of the first change.
 893 * If strings are equal, return the length.
 894 */
 895int strcmp_offset(const char *s1, const char *s2, size_t *first_change)
 896{
 897        size_t k;
 898
 899        if (!first_change)
 900                return strcmp(s1, s2);
 901
 902        for (k = 0; s1[k] == s2[k]; k++)
 903                if (s1[k] == '\0')
 904                        break;
 905
 906        *first_change = k;
 907        return (unsigned char)s1[k] - (unsigned char)s2[k];
 908}
 909
 910/*
 911 * Do we have another file with a pathname that is a proper
 912 * subset of the name we're trying to add?
 913 *
 914 * That is, is there another file in the index with a path
 915 * that matches a sub-directory in the given entry?
 916 */
 917static int has_dir_name(struct index_state *istate,
 918                        const struct cache_entry *ce, int pos, int ok_to_replace)
 919{
 920        int retval = 0;
 921        int stage = ce_stage(ce);
 922        const char *name = ce->name;
 923        const char *slash = name + ce_namelen(ce);
 924        size_t len_eq_last;
 925        int cmp_last = 0;
 926
 927        /*
 928         * We are frequently called during an iteration on a sorted
 929         * list of pathnames and while building a new index.  Therefore,
 930         * there is a high probability that this entry will eventually
 931         * be appended to the index, rather than inserted in the middle.
 932         * If we can confirm that, we can avoid binary searches on the
 933         * components of the pathname.
 934         *
 935         * Compare the entry's full path with the last path in the index.
 936         */
 937        if (istate->cache_nr > 0) {
 938                cmp_last = strcmp_offset(name,
 939                        istate->cache[istate->cache_nr - 1]->name,
 940                        &len_eq_last);
 941                if (cmp_last > 0) {
 942                        if (len_eq_last == 0) {
 943                                /*
 944                                 * The entry sorts AFTER the last one in the
 945                                 * index and their paths have no common prefix,
 946                                 * so there cannot be a F/D conflict.
 947                                 */
 948                                return retval;
 949                        } else {
 950                                /*
 951                                 * The entry sorts AFTER the last one in the
 952                                 * index, but has a common prefix.  Fall through
 953                                 * to the loop below to disect the entry's path
 954                                 * and see where the difference is.
 955                                 */
 956                        }
 957                } else if (cmp_last == 0) {
 958                        /*
 959                         * The entry exactly matches the last one in the
 960                         * index, but because of multiple stage and CE_REMOVE
 961                         * items, we fall through and let the regular search
 962                         * code handle it.
 963                         */
 964                }
 965        }
 966
 967        for (;;) {
 968                size_t len;
 969
 970                for (;;) {
 971                        if (*--slash == '/')
 972                                break;
 973                        if (slash <= ce->name)
 974                                return retval;
 975                }
 976                len = slash - name;
 977
 978                if (cmp_last > 0) {
 979                        /*
 980                         * (len + 1) is a directory boundary (including
 981                         * the trailing slash).  And since the loop is
 982                         * decrementing "slash", the first iteration is
 983                         * the longest directory prefix; subsequent
 984                         * iterations consider parent directories.
 985                         */
 986
 987                        if (len + 1 <= len_eq_last) {
 988                                /*
 989                                 * The directory prefix (including the trailing
 990                                 * slash) also appears as a prefix in the last
 991                                 * entry, so the remainder cannot collide (because
 992                                 * strcmp said the whole path was greater).
 993                                 *
 994                                 * EQ: last: xxx/A
 995                                 *     this: xxx/B
 996                                 *
 997                                 * LT: last: xxx/file_A
 998                                 *     this: xxx/file_B
 999                                 */
1000                                return retval;
1001                        }
1002
1003                        if (len > len_eq_last) {
1004                                /*
1005                                 * This part of the directory prefix (excluding
1006                                 * the trailing slash) is longer than the known
1007                                 * equal portions, so this sub-directory cannot
1008                                 * collide with a file.
1009                                 *
1010                                 * GT: last: xxxA
1011                                 *     this: xxxB/file
1012                                 */
1013                                return retval;
1014                        }
1015
1016                        if (istate->cache_nr > 0 &&
1017                                ce_namelen(istate->cache[istate->cache_nr - 1]) > len) {
1018                                /*
1019                                 * The directory prefix lines up with part of
1020                                 * a longer file or directory name, but sorts
1021                                 * after it, so this sub-directory cannot
1022                                 * collide with a file.
1023                                 *
1024                                 * last: xxx/yy-file (because '-' sorts before '/')
1025                                 * this: xxx/yy/abc
1026                                 */
1027                                return retval;
1028                        }
1029
1030                        /*
1031                         * This is a possible collision. Fall through and
1032                         * let the regular search code handle it.
1033                         *
1034                         * last: xxx
1035                         * this: xxx/file
1036                         */
1037                }
1038
1039                pos = index_name_stage_pos(istate, name, len, stage);
1040                if (pos >= 0) {
1041                        /*
1042                         * Found one, but not so fast.  This could
1043                         * be a marker that says "I was here, but
1044                         * I am being removed".  Such an entry is
1045                         * not a part of the resulting tree, and
1046                         * it is Ok to have a directory at the same
1047                         * path.
1048                         */
1049                        if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
1050                                retval = -1;
1051                                if (!ok_to_replace)
1052                                        break;
1053                                remove_index_entry_at(istate, pos);
1054                                continue;
1055                        }
1056                }
1057                else
1058                        pos = -pos-1;
1059
1060                /*
1061                 * Trivial optimization: if we find an entry that
1062                 * already matches the sub-directory, then we know
1063                 * we're ok, and we can exit.
1064                 */
1065                while (pos < istate->cache_nr) {
1066                        struct cache_entry *p = istate->cache[pos];
1067                        if ((ce_namelen(p) <= len) ||
1068                            (p->name[len] != '/') ||
1069                            memcmp(p->name, name, len))
1070                                break; /* not our subdirectory */
1071                        if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
1072                                /*
1073                                 * p is at the same stage as our entry, and
1074                                 * is a subdirectory of what we are looking
1075                                 * at, so we cannot have conflicts at our
1076                                 * level or anything shorter.
1077                                 */
1078                                return retval;
1079                        pos++;
1080                }
1081        }
1082        return retval;
1083}
1084
1085/* We may be in a situation where we already have path/file and path
1086 * is being added, or we already have path and path/file is being
1087 * added.  Either one would result in a nonsense tree that has path
1088 * twice when git-write-tree tries to write it out.  Prevent it.
1089 *
1090 * If ok-to-replace is specified, we remove the conflicting entries
1091 * from the cache so the caller should recompute the insert position.
1092 * When this happens, we return non-zero.
1093 */
1094static int check_file_directory_conflict(struct index_state *istate,
1095                                         const struct cache_entry *ce,
1096                                         int pos, int ok_to_replace)
1097{
1098        int retval;
1099
1100        /*
1101         * When ce is an "I am going away" entry, we allow it to be added
1102         */
1103        if (ce->ce_flags & CE_REMOVE)
1104                return 0;
1105
1106        /*
1107         * We check if the path is a sub-path of a subsequent pathname
1108         * first, since removing those will not change the position
1109         * in the array.
1110         */
1111        retval = has_file_name(istate, ce, pos, ok_to_replace);
1112
1113        /*
1114         * Then check if the path might have a clashing sub-directory
1115         * before it.
1116         */
1117        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
1118}
1119
1120static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
1121{
1122        int pos;
1123        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
1124        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
1125        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
1126        int new_only = option & ADD_CACHE_NEW_ONLY;
1127
1128        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1129                cache_tree_invalidate_path(istate, ce->name);
1130
1131        /*
1132         * If this entry's path sorts after the last entry in the index,
1133         * we can avoid searching for it.
1134         */
1135        if (istate->cache_nr > 0 &&
1136                strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0)
1137                pos = -istate->cache_nr - 1;
1138        else
1139                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1140
1141        /* existing match? Just replace it. */
1142        if (pos >= 0) {
1143                if (!new_only)
1144                        replace_index_entry(istate, pos, ce);
1145                return 0;
1146        }
1147        pos = -pos-1;
1148
1149        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
1150                untracked_cache_add_to_index(istate, ce->name);
1151
1152        /*
1153         * Inserting a merged entry ("stage 0") into the index
1154         * will always replace all non-merged entries..
1155         */
1156        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
1157                while (ce_same_name(istate->cache[pos], ce)) {
1158                        ok_to_add = 1;
1159                        if (!remove_index_entry_at(istate, pos))
1160                                break;
1161                }
1162        }
1163
1164        if (!ok_to_add)
1165                return -1;
1166        if (!verify_path(ce->name))
1167                return error("Invalid path '%s'", ce->name);
1168
1169        if (!skip_df_check &&
1170            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
1171                if (!ok_to_replace)
1172                        return error("'%s' appears as both a file and as a directory",
1173                                     ce->name);
1174                pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
1175                pos = -pos-1;
1176        }
1177        return pos + 1;
1178}
1179
1180int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
1181{
1182        int pos;
1183
1184        if (option & ADD_CACHE_JUST_APPEND)
1185                pos = istate->cache_nr;
1186        else {
1187                int ret;
1188                ret = add_index_entry_with_check(istate, ce, option);
1189                if (ret <= 0)
1190                        return ret;
1191                pos = ret - 1;
1192        }
1193
1194        /* Make sure the array is big enough .. */
1195        ALLOC_GROW(istate->cache, istate->cache_nr + 1, istate->cache_alloc);
1196
1197        /* Add it in.. */
1198        istate->cache_nr++;
1199        if (istate->cache_nr > pos + 1)
1200                memmove(istate->cache + pos + 1,
1201                        istate->cache + pos,
1202                        (istate->cache_nr - pos - 1) * sizeof(ce));
1203        set_index_entry(istate, pos, ce);
1204        istate->cache_changed |= CE_ENTRY_ADDED;
1205        return 0;
1206}
1207
1208/*
1209 * "refresh" does not calculate a new sha1 file or bring the
1210 * cache up-to-date for mode/content changes. But what it
1211 * _does_ do is to "re-match" the stat information of a file
1212 * with the cache, so that you can refresh the cache for a
1213 * file that hasn't been changed but where the stat entry is
1214 * out of date.
1215 *
1216 * For example, you'd want to do this after doing a "git-read-tree",
1217 * to link up the stat cache details with the proper files.
1218 */
1219static struct cache_entry *refresh_cache_ent(struct index_state *istate,
1220                                             struct cache_entry *ce,
1221                                             unsigned int options, int *err,
1222                                             int *changed_ret)
1223{
1224        struct stat st;
1225        struct cache_entry *updated;
1226        int changed, size;
1227        int refresh = options & CE_MATCH_REFRESH;
1228        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
1229        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
1230        int ignore_missing = options & CE_MATCH_IGNORE_MISSING;
1231
1232        if (!refresh || ce_uptodate(ce))
1233                return ce;
1234
1235        /*
1236         * CE_VALID or CE_SKIP_WORKTREE means the user promised us
1237         * that the change to the work tree does not matter and told
1238         * us not to worry.
1239         */
1240        if (!ignore_skip_worktree && ce_skip_worktree(ce)) {
1241                ce_mark_uptodate(ce);
1242                return ce;
1243        }
1244        if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
1245                ce_mark_uptodate(ce);
1246                return ce;
1247        }
1248
1249        if (has_symlink_leading_path(ce->name, ce_namelen(ce))) {
1250                if (ignore_missing)
1251                        return ce;
1252                if (err)
1253                        *err = ENOENT;
1254                return NULL;
1255        }
1256
1257        if (lstat(ce->name, &st) < 0) {
1258                if (ignore_missing && errno == ENOENT)
1259                        return ce;
1260                if (err)
1261                        *err = errno;
1262                return NULL;
1263        }
1264
1265        changed = ie_match_stat(istate, ce, &st, options);
1266        if (changed_ret)
1267                *changed_ret = changed;
1268        if (!changed) {
1269                /*
1270                 * The path is unchanged.  If we were told to ignore
1271                 * valid bit, then we did the actual stat check and
1272                 * found that the entry is unmodified.  If the entry
1273                 * is not marked VALID, this is the place to mark it
1274                 * valid again, under "assume unchanged" mode.
1275                 */
1276                if (ignore_valid && assume_unchanged &&
1277                    !(ce->ce_flags & CE_VALID))
1278                        ; /* mark this one VALID again */
1279                else {
1280                        /*
1281                         * We do not mark the index itself "modified"
1282                         * because CE_UPTODATE flag is in-core only;
1283                         * we are not going to write this change out.
1284                         */
1285                        if (!S_ISGITLINK(ce->ce_mode))
1286                                ce_mark_uptodate(ce);
1287                        return ce;
1288                }
1289        }
1290
1291        if (ie_modified(istate, ce, &st, options)) {
1292                if (err)
1293                        *err = EINVAL;
1294                return NULL;
1295        }
1296
1297        size = ce_size(ce);
1298        updated = xmalloc(size);
1299        memcpy(updated, ce, size);
1300        fill_stat_cache_info(updated, &st);
1301        /*
1302         * If ignore_valid is not set, we should leave CE_VALID bit
1303         * alone.  Otherwise, paths marked with --no-assume-unchanged
1304         * (i.e. things to be edited) will reacquire CE_VALID bit
1305         * automatically, which is not really what we want.
1306         */
1307        if (!ignore_valid && assume_unchanged &&
1308            !(ce->ce_flags & CE_VALID))
1309                updated->ce_flags &= ~CE_VALID;
1310
1311        /* istate->cache_changed is updated in the caller */
1312        return updated;
1313}
1314
1315static void show_file(const char * fmt, const char * name, int in_porcelain,
1316                      int * first, const char *header_msg)
1317{
1318        if (in_porcelain && *first && header_msg) {
1319                printf("%s\n", header_msg);
1320                *first = 0;
1321        }
1322        printf(fmt, name);
1323}
1324
1325int refresh_index(struct index_state *istate, unsigned int flags,
1326                  const struct pathspec *pathspec,
1327                  char *seen, const char *header_msg)
1328{
1329        int i;
1330        int has_errors = 0;
1331        int really = (flags & REFRESH_REALLY) != 0;
1332        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
1333        int quiet = (flags & REFRESH_QUIET) != 0;
1334        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
1335        int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
1336        int first = 1;
1337        int in_porcelain = (flags & REFRESH_IN_PORCELAIN);
1338        unsigned int options = (CE_MATCH_REFRESH |
1339                                (really ? CE_MATCH_IGNORE_VALID : 0) |
1340                                (not_new ? CE_MATCH_IGNORE_MISSING : 0));
1341        const char *modified_fmt;
1342        const char *deleted_fmt;
1343        const char *typechange_fmt;
1344        const char *added_fmt;
1345        const char *unmerged_fmt;
1346
1347        modified_fmt = (in_porcelain ? "M\t%s\n" : "%s: needs update\n");
1348        deleted_fmt = (in_porcelain ? "D\t%s\n" : "%s: needs update\n");
1349        typechange_fmt = (in_porcelain ? "T\t%s\n" : "%s needs update\n");
1350        added_fmt = (in_porcelain ? "A\t%s\n" : "%s needs update\n");
1351        unmerged_fmt = (in_porcelain ? "U\t%s\n" : "%s: needs merge\n");
1352        for (i = 0; i < istate->cache_nr; i++) {
1353                struct cache_entry *ce, *new;
1354                int cache_errno = 0;
1355                int changed = 0;
1356                int filtered = 0;
1357
1358                ce = istate->cache[i];
1359                if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
1360                        continue;
1361
1362                if (pathspec && !ce_path_match(ce, pathspec, seen))
1363                        filtered = 1;
1364
1365                if (ce_stage(ce)) {
1366                        while ((i < istate->cache_nr) &&
1367                               ! strcmp(istate->cache[i]->name, ce->name))
1368                                i++;
1369                        i--;
1370                        if (allow_unmerged)
1371                                continue;
1372                        if (!filtered)
1373                                show_file(unmerged_fmt, ce->name, in_porcelain,
1374                                          &first, header_msg);
1375                        has_errors = 1;
1376                        continue;
1377                }
1378
1379                if (filtered)
1380                        continue;
1381
1382                new = refresh_cache_ent(istate, ce, options, &cache_errno, &changed);
1383                if (new == ce)
1384                        continue;
1385                if (!new) {
1386                        const char *fmt;
1387
1388                        if (really && cache_errno == EINVAL) {
1389                                /* If we are doing --really-refresh that
1390                                 * means the index is not valid anymore.
1391                                 */
1392                                ce->ce_flags &= ~CE_VALID;
1393                                ce->ce_flags |= CE_UPDATE_IN_BASE;
1394                                istate->cache_changed |= CE_ENTRY_CHANGED;
1395                        }
1396                        if (quiet)
1397                                continue;
1398
1399                        if (cache_errno == ENOENT)
1400                                fmt = deleted_fmt;
1401                        else if (ce_intent_to_add(ce))
1402                                fmt = added_fmt; /* must be before other checks */
1403                        else if (changed & TYPE_CHANGED)
1404                                fmt = typechange_fmt;
1405                        else
1406                                fmt = modified_fmt;
1407                        show_file(fmt,
1408                                  ce->name, in_porcelain, &first, header_msg);
1409                        has_errors = 1;
1410                        continue;
1411                }
1412
1413                replace_index_entry(istate, i, new);
1414        }
1415        return has_errors;
1416}
1417
1418struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
1419                                               unsigned int options)
1420{
1421        return refresh_cache_ent(&the_index, ce, options, NULL, NULL);
1422}
1423
1424
1425/*****************************************************************
1426 * Index File I/O
1427 *****************************************************************/
1428
1429#define INDEX_FORMAT_DEFAULT 3
1430
1431static unsigned int get_index_format_default(void)
1432{
1433        char *envversion = getenv("GIT_INDEX_VERSION");
1434        char *endp;
1435        int value;
1436        unsigned int version = INDEX_FORMAT_DEFAULT;
1437
1438        if (!envversion) {
1439                if (!git_config_get_int("index.version", &value))
1440                        version = value;
1441                if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1442                        warning(_("index.version set, but the value is invalid.\n"
1443                                  "Using version %i"), INDEX_FORMAT_DEFAULT);
1444                        return INDEX_FORMAT_DEFAULT;
1445                }
1446                return version;
1447        }
1448
1449        version = strtoul(envversion, &endp, 10);
1450        if (*endp ||
1451            version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) {
1452                warning(_("GIT_INDEX_VERSION set, but the value is invalid.\n"
1453                          "Using version %i"), INDEX_FORMAT_DEFAULT);
1454                version = INDEX_FORMAT_DEFAULT;
1455        }
1456        return version;
1457}
1458
1459/*
1460 * dev/ino/uid/gid/size are also just tracked to the low 32 bits
1461 * Again - this is just a (very strong in practice) heuristic that
1462 * the inode hasn't changed.
1463 *
1464 * We save the fields in big-endian order to allow using the
1465 * index file over NFS transparently.
1466 */
1467struct ondisk_cache_entry {
1468        struct cache_time ctime;
1469        struct cache_time mtime;
1470        uint32_t dev;
1471        uint32_t ino;
1472        uint32_t mode;
1473        uint32_t uid;
1474        uint32_t gid;
1475        uint32_t size;
1476        unsigned char sha1[20];
1477        uint16_t flags;
1478        char name[FLEX_ARRAY]; /* more */
1479};
1480
1481/*
1482 * This struct is used when CE_EXTENDED bit is 1
1483 * The struct must match ondisk_cache_entry exactly from
1484 * ctime till flags
1485 */
1486struct ondisk_cache_entry_extended {
1487        struct cache_time ctime;
1488        struct cache_time mtime;
1489        uint32_t dev;
1490        uint32_t ino;
1491        uint32_t mode;
1492        uint32_t uid;
1493        uint32_t gid;
1494        uint32_t size;
1495        unsigned char sha1[20];
1496        uint16_t flags;
1497        uint16_t flags2;
1498        char name[FLEX_ARRAY]; /* more */
1499};
1500
1501/* These are only used for v3 or lower */
1502#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
1503#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
1504#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
1505#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
1506                            ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
1507                            ondisk_cache_entry_size(ce_namelen(ce)))
1508
1509/* Allow fsck to force verification of the index checksum. */
1510int verify_index_checksum;
1511
1512static int verify_hdr(struct cache_header *hdr, unsigned long size)
1513{
1514        git_SHA_CTX c;
1515        unsigned char sha1[20];
1516        int hdr_version;
1517
1518        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1519                return error("bad signature");
1520        hdr_version = ntohl(hdr->hdr_version);
1521        if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version)
1522                return error("bad index version %d", hdr_version);
1523
1524        if (!verify_index_checksum)
1525                return 0;
1526
1527        git_SHA1_Init(&c);
1528        git_SHA1_Update(&c, hdr, size - 20);
1529        git_SHA1_Final(sha1, &c);
1530        if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1531                return error("bad index file sha1 signature");
1532        return 0;
1533}
1534
1535static int read_index_extension(struct index_state *istate,
1536                                const char *ext, void *data, unsigned long sz)
1537{
1538        switch (CACHE_EXT(ext)) {
1539        case CACHE_EXT_TREE:
1540                istate->cache_tree = cache_tree_read(data, sz);
1541                break;
1542        case CACHE_EXT_RESOLVE_UNDO:
1543                istate->resolve_undo = resolve_undo_read(data, sz);
1544                break;
1545        case CACHE_EXT_LINK:
1546                if (read_link_extension(istate, data, sz))
1547                        return -1;
1548                break;
1549        case CACHE_EXT_UNTRACKED:
1550                istate->untracked = read_untracked_extension(data, sz);
1551                break;
1552        default:
1553                if (*ext < 'A' || 'Z' < *ext)
1554                        return error("index uses %.4s extension, which we do not understand",
1555                                     ext);
1556                fprintf(stderr, "ignoring %.4s extension\n", ext);
1557                break;
1558        }
1559        return 0;
1560}
1561
1562int hold_locked_index(struct lock_file *lk, int lock_flags)
1563{
1564        return hold_lock_file_for_update(lk, get_index_file(), lock_flags);
1565}
1566
1567int read_index(struct index_state *istate)
1568{
1569        return read_index_from(istate, get_index_file());
1570}
1571
1572static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
1573                                                   unsigned int flags,
1574                                                   const char *name,
1575                                                   size_t len)
1576{
1577        struct cache_entry *ce = xmalloc(cache_entry_size(len));
1578
1579        ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
1580        ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
1581        ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec);
1582        ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec);
1583        ce->ce_stat_data.sd_dev   = get_be32(&ondisk->dev);
1584        ce->ce_stat_data.sd_ino   = get_be32(&ondisk->ino);
1585        ce->ce_mode  = get_be32(&ondisk->mode);
1586        ce->ce_stat_data.sd_uid   = get_be32(&ondisk->uid);
1587        ce->ce_stat_data.sd_gid   = get_be32(&ondisk->gid);
1588        ce->ce_stat_data.sd_size  = get_be32(&ondisk->size);
1589        ce->ce_flags = flags & ~CE_NAMEMASK;
1590        ce->ce_namelen = len;
1591        ce->index = 0;
1592        hashcpy(ce->oid.hash, ondisk->sha1);
1593        memcpy(ce->name, name, len);
1594        ce->name[len] = '\0';
1595        return ce;
1596}
1597
1598/*
1599 * Adjacent cache entries tend to share the leading paths, so it makes
1600 * sense to only store the differences in later entries.  In the v4
1601 * on-disk format of the index, each on-disk cache entry stores the
1602 * number of bytes to be stripped from the end of the previous name,
1603 * and the bytes to append to the result, to come up with its name.
1604 */
1605static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
1606{
1607        const unsigned char *ep, *cp = (const unsigned char *)cp_;
1608        size_t len = decode_varint(&cp);
1609
1610        if (name->len < len)
1611                die("malformed name field in the index");
1612        strbuf_remove(name, name->len - len, len);
1613        for (ep = cp; *ep; ep++)
1614                ; /* find the end */
1615        strbuf_add(name, cp, ep - cp);
1616        return (const char *)ep + 1 - cp_;
1617}
1618
1619static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
1620                                            unsigned long *ent_size,
1621                                            struct strbuf *previous_name)
1622{
1623        struct cache_entry *ce;
1624        size_t len;
1625        const char *name;
1626        unsigned int flags;
1627
1628        /* On-disk flags are just 16 bits */
1629        flags = get_be16(&ondisk->flags);
1630        len = flags & CE_NAMEMASK;
1631
1632        if (flags & CE_EXTENDED) {
1633                struct ondisk_cache_entry_extended *ondisk2;
1634                int extended_flags;
1635                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1636                extended_flags = get_be16(&ondisk2->flags2) << 16;
1637                /* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
1638                if (extended_flags & ~CE_EXTENDED_FLAGS)
1639                        die("Unknown index entry format %08x", extended_flags);
1640                flags |= extended_flags;
1641                name = ondisk2->name;
1642        }
1643        else
1644                name = ondisk->name;
1645
1646        if (!previous_name) {
1647                /* v3 and earlier */
1648                if (len == CE_NAMEMASK)
1649                        len = strlen(name);
1650                ce = cache_entry_from_ondisk(ondisk, flags, name, len);
1651
1652                *ent_size = ondisk_ce_size(ce);
1653        } else {
1654                unsigned long consumed;
1655                consumed = expand_name_field(previous_name, name);
1656                ce = cache_entry_from_ondisk(ondisk, flags,
1657                                             previous_name->buf,
1658                                             previous_name->len);
1659
1660                *ent_size = (name - ((char *)ondisk)) + consumed;
1661        }
1662        return ce;
1663}
1664
1665static void check_ce_order(struct index_state *istate)
1666{
1667        unsigned int i;
1668
1669        for (i = 1; i < istate->cache_nr; i++) {
1670                struct cache_entry *ce = istate->cache[i - 1];
1671                struct cache_entry *next_ce = istate->cache[i];
1672                int name_compare = strcmp(ce->name, next_ce->name);
1673
1674                if (0 < name_compare)
1675                        die("unordered stage entries in index");
1676                if (!name_compare) {
1677                        if (!ce_stage(ce))
1678                                die("multiple stage entries for merged file '%s'",
1679                                    ce->name);
1680                        if (ce_stage(ce) > ce_stage(next_ce))
1681                                die("unordered stage entries for '%s'",
1682                                    ce->name);
1683                }
1684        }
1685}
1686
1687static void tweak_untracked_cache(struct index_state *istate)
1688{
1689        switch (git_config_get_untracked_cache()) {
1690        case -1: /* keep: do nothing */
1691                break;
1692        case 0: /* false */
1693                remove_untracked_cache(istate);
1694                break;
1695        case 1: /* true */
1696                add_untracked_cache(istate);
1697                break;
1698        default: /* unknown value: do nothing */
1699                break;
1700        }
1701}
1702
1703static void tweak_split_index(struct index_state *istate)
1704{
1705        switch (git_config_get_split_index()) {
1706        case -1: /* unset: do nothing */
1707                break;
1708        case 0: /* false */
1709                remove_split_index(istate);
1710                break;
1711        case 1: /* true */
1712                add_split_index(istate);
1713                break;
1714        default: /* unknown value: do nothing */
1715                break;
1716        }
1717}
1718
1719static void post_read_index_from(struct index_state *istate)
1720{
1721        check_ce_order(istate);
1722        tweak_untracked_cache(istate);
1723        tweak_split_index(istate);
1724}
1725
1726/* remember to discard_cache() before reading a different cache! */
1727int do_read_index(struct index_state *istate, const char *path, int must_exist)
1728{
1729        int fd, i;
1730        struct stat st;
1731        unsigned long src_offset;
1732        struct cache_header *hdr;
1733        void *mmap;
1734        size_t mmap_size;
1735        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
1736
1737        if (istate->initialized)
1738                return istate->cache_nr;
1739
1740        istate->timestamp.sec = 0;
1741        istate->timestamp.nsec = 0;
1742        fd = open(path, O_RDONLY);
1743        if (fd < 0) {
1744                if (!must_exist && errno == ENOENT)
1745                        return 0;
1746                die_errno("%s: index file open failed", path);
1747        }
1748
1749        if (fstat(fd, &st))
1750                die_errno("cannot stat the open index");
1751
1752        mmap_size = xsize_t(st.st_size);
1753        if (mmap_size < sizeof(struct cache_header) + 20)
1754                die("index file smaller than expected");
1755
1756        mmap = xmmap(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0);
1757        if (mmap == MAP_FAILED)
1758                die_errno("unable to map index file");
1759        close(fd);
1760
1761        hdr = mmap;
1762        if (verify_hdr(hdr, mmap_size) < 0)
1763                goto unmap;
1764
1765        hashcpy(istate->sha1, (const unsigned char *)hdr + mmap_size - 20);
1766        istate->version = ntohl(hdr->hdr_version);
1767        istate->cache_nr = ntohl(hdr->hdr_entries);
1768        istate->cache_alloc = alloc_nr(istate->cache_nr);
1769        istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
1770        istate->initialized = 1;
1771
1772        if (istate->version == 4)
1773                previous_name = &previous_name_buf;
1774        else
1775                previous_name = NULL;
1776
1777        src_offset = sizeof(*hdr);
1778        for (i = 0; i < istate->cache_nr; i++) {
1779                struct ondisk_cache_entry *disk_ce;
1780                struct cache_entry *ce;
1781                unsigned long consumed;
1782
1783                disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1784                ce = create_from_disk(disk_ce, &consumed, previous_name);
1785                set_index_entry(istate, i, ce);
1786
1787                src_offset += consumed;
1788        }
1789        strbuf_release(&previous_name_buf);
1790        istate->timestamp.sec = st.st_mtime;
1791        istate->timestamp.nsec = ST_MTIME_NSEC(st);
1792
1793        while (src_offset <= mmap_size - 20 - 8) {
1794                /* After an array of active_nr index entries,
1795                 * there can be arbitrary number of extended
1796                 * sections, each of which is prefixed with
1797                 * extension name (4-byte) and section length
1798                 * in 4-byte network byte order.
1799                 */
1800                uint32_t extsize;
1801                memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1802                extsize = ntohl(extsize);
1803                if (read_index_extension(istate,
1804                                         (const char *) mmap + src_offset,
1805                                         (char *) mmap + src_offset + 8,
1806                                         extsize) < 0)
1807                        goto unmap;
1808                src_offset += 8;
1809                src_offset += extsize;
1810        }
1811        munmap(mmap, mmap_size);
1812        return istate->cache_nr;
1813
1814unmap:
1815        munmap(mmap, mmap_size);
1816        die("index file corrupt");
1817}
1818
1819/*
1820 * Signal that the shared index is used by updating its mtime.
1821 *
1822 * This way, shared index can be removed if they have not been used
1823 * for some time.
1824 */
1825static void freshen_shared_index(char *base_sha1_hex, int warn)
1826{
1827        char *shared_index = git_pathdup("sharedindex.%s", base_sha1_hex);
1828        if (!check_and_freshen_file(shared_index, 1) && warn)
1829                warning("could not freshen shared index '%s'", shared_index);
1830        free(shared_index);
1831}
1832
1833int read_index_from(struct index_state *istate, const char *path)
1834{
1835        struct split_index *split_index;
1836        int ret;
1837        char *base_sha1_hex;
1838        const char *base_path;
1839
1840        /* istate->initialized covers both .git/index and .git/sharedindex.xxx */
1841        if (istate->initialized)
1842                return istate->cache_nr;
1843
1844        ret = do_read_index(istate, path, 0);
1845
1846        split_index = istate->split_index;
1847        if (!split_index || is_null_sha1(split_index->base_sha1)) {
1848                post_read_index_from(istate);
1849                return ret;
1850        }
1851
1852        if (split_index->base)
1853                discard_index(split_index->base);
1854        else
1855                split_index->base = xcalloc(1, sizeof(*split_index->base));
1856
1857        base_sha1_hex = sha1_to_hex(split_index->base_sha1);
1858        base_path = git_path("sharedindex.%s", base_sha1_hex);
1859        ret = do_read_index(split_index->base, base_path, 1);
1860        if (hashcmp(split_index->base_sha1, split_index->base->sha1))
1861                die("broken index, expect %s in %s, got %s",
1862                    base_sha1_hex, base_path,
1863                    sha1_to_hex(split_index->base->sha1));
1864
1865        freshen_shared_index(base_sha1_hex, 0);
1866        merge_base_index(istate);
1867        post_read_index_from(istate);
1868        return ret;
1869}
1870
1871int is_index_unborn(struct index_state *istate)
1872{
1873        return (!istate->cache_nr && !istate->timestamp.sec);
1874}
1875
1876int discard_index(struct index_state *istate)
1877{
1878        int i;
1879
1880        unshare_split_index(istate, 1);
1881        for (i = 0; i < istate->cache_nr; i++)
1882                free(istate->cache[i]);
1883        resolve_undo_clear_index(istate);
1884        istate->cache_nr = 0;
1885        istate->cache_changed = 0;
1886        istate->timestamp.sec = 0;
1887        istate->timestamp.nsec = 0;
1888        free_name_hash(istate);
1889        cache_tree_free(&(istate->cache_tree));
1890        istate->initialized = 0;
1891        free(istate->cache);
1892        istate->cache = NULL;
1893        istate->cache_alloc = 0;
1894        discard_split_index(istate);
1895        free_untracked_cache(istate->untracked);
1896        istate->untracked = NULL;
1897        return 0;
1898}
1899
1900int unmerged_index(const struct index_state *istate)
1901{
1902        int i;
1903        for (i = 0; i < istate->cache_nr; i++) {
1904                if (ce_stage(istate->cache[i]))
1905                        return 1;
1906        }
1907        return 0;
1908}
1909
1910#define WRITE_BUFFER_SIZE 8192
1911static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1912static unsigned long write_buffer_len;
1913
1914static int ce_write_flush(git_SHA_CTX *context, int fd)
1915{
1916        unsigned int buffered = write_buffer_len;
1917        if (buffered) {
1918                git_SHA1_Update(context, write_buffer, buffered);
1919                if (write_in_full(fd, write_buffer, buffered) != buffered)
1920                        return -1;
1921                write_buffer_len = 0;
1922        }
1923        return 0;
1924}
1925
1926static int ce_write(git_SHA_CTX *context, int fd, void *data, unsigned int len)
1927{
1928        while (len) {
1929                unsigned int buffered = write_buffer_len;
1930                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1931                if (partial > len)
1932                        partial = len;
1933                memcpy(write_buffer + buffered, data, partial);
1934                buffered += partial;
1935                if (buffered == WRITE_BUFFER_SIZE) {
1936                        write_buffer_len = buffered;
1937                        if (ce_write_flush(context, fd))
1938                                return -1;
1939                        buffered = 0;
1940                }
1941                write_buffer_len = buffered;
1942                len -= partial;
1943                data = (char *) data + partial;
1944        }
1945        return 0;
1946}
1947
1948static int write_index_ext_header(git_SHA_CTX *context, int fd,
1949                                  unsigned int ext, unsigned int sz)
1950{
1951        ext = htonl(ext);
1952        sz = htonl(sz);
1953        return ((ce_write(context, fd, &ext, 4) < 0) ||
1954                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1955}
1956
1957static int ce_flush(git_SHA_CTX *context, int fd, unsigned char *sha1)
1958{
1959        unsigned int left = write_buffer_len;
1960
1961        if (left) {
1962                write_buffer_len = 0;
1963                git_SHA1_Update(context, write_buffer, left);
1964        }
1965
1966        /* Flush first if not enough space for SHA1 signature */
1967        if (left + 20 > WRITE_BUFFER_SIZE) {
1968                if (write_in_full(fd, write_buffer, left) != left)
1969                        return -1;
1970                left = 0;
1971        }
1972
1973        /* Append the SHA1 signature at the end */
1974        git_SHA1_Final(write_buffer + left, context);
1975        hashcpy(sha1, write_buffer + left);
1976        left += 20;
1977        return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1978}
1979
1980static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1981{
1982        /*
1983         * The only thing we care about in this function is to smudge the
1984         * falsely clean entry due to touch-update-touch race, so we leave
1985         * everything else as they are.  We are called for entries whose
1986         * ce_stat_data.sd_mtime match the index file mtime.
1987         *
1988         * Note that this actually does not do much for gitlinks, for
1989         * which ce_match_stat_basic() always goes to the actual
1990         * contents.  The caller checks with is_racy_timestamp() which
1991         * always says "no" for gitlinks, so we are not called for them ;-)
1992         */
1993        struct stat st;
1994
1995        if (lstat(ce->name, &st) < 0)
1996                return;
1997        if (ce_match_stat_basic(ce, &st))
1998                return;
1999        if (ce_modified_check_fs(ce, &st)) {
2000                /* This is "racily clean"; smudge it.  Note that this
2001                 * is a tricky code.  At first glance, it may appear
2002                 * that it can break with this sequence:
2003                 *
2004                 * $ echo xyzzy >frotz
2005                 * $ git-update-index --add frotz
2006                 * $ : >frotz
2007                 * $ sleep 3
2008                 * $ echo filfre >nitfol
2009                 * $ git-update-index --add nitfol
2010                 *
2011                 * but it does not.  When the second update-index runs,
2012                 * it notices that the entry "frotz" has the same timestamp
2013                 * as index, and if we were to smudge it by resetting its
2014                 * size to zero here, then the object name recorded
2015                 * in index is the 6-byte file but the cached stat information
2016                 * becomes zero --- which would then match what we would
2017                 * obtain from the filesystem next time we stat("frotz").
2018                 *
2019                 * However, the second update-index, before calling
2020                 * this function, notices that the cached size is 6
2021                 * bytes and what is on the filesystem is an empty
2022                 * file, and never calls us, so the cached size information
2023                 * for "frotz" stays 6 which does not match the filesystem.
2024                 */
2025                ce->ce_stat_data.sd_size = 0;
2026        }
2027}
2028
2029/* Copy miscellaneous fields but not the name */
2030static char *copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
2031                                       struct cache_entry *ce)
2032{
2033        short flags;
2034
2035        ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec);
2036        ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec);
2037        ondisk->ctime.nsec = htonl(ce->ce_stat_data.sd_ctime.nsec);
2038        ondisk->mtime.nsec = htonl(ce->ce_stat_data.sd_mtime.nsec);
2039        ondisk->dev  = htonl(ce->ce_stat_data.sd_dev);
2040        ondisk->ino  = htonl(ce->ce_stat_data.sd_ino);
2041        ondisk->mode = htonl(ce->ce_mode);
2042        ondisk->uid  = htonl(ce->ce_stat_data.sd_uid);
2043        ondisk->gid  = htonl(ce->ce_stat_data.sd_gid);
2044        ondisk->size = htonl(ce->ce_stat_data.sd_size);
2045        hashcpy(ondisk->sha1, ce->oid.hash);
2046
2047        flags = ce->ce_flags & ~CE_NAMEMASK;
2048        flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
2049        ondisk->flags = htons(flags);
2050        if (ce->ce_flags & CE_EXTENDED) {
2051                struct ondisk_cache_entry_extended *ondisk2;
2052                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
2053                ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
2054                return ondisk2->name;
2055        }
2056        else {
2057                return ondisk->name;
2058        }
2059}
2060
2061static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
2062                          struct strbuf *previous_name)
2063{
2064        int size;
2065        struct ondisk_cache_entry *ondisk;
2066        int saved_namelen = saved_namelen; /* compiler workaround */
2067        char *name;
2068        int result;
2069
2070        if (ce->ce_flags & CE_STRIP_NAME) {
2071                saved_namelen = ce_namelen(ce);
2072                ce->ce_namelen = 0;
2073        }
2074
2075        if (!previous_name) {
2076                size = ondisk_ce_size(ce);
2077                ondisk = xcalloc(1, size);
2078                name = copy_cache_entry_to_ondisk(ondisk, ce);
2079                memcpy(name, ce->name, ce_namelen(ce));
2080        } else {
2081                int common, to_remove, prefix_size;
2082                unsigned char to_remove_vi[16];
2083                for (common = 0;
2084                     (ce->name[common] &&
2085                      common < previous_name->len &&
2086                      ce->name[common] == previous_name->buf[common]);
2087                     common++)
2088                        ; /* still matching */
2089                to_remove = previous_name->len - common;
2090                prefix_size = encode_varint(to_remove, to_remove_vi);
2091
2092                if (ce->ce_flags & CE_EXTENDED)
2093                        size = offsetof(struct ondisk_cache_entry_extended, name);
2094                else
2095                        size = offsetof(struct ondisk_cache_entry, name);
2096                size += prefix_size + (ce_namelen(ce) - common + 1);
2097
2098                ondisk = xcalloc(1, size);
2099                name = copy_cache_entry_to_ondisk(ondisk, ce);
2100                memcpy(name, to_remove_vi, prefix_size);
2101                memcpy(name + prefix_size, ce->name + common, ce_namelen(ce) - common);
2102
2103                strbuf_splice(previous_name, common, to_remove,
2104                              ce->name + common, ce_namelen(ce) - common);
2105        }
2106        if (ce->ce_flags & CE_STRIP_NAME) {
2107                ce->ce_namelen = saved_namelen;
2108                ce->ce_flags &= ~CE_STRIP_NAME;
2109        }
2110
2111        result = ce_write(c, fd, ondisk, size);
2112        free(ondisk);
2113        return result;
2114}
2115
2116/*
2117 * This function verifies if index_state has the correct sha1 of the
2118 * index file.  Don't die if we have any other failure, just return 0.
2119 */
2120static int verify_index_from(const struct index_state *istate, const char *path)
2121{
2122        int fd;
2123        ssize_t n;
2124        struct stat st;
2125        unsigned char sha1[20];
2126
2127        if (!istate->initialized)
2128                return 0;
2129
2130        fd = open(path, O_RDONLY);
2131        if (fd < 0)
2132                return 0;
2133
2134        if (fstat(fd, &st))
2135                goto out;
2136
2137        if (st.st_size < sizeof(struct cache_header) + 20)
2138                goto out;
2139
2140        n = pread_in_full(fd, sha1, 20, st.st_size - 20);
2141        if (n != 20)
2142                goto out;
2143
2144        if (hashcmp(istate->sha1, sha1))
2145                goto out;
2146
2147        close(fd);
2148        return 1;
2149
2150out:
2151        close(fd);
2152        return 0;
2153}
2154
2155static int verify_index(const struct index_state *istate)
2156{
2157        return verify_index_from(istate, get_index_file());
2158}
2159
2160static int has_racy_timestamp(struct index_state *istate)
2161{
2162        int entries = istate->cache_nr;
2163        int i;
2164
2165        for (i = 0; i < entries; i++) {
2166                struct cache_entry *ce = istate->cache[i];
2167                if (is_racy_timestamp(istate, ce))
2168                        return 1;
2169        }
2170        return 0;
2171}
2172
2173/*
2174 * Opportunistically update the index but do not complain if we can't
2175 */
2176void update_index_if_able(struct index_state *istate, struct lock_file *lockfile)
2177{
2178        if ((istate->cache_changed || has_racy_timestamp(istate)) &&
2179            verify_index(istate) &&
2180            write_locked_index(istate, lockfile, COMMIT_LOCK))
2181                rollback_lock_file(lockfile);
2182}
2183
2184static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
2185                          int strip_extensions)
2186{
2187        int newfd = tempfile->fd;
2188        git_SHA_CTX c;
2189        struct cache_header hdr;
2190        int i, err, removed, extended, hdr_version;
2191        struct cache_entry **cache = istate->cache;
2192        int entries = istate->cache_nr;
2193        struct stat st;
2194        struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
2195        int drop_cache_tree = 0;
2196
2197        for (i = removed = extended = 0; i < entries; i++) {
2198                if (cache[i]->ce_flags & CE_REMOVE)
2199                        removed++;
2200
2201                /* reduce extended entries if possible */
2202                cache[i]->ce_flags &= ~CE_EXTENDED;
2203                if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) {
2204                        extended++;
2205                        cache[i]->ce_flags |= CE_EXTENDED;
2206                }
2207        }
2208
2209        if (!istate->version) {
2210                istate->version = get_index_format_default();
2211                if (getenv("GIT_TEST_SPLIT_INDEX"))
2212                        init_split_index(istate);
2213        }
2214
2215        /* demote version 3 to version 2 when the latter suffices */
2216        if (istate->version == 3 || istate->version == 2)
2217                istate->version = extended ? 3 : 2;
2218
2219        hdr_version = istate->version;
2220
2221        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
2222        hdr.hdr_version = htonl(hdr_version);
2223        hdr.hdr_entries = htonl(entries - removed);
2224
2225        git_SHA1_Init(&c);
2226        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
2227                return -1;
2228
2229        previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
2230        for (i = 0; i < entries; i++) {
2231                struct cache_entry *ce = cache[i];
2232                if (ce->ce_flags & CE_REMOVE)
2233                        continue;
2234                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
2235                        ce_smudge_racily_clean_entry(ce);
2236                if (is_null_oid(&ce->oid)) {
2237                        static const char msg[] = "cache entry has null sha1: %s";
2238                        static int allow = -1;
2239
2240                        if (allow < 0)
2241                                allow = git_env_bool("GIT_ALLOW_NULL_SHA1", 0);
2242                        if (allow)
2243                                warning(msg, ce->name);
2244                        else
2245                                return error(msg, ce->name);
2246
2247                        drop_cache_tree = 1;
2248                }
2249                if (ce_write_entry(&c, newfd, ce, previous_name) < 0)
2250                        return -1;
2251        }
2252        strbuf_release(&previous_name_buf);
2253
2254        /* Write extension data here */
2255        if (!strip_extensions && istate->split_index) {
2256                struct strbuf sb = STRBUF_INIT;
2257
2258                err = write_link_extension(&sb, istate) < 0 ||
2259                        write_index_ext_header(&c, newfd, CACHE_EXT_LINK,
2260                                               sb.len) < 0 ||
2261                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2262                strbuf_release(&sb);
2263                if (err)
2264                        return -1;
2265        }
2266        if (!strip_extensions && !drop_cache_tree && istate->cache_tree) {
2267                struct strbuf sb = STRBUF_INIT;
2268
2269                cache_tree_write(&sb, istate->cache_tree);
2270                err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
2271                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2272                strbuf_release(&sb);
2273                if (err)
2274                        return -1;
2275        }
2276        if (!strip_extensions && istate->resolve_undo) {
2277                struct strbuf sb = STRBUF_INIT;
2278
2279                resolve_undo_write(&sb, istate->resolve_undo);
2280                err = write_index_ext_header(&c, newfd, CACHE_EXT_RESOLVE_UNDO,
2281                                             sb.len) < 0
2282                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
2283                strbuf_release(&sb);
2284                if (err)
2285                        return -1;
2286        }
2287        if (!strip_extensions && istate->untracked) {
2288                struct strbuf sb = STRBUF_INIT;
2289
2290                write_untracked_extension(&sb, istate->untracked);
2291                err = write_index_ext_header(&c, newfd, CACHE_EXT_UNTRACKED,
2292                                             sb.len) < 0 ||
2293                        ce_write(&c, newfd, sb.buf, sb.len) < 0;
2294                strbuf_release(&sb);
2295                if (err)
2296                        return -1;
2297        }
2298
2299        if (ce_flush(&c, newfd, istate->sha1))
2300                return -1;
2301        if (close_tempfile(tempfile))
2302                return error(_("could not close '%s'"), tempfile->filename.buf);
2303        if (stat(tempfile->filename.buf, &st))
2304                return -1;
2305        istate->timestamp.sec = (unsigned int)st.st_mtime;
2306        istate->timestamp.nsec = ST_MTIME_NSEC(st);
2307        return 0;
2308}
2309
2310void set_alternate_index_output(const char *name)
2311{
2312        alternate_index_output = name;
2313}
2314
2315static int commit_locked_index(struct lock_file *lk)
2316{
2317        if (alternate_index_output)
2318                return commit_lock_file_to(lk, alternate_index_output);
2319        else
2320                return commit_lock_file(lk);
2321}
2322
2323static int do_write_locked_index(struct index_state *istate, struct lock_file *lock,
2324                                 unsigned flags)
2325{
2326        int ret = do_write_index(istate, &lock->tempfile, 0);
2327        if (ret)
2328                return ret;
2329        assert((flags & (COMMIT_LOCK | CLOSE_LOCK)) !=
2330               (COMMIT_LOCK | CLOSE_LOCK));
2331        if (flags & COMMIT_LOCK)
2332                return commit_locked_index(lock);
2333        else if (flags & CLOSE_LOCK)
2334                return close_lock_file(lock);
2335        else
2336                return ret;
2337}
2338
2339static int write_split_index(struct index_state *istate,
2340                             struct lock_file *lock,
2341                             unsigned flags)
2342{
2343        int ret;
2344        prepare_to_write_split_index(istate);
2345        ret = do_write_locked_index(istate, lock, flags);
2346        finish_writing_split_index(istate);
2347        return ret;
2348}
2349
2350static const char *shared_index_expire = "2.weeks.ago";
2351
2352static unsigned long get_shared_index_expire_date(void)
2353{
2354        static unsigned long shared_index_expire_date;
2355        static int shared_index_expire_date_prepared;
2356
2357        if (!shared_index_expire_date_prepared) {
2358                git_config_get_expiry("splitindex.sharedindexexpire",
2359                                      &shared_index_expire);
2360                shared_index_expire_date = approxidate(shared_index_expire);
2361                shared_index_expire_date_prepared = 1;
2362        }
2363
2364        return shared_index_expire_date;
2365}
2366
2367static int should_delete_shared_index(const char *shared_index_path)
2368{
2369        struct stat st;
2370        unsigned long expiration;
2371
2372        /* Check timestamp */
2373        expiration = get_shared_index_expire_date();
2374        if (!expiration)
2375                return 0;
2376        if (stat(shared_index_path, &st))
2377                return error_errno(_("could not stat '%s'"), shared_index_path);
2378        if (st.st_mtime > expiration)
2379                return 0;
2380
2381        return 1;
2382}
2383
2384static int clean_shared_index_files(const char *current_hex)
2385{
2386        struct dirent *de;
2387        DIR *dir = opendir(get_git_dir());
2388
2389        if (!dir)
2390                return error_errno(_("unable to open git dir: %s"), get_git_dir());
2391
2392        while ((de = readdir(dir)) != NULL) {
2393                const char *sha1_hex;
2394                const char *shared_index_path;
2395                if (!skip_prefix(de->d_name, "sharedindex.", &sha1_hex))
2396                        continue;
2397                if (!strcmp(sha1_hex, current_hex))
2398                        continue;
2399                shared_index_path = git_path("%s", de->d_name);
2400                if (should_delete_shared_index(shared_index_path) > 0 &&
2401                    unlink(shared_index_path))
2402                        warning_errno(_("unable to unlink: %s"), shared_index_path);
2403        }
2404        closedir(dir);
2405
2406        return 0;
2407}
2408
2409static struct tempfile temporary_sharedindex;
2410
2411static int write_shared_index(struct index_state *istate,
2412                              struct lock_file *lock, unsigned flags)
2413{
2414        struct split_index *si = istate->split_index;
2415        int fd, ret;
2416
2417        fd = mks_tempfile(&temporary_sharedindex, git_path("sharedindex_XXXXXX"));
2418        if (fd < 0) {
2419                hashclr(si->base_sha1);
2420                return do_write_locked_index(istate, lock, flags);
2421        }
2422        move_cache_to_base_index(istate);
2423        ret = do_write_index(si->base, &temporary_sharedindex, 1);
2424        if (ret) {
2425                delete_tempfile(&temporary_sharedindex);
2426                return ret;
2427        }
2428        ret = rename_tempfile(&temporary_sharedindex,
2429                              git_path("sharedindex.%s", sha1_to_hex(si->base->sha1)));
2430        if (!ret) {
2431                hashcpy(si->base_sha1, si->base->sha1);
2432                clean_shared_index_files(sha1_to_hex(si->base->sha1));
2433        }
2434
2435        return ret;
2436}
2437
2438static const int default_max_percent_split_change = 20;
2439
2440static int too_many_not_shared_entries(struct index_state *istate)
2441{
2442        int i, not_shared = 0;
2443        int max_split = git_config_get_max_percent_split_change();
2444
2445        switch (max_split) {
2446        case -1:
2447                /* not or badly configured: use the default value */
2448                max_split = default_max_percent_split_change;
2449                break;
2450        case 0:
2451                return 1; /* 0% means always write a new shared index */
2452        case 100:
2453                return 0; /* 100% means never write a new shared index */
2454        default:
2455                break; /* just use the configured value */
2456        }
2457
2458        /* Count not shared entries */
2459        for (i = 0; i < istate->cache_nr; i++) {
2460                struct cache_entry *ce = istate->cache[i];
2461                if (!ce->index)
2462                        not_shared++;
2463        }
2464
2465        return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100;
2466}
2467
2468int write_locked_index(struct index_state *istate, struct lock_file *lock,
2469                       unsigned flags)
2470{
2471        int new_shared_index, ret;
2472        struct split_index *si = istate->split_index;
2473
2474        if (!si || alternate_index_output ||
2475            (istate->cache_changed & ~EXTMASK)) {
2476                if (si)
2477                        hashclr(si->base_sha1);
2478                return do_write_locked_index(istate, lock, flags);
2479        }
2480
2481        if (getenv("GIT_TEST_SPLIT_INDEX")) {
2482                int v = si->base_sha1[0];
2483                if ((v & 15) < 6)
2484                        istate->cache_changed |= SPLIT_INDEX_ORDERED;
2485        }
2486        if (too_many_not_shared_entries(istate))
2487                istate->cache_changed |= SPLIT_INDEX_ORDERED;
2488
2489        new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED;
2490
2491        if (new_shared_index) {
2492                ret = write_shared_index(istate, lock, flags);
2493                if (ret)
2494                        return ret;
2495        }
2496
2497        ret = write_split_index(istate, lock, flags);
2498
2499        /* Freshen the shared index only if the split-index was written */
2500        if (!ret && !new_shared_index)
2501                freshen_shared_index(sha1_to_hex(si->base_sha1), 1);
2502
2503        return ret;
2504}
2505
2506/*
2507 * Read the index file that is potentially unmerged into given
2508 * index_state, dropping any unmerged entries.  Returns true if
2509 * the index is unmerged.  Callers who want to refuse to work
2510 * from an unmerged state can call this and check its return value,
2511 * instead of calling read_cache().
2512 */
2513int read_index_unmerged(struct index_state *istate)
2514{
2515        int i;
2516        int unmerged = 0;
2517
2518        read_index(istate);
2519        for (i = 0; i < istate->cache_nr; i++) {
2520                struct cache_entry *ce = istate->cache[i];
2521                struct cache_entry *new_ce;
2522                int size, len;
2523
2524                if (!ce_stage(ce))
2525                        continue;
2526                unmerged = 1;
2527                len = ce_namelen(ce);
2528                size = cache_entry_size(len);
2529                new_ce = xcalloc(1, size);
2530                memcpy(new_ce->name, ce->name, len);
2531                new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED;
2532                new_ce->ce_namelen = len;
2533                new_ce->ce_mode = ce->ce_mode;
2534                if (add_index_entry(istate, new_ce, 0))
2535                        return error("%s: cannot drop to stage #0",
2536                                     new_ce->name);
2537        }
2538        return unmerged;
2539}
2540
2541/*
2542 * Returns 1 if the path is an "other" path with respect to
2543 * the index; that is, the path is not mentioned in the index at all,
2544 * either as a file, a directory with some files in the index,
2545 * or as an unmerged entry.
2546 *
2547 * We helpfully remove a trailing "/" from directories so that
2548 * the output of read_directory can be used as-is.
2549 */
2550int index_name_is_other(const struct index_state *istate, const char *name,
2551                int namelen)
2552{
2553        int pos;
2554        if (namelen && name[namelen - 1] == '/')
2555                namelen--;
2556        pos = index_name_pos(istate, name, namelen);
2557        if (0 <= pos)
2558                return 0;       /* exact match */
2559        pos = -pos - 1;
2560        if (pos < istate->cache_nr) {
2561                struct cache_entry *ce = istate->cache[pos];
2562                if (ce_namelen(ce) == namelen &&
2563                    !memcmp(ce->name, name, namelen))
2564                        return 0; /* Yup, this one exists unmerged */
2565        }
2566        return 1;
2567}
2568
2569void *read_blob_data_from_index(const struct index_state *istate,
2570                                const char *path, unsigned long *size)
2571{
2572        int pos, len;
2573        unsigned long sz;
2574        enum object_type type;
2575        void *data;
2576
2577        len = strlen(path);
2578        pos = index_name_pos(istate, path, len);
2579        if (pos < 0) {
2580                /*
2581                 * We might be in the middle of a merge, in which
2582                 * case we would read stage #2 (ours).
2583                 */
2584                int i;
2585                for (i = -pos - 1;
2586                     (pos < 0 && i < istate->cache_nr &&
2587                      !strcmp(istate->cache[i]->name, path));
2588                     i++)
2589                        if (ce_stage(istate->cache[i]) == 2)
2590                                pos = i;
2591        }
2592        if (pos < 0)
2593                return NULL;
2594        data = read_sha1_file(istate->cache[pos]->oid.hash, &type, &sz);
2595        if (!data || type != OBJ_BLOB) {
2596                free(data);
2597                return NULL;
2598        }
2599        if (size)
2600                *size = sz;
2601        return data;
2602}
2603
2604void stat_validity_clear(struct stat_validity *sv)
2605{
2606        free(sv->sd);
2607        sv->sd = NULL;
2608}
2609
2610int stat_validity_check(struct stat_validity *sv, const char *path)
2611{
2612        struct stat st;
2613
2614        if (stat(path, &st) < 0)
2615                return sv->sd == NULL;
2616        if (!sv->sd)
2617                return 0;
2618        return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st);
2619}
2620
2621void stat_validity_update(struct stat_validity *sv, int fd)
2622{
2623        struct stat st;
2624
2625        if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode))
2626                stat_validity_clear(sv);
2627        else {
2628                if (!sv->sd)
2629                        sv->sd = xcalloc(1, sizeof(struct stat_data));
2630                fill_stat_data(sv->sd, &st);
2631        }
2632}
2633
2634void move_index_extensions(struct index_state *dst, struct index_state *src)
2635{
2636        dst->untracked = src->untracked;
2637        src->untracked = NULL;
2638}