fa30a0f88577be6ec33832ea34f8a71e7ba6b0ea
   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 "cache-tree.h"
   9#include "refs.h"
  10#include "dir.h"
  11#include "tree.h"
  12#include "commit.h"
  13#include "diff.h"
  14#include "diffcore.h"
  15#include "revision.h"
  16#include "blob.h"
  17
  18/* Index extensions.
  19 *
  20 * The first letter should be 'A'..'Z' for extensions that are not
  21 * necessary for a correct operation (i.e. optimization data).
  22 * When new extensions are added that _needs_ to be understood in
  23 * order to correctly interpret the index file, pick character that
  24 * is outside the range, to cause the reader to abort.
  25 */
  26
  27#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  28#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  29
  30struct index_state the_index;
  31
  32static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  33{
  34        istate->cache[nr] = ce;
  35        add_name_hash(istate, ce);
  36}
  37
  38static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  39{
  40        struct cache_entry *old = istate->cache[nr];
  41
  42        remove_name_hash(old);
  43        set_index_entry(istate, nr, ce);
  44        istate->cache_changed = 1;
  45}
  46
  47void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
  48{
  49        struct cache_entry *old = istate->cache[nr], *new;
  50        int namelen = strlen(new_name);
  51
  52        new = xmalloc(cache_entry_size(namelen));
  53        copy_cache_entry(new, old);
  54        new->ce_flags &= ~(CE_STATE_MASK | CE_NAMEMASK);
  55        new->ce_flags |= (namelen >= CE_NAMEMASK ? CE_NAMEMASK : namelen);
  56        memcpy(new->name, new_name, namelen + 1);
  57
  58        cache_tree_invalidate_path(istate->cache_tree, old->name);
  59        remove_index_entry_at(istate, nr);
  60        add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
  61}
  62
  63/*
  64 * This only updates the "non-critical" parts of the directory
  65 * cache, ie the parts that aren't tracked by GIT, and only used
  66 * to validate the cache.
  67 */
  68void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  69{
  70        ce->ce_ctime = st->st_ctime;
  71        ce->ce_mtime = st->st_mtime;
  72        ce->ce_dev = st->st_dev;
  73        ce->ce_ino = st->st_ino;
  74        ce->ce_uid = st->st_uid;
  75        ce->ce_gid = st->st_gid;
  76        ce->ce_size = st->st_size;
  77
  78        if (assume_unchanged)
  79                ce->ce_flags |= CE_VALID;
  80
  81        if (S_ISREG(st->st_mode))
  82                ce_mark_uptodate(ce);
  83}
  84
  85static int ce_compare_data(struct cache_entry *ce, struct stat *st)
  86{
  87        int match = -1;
  88        int fd = open(ce->name, O_RDONLY);
  89
  90        if (fd >= 0) {
  91                unsigned char sha1[20];
  92                if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
  93                        match = hashcmp(sha1, ce->sha1);
  94                /* index_fd() closed the file descriptor already */
  95        }
  96        return match;
  97}
  98
  99static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
 100{
 101        int match = -1;
 102        char *target;
 103        void *buffer;
 104        unsigned long size;
 105        enum object_type type;
 106        int len;
 107
 108        target = xmalloc(expected_size);
 109        len = readlink(ce->name, target, expected_size);
 110        if (len != expected_size) {
 111                free(target);
 112                return -1;
 113        }
 114        buffer = read_sha1_file(ce->sha1, &type, &size);
 115        if (!buffer) {
 116                free(target);
 117                return -1;
 118        }
 119        if (size == expected_size)
 120                match = memcmp(buffer, target, size);
 121        free(buffer);
 122        free(target);
 123        return match;
 124}
 125
 126static int ce_compare_gitlink(struct cache_entry *ce)
 127{
 128        unsigned char sha1[20];
 129
 130        /*
 131         * We don't actually require that the .git directory
 132         * under GITLINK directory be a valid git directory. It
 133         * might even be missing (in case nobody populated that
 134         * sub-project).
 135         *
 136         * If so, we consider it always to match.
 137         */
 138        if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 139                return 0;
 140        return hashcmp(sha1, ce->sha1);
 141}
 142
 143static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 144{
 145        switch (st->st_mode & S_IFMT) {
 146        case S_IFREG:
 147                if (ce_compare_data(ce, st))
 148                        return DATA_CHANGED;
 149                break;
 150        case S_IFLNK:
 151                if (ce_compare_link(ce, xsize_t(st->st_size)))
 152                        return DATA_CHANGED;
 153                break;
 154        case S_IFDIR:
 155                if (S_ISGITLINK(ce->ce_mode))
 156                        return ce_compare_gitlink(ce) ? DATA_CHANGED : 0;
 157        default:
 158                return TYPE_CHANGED;
 159        }
 160        return 0;
 161}
 162
 163int is_empty_blob_sha1(const unsigned char *sha1)
 164{
 165        static const unsigned char empty_blob_sha1[20] = {
 166                0xe6,0x9d,0xe2,0x9b,0xb2,0xd1,0xd6,0x43,0x4b,0x8b,
 167                0x29,0xae,0x77,0x5a,0xd8,0xc2,0xe4,0x8c,0x53,0x91
 168        };
 169
 170        return !hashcmp(sha1, empty_blob_sha1);
 171}
 172
 173static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 174{
 175        unsigned int changed = 0;
 176
 177        if (ce->ce_flags & CE_REMOVE)
 178                return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 179
 180        switch (ce->ce_mode & S_IFMT) {
 181        case S_IFREG:
 182                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 183                /* We consider only the owner x bit to be relevant for
 184                 * "mode changes"
 185                 */
 186                if (trust_executable_bit &&
 187                    (0100 & (ce->ce_mode ^ st->st_mode)))
 188                        changed |= MODE_CHANGED;
 189                break;
 190        case S_IFLNK:
 191                if (!S_ISLNK(st->st_mode) &&
 192                    (has_symlinks || !S_ISREG(st->st_mode)))
 193                        changed |= TYPE_CHANGED;
 194                break;
 195        case S_IFGITLINK:
 196                /* We ignore most of the st_xxx fields for gitlinks */
 197                if (!S_ISDIR(st->st_mode))
 198                        changed |= TYPE_CHANGED;
 199                else if (ce_compare_gitlink(ce))
 200                        changed |= DATA_CHANGED;
 201                return changed;
 202        default:
 203                die("internal error: ce_mode is %o", ce->ce_mode);
 204        }
 205        if (ce->ce_mtime != (unsigned int) st->st_mtime)
 206                changed |= MTIME_CHANGED;
 207        if (trust_ctime && ce->ce_ctime != (unsigned int) st->st_ctime)
 208                changed |= CTIME_CHANGED;
 209
 210        if (ce->ce_uid != (unsigned int) st->st_uid ||
 211            ce->ce_gid != (unsigned int) st->st_gid)
 212                changed |= OWNER_CHANGED;
 213        if (ce->ce_ino != (unsigned int) st->st_ino)
 214                changed |= INODE_CHANGED;
 215
 216#ifdef USE_STDEV
 217        /*
 218         * st_dev breaks on network filesystems where different
 219         * clients will have different views of what "device"
 220         * the filesystem is on
 221         */
 222        if (ce->ce_dev != (unsigned int) st->st_dev)
 223                changed |= INODE_CHANGED;
 224#endif
 225
 226        if (ce->ce_size != (unsigned int) st->st_size)
 227                changed |= DATA_CHANGED;
 228
 229        /* Racily smudged entry? */
 230        if (!ce->ce_size) {
 231                if (!is_empty_blob_sha1(ce->sha1))
 232                        changed |= DATA_CHANGED;
 233        }
 234
 235        return changed;
 236}
 237
 238static int is_racy_timestamp(const struct index_state *istate, struct cache_entry *ce)
 239{
 240        return (!S_ISGITLINK(ce->ce_mode) &&
 241                istate->timestamp &&
 242                ((unsigned int)istate->timestamp) <= ce->ce_mtime);
 243}
 244
 245int ie_match_stat(const struct index_state *istate,
 246                  struct cache_entry *ce, struct stat *st,
 247                  unsigned int options)
 248{
 249        unsigned int changed;
 250        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 251        int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 252
 253        /*
 254         * If it's marked as always valid in the index, it's
 255         * valid whatever the checked-out copy says.
 256         */
 257        if (!ignore_valid && (ce->ce_flags & CE_VALID))
 258                return 0;
 259
 260        changed = ce_match_stat_basic(ce, st);
 261
 262        /*
 263         * Within 1 second of this sequence:
 264         *      echo xyzzy >file && git-update-index --add file
 265         * running this command:
 266         *      echo frotz >file
 267         * would give a falsely clean cache entry.  The mtime and
 268         * length match the cache, and other stat fields do not change.
 269         *
 270         * We could detect this at update-index time (the cache entry
 271         * being registered/updated records the same time as "now")
 272         * and delay the return from git-update-index, but that would
 273         * effectively mean we can make at most one commit per second,
 274         * which is not acceptable.  Instead, we check cache entries
 275         * whose mtime are the same as the index file timestamp more
 276         * carefully than others.
 277         */
 278        if (!changed && is_racy_timestamp(istate, ce)) {
 279                if (assume_racy_is_modified)
 280                        changed |= DATA_CHANGED;
 281                else
 282                        changed |= ce_modified_check_fs(ce, st);
 283        }
 284
 285        return changed;
 286}
 287
 288int ie_modified(const struct index_state *istate,
 289                struct cache_entry *ce, struct stat *st, unsigned int options)
 290{
 291        int changed, changed_fs;
 292
 293        changed = ie_match_stat(istate, ce, st, options);
 294        if (!changed)
 295                return 0;
 296        /*
 297         * If the mode or type has changed, there's no point in trying
 298         * to refresh the entry - it's not going to match
 299         */
 300        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 301                return changed;
 302
 303        /*
 304         * Immediately after read-tree or update-index --cacheinfo,
 305         * the length field is zero, as we have never even read the
 306         * lstat(2) information once, and we cannot trust DATA_CHANGED
 307         * returned by ie_match_stat() which in turn was returned by
 308         * ce_match_stat_basic() to signal that the filesize of the
 309         * blob changed.  We have to actually go to the filesystem to
 310         * see if the contents match, and if so, should answer "unchanged".
 311         *
 312         * The logic does not apply to gitlinks, as ce_match_stat_basic()
 313         * already has checked the actual HEAD from the filesystem in the
 314         * subproject.  If ie_match_stat() already said it is different,
 315         * then we know it is.
 316         */
 317        if ((changed & DATA_CHANGED) &&
 318            (S_ISGITLINK(ce->ce_mode) || ce->ce_size != 0))
 319                return changed;
 320
 321        changed_fs = ce_modified_check_fs(ce, st);
 322        if (changed_fs)
 323                return changed | changed_fs;
 324        return 0;
 325}
 326
 327int base_name_compare(const char *name1, int len1, int mode1,
 328                      const char *name2, int len2, int mode2)
 329{
 330        unsigned char c1, c2;
 331        int len = len1 < len2 ? len1 : len2;
 332        int cmp;
 333
 334        cmp = memcmp(name1, name2, len);
 335        if (cmp)
 336                return cmp;
 337        c1 = name1[len];
 338        c2 = name2[len];
 339        if (!c1 && S_ISDIR(mode1))
 340                c1 = '/';
 341        if (!c2 && S_ISDIR(mode2))
 342                c2 = '/';
 343        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 344}
 345
 346/*
 347 * df_name_compare() is identical to base_name_compare(), except it
 348 * compares conflicting directory/file entries as equal. Note that
 349 * while a directory name compares as equal to a regular file, they
 350 * then individually compare _differently_ to a filename that has
 351 * a dot after the basename (because '\0' < '.' < '/').
 352 *
 353 * This is used by routines that want to traverse the git namespace
 354 * but then handle conflicting entries together when possible.
 355 */
 356int df_name_compare(const char *name1, int len1, int mode1,
 357                    const char *name2, int len2, int mode2)
 358{
 359        int len = len1 < len2 ? len1 : len2, cmp;
 360        unsigned char c1, c2;
 361
 362        cmp = memcmp(name1, name2, len);
 363        if (cmp)
 364                return cmp;
 365        /* Directories and files compare equal (same length, same name) */
 366        if (len1 == len2)
 367                return 0;
 368        c1 = name1[len];
 369        if (!c1 && S_ISDIR(mode1))
 370                c1 = '/';
 371        c2 = name2[len];
 372        if (!c2 && S_ISDIR(mode2))
 373                c2 = '/';
 374        if (c1 == '/' && !c2)
 375                return 0;
 376        if (c2 == '/' && !c1)
 377                return 0;
 378        return c1 - c2;
 379}
 380
 381int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 382{
 383        int len1 = flags1 & CE_NAMEMASK;
 384        int len2 = flags2 & CE_NAMEMASK;
 385        int len = len1 < len2 ? len1 : len2;
 386        int cmp;
 387
 388        cmp = memcmp(name1, name2, len);
 389        if (cmp)
 390                return cmp;
 391        if (len1 < len2)
 392                return -1;
 393        if (len1 > len2)
 394                return 1;
 395
 396        /* Compare stages  */
 397        flags1 &= CE_STAGEMASK;
 398        flags2 &= CE_STAGEMASK;
 399
 400        if (flags1 < flags2)
 401                return -1;
 402        if (flags1 > flags2)
 403                return 1;
 404        return 0;
 405}
 406
 407int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 408{
 409        int first, last;
 410
 411        first = 0;
 412        last = istate->cache_nr;
 413        while (last > first) {
 414                int next = (last + first) >> 1;
 415                struct cache_entry *ce = istate->cache[next];
 416                int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
 417                if (!cmp)
 418                        return next;
 419                if (cmp < 0) {
 420                        last = next;
 421                        continue;
 422                }
 423                first = next+1;
 424        }
 425        return -first-1;
 426}
 427
 428/* Remove entry, return true if there are more entries to go.. */
 429int remove_index_entry_at(struct index_state *istate, int pos)
 430{
 431        struct cache_entry *ce = istate->cache[pos];
 432
 433        remove_name_hash(ce);
 434        istate->cache_changed = 1;
 435        istate->cache_nr--;
 436        if (pos >= istate->cache_nr)
 437                return 0;
 438        memmove(istate->cache + pos,
 439                istate->cache + pos + 1,
 440                (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 441        return 1;
 442}
 443
 444int remove_file_from_index(struct index_state *istate, const char *path)
 445{
 446        int pos = index_name_pos(istate, path, strlen(path));
 447        if (pos < 0)
 448                pos = -pos-1;
 449        cache_tree_invalidate_path(istate->cache_tree, path);
 450        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 451                remove_index_entry_at(istate, pos);
 452        return 0;
 453}
 454
 455static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 456{
 457        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 458}
 459
 460static int index_name_pos_also_unmerged(struct index_state *istate,
 461        const char *path, int namelen)
 462{
 463        int pos = index_name_pos(istate, path, namelen);
 464        struct cache_entry *ce;
 465
 466        if (pos >= 0)
 467                return pos;
 468
 469        /* maybe unmerged? */
 470        pos = -1 - pos;
 471        if (pos >= istate->cache_nr ||
 472                        compare_name((ce = istate->cache[pos]), path, namelen))
 473                return -1;
 474
 475        /* order of preference: stage 2, 1, 3 */
 476        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 477                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 478                        !compare_name(ce, path, namelen))
 479                pos++;
 480        return pos;
 481}
 482
 483static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 484{
 485        int len = ce_namelen(ce);
 486        return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 487}
 488
 489/*
 490 * If we add a filename that aliases in the cache, we will use the
 491 * name that we already have - but we don't want to update the same
 492 * alias twice, because that implies that there were actually two
 493 * different files with aliasing names!
 494 *
 495 * So we use the CE_ADDED flag to verify that the alias was an old
 496 * one before we accept it as
 497 */
 498static struct cache_entry *create_alias_ce(struct cache_entry *ce, struct cache_entry *alias)
 499{
 500        int len;
 501        struct cache_entry *new;
 502
 503        if (alias->ce_flags & CE_ADDED)
 504                die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 505
 506        /* Ok, create the new entry using the name of the existing alias */
 507        len = ce_namelen(alias);
 508        new = xcalloc(1, cache_entry_size(len));
 509        memcpy(new->name, alias->name, len);
 510        copy_cache_entry(new, ce);
 511        free(ce);
 512        return new;
 513}
 514
 515static void record_intent_to_add(struct cache_entry *ce)
 516{
 517        unsigned char sha1[20];
 518        if (write_sha1_file("", 0, blob_type, sha1))
 519                die("cannot create an empty blob in the object database");
 520        hashcpy(ce->sha1, sha1);
 521}
 522
 523int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 524{
 525        int size, namelen, was_same;
 526        mode_t st_mode = st->st_mode;
 527        struct cache_entry *ce, *alias;
 528        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY;
 529        int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 530        int pretend = flags & ADD_CACHE_PRETEND;
 531        int intent_only = flags & ADD_CACHE_INTENT;
 532        int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 533                          (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 534
 535        if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 536                return error("%s: can only add regular files, symbolic links or git-directories", path);
 537
 538        namelen = strlen(path);
 539        if (S_ISDIR(st_mode)) {
 540                while (namelen && path[namelen-1] == '/')
 541                        namelen--;
 542        }
 543        size = cache_entry_size(namelen);
 544        ce = xcalloc(1, size);
 545        memcpy(ce->name, path, namelen);
 546        ce->ce_flags = namelen;
 547        if (!intent_only)
 548                fill_stat_cache_info(ce, st);
 549        else
 550                ce->ce_flags |= CE_INTENT_TO_ADD;
 551
 552        if (trust_executable_bit && has_symlinks)
 553                ce->ce_mode = create_ce_mode(st_mode);
 554        else {
 555                /* If there is an existing entry, pick the mode bits and type
 556                 * from it, otherwise assume unexecutable regular file.
 557                 */
 558                struct cache_entry *ent;
 559                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 560
 561                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 562                ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 563        }
 564
 565        alias = index_name_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 566        if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 567                /* Nothing changed, really */
 568                free(ce);
 569                ce_mark_uptodate(alias);
 570                alias->ce_flags |= CE_ADDED;
 571                return 0;
 572        }
 573        if (!intent_only) {
 574                if (index_path(ce->sha1, path, st, 1))
 575                        return error("unable to index file %s", path);
 576        } else
 577                record_intent_to_add(ce);
 578
 579        if (ignore_case && alias && different_name(ce, alias))
 580                ce = create_alias_ce(ce, alias);
 581        ce->ce_flags |= CE_ADDED;
 582
 583        /* It was suspected to be racily clean, but it turns out to be Ok */
 584        was_same = (alias &&
 585                    !ce_stage(alias) &&
 586                    !hashcmp(alias->sha1, ce->sha1) &&
 587                    ce->ce_mode == alias->ce_mode);
 588
 589        if (pretend)
 590                ;
 591        else if (add_index_entry(istate, ce, add_option))
 592                return error("unable to add %s to index",path);
 593        if (verbose && !was_same)
 594                printf("add '%s'\n", path);
 595        return 0;
 596}
 597
 598int add_file_to_index(struct index_state *istate, const char *path, int flags)
 599{
 600        struct stat st;
 601        if (lstat(path, &st))
 602                die("%s: unable to stat (%s)", path, strerror(errno));
 603        return add_to_index(istate, path, &st, flags);
 604}
 605
 606struct cache_entry *make_cache_entry(unsigned int mode,
 607                const unsigned char *sha1, const char *path, int stage,
 608                int refresh)
 609{
 610        int size, len;
 611        struct cache_entry *ce;
 612
 613        if (!verify_path(path)) {
 614                error("Invalid path '%s'", path);
 615                return NULL;
 616        }
 617
 618        len = strlen(path);
 619        size = cache_entry_size(len);
 620        ce = xcalloc(1, size);
 621
 622        hashcpy(ce->sha1, sha1);
 623        memcpy(ce->name, path, len);
 624        ce->ce_flags = create_ce_flags(len, stage);
 625        ce->ce_mode = create_ce_mode(mode);
 626
 627        if (refresh)
 628                return refresh_cache_entry(ce, 0);
 629
 630        return ce;
 631}
 632
 633int ce_same_name(struct cache_entry *a, struct cache_entry *b)
 634{
 635        int len = ce_namelen(a);
 636        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 637}
 638
 639int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 640{
 641        const char *match, *name;
 642        int len;
 643
 644        if (!pathspec)
 645                return 1;
 646
 647        len = ce_namelen(ce);
 648        name = ce->name;
 649        while ((match = *pathspec++) != NULL) {
 650                int matchlen = strlen(match);
 651                if (matchlen > len)
 652                        continue;
 653                if (memcmp(name, match, matchlen))
 654                        continue;
 655                if (matchlen && name[matchlen-1] == '/')
 656                        return 1;
 657                if (name[matchlen] == '/' || !name[matchlen])
 658                        return 1;
 659                if (!matchlen)
 660                        return 1;
 661        }
 662        return 0;
 663}
 664
 665/*
 666 * We fundamentally don't like some paths: we don't want
 667 * dot or dot-dot anywhere, and for obvious reasons don't
 668 * want to recurse into ".git" either.
 669 *
 670 * Also, we don't want double slashes or slashes at the
 671 * end that can make pathnames ambiguous.
 672 */
 673static int verify_dotfile(const char *rest)
 674{
 675        /*
 676         * The first character was '.', but that
 677         * has already been discarded, we now test
 678         * the rest.
 679         */
 680        switch (*rest) {
 681        /* "." is not allowed */
 682        case '\0': case '/':
 683                return 0;
 684
 685        /*
 686         * ".git" followed by  NUL or slash is bad. This
 687         * shares the path end test with the ".." case.
 688         */
 689        case 'g':
 690                if (rest[1] != 'i')
 691                        break;
 692                if (rest[2] != 't')
 693                        break;
 694                rest += 2;
 695        /* fallthrough */
 696        case '.':
 697                if (rest[1] == '\0' || rest[1] == '/')
 698                        return 0;
 699        }
 700        return 1;
 701}
 702
 703int verify_path(const char *path)
 704{
 705        char c;
 706
 707        goto inside;
 708        for (;;) {
 709                if (!c)
 710                        return 1;
 711                if (c == '/') {
 712inside:
 713                        c = *path++;
 714                        switch (c) {
 715                        default:
 716                                continue;
 717                        case '/': case '\0':
 718                                break;
 719                        case '.':
 720                                if (verify_dotfile(path))
 721                                        continue;
 722                        }
 723                        return 0;
 724                }
 725                c = *path++;
 726        }
 727}
 728
 729/*
 730 * Do we have another file that has the beginning components being a
 731 * proper superset of the name we're trying to add?
 732 */
 733static int has_file_name(struct index_state *istate,
 734                         const struct cache_entry *ce, int pos, int ok_to_replace)
 735{
 736        int retval = 0;
 737        int len = ce_namelen(ce);
 738        int stage = ce_stage(ce);
 739        const char *name = ce->name;
 740
 741        while (pos < istate->cache_nr) {
 742                struct cache_entry *p = istate->cache[pos++];
 743
 744                if (len >= ce_namelen(p))
 745                        break;
 746                if (memcmp(name, p->name, len))
 747                        break;
 748                if (ce_stage(p) != stage)
 749                        continue;
 750                if (p->name[len] != '/')
 751                        continue;
 752                if (p->ce_flags & CE_REMOVE)
 753                        continue;
 754                retval = -1;
 755                if (!ok_to_replace)
 756                        break;
 757                remove_index_entry_at(istate, --pos);
 758        }
 759        return retval;
 760}
 761
 762/*
 763 * Do we have another file with a pathname that is a proper
 764 * subset of the name we're trying to add?
 765 */
 766static int has_dir_name(struct index_state *istate,
 767                        const struct cache_entry *ce, int pos, int ok_to_replace)
 768{
 769        int retval = 0;
 770        int stage = ce_stage(ce);
 771        const char *name = ce->name;
 772        const char *slash = name + ce_namelen(ce);
 773
 774        for (;;) {
 775                int len;
 776
 777                for (;;) {
 778                        if (*--slash == '/')
 779                                break;
 780                        if (slash <= ce->name)
 781                                return retval;
 782                }
 783                len = slash - name;
 784
 785                pos = index_name_pos(istate, name, create_ce_flags(len, stage));
 786                if (pos >= 0) {
 787                        /*
 788                         * Found one, but not so fast.  This could
 789                         * be a marker that says "I was here, but
 790                         * I am being removed".  Such an entry is
 791                         * not a part of the resulting tree, and
 792                         * it is Ok to have a directory at the same
 793                         * path.
 794                         */
 795                        if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
 796                                retval = -1;
 797                                if (!ok_to_replace)
 798                                        break;
 799                                remove_index_entry_at(istate, pos);
 800                                continue;
 801                        }
 802                }
 803                else
 804                        pos = -pos-1;
 805
 806                /*
 807                 * Trivial optimization: if we find an entry that
 808                 * already matches the sub-directory, then we know
 809                 * we're ok, and we can exit.
 810                 */
 811                while (pos < istate->cache_nr) {
 812                        struct cache_entry *p = istate->cache[pos];
 813                        if ((ce_namelen(p) <= len) ||
 814                            (p->name[len] != '/') ||
 815                            memcmp(p->name, name, len))
 816                                break; /* not our subdirectory */
 817                        if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
 818                                /*
 819                                 * p is at the same stage as our entry, and
 820                                 * is a subdirectory of what we are looking
 821                                 * at, so we cannot have conflicts at our
 822                                 * level or anything shorter.
 823                                 */
 824                                return retval;
 825                        pos++;
 826                }
 827        }
 828        return retval;
 829}
 830
 831/* We may be in a situation where we already have path/file and path
 832 * is being added, or we already have path and path/file is being
 833 * added.  Either one would result in a nonsense tree that has path
 834 * twice when git-write-tree tries to write it out.  Prevent it.
 835 *
 836 * If ok-to-replace is specified, we remove the conflicting entries
 837 * from the cache so the caller should recompute the insert position.
 838 * When this happens, we return non-zero.
 839 */
 840static int check_file_directory_conflict(struct index_state *istate,
 841                                         const struct cache_entry *ce,
 842                                         int pos, int ok_to_replace)
 843{
 844        int retval;
 845
 846        /*
 847         * When ce is an "I am going away" entry, we allow it to be added
 848         */
 849        if (ce->ce_flags & CE_REMOVE)
 850                return 0;
 851
 852        /*
 853         * We check if the path is a sub-path of a subsequent pathname
 854         * first, since removing those will not change the position
 855         * in the array.
 856         */
 857        retval = has_file_name(istate, ce, pos, ok_to_replace);
 858
 859        /*
 860         * Then check if the path might have a clashing sub-directory
 861         * before it.
 862         */
 863        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 864}
 865
 866static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
 867{
 868        int pos;
 869        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
 870        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
 871        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 872        int new_only = option & ADD_CACHE_NEW_ONLY;
 873
 874        cache_tree_invalidate_path(istate->cache_tree, ce->name);
 875        pos = index_name_pos(istate, ce->name, ce->ce_flags);
 876
 877        /* existing match? Just replace it. */
 878        if (pos >= 0) {
 879                if (!new_only)
 880                        replace_index_entry(istate, pos, ce);
 881                return 0;
 882        }
 883        pos = -pos-1;
 884
 885        /*
 886         * Inserting a merged entry ("stage 0") into the index
 887         * will always replace all non-merged entries..
 888         */
 889        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
 890                while (ce_same_name(istate->cache[pos], ce)) {
 891                        ok_to_add = 1;
 892                        if (!remove_index_entry_at(istate, pos))
 893                                break;
 894                }
 895        }
 896
 897        if (!ok_to_add)
 898                return -1;
 899        if (!verify_path(ce->name))
 900                return error("Invalid path '%s'", ce->name);
 901
 902        if (!skip_df_check &&
 903            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 904                if (!ok_to_replace)
 905                        return error("'%s' appears as both a file and as a directory",
 906                                     ce->name);
 907                pos = index_name_pos(istate, ce->name, ce->ce_flags);
 908                pos = -pos-1;
 909        }
 910        return pos + 1;
 911}
 912
 913int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 914{
 915        int pos;
 916
 917        if (option & ADD_CACHE_JUST_APPEND)
 918                pos = istate->cache_nr;
 919        else {
 920                int ret;
 921                ret = add_index_entry_with_check(istate, ce, option);
 922                if (ret <= 0)
 923                        return ret;
 924                pos = ret - 1;
 925        }
 926
 927        /* Make sure the array is big enough .. */
 928        if (istate->cache_nr == istate->cache_alloc) {
 929                istate->cache_alloc = alloc_nr(istate->cache_alloc);
 930                istate->cache = xrealloc(istate->cache,
 931                                        istate->cache_alloc * sizeof(struct cache_entry *));
 932        }
 933
 934        /* Add it in.. */
 935        istate->cache_nr++;
 936        if (istate->cache_nr > pos + 1)
 937                memmove(istate->cache + pos + 1,
 938                        istate->cache + pos,
 939                        (istate->cache_nr - pos - 1) * sizeof(ce));
 940        set_index_entry(istate, pos, ce);
 941        istate->cache_changed = 1;
 942        return 0;
 943}
 944
 945/*
 946 * "refresh" does not calculate a new sha1 file or bring the
 947 * cache up-to-date for mode/content changes. But what it
 948 * _does_ do is to "re-match" the stat information of a file
 949 * with the cache, so that you can refresh the cache for a
 950 * file that hasn't been changed but where the stat entry is
 951 * out of date.
 952 *
 953 * For example, you'd want to do this after doing a "git-read-tree",
 954 * to link up the stat cache details with the proper files.
 955 */
 956static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 957                                             struct cache_entry *ce,
 958                                             unsigned int options, int *err)
 959{
 960        struct stat st;
 961        struct cache_entry *updated;
 962        int changed, size;
 963        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 964
 965        if (ce_uptodate(ce))
 966                return ce;
 967
 968        /*
 969         * CE_VALID means the user promised us that the change to
 970         * the work tree does not matter and told us not to worry.
 971         */
 972        if (!ignore_valid && (ce->ce_flags & CE_VALID)) {
 973                ce_mark_uptodate(ce);
 974                return ce;
 975        }
 976
 977        if (lstat(ce->name, &st) < 0) {
 978                if (err)
 979                        *err = errno;
 980                return NULL;
 981        }
 982
 983        changed = ie_match_stat(istate, ce, &st, options);
 984        if (!changed) {
 985                /*
 986                 * The path is unchanged.  If we were told to ignore
 987                 * valid bit, then we did the actual stat check and
 988                 * found that the entry is unmodified.  If the entry
 989                 * is not marked VALID, this is the place to mark it
 990                 * valid again, under "assume unchanged" mode.
 991                 */
 992                if (ignore_valid && assume_unchanged &&
 993                    !(ce->ce_flags & CE_VALID))
 994                        ; /* mark this one VALID again */
 995                else {
 996                        /*
 997                         * We do not mark the index itself "modified"
 998                         * because CE_UPTODATE flag is in-core only;
 999                         * we are not going to write this change out.
1000                         */
1001                        ce_mark_uptodate(ce);
1002                        return ce;
1003                }
1004        }
1005
1006        if (ie_modified(istate, ce, &st, options)) {
1007                if (err)
1008                        *err = EINVAL;
1009                return NULL;
1010        }
1011
1012        size = ce_size(ce);
1013        updated = xmalloc(size);
1014        memcpy(updated, ce, size);
1015        fill_stat_cache_info(updated, &st);
1016        /*
1017         * If ignore_valid is not set, we should leave CE_VALID bit
1018         * alone.  Otherwise, paths marked with --no-assume-unchanged
1019         * (i.e. things to be edited) will reacquire CE_VALID bit
1020         * automatically, which is not really what we want.
1021         */
1022        if (!ignore_valid && assume_unchanged &&
1023            !(ce->ce_flags & CE_VALID))
1024                updated->ce_flags &= ~CE_VALID;
1025
1026        return updated;
1027}
1028
1029int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
1030{
1031        int i;
1032        int has_errors = 0;
1033        int really = (flags & REFRESH_REALLY) != 0;
1034        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
1035        int quiet = (flags & REFRESH_QUIET) != 0;
1036        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
1037        int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0;
1038        unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0;
1039        const char *needs_update_message;
1040
1041        needs_update_message = ((flags & REFRESH_SAY_CHANGED)
1042                                ? "locally modified" : "needs update");
1043        for (i = 0; i < istate->cache_nr; i++) {
1044                struct cache_entry *ce, *new;
1045                int cache_errno = 0;
1046
1047                ce = istate->cache[i];
1048                if (ignore_submodules && S_ISGITLINK(ce->ce_mode))
1049                        continue;
1050
1051                if (ce_stage(ce)) {
1052                        while ((i < istate->cache_nr) &&
1053                               ! strcmp(istate->cache[i]->name, ce->name))
1054                                i++;
1055                        i--;
1056                        if (allow_unmerged)
1057                                continue;
1058                        printf("%s: needs merge\n", ce->name);
1059                        has_errors = 1;
1060                        continue;
1061                }
1062
1063                if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
1064                        continue;
1065
1066                new = refresh_cache_ent(istate, ce, options, &cache_errno);
1067                if (new == ce)
1068                        continue;
1069                if (!new) {
1070                        if (not_new && cache_errno == ENOENT)
1071                                continue;
1072                        if (really && cache_errno == EINVAL) {
1073                                /* If we are doing --really-refresh that
1074                                 * means the index is not valid anymore.
1075                                 */
1076                                ce->ce_flags &= ~CE_VALID;
1077                                istate->cache_changed = 1;
1078                        }
1079                        if (quiet)
1080                                continue;
1081                        printf("%s: %s\n", ce->name, needs_update_message);
1082                        has_errors = 1;
1083                        continue;
1084                }
1085
1086                replace_index_entry(istate, i, new);
1087        }
1088        return has_errors;
1089}
1090
1091struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
1092{
1093        return refresh_cache_ent(&the_index, ce, really, NULL);
1094}
1095
1096static int verify_hdr(struct cache_header *hdr, unsigned long size)
1097{
1098        git_SHA_CTX c;
1099        unsigned char sha1[20];
1100
1101        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1102                return error("bad signature");
1103        if (hdr->hdr_version != htonl(2) && hdr->hdr_version != htonl(3))
1104                return error("bad index version");
1105        git_SHA1_Init(&c);
1106        git_SHA1_Update(&c, hdr, size - 20);
1107        git_SHA1_Final(sha1, &c);
1108        if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1109                return error("bad index file sha1 signature");
1110        return 0;
1111}
1112
1113static int read_index_extension(struct index_state *istate,
1114                                const char *ext, void *data, unsigned long sz)
1115{
1116        switch (CACHE_EXT(ext)) {
1117        case CACHE_EXT_TREE:
1118                istate->cache_tree = cache_tree_read(data, sz);
1119                break;
1120        default:
1121                if (*ext < 'A' || 'Z' < *ext)
1122                        return error("index uses %.4s extension, which we do not understand",
1123                                     ext);
1124                fprintf(stderr, "ignoring %.4s extension\n", ext);
1125                break;
1126        }
1127        return 0;
1128}
1129
1130int read_index(struct index_state *istate)
1131{
1132        return read_index_from(istate, get_index_file());
1133}
1134
1135static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
1136{
1137        size_t len;
1138        const char *name;
1139
1140        ce->ce_ctime = ntohl(ondisk->ctime.sec);
1141        ce->ce_mtime = ntohl(ondisk->mtime.sec);
1142        ce->ce_dev   = ntohl(ondisk->dev);
1143        ce->ce_ino   = ntohl(ondisk->ino);
1144        ce->ce_mode  = ntohl(ondisk->mode);
1145        ce->ce_uid   = ntohl(ondisk->uid);
1146        ce->ce_gid   = ntohl(ondisk->gid);
1147        ce->ce_size  = ntohl(ondisk->size);
1148        /* On-disk flags are just 16 bits */
1149        ce->ce_flags = ntohs(ondisk->flags);
1150
1151        hashcpy(ce->sha1, ondisk->sha1);
1152
1153        len = ce->ce_flags & CE_NAMEMASK;
1154
1155        if (ce->ce_flags & CE_EXTENDED) {
1156                struct ondisk_cache_entry_extended *ondisk2;
1157                int extended_flags;
1158                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1159                extended_flags = ntohs(ondisk2->flags2) << 16;
1160                /* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
1161                if (extended_flags & ~CE_EXTENDED_FLAGS)
1162                        die("Unknown index entry format %08x", extended_flags);
1163                ce->ce_flags |= extended_flags;
1164                name = ondisk2->name;
1165        }
1166        else
1167                name = ondisk->name;
1168
1169        if (len == CE_NAMEMASK)
1170                len = strlen(name);
1171        /*
1172         * NEEDSWORK: If the original index is crafted, this copy could
1173         * go unchecked.
1174         */
1175        memcpy(ce->name, name, len + 1);
1176}
1177
1178static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1179{
1180        long per_entry;
1181
1182        per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1183
1184        /*
1185         * Alignment can cause differences. This should be "alignof", but
1186         * since that's a gcc'ism, just use the size of a pointer.
1187         */
1188        per_entry += sizeof(void *);
1189        return ondisk_size + entries*per_entry;
1190}
1191
1192/* remember to discard_cache() before reading a different cache! */
1193int read_index_from(struct index_state *istate, const char *path)
1194{
1195        int fd, i;
1196        struct stat st;
1197        unsigned long src_offset, dst_offset;
1198        struct cache_header *hdr;
1199        void *mmap;
1200        size_t mmap_size;
1201
1202        errno = EBUSY;
1203        if (istate->initialized)
1204                return istate->cache_nr;
1205
1206        errno = ENOENT;
1207        istate->timestamp = 0;
1208        fd = open(path, O_RDONLY);
1209        if (fd < 0) {
1210                if (errno == ENOENT)
1211                        return 0;
1212                die("index file open failed (%s)", strerror(errno));
1213        }
1214
1215        if (fstat(fd, &st))
1216                die("cannot stat the open index (%s)", strerror(errno));
1217
1218        errno = EINVAL;
1219        mmap_size = xsize_t(st.st_size);
1220        if (mmap_size < sizeof(struct cache_header) + 20)
1221                die("index file smaller than expected");
1222
1223        mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
1224        close(fd);
1225        if (mmap == MAP_FAILED)
1226                die("unable to map index file");
1227
1228        hdr = mmap;
1229        if (verify_hdr(hdr, mmap_size) < 0)
1230                goto unmap;
1231
1232        istate->cache_nr = ntohl(hdr->hdr_entries);
1233        istate->cache_alloc = alloc_nr(istate->cache_nr);
1234        istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
1235
1236        /*
1237         * The disk format is actually larger than the in-memory format,
1238         * due to space for nsec etc, so even though the in-memory one
1239         * has room for a few  more flags, we can allocate using the same
1240         * index size
1241         */
1242        istate->alloc = xmalloc(estimate_cache_size(mmap_size, istate->cache_nr));
1243        istate->initialized = 1;
1244
1245        src_offset = sizeof(*hdr);
1246        dst_offset = 0;
1247        for (i = 0; i < istate->cache_nr; i++) {
1248                struct ondisk_cache_entry *disk_ce;
1249                struct cache_entry *ce;
1250
1251                disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1252                ce = (struct cache_entry *)((char *)istate->alloc + dst_offset);
1253                convert_from_disk(disk_ce, ce);
1254                set_index_entry(istate, i, ce);
1255
1256                src_offset += ondisk_ce_size(ce);
1257                dst_offset += ce_size(ce);
1258        }
1259        istate->timestamp = st.st_mtime;
1260        while (src_offset <= mmap_size - 20 - 8) {
1261                /* After an array of active_nr index entries,
1262                 * there can be arbitrary number of extended
1263                 * sections, each of which is prefixed with
1264                 * extension name (4-byte) and section length
1265                 * in 4-byte network byte order.
1266                 */
1267                unsigned long extsize;
1268                memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1269                extsize = ntohl(extsize);
1270                if (read_index_extension(istate,
1271                                         (const char *) mmap + src_offset,
1272                                         (char *) mmap + src_offset + 8,
1273                                         extsize) < 0)
1274                        goto unmap;
1275                src_offset += 8;
1276                src_offset += extsize;
1277        }
1278        munmap(mmap, mmap_size);
1279        return istate->cache_nr;
1280
1281unmap:
1282        munmap(mmap, mmap_size);
1283        errno = EINVAL;
1284        die("index file corrupt");
1285}
1286
1287int is_index_unborn(struct index_state *istate)
1288{
1289        return (!istate->cache_nr && !istate->alloc && !istate->timestamp);
1290}
1291
1292int discard_index(struct index_state *istate)
1293{
1294        istate->cache_nr = 0;
1295        istate->cache_changed = 0;
1296        istate->timestamp = 0;
1297        istate->name_hash_initialized = 0;
1298        free_hash(&istate->name_hash);
1299        cache_tree_free(&(istate->cache_tree));
1300        free(istate->alloc);
1301        istate->alloc = NULL;
1302        istate->initialized = 0;
1303
1304        /* no need to throw away allocated active_cache */
1305        return 0;
1306}
1307
1308int unmerged_index(const struct index_state *istate)
1309{
1310        int i;
1311        for (i = 0; i < istate->cache_nr; i++) {
1312                if (ce_stage(istate->cache[i]))
1313                        return 1;
1314        }
1315        return 0;
1316}
1317
1318#define WRITE_BUFFER_SIZE 8192
1319static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1320static unsigned long write_buffer_len;
1321
1322static int ce_write_flush(git_SHA_CTX *context, int fd)
1323{
1324        unsigned int buffered = write_buffer_len;
1325        if (buffered) {
1326                git_SHA1_Update(context, write_buffer, buffered);
1327                if (write_in_full(fd, write_buffer, buffered) != buffered)
1328                        return -1;
1329                write_buffer_len = 0;
1330        }
1331        return 0;
1332}
1333
1334static int ce_write(git_SHA_CTX *context, int fd, void *data, unsigned int len)
1335{
1336        while (len) {
1337                unsigned int buffered = write_buffer_len;
1338                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1339                if (partial > len)
1340                        partial = len;
1341                memcpy(write_buffer + buffered, data, partial);
1342                buffered += partial;
1343                if (buffered == WRITE_BUFFER_SIZE) {
1344                        write_buffer_len = buffered;
1345                        if (ce_write_flush(context, fd))
1346                                return -1;
1347                        buffered = 0;
1348                }
1349                write_buffer_len = buffered;
1350                len -= partial;
1351                data = (char *) data + partial;
1352        }
1353        return 0;
1354}
1355
1356static int write_index_ext_header(git_SHA_CTX *context, int fd,
1357                                  unsigned int ext, unsigned int sz)
1358{
1359        ext = htonl(ext);
1360        sz = htonl(sz);
1361        return ((ce_write(context, fd, &ext, 4) < 0) ||
1362                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1363}
1364
1365static int ce_flush(git_SHA_CTX *context, int fd)
1366{
1367        unsigned int left = write_buffer_len;
1368
1369        if (left) {
1370                write_buffer_len = 0;
1371                git_SHA1_Update(context, write_buffer, left);
1372        }
1373
1374        /* Flush first if not enough space for SHA1 signature */
1375        if (left + 20 > WRITE_BUFFER_SIZE) {
1376                if (write_in_full(fd, write_buffer, left) != left)
1377                        return -1;
1378                left = 0;
1379        }
1380
1381        /* Append the SHA1 signature at the end */
1382        git_SHA1_Final(write_buffer + left, context);
1383        left += 20;
1384        return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1385}
1386
1387static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1388{
1389        /*
1390         * The only thing we care about in this function is to smudge the
1391         * falsely clean entry due to touch-update-touch race, so we leave
1392         * everything else as they are.  We are called for entries whose
1393         * ce_mtime match the index file mtime.
1394         *
1395         * Note that this actually does not do much for gitlinks, for
1396         * which ce_match_stat_basic() always goes to the actual
1397         * contents.  The caller checks with is_racy_timestamp() which
1398         * always says "no" for gitlinks, so we are not called for them ;-)
1399         */
1400        struct stat st;
1401
1402        if (lstat(ce->name, &st) < 0)
1403                return;
1404        if (ce_match_stat_basic(ce, &st))
1405                return;
1406        if (ce_modified_check_fs(ce, &st)) {
1407                /* This is "racily clean"; smudge it.  Note that this
1408                 * is a tricky code.  At first glance, it may appear
1409                 * that it can break with this sequence:
1410                 *
1411                 * $ echo xyzzy >frotz
1412                 * $ git-update-index --add frotz
1413                 * $ : >frotz
1414                 * $ sleep 3
1415                 * $ echo filfre >nitfol
1416                 * $ git-update-index --add nitfol
1417                 *
1418                 * but it does not.  When the second update-index runs,
1419                 * it notices that the entry "frotz" has the same timestamp
1420                 * as index, and if we were to smudge it by resetting its
1421                 * size to zero here, then the object name recorded
1422                 * in index is the 6-byte file but the cached stat information
1423                 * becomes zero --- which would then match what we would
1424                 * obtain from the filesystem next time we stat("frotz").
1425                 *
1426                 * However, the second update-index, before calling
1427                 * this function, notices that the cached size is 6
1428                 * bytes and what is on the filesystem is an empty
1429                 * file, and never calls us, so the cached size information
1430                 * for "frotz" stays 6 which does not match the filesystem.
1431                 */
1432                ce->ce_size = 0;
1433        }
1434}
1435
1436static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
1437{
1438        int size = ondisk_ce_size(ce);
1439        struct ondisk_cache_entry *ondisk = xcalloc(1, size);
1440        char *name;
1441
1442        ondisk->ctime.sec = htonl(ce->ce_ctime);
1443        ondisk->ctime.nsec = 0;
1444        ondisk->mtime.sec = htonl(ce->ce_mtime);
1445        ondisk->mtime.nsec = 0;
1446        ondisk->dev  = htonl(ce->ce_dev);
1447        ondisk->ino  = htonl(ce->ce_ino);
1448        ondisk->mode = htonl(ce->ce_mode);
1449        ondisk->uid  = htonl(ce->ce_uid);
1450        ondisk->gid  = htonl(ce->ce_gid);
1451        ondisk->size = htonl(ce->ce_size);
1452        hashcpy(ondisk->sha1, ce->sha1);
1453        ondisk->flags = htons(ce->ce_flags);
1454        if (ce->ce_flags & CE_EXTENDED) {
1455                struct ondisk_cache_entry_extended *ondisk2;
1456                ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
1457                ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
1458                name = ondisk2->name;
1459        }
1460        else
1461                name = ondisk->name;
1462        memcpy(name, ce->name, ce_namelen(ce));
1463
1464        return ce_write(c, fd, ondisk, size);
1465}
1466
1467int write_index(const struct index_state *istate, int newfd)
1468{
1469        git_SHA_CTX c;
1470        struct cache_header hdr;
1471        int i, err, removed, extended;
1472        struct cache_entry **cache = istate->cache;
1473        int entries = istate->cache_nr;
1474
1475        for (i = removed = extended = 0; i < entries; i++) {
1476                if (cache[i]->ce_flags & CE_REMOVE)
1477                        removed++;
1478
1479                /* reduce extended entries if possible */
1480                cache[i]->ce_flags &= ~CE_EXTENDED;
1481                if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) {
1482                        extended++;
1483                        cache[i]->ce_flags |= CE_EXTENDED;
1484                }
1485        }
1486
1487        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1488        /* for extended format, increase version so older git won't try to read it */
1489        hdr.hdr_version = htonl(extended ? 3 : 2);
1490        hdr.hdr_entries = htonl(entries - removed);
1491
1492        git_SHA1_Init(&c);
1493        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1494                return -1;
1495
1496        for (i = 0; i < entries; i++) {
1497                struct cache_entry *ce = cache[i];
1498                if (ce->ce_flags & CE_REMOVE)
1499                        continue;
1500                if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
1501                        ce_smudge_racily_clean_entry(ce);
1502                if (ce_write_entry(&c, newfd, ce) < 0)
1503                        return -1;
1504        }
1505
1506        /* Write extension data here */
1507        if (istate->cache_tree) {
1508                struct strbuf sb = STRBUF_INIT;
1509
1510                cache_tree_write(&sb, istate->cache_tree);
1511                err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1512                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1513                strbuf_release(&sb);
1514                if (err)
1515                        return -1;
1516        }
1517        return ce_flush(&c, newfd);
1518}
1519
1520/*
1521 * Read the index file that is potentially unmerged into given
1522 * index_state, dropping any unmerged entries.  Returns true is
1523 * the index is unmerged.  Callers who want to refuse to work
1524 * from an unmerged state can call this and check its return value,
1525 * instead of calling read_cache().
1526 */
1527int read_index_unmerged(struct index_state *istate)
1528{
1529        int i;
1530        int unmerged = 0;
1531
1532        read_index(istate);
1533        for (i = 0; i < istate->cache_nr; i++) {
1534                struct cache_entry *ce = istate->cache[i];
1535                struct cache_entry *new_ce;
1536                int size, len;
1537
1538                if (!ce_stage(ce))
1539                        continue;
1540                unmerged = 1;
1541                len = strlen(ce->name);
1542                size = cache_entry_size(len);
1543                new_ce = xcalloc(1, size);
1544                hashcpy(new_ce->sha1, ce->sha1);
1545                memcpy(new_ce->name, ce->name, len);
1546                new_ce->ce_flags = create_ce_flags(len, 0);
1547                new_ce->ce_mode = ce->ce_mode;
1548                if (add_index_entry(istate, new_ce, 0))
1549                        return error("%s: cannot drop to stage #0",
1550                                     ce->name);
1551                i = index_name_pos(istate, new_ce->name, len);
1552        }
1553        return unmerged;
1554}
1555
1556struct update_callback_data
1557{
1558        int flags;
1559        int add_errors;
1560};
1561
1562static void update_callback(struct diff_queue_struct *q,
1563                            struct diff_options *opt, void *cbdata)
1564{
1565        int i;
1566        struct update_callback_data *data = cbdata;
1567
1568        for (i = 0; i < q->nr; i++) {
1569                struct diff_filepair *p = q->queue[i];
1570                const char *path = p->one->path;
1571                switch (p->status) {
1572                default:
1573                        die("unexpected diff status %c", p->status);
1574                case DIFF_STATUS_UNMERGED:
1575                case DIFF_STATUS_MODIFIED:
1576                case DIFF_STATUS_TYPE_CHANGED:
1577                        if (add_file_to_index(&the_index, path, data->flags)) {
1578                                if (!(data->flags & ADD_CACHE_IGNORE_ERRORS))
1579                                        die("updating files failed");
1580                                data->add_errors++;
1581                        }
1582                        break;
1583                case DIFF_STATUS_DELETED:
1584                        if (data->flags & ADD_CACHE_IGNORE_REMOVAL)
1585                                break;
1586                        if (!(data->flags & ADD_CACHE_PRETEND))
1587                                remove_file_from_index(&the_index, path);
1588                        if (data->flags & (ADD_CACHE_PRETEND|ADD_CACHE_VERBOSE))
1589                                printf("remove '%s'\n", path);
1590                        break;
1591                }
1592        }
1593}
1594
1595int add_files_to_cache(const char *prefix, const char **pathspec, int flags)
1596{
1597        struct update_callback_data data;
1598        struct rev_info rev;
1599        init_revisions(&rev, prefix);
1600        setup_revisions(0, NULL, &rev, NULL);
1601        rev.prune_data = pathspec;
1602        rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
1603        rev.diffopt.format_callback = update_callback;
1604        data.flags = flags;
1605        data.add_errors = 0;
1606        rev.diffopt.format_callback_data = &data;
1607        run_diff_files(&rev, DIFF_RACY_IS_MODIFIED);
1608        return !!data.add_errors;
1609}
1610
1611/*
1612 * Returns 1 if the path is an "other" path with respect to
1613 * the index; that is, the path is not mentioned in the index at all,
1614 * either as a file, a directory with some files in the index,
1615 * or as an unmerged entry.
1616 *
1617 * We helpfully remove a trailing "/" from directories so that
1618 * the output of read_directory can be used as-is.
1619 */
1620int index_name_is_other(const struct index_state *istate, const char *name,
1621                int namelen)
1622{
1623        int pos;
1624        if (namelen && name[namelen - 1] == '/')
1625                namelen--;
1626        pos = index_name_pos(istate, name, namelen);
1627        if (0 <= pos)
1628                return 0;       /* exact match */
1629        pos = -pos - 1;
1630        if (pos < istate->cache_nr) {
1631                struct cache_entry *ce = istate->cache[pos];
1632                if (ce_namelen(ce) == namelen &&
1633                    !memcmp(ce->name, name, namelen))
1634                        return 0; /* Yup, this one exists unmerged */
1635        }
1636        return 1;
1637}