read-cache.con commit Export rerere() and launch_editor(). (d8b7db0)
   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
  12/* Index extensions.
  13 *
  14 * The first letter should be 'A'..'Z' for extensions that are not
  15 * necessary for a correct operation (i.e. optimization data).
  16 * When new extensions are added that _needs_ to be understood in
  17 * order to correctly interpret the index file, pick character that
  18 * is outside the range, to cause the reader to abort.
  19 */
  20
  21#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
  22#define CACHE_EXT_TREE 0x54524545       /* "TREE" */
  23
  24struct index_state the_index;
  25
  26/*
  27 * This only updates the "non-critical" parts of the directory
  28 * cache, ie the parts that aren't tracked by GIT, and only used
  29 * to validate the cache.
  30 */
  31void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  32{
  33        ce->ce_ctime.sec = htonl(st->st_ctime);
  34        ce->ce_mtime.sec = htonl(st->st_mtime);
  35#ifdef USE_NSEC
  36        ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
  37        ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
  38#endif
  39        ce->ce_dev = htonl(st->st_dev);
  40        ce->ce_ino = htonl(st->st_ino);
  41        ce->ce_uid = htonl(st->st_uid);
  42        ce->ce_gid = htonl(st->st_gid);
  43        ce->ce_size = htonl(st->st_size);
  44
  45        if (assume_unchanged)
  46                ce->ce_flags |= htons(CE_VALID);
  47}
  48
  49static int ce_compare_data(struct cache_entry *ce, struct stat *st)
  50{
  51        int match = -1;
  52        int fd = open(ce->name, O_RDONLY);
  53
  54        if (fd >= 0) {
  55                unsigned char sha1[20];
  56                if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
  57                        match = hashcmp(sha1, ce->sha1);
  58                /* index_fd() closed the file descriptor already */
  59        }
  60        return match;
  61}
  62
  63static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
  64{
  65        int match = -1;
  66        char *target;
  67        void *buffer;
  68        unsigned long size;
  69        enum object_type type;
  70        int len;
  71
  72        target = xmalloc(expected_size);
  73        len = readlink(ce->name, target, expected_size);
  74        if (len != expected_size) {
  75                free(target);
  76                return -1;
  77        }
  78        buffer = read_sha1_file(ce->sha1, &type, &size);
  79        if (!buffer) {
  80                free(target);
  81                return -1;
  82        }
  83        if (size == expected_size)
  84                match = memcmp(buffer, target, size);
  85        free(buffer);
  86        free(target);
  87        return match;
  88}
  89
  90static int ce_compare_gitlink(struct cache_entry *ce)
  91{
  92        unsigned char sha1[20];
  93
  94        /*
  95         * We don't actually require that the .git directory
  96         * under GITLINK directory be a valid git directory. It
  97         * might even be missing (in case nobody populated that
  98         * sub-project).
  99         *
 100         * If so, we consider it always to match.
 101         */
 102        if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 103                return 0;
 104        return hashcmp(sha1, ce->sha1);
 105}
 106
 107static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 108{
 109        switch (st->st_mode & S_IFMT) {
 110        case S_IFREG:
 111                if (ce_compare_data(ce, st))
 112                        return DATA_CHANGED;
 113                break;
 114        case S_IFLNK:
 115                if (ce_compare_link(ce, xsize_t(st->st_size)))
 116                        return DATA_CHANGED;
 117                break;
 118        case S_IFDIR:
 119                if (S_ISGITLINK(ntohl(ce->ce_mode)))
 120                        return 0;
 121        default:
 122                return TYPE_CHANGED;
 123        }
 124        return 0;
 125}
 126
 127static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 128{
 129        unsigned int changed = 0;
 130
 131        switch (ntohl(ce->ce_mode) & S_IFMT) {
 132        case S_IFREG:
 133                changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 134                /* We consider only the owner x bit to be relevant for
 135                 * "mode changes"
 136                 */
 137                if (trust_executable_bit &&
 138                    (0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
 139                        changed |= MODE_CHANGED;
 140                break;
 141        case S_IFLNK:
 142                if (!S_ISLNK(st->st_mode) &&
 143                    (has_symlinks || !S_ISREG(st->st_mode)))
 144                        changed |= TYPE_CHANGED;
 145                break;
 146        case S_IFGITLINK:
 147                if (!S_ISDIR(st->st_mode))
 148                        changed |= TYPE_CHANGED;
 149                else if (ce_compare_gitlink(ce))
 150                        changed |= DATA_CHANGED;
 151                return changed;
 152        default:
 153                die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
 154        }
 155        if (ce->ce_mtime.sec != htonl(st->st_mtime))
 156                changed |= MTIME_CHANGED;
 157        if (ce->ce_ctime.sec != htonl(st->st_ctime))
 158                changed |= CTIME_CHANGED;
 159
 160#ifdef USE_NSEC
 161        /*
 162         * nsec seems unreliable - not all filesystems support it, so
 163         * as long as it is in the inode cache you get right nsec
 164         * but after it gets flushed, you get zero nsec.
 165         */
 166        if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
 167                changed |= MTIME_CHANGED;
 168        if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
 169                changed |= CTIME_CHANGED;
 170#endif
 171
 172        if (ce->ce_uid != htonl(st->st_uid) ||
 173            ce->ce_gid != htonl(st->st_gid))
 174                changed |= OWNER_CHANGED;
 175        if (ce->ce_ino != htonl(st->st_ino))
 176                changed |= INODE_CHANGED;
 177
 178#ifdef USE_STDEV
 179        /*
 180         * st_dev breaks on network filesystems where different
 181         * clients will have different views of what "device"
 182         * the filesystem is on
 183         */
 184        if (ce->ce_dev != htonl(st->st_dev))
 185                changed |= INODE_CHANGED;
 186#endif
 187
 188        if (ce->ce_size != htonl(st->st_size))
 189                changed |= DATA_CHANGED;
 190
 191        return changed;
 192}
 193
 194int ie_match_stat(struct index_state *istate,
 195                  struct cache_entry *ce, struct stat *st, int options)
 196{
 197        unsigned int changed;
 198        int ignore_valid = options & 01;
 199        int assume_racy_is_modified = options & 02;
 200
 201        /*
 202         * If it's marked as always valid in the index, it's
 203         * valid whatever the checked-out copy says.
 204         */
 205        if (!ignore_valid && (ce->ce_flags & htons(CE_VALID)))
 206                return 0;
 207
 208        changed = ce_match_stat_basic(ce, st);
 209
 210        /*
 211         * Within 1 second of this sequence:
 212         *      echo xyzzy >file && git-update-index --add file
 213         * running this command:
 214         *      echo frotz >file
 215         * would give a falsely clean cache entry.  The mtime and
 216         * length match the cache, and other stat fields do not change.
 217         *
 218         * We could detect this at update-index time (the cache entry
 219         * being registered/updated records the same time as "now")
 220         * and delay the return from git-update-index, but that would
 221         * effectively mean we can make at most one commit per second,
 222         * which is not acceptable.  Instead, we check cache entries
 223         * whose mtime are the same as the index file timestamp more
 224         * carefully than others.
 225         */
 226        if (!changed &&
 227            istate->timestamp &&
 228            istate->timestamp <= ntohl(ce->ce_mtime.sec)) {
 229                if (assume_racy_is_modified)
 230                        changed |= DATA_CHANGED;
 231                else
 232                        changed |= ce_modified_check_fs(ce, st);
 233        }
 234
 235        return changed;
 236}
 237
 238int ie_modified(struct index_state *istate,
 239                struct cache_entry *ce, struct stat *st, int really)
 240{
 241        int changed, changed_fs;
 242        changed = ie_match_stat(istate, ce, st, really);
 243        if (!changed)
 244                return 0;
 245        /*
 246         * If the mode or type has changed, there's no point in trying
 247         * to refresh the entry - it's not going to match
 248         */
 249        if (changed & (MODE_CHANGED | TYPE_CHANGED))
 250                return changed;
 251
 252        /* Immediately after read-tree or update-index --cacheinfo,
 253         * the length field is zero.  For other cases the ce_size
 254         * should match the SHA1 recorded in the index entry.
 255         */
 256        if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
 257                return changed;
 258
 259        changed_fs = ce_modified_check_fs(ce, st);
 260        if (changed_fs)
 261                return changed | changed_fs;
 262        return 0;
 263}
 264
 265int base_name_compare(const char *name1, int len1, int mode1,
 266                      const char *name2, int len2, int mode2)
 267{
 268        unsigned char c1, c2;
 269        int len = len1 < len2 ? len1 : len2;
 270        int cmp;
 271
 272        cmp = memcmp(name1, name2, len);
 273        if (cmp)
 274                return cmp;
 275        c1 = name1[len];
 276        c2 = name2[len];
 277        if (!c1 && S_ISDIR(mode1))
 278                c1 = '/';
 279        if (!c2 && S_ISDIR(mode2))
 280                c2 = '/';
 281        return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 282}
 283
 284int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 285{
 286        int len1 = flags1 & CE_NAMEMASK;
 287        int len2 = flags2 & CE_NAMEMASK;
 288        int len = len1 < len2 ? len1 : len2;
 289        int cmp;
 290
 291        cmp = memcmp(name1, name2, len);
 292        if (cmp)
 293                return cmp;
 294        if (len1 < len2)
 295                return -1;
 296        if (len1 > len2)
 297                return 1;
 298
 299        /* Compare stages  */
 300        flags1 &= CE_STAGEMASK;
 301        flags2 &= CE_STAGEMASK;
 302
 303        if (flags1 < flags2)
 304                return -1;
 305        if (flags1 > flags2)
 306                return 1;
 307        return 0;
 308}
 309
 310int index_name_pos(struct index_state *istate, const char *name, int namelen)
 311{
 312        int first, last;
 313
 314        first = 0;
 315        last = istate->cache_nr;
 316        while (last > first) {
 317                int next = (last + first) >> 1;
 318                struct cache_entry *ce = istate->cache[next];
 319                int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
 320                if (!cmp)
 321                        return next;
 322                if (cmp < 0) {
 323                        last = next;
 324                        continue;
 325                }
 326                first = next+1;
 327        }
 328        return -first-1;
 329}
 330
 331/* Remove entry, return true if there are more entries to go.. */
 332int remove_index_entry_at(struct index_state *istate, int pos)
 333{
 334        istate->cache_changed = 1;
 335        istate->cache_nr--;
 336        if (pos >= istate->cache_nr)
 337                return 0;
 338        memmove(istate->cache + pos,
 339                istate->cache + pos + 1,
 340                (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 341        return 1;
 342}
 343
 344int remove_file_from_index(struct index_state *istate, const char *path)
 345{
 346        int pos = index_name_pos(istate, path, strlen(path));
 347        if (pos < 0)
 348                pos = -pos-1;
 349        cache_tree_invalidate_path(istate->cache_tree, path);
 350        while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 351                remove_index_entry_at(istate, pos);
 352        return 0;
 353}
 354
 355static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 356{
 357        return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 358}
 359
 360static int index_name_pos_also_unmerged(struct index_state *istate,
 361        const char *path, int namelen)
 362{
 363        int pos = index_name_pos(istate, path, namelen);
 364        struct cache_entry *ce;
 365
 366        if (pos >= 0)
 367                return pos;
 368
 369        /* maybe unmerged? */
 370        pos = -1 - pos;
 371        if (pos >= istate->cache_nr ||
 372                        compare_name((ce = istate->cache[pos]), path, namelen))
 373                return -1;
 374
 375        /* order of preference: stage 2, 1, 3 */
 376        if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 377                        ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 378                        !compare_name(ce, path, namelen))
 379                pos++;
 380        return pos;
 381}
 382
 383int add_file_to_index(struct index_state *istate, const char *path, int verbose)
 384{
 385        int size, namelen, pos;
 386        struct stat st;
 387        struct cache_entry *ce;
 388
 389        if (lstat(path, &st))
 390                die("%s: unable to stat (%s)", path, strerror(errno));
 391
 392        if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
 393                die("%s: can only add regular files, symbolic links or git-directories", path);
 394
 395        namelen = strlen(path);
 396        if (S_ISDIR(st.st_mode)) {
 397                while (namelen && path[namelen-1] == '/')
 398                        namelen--;
 399        }
 400        size = cache_entry_size(namelen);
 401        ce = xcalloc(1, size);
 402        memcpy(ce->name, path, namelen);
 403        ce->ce_flags = htons(namelen);
 404        fill_stat_cache_info(ce, &st);
 405
 406        if (trust_executable_bit && has_symlinks)
 407                ce->ce_mode = create_ce_mode(st.st_mode);
 408        else {
 409                /* If there is an existing entry, pick the mode bits and type
 410                 * from it, otherwise assume unexecutable regular file.
 411                 */
 412                struct cache_entry *ent;
 413                int pos = index_name_pos_also_unmerged(istate, path, namelen);
 414
 415                ent = (0 <= pos) ? istate->cache[pos] : NULL;
 416                ce->ce_mode = ce_mode_from_stat(ent, st.st_mode);
 417        }
 418
 419        pos = index_name_pos(istate, ce->name, namelen);
 420        if (0 <= pos &&
 421            !ce_stage(istate->cache[pos]) &&
 422            !ie_modified(istate, istate->cache[pos], &st, 1)) {
 423                /* Nothing changed, really */
 424                free(ce);
 425                return 0;
 426        }
 427
 428        if (index_path(ce->sha1, path, &st, 1))
 429                die("unable to index file %s", path);
 430        if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
 431                die("unable to add %s to index",path);
 432        if (verbose)
 433                printf("add '%s'\n", path);
 434        return 0;
 435}
 436
 437struct cache_entry *make_cache_entry(unsigned int mode,
 438                const unsigned char *sha1, const char *path, int stage,
 439                int refresh)
 440{
 441        int size, len;
 442        struct cache_entry *ce;
 443
 444        if (!verify_path(path))
 445                return NULL;
 446
 447        len = strlen(path);
 448        size = cache_entry_size(len);
 449        ce = xcalloc(1, size);
 450
 451        hashcpy(ce->sha1, sha1);
 452        memcpy(ce->name, path, len);
 453        ce->ce_flags = create_ce_flags(len, stage);
 454        ce->ce_mode = create_ce_mode(mode);
 455
 456        if (refresh)
 457                return refresh_cache_entry(ce, 0);
 458
 459        return ce;
 460}
 461
 462int ce_same_name(struct cache_entry *a, struct cache_entry *b)
 463{
 464        int len = ce_namelen(a);
 465        return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 466}
 467
 468int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 469{
 470        const char *match, *name;
 471        int len;
 472
 473        if (!pathspec)
 474                return 1;
 475
 476        len = ce_namelen(ce);
 477        name = ce->name;
 478        while ((match = *pathspec++) != NULL) {
 479                int matchlen = strlen(match);
 480                if (matchlen > len)
 481                        continue;
 482                if (memcmp(name, match, matchlen))
 483                        continue;
 484                if (matchlen && name[matchlen-1] == '/')
 485                        return 1;
 486                if (name[matchlen] == '/' || !name[matchlen])
 487                        return 1;
 488                if (!matchlen)
 489                        return 1;
 490        }
 491        return 0;
 492}
 493
 494/*
 495 * We fundamentally don't like some paths: we don't want
 496 * dot or dot-dot anywhere, and for obvious reasons don't
 497 * want to recurse into ".git" either.
 498 *
 499 * Also, we don't want double slashes or slashes at the
 500 * end that can make pathnames ambiguous.
 501 */
 502static int verify_dotfile(const char *rest)
 503{
 504        /*
 505         * The first character was '.', but that
 506         * has already been discarded, we now test
 507         * the rest.
 508         */
 509        switch (*rest) {
 510        /* "." is not allowed */
 511        case '\0': case '/':
 512                return 0;
 513
 514        /*
 515         * ".git" followed by  NUL or slash is bad. This
 516         * shares the path end test with the ".." case.
 517         */
 518        case 'g':
 519                if (rest[1] != 'i')
 520                        break;
 521                if (rest[2] != 't')
 522                        break;
 523                rest += 2;
 524        /* fallthrough */
 525        case '.':
 526                if (rest[1] == '\0' || rest[1] == '/')
 527                        return 0;
 528        }
 529        return 1;
 530}
 531
 532int verify_path(const char *path)
 533{
 534        char c;
 535
 536        goto inside;
 537        for (;;) {
 538                if (!c)
 539                        return 1;
 540                if (c == '/') {
 541inside:
 542                        c = *path++;
 543                        switch (c) {
 544                        default:
 545                                continue;
 546                        case '/': case '\0':
 547                                break;
 548                        case '.':
 549                                if (verify_dotfile(path))
 550                                        continue;
 551                        }
 552                        return 0;
 553                }
 554                c = *path++;
 555        }
 556}
 557
 558/*
 559 * Do we have another file that has the beginning components being a
 560 * proper superset of the name we're trying to add?
 561 */
 562static int has_file_name(struct index_state *istate,
 563                         const struct cache_entry *ce, int pos, int ok_to_replace)
 564{
 565        int retval = 0;
 566        int len = ce_namelen(ce);
 567        int stage = ce_stage(ce);
 568        const char *name = ce->name;
 569
 570        while (pos < istate->cache_nr) {
 571                struct cache_entry *p = istate->cache[pos++];
 572
 573                if (len >= ce_namelen(p))
 574                        break;
 575                if (memcmp(name, p->name, len))
 576                        break;
 577                if (ce_stage(p) != stage)
 578                        continue;
 579                if (p->name[len] != '/')
 580                        continue;
 581                if (!ce_stage(p) && !p->ce_mode)
 582                        continue;
 583                retval = -1;
 584                if (!ok_to_replace)
 585                        break;
 586                remove_index_entry_at(istate, --pos);
 587        }
 588        return retval;
 589}
 590
 591/*
 592 * Do we have another file with a pathname that is a proper
 593 * subset of the name we're trying to add?
 594 */
 595static int has_dir_name(struct index_state *istate,
 596                        const struct cache_entry *ce, int pos, int ok_to_replace)
 597{
 598        int retval = 0;
 599        int stage = ce_stage(ce);
 600        const char *name = ce->name;
 601        const char *slash = name + ce_namelen(ce);
 602
 603        for (;;) {
 604                int len;
 605
 606                for (;;) {
 607                        if (*--slash == '/')
 608                                break;
 609                        if (slash <= ce->name)
 610                                return retval;
 611                }
 612                len = slash - name;
 613
 614                pos = index_name_pos(istate, name, ntohs(create_ce_flags(len, stage)));
 615                if (pos >= 0) {
 616                        /*
 617                         * Found one, but not so fast.  This could
 618                         * be a marker that says "I was here, but
 619                         * I am being removed".  Such an entry is
 620                         * not a part of the resulting tree, and
 621                         * it is Ok to have a directory at the same
 622                         * path.
 623                         */
 624                        if (stage || istate->cache[pos]->ce_mode) {
 625                                retval = -1;
 626                                if (!ok_to_replace)
 627                                        break;
 628                                remove_index_entry_at(istate, pos);
 629                                continue;
 630                        }
 631                }
 632                else
 633                        pos = -pos-1;
 634
 635                /*
 636                 * Trivial optimization: if we find an entry that
 637                 * already matches the sub-directory, then we know
 638                 * we're ok, and we can exit.
 639                 */
 640                while (pos < istate->cache_nr) {
 641                        struct cache_entry *p = istate->cache[pos];
 642                        if ((ce_namelen(p) <= len) ||
 643                            (p->name[len] != '/') ||
 644                            memcmp(p->name, name, len))
 645                                break; /* not our subdirectory */
 646                        if (ce_stage(p) == stage && (stage || p->ce_mode))
 647                                /* p is at the same stage as our entry, and
 648                                 * is a subdirectory of what we are looking
 649                                 * at, so we cannot have conflicts at our
 650                                 * level or anything shorter.
 651                                 */
 652                                return retval;
 653                        pos++;
 654                }
 655        }
 656        return retval;
 657}
 658
 659/* We may be in a situation where we already have path/file and path
 660 * is being added, or we already have path and path/file is being
 661 * added.  Either one would result in a nonsense tree that has path
 662 * twice when git-write-tree tries to write it out.  Prevent it.
 663 *
 664 * If ok-to-replace is specified, we remove the conflicting entries
 665 * from the cache so the caller should recompute the insert position.
 666 * When this happens, we return non-zero.
 667 */
 668static int check_file_directory_conflict(struct index_state *istate,
 669                                         const struct cache_entry *ce,
 670                                         int pos, int ok_to_replace)
 671{
 672        int retval;
 673
 674        /*
 675         * When ce is an "I am going away" entry, we allow it to be added
 676         */
 677        if (!ce_stage(ce) && !ce->ce_mode)
 678                return 0;
 679
 680        /*
 681         * We check if the path is a sub-path of a subsequent pathname
 682         * first, since removing those will not change the position
 683         * in the array.
 684         */
 685        retval = has_file_name(istate, ce, pos, ok_to_replace);
 686
 687        /*
 688         * Then check if the path might have a clashing sub-directory
 689         * before it.
 690         */
 691        return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 692}
 693
 694static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
 695{
 696        int pos;
 697        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
 698        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
 699        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 700
 701        cache_tree_invalidate_path(istate->cache_tree, ce->name);
 702        pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
 703
 704        /* existing match? Just replace it. */
 705        if (pos >= 0) {
 706                istate->cache_changed = 1;
 707                istate->cache[pos] = ce;
 708                return 0;
 709        }
 710        pos = -pos-1;
 711
 712        /*
 713         * Inserting a merged entry ("stage 0") into the index
 714         * will always replace all non-merged entries..
 715         */
 716        if (pos < istate->cache_nr && ce_stage(ce) == 0) {
 717                while (ce_same_name(istate->cache[pos], ce)) {
 718                        ok_to_add = 1;
 719                        if (!remove_index_entry_at(istate, pos))
 720                                break;
 721                }
 722        }
 723
 724        if (!ok_to_add)
 725                return -1;
 726        if (!verify_path(ce->name))
 727                return -1;
 728
 729        if (!skip_df_check &&
 730            check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 731                if (!ok_to_replace)
 732                        return error("'%s' appears as both a file and as a directory",
 733                                     ce->name);
 734                pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
 735                pos = -pos-1;
 736        }
 737        return pos + 1;
 738}
 739
 740int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 741{
 742        int pos;
 743
 744        if (option & ADD_CACHE_JUST_APPEND)
 745                pos = istate->cache_nr;
 746        else {
 747                int ret;
 748                ret = add_index_entry_with_check(istate, ce, option);
 749                if (ret <= 0)
 750                        return ret;
 751                pos = ret - 1;
 752        }
 753
 754        /* Make sure the array is big enough .. */
 755        if (istate->cache_nr == istate->cache_alloc) {
 756                istate->cache_alloc = alloc_nr(istate->cache_alloc);
 757                istate->cache = xrealloc(istate->cache,
 758                                        istate->cache_alloc * sizeof(struct cache_entry *));
 759        }
 760
 761        /* Add it in.. */
 762        istate->cache_nr++;
 763        if (istate->cache_nr > pos + 1)
 764                memmove(istate->cache + pos + 1,
 765                        istate->cache + pos,
 766                        (istate->cache_nr - pos - 1) * sizeof(ce));
 767        istate->cache[pos] = ce;
 768        istate->cache_changed = 1;
 769        return 0;
 770}
 771
 772/*
 773 * "refresh" does not calculate a new sha1 file or bring the
 774 * cache up-to-date for mode/content changes. But what it
 775 * _does_ do is to "re-match" the stat information of a file
 776 * with the cache, so that you can refresh the cache for a
 777 * file that hasn't been changed but where the stat entry is
 778 * out of date.
 779 *
 780 * For example, you'd want to do this after doing a "git-read-tree",
 781 * to link up the stat cache details with the proper files.
 782 */
 783static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 784                                             struct cache_entry *ce, int really, int *err)
 785{
 786        struct stat st;
 787        struct cache_entry *updated;
 788        int changed, size;
 789
 790        if (lstat(ce->name, &st) < 0) {
 791                if (err)
 792                        *err = errno;
 793                return NULL;
 794        }
 795
 796        changed = ie_match_stat(istate, ce, &st, really);
 797        if (!changed) {
 798                if (really && assume_unchanged &&
 799                    !(ce->ce_flags & htons(CE_VALID)))
 800                        ; /* mark this one VALID again */
 801                else
 802                        return ce;
 803        }
 804
 805        if (ie_modified(istate, ce, &st, really)) {
 806                if (err)
 807                        *err = EINVAL;
 808                return NULL;
 809        }
 810
 811        size = ce_size(ce);
 812        updated = xmalloc(size);
 813        memcpy(updated, ce, size);
 814        fill_stat_cache_info(updated, &st);
 815
 816        /* In this case, if really is not set, we should leave
 817         * CE_VALID bit alone.  Otherwise, paths marked with
 818         * --no-assume-unchanged (i.e. things to be edited) will
 819         * reacquire CE_VALID bit automatically, which is not
 820         * really what we want.
 821         */
 822        if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID)))
 823                updated->ce_flags &= ~htons(CE_VALID);
 824
 825        return updated;
 826}
 827
 828int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
 829{
 830        int i;
 831        int has_errors = 0;
 832        int really = (flags & REFRESH_REALLY) != 0;
 833        int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
 834        int quiet = (flags & REFRESH_QUIET) != 0;
 835        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
 836
 837        for (i = 0; i < istate->cache_nr; i++) {
 838                struct cache_entry *ce, *new;
 839                int cache_errno = 0;
 840
 841                ce = istate->cache[i];
 842                if (ce_stage(ce)) {
 843                        while ((i < istate->cache_nr) &&
 844                               ! strcmp(istate->cache[i]->name, ce->name))
 845                                i++;
 846                        i--;
 847                        if (allow_unmerged)
 848                                continue;
 849                        printf("%s: needs merge\n", ce->name);
 850                        has_errors = 1;
 851                        continue;
 852                }
 853
 854                if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
 855                        continue;
 856
 857                new = refresh_cache_ent(istate, ce, really, &cache_errno);
 858                if (new == ce)
 859                        continue;
 860                if (!new) {
 861                        if (not_new && cache_errno == ENOENT)
 862                                continue;
 863                        if (really && cache_errno == EINVAL) {
 864                                /* If we are doing --really-refresh that
 865                                 * means the index is not valid anymore.
 866                                 */
 867                                ce->ce_flags &= ~htons(CE_VALID);
 868                                istate->cache_changed = 1;
 869                        }
 870                        if (quiet)
 871                                continue;
 872                        printf("%s: needs update\n", ce->name);
 873                        has_errors = 1;
 874                        continue;
 875                }
 876                istate->cache_changed = 1;
 877                /* You can NOT just free istate->cache[i] here, since it
 878                 * might not be necessarily malloc()ed but can also come
 879                 * from mmap(). */
 880                istate->cache[i] = new;
 881        }
 882        return has_errors;
 883}
 884
 885struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
 886{
 887        return refresh_cache_ent(&the_index, ce, really, NULL);
 888}
 889
 890static int verify_hdr(struct cache_header *hdr, unsigned long size)
 891{
 892        SHA_CTX c;
 893        unsigned char sha1[20];
 894
 895        if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
 896                return error("bad signature");
 897        if (hdr->hdr_version != htonl(2))
 898                return error("bad index version");
 899        SHA1_Init(&c);
 900        SHA1_Update(&c, hdr, size - 20);
 901        SHA1_Final(sha1, &c);
 902        if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
 903                return error("bad index file sha1 signature");
 904        return 0;
 905}
 906
 907static int read_index_extension(struct index_state *istate,
 908                                const char *ext, void *data, unsigned long sz)
 909{
 910        switch (CACHE_EXT(ext)) {
 911        case CACHE_EXT_TREE:
 912                istate->cache_tree = cache_tree_read(data, sz);
 913                break;
 914        default:
 915                if (*ext < 'A' || 'Z' < *ext)
 916                        return error("index uses %.4s extension, which we do not understand",
 917                                     ext);
 918                fprintf(stderr, "ignoring %.4s extension\n", ext);
 919                break;
 920        }
 921        return 0;
 922}
 923
 924int read_index(struct index_state *istate)
 925{
 926        return read_index_from(istate, get_index_file());
 927}
 928
 929/* remember to discard_cache() before reading a different cache! */
 930int read_index_from(struct index_state *istate, const char *path)
 931{
 932        int fd, i;
 933        struct stat st;
 934        unsigned long offset;
 935        struct cache_header *hdr;
 936
 937        errno = EBUSY;
 938        if (istate->mmap)
 939                return istate->cache_nr;
 940
 941        errno = ENOENT;
 942        istate->timestamp = 0;
 943        fd = open(path, O_RDONLY);
 944        if (fd < 0) {
 945                if (errno == ENOENT)
 946                        return 0;
 947                die("index file open failed (%s)", strerror(errno));
 948        }
 949
 950        if (fstat(fd, &st))
 951                die("cannot stat the open index (%s)", strerror(errno));
 952
 953        errno = EINVAL;
 954        istate->mmap_size = xsize_t(st.st_size);
 955        if (istate->mmap_size < sizeof(struct cache_header) + 20)
 956                die("index file smaller than expected");
 957
 958        istate->mmap = xmmap(NULL, istate->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
 959        close(fd);
 960
 961        hdr = istate->mmap;
 962        if (verify_hdr(hdr, istate->mmap_size) < 0)
 963                goto unmap;
 964
 965        istate->cache_nr = ntohl(hdr->hdr_entries);
 966        istate->cache_alloc = alloc_nr(istate->cache_nr);
 967        istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
 968
 969        offset = sizeof(*hdr);
 970        for (i = 0; i < istate->cache_nr; i++) {
 971                struct cache_entry *ce;
 972
 973                ce = (struct cache_entry *)((char *)(istate->mmap) + offset);
 974                offset = offset + ce_size(ce);
 975                istate->cache[i] = ce;
 976        }
 977        istate->timestamp = st.st_mtime;
 978        while (offset <= istate->mmap_size - 20 - 8) {
 979                /* After an array of active_nr index entries,
 980                 * there can be arbitrary number of extended
 981                 * sections, each of which is prefixed with
 982                 * extension name (4-byte) and section length
 983                 * in 4-byte network byte order.
 984                 */
 985                unsigned long extsize;
 986                memcpy(&extsize, (char *)(istate->mmap) + offset + 4, 4);
 987                extsize = ntohl(extsize);
 988                if (read_index_extension(istate,
 989                                         ((const char *) (istate->mmap)) + offset,
 990                                         (char *) (istate->mmap) + offset + 8,
 991                                         extsize) < 0)
 992                        goto unmap;
 993                offset += 8;
 994                offset += extsize;
 995        }
 996        return istate->cache_nr;
 997
 998unmap:
 999        munmap(istate->mmap, istate->mmap_size);
1000        errno = EINVAL;
1001        die("index file corrupt");
1002}
1003
1004int discard_index(struct index_state *istate)
1005{
1006        int ret;
1007
1008        istate->cache_nr = 0;
1009        istate->cache_changed = 0;
1010        istate->timestamp = 0;
1011        cache_tree_free(&(istate->cache_tree));
1012        if (istate->mmap == NULL)
1013                return 0;
1014        ret = munmap(istate->mmap, istate->mmap_size);
1015        istate->mmap = NULL;
1016        istate->mmap_size = 0;
1017
1018        /* no need to throw away allocated active_cache */
1019        return ret;
1020}
1021
1022#define WRITE_BUFFER_SIZE 8192
1023static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1024static unsigned long write_buffer_len;
1025
1026static int ce_write_flush(SHA_CTX *context, int fd)
1027{
1028        unsigned int buffered = write_buffer_len;
1029        if (buffered) {
1030                SHA1_Update(context, write_buffer, buffered);
1031                if (write_in_full(fd, write_buffer, buffered) != buffered)
1032                        return -1;
1033                write_buffer_len = 0;
1034        }
1035        return 0;
1036}
1037
1038static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
1039{
1040        while (len) {
1041                unsigned int buffered = write_buffer_len;
1042                unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1043                if (partial > len)
1044                        partial = len;
1045                memcpy(write_buffer + buffered, data, partial);
1046                buffered += partial;
1047                if (buffered == WRITE_BUFFER_SIZE) {
1048                        write_buffer_len = buffered;
1049                        if (ce_write_flush(context, fd))
1050                                return -1;
1051                        buffered = 0;
1052                }
1053                write_buffer_len = buffered;
1054                len -= partial;
1055                data = (char *) data + partial;
1056        }
1057        return 0;
1058}
1059
1060static int write_index_ext_header(SHA_CTX *context, int fd,
1061                                  unsigned int ext, unsigned int sz)
1062{
1063        ext = htonl(ext);
1064        sz = htonl(sz);
1065        return ((ce_write(context, fd, &ext, 4) < 0) ||
1066                (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1067}
1068
1069static int ce_flush(SHA_CTX *context, int fd)
1070{
1071        unsigned int left = write_buffer_len;
1072
1073        if (left) {
1074                write_buffer_len = 0;
1075                SHA1_Update(context, write_buffer, left);
1076        }
1077
1078        /* Flush first if not enough space for SHA1 signature */
1079        if (left + 20 > WRITE_BUFFER_SIZE) {
1080                if (write_in_full(fd, write_buffer, left) != left)
1081                        return -1;
1082                left = 0;
1083        }
1084
1085        /* Append the SHA1 signature at the end */
1086        SHA1_Final(write_buffer + left, context);
1087        left += 20;
1088        return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1089}
1090
1091static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1092{
1093        /*
1094         * The only thing we care about in this function is to smudge the
1095         * falsely clean entry due to touch-update-touch race, so we leave
1096         * everything else as they are.  We are called for entries whose
1097         * ce_mtime match the index file mtime.
1098         */
1099        struct stat st;
1100
1101        if (lstat(ce->name, &st) < 0)
1102                return;
1103        if (ce_match_stat_basic(ce, &st))
1104                return;
1105        if (ce_modified_check_fs(ce, &st)) {
1106                /* This is "racily clean"; smudge it.  Note that this
1107                 * is a tricky code.  At first glance, it may appear
1108                 * that it can break with this sequence:
1109                 *
1110                 * $ echo xyzzy >frotz
1111                 * $ git-update-index --add frotz
1112                 * $ : >frotz
1113                 * $ sleep 3
1114                 * $ echo filfre >nitfol
1115                 * $ git-update-index --add nitfol
1116                 *
1117                 * but it does not.  When the second update-index runs,
1118                 * it notices that the entry "frotz" has the same timestamp
1119                 * as index, and if we were to smudge it by resetting its
1120                 * size to zero here, then the object name recorded
1121                 * in index is the 6-byte file but the cached stat information
1122                 * becomes zero --- which would then match what we would
1123                 * obtain from the filesystem next time we stat("frotz").
1124                 *
1125                 * However, the second update-index, before calling
1126                 * this function, notices that the cached size is 6
1127                 * bytes and what is on the filesystem is an empty
1128                 * file, and never calls us, so the cached size information
1129                 * for "frotz" stays 6 which does not match the filesystem.
1130                 */
1131                ce->ce_size = htonl(0);
1132        }
1133}
1134
1135int write_index(struct index_state *istate, int newfd)
1136{
1137        SHA_CTX c;
1138        struct cache_header hdr;
1139        int i, err, removed;
1140        struct cache_entry **cache = istate->cache;
1141        int entries = istate->cache_nr;
1142
1143        for (i = removed = 0; i < entries; i++)
1144                if (!cache[i]->ce_mode)
1145                        removed++;
1146
1147        hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1148        hdr.hdr_version = htonl(2);
1149        hdr.hdr_entries = htonl(entries - removed);
1150
1151        SHA1_Init(&c);
1152        if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1153                return -1;
1154
1155        for (i = 0; i < entries; i++) {
1156                struct cache_entry *ce = cache[i];
1157                if (!ce->ce_mode)
1158                        continue;
1159                if (istate->timestamp &&
1160                    istate->timestamp <= ntohl(ce->ce_mtime.sec))
1161                        ce_smudge_racily_clean_entry(ce);
1162                if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
1163                        return -1;
1164        }
1165
1166        /* Write extension data here */
1167        if (istate->cache_tree) {
1168                struct strbuf sb;
1169
1170                strbuf_init(&sb, 0);
1171                cache_tree_write(&sb, istate->cache_tree);
1172                err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1173                        || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1174                strbuf_release(&sb);
1175                if (err)
1176                        return -1;
1177        }
1178        return ce_flush(&c, newfd);
1179}