read-cache.c

   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
  24 struct index_state the_index;
  25
  26 static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  27 {
  28         istate->cache[nr] = ce;
  29         add_name_hash(istate, ce);
  30 }
  31
  32 static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
  33 {
  34         struct cache_entry *old = istate->cache[nr];
  35
  36         remove_name_hash(old);
  37         set_index_entry(istate, nr, ce);
  38         istate->cache_changed = 1;
  39 }
  40
  41 /*
  42  * This only updates the "non-critical" parts of the directory
  43  * cache, ie the parts that aren't tracked by GIT, and only used
  44  * to validate the cache.
  45  */
  46 void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
  47 {
  48         ce->ce_ctime = st->st_ctime;
  49         ce->ce_mtime = st->st_mtime;
  50         ce->ce_dev = st->st_dev;
  51         ce->ce_ino = st->st_ino;
  52         ce->ce_uid = st->st_uid;
  53         ce->ce_gid = st->st_gid;
  54         ce->ce_size = st->st_size;
  55
  56         if (assume_unchanged)
  57                 ce->ce_flags |= CE_VALID;
  58
  59         if (S_ISREG(st->st_mode))
  60                 ce_mark_uptodate(ce);
  61 }
  62
  63 static int ce_compare_data(struct cache_entry *ce, struct stat *st)
  64 {
  65         int match = -1;
  66         int fd = open(ce->name, O_RDONLY);
  67
  68         if (fd >= 0) {
  69                 unsigned char sha1[20];
  70                 if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
  71                         match = hashcmp(sha1, ce->sha1);
  72                 /* index_fd() closed the file descriptor already */
  73         }
  74         return match;
  75 }
  76
  77 static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
  78 {
  79         int match = -1;
  80         char *target;
  81         void *buffer;
  82         unsigned long size;
  83         enum object_type type;
  84         int len;
  85
  86         target = xmalloc(expected_size);
  87         len = readlink(ce->name, target, expected_size);
  88         if (len != expected_size) {
  89                 free(target);
  90                 return -1;
  91         }
  92         buffer = read_sha1_file(ce->sha1, &type, &size);
  93         if (!buffer) {
  94                 free(target);
  95                 return -1;
  96         }
  97         if (size == expected_size)
  98                 match = memcmp(buffer, target, size);
  99         free(buffer);
 100         free(target);
 101         return match;
 102 }
 103
 104 static int ce_compare_gitlink(struct cache_entry *ce)
 105 {
 106         unsigned char sha1[20];
 107
 108         /*
 109          * We don't actually require that the .git directory
 110          * under GITLINK directory be a valid git directory. It
 111          * might even be missing (in case nobody populated that
 112          * sub-project).
 113          *
 114          * If so, we consider it always to match.
 115          */
 116         if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
 117                 return 0;
 118         return hashcmp(sha1, ce->sha1);
 119 }
 120
 121 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 122 {
 123         switch (st->st_mode & S_IFMT) {
 124         case S_IFREG:
 125                 if (ce_compare_data(ce, st))
 126                         return DATA_CHANGED;
 127                 break;
 128         case S_IFLNK:
 129                 if (ce_compare_link(ce, xsize_t(st->st_size)))
 130                         return DATA_CHANGED;
 131                 break;
 132         case S_IFDIR:
 133                 if (S_ISGITLINK(ce->ce_mode))
 134                         return 0;
 135         default:
 136                 return TYPE_CHANGED;
 137         }
 138         return 0;
 139 }
 140
 141 static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
 142 {
 143         unsigned int changed = 0;
 144
 145         if (ce->ce_flags & CE_REMOVE)
 146                 return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
 147
 148         switch (ce->ce_mode & S_IFMT) {
 149         case S_IFREG:
 150                 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
 151                 /* We consider only the owner x bit to be relevant for
 152                  * "mode changes"
 153                  */
 154                 if (trust_executable_bit &&
 155                     (0100 & (ce->ce_mode ^ st->st_mode)))
 156                         changed |= MODE_CHANGED;
 157                 break;
 158         case S_IFLNK:
 159                 if (!S_ISLNK(st->st_mode) &&
 160                     (has_symlinks || !S_ISREG(st->st_mode)))
 161                         changed |= TYPE_CHANGED;
 162                 break;
 163         case S_IFGITLINK:
 164                 if (!S_ISDIR(st->st_mode))
 165                         changed |= TYPE_CHANGED;
 166                 else if (ce_compare_gitlink(ce))
 167                         changed |= DATA_CHANGED;
 168                 return changed;
 169         default:
 170                 die("internal error: ce_mode is %o", ce->ce_mode);
 171         }
 172         if (ce->ce_mtime != (unsigned int) st->st_mtime)
 173                 changed |= MTIME_CHANGED;
 174         if (ce->ce_ctime != (unsigned int) st->st_ctime)
 175                 changed |= CTIME_CHANGED;
 176
 177         if (ce->ce_uid != (unsigned int) st->st_uid ||
 178             ce->ce_gid != (unsigned int) st->st_gid)
 179                 changed |= OWNER_CHANGED;
 180         if (ce->ce_ino != (unsigned int) st->st_ino)
 181                 changed |= INODE_CHANGED;
 182
 183 #ifdef USE_STDEV
 184         /*
 185          * st_dev breaks on network filesystems where different
 186          * clients will have different views of what "device"
 187          * the filesystem is on
 188          */
 189         if (ce->ce_dev != (unsigned int) st->st_dev)
 190                 changed |= INODE_CHANGED;
 191 #endif
 192
 193         if (ce->ce_size != (unsigned int) st->st_size)
 194                 changed |= DATA_CHANGED;
 195
 196         return changed;
 197 }
 198
 199 static int is_racy_timestamp(const struct index_state *istate, struct cache_entry *ce)
 200 {
 201         return (!S_ISGITLINK(ce->ce_mode) &&
 202                 istate->timestamp &&
 203                 ((unsigned int)istate->timestamp) <= ce->ce_mtime);
 204 }
 205
 206 int ie_match_stat(const struct index_state *istate,
 207                   struct cache_entry *ce, struct stat *st,
 208                   unsigned int options)
 209 {
 210         unsigned int changed;
 211         int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 212         int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
 213
 214         /*
 215          * If it's marked as always valid in the index, it's
 216          * valid whatever the checked-out copy says.
 217          */
 218         if (!ignore_valid && (ce->ce_flags & CE_VALID))
 219                 return 0;
 220
 221         changed = ce_match_stat_basic(ce, st);
 222
 223         /*
 224          * Within 1 second of this sequence:
 225          *      echo xyzzy >file && git-update-index --add file
 226          * running this command:
 227          *      echo frotz >file
 228          * would give a falsely clean cache entry.  The mtime and
 229          * length match the cache, and other stat fields do not change.
 230          *
 231          * We could detect this at update-index time (the cache entry
 232          * being registered/updated records the same time as "now")
 233          * and delay the return from git-update-index, but that would
 234          * effectively mean we can make at most one commit per second,
 235          * which is not acceptable.  Instead, we check cache entries
 236          * whose mtime are the same as the index file timestamp more
 237          * carefully than others.
 238          */
 239         if (!changed && is_racy_timestamp(istate, ce)) {
 240                 if (assume_racy_is_modified)
 241                         changed |= DATA_CHANGED;
 242                 else
 243                         changed |= ce_modified_check_fs(ce, st);
 244         }
 245
 246         return changed;
 247 }
 248
 249 int ie_modified(const struct index_state *istate,
 250                 struct cache_entry *ce, struct stat *st, unsigned int options)
 251 {
 252         int changed, changed_fs;
 253
 254         changed = ie_match_stat(istate, ce, st, options);
 255         if (!changed)
 256                 return 0;
 257         /*
 258          * If the mode or type has changed, there's no point in trying
 259          * to refresh the entry - it's not going to match
 260          */
 261         if (changed & (MODE_CHANGED | TYPE_CHANGED))
 262                 return changed;
 263
 264         /* Immediately after read-tree or update-index --cacheinfo,
 265          * the length field is zero.  For other cases the ce_size
 266          * should match the SHA1 recorded in the index entry.
 267          */
 268         if ((changed & DATA_CHANGED) && ce->ce_size != 0)
 269                 return changed;
 270
 271         changed_fs = ce_modified_check_fs(ce, st);
 272         if (changed_fs)
 273                 return changed | changed_fs;
 274         return 0;
 275 }
 276
 277 int base_name_compare(const char *name1, int len1, int mode1,
 278                       const char *name2, int len2, int mode2)
 279 {
 280         unsigned char c1, c2;
 281         int len = len1 < len2 ? len1 : len2;
 282         int cmp;
 283
 284         cmp = memcmp(name1, name2, len);
 285         if (cmp)
 286                 return cmp;
 287         c1 = name1[len];
 288         c2 = name2[len];
 289         if (!c1 && S_ISDIR(mode1))
 290                 c1 = '/';
 291         if (!c2 && S_ISDIR(mode2))
 292                 c2 = '/';
 293         return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
 294 }
 295
 296 /*
 297  * df_name_compare() is identical to base_name_compare(), except it
 298  * compares conflicting directory/file entries as equal. Note that
 299  * while a directory name compares as equal to a regular file, they
 300  * then individually compare _differently_ to a filename that has
 301  * a dot after the basename (because '\0' < '.' < '/').
 302  *
 303  * This is used by routines that want to traverse the git namespace
 304  * but then handle conflicting entries together when possible.
 305  */
 306 int df_name_compare(const char *name1, int len1, int mode1,
 307                     const char *name2, int len2, int mode2)
 308 {
 309         int len = len1 < len2 ? len1 : len2, cmp;
 310         unsigned char c1, c2;
 311
 312         cmp = memcmp(name1, name2, len);
 313         if (cmp)
 314                 return cmp;
 315         /* Directories and files compare equal (same length, same name) */
 316         if (len1 == len2)
 317                 return 0;
 318         c1 = name1[len];
 319         if (!c1 && S_ISDIR(mode1))
 320                 c1 = '/';
 321         c2 = name2[len];
 322         if (!c2 && S_ISDIR(mode2))
 323                 c2 = '/';
 324         if (c1 == '/' && !c2)
 325                 return 0;
 326         if (c2 == '/' && !c1)
 327                 return 0;
 328         return c1 - c2;
 329 }
 330
 331 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
 332 {
 333         int len1 = flags1 & CE_NAMEMASK;
 334         int len2 = flags2 & CE_NAMEMASK;
 335         int len = len1 < len2 ? len1 : len2;
 336         int cmp;
 337
 338         cmp = memcmp(name1, name2, len);
 339         if (cmp)
 340                 return cmp;
 341         if (len1 < len2)
 342                 return -1;
 343         if (len1 > len2)
 344                 return 1;
 345
 346         /* Compare stages  */
 347         flags1 &= CE_STAGEMASK;
 348         flags2 &= CE_STAGEMASK;
 349
 350         if (flags1 < flags2)
 351                 return -1;
 352         if (flags1 > flags2)
 353                 return 1;
 354         return 0;
 355 }
 356
 357 int index_name_pos(const struct index_state *istate, const char *name, int namelen)
 358 {
 359         int first, last;
 360
 361         first = 0;
 362         last = istate->cache_nr;
 363         while (last > first) {
 364                 int next = (last + first) >> 1;
 365                 struct cache_entry *ce = istate->cache[next];
 366                 int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
 367                 if (!cmp)
 368                         return next;
 369                 if (cmp < 0) {
 370                         last = next;
 371                         continue;
 372                 }
 373                 first = next+1;
 374         }
 375         return -first-1;
 376 }
 377
 378 /* Remove entry, return true if there are more entries to go.. */
 379 int remove_index_entry_at(struct index_state *istate, int pos)
 380 {
 381         struct cache_entry *ce = istate->cache[pos];
 382
 383         remove_name_hash(ce);
 384         istate->cache_changed = 1;
 385         istate->cache_nr--;
 386         if (pos >= istate->cache_nr)
 387                 return 0;
 388         memmove(istate->cache + pos,
 389                 istate->cache + pos + 1,
 390                 (istate->cache_nr - pos) * sizeof(struct cache_entry *));
 391         return 1;
 392 }
 393
 394 int remove_file_from_index(struct index_state *istate, const char *path)
 395 {
 396         int pos = index_name_pos(istate, path, strlen(path));
 397         if (pos < 0)
 398                 pos = -pos-1;
 399         cache_tree_invalidate_path(istate->cache_tree, path);
 400         while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
 401                 remove_index_entry_at(istate, pos);
 402         return 0;
 403 }
 404
 405 static int compare_name(struct cache_entry *ce, const char *path, int namelen)
 406 {
 407         return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
 408 }
 409
 410 static int index_name_pos_also_unmerged(struct index_state *istate,
 411         const char *path, int namelen)
 412 {
 413         int pos = index_name_pos(istate, path, namelen);
 414         struct cache_entry *ce;
 415
 416         if (pos >= 0)
 417                 return pos;
 418
 419         /* maybe unmerged? */
 420         pos = -1 - pos;
 421         if (pos >= istate->cache_nr ||
 422                         compare_name((ce = istate->cache[pos]), path, namelen))
 423                 return -1;
 424
 425         /* order of preference: stage 2, 1, 3 */
 426         if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
 427                         ce_stage((ce = istate->cache[pos + 1])) == 2 &&
 428                         !compare_name(ce, path, namelen))
 429                 pos++;
 430         return pos;
 431 }
 432
 433 static int different_name(struct cache_entry *ce, struct cache_entry *alias)
 434 {
 435         int len = ce_namelen(ce);
 436         return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len);
 437 }
 438
 439 /*
 440  * If we add a filename that aliases in the cache, we will use the
 441  * name that we already have - but we don't want to update the same
 442  * alias twice, because that implies that there were actually two
 443  * different files with aliasing names!
 444  *
 445  * So we use the CE_ADDED flag to verify that the alias was an old
 446  * one before we accept it as
 447  */
 448 static struct cache_entry *create_alias_ce(struct cache_entry *ce, struct cache_entry *alias)
 449 {
 450         int len;
 451         struct cache_entry *new;
 452
 453         if (alias->ce_flags & CE_ADDED)
 454                 die("Will not add file alias '%s' ('%s' already exists in index)", ce->name, alias->name);
 455
 456         /* Ok, create the new entry using the name of the existing alias */
 457         len = ce_namelen(alias);
 458         new = xcalloc(1, cache_entry_size(len));
 459         memcpy(new->name, alias->name, len);
 460         copy_cache_entry(new, ce);
 461         free(ce);
 462         return new;
 463 }
 464
 465 int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 466 {
 467         int size, namelen, was_same;
 468         mode_t st_mode = st->st_mode;
 469         struct cache_entry *ce, *alias;
 470         unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY;
 471         int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND);
 472         int pretend = flags & ADD_CACHE_PRETEND;
 473
 474         if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode))
 475                 die("%s: can only add regular files, symbolic links or git-directories", path);
 476
 477         namelen = strlen(path);
 478         if (S_ISDIR(st_mode)) {
 479                 while (namelen && path[namelen-1] == '/')
 480                         namelen--;
 481         }
 482         size = cache_entry_size(namelen);
 483         ce = xcalloc(1, size);
 484         memcpy(ce->name, path, namelen);
 485         ce->ce_flags = namelen;
 486         fill_stat_cache_info(ce, st);
 487
 488         if (trust_executable_bit && has_symlinks)
 489                 ce->ce_mode = create_ce_mode(st_mode);
 490         else {
 491                 /* If there is an existing entry, pick the mode bits and type
 492                  * from it, otherwise assume unexecutable regular file.
 493                  */
 494                 struct cache_entry *ent;
 495                 int pos = index_name_pos_also_unmerged(istate, path, namelen);
 496
 497                 ent = (0 <= pos) ? istate->cache[pos] : NULL;
 498                 ce->ce_mode = ce_mode_from_stat(ent, st_mode);
 499         }
 500
 501         alias = index_name_exists(istate, ce->name, ce_namelen(ce), ignore_case);
 502         if (alias && !ce_stage(alias) && !ie_match_stat(istate, alias, st, ce_option)) {
 503                 /* Nothing changed, really */
 504                 free(ce);
 505                 ce_mark_uptodate(alias);
 506                 alias->ce_flags |= CE_ADDED;
 507                 return 0;
 508         }
 509         if (index_path(ce->sha1, path, st, 1))
 510                 die("unable to index file %s", path);
 511         if (ignore_case && alias && different_name(ce, alias))
 512                 ce = create_alias_ce(ce, alias);
 513         ce->ce_flags |= CE_ADDED;
 514
 515         /* It was suspected to be recily clean, but it turns out to be Ok */
 516         was_same = (alias &&
 517                     !ce_stage(alias) &&
 518                     !hashcmp(alias->sha1, ce->sha1) &&
 519                     ce->ce_mode == alias->ce_mode);
 520
 521         if (pretend)
 522                 ;
 523         else if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
 524                 die("unable to add %s to index",path);
 525         if (verbose && !was_same)
 526                 printf("add '%s'\n", path);
 527         return 0;
 528 }
 529
 530 int add_file_to_index(struct index_state *istate, const char *path, int flags)
 531 {
 532         struct stat st;
 533         if (lstat(path, &st))
 534                 die("%s: unable to stat (%s)", path, strerror(errno));
 535         return add_to_index(istate, path, &st, flags);
 536 }
 537
 538 struct cache_entry *make_cache_entry(unsigned int mode,
 539                 const unsigned char *sha1, const char *path, int stage,
 540                 int refresh)
 541 {
 542         int size, len;
 543         struct cache_entry *ce;
 544
 545         if (!verify_path(path))
 546                 return NULL;
 547
 548         len = strlen(path);
 549         size = cache_entry_size(len);
 550         ce = xcalloc(1, size);
 551
 552         hashcpy(ce->sha1, sha1);
 553         memcpy(ce->name, path, len);
 554         ce->ce_flags = create_ce_flags(len, stage);
 555         ce->ce_mode = create_ce_mode(mode);
 556
 557         if (refresh)
 558                 return refresh_cache_entry(ce, 0);
 559
 560         return ce;
 561 }
 562
 563 int ce_same_name(struct cache_entry *a, struct cache_entry *b)
 564 {
 565         int len = ce_namelen(a);
 566         return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
 567 }
 568
 569 int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 570 {
 571         const char *match, *name;
 572         int len;
 573
 574         if (!pathspec)
 575                 return 1;
 576
 577         len = ce_namelen(ce);
 578         name = ce->name;
 579         while ((match = *pathspec++) != NULL) {
 580                 int matchlen = strlen(match);
 581                 if (matchlen > len)
 582                         continue;
 583                 if (memcmp(name, match, matchlen))
 584                         continue;
 585                 if (matchlen && name[matchlen-1] == '/')
 586                         return 1;
 587                 if (name[matchlen] == '/' || !name[matchlen])
 588                         return 1;
 589                 if (!matchlen)
 590                         return 1;
 591         }
 592         return 0;
 593 }
 594
 595 /*
 596  * We fundamentally don't like some paths: we don't want
 597  * dot or dot-dot anywhere, and for obvious reasons don't
 598  * want to recurse into ".git" either.
 599  *
 600  * Also, we don't want double slashes or slashes at the
 601  * end that can make pathnames ambiguous.
 602  */
 603 static int verify_dotfile(const char *rest)
 604 {
 605         /*
 606          * The first character was '.', but that
 607          * has already been discarded, we now test
 608          * the rest.
 609          */
 610         switch (*rest) {
 611         /* "." is not allowed */
 612         case '\0': case '/':
 613                 return 0;
 614
 615         /*
 616          * ".git" followed by  NUL or slash is bad. This
 617          * shares the path end test with the ".." case.
 618          */
 619         case 'g':
 620                 if (rest[1] != 'i')
 621                         break;
 622                 if (rest[2] != 't')
 623                         break;
 624                 rest += 2;
 625         /* fallthrough */
 626         case '.':
 627                 if (rest[1] == '\0' || rest[1] == '/')
 628                         return 0;
 629         }
 630         return 1;
 631 }
 632
 633 int verify_path(const char *path)
 634 {
 635         char c;
 636
 637         goto inside;
 638         for (;;) {
 639                 if (!c)
 640                         return 1;
 641                 if (c == '/') {
 642 inside:
 643                         c = *path++;
 644                         switch (c) {
 645                         default:
 646                                 continue;
 647                         case '/': case '\0':
 648                                 break;
 649                         case '.':
 650                                 if (verify_dotfile(path))
 651                                         continue;
 652                         }
 653                         return 0;
 654                 }
 655                 c = *path++;
 656         }
 657 }
 658
 659 /*
 660  * Do we have another file that has the beginning components being a
 661  * proper superset of the name we're trying to add?
 662  */
 663 static int has_file_name(struct index_state *istate,
 664                          const struct cache_entry *ce, int pos, int ok_to_replace)
 665 {
 666         int retval = 0;
 667         int len = ce_namelen(ce);
 668         int stage = ce_stage(ce);
 669         const char *name = ce->name;
 670
 671         while (pos < istate->cache_nr) {
 672                 struct cache_entry *p = istate->cache[pos++];
 673
 674                 if (len >= ce_namelen(p))
 675                         break;
 676                 if (memcmp(name, p->name, len))
 677                         break;
 678                 if (ce_stage(p) != stage)
 679                         continue;
 680                 if (p->name[len] != '/')
 681                         continue;
 682                 if (p->ce_flags & CE_REMOVE)
 683                         continue;
 684                 retval = -1;
 685                 if (!ok_to_replace)
 686                         break;
 687                 remove_index_entry_at(istate, --pos);
 688         }
 689         return retval;
 690 }
 691
 692 /*
 693  * Do we have another file with a pathname that is a proper
 694  * subset of the name we're trying to add?
 695  */
 696 static int has_dir_name(struct index_state *istate,
 697                         const struct cache_entry *ce, int pos, int ok_to_replace)
 698 {
 699         int retval = 0;
 700         int stage = ce_stage(ce);
 701         const char *name = ce->name;
 702         const char *slash = name + ce_namelen(ce);
 703
 704         for (;;) {
 705                 int len;
 706
 707                 for (;;) {
 708                         if (*--slash == '/')
 709                                 break;
 710                         if (slash <= ce->name)
 711                                 return retval;
 712                 }
 713                 len = slash - name;
 714
 715                 pos = index_name_pos(istate, name, create_ce_flags(len, stage));
 716                 if (pos >= 0) {
 717                         /*
 718                          * Found one, but not so fast.  This could
 719                          * be a marker that says "I was here, but
 720                          * I am being removed".  Such an entry is
 721                          * not a part of the resulting tree, and
 722                          * it is Ok to have a directory at the same
 723                          * path.
 724                          */
 725                         if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
 726                                 retval = -1;
 727                                 if (!ok_to_replace)
 728                                         break;
 729                                 remove_index_entry_at(istate, pos);
 730                                 continue;
 731                         }
 732                 }
 733                 else
 734                         pos = -pos-1;
 735
 736                 /*
 737                  * Trivial optimization: if we find an entry that
 738                  * already matches the sub-directory, then we know
 739                  * we're ok, and we can exit.
 740                  */
 741                 while (pos < istate->cache_nr) {
 742                         struct cache_entry *p = istate->cache[pos];
 743                         if ((ce_namelen(p) <= len) ||
 744                             (p->name[len] != '/') ||
 745                             memcmp(p->name, name, len))
 746                                 break; /* not our subdirectory */
 747                         if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
 748                                 /*
 749                                  * p is at the same stage as our entry, and
 750                                  * is a subdirectory of what we are looking
 751                                  * at, so we cannot have conflicts at our
 752                                  * level or anything shorter.
 753                                  */
 754                                 return retval;
 755                         pos++;
 756                 }
 757         }
 758         return retval;
 759 }
 760
 761 /* We may be in a situation where we already have path/file and path
 762  * is being added, or we already have path and path/file is being
 763  * added.  Either one would result in a nonsense tree that has path
 764  * twice when git-write-tree tries to write it out.  Prevent it.
 765  *
 766  * If ok-to-replace is specified, we remove the conflicting entries
 767  * from the cache so the caller should recompute the insert position.
 768  * When this happens, we return non-zero.
 769  */
 770 static int check_file_directory_conflict(struct index_state *istate,
 771                                          const struct cache_entry *ce,
 772                                          int pos, int ok_to_replace)
 773 {
 774         int retval;
 775
 776         /*
 777          * When ce is an "I am going away" entry, we allow it to be added
 778          */
 779         if (ce->ce_flags & CE_REMOVE)
 780                 return 0;
 781
 782         /*
 783          * We check if the path is a sub-path of a subsequent pathname
 784          * first, since removing those will not change the position
 785          * in the array.
 786          */
 787         retval = has_file_name(istate, ce, pos, ok_to_replace);
 788
 789         /*
 790          * Then check if the path might have a clashing sub-directory
 791          * before it.
 792          */
 793         return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 794 }
 795
 796 static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
 797 {
 798         int pos;
 799         int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
 800         int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
 801         int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 802
 803         cache_tree_invalidate_path(istate->cache_tree, ce->name);
 804         pos = index_name_pos(istate, ce->name, ce->ce_flags);
 805
 806         /* existing match? Just replace it. */
 807         if (pos >= 0) {
 808                 replace_index_entry(istate, pos, ce);
 809                 return 0;
 810         }
 811         pos = -pos-1;
 812
 813         /*
 814          * Inserting a merged entry ("stage 0") into the index
 815          * will always replace all non-merged entries..
 816          */
 817         if (pos < istate->cache_nr && ce_stage(ce) == 0) {
 818                 while (ce_same_name(istate->cache[pos], ce)) {
 819                         ok_to_add = 1;
 820                         if (!remove_index_entry_at(istate, pos))
 821                                 break;
 822                 }
 823         }
 824
 825         if (!ok_to_add)
 826                 return -1;
 827         if (!verify_path(ce->name))
 828                 return -1;
 829
 830         if (!skip_df_check &&
 831             check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
 832                 if (!ok_to_replace)
 833                         return error("'%s' appears as both a file and as a directory",
 834                                      ce->name);
 835                 pos = index_name_pos(istate, ce->name, ce->ce_flags);
 836                 pos = -pos-1;
 837         }
 838         return pos + 1;
 839 }
 840
 841 int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 842 {
 843         int pos;
 844
 845         if (option & ADD_CACHE_JUST_APPEND)
 846                 pos = istate->cache_nr;
 847         else {
 848                 int ret;
 849                 ret = add_index_entry_with_check(istate, ce, option);
 850                 if (ret <= 0)
 851                         return ret;
 852                 pos = ret - 1;
 853         }
 854
 855         /* Make sure the array is big enough .. */
 856         if (istate->cache_nr == istate->cache_alloc) {
 857                 istate->cache_alloc = alloc_nr(istate->cache_alloc);
 858                 istate->cache = xrealloc(istate->cache,
 859                                         istate->cache_alloc * sizeof(struct cache_entry *));
 860         }
 861
 862         /* Add it in.. */
 863         istate->cache_nr++;
 864         if (istate->cache_nr > pos + 1)
 865                 memmove(istate->cache + pos + 1,
 866                         istate->cache + pos,
 867                         (istate->cache_nr - pos - 1) * sizeof(ce));
 868         set_index_entry(istate, pos, ce);
 869         istate->cache_changed = 1;
 870         return 0;
 871 }
 872
 873 /*
 874  * "refresh" does not calculate a new sha1 file or bring the
 875  * cache up-to-date for mode/content changes. But what it
 876  * _does_ do is to "re-match" the stat information of a file
 877  * with the cache, so that you can refresh the cache for a
 878  * file that hasn't been changed but where the stat entry is
 879  * out of date.
 880  *
 881  * For example, you'd want to do this after doing a "git-read-tree",
 882  * to link up the stat cache details with the proper files.
 883  */
 884 static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 885                                              struct cache_entry *ce,
 886                                              unsigned int options, int *err)
 887 {
 888         struct stat st;
 889         struct cache_entry *updated;
 890         int changed, size;
 891         int ignore_valid = options & CE_MATCH_IGNORE_VALID;
 892
 893         if (ce_uptodate(ce))
 894                 return ce;
 895
 896         if (lstat(ce->name, &st) < 0) {
 897                 if (err)
 898                         *err = errno;
 899                 return NULL;
 900         }
 901
 902         changed = ie_match_stat(istate, ce, &st, options);
 903         if (!changed) {
 904                 /*
 905                  * The path is unchanged.  If we were told to ignore
 906                  * valid bit, then we did the actual stat check and
 907                  * found that the entry is unmodified.  If the entry
 908                  * is not marked VALID, this is the place to mark it
 909                  * valid again, under "assume unchanged" mode.
 910                  */
 911                 if (ignore_valid && assume_unchanged &&
 912                     !(ce->ce_flags & CE_VALID))
 913                         ; /* mark this one VALID again */
 914                 else {
 915                         /*
 916                          * We do not mark the index itself "modified"
 917                          * because CE_UPTODATE flag is in-core only;
 918                          * we are not going to write this change out.
 919                          */
 920                         ce_mark_uptodate(ce);
 921                         return ce;
 922                 }
 923         }
 924
 925         if (ie_modified(istate, ce, &st, options)) {
 926                 if (err)
 927                         *err = EINVAL;
 928                 return NULL;
 929         }
 930
 931         size = ce_size(ce);
 932         updated = xmalloc(size);
 933         memcpy(updated, ce, size);
 934         fill_stat_cache_info(updated, &st);
 935         /*
 936          * If ignore_valid is not set, we should leave CE_VALID bit
 937          * alone.  Otherwise, paths marked with --no-assume-unchanged
 938          * (i.e. things to be edited) will reacquire CE_VALID bit
 939          * automatically, which is not really what we want.
 940          */
 941         if (!ignore_valid && assume_unchanged &&
 942             !(ce->ce_flags & CE_VALID))
 943                 updated->ce_flags &= ~CE_VALID;
 944
 945         return updated;
 946 }
 947
 948 int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
 949 {
 950         int i;
 951         int has_errors = 0;
 952         int really = (flags & REFRESH_REALLY) != 0;
 953         int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
 954         int quiet = (flags & REFRESH_QUIET) != 0;
 955         int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
 956         unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0;
 957
 958         for (i = 0; i < istate->cache_nr; i++) {
 959                 struct cache_entry *ce, *new;
 960                 int cache_errno = 0;
 961
 962                 ce = istate->cache[i];
 963                 if (ce_stage(ce)) {
 964                         while ((i < istate->cache_nr) &&
 965                                ! strcmp(istate->cache[i]->name, ce->name))
 966                                 i++;
 967                         i--;
 968                         if (allow_unmerged)
 969                                 continue;
 970                         printf("%s: needs merge\n", ce->name);
 971                         has_errors = 1;
 972                         continue;
 973                 }
 974
 975                 if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
 976                         continue;
 977
 978                 new = refresh_cache_ent(istate, ce, options, &cache_errno);
 979                 if (new == ce)
 980                         continue;
 981                 if (!new) {
 982                         if (not_new && cache_errno == ENOENT)
 983                                 continue;
 984                         if (really && cache_errno == EINVAL) {
 985                                 /* If we are doing --really-refresh that
 986                                  * means the index is not valid anymore.
 987                                  */
 988                                 ce->ce_flags &= ~CE_VALID;
 989                                 istate->cache_changed = 1;
 990                         }
 991                         if (quiet)
 992                                 continue;
 993                         printf("%s: needs update\n", ce->name);
 994                         has_errors = 1;
 995                         continue;
 996                 }
 997
 998                 replace_index_entry(istate, i, new);
 999         }
1000         return has_errors;
1001 }
1002
1003 struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
1004 {
1005         return refresh_cache_ent(&the_index, ce, really, NULL);
1006 }
1007
1008 static int verify_hdr(struct cache_header *hdr, unsigned long size)
1009 {
1010         SHA_CTX c;
1011         unsigned char sha1[20];
1012
1013         if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
1014                 return error("bad signature");
1015         if (hdr->hdr_version != htonl(2))
1016                 return error("bad index version");
1017         SHA1_Init(&c);
1018         SHA1_Update(&c, hdr, size - 20);
1019         SHA1_Final(sha1, &c);
1020         if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1021                 return error("bad index file sha1 signature");
1022         return 0;
1023 }
1024
1025 static int read_index_extension(struct index_state *istate,
1026                                 const char *ext, void *data, unsigned long sz)
1027 {
1028         switch (CACHE_EXT(ext)) {
1029         case CACHE_EXT_TREE:
1030                 istate->cache_tree = cache_tree_read(data, sz);
1031                 break;
1032         default:
1033                 if (*ext < 'A' || 'Z' < *ext)
1034                         return error("index uses %.4s extension, which we do not understand",
1035                                      ext);
1036                 fprintf(stderr, "ignoring %.4s extension\n", ext);
1037                 break;
1038         }
1039         return 0;
1040 }
1041
1042 int read_index(struct index_state *istate)
1043 {
1044         return read_index_from(istate, get_index_file());
1045 }
1046
1047 static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
1048 {
1049         size_t len;
1050
1051         ce->ce_ctime = ntohl(ondisk->ctime.sec);
1052         ce->ce_mtime = ntohl(ondisk->mtime.sec);
1053         ce->ce_dev   = ntohl(ondisk->dev);
1054         ce->ce_ino   = ntohl(ondisk->ino);
1055         ce->ce_mode  = ntohl(ondisk->mode);
1056         ce->ce_uid   = ntohl(ondisk->uid);
1057         ce->ce_gid   = ntohl(ondisk->gid);
1058         ce->ce_size  = ntohl(ondisk->size);
1059         /* On-disk flags are just 16 bits */
1060         ce->ce_flags = ntohs(ondisk->flags);
1061         hashcpy(ce->sha1, ondisk->sha1);
1062
1063         len = ce->ce_flags & CE_NAMEMASK;
1064         if (len == CE_NAMEMASK)
1065                 len = strlen(ondisk->name);
1066         /*
1067          * NEEDSWORK: If the original index is crafted, this copy could
1068          * go unchecked.
1069          */
1070         memcpy(ce->name, ondisk->name, len + 1);
1071 }
1072
1073 static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1074 {
1075         long per_entry;
1076
1077         per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1078
1079         /*
1080          * Alignment can cause differences. This should be "alignof", but
1081          * since that's a gcc'ism, just use the size of a pointer.
1082          */
1083         per_entry += sizeof(void *);
1084         return ondisk_size + entries*per_entry;
1085 }
1086
1087 /* remember to discard_cache() before reading a different cache! */
1088 int read_index_from(struct index_state *istate, const char *path)
1089 {
1090         int fd, i;
1091         struct stat st;
1092         unsigned long src_offset, dst_offset;
1093         struct cache_header *hdr;
1094         void *mmap;
1095         size_t mmap_size;
1096
1097         errno = EBUSY;
1098         if (istate->alloc)
1099                 return istate->cache_nr;
1100
1101         errno = ENOENT;
1102         istate->timestamp = 0;
1103         fd = open(path, O_RDONLY);
1104         if (fd < 0) {
1105                 if (errno == ENOENT)
1106                         return 0;
1107                 die("index file open failed (%s)", strerror(errno));
1108         }
1109
1110         if (fstat(fd, &st))
1111                 die("cannot stat the open index (%s)", strerror(errno));
1112
1113         errno = EINVAL;
1114         mmap_size = xsize_t(st.st_size);
1115         if (mmap_size < sizeof(struct cache_header) + 20)
1116                 die("index file smaller than expected");
1117
1118         mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
1119         close(fd);
1120         if (mmap == MAP_FAILED)
1121                 die("unable to map index file");
1122
1123         hdr = mmap;
1124         if (verify_hdr(hdr, mmap_size) < 0)
1125                 goto unmap;
1126
1127         istate->cache_nr = ntohl(hdr->hdr_entries);
1128         istate->cache_alloc = alloc_nr(istate->cache_nr);
1129         istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
1130
1131         /*
1132          * The disk format is actually larger than the in-memory format,
1133          * due to space for nsec etc, so even though the in-memory one
1134          * has room for a few  more flags, we can allocate using the same
1135          * index size
1136          */
1137         istate->alloc = xmalloc(estimate_cache_size(mmap_size, istate->cache_nr));
1138
1139         src_offset = sizeof(*hdr);
1140         dst_offset = 0;
1141         for (i = 0; i < istate->cache_nr; i++) {
1142                 struct ondisk_cache_entry *disk_ce;
1143                 struct cache_entry *ce;
1144
1145                 disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1146                 ce = (struct cache_entry *)((char *)istate->alloc + dst_offset);
1147                 convert_from_disk(disk_ce, ce);
1148                 set_index_entry(istate, i, ce);
1149
1150                 src_offset += ondisk_ce_size(ce);
1151                 dst_offset += ce_size(ce);
1152         }
1153         istate->timestamp = st.st_mtime;
1154         while (src_offset <= mmap_size - 20 - 8) {
1155                 /* After an array of active_nr index entries,
1156                  * there can be arbitrary number of extended
1157                  * sections, each of which is prefixed with
1158                  * extension name (4-byte) and section length
1159                  * in 4-byte network byte order.
1160                  */
1161                 unsigned long extsize;
1162                 memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1163                 extsize = ntohl(extsize);
1164                 if (read_index_extension(istate,
1165                                          (const char *) mmap + src_offset,
1166                                          (char *) mmap + src_offset + 8,
1167                                          extsize) < 0)
1168                         goto unmap;
1169                 src_offset += 8;
1170                 src_offset += extsize;
1171         }
1172         munmap(mmap, mmap_size);
1173         return istate->cache_nr;
1174
1175 unmap:
1176         munmap(mmap, mmap_size);
1177         errno = EINVAL;
1178         die("index file corrupt");
1179 }
1180
1181 int discard_index(struct index_state *istate)
1182 {
1183         istate->cache_nr = 0;
1184         istate->cache_changed = 0;
1185         istate->timestamp = 0;
1186         free_hash(&istate->name_hash);
1187         cache_tree_free(&(istate->cache_tree));
1188         free(istate->alloc);
1189         istate->alloc = NULL;
1190
1191         /* no need to throw away allocated active_cache */
1192         return 0;
1193 }
1194
1195 int unmerged_index(const struct index_state *istate)
1196 {
1197         int i;
1198         for (i = 0; i < istate->cache_nr; i++) {
1199                 if (ce_stage(istate->cache[i]))
1200                         return 1;
1201         }
1202         return 0;
1203 }
1204
1205 #define WRITE_BUFFER_SIZE 8192
1206 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1207 static unsigned long write_buffer_len;
1208
1209 static int ce_write_flush(SHA_CTX *context, int fd)
1210 {
1211         unsigned int buffered = write_buffer_len;
1212         if (buffered) {
1213                 SHA1_Update(context, write_buffer, buffered);
1214                 if (write_in_full(fd, write_buffer, buffered) != buffered)
1215                         return -1;
1216                 write_buffer_len = 0;
1217         }
1218         return 0;
1219 }
1220
1221 static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
1222 {
1223         while (len) {
1224                 unsigned int buffered = write_buffer_len;
1225                 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1226                 if (partial > len)
1227                         partial = len;
1228                 memcpy(write_buffer + buffered, data, partial);
1229                 buffered += partial;
1230                 if (buffered == WRITE_BUFFER_SIZE) {
1231                         write_buffer_len = buffered;
1232                         if (ce_write_flush(context, fd))
1233                                 return -1;
1234                         buffered = 0;
1235                 }
1236                 write_buffer_len = buffered;
1237                 len -= partial;
1238                 data = (char *) data + partial;
1239         }
1240         return 0;
1241 }
1242
1243 static int write_index_ext_header(SHA_CTX *context, int fd,
1244                                   unsigned int ext, unsigned int sz)
1245 {
1246         ext = htonl(ext);
1247         sz = htonl(sz);
1248         return ((ce_write(context, fd, &ext, 4) < 0) ||
1249                 (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1250 }
1251
1252 static int ce_flush(SHA_CTX *context, int fd)
1253 {
1254         unsigned int left = write_buffer_len;
1255
1256         if (left) {
1257                 write_buffer_len = 0;
1258                 SHA1_Update(context, write_buffer, left);
1259         }
1260
1261         /* Flush first if not enough space for SHA1 signature */
1262         if (left + 20 > WRITE_BUFFER_SIZE) {
1263                 if (write_in_full(fd, write_buffer, left) != left)
1264                         return -1;
1265                 left = 0;
1266         }
1267
1268         /* Append the SHA1 signature at the end */
1269         SHA1_Final(write_buffer + left, context);
1270         left += 20;
1271         return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1272 }
1273
1274 static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1275 {
1276         /*
1277          * The only thing we care about in this function is to smudge the
1278          * falsely clean entry due to touch-update-touch race, so we leave
1279          * everything else as they are.  We are called for entries whose
1280          * ce_mtime match the index file mtime.
1281          */
1282         struct stat st;
1283
1284         if (lstat(ce->name, &st) < 0)
1285                 return;
1286         if (ce_match_stat_basic(ce, &st))
1287                 return;
1288         if (ce_modified_check_fs(ce, &st)) {
1289                 /* This is "racily clean"; smudge it.  Note that this
1290                  * is a tricky code.  At first glance, it may appear
1291                  * that it can break with this sequence:
1292                  *
1293                  * $ echo xyzzy >frotz
1294                  * $ git-update-index --add frotz
1295                  * $ : >frotz
1296                  * $ sleep 3
1297                  * $ echo filfre >nitfol
1298                  * $ git-update-index --add nitfol
1299                  *
1300                  * but it does not.  When the second update-index runs,
1301                  * it notices that the entry "frotz" has the same timestamp
1302                  * as index, and if we were to smudge it by resetting its
1303                  * size to zero here, then the object name recorded
1304                  * in index is the 6-byte file but the cached stat information
1305                  * becomes zero --- which would then match what we would
1306                  * obtain from the filesystem next time we stat("frotz").
1307                  *
1308                  * However, the second update-index, before calling
1309                  * this function, notices that the cached size is 6
1310                  * bytes and what is on the filesystem is an empty
1311                  * file, and never calls us, so the cached size information
1312                  * for "frotz" stays 6 which does not match the filesystem.
1313                  */
1314                 ce->ce_size = 0;
1315         }
1316 }
1317
1318 static int ce_write_entry(SHA_CTX *c, int fd, struct cache_entry *ce)
1319 {
1320         int size = ondisk_ce_size(ce);
1321         struct ondisk_cache_entry *ondisk = xcalloc(1, size);
1322
1323         ondisk->ctime.sec = htonl(ce->ce_ctime);
1324         ondisk->ctime.nsec = 0;
1325         ondisk->mtime.sec = htonl(ce->ce_mtime);
1326         ondisk->mtime.nsec = 0;
1327         ondisk->dev  = htonl(ce->ce_dev);
1328         ondisk->ino  = htonl(ce->ce_ino);
1329         ondisk->mode = htonl(ce->ce_mode);
1330         ondisk->uid  = htonl(ce->ce_uid);
1331         ondisk->gid  = htonl(ce->ce_gid);
1332         ondisk->size = htonl(ce->ce_size);
1333         hashcpy(ondisk->sha1, ce->sha1);
1334         ondisk->flags = htons(ce->ce_flags);
1335         memcpy(ondisk->name, ce->name, ce_namelen(ce));
1336
1337         return ce_write(c, fd, ondisk, size);
1338 }
1339
1340 int write_index(const struct index_state *istate, int newfd)
1341 {
1342         SHA_CTX c;
1343         struct cache_header hdr;
1344         int i, err, removed;
1345         struct cache_entry **cache = istate->cache;
1346         int entries = istate->cache_nr;
1347
1348         for (i = removed = 0; i < entries; i++)
1349                 if (cache[i]->ce_flags & CE_REMOVE)
1350                         removed++;
1351
1352         hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1353         hdr.hdr_version = htonl(2);
1354         hdr.hdr_entries = htonl(entries - removed);
1355
1356         SHA1_Init(&c);
1357         if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1358                 return -1;
1359
1360         for (i = 0; i < entries; i++) {
1361                 struct cache_entry *ce = cache[i];
1362                 if (ce->ce_flags & CE_REMOVE)
1363                         continue;
1364                 if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
1365                         ce_smudge_racily_clean_entry(ce);
1366                 if (ce_write_entry(&c, newfd, ce) < 0)
1367                         return -1;
1368         }
1369
1370         /* Write extension data here */
1371         if (istate->cache_tree) {
1372                 struct strbuf sb;
1373
1374                 strbuf_init(&sb, 0);
1375                 cache_tree_write(&sb, istate->cache_tree);
1376                 err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1377                         || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1378                 strbuf_release(&sb);
1379                 if (err)
1380                         return -1;
1381         }
1382         return ce_flush(&c, newfd);
1383 }