Merge branch 'mc/prefix'
[git/git.git] / 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 unsigned int hash_name(const char *name, int namelen)
27 {
28 unsigned int hash = 0x123;
29
30 do {
31 unsigned char c = *name++;
32 hash = hash*101 + c;
33 } while (--namelen);
34 return hash;
35 }
36
37 static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
38 {
39 void **pos;
40 unsigned int hash = hash_name(ce->name, ce_namelen(ce));
41
42 pos = insert_hash(hash, ce, &istate->name_hash);
43 if (pos) {
44 ce->next = *pos;
45 *pos = ce;
46 }
47 }
48
49 static void lazy_init_name_hash(struct index_state *istate)
50 {
51 int nr;
52
53 if (istate->name_hash_initialized)
54 return;
55 for (nr = 0; nr < istate->cache_nr; nr++)
56 hash_index_entry(istate, istate->cache[nr]);
57 istate->name_hash_initialized = 1;
58 }
59
60 static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
61 {
62 istate->cache[nr] = ce;
63 if (istate->name_hash_initialized)
64 hash_index_entry(istate, ce);
65 }
66
67 /*
68 * We don't actually *remove* it, we can just mark it invalid so that
69 * we won't find it in lookups.
70 *
71 * Not only would we have to search the lists (simple enough), but
72 * we'd also have to rehash other hash buckets in case this makes the
73 * hash bucket empty (common). So it's much better to just mark
74 * it.
75 */
76 static void remove_hash_entry(struct index_state *istate, struct cache_entry *ce)
77 {
78 ce->ce_flags |= CE_UNHASHED;
79 }
80
81 static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
82 {
83 struct cache_entry *old = istate->cache[nr];
84
85 if (ce != old) {
86 remove_hash_entry(istate, old);
87 set_index_entry(istate, nr, ce);
88 }
89 istate->cache_changed = 1;
90 }
91
92 int index_name_exists(struct index_state *istate, const char *name, int namelen)
93 {
94 unsigned int hash = hash_name(name, namelen);
95 struct cache_entry *ce;
96
97 lazy_init_name_hash(istate);
98 ce = lookup_hash(hash, &istate->name_hash);
99
100 while (ce) {
101 if (!(ce->ce_flags & CE_UNHASHED)) {
102 if (!cache_name_compare(name, namelen, ce->name, ce->ce_flags))
103 return 1;
104 }
105 ce = ce->next;
106 }
107 return 0;
108 }
109
110 /*
111 * This only updates the "non-critical" parts of the directory
112 * cache, ie the parts that aren't tracked by GIT, and only used
113 * to validate the cache.
114 */
115 void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
116 {
117 ce->ce_ctime = st->st_ctime;
118 ce->ce_mtime = st->st_mtime;
119 ce->ce_dev = st->st_dev;
120 ce->ce_ino = st->st_ino;
121 ce->ce_uid = st->st_uid;
122 ce->ce_gid = st->st_gid;
123 ce->ce_size = st->st_size;
124
125 if (assume_unchanged)
126 ce->ce_flags |= CE_VALID;
127
128 if (S_ISREG(st->st_mode))
129 ce_mark_uptodate(ce);
130 }
131
132 static int ce_compare_data(struct cache_entry *ce, struct stat *st)
133 {
134 int match = -1;
135 int fd = open(ce->name, O_RDONLY);
136
137 if (fd >= 0) {
138 unsigned char sha1[20];
139 if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
140 match = hashcmp(sha1, ce->sha1);
141 /* index_fd() closed the file descriptor already */
142 }
143 return match;
144 }
145
146 static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
147 {
148 int match = -1;
149 char *target;
150 void *buffer;
151 unsigned long size;
152 enum object_type type;
153 int len;
154
155 target = xmalloc(expected_size);
156 len = readlink(ce->name, target, expected_size);
157 if (len != expected_size) {
158 free(target);
159 return -1;
160 }
161 buffer = read_sha1_file(ce->sha1, &type, &size);
162 if (!buffer) {
163 free(target);
164 return -1;
165 }
166 if (size == expected_size)
167 match = memcmp(buffer, target, size);
168 free(buffer);
169 free(target);
170 return match;
171 }
172
173 static int ce_compare_gitlink(struct cache_entry *ce)
174 {
175 unsigned char sha1[20];
176
177 /*
178 * We don't actually require that the .git directory
179 * under GITLINK directory be a valid git directory. It
180 * might even be missing (in case nobody populated that
181 * sub-project).
182 *
183 * If so, we consider it always to match.
184 */
185 if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
186 return 0;
187 return hashcmp(sha1, ce->sha1);
188 }
189
190 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
191 {
192 switch (st->st_mode & S_IFMT) {
193 case S_IFREG:
194 if (ce_compare_data(ce, st))
195 return DATA_CHANGED;
196 break;
197 case S_IFLNK:
198 if (ce_compare_link(ce, xsize_t(st->st_size)))
199 return DATA_CHANGED;
200 break;
201 case S_IFDIR:
202 if (S_ISGITLINK(ce->ce_mode))
203 return 0;
204 default:
205 return TYPE_CHANGED;
206 }
207 return 0;
208 }
209
210 static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
211 {
212 unsigned int changed = 0;
213
214 if (ce->ce_flags & CE_REMOVE)
215 return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED;
216
217 switch (ce->ce_mode & S_IFMT) {
218 case S_IFREG:
219 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
220 /* We consider only the owner x bit to be relevant for
221 * "mode changes"
222 */
223 if (trust_executable_bit &&
224 (0100 & (ce->ce_mode ^ st->st_mode)))
225 changed |= MODE_CHANGED;
226 break;
227 case S_IFLNK:
228 if (!S_ISLNK(st->st_mode) &&
229 (has_symlinks || !S_ISREG(st->st_mode)))
230 changed |= TYPE_CHANGED;
231 break;
232 case S_IFGITLINK:
233 if (!S_ISDIR(st->st_mode))
234 changed |= TYPE_CHANGED;
235 else if (ce_compare_gitlink(ce))
236 changed |= DATA_CHANGED;
237 return changed;
238 default:
239 die("internal error: ce_mode is %o", ce->ce_mode);
240 }
241 if (ce->ce_mtime != (unsigned int) st->st_mtime)
242 changed |= MTIME_CHANGED;
243 if (ce->ce_ctime != (unsigned int) st->st_ctime)
244 changed |= CTIME_CHANGED;
245
246 if (ce->ce_uid != (unsigned int) st->st_uid ||
247 ce->ce_gid != (unsigned int) st->st_gid)
248 changed |= OWNER_CHANGED;
249 if (ce->ce_ino != (unsigned int) st->st_ino)
250 changed |= INODE_CHANGED;
251
252 #ifdef USE_STDEV
253 /*
254 * st_dev breaks on network filesystems where different
255 * clients will have different views of what "device"
256 * the filesystem is on
257 */
258 if (ce->ce_dev != (unsigned int) st->st_dev)
259 changed |= INODE_CHANGED;
260 #endif
261
262 if (ce->ce_size != (unsigned int) st->st_size)
263 changed |= DATA_CHANGED;
264
265 return changed;
266 }
267
268 static int is_racy_timestamp(struct index_state *istate, struct cache_entry *ce)
269 {
270 return (istate->timestamp &&
271 ((unsigned int)istate->timestamp) <= ce->ce_mtime);
272 }
273
274 int ie_match_stat(struct index_state *istate,
275 struct cache_entry *ce, struct stat *st,
276 unsigned int options)
277 {
278 unsigned int changed;
279 int ignore_valid = options & CE_MATCH_IGNORE_VALID;
280 int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY;
281
282 /*
283 * If it's marked as always valid in the index, it's
284 * valid whatever the checked-out copy says.
285 */
286 if (!ignore_valid && (ce->ce_flags & CE_VALID))
287 return 0;
288
289 changed = ce_match_stat_basic(ce, st);
290
291 /*
292 * Within 1 second of this sequence:
293 * echo xyzzy >file && git-update-index --add file
294 * running this command:
295 * echo frotz >file
296 * would give a falsely clean cache entry. The mtime and
297 * length match the cache, and other stat fields do not change.
298 *
299 * We could detect this at update-index time (the cache entry
300 * being registered/updated records the same time as "now")
301 * and delay the return from git-update-index, but that would
302 * effectively mean we can make at most one commit per second,
303 * which is not acceptable. Instead, we check cache entries
304 * whose mtime are the same as the index file timestamp more
305 * carefully than others.
306 */
307 if (!changed && is_racy_timestamp(istate, ce)) {
308 if (assume_racy_is_modified)
309 changed |= DATA_CHANGED;
310 else
311 changed |= ce_modified_check_fs(ce, st);
312 }
313
314 return changed;
315 }
316
317 int ie_modified(struct index_state *istate,
318 struct cache_entry *ce, struct stat *st, unsigned int options)
319 {
320 int changed, changed_fs;
321
322 changed = ie_match_stat(istate, ce, st, options);
323 if (!changed)
324 return 0;
325 /*
326 * If the mode or type has changed, there's no point in trying
327 * to refresh the entry - it's not going to match
328 */
329 if (changed & (MODE_CHANGED | TYPE_CHANGED))
330 return changed;
331
332 /* Immediately after read-tree or update-index --cacheinfo,
333 * the length field is zero. For other cases the ce_size
334 * should match the SHA1 recorded in the index entry.
335 */
336 if ((changed & DATA_CHANGED) && ce->ce_size != 0)
337 return changed;
338
339 changed_fs = ce_modified_check_fs(ce, st);
340 if (changed_fs)
341 return changed | changed_fs;
342 return 0;
343 }
344
345 int base_name_compare(const char *name1, int len1, int mode1,
346 const char *name2, int len2, int mode2)
347 {
348 unsigned char c1, c2;
349 int len = len1 < len2 ? len1 : len2;
350 int cmp;
351
352 cmp = memcmp(name1, name2, len);
353 if (cmp)
354 return cmp;
355 c1 = name1[len];
356 c2 = name2[len];
357 if (!c1 && S_ISDIR(mode1))
358 c1 = '/';
359 if (!c2 && S_ISDIR(mode2))
360 c2 = '/';
361 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
362 }
363
364 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
365 {
366 int len1 = flags1 & CE_NAMEMASK;
367 int len2 = flags2 & CE_NAMEMASK;
368 int len = len1 < len2 ? len1 : len2;
369 int cmp;
370
371 cmp = memcmp(name1, name2, len);
372 if (cmp)
373 return cmp;
374 if (len1 < len2)
375 return -1;
376 if (len1 > len2)
377 return 1;
378
379 /* Compare stages */
380 flags1 &= CE_STAGEMASK;
381 flags2 &= CE_STAGEMASK;
382
383 if (flags1 < flags2)
384 return -1;
385 if (flags1 > flags2)
386 return 1;
387 return 0;
388 }
389
390 int index_name_pos(struct index_state *istate, const char *name, int namelen)
391 {
392 int first, last;
393
394 first = 0;
395 last = istate->cache_nr;
396 while (last > first) {
397 int next = (last + first) >> 1;
398 struct cache_entry *ce = istate->cache[next];
399 int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
400 if (!cmp)
401 return next;
402 if (cmp < 0) {
403 last = next;
404 continue;
405 }
406 first = next+1;
407 }
408 return -first-1;
409 }
410
411 /* Remove entry, return true if there are more entries to go.. */
412 int remove_index_entry_at(struct index_state *istate, int pos)
413 {
414 struct cache_entry *ce = istate->cache[pos];
415
416 remove_hash_entry(istate, ce);
417 istate->cache_changed = 1;
418 istate->cache_nr--;
419 if (pos >= istate->cache_nr)
420 return 0;
421 memmove(istate->cache + pos,
422 istate->cache + pos + 1,
423 (istate->cache_nr - pos) * sizeof(struct cache_entry *));
424 return 1;
425 }
426
427 int remove_file_from_index(struct index_state *istate, const char *path)
428 {
429 int pos = index_name_pos(istate, path, strlen(path));
430 if (pos < 0)
431 pos = -pos-1;
432 cache_tree_invalidate_path(istate->cache_tree, path);
433 while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
434 remove_index_entry_at(istate, pos);
435 return 0;
436 }
437
438 static int compare_name(struct cache_entry *ce, const char *path, int namelen)
439 {
440 return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
441 }
442
443 static int index_name_pos_also_unmerged(struct index_state *istate,
444 const char *path, int namelen)
445 {
446 int pos = index_name_pos(istate, path, namelen);
447 struct cache_entry *ce;
448
449 if (pos >= 0)
450 return pos;
451
452 /* maybe unmerged? */
453 pos = -1 - pos;
454 if (pos >= istate->cache_nr ||
455 compare_name((ce = istate->cache[pos]), path, namelen))
456 return -1;
457
458 /* order of preference: stage 2, 1, 3 */
459 if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
460 ce_stage((ce = istate->cache[pos + 1])) == 2 &&
461 !compare_name(ce, path, namelen))
462 pos++;
463 return pos;
464 }
465
466 int add_file_to_index(struct index_state *istate, const char *path, int verbose)
467 {
468 int size, namelen, pos;
469 struct stat st;
470 struct cache_entry *ce;
471 unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_RACY_IS_DIRTY;
472
473 if (lstat(path, &st))
474 die("%s: unable to stat (%s)", path, strerror(errno));
475
476 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
477 die("%s: can only add regular files, symbolic links or git-directories", path);
478
479 namelen = strlen(path);
480 if (S_ISDIR(st.st_mode)) {
481 while (namelen && path[namelen-1] == '/')
482 namelen--;
483 }
484 size = cache_entry_size(namelen);
485 ce = xcalloc(1, size);
486 memcpy(ce->name, path, namelen);
487 ce->ce_flags = namelen;
488 fill_stat_cache_info(ce, &st);
489
490 if (trust_executable_bit && has_symlinks)
491 ce->ce_mode = create_ce_mode(st.st_mode);
492 else {
493 /* If there is an existing entry, pick the mode bits and type
494 * from it, otherwise assume unexecutable regular file.
495 */
496 struct cache_entry *ent;
497 int pos = index_name_pos_also_unmerged(istate, path, namelen);
498
499 ent = (0 <= pos) ? istate->cache[pos] : NULL;
500 ce->ce_mode = ce_mode_from_stat(ent, st.st_mode);
501 }
502
503 pos = index_name_pos(istate, ce->name, namelen);
504 if (0 <= pos &&
505 !ce_stage(istate->cache[pos]) &&
506 !ie_match_stat(istate, istate->cache[pos], &st, ce_option)) {
507 /* Nothing changed, really */
508 free(ce);
509 ce_mark_uptodate(istate->cache[pos]);
510 return 0;
511 }
512
513 if (index_path(ce->sha1, path, &st, 1))
514 die("unable to index file %s", path);
515 if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
516 die("unable to add %s to index",path);
517 if (verbose)
518 printf("add '%s'\n", path);
519 return 0;
520 }
521
522 struct cache_entry *make_cache_entry(unsigned int mode,
523 const unsigned char *sha1, const char *path, int stage,
524 int refresh)
525 {
526 int size, len;
527 struct cache_entry *ce;
528
529 if (!verify_path(path))
530 return NULL;
531
532 len = strlen(path);
533 size = cache_entry_size(len);
534 ce = xcalloc(1, size);
535
536 hashcpy(ce->sha1, sha1);
537 memcpy(ce->name, path, len);
538 ce->ce_flags = create_ce_flags(len, stage);
539 ce->ce_mode = create_ce_mode(mode);
540
541 if (refresh)
542 return refresh_cache_entry(ce, 0);
543
544 return ce;
545 }
546
547 int ce_same_name(struct cache_entry *a, struct cache_entry *b)
548 {
549 int len = ce_namelen(a);
550 return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
551 }
552
553 int ce_path_match(const struct cache_entry *ce, const char **pathspec)
554 {
555 const char *match, *name;
556 int len;
557
558 if (!pathspec)
559 return 1;
560
561 len = ce_namelen(ce);
562 name = ce->name;
563 while ((match = *pathspec++) != NULL) {
564 int matchlen = strlen(match);
565 if (matchlen > len)
566 continue;
567 if (memcmp(name, match, matchlen))
568 continue;
569 if (matchlen && name[matchlen-1] == '/')
570 return 1;
571 if (name[matchlen] == '/' || !name[matchlen])
572 return 1;
573 if (!matchlen)
574 return 1;
575 }
576 return 0;
577 }
578
579 /*
580 * We fundamentally don't like some paths: we don't want
581 * dot or dot-dot anywhere, and for obvious reasons don't
582 * want to recurse into ".git" either.
583 *
584 * Also, we don't want double slashes or slashes at the
585 * end that can make pathnames ambiguous.
586 */
587 static int verify_dotfile(const char *rest)
588 {
589 /*
590 * The first character was '.', but that
591 * has already been discarded, we now test
592 * the rest.
593 */
594 switch (*rest) {
595 /* "." is not allowed */
596 case '\0': case '/':
597 return 0;
598
599 /*
600 * ".git" followed by NUL or slash is bad. This
601 * shares the path end test with the ".." case.
602 */
603 case 'g':
604 if (rest[1] != 'i')
605 break;
606 if (rest[2] != 't')
607 break;
608 rest += 2;
609 /* fallthrough */
610 case '.':
611 if (rest[1] == '\0' || rest[1] == '/')
612 return 0;
613 }
614 return 1;
615 }
616
617 int verify_path(const char *path)
618 {
619 char c;
620
621 goto inside;
622 for (;;) {
623 if (!c)
624 return 1;
625 if (c == '/') {
626 inside:
627 c = *path++;
628 switch (c) {
629 default:
630 continue;
631 case '/': case '\0':
632 break;
633 case '.':
634 if (verify_dotfile(path))
635 continue;
636 }
637 return 0;
638 }
639 c = *path++;
640 }
641 }
642
643 /*
644 * Do we have another file that has the beginning components being a
645 * proper superset of the name we're trying to add?
646 */
647 static int has_file_name(struct index_state *istate,
648 const struct cache_entry *ce, int pos, int ok_to_replace)
649 {
650 int retval = 0;
651 int len = ce_namelen(ce);
652 int stage = ce_stage(ce);
653 const char *name = ce->name;
654
655 while (pos < istate->cache_nr) {
656 struct cache_entry *p = istate->cache[pos++];
657
658 if (len >= ce_namelen(p))
659 break;
660 if (memcmp(name, p->name, len))
661 break;
662 if (ce_stage(p) != stage)
663 continue;
664 if (p->name[len] != '/')
665 continue;
666 if (p->ce_flags & CE_REMOVE)
667 continue;
668 retval = -1;
669 if (!ok_to_replace)
670 break;
671 remove_index_entry_at(istate, --pos);
672 }
673 return retval;
674 }
675
676 /*
677 * Do we have another file with a pathname that is a proper
678 * subset of the name we're trying to add?
679 */
680 static int has_dir_name(struct index_state *istate,
681 const struct cache_entry *ce, int pos, int ok_to_replace)
682 {
683 int retval = 0;
684 int stage = ce_stage(ce);
685 const char *name = ce->name;
686 const char *slash = name + ce_namelen(ce);
687
688 for (;;) {
689 int len;
690
691 for (;;) {
692 if (*--slash == '/')
693 break;
694 if (slash <= ce->name)
695 return retval;
696 }
697 len = slash - name;
698
699 pos = index_name_pos(istate, name, create_ce_flags(len, stage));
700 if (pos >= 0) {
701 /*
702 * Found one, but not so fast. This could
703 * be a marker that says "I was here, but
704 * I am being removed". Such an entry is
705 * not a part of the resulting tree, and
706 * it is Ok to have a directory at the same
707 * path.
708 */
709 if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) {
710 retval = -1;
711 if (!ok_to_replace)
712 break;
713 remove_index_entry_at(istate, pos);
714 continue;
715 }
716 }
717 else
718 pos = -pos-1;
719
720 /*
721 * Trivial optimization: if we find an entry that
722 * already matches the sub-directory, then we know
723 * we're ok, and we can exit.
724 */
725 while (pos < istate->cache_nr) {
726 struct cache_entry *p = istate->cache[pos];
727 if ((ce_namelen(p) <= len) ||
728 (p->name[len] != '/') ||
729 memcmp(p->name, name, len))
730 break; /* not our subdirectory */
731 if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE))
732 /*
733 * p is at the same stage as our entry, and
734 * is a subdirectory of what we are looking
735 * at, so we cannot have conflicts at our
736 * level or anything shorter.
737 */
738 return retval;
739 pos++;
740 }
741 }
742 return retval;
743 }
744
745 /* We may be in a situation where we already have path/file and path
746 * is being added, or we already have path and path/file is being
747 * added. Either one would result in a nonsense tree that has path
748 * twice when git-write-tree tries to write it out. Prevent it.
749 *
750 * If ok-to-replace is specified, we remove the conflicting entries
751 * from the cache so the caller should recompute the insert position.
752 * When this happens, we return non-zero.
753 */
754 static int check_file_directory_conflict(struct index_state *istate,
755 const struct cache_entry *ce,
756 int pos, int ok_to_replace)
757 {
758 int retval;
759
760 /*
761 * When ce is an "I am going away" entry, we allow it to be added
762 */
763 if (ce->ce_flags & CE_REMOVE)
764 return 0;
765
766 /*
767 * We check if the path is a sub-path of a subsequent pathname
768 * first, since removing those will not change the position
769 * in the array.
770 */
771 retval = has_file_name(istate, ce, pos, ok_to_replace);
772
773 /*
774 * Then check if the path might have a clashing sub-directory
775 * before it.
776 */
777 return retval + has_dir_name(istate, ce, pos, ok_to_replace);
778 }
779
780 static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
781 {
782 int pos;
783 int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
784 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
785 int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
786
787 cache_tree_invalidate_path(istate->cache_tree, ce->name);
788 pos = index_name_pos(istate, ce->name, ce->ce_flags);
789
790 /* existing match? Just replace it. */
791 if (pos >= 0) {
792 replace_index_entry(istate, pos, ce);
793 return 0;
794 }
795 pos = -pos-1;
796
797 /*
798 * Inserting a merged entry ("stage 0") into the index
799 * will always replace all non-merged entries..
800 */
801 if (pos < istate->cache_nr && ce_stage(ce) == 0) {
802 while (ce_same_name(istate->cache[pos], ce)) {
803 ok_to_add = 1;
804 if (!remove_index_entry_at(istate, pos))
805 break;
806 }
807 }
808
809 if (!ok_to_add)
810 return -1;
811 if (!verify_path(ce->name))
812 return -1;
813
814 if (!skip_df_check &&
815 check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
816 if (!ok_to_replace)
817 return error("'%s' appears as both a file and as a directory",
818 ce->name);
819 pos = index_name_pos(istate, ce->name, ce->ce_flags);
820 pos = -pos-1;
821 }
822 return pos + 1;
823 }
824
825 int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
826 {
827 int pos;
828
829 if (option & ADD_CACHE_JUST_APPEND)
830 pos = istate->cache_nr;
831 else {
832 int ret;
833 ret = add_index_entry_with_check(istate, ce, option);
834 if (ret <= 0)
835 return ret;
836 pos = ret - 1;
837 }
838
839 /* Make sure the array is big enough .. */
840 if (istate->cache_nr == istate->cache_alloc) {
841 istate->cache_alloc = alloc_nr(istate->cache_alloc);
842 istate->cache = xrealloc(istate->cache,
843 istate->cache_alloc * sizeof(struct cache_entry *));
844 }
845
846 /* Add it in.. */
847 istate->cache_nr++;
848 if (istate->cache_nr > pos + 1)
849 memmove(istate->cache + pos + 1,
850 istate->cache + pos,
851 (istate->cache_nr - pos - 1) * sizeof(ce));
852 set_index_entry(istate, pos, ce);
853 istate->cache_changed = 1;
854 return 0;
855 }
856
857 /*
858 * "refresh" does not calculate a new sha1 file or bring the
859 * cache up-to-date for mode/content changes. But what it
860 * _does_ do is to "re-match" the stat information of a file
861 * with the cache, so that you can refresh the cache for a
862 * file that hasn't been changed but where the stat entry is
863 * out of date.
864 *
865 * For example, you'd want to do this after doing a "git-read-tree",
866 * to link up the stat cache details with the proper files.
867 */
868 static struct cache_entry *refresh_cache_ent(struct index_state *istate,
869 struct cache_entry *ce,
870 unsigned int options, int *err)
871 {
872 struct stat st;
873 struct cache_entry *updated;
874 int changed, size;
875 int ignore_valid = options & CE_MATCH_IGNORE_VALID;
876
877 if (ce_uptodate(ce))
878 return ce;
879
880 if (lstat(ce->name, &st) < 0) {
881 if (err)
882 *err = errno;
883 return NULL;
884 }
885
886 changed = ie_match_stat(istate, ce, &st, options);
887 if (!changed) {
888 /*
889 * The path is unchanged. If we were told to ignore
890 * valid bit, then we did the actual stat check and
891 * found that the entry is unmodified. If the entry
892 * is not marked VALID, this is the place to mark it
893 * valid again, under "assume unchanged" mode.
894 */
895 if (ignore_valid && assume_unchanged &&
896 !(ce->ce_flags & CE_VALID))
897 ; /* mark this one VALID again */
898 else {
899 /*
900 * We do not mark the index itself "modified"
901 * because CE_UPTODATE flag is in-core only;
902 * we are not going to write this change out.
903 */
904 ce_mark_uptodate(ce);
905 return ce;
906 }
907 }
908
909 if (ie_modified(istate, ce, &st, options)) {
910 if (err)
911 *err = EINVAL;
912 return NULL;
913 }
914
915 size = ce_size(ce);
916 updated = xmalloc(size);
917 memcpy(updated, ce, size);
918 fill_stat_cache_info(updated, &st);
919 /*
920 * If ignore_valid is not set, we should leave CE_VALID bit
921 * alone. Otherwise, paths marked with --no-assume-unchanged
922 * (i.e. things to be edited) will reacquire CE_VALID bit
923 * automatically, which is not really what we want.
924 */
925 if (!ignore_valid && assume_unchanged &&
926 !(ce->ce_flags & CE_VALID))
927 updated->ce_flags &= ~CE_VALID;
928
929 return updated;
930 }
931
932 int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
933 {
934 int i;
935 int has_errors = 0;
936 int really = (flags & REFRESH_REALLY) != 0;
937 int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
938 int quiet = (flags & REFRESH_QUIET) != 0;
939 int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
940 unsigned int options = really ? CE_MATCH_IGNORE_VALID : 0;
941
942 for (i = 0; i < istate->cache_nr; i++) {
943 struct cache_entry *ce, *new;
944 int cache_errno = 0;
945
946 ce = istate->cache[i];
947 if (ce_stage(ce)) {
948 while ((i < istate->cache_nr) &&
949 ! strcmp(istate->cache[i]->name, ce->name))
950 i++;
951 i--;
952 if (allow_unmerged)
953 continue;
954 printf("%s: needs merge\n", ce->name);
955 has_errors = 1;
956 continue;
957 }
958
959 if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
960 continue;
961
962 new = refresh_cache_ent(istate, ce, options, &cache_errno);
963 if (new == ce)
964 continue;
965 if (!new) {
966 if (not_new && cache_errno == ENOENT)
967 continue;
968 if (really && cache_errno == EINVAL) {
969 /* If we are doing --really-refresh that
970 * means the index is not valid anymore.
971 */
972 ce->ce_flags &= ~CE_VALID;
973 istate->cache_changed = 1;
974 }
975 if (quiet)
976 continue;
977 printf("%s: needs update\n", ce->name);
978 has_errors = 1;
979 continue;
980 }
981
982 replace_index_entry(istate, i, new);
983 }
984 return has_errors;
985 }
986
987 struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
988 {
989 return refresh_cache_ent(&the_index, ce, really, NULL);
990 }
991
992 static int verify_hdr(struct cache_header *hdr, unsigned long size)
993 {
994 SHA_CTX c;
995 unsigned char sha1[20];
996
997 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
998 return error("bad signature");
999 if (hdr->hdr_version != htonl(2))
1000 return error("bad index version");
1001 SHA1_Init(&c);
1002 SHA1_Update(&c, hdr, size - 20);
1003 SHA1_Final(sha1, &c);
1004 if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
1005 return error("bad index file sha1 signature");
1006 return 0;
1007 }
1008
1009 static int read_index_extension(struct index_state *istate,
1010 const char *ext, void *data, unsigned long sz)
1011 {
1012 switch (CACHE_EXT(ext)) {
1013 case CACHE_EXT_TREE:
1014 istate->cache_tree = cache_tree_read(data, sz);
1015 break;
1016 default:
1017 if (*ext < 'A' || 'Z' < *ext)
1018 return error("index uses %.4s extension, which we do not understand",
1019 ext);
1020 fprintf(stderr, "ignoring %.4s extension\n", ext);
1021 break;
1022 }
1023 return 0;
1024 }
1025
1026 int read_index(struct index_state *istate)
1027 {
1028 return read_index_from(istate, get_index_file());
1029 }
1030
1031 static void convert_from_disk(struct ondisk_cache_entry *ondisk, struct cache_entry *ce)
1032 {
1033 size_t len;
1034
1035 ce->ce_ctime = ntohl(ondisk->ctime.sec);
1036 ce->ce_mtime = ntohl(ondisk->mtime.sec);
1037 ce->ce_dev = ntohl(ondisk->dev);
1038 ce->ce_ino = ntohl(ondisk->ino);
1039 ce->ce_mode = ntohl(ondisk->mode);
1040 ce->ce_uid = ntohl(ondisk->uid);
1041 ce->ce_gid = ntohl(ondisk->gid);
1042 ce->ce_size = ntohl(ondisk->size);
1043 /* On-disk flags are just 16 bits */
1044 ce->ce_flags = ntohs(ondisk->flags);
1045 hashcpy(ce->sha1, ondisk->sha1);
1046
1047 len = ce->ce_flags & CE_NAMEMASK;
1048 if (len == CE_NAMEMASK)
1049 len = strlen(ondisk->name);
1050 /*
1051 * NEEDSWORK: If the original index is crafted, this copy could
1052 * go unchecked.
1053 */
1054 memcpy(ce->name, ondisk->name, len + 1);
1055 }
1056
1057 static inline size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
1058 {
1059 long per_entry;
1060
1061 per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
1062
1063 /*
1064 * Alignment can cause differences. This should be "alignof", but
1065 * since that's a gcc'ism, just use the size of a pointer.
1066 */
1067 per_entry += sizeof(void *);
1068 return ondisk_size + entries*per_entry;
1069 }
1070
1071 /* remember to discard_cache() before reading a different cache! */
1072 int read_index_from(struct index_state *istate, const char *path)
1073 {
1074 int fd, i;
1075 struct stat st;
1076 unsigned long src_offset, dst_offset;
1077 struct cache_header *hdr;
1078 void *mmap;
1079 size_t mmap_size;
1080
1081 errno = EBUSY;
1082 if (istate->alloc)
1083 return istate->cache_nr;
1084
1085 errno = ENOENT;
1086 istate->timestamp = 0;
1087 fd = open(path, O_RDONLY);
1088 if (fd < 0) {
1089 if (errno == ENOENT)
1090 return 0;
1091 die("index file open failed (%s)", strerror(errno));
1092 }
1093
1094 if (fstat(fd, &st))
1095 die("cannot stat the open index (%s)", strerror(errno));
1096
1097 errno = EINVAL;
1098 mmap_size = xsize_t(st.st_size);
1099 if (mmap_size < sizeof(struct cache_header) + 20)
1100 die("index file smaller than expected");
1101
1102 mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
1103 close(fd);
1104 if (mmap == MAP_FAILED)
1105 die("unable to map index file");
1106
1107 hdr = mmap;
1108 if (verify_hdr(hdr, mmap_size) < 0)
1109 goto unmap;
1110
1111 istate->cache_nr = ntohl(hdr->hdr_entries);
1112 istate->cache_alloc = alloc_nr(istate->cache_nr);
1113 istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
1114
1115 /*
1116 * The disk format is actually larger than the in-memory format,
1117 * due to space for nsec etc, so even though the in-memory one
1118 * has room for a few more flags, we can allocate using the same
1119 * index size
1120 */
1121 istate->alloc = xmalloc(estimate_cache_size(mmap_size, istate->cache_nr));
1122
1123 src_offset = sizeof(*hdr);
1124 dst_offset = 0;
1125 for (i = 0; i < istate->cache_nr; i++) {
1126 struct ondisk_cache_entry *disk_ce;
1127 struct cache_entry *ce;
1128
1129 disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
1130 ce = (struct cache_entry *)((char *)istate->alloc + dst_offset);
1131 convert_from_disk(disk_ce, ce);
1132 set_index_entry(istate, i, ce);
1133
1134 src_offset += ondisk_ce_size(ce);
1135 dst_offset += ce_size(ce);
1136 }
1137 istate->timestamp = st.st_mtime;
1138 while (src_offset <= mmap_size - 20 - 8) {
1139 /* After an array of active_nr index entries,
1140 * there can be arbitrary number of extended
1141 * sections, each of which is prefixed with
1142 * extension name (4-byte) and section length
1143 * in 4-byte network byte order.
1144 */
1145 unsigned long extsize;
1146 memcpy(&extsize, (char *)mmap + src_offset + 4, 4);
1147 extsize = ntohl(extsize);
1148 if (read_index_extension(istate,
1149 (const char *) mmap + src_offset,
1150 (char *) mmap + src_offset + 8,
1151 extsize) < 0)
1152 goto unmap;
1153 src_offset += 8;
1154 src_offset += extsize;
1155 }
1156 munmap(mmap, mmap_size);
1157 return istate->cache_nr;
1158
1159 unmap:
1160 munmap(mmap, mmap_size);
1161 errno = EINVAL;
1162 die("index file corrupt");
1163 }
1164
1165 int discard_index(struct index_state *istate)
1166 {
1167 istate->cache_nr = 0;
1168 istate->cache_changed = 0;
1169 istate->timestamp = 0;
1170 free_hash(&istate->name_hash);
1171 cache_tree_free(&(istate->cache_tree));
1172 free(istate->alloc);
1173 istate->alloc = NULL;
1174
1175 /* no need to throw away allocated active_cache */
1176 return 0;
1177 }
1178
1179 #define WRITE_BUFFER_SIZE 8192
1180 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
1181 static unsigned long write_buffer_len;
1182
1183 static int ce_write_flush(SHA_CTX *context, int fd)
1184 {
1185 unsigned int buffered = write_buffer_len;
1186 if (buffered) {
1187 SHA1_Update(context, write_buffer, buffered);
1188 if (write_in_full(fd, write_buffer, buffered) != buffered)
1189 return -1;
1190 write_buffer_len = 0;
1191 }
1192 return 0;
1193 }
1194
1195 static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
1196 {
1197 while (len) {
1198 unsigned int buffered = write_buffer_len;
1199 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1200 if (partial > len)
1201 partial = len;
1202 memcpy(write_buffer + buffered, data, partial);
1203 buffered += partial;
1204 if (buffered == WRITE_BUFFER_SIZE) {
1205 write_buffer_len = buffered;
1206 if (ce_write_flush(context, fd))
1207 return -1;
1208 buffered = 0;
1209 }
1210 write_buffer_len = buffered;
1211 len -= partial;
1212 data = (char *) data + partial;
1213 }
1214 return 0;
1215 }
1216
1217 static int write_index_ext_header(SHA_CTX *context, int fd,
1218 unsigned int ext, unsigned int sz)
1219 {
1220 ext = htonl(ext);
1221 sz = htonl(sz);
1222 return ((ce_write(context, fd, &ext, 4) < 0) ||
1223 (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1224 }
1225
1226 static int ce_flush(SHA_CTX *context, int fd)
1227 {
1228 unsigned int left = write_buffer_len;
1229
1230 if (left) {
1231 write_buffer_len = 0;
1232 SHA1_Update(context, write_buffer, left);
1233 }
1234
1235 /* Flush first if not enough space for SHA1 signature */
1236 if (left + 20 > WRITE_BUFFER_SIZE) {
1237 if (write_in_full(fd, write_buffer, left) != left)
1238 return -1;
1239 left = 0;
1240 }
1241
1242 /* Append the SHA1 signature at the end */
1243 SHA1_Final(write_buffer + left, context);
1244 left += 20;
1245 return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1246 }
1247
1248 static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1249 {
1250 /*
1251 * The only thing we care about in this function is to smudge the
1252 * falsely clean entry due to touch-update-touch race, so we leave
1253 * everything else as they are. We are called for entries whose
1254 * ce_mtime match the index file mtime.
1255 */
1256 struct stat st;
1257
1258 if (lstat(ce->name, &st) < 0)
1259 return;
1260 if (ce_match_stat_basic(ce, &st))
1261 return;
1262 if (ce_modified_check_fs(ce, &st)) {
1263 /* This is "racily clean"; smudge it. Note that this
1264 * is a tricky code. At first glance, it may appear
1265 * that it can break with this sequence:
1266 *
1267 * $ echo xyzzy >frotz
1268 * $ git-update-index --add frotz
1269 * $ : >frotz
1270 * $ sleep 3
1271 * $ echo filfre >nitfol
1272 * $ git-update-index --add nitfol
1273 *
1274 * but it does not. When the second update-index runs,
1275 * it notices that the entry "frotz" has the same timestamp
1276 * as index, and if we were to smudge it by resetting its
1277 * size to zero here, then the object name recorded
1278 * in index is the 6-byte file but the cached stat information
1279 * becomes zero --- which would then match what we would
1280 * obtain from the filesystem next time we stat("frotz").
1281 *
1282 * However, the second update-index, before calling
1283 * this function, notices that the cached size is 6
1284 * bytes and what is on the filesystem is an empty
1285 * file, and never calls us, so the cached size information
1286 * for "frotz" stays 6 which does not match the filesystem.
1287 */
1288 ce->ce_size = 0;
1289 }
1290 }
1291
1292 static int ce_write_entry(SHA_CTX *c, int fd, struct cache_entry *ce)
1293 {
1294 int size = ondisk_ce_size(ce);
1295 struct ondisk_cache_entry *ondisk = xcalloc(1, size);
1296
1297 ondisk->ctime.sec = htonl(ce->ce_ctime);
1298 ondisk->ctime.nsec = 0;
1299 ondisk->mtime.sec = htonl(ce->ce_mtime);
1300 ondisk->mtime.nsec = 0;
1301 ondisk->dev = htonl(ce->ce_dev);
1302 ondisk->ino = htonl(ce->ce_ino);
1303 ondisk->mode = htonl(ce->ce_mode);
1304 ondisk->uid = htonl(ce->ce_uid);
1305 ondisk->gid = htonl(ce->ce_gid);
1306 ondisk->size = htonl(ce->ce_size);
1307 hashcpy(ondisk->sha1, ce->sha1);
1308 ondisk->flags = htons(ce->ce_flags);
1309 memcpy(ondisk->name, ce->name, ce_namelen(ce));
1310
1311 return ce_write(c, fd, ondisk, size);
1312 }
1313
1314 int write_index(struct index_state *istate, int newfd)
1315 {
1316 SHA_CTX c;
1317 struct cache_header hdr;
1318 int i, err, removed;
1319 struct cache_entry **cache = istate->cache;
1320 int entries = istate->cache_nr;
1321
1322 for (i = removed = 0; i < entries; i++)
1323 if (cache[i]->ce_flags & CE_REMOVE)
1324 removed++;
1325
1326 hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1327 hdr.hdr_version = htonl(2);
1328 hdr.hdr_entries = htonl(entries - removed);
1329
1330 SHA1_Init(&c);
1331 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1332 return -1;
1333
1334 for (i = 0; i < entries; i++) {
1335 struct cache_entry *ce = cache[i];
1336 if (ce->ce_flags & CE_REMOVE)
1337 continue;
1338 if (is_racy_timestamp(istate, ce))
1339 ce_smudge_racily_clean_entry(ce);
1340 if (ce_write_entry(&c, newfd, ce) < 0)
1341 return -1;
1342 }
1343
1344 /* Write extension data here */
1345 if (istate->cache_tree) {
1346 struct strbuf sb;
1347
1348 strbuf_init(&sb, 0);
1349 cache_tree_write(&sb, istate->cache_tree);
1350 err = write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sb.len) < 0
1351 || ce_write(&c, newfd, sb.buf, sb.len) < 0;
1352 strbuf_release(&sb);
1353 if (err)
1354 return -1;
1355 }
1356 return ce_flush(&c, newfd);
1357 }