Merge branch 'rs/archive'
[git/builtin-gsoc.git] / read-cache.c
blob8b1c94e0e3f539cd0b507fd130b60aa443b9680b
1 /*
2 * GIT - The information manager from hell
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"
12 /* Index extensions.
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.
21 #define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
22 #define CACHE_EXT_TREE 0x54524545 /* "TREE" */
24 struct index_state the_index;
27 * This only updates the "non-critical" parts of the directory
28 * cache, ie the parts that aren't tracked by GIT, and only used
29 * to validate the cache.
31 void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
33 ce->ce_ctime.sec = htonl(st->st_ctime);
34 ce->ce_mtime.sec = htonl(st->st_mtime);
35 #ifdef USE_NSEC
36 ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
37 ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
38 #endif
39 ce->ce_dev = htonl(st->st_dev);
40 ce->ce_ino = htonl(st->st_ino);
41 ce->ce_uid = htonl(st->st_uid);
42 ce->ce_gid = htonl(st->st_gid);
43 ce->ce_size = htonl(st->st_size);
45 if (assume_unchanged)
46 ce->ce_flags |= htons(CE_VALID);
49 static int ce_compare_data(struct cache_entry *ce, struct stat *st)
51 int match = -1;
52 int fd = open(ce->name, O_RDONLY);
54 if (fd >= 0) {
55 unsigned char sha1[20];
56 if (!index_fd(sha1, fd, st, 0, OBJ_BLOB, ce->name))
57 match = hashcmp(sha1, ce->sha1);
58 /* index_fd() closed the file descriptor already */
60 return match;
63 static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
65 int match = -1;
66 char *target;
67 void *buffer;
68 unsigned long size;
69 enum object_type type;
70 int len;
72 target = xmalloc(expected_size);
73 len = readlink(ce->name, target, expected_size);
74 if (len != expected_size) {
75 free(target);
76 return -1;
78 buffer = read_sha1_file(ce->sha1, &type, &size);
79 if (!buffer) {
80 free(target);
81 return -1;
83 if (size == expected_size)
84 match = memcmp(buffer, target, size);
85 free(buffer);
86 free(target);
87 return match;
90 static int ce_compare_gitlink(struct cache_entry *ce)
92 unsigned char sha1[20];
95 * We don't actually require that the .git directory
96 * under GITLINK directory be a valid git directory. It
97 * might even be missing (in case nobody populated that
98 * sub-project).
100 * If so, we consider it always to match.
102 if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
103 return 0;
104 return hashcmp(sha1, ce->sha1);
107 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
109 switch (st->st_mode & S_IFMT) {
110 case S_IFREG:
111 if (ce_compare_data(ce, st))
112 return DATA_CHANGED;
113 break;
114 case S_IFLNK:
115 if (ce_compare_link(ce, xsize_t(st->st_size)))
116 return DATA_CHANGED;
117 break;
118 case S_IFDIR:
119 if (S_ISGITLINK(ntohl(ce->ce_mode)))
120 return 0;
121 default:
122 return TYPE_CHANGED;
124 return 0;
127 static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
129 unsigned int changed = 0;
131 switch (ntohl(ce->ce_mode) & S_IFMT) {
132 case S_IFREG:
133 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
134 /* We consider only the owner x bit to be relevant for
135 * "mode changes"
137 if (trust_executable_bit &&
138 (0100 & (ntohl(ce->ce_mode) ^ st->st_mode)))
139 changed |= MODE_CHANGED;
140 break;
141 case S_IFLNK:
142 if (!S_ISLNK(st->st_mode) &&
143 (has_symlinks || !S_ISREG(st->st_mode)))
144 changed |= TYPE_CHANGED;
145 break;
146 case S_IFGITLINK:
147 if (!S_ISDIR(st->st_mode))
148 changed |= TYPE_CHANGED;
149 else if (ce_compare_gitlink(ce))
150 changed |= DATA_CHANGED;
151 return changed;
152 default:
153 die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
155 if (ce->ce_mtime.sec != htonl(st->st_mtime))
156 changed |= MTIME_CHANGED;
157 if (ce->ce_ctime.sec != htonl(st->st_ctime))
158 changed |= CTIME_CHANGED;
160 #ifdef USE_NSEC
162 * nsec seems unreliable - not all filesystems support it, so
163 * as long as it is in the inode cache you get right nsec
164 * but after it gets flushed, you get zero nsec.
166 if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
167 changed |= MTIME_CHANGED;
168 if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
169 changed |= CTIME_CHANGED;
170 #endif
172 if (ce->ce_uid != htonl(st->st_uid) ||
173 ce->ce_gid != htonl(st->st_gid))
174 changed |= OWNER_CHANGED;
175 if (ce->ce_ino != htonl(st->st_ino))
176 changed |= INODE_CHANGED;
178 #ifdef USE_STDEV
180 * st_dev breaks on network filesystems where different
181 * clients will have different views of what "device"
182 * the filesystem is on
184 if (ce->ce_dev != htonl(st->st_dev))
185 changed |= INODE_CHANGED;
186 #endif
188 if (ce->ce_size != htonl(st->st_size))
189 changed |= DATA_CHANGED;
191 return changed;
194 int ie_match_stat(struct index_state *istate,
195 struct cache_entry *ce, struct stat *st, int options)
197 unsigned int changed;
198 int ignore_valid = options & 01;
199 int assume_racy_is_modified = options & 02;
202 * If it's marked as always valid in the index, it's
203 * valid whatever the checked-out copy says.
205 if (!ignore_valid && (ce->ce_flags & htons(CE_VALID)))
206 return 0;
208 changed = ce_match_stat_basic(ce, st);
211 * Within 1 second of this sequence:
212 * echo xyzzy >file && git-update-index --add file
213 * running this command:
214 * echo frotz >file
215 * would give a falsely clean cache entry. The mtime and
216 * length match the cache, and other stat fields do not change.
218 * We could detect this at update-index time (the cache entry
219 * being registered/updated records the same time as "now")
220 * and delay the return from git-update-index, but that would
221 * effectively mean we can make at most one commit per second,
222 * which is not acceptable. Instead, we check cache entries
223 * whose mtime are the same as the index file timestamp more
224 * carefully than others.
226 if (!changed &&
227 istate->timestamp &&
228 istate->timestamp <= ntohl(ce->ce_mtime.sec)) {
229 if (assume_racy_is_modified)
230 changed |= DATA_CHANGED;
231 else
232 changed |= ce_modified_check_fs(ce, st);
235 return changed;
238 int ie_modified(struct index_state *istate,
239 struct cache_entry *ce, struct stat *st, int really)
241 int changed, changed_fs;
242 changed = ie_match_stat(istate, ce, st, really);
243 if (!changed)
244 return 0;
246 * If the mode or type has changed, there's no point in trying
247 * to refresh the entry - it's not going to match
249 if (changed & (MODE_CHANGED | TYPE_CHANGED))
250 return changed;
252 /* Immediately after read-tree or update-index --cacheinfo,
253 * the length field is zero. For other cases the ce_size
254 * should match the SHA1 recorded in the index entry.
256 if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
257 return changed;
259 changed_fs = ce_modified_check_fs(ce, st);
260 if (changed_fs)
261 return changed | changed_fs;
262 return 0;
265 int base_name_compare(const char *name1, int len1, int mode1,
266 const char *name2, int len2, int mode2)
268 unsigned char c1, c2;
269 int len = len1 < len2 ? len1 : len2;
270 int cmp;
272 cmp = memcmp(name1, name2, len);
273 if (cmp)
274 return cmp;
275 c1 = name1[len];
276 c2 = name2[len];
277 if (!c1 && S_ISDIR(mode1))
278 c1 = '/';
279 if (!c2 && S_ISDIR(mode2))
280 c2 = '/';
281 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
284 int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
286 int len1 = flags1 & CE_NAMEMASK;
287 int len2 = flags2 & CE_NAMEMASK;
288 int len = len1 < len2 ? len1 : len2;
289 int cmp;
291 cmp = memcmp(name1, name2, len);
292 if (cmp)
293 return cmp;
294 if (len1 < len2)
295 return -1;
296 if (len1 > len2)
297 return 1;
299 /* Compare stages */
300 flags1 &= CE_STAGEMASK;
301 flags2 &= CE_STAGEMASK;
303 if (flags1 < flags2)
304 return -1;
305 if (flags1 > flags2)
306 return 1;
307 return 0;
310 int index_name_pos(struct index_state *istate, const char *name, int namelen)
312 int first, last;
314 first = 0;
315 last = istate->cache_nr;
316 while (last > first) {
317 int next = (last + first) >> 1;
318 struct cache_entry *ce = istate->cache[next];
319 int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
320 if (!cmp)
321 return next;
322 if (cmp < 0) {
323 last = next;
324 continue;
326 first = next+1;
328 return -first-1;
331 /* Remove entry, return true if there are more entries to go.. */
332 int remove_index_entry_at(struct index_state *istate, int pos)
334 istate->cache_changed = 1;
335 istate->cache_nr--;
336 if (pos >= istate->cache_nr)
337 return 0;
338 memmove(istate->cache + pos,
339 istate->cache + pos + 1,
340 (istate->cache_nr - pos) * sizeof(struct cache_entry *));
341 return 1;
344 int remove_file_from_index(struct index_state *istate, const char *path)
346 int pos = index_name_pos(istate, path, strlen(path));
347 if (pos < 0)
348 pos = -pos-1;
349 while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
350 remove_index_entry_at(istate, pos);
351 return 0;
354 static int compare_name(struct cache_entry *ce, const char *path, int namelen)
356 return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen);
359 static int index_name_pos_also_unmerged(struct index_state *istate,
360 const char *path, int namelen)
362 int pos = index_name_pos(istate, path, namelen);
363 struct cache_entry *ce;
365 if (pos >= 0)
366 return pos;
368 /* maybe unmerged? */
369 pos = -1 - pos;
370 if (pos >= istate->cache_nr ||
371 compare_name((ce = istate->cache[pos]), path, namelen))
372 return -1;
374 /* order of preference: stage 2, 1, 3 */
375 if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr &&
376 ce_stage((ce = istate->cache[pos + 1])) == 2 &&
377 !compare_name(ce, path, namelen))
378 pos++;
379 return pos;
382 int add_file_to_index(struct index_state *istate, const char *path, int verbose)
384 int size, namelen, pos;
385 struct stat st;
386 struct cache_entry *ce;
388 if (lstat(path, &st))
389 die("%s: unable to stat (%s)", path, strerror(errno));
391 if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
392 die("%s: can only add regular files, symbolic links or git-directories", path);
394 namelen = strlen(path);
395 if (S_ISDIR(st.st_mode)) {
396 while (namelen && path[namelen-1] == '/')
397 namelen--;
399 size = cache_entry_size(namelen);
400 ce = xcalloc(1, size);
401 memcpy(ce->name, path, namelen);
402 ce->ce_flags = htons(namelen);
403 fill_stat_cache_info(ce, &st);
405 if (trust_executable_bit && has_symlinks)
406 ce->ce_mode = create_ce_mode(st.st_mode);
407 else {
408 /* If there is an existing entry, pick the mode bits and type
409 * from it, otherwise assume unexecutable regular file.
411 struct cache_entry *ent;
412 int pos = index_name_pos_also_unmerged(istate, path, namelen);
414 ent = (0 <= pos) ? istate->cache[pos] : NULL;
415 ce->ce_mode = ce_mode_from_stat(ent, st.st_mode);
418 pos = index_name_pos(istate, ce->name, namelen);
419 if (0 <= pos &&
420 !ce_stage(istate->cache[pos]) &&
421 !ie_modified(istate, istate->cache[pos], &st, 1)) {
422 /* Nothing changed, really */
423 free(ce);
424 return 0;
427 if (index_path(ce->sha1, path, &st, 1))
428 die("unable to index file %s", path);
429 if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
430 die("unable to add %s to index",path);
431 if (verbose)
432 printf("add '%s'\n", path);
433 cache_tree_invalidate_path(istate->cache_tree, path);
434 return 0;
437 int ce_same_name(struct cache_entry *a, struct cache_entry *b)
439 int len = ce_namelen(a);
440 return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
443 int ce_path_match(const struct cache_entry *ce, const char **pathspec)
445 const char *match, *name;
446 int len;
448 if (!pathspec)
449 return 1;
451 len = ce_namelen(ce);
452 name = ce->name;
453 while ((match = *pathspec++) != NULL) {
454 int matchlen = strlen(match);
455 if (matchlen > len)
456 continue;
457 if (memcmp(name, match, matchlen))
458 continue;
459 if (matchlen && name[matchlen-1] == '/')
460 return 1;
461 if (name[matchlen] == '/' || !name[matchlen])
462 return 1;
463 if (!matchlen)
464 return 1;
466 return 0;
470 * We fundamentally don't like some paths: we don't want
471 * dot or dot-dot anywhere, and for obvious reasons don't
472 * want to recurse into ".git" either.
474 * Also, we don't want double slashes or slashes at the
475 * end that can make pathnames ambiguous.
477 static int verify_dotfile(const char *rest)
480 * The first character was '.', but that
481 * has already been discarded, we now test
482 * the rest.
484 switch (*rest) {
485 /* "." is not allowed */
486 case '\0': case '/':
487 return 0;
490 * ".git" followed by NUL or slash is bad. This
491 * shares the path end test with the ".." case.
493 case 'g':
494 if (rest[1] != 'i')
495 break;
496 if (rest[2] != 't')
497 break;
498 rest += 2;
499 /* fallthrough */
500 case '.':
501 if (rest[1] == '\0' || rest[1] == '/')
502 return 0;
504 return 1;
507 int verify_path(const char *path)
509 char c;
511 goto inside;
512 for (;;) {
513 if (!c)
514 return 1;
515 if (c == '/') {
516 inside:
517 c = *path++;
518 switch (c) {
519 default:
520 continue;
521 case '/': case '\0':
522 break;
523 case '.':
524 if (verify_dotfile(path))
525 continue;
527 return 0;
529 c = *path++;
534 * Do we have another file that has the beginning components being a
535 * proper superset of the name we're trying to add?
537 static int has_file_name(struct index_state *istate,
538 const struct cache_entry *ce, int pos, int ok_to_replace)
540 int retval = 0;
541 int len = ce_namelen(ce);
542 int stage = ce_stage(ce);
543 const char *name = ce->name;
545 while (pos < istate->cache_nr) {
546 struct cache_entry *p = istate->cache[pos++];
548 if (len >= ce_namelen(p))
549 break;
550 if (memcmp(name, p->name, len))
551 break;
552 if (ce_stage(p) != stage)
553 continue;
554 if (p->name[len] != '/')
555 continue;
556 if (!ce_stage(p) && !p->ce_mode)
557 continue;
558 retval = -1;
559 if (!ok_to_replace)
560 break;
561 remove_index_entry_at(istate, --pos);
563 return retval;
567 * Do we have another file with a pathname that is a proper
568 * subset of the name we're trying to add?
570 static int has_dir_name(struct index_state *istate,
571 const struct cache_entry *ce, int pos, int ok_to_replace)
573 int retval = 0;
574 int stage = ce_stage(ce);
575 const char *name = ce->name;
576 const char *slash = name + ce_namelen(ce);
578 for (;;) {
579 int len;
581 for (;;) {
582 if (*--slash == '/')
583 break;
584 if (slash <= ce->name)
585 return retval;
587 len = slash - name;
589 pos = index_name_pos(istate, name, ntohs(create_ce_flags(len, stage)));
590 if (pos >= 0) {
592 * Found one, but not so fast. This could
593 * be a marker that says "I was here, but
594 * I am being removed". Such an entry is
595 * not a part of the resulting tree, and
596 * it is Ok to have a directory at the same
597 * path.
599 if (stage || istate->cache[pos]->ce_mode) {
600 retval = -1;
601 if (!ok_to_replace)
602 break;
603 remove_index_entry_at(istate, pos);
604 continue;
607 else
608 pos = -pos-1;
611 * Trivial optimization: if we find an entry that
612 * already matches the sub-directory, then we know
613 * we're ok, and we can exit.
615 while (pos < istate->cache_nr) {
616 struct cache_entry *p = istate->cache[pos];
617 if ((ce_namelen(p) <= len) ||
618 (p->name[len] != '/') ||
619 memcmp(p->name, name, len))
620 break; /* not our subdirectory */
621 if (ce_stage(p) == stage && (stage || p->ce_mode))
622 /* p is at the same stage as our entry, and
623 * is a subdirectory of what we are looking
624 * at, so we cannot have conflicts at our
625 * level or anything shorter.
627 return retval;
628 pos++;
631 return retval;
634 /* We may be in a situation where we already have path/file and path
635 * is being added, or we already have path and path/file is being
636 * added. Either one would result in a nonsense tree that has path
637 * twice when git-write-tree tries to write it out. Prevent it.
639 * If ok-to-replace is specified, we remove the conflicting entries
640 * from the cache so the caller should recompute the insert position.
641 * When this happens, we return non-zero.
643 static int check_file_directory_conflict(struct index_state *istate,
644 const struct cache_entry *ce,
645 int pos, int ok_to_replace)
647 int retval;
650 * When ce is an "I am going away" entry, we allow it to be added
652 if (!ce_stage(ce) && !ce->ce_mode)
653 return 0;
656 * We check if the path is a sub-path of a subsequent pathname
657 * first, since removing those will not change the position
658 * in the array.
660 retval = has_file_name(istate, ce, pos, ok_to_replace);
663 * Then check if the path might have a clashing sub-directory
664 * before it.
666 return retval + has_dir_name(istate, ce, pos, ok_to_replace);
669 static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option)
671 int pos;
672 int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
673 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
674 int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
676 pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
678 /* existing match? Just replace it. */
679 if (pos >= 0) {
680 istate->cache_changed = 1;
681 istate->cache[pos] = ce;
682 return 0;
684 pos = -pos-1;
687 * Inserting a merged entry ("stage 0") into the index
688 * will always replace all non-merged entries..
690 if (pos < istate->cache_nr && ce_stage(ce) == 0) {
691 while (ce_same_name(istate->cache[pos], ce)) {
692 ok_to_add = 1;
693 if (!remove_index_entry_at(istate, pos))
694 break;
698 if (!ok_to_add)
699 return -1;
700 if (!verify_path(ce->name))
701 return -1;
703 if (!skip_df_check &&
704 check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
705 if (!ok_to_replace)
706 return error("'%s' appears as both a file and as a directory",
707 ce->name);
708 pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
709 pos = -pos-1;
711 return pos + 1;
714 int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
716 int pos;
718 if (option & ADD_CACHE_JUST_APPEND)
719 pos = istate->cache_nr;
720 else {
721 int ret;
722 ret = add_index_entry_with_check(istate, ce, option);
723 if (ret <= 0)
724 return ret;
725 pos = ret - 1;
728 /* Make sure the array is big enough .. */
729 if (istate->cache_nr == istate->cache_alloc) {
730 istate->cache_alloc = alloc_nr(istate->cache_alloc);
731 istate->cache = xrealloc(istate->cache,
732 istate->cache_alloc * sizeof(struct cache_entry *));
735 /* Add it in.. */
736 istate->cache_nr++;
737 if (istate->cache_nr > pos + 1)
738 memmove(istate->cache + pos + 1,
739 istate->cache + pos,
740 (istate->cache_nr - pos - 1) * sizeof(ce));
741 istate->cache[pos] = ce;
742 istate->cache_changed = 1;
743 return 0;
747 * "refresh" does not calculate a new sha1 file or bring the
748 * cache up-to-date for mode/content changes. But what it
749 * _does_ do is to "re-match" the stat information of a file
750 * with the cache, so that you can refresh the cache for a
751 * file that hasn't been changed but where the stat entry is
752 * out of date.
754 * For example, you'd want to do this after doing a "git-read-tree",
755 * to link up the stat cache details with the proper files.
757 static struct cache_entry *refresh_cache_ent(struct index_state *istate,
758 struct cache_entry *ce, int really, int *err)
760 struct stat st;
761 struct cache_entry *updated;
762 int changed, size;
764 if (lstat(ce->name, &st) < 0) {
765 if (err)
766 *err = errno;
767 return NULL;
770 changed = ie_match_stat(istate, ce, &st, really);
771 if (!changed) {
772 if (really && assume_unchanged &&
773 !(ce->ce_flags & htons(CE_VALID)))
774 ; /* mark this one VALID again */
775 else
776 return ce;
779 if (ie_modified(istate, ce, &st, really)) {
780 if (err)
781 *err = EINVAL;
782 return NULL;
785 size = ce_size(ce);
786 updated = xmalloc(size);
787 memcpy(updated, ce, size);
788 fill_stat_cache_info(updated, &st);
790 /* In this case, if really is not set, we should leave
791 * CE_VALID bit alone. Otherwise, paths marked with
792 * --no-assume-unchanged (i.e. things to be edited) will
793 * reacquire CE_VALID bit automatically, which is not
794 * really what we want.
796 if (!really && assume_unchanged && !(ce->ce_flags & htons(CE_VALID)))
797 updated->ce_flags &= ~htons(CE_VALID);
799 return updated;
802 int refresh_index(struct index_state *istate, unsigned int flags, const char **pathspec, char *seen)
804 int i;
805 int has_errors = 0;
806 int really = (flags & REFRESH_REALLY) != 0;
807 int allow_unmerged = (flags & REFRESH_UNMERGED) != 0;
808 int quiet = (flags & REFRESH_QUIET) != 0;
809 int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
811 for (i = 0; i < istate->cache_nr; i++) {
812 struct cache_entry *ce, *new;
813 int cache_errno = 0;
815 ce = istate->cache[i];
816 if (ce_stage(ce)) {
817 while ((i < istate->cache_nr) &&
818 ! strcmp(istate->cache[i]->name, ce->name))
819 i++;
820 i--;
821 if (allow_unmerged)
822 continue;
823 printf("%s: needs merge\n", ce->name);
824 has_errors = 1;
825 continue;
828 if (pathspec && !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
829 continue;
831 new = refresh_cache_ent(istate, ce, really, &cache_errno);
832 if (new == ce)
833 continue;
834 if (!new) {
835 if (not_new && cache_errno == ENOENT)
836 continue;
837 if (really && cache_errno == EINVAL) {
838 /* If we are doing --really-refresh that
839 * means the index is not valid anymore.
841 ce->ce_flags &= ~htons(CE_VALID);
842 istate->cache_changed = 1;
844 if (quiet)
845 continue;
846 printf("%s: needs update\n", ce->name);
847 has_errors = 1;
848 continue;
850 istate->cache_changed = 1;
851 /* You can NOT just free istate->cache[i] here, since it
852 * might not be necessarily malloc()ed but can also come
853 * from mmap(). */
854 istate->cache[i] = new;
856 return has_errors;
859 struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
861 return refresh_cache_ent(&the_index, ce, really, NULL);
864 static int verify_hdr(struct cache_header *hdr, unsigned long size)
866 SHA_CTX c;
867 unsigned char sha1[20];
869 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
870 return error("bad signature");
871 if (hdr->hdr_version != htonl(2))
872 return error("bad index version");
873 SHA1_Init(&c);
874 SHA1_Update(&c, hdr, size - 20);
875 SHA1_Final(sha1, &c);
876 if (hashcmp(sha1, (unsigned char *)hdr + size - 20))
877 return error("bad index file sha1 signature");
878 return 0;
881 static int read_index_extension(struct index_state *istate,
882 const char *ext, void *data, unsigned long sz)
884 switch (CACHE_EXT(ext)) {
885 case CACHE_EXT_TREE:
886 istate->cache_tree = cache_tree_read(data, sz);
887 break;
888 default:
889 if (*ext < 'A' || 'Z' < *ext)
890 return error("index uses %.4s extension, which we do not understand",
891 ext);
892 fprintf(stderr, "ignoring %.4s extension\n", ext);
893 break;
895 return 0;
898 int read_index(struct index_state *istate)
900 return read_index_from(istate, get_index_file());
903 /* remember to discard_cache() before reading a different cache! */
904 int read_index_from(struct index_state *istate, const char *path)
906 int fd, i;
907 struct stat st;
908 unsigned long offset;
909 struct cache_header *hdr;
911 errno = EBUSY;
912 if (istate->mmap)
913 return istate->cache_nr;
915 errno = ENOENT;
916 istate->timestamp = 0;
917 fd = open(path, O_RDONLY);
918 if (fd < 0) {
919 if (errno == ENOENT)
920 return 0;
921 die("index file open failed (%s)", strerror(errno));
924 if (fstat(fd, &st))
925 die("cannot stat the open index (%s)", strerror(errno));
927 errno = EINVAL;
928 istate->mmap_size = xsize_t(st.st_size);
929 if (istate->mmap_size < sizeof(struct cache_header) + 20)
930 die("index file smaller than expected");
932 istate->mmap = xmmap(NULL, istate->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
933 close(fd);
935 hdr = istate->mmap;
936 if (verify_hdr(hdr, istate->mmap_size) < 0)
937 goto unmap;
939 istate->cache_nr = ntohl(hdr->hdr_entries);
940 istate->cache_alloc = alloc_nr(istate->cache_nr);
941 istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
943 offset = sizeof(*hdr);
944 for (i = 0; i < istate->cache_nr; i++) {
945 struct cache_entry *ce;
947 ce = (struct cache_entry *)((char *)(istate->mmap) + offset);
948 offset = offset + ce_size(ce);
949 istate->cache[i] = ce;
951 istate->timestamp = st.st_mtime;
952 while (offset <= istate->mmap_size - 20 - 8) {
953 /* After an array of active_nr index entries,
954 * there can be arbitrary number of extended
955 * sections, each of which is prefixed with
956 * extension name (4-byte) and section length
957 * in 4-byte network byte order.
959 unsigned long extsize;
960 memcpy(&extsize, (char *)(istate->mmap) + offset + 4, 4);
961 extsize = ntohl(extsize);
962 if (read_index_extension(istate,
963 ((const char *) (istate->mmap)) + offset,
964 (char *) (istate->mmap) + offset + 8,
965 extsize) < 0)
966 goto unmap;
967 offset += 8;
968 offset += extsize;
970 return istate->cache_nr;
972 unmap:
973 munmap(istate->mmap, istate->mmap_size);
974 errno = EINVAL;
975 die("index file corrupt");
978 int discard_index(struct index_state *istate)
980 int ret;
982 istate->cache_nr = 0;
983 istate->cache_changed = 0;
984 istate->timestamp = 0;
985 cache_tree_free(&(istate->cache_tree));
986 if (istate->mmap == NULL)
987 return 0;
988 ret = munmap(istate->mmap, istate->mmap_size);
989 istate->mmap = NULL;
990 istate->mmap_size = 0;
992 /* no need to throw away allocated active_cache */
993 return ret;
996 #define WRITE_BUFFER_SIZE 8192
997 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
998 static unsigned long write_buffer_len;
1000 static int ce_write_flush(SHA_CTX *context, int fd)
1002 unsigned int buffered = write_buffer_len;
1003 if (buffered) {
1004 SHA1_Update(context, write_buffer, buffered);
1005 if (write_in_full(fd, write_buffer, buffered) != buffered)
1006 return -1;
1007 write_buffer_len = 0;
1009 return 0;
1012 static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
1014 while (len) {
1015 unsigned int buffered = write_buffer_len;
1016 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
1017 if (partial > len)
1018 partial = len;
1019 memcpy(write_buffer + buffered, data, partial);
1020 buffered += partial;
1021 if (buffered == WRITE_BUFFER_SIZE) {
1022 write_buffer_len = buffered;
1023 if (ce_write_flush(context, fd))
1024 return -1;
1025 buffered = 0;
1027 write_buffer_len = buffered;
1028 len -= partial;
1029 data = (char *) data + partial;
1031 return 0;
1034 static int write_index_ext_header(SHA_CTX *context, int fd,
1035 unsigned int ext, unsigned int sz)
1037 ext = htonl(ext);
1038 sz = htonl(sz);
1039 return ((ce_write(context, fd, &ext, 4) < 0) ||
1040 (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0;
1043 static int ce_flush(SHA_CTX *context, int fd)
1045 unsigned int left = write_buffer_len;
1047 if (left) {
1048 write_buffer_len = 0;
1049 SHA1_Update(context, write_buffer, left);
1052 /* Flush first if not enough space for SHA1 signature */
1053 if (left + 20 > WRITE_BUFFER_SIZE) {
1054 if (write_in_full(fd, write_buffer, left) != left)
1055 return -1;
1056 left = 0;
1059 /* Append the SHA1 signature at the end */
1060 SHA1_Final(write_buffer + left, context);
1061 left += 20;
1062 return (write_in_full(fd, write_buffer, left) != left) ? -1 : 0;
1065 static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
1068 * The only thing we care about in this function is to smudge the
1069 * falsely clean entry due to touch-update-touch race, so we leave
1070 * everything else as they are. We are called for entries whose
1071 * ce_mtime match the index file mtime.
1073 struct stat st;
1075 if (lstat(ce->name, &st) < 0)
1076 return;
1077 if (ce_match_stat_basic(ce, &st))
1078 return;
1079 if (ce_modified_check_fs(ce, &st)) {
1080 /* This is "racily clean"; smudge it. Note that this
1081 * is a tricky code. At first glance, it may appear
1082 * that it can break with this sequence:
1084 * $ echo xyzzy >frotz
1085 * $ git-update-index --add frotz
1086 * $ : >frotz
1087 * $ sleep 3
1088 * $ echo filfre >nitfol
1089 * $ git-update-index --add nitfol
1091 * but it does not. When the second update-index runs,
1092 * it notices that the entry "frotz" has the same timestamp
1093 * as index, and if we were to smudge it by resetting its
1094 * size to zero here, then the object name recorded
1095 * in index is the 6-byte file but the cached stat information
1096 * becomes zero --- which would then match what we would
1097 * obtain from the filesystem next time we stat("frotz").
1099 * However, the second update-index, before calling
1100 * this function, notices that the cached size is 6
1101 * bytes and what is on the filesystem is an empty
1102 * file, and never calls us, so the cached size information
1103 * for "frotz" stays 6 which does not match the filesystem.
1105 ce->ce_size = htonl(0);
1109 int write_index(struct index_state *istate, int newfd)
1111 SHA_CTX c;
1112 struct cache_header hdr;
1113 int i, removed;
1114 struct cache_entry **cache = istate->cache;
1115 int entries = istate->cache_nr;
1117 for (i = removed = 0; i < entries; i++)
1118 if (!cache[i]->ce_mode)
1119 removed++;
1121 hdr.hdr_signature = htonl(CACHE_SIGNATURE);
1122 hdr.hdr_version = htonl(2);
1123 hdr.hdr_entries = htonl(entries - removed);
1125 SHA1_Init(&c);
1126 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
1127 return -1;
1129 for (i = 0; i < entries; i++) {
1130 struct cache_entry *ce = cache[i];
1131 if (!ce->ce_mode)
1132 continue;
1133 if (istate->timestamp &&
1134 istate->timestamp <= ntohl(ce->ce_mtime.sec))
1135 ce_smudge_racily_clean_entry(ce);
1136 if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
1137 return -1;
1140 /* Write extension data here */
1141 if (istate->cache_tree) {
1142 unsigned long sz;
1143 void *data = cache_tree_write(istate->cache_tree, &sz);
1144 if (data &&
1145 !write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sz) &&
1146 !ce_write(&c, newfd, data, sz))
1147 free(data);
1148 else {
1149 free(data);
1150 return -1;
1153 return ce_flush(&c, newfd);