Improve config file escape sanity checking
[git/git.git] / read-cache.c
CommitLineData
8bc9a0c7
LT
1/*
2 * GIT - The information manager from hell
3 *
4 * Copyright (C) Linus Torvalds, 2005
5 */
e83c5163
LT
6#include "cache.h"
7
17712991 8int trust_executable_bit = 1;
e83c5163 9struct cache_entry **active_cache = NULL;
ee267527 10unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
e83c5163 11
415e96c8
JH
12/*
13 * This only updates the "non-critical" parts of the directory
14 * cache, ie the parts that aren't tracked by GIT, and only used
15 * to validate the cache.
16 */
17void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
18{
19 ce->ce_ctime.sec = htonl(st->st_ctime);
20 ce->ce_mtime.sec = htonl(st->st_mtime);
2cb45e95 21#ifdef USE_NSEC
415e96c8
JH
22 ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
23 ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
24#endif
25 ce->ce_dev = htonl(st->st_dev);
26 ce->ce_ino = htonl(st->st_ino);
27 ce->ce_uid = htonl(st->st_uid);
28 ce->ce_gid = htonl(st->st_gid);
29 ce->ce_size = htonl(st->st_size);
30}
31
5d728c84 32int ce_match_stat(struct cache_entry *ce, struct stat *st)
734aab75
LT
33{
34 unsigned int changed = 0;
35
8ae0a8c5
KS
36 switch (ntohl(ce->ce_mode) & S_IFMT) {
37 case S_IFREG:
38 changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
ffbe1add
KS
39 /* We consider only the owner x bit to be relevant for "mode changes" */
40 if (0100 & (ntohl(ce->ce_mode) ^ st->st_mode))
41 changed |= MODE_CHANGED;
8ae0a8c5
KS
42 break;
43 case S_IFLNK:
44 changed |= !S_ISLNK(st->st_mode) ? TYPE_CHANGED : 0;
45 break;
46 default:
47 die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
48 }
ccc4feb5 49 if (ce->ce_mtime.sec != htonl(st->st_mtime))
734aab75 50 changed |= MTIME_CHANGED;
ccc4feb5
LT
51 if (ce->ce_ctime.sec != htonl(st->st_ctime))
52 changed |= CTIME_CHANGED;
53
2cb45e95 54#ifdef USE_NSEC
ccc4feb5
LT
55 /*
56 * nsec seems unreliable - not all filesystems support it, so
57 * as long as it is in the inode cache you get right nsec
58 * but after it gets flushed, you get zero nsec.
59 */
94dfb7f2 60 if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
ccc4feb5 61 changed |= MTIME_CHANGED;
94dfb7f2 62 if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
734aab75 63 changed |= CTIME_CHANGED;
ccc4feb5
LT
64#endif
65
66 if (ce->ce_uid != htonl(st->st_uid) ||
67 ce->ce_gid != htonl(st->st_gid))
734aab75 68 changed |= OWNER_CHANGED;
2cb45e95 69 if (ce->ce_ino != htonl(st->st_ino))
734aab75 70 changed |= INODE_CHANGED;
2cb45e95
LT
71
72#ifdef USE_STDEV
73 /*
74 * st_dev breaks on network filesystems where different
75 * clients will have different views of what "device"
76 * the filesystem is on
77 */
78 if (ce->ce_dev != htonl(st->st_dev))
79 changed |= INODE_CHANGED;
80#endif
81
ccc4feb5 82 if (ce->ce_size != htonl(st->st_size))
734aab75
LT
83 changed |= DATA_CHANGED;
84 return changed;
85}
86
b0391890
JH
87static int ce_compare_data(struct cache_entry *ce, struct stat *st)
88{
89 int match = -1;
90 int fd = open(ce->name, O_RDONLY);
91
92 if (fd >= 0) {
93 unsigned char sha1[20];
94 if (!index_fd(sha1, fd, st, 0, NULL))
95 match = memcmp(sha1, ce->sha1, 20);
96 close(fd);
97 }
98 return match;
99}
100
101static int ce_compare_link(struct cache_entry *ce, unsigned long expected_size)
102{
103 int match = -1;
104 char *target;
105 void *buffer;
106 unsigned long size;
107 char type[10];
108 int len;
109
110 target = xmalloc(expected_size);
111 len = readlink(ce->name, target, expected_size);
112 if (len != expected_size) {
113 free(target);
114 return -1;
115 }
116 buffer = read_sha1_file(ce->sha1, type, &size);
117 if (!buffer) {
118 free(target);
119 return -1;
120 }
121 if (size == expected_size)
122 match = memcmp(buffer, target, size);
123 free(buffer);
124 free(target);
125 return match;
126}
127
128int ce_modified(struct cache_entry *ce, struct stat *st)
129{
130 int changed;
131 changed = ce_match_stat(ce, st);
132 if (!changed)
133 return 0;
134
135 /*
136 * If the mode or type has changed, there's no point in trying
137 * to refresh the entry - it's not going to match
138 */
139 if (changed & (MODE_CHANGED | TYPE_CHANGED))
140 return changed;
141
142 /* Immediately after read-tree or update-index --cacheinfo,
143 * the length field is zero. For other cases the ce_size
144 * should match the SHA1 recorded in the index entry.
145 */
146 if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
147 return changed;
148
149 switch (st->st_mode & S_IFMT) {
150 case S_IFREG:
151 if (ce_compare_data(ce, st))
152 return changed | DATA_CHANGED;
153 break;
154 case S_IFLNK:
155 if (ce_compare_link(ce, st->st_size))
156 return changed | DATA_CHANGED;
157 break;
158 default:
159 return changed | TYPE_CHANGED;
160 }
161 return 0;
162}
163
958ba6c9
LT
164int base_name_compare(const char *name1, int len1, int mode1,
165 const char *name2, int len2, int mode2)
166{
167 unsigned char c1, c2;
168 int len = len1 < len2 ? len1 : len2;
169 int cmp;
170
171 cmp = memcmp(name1, name2, len);
172 if (cmp)
173 return cmp;
174 c1 = name1[len];
175 c2 = name2[len];
176 if (!c1 && S_ISDIR(mode1))
177 c1 = '/';
178 if (!c2 && S_ISDIR(mode2))
179 c2 = '/';
180 return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
181}
182
95fd5bf8 183int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
eb38c22f 184{
95fd5bf8
LT
185 int len1 = flags1 & CE_NAMEMASK;
186 int len2 = flags2 & CE_NAMEMASK;
eb38c22f
LT
187 int len = len1 < len2 ? len1 : len2;
188 int cmp;
189
190 cmp = memcmp(name1, name2, len);
191 if (cmp)
192 return cmp;
193 if (len1 < len2)
194 return -1;
195 if (len1 > len2)
196 return 1;
95fd5bf8
LT
197 if (flags1 < flags2)
198 return -1;
199 if (flags1 > flags2)
200 return 1;
eb38c22f
LT
201 return 0;
202}
203
204int cache_name_pos(const char *name, int namelen)
205{
206 int first, last;
207
208 first = 0;
209 last = active_nr;
210 while (last > first) {
211 int next = (last + first) >> 1;
212 struct cache_entry *ce = active_cache[next];
972d1bb0 213 int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
eb38c22f 214 if (!cmp)
76e7f4ec 215 return next;
eb38c22f
LT
216 if (cmp < 0) {
217 last = next;
218 continue;
219 }
220 first = next+1;
221 }
76e7f4ec 222 return -first-1;
eb38c22f
LT
223}
224
7b937ca3 225/* Remove entry, return true if there are more entries to go.. */
dbbce55b 226int remove_cache_entry_at(int pos)
7b937ca3 227{
ee267527 228 active_cache_changed = 1;
7b937ca3
LT
229 active_nr--;
230 if (pos >= active_nr)
231 return 0;
232 memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
233 return 1;
234}
235
6b5ee137 236int remove_file_from_cache(const char *path)
197ee8c9
LT
237{
238 int pos = cache_name_pos(path, strlen(path));
c4e3cca1
JH
239 if (pos < 0)
240 pos = -pos-1;
241 while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
dbbce55b 242 remove_cache_entry_at(pos);
197ee8c9
LT
243 return 0;
244}
245
dbbce55b 246int ce_same_name(struct cache_entry *a, struct cache_entry *b)
7b937ca3
LT
247{
248 int len = ce_namelen(a);
249 return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
250}
251
c0fd1f51
LT
252int ce_path_match(const struct cache_entry *ce, const char **pathspec)
253{
254 const char *match, *name;
255 int len;
256
257 if (!pathspec)
258 return 1;
259
260 len = ce_namelen(ce);
261 name = ce->name;
262 while ((match = *pathspec++) != NULL) {
263 int matchlen = strlen(match);
264 if (matchlen > len)
265 continue;
266 if (memcmp(name, match, matchlen))
267 continue;
268 if (matchlen && name[matchlen-1] == '/')
269 return 1;
270 if (name[matchlen] == '/' || !name[matchlen])
271 return 1;
f332726e
LT
272 if (!matchlen)
273 return 1;
c0fd1f51
LT
274 }
275 return 0;
276}
277
12676608
LT
278/*
279 * Do we have another file that has the beginning components being a
280 * proper superset of the name we're trying to add?
0f1e4f04 281 */
12676608 282static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
0f1e4f04 283{
12676608
LT
284 int retval = 0;
285 int len = ce_namelen(ce);
b155725d 286 int stage = ce_stage(ce);
12676608 287 const char *name = ce->name;
0f1e4f04 288
12676608
LT
289 while (pos < active_nr) {
290 struct cache_entry *p = active_cache[pos++];
0f1e4f04 291
12676608 292 if (len >= ce_namelen(p))
0f1e4f04 293 break;
12676608
LT
294 if (memcmp(name, p->name, len))
295 break;
b155725d
JH
296 if (ce_stage(p) != stage)
297 continue;
12676608
LT
298 if (p->name[len] != '/')
299 continue;
12676608
LT
300 retval = -1;
301 if (!ok_to_replace)
302 break;
303 remove_cache_entry_at(--pos);
0f1e4f04 304 }
12676608
LT
305 return retval;
306}
0f1e4f04 307
12676608
LT
308/*
309 * Do we have another file with a pathname that is a proper
310 * subset of the name we're trying to add?
311 */
312static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
313{
314 int retval = 0;
b155725d 315 int stage = ce_stage(ce);
12676608
LT
316 const char *name = ce->name;
317 const char *slash = name + ce_namelen(ce);
0f1e4f04 318
12676608
LT
319 for (;;) {
320 int len;
0f1e4f04 321
12676608
LT
322 for (;;) {
323 if (*--slash == '/')
324 break;
325 if (slash <= ce->name)
326 return retval;
327 }
328 len = slash - name;
0f1e4f04 329
b155725d 330 pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
12676608
LT
331 if (pos >= 0) {
332 retval = -1;
333 if (ok_to_replace)
334 break;
dbbce55b 335 remove_cache_entry_at(pos);
12676608
LT
336 continue;
337 }
338
339 /*
340 * Trivial optimization: if we find an entry that
341 * already matches the sub-directory, then we know
b155725d 342 * we're ok, and we can exit.
12676608
LT
343 */
344 pos = -pos-1;
b155725d 345 while (pos < active_nr) {
12676608 346 struct cache_entry *p = active_cache[pos];
b155725d
JH
347 if ((ce_namelen(p) <= len) ||
348 (p->name[len] != '/') ||
349 memcmp(p->name, name, len))
350 break; /* not our subdirectory */
351 if (ce_stage(p) == stage)
352 /* p is at the same stage as our entry, and
353 * is a subdirectory of what we are looking
354 * at, so we cannot have conflicts at our
355 * level or anything shorter.
356 */
357 return retval;
358 pos++;
192268c1 359 }
0f1e4f04 360 }
12676608
LT
361 return retval;
362}
363
364/* We may be in a situation where we already have path/file and path
365 * is being added, or we already have path and path/file is being
366 * added. Either one would result in a nonsense tree that has path
367 * twice when git-write-tree tries to write it out. Prevent it.
368 *
369 * If ok-to-replace is specified, we remove the conflicting entries
370 * from the cache so the caller should recompute the insert position.
371 * When this happens, we return non-zero.
372 */
373static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
374{
375 /*
376 * We check if the path is a sub-path of a subsequent pathname
377 * first, since removing those will not change the position
378 * in the array
379 */
380 int retval = has_file_name(ce, pos, ok_to_replace);
381 /*
382 * Then check if the path might have a clashing sub-directory
383 * before it.
384 */
385 return retval + has_dir_name(ce, pos, ok_to_replace);
0f1e4f04
JH
386}
387
192268c1 388int add_cache_entry(struct cache_entry *ce, int option)
197ee8c9
LT
389{
390 int pos;
192268c1
JH
391 int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
392 int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
b155725d 393 int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
972d1bb0 394 pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
197ee8c9
LT
395
396 /* existing match? Just replace it */
76e7f4ec 397 if (pos >= 0) {
ee267527 398 active_cache_changed = 1;
76e7f4ec 399 active_cache[pos] = ce;
197ee8c9
LT
400 return 0;
401 }
76e7f4ec 402 pos = -pos-1;
197ee8c9 403
7b937ca3
LT
404 /*
405 * Inserting a merged entry ("stage 0") into the index
406 * will always replace all non-merged entries..
407 */
408 if (pos < active_nr && ce_stage(ce) == 0) {
dbbce55b 409 while (ce_same_name(active_cache[pos], ce)) {
7b937ca3 410 ok_to_add = 1;
dbbce55b 411 if (!remove_cache_entry_at(pos))
7b937ca3
LT
412 break;
413 }
414 }
415
121481ab
LT
416 if (!ok_to_add)
417 return -1;
418
b155725d 419 if (!skip_df_check && check_file_directory_conflict(ce, pos, ok_to_replace)) {
192268c1
JH
420 if (!ok_to_replace)
421 return -1;
972d1bb0 422 pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
192268c1
JH
423 pos = -pos-1;
424 }
0f1e4f04 425
197ee8c9
LT
426 /* Make sure the array is big enough .. */
427 if (active_nr == active_alloc) {
428 active_alloc = alloc_nr(active_alloc);
812666c8 429 active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
197ee8c9
LT
430 }
431
432 /* Add it in.. */
433 active_nr++;
434 if (active_nr > pos)
435 memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
436 active_cache[pos] = ce;
ee267527 437 active_cache_changed = 1;
197ee8c9
LT
438 return 0;
439}
440
e83c5163
LT
441static int verify_hdr(struct cache_header *hdr, unsigned long size)
442{
443 SHA_CTX c;
444 unsigned char sha1[20];
445
ccc4feb5 446 if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
e83c5163 447 return error("bad signature");
ca9be054
LT
448 if (hdr->hdr_version != htonl(2))
449 return error("bad index version");
e83c5163 450 SHA1_Init(&c);
ca9be054 451 SHA1_Update(&c, hdr, size - 20);
e83c5163 452 SHA1_Final(sha1, &c);
ca9be054
LT
453 if (memcmp(sha1, (void *)hdr + size - 20, 20))
454 return error("bad index file sha1 signature");
e83c5163
LT
455 return 0;
456}
457
458int read_cache(void)
459{
460 int fd, i;
461 struct stat st;
462 unsigned long size, offset;
463 void *map;
464 struct cache_header *hdr;
465
466 errno = EBUSY;
467 if (active_cache)
5d1a5c02
LT
468 return active_nr;
469
e83c5163 470 errno = ENOENT;
bb233d69 471 fd = open(get_index_file(), O_RDONLY);
5d1a5c02
LT
472 if (fd < 0) {
473 if (errno == ENOENT)
474 return 0;
475 die("index file open failed (%s)", strerror(errno));
476 }
e83c5163 477
19b2860c 478 size = 0; // avoid gcc warning
e35f9824 479 map = MAP_FAILED;
e83c5163 480 if (!fstat(fd, &st)) {
e83c5163
LT
481 size = st.st_size;
482 errno = EINVAL;
ca9be054 483 if (size >= sizeof(struct cache_header) + 20)
520fc241 484 map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
e83c5163
LT
485 }
486 close(fd);
e35f9824 487 if (map == MAP_FAILED)
5d1a5c02 488 die("index file mmap failed (%s)", strerror(errno));
e83c5163
LT
489
490 hdr = map;
491 if (verify_hdr(hdr, size) < 0)
492 goto unmap;
493
ccc4feb5 494 active_nr = ntohl(hdr->hdr_entries);
e83c5163
LT
495 active_alloc = alloc_nr(active_nr);
496 active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
497
498 offset = sizeof(*hdr);
ccc4feb5 499 for (i = 0; i < active_nr; i++) {
e83c5163
LT
500 struct cache_entry *ce = map + offset;
501 offset = offset + ce_size(ce);
502 active_cache[i] = ce;
503 }
504 return active_nr;
505
506unmap:
507 munmap(map, size);
508 errno = EINVAL;
5d1a5c02 509 die("index file corrupt");
e83c5163
LT
510}
511
4990aadc 512#define WRITE_BUFFER_SIZE 8192
bf0f910d 513static unsigned char write_buffer[WRITE_BUFFER_SIZE];
4990aadc
LT
514static unsigned long write_buffer_len;
515
ca9be054 516static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
4990aadc
LT
517{
518 while (len) {
519 unsigned int buffered = write_buffer_len;
520 unsigned int partial = WRITE_BUFFER_SIZE - buffered;
521 if (partial > len)
522 partial = len;
523 memcpy(write_buffer + buffered, data, partial);
524 buffered += partial;
525 if (buffered == WRITE_BUFFER_SIZE) {
ca9be054 526 SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
4990aadc
LT
527 if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
528 return -1;
529 buffered = 0;
530 }
531 write_buffer_len = buffered;
532 len -= partial;
533 data += partial;
534 }
535 return 0;
536}
537
ca9be054 538static int ce_flush(SHA_CTX *context, int fd)
4990aadc
LT
539{
540 unsigned int left = write_buffer_len;
ca9be054 541
4990aadc
LT
542 if (left) {
543 write_buffer_len = 0;
ca9be054 544 SHA1_Update(context, write_buffer, left);
4990aadc 545 }
ca9be054 546
2c865d9a
QH
547 /* Flush first if not enough space for SHA1 signature */
548 if (left + 20 > WRITE_BUFFER_SIZE) {
549 if (write(fd, write_buffer, left) != left)
550 return -1;
551 left = 0;
552 }
553
ca9be054
LT
554 /* Append the SHA1 signature at the end */
555 SHA1_Final(write_buffer + left, context);
556 left += 20;
557 if (write(fd, write_buffer, left) != left)
558 return -1;
4990aadc
LT
559 return 0;
560}
561
197ee8c9
LT
562int write_cache(int newfd, struct cache_entry **cache, int entries)
563{
564 SHA_CTX c;
565 struct cache_header hdr;
025a0709
JH
566 int i, removed;
567
568 for (i = removed = 0; i < entries; i++)
569 if (!cache[i]->ce_mode)
570 removed++;
197ee8c9 571
ccc4feb5 572 hdr.hdr_signature = htonl(CACHE_SIGNATURE);
ca9be054 573 hdr.hdr_version = htonl(2);
025a0709 574 hdr.hdr_entries = htonl(entries - removed);
197ee8c9
LT
575
576 SHA1_Init(&c);
ca9be054 577 if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
197ee8c9
LT
578 return -1;
579
580 for (i = 0; i < entries; i++) {
581 struct cache_entry *ce = cache[i];
aa16021e
LT
582 if (!ce->ce_mode)
583 continue;
ca9be054 584 if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
197ee8c9
LT
585 return -1;
586 }
ca9be054 587 return ce_flush(&c, newfd);
197ee8c9 588}