1 /*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
21 */
22
23 /*
24 * This header contains various key-related definitions and helper function.
25 * UBIFS allows several key schemes, so we access key fields only via these
26 * helpers. At the moment only one key scheme is supported.
27 *
28 * Simple key scheme
29 * ~~~~~~~~~~~~~~~~~
30 *
31 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
32 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
33 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
34 * node. We use "r5" hash borrowed from reiserfs.
35 */
36
37 #ifndef __UBIFS_KEY_H__
38 #define __UBIFS_KEY_H__
39
40 /**
41 * key_mask_hash - mask a valid hash value.
42 * @val: value to be masked
43 *
44 * We use hash values as offset in directories, so values %0 and %1 are
45 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
46 * function makes sure the reserved values are not used.
47 */
key_mask_hash(uint32_t hash)48 static inline uint32_t key_mask_hash(uint32_t hash)
49 {
50 hash &= UBIFS_S_KEY_HASH_MASK;
51 if (unlikely(hash <= 2))
52 hash += 3;
53 return hash;
54 }
55
56 /**
57 * key_r5_hash - R5 hash function (borrowed from reiserfs).
58 * @s: direntry name
59 * @len: name length
60 */
key_r5_hash(const char * s,int len)61 static inline uint32_t key_r5_hash(const char *s, int len)
62 {
63 uint32_t a = 0;
64 const signed char *str = (const signed char *)s;
65
66 while (*str) {
67 a += *str << 4;
68 a += *str >> 4;
69 a *= 11;
70 str++;
71 }
72
73 return key_mask_hash(a);
74 }
75
76 /**
77 * key_test_hash - testing hash function.
78 * @str: direntry name
79 * @len: name length
80 */
key_test_hash(const char * str,int len)81 static inline uint32_t key_test_hash(const char *str, int len)
82 {
83 uint32_t a = 0;
84
85 len = min_t(uint32_t, len, 4);
86 memcpy(&a, str, len);
87 return key_mask_hash(a);
88 }
89
90 /**
91 * ino_key_init - initialize inode key.
92 * @c: UBIFS file-system description object
93 * @key: key to initialize
94 * @inum: inode number
95 */
ino_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)96 static inline void ino_key_init(const struct ubifs_info *c,
97 union ubifs_key *key, ino_t inum)
98 {
99 key->u32[0] = inum;
100 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
101 }
102
103 /**
104 * ino_key_init_flash - initialize on-flash inode key.
105 * @c: UBIFS file-system description object
106 * @k: key to initialize
107 * @inum: inode number
108 */
ino_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum)109 static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
110 ino_t inum)
111 {
112 union ubifs_key *key = k;
113
114 key->j32[0] = cpu_to_le32(inum);
115 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
116 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
117 }
118
119 /**
120 * lowest_ino_key - get the lowest possible inode key.
121 * @c: UBIFS file-system description object
122 * @key: key to initialize
123 * @inum: inode number
124 */
lowest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)125 static inline void lowest_ino_key(const struct ubifs_info *c,
126 union ubifs_key *key, ino_t inum)
127 {
128 key->u32[0] = inum;
129 key->u32[1] = 0;
130 }
131
132 /**
133 * highest_ino_key - get the highest possible inode key.
134 * @c: UBIFS file-system description object
135 * @key: key to initialize
136 * @inum: inode number
137 */
highest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)138 static inline void highest_ino_key(const struct ubifs_info *c,
139 union ubifs_key *key, ino_t inum)
140 {
141 key->u32[0] = inum;
142 key->u32[1] = 0xffffffff;
143 }
144
145 /**
146 * dent_key_init - initialize directory entry key.
147 * @c: UBIFS file-system description object
148 * @key: key to initialize
149 * @inum: parent inode number
150 * @nm: direntry name and length
151 */
dent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)152 static inline void dent_key_init(const struct ubifs_info *c,
153 union ubifs_key *key, ino_t inum,
154 const struct qstr *nm)
155 {
156 uint32_t hash = c->key_hash(nm->name, nm->len);
157
158 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
159 key->u32[0] = inum;
160 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
161 }
162
163 /**
164 * dent_key_init_hash - initialize directory entry key without re-calculating
165 * hash function.
166 * @c: UBIFS file-system description object
167 * @key: key to initialize
168 * @inum: parent inode number
169 * @hash: direntry name hash
170 */
dent_key_init_hash(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,uint32_t hash)171 static inline void dent_key_init_hash(const struct ubifs_info *c,
172 union ubifs_key *key, ino_t inum,
173 uint32_t hash)
174 {
175 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
176 key->u32[0] = inum;
177 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
178 }
179
180 /**
181 * dent_key_init_flash - initialize on-flash directory entry key.
182 * @c: UBIFS file-system description object
183 * @k: key to initialize
184 * @inum: parent inode number
185 * @nm: direntry name and length
186 */
dent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)187 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
188 ino_t inum, const struct qstr *nm)
189 {
190 union ubifs_key *key = k;
191 uint32_t hash = c->key_hash(nm->name, nm->len);
192
193 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
194 key->j32[0] = cpu_to_le32(inum);
195 key->j32[1] = cpu_to_le32(hash |
196 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
197 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
198 }
199
200 /**
201 * lowest_dent_key - get the lowest possible directory entry key.
202 * @c: UBIFS file-system description object
203 * @key: where to store the lowest key
204 * @inum: parent inode number
205 */
lowest_dent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)206 static inline void lowest_dent_key(const struct ubifs_info *c,
207 union ubifs_key *key, ino_t inum)
208 {
209 key->u32[0] = inum;
210 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
211 }
212
213 /**
214 * xent_key_init - initialize extended attribute entry key.
215 * @c: UBIFS file-system description object
216 * @key: key to initialize
217 * @inum: host inode number
218 * @nm: extended attribute entry name and length
219 */
xent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)220 static inline void xent_key_init(const struct ubifs_info *c,
221 union ubifs_key *key, ino_t inum,
222 const struct qstr *nm)
223 {
224 uint32_t hash = c->key_hash(nm->name, nm->len);
225
226 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
227 key->u32[0] = inum;
228 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
229 }
230
231 /**
232 * xent_key_init_flash - initialize on-flash extended attribute entry key.
233 * @c: UBIFS file-system description object
234 * @k: key to initialize
235 * @inum: host inode number
236 * @nm: extended attribute entry name and length
237 */
xent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)238 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
239 ino_t inum, const struct qstr *nm)
240 {
241 union ubifs_key *key = k;
242 uint32_t hash = c->key_hash(nm->name, nm->len);
243
244 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
245 key->j32[0] = cpu_to_le32(inum);
246 key->j32[1] = cpu_to_le32(hash |
247 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
248 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
249 }
250
251 /**
252 * lowest_xent_key - get the lowest possible extended attribute entry key.
253 * @c: UBIFS file-system description object
254 * @key: where to store the lowest key
255 * @inum: host inode number
256 */
lowest_xent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)257 static inline void lowest_xent_key(const struct ubifs_info *c,
258 union ubifs_key *key, ino_t inum)
259 {
260 key->u32[0] = inum;
261 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
262 }
263
264 /**
265 * data_key_init - initialize data key.
266 * @c: UBIFS file-system description object
267 * @key: key to initialize
268 * @inum: inode number
269 * @block: block number
270 */
data_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,unsigned int block)271 static inline void data_key_init(const struct ubifs_info *c,
272 union ubifs_key *key, ino_t inum,
273 unsigned int block)
274 {
275 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
276 key->u32[0] = inum;
277 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
278 }
279
280 /**
281 * highest_data_key - get the highest possible data key for an inode.
282 * @c: UBIFS file-system description object
283 * @key: key to initialize
284 * @inum: inode number
285 */
highest_data_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)286 static inline void highest_data_key(const struct ubifs_info *c,
287 union ubifs_key *key, ino_t inum)
288 {
289 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
290 }
291
292 /**
293 * trun_key_init - initialize truncation node key.
294 * @c: UBIFS file-system description object
295 * @key: key to initialize
296 * @inum: inode number
297 *
298 * Note, UBIFS does not have truncation keys on the media and this function is
299 * only used for purposes of replay.
300 */
trun_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)301 static inline void trun_key_init(const struct ubifs_info *c,
302 union ubifs_key *key, ino_t inum)
303 {
304 key->u32[0] = inum;
305 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
306 }
307
308 /**
309 * invalid_key_init - initialize invalid node key.
310 * @c: UBIFS file-system description object
311 * @key: key to initialize
312 *
313 * This is a helper function which marks a @key object as invalid.
314 */
invalid_key_init(const struct ubifs_info * c,union ubifs_key * key)315 static inline void invalid_key_init(const struct ubifs_info *c,
316 union ubifs_key *key)
317 {
318 key->u32[0] = 0xDEADBEAF;
319 key->u32[1] = UBIFS_INVALID_KEY;
320 }
321
322 /**
323 * key_type - get key type.
324 * @c: UBIFS file-system description object
325 * @key: key to get type of
326 */
key_type(const struct ubifs_info * c,const union ubifs_key * key)327 static inline int key_type(const struct ubifs_info *c,
328 const union ubifs_key *key)
329 {
330 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
331 }
332
333 /**
334 * key_type_flash - get type of a on-flash formatted key.
335 * @c: UBIFS file-system description object
336 * @k: key to get type of
337 */
key_type_flash(const struct ubifs_info * c,const void * k)338 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
339 {
340 const union ubifs_key *key = k;
341
342 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
343 }
344
345 /**
346 * key_inum - fetch inode number from key.
347 * @c: UBIFS file-system description object
348 * @k: key to fetch inode number from
349 */
key_inum(const struct ubifs_info * c,const void * k)350 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
351 {
352 const union ubifs_key *key = k;
353
354 return key->u32[0];
355 }
356
357 /**
358 * key_inum_flash - fetch inode number from an on-flash formatted key.
359 * @c: UBIFS file-system description object
360 * @k: key to fetch inode number from
361 */
key_inum_flash(const struct ubifs_info * c,const void * k)362 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
363 {
364 const union ubifs_key *key = k;
365
366 return le32_to_cpu(key->j32[0]);
367 }
368
369 /**
370 * key_hash - get directory entry hash.
371 * @c: UBIFS file-system description object
372 * @key: the key to get hash from
373 */
key_hash(const struct ubifs_info * c,const union ubifs_key * key)374 static inline uint32_t key_hash(const struct ubifs_info *c,
375 const union ubifs_key *key)
376 {
377 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
378 }
379
380 /**
381 * key_hash_flash - get directory entry hash from an on-flash formatted key.
382 * @c: UBIFS file-system description object
383 * @k: the key to get hash from
384 */
key_hash_flash(const struct ubifs_info * c,const void * k)385 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
386 {
387 const union ubifs_key *key = k;
388
389 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
390 }
391
392 /**
393 * key_block - get data block number.
394 * @c: UBIFS file-system description object
395 * @key: the key to get the block number from
396 */
key_block(const struct ubifs_info * c,const union ubifs_key * key)397 static inline unsigned int key_block(const struct ubifs_info *c,
398 const union ubifs_key *key)
399 {
400 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
401 }
402
403 /**
404 * key_block_flash - get data block number from an on-flash formatted key.
405 * @c: UBIFS file-system description object
406 * @k: the key to get the block number from
407 */
key_block_flash(const struct ubifs_info * c,const void * k)408 static inline unsigned int key_block_flash(const struct ubifs_info *c,
409 const void *k)
410 {
411 const union ubifs_key *key = k;
412
413 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
414 }
415
416 /**
417 * key_read - transform a key to in-memory format.
418 * @c: UBIFS file-system description object
419 * @from: the key to transform
420 * @to: the key to store the result
421 */
key_read(const struct ubifs_info * c,const void * from,union ubifs_key * to)422 static inline void key_read(const struct ubifs_info *c, const void *from,
423 union ubifs_key *to)
424 {
425 const union ubifs_key *f = from;
426
427 to->u32[0] = le32_to_cpu(f->j32[0]);
428 to->u32[1] = le32_to_cpu(f->j32[1]);
429 }
430
431 /**
432 * key_write - transform a key from in-memory format.
433 * @c: UBIFS file-system description object
434 * @from: the key to transform
435 * @to: the key to store the result
436 */
key_write(const struct ubifs_info * c,const union ubifs_key * from,void * to)437 static inline void key_write(const struct ubifs_info *c,
438 const union ubifs_key *from, void *to)
439 {
440 union ubifs_key *t = to;
441
442 t->j32[0] = cpu_to_le32(from->u32[0]);
443 t->j32[1] = cpu_to_le32(from->u32[1]);
444 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
445 }
446
447 /**
448 * key_write_idx - transform a key from in-memory format for the index.
449 * @c: UBIFS file-system description object
450 * @from: the key to transform
451 * @to: the key to store the result
452 */
key_write_idx(const struct ubifs_info * c,const union ubifs_key * from,void * to)453 static inline void key_write_idx(const struct ubifs_info *c,
454 const union ubifs_key *from, void *to)
455 {
456 union ubifs_key *t = to;
457
458 t->j32[0] = cpu_to_le32(from->u32[0]);
459 t->j32[1] = cpu_to_le32(from->u32[1]);
460 }
461
462 /**
463 * key_copy - copy a key.
464 * @c: UBIFS file-system description object
465 * @from: the key to copy from
466 * @to: the key to copy to
467 */
key_copy(const struct ubifs_info * c,const union ubifs_key * from,union ubifs_key * to)468 static inline void key_copy(const struct ubifs_info *c,
469 const union ubifs_key *from, union ubifs_key *to)
470 {
471 to->u64[0] = from->u64[0];
472 }
473
474 /**
475 * keys_cmp - compare keys.
476 * @c: UBIFS file-system description object
477 * @key1: the first key to compare
478 * @key2: the second key to compare
479 *
480 * This function compares 2 keys and returns %-1 if @key1 is less than
481 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
482 */
keys_cmp(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)483 static inline int keys_cmp(const struct ubifs_info *c,
484 const union ubifs_key *key1,
485 const union ubifs_key *key2)
486 {
487 if (key1->u32[0] < key2->u32[0])
488 return -1;
489 if (key1->u32[0] > key2->u32[0])
490 return 1;
491 if (key1->u32[1] < key2->u32[1])
492 return -1;
493 if (key1->u32[1] > key2->u32[1])
494 return 1;
495
496 return 0;
497 }
498
499 /**
500 * keys_eq - determine if keys are equivalent.
501 * @c: UBIFS file-system description object
502 * @key1: the first key to compare
503 * @key2: the second key to compare
504 *
505 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
506 * %0 if not.
507 */
keys_eq(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)508 static inline int keys_eq(const struct ubifs_info *c,
509 const union ubifs_key *key1,
510 const union ubifs_key *key2)
511 {
512 if (key1->u32[0] != key2->u32[0])
513 return 0;
514 if (key1->u32[1] != key2->u32[1])
515 return 0;
516 return 1;
517 }
518
519 /**
520 * is_hash_key - is a key vulnerable to hash collisions.
521 * @c: UBIFS file-system description object
522 * @key: key
523 *
524 * This function returns %1 if @key is a hashed key or %0 otherwise.
525 */
is_hash_key(const struct ubifs_info * c,const union ubifs_key * key)526 static inline int is_hash_key(const struct ubifs_info *c,
527 const union ubifs_key *key)
528 {
529 int type = key_type(c, key);
530
531 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
532 }
533
534 /**
535 * key_max_inode_size - get maximum file size allowed by current key format.
536 * @c: UBIFS file-system description object
537 */
key_max_inode_size(const struct ubifs_info * c)538 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
539 {
540 switch (c->key_fmt) {
541 case UBIFS_SIMPLE_KEY_FMT:
542 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
543 default:
544 return 0;
545 }
546 }
547
548 #endif /* !__UBIFS_KEY_H__ */
549