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 /*
38 * Lot's of the key helpers require a struct ubifs_info *c as the first parameter.
39 * But we are not using it at all currently. That's designed for future extensions of
40 * different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.
41 */
42
43 #ifndef __UBIFS_KEY_H__
44 #define __UBIFS_KEY_H__
45
46 /**
47 * key_mask_hash - mask a valid hash value.
48 * @val: value to be masked
49 *
50 * We use hash values as offset in directories, so values %0 and %1 are
51 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
52 * function makes sure the reserved values are not used.
53 */
key_mask_hash(uint32_t hash)54 static inline uint32_t key_mask_hash(uint32_t hash)
55 {
56 hash &= UBIFS_S_KEY_HASH_MASK;
57 if (unlikely(hash <= 2))
58 hash += 3;
59 return hash;
60 }
61
62 /**
63 * key_r5_hash - R5 hash function (borrowed from reiserfs).
64 * @s: direntry name
65 * @len: name length
66 */
key_r5_hash(const char * s,int len)67 static inline uint32_t key_r5_hash(const char *s, int len)
68 {
69 uint32_t a = 0;
70 const signed char *str = (const signed char *)s;
71
72 while (*str) {
73 a += *str << 4;
74 a += *str >> 4;
75 a *= 11;
76 str++;
77 }
78
79 return key_mask_hash(a);
80 }
81
82 /**
83 * key_test_hash - testing hash function.
84 * @str: direntry name
85 * @len: name length
86 */
key_test_hash(const char * str,int len)87 static inline uint32_t key_test_hash(const char *str, int len)
88 {
89 uint32_t a = 0;
90
91 len = min_t(uint32_t, len, 4);
92 memcpy(&a, str, len);
93 return key_mask_hash(a);
94 }
95
96 /**
97 * ino_key_init - initialize inode key.
98 * @c: UBIFS file-system description object
99 * @key: key to initialize
100 * @inum: inode number
101 */
ino_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)102 static inline void ino_key_init(const struct ubifs_info *c,
103 union ubifs_key *key, ino_t inum)
104 {
105 key->u32[0] = inum;
106 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
107 }
108
109 /**
110 * ino_key_init_flash - initialize on-flash inode key.
111 * @c: UBIFS file-system description object
112 * @k: key to initialize
113 * @inum: inode number
114 */
ino_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum)115 static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
116 ino_t inum)
117 {
118 union ubifs_key *key = k;
119
120 key->j32[0] = cpu_to_le32(inum);
121 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
122 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
123 }
124
125 /**
126 * lowest_ino_key - get the lowest possible inode key.
127 * @c: UBIFS file-system description object
128 * @key: key to initialize
129 * @inum: inode number
130 */
lowest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)131 static inline void lowest_ino_key(const struct ubifs_info *c,
132 union ubifs_key *key, ino_t inum)
133 {
134 key->u32[0] = inum;
135 key->u32[1] = 0;
136 }
137
138 /**
139 * highest_ino_key - get the highest possible inode key.
140 * @c: UBIFS file-system description object
141 * @key: key to initialize
142 * @inum: inode number
143 */
highest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)144 static inline void highest_ino_key(const struct ubifs_info *c,
145 union ubifs_key *key, ino_t inum)
146 {
147 key->u32[0] = inum;
148 key->u32[1] = 0xffffffff;
149 }
150
151 /**
152 * dent_key_init - initialize directory entry key.
153 * @c: UBIFS file-system description object
154 * @key: key to initialize
155 * @inum: parent inode number
156 * @nm: direntry name and length
157 */
dent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)158 static inline void dent_key_init(const struct ubifs_info *c,
159 union ubifs_key *key, ino_t inum,
160 const struct qstr *nm)
161 {
162 uint32_t hash = c->key_hash(nm->name, nm->len);
163
164 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
165 key->u32[0] = inum;
166 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
167 }
168
169 /**
170 * dent_key_init_hash - initialize directory entry key without re-calculating
171 * hash function.
172 * @c: UBIFS file-system description object
173 * @key: key to initialize
174 * @inum: parent inode number
175 * @hash: direntry name hash
176 */
dent_key_init_hash(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,uint32_t hash)177 static inline void dent_key_init_hash(const struct ubifs_info *c,
178 union ubifs_key *key, ino_t inum,
179 uint32_t hash)
180 {
181 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
182 key->u32[0] = inum;
183 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
184 }
185
186 /**
187 * dent_key_init_flash - initialize on-flash directory entry key.
188 * @c: UBIFS file-system description object
189 * @k: key to initialize
190 * @inum: parent inode number
191 * @nm: direntry name and length
192 */
dent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)193 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
194 ino_t inum, const struct qstr *nm)
195 {
196 union ubifs_key *key = k;
197 uint32_t hash = c->key_hash(nm->name, nm->len);
198
199 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
200 key->j32[0] = cpu_to_le32(inum);
201 key->j32[1] = cpu_to_le32(hash |
202 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
203 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
204 }
205
206 /**
207 * lowest_dent_key - get the lowest possible directory entry key.
208 * @c: UBIFS file-system description object
209 * @key: where to store the lowest key
210 * @inum: parent inode number
211 */
lowest_dent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)212 static inline void lowest_dent_key(const struct ubifs_info *c,
213 union ubifs_key *key, ino_t inum)
214 {
215 key->u32[0] = inum;
216 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
217 }
218
219 /**
220 * xent_key_init - initialize extended attribute entry key.
221 * @c: UBIFS file-system description object
222 * @key: key to initialize
223 * @inum: host inode number
224 * @nm: extended attribute entry name and length
225 */
xent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)226 static inline void xent_key_init(const struct ubifs_info *c,
227 union ubifs_key *key, ino_t inum,
228 const struct qstr *nm)
229 {
230 uint32_t hash = c->key_hash(nm->name, nm->len);
231
232 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
233 key->u32[0] = inum;
234 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
235 }
236
237 /**
238 * xent_key_init_flash - initialize on-flash extended attribute entry key.
239 * @c: UBIFS file-system description object
240 * @k: key to initialize
241 * @inum: host inode number
242 * @nm: extended attribute entry name and length
243 */
xent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)244 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
245 ino_t inum, const struct qstr *nm)
246 {
247 union ubifs_key *key = k;
248 uint32_t hash = c->key_hash(nm->name, nm->len);
249
250 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
251 key->j32[0] = cpu_to_le32(inum);
252 key->j32[1] = cpu_to_le32(hash |
253 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
254 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
255 }
256
257 /**
258 * lowest_xent_key - get the lowest possible extended attribute entry key.
259 * @c: UBIFS file-system description object
260 * @key: where to store the lowest key
261 * @inum: host inode number
262 */
lowest_xent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)263 static inline void lowest_xent_key(const struct ubifs_info *c,
264 union ubifs_key *key, ino_t inum)
265 {
266 key->u32[0] = inum;
267 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
268 }
269
270 /**
271 * data_key_init - initialize data key.
272 * @c: UBIFS file-system description object
273 * @key: key to initialize
274 * @inum: inode number
275 * @block: block number
276 */
data_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,unsigned int block)277 static inline void data_key_init(const struct ubifs_info *c,
278 union ubifs_key *key, ino_t inum,
279 unsigned int block)
280 {
281 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
282 key->u32[0] = inum;
283 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
284 }
285
286 /**
287 * highest_data_key - get the highest possible data key for an inode.
288 * @c: UBIFS file-system description object
289 * @key: key to initialize
290 * @inum: inode number
291 */
highest_data_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)292 static inline void highest_data_key(const struct ubifs_info *c,
293 union ubifs_key *key, ino_t inum)
294 {
295 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
296 }
297
298 /**
299 * trun_key_init - initialize truncation node key.
300 * @c: UBIFS file-system description object
301 * @key: key to initialize
302 * @inum: inode number
303 *
304 * Note, UBIFS does not have truncation keys on the media and this function is
305 * only used for purposes of replay.
306 */
trun_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)307 static inline void trun_key_init(const struct ubifs_info *c,
308 union ubifs_key *key, ino_t inum)
309 {
310 key->u32[0] = inum;
311 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
312 }
313
314 /**
315 * invalid_key_init - initialize invalid node key.
316 * @c: UBIFS file-system description object
317 * @key: key to initialize
318 *
319 * This is a helper function which marks a @key object as invalid.
320 */
invalid_key_init(const struct ubifs_info * c,union ubifs_key * key)321 static inline void invalid_key_init(const struct ubifs_info *c,
322 union ubifs_key *key)
323 {
324 key->u32[0] = 0xDEADBEAF;
325 key->u32[1] = UBIFS_INVALID_KEY;
326 }
327
328 /**
329 * key_type - get key type.
330 * @c: UBIFS file-system description object
331 * @key: key to get type of
332 */
key_type(const struct ubifs_info * c,const union ubifs_key * key)333 static inline int key_type(const struct ubifs_info *c,
334 const union ubifs_key *key)
335 {
336 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
337 }
338
339 /**
340 * key_type_flash - get type of a on-flash formatted key.
341 * @c: UBIFS file-system description object
342 * @k: key to get type of
343 */
key_type_flash(const struct ubifs_info * c,const void * k)344 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
345 {
346 const union ubifs_key *key = k;
347
348 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
349 }
350
351 /**
352 * key_inum - fetch inode number from key.
353 * @c: UBIFS file-system description object
354 * @k: key to fetch inode number from
355 */
key_inum(const struct ubifs_info * c,const void * k)356 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
357 {
358 const union ubifs_key *key = k;
359
360 return key->u32[0];
361 }
362
363 /**
364 * key_inum_flash - fetch inode number from an on-flash formatted key.
365 * @c: UBIFS file-system description object
366 * @k: key to fetch inode number from
367 */
key_inum_flash(const struct ubifs_info * c,const void * k)368 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
369 {
370 const union ubifs_key *key = k;
371
372 return le32_to_cpu(key->j32[0]);
373 }
374
375 /**
376 * key_hash - get directory entry hash.
377 * @c: UBIFS file-system description object
378 * @key: the key to get hash from
379 */
key_hash(const struct ubifs_info * c,const union ubifs_key * key)380 static inline uint32_t key_hash(const struct ubifs_info *c,
381 const union ubifs_key *key)
382 {
383 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
384 }
385
386 /**
387 * key_hash_flash - get directory entry hash from an on-flash formatted key.
388 * @c: UBIFS file-system description object
389 * @k: the key to get hash from
390 */
key_hash_flash(const struct ubifs_info * c,const void * k)391 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
392 {
393 const union ubifs_key *key = k;
394
395 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
396 }
397
398 /**
399 * key_block - get data block number.
400 * @c: UBIFS file-system description object
401 * @key: the key to get the block number from
402 */
key_block(const struct ubifs_info * c,const union ubifs_key * key)403 static inline unsigned int key_block(const struct ubifs_info *c,
404 const union ubifs_key *key)
405 {
406 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
407 }
408
409 /**
410 * key_block_flash - get data block number from an on-flash formatted key.
411 * @c: UBIFS file-system description object
412 * @k: the key to get the block number from
413 */
key_block_flash(const struct ubifs_info * c,const void * k)414 static inline unsigned int key_block_flash(const struct ubifs_info *c,
415 const void *k)
416 {
417 const union ubifs_key *key = k;
418
419 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
420 }
421
422 /**
423 * key_read - transform a key to in-memory format.
424 * @c: UBIFS file-system description object
425 * @from: the key to transform
426 * @to: the key to store the result
427 */
key_read(const struct ubifs_info * c,const void * from,union ubifs_key * to)428 static inline void key_read(const struct ubifs_info *c, const void *from,
429 union ubifs_key *to)
430 {
431 const union ubifs_key *f = from;
432
433 to->u32[0] = le32_to_cpu(f->j32[0]);
434 to->u32[1] = le32_to_cpu(f->j32[1]);
435 }
436
437 /**
438 * key_write - transform a key from in-memory format.
439 * @c: UBIFS file-system description object
440 * @from: the key to transform
441 * @to: the key to store the result
442 */
key_write(const struct ubifs_info * c,const union ubifs_key * from,void * to)443 static inline void key_write(const struct ubifs_info *c,
444 const union ubifs_key *from, void *to)
445 {
446 union ubifs_key *t = to;
447
448 t->j32[0] = cpu_to_le32(from->u32[0]);
449 t->j32[1] = cpu_to_le32(from->u32[1]);
450 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
451 }
452
453 /**
454 * key_write_idx - transform a key from in-memory format for the index.
455 * @c: UBIFS file-system description object
456 * @from: the key to transform
457 * @to: the key to store the result
458 */
key_write_idx(const struct ubifs_info * c,const union ubifs_key * from,void * to)459 static inline void key_write_idx(const struct ubifs_info *c,
460 const union ubifs_key *from, void *to)
461 {
462 union ubifs_key *t = to;
463
464 t->j32[0] = cpu_to_le32(from->u32[0]);
465 t->j32[1] = cpu_to_le32(from->u32[1]);
466 }
467
468 /**
469 * key_copy - copy a key.
470 * @c: UBIFS file-system description object
471 * @from: the key to copy from
472 * @to: the key to copy to
473 */
key_copy(const struct ubifs_info * c,const union ubifs_key * from,union ubifs_key * to)474 static inline void key_copy(const struct ubifs_info *c,
475 const union ubifs_key *from, union ubifs_key *to)
476 {
477 to->u64[0] = from->u64[0];
478 }
479
480 /**
481 * keys_cmp - compare keys.
482 * @c: UBIFS file-system description object
483 * @key1: the first key to compare
484 * @key2: the second key to compare
485 *
486 * This function compares 2 keys and returns %-1 if @key1 is less than
487 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
488 */
keys_cmp(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)489 static inline int keys_cmp(const struct ubifs_info *c,
490 const union ubifs_key *key1,
491 const union ubifs_key *key2)
492 {
493 if (key1->u32[0] < key2->u32[0])
494 return -1;
495 if (key1->u32[0] > key2->u32[0])
496 return 1;
497 if (key1->u32[1] < key2->u32[1])
498 return -1;
499 if (key1->u32[1] > key2->u32[1])
500 return 1;
501
502 return 0;
503 }
504
505 /**
506 * keys_eq - determine if keys are equivalent.
507 * @c: UBIFS file-system description object
508 * @key1: the first key to compare
509 * @key2: the second key to compare
510 *
511 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
512 * %0 if not.
513 */
keys_eq(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)514 static inline int keys_eq(const struct ubifs_info *c,
515 const union ubifs_key *key1,
516 const union ubifs_key *key2)
517 {
518 if (key1->u32[0] != key2->u32[0])
519 return 0;
520 if (key1->u32[1] != key2->u32[1])
521 return 0;
522 return 1;
523 }
524
525 /**
526 * is_hash_key - is a key vulnerable to hash collisions.
527 * @c: UBIFS file-system description object
528 * @key: key
529 *
530 * This function returns %1 if @key is a hashed key or %0 otherwise.
531 */
is_hash_key(const struct ubifs_info * c,const union ubifs_key * key)532 static inline int is_hash_key(const struct ubifs_info *c,
533 const union ubifs_key *key)
534 {
535 int type = key_type(c, key);
536
537 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
538 }
539
540 /**
541 * key_max_inode_size - get maximum file size allowed by current key format.
542 * @c: UBIFS file-system description object
543 */
key_max_inode_size(const struct ubifs_info * c)544 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
545 {
546 switch (c->key_fmt) {
547 case UBIFS_SIMPLE_KEY_FMT:
548 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
549 default:
550 return 0;
551 }
552 }
553
554 #endif /* !__UBIFS_KEY_H__ */
555