1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation.
6 *
7 * Authors: Artem Bityutskiy (Битюцкий Артём)
8 * Adrian Hunter
9 */
10
11 /*
12 * This header contains various key-related definitions and helper function.
13 * UBIFS allows several key schemes, so we access key fields only via these
14 * helpers. At the moment only one key scheme is supported.
15 *
16 * Simple key scheme
17 * ~~~~~~~~~~~~~~~~~
18 *
19 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
20 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
21 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
22 * node. We use "r5" hash borrowed from reiserfs.
23 */
24
25 #ifndef __UBIFS_KEY_H__
26 #define __UBIFS_KEY_H__
27
28 /**
29 * key_mask_hash - mask a valid hash value.
30 * @val: value to be masked
31 *
32 * We use hash values as offset in directories, so values %0 and %1 are
33 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
34 * function makes sure the reserved values are not used.
35 */
key_mask_hash(uint32_t hash)36 static inline uint32_t key_mask_hash(uint32_t hash)
37 {
38 hash &= UBIFS_S_KEY_HASH_MASK;
39 if (unlikely(hash <= 2))
40 hash += 3;
41 return hash;
42 }
43
44 /**
45 * key_r5_hash - R5 hash function (borrowed from reiserfs).
46 * @s: direntry name
47 * @len: name length
48 */
key_r5_hash(const char * s,int len)49 static inline uint32_t key_r5_hash(const char *s, int len)
50 {
51 uint32_t a = 0;
52 const signed char *str = (const signed char *)s;
53
54 while (*str) {
55 a += *str << 4;
56 a += *str >> 4;
57 a *= 11;
58 str++;
59 }
60
61 return key_mask_hash(a);
62 }
63
64 /**
65 * key_test_hash - testing hash function.
66 * @str: direntry name
67 * @len: name length
68 */
key_test_hash(const char * str,int len)69 static inline uint32_t key_test_hash(const char *str, int len)
70 {
71 uint32_t a = 0;
72
73 len = min_t(uint32_t, len, 4);
74 memcpy(&a, str, len);
75 return key_mask_hash(a);
76 }
77
78 /**
79 * ino_key_init - initialize inode key.
80 * @c: UBIFS file-system description object
81 * @key: key to initialize
82 * @inum: inode number
83 */
ino_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)84 static inline void ino_key_init(const struct ubifs_info *c,
85 union ubifs_key *key, ino_t inum)
86 {
87 key->u32[0] = inum;
88 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
89 }
90
91 /**
92 * ino_key_init_flash - initialize on-flash inode key.
93 * @c: UBIFS file-system description object
94 * @k: key to initialize
95 * @inum: inode number
96 */
ino_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum)97 static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
98 ino_t inum)
99 {
100 union ubifs_key *key = k;
101
102 key->j32[0] = cpu_to_le32(inum);
103 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
104 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
105 }
106
107 /**
108 * lowest_ino_key - get the lowest possible inode key.
109 * @c: UBIFS file-system description object
110 * @key: key to initialize
111 * @inum: inode number
112 */
lowest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)113 static inline void lowest_ino_key(const struct ubifs_info *c,
114 union ubifs_key *key, ino_t inum)
115 {
116 key->u32[0] = inum;
117 key->u32[1] = 0;
118 }
119
120 /**
121 * highest_ino_key - get the highest possible inode key.
122 * @c: UBIFS file-system description object
123 * @key: key to initialize
124 * @inum: inode number
125 */
highest_ino_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)126 static inline void highest_ino_key(const struct ubifs_info *c,
127 union ubifs_key *key, ino_t inum)
128 {
129 key->u32[0] = inum;
130 key->u32[1] = 0xffffffff;
131 }
132
133 /**
134 * dent_key_init - initialize directory entry key.
135 * @c: UBIFS file-system description object
136 * @key: key to initialize
137 * @inum: parent inode number
138 * @nm: direntry name and length
139 */
dent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)140 static inline void dent_key_init(const struct ubifs_info *c,
141 union ubifs_key *key, ino_t inum,
142 const struct qstr *nm)
143 {
144 uint32_t hash = c->key_hash(nm->name, nm->len);
145
146 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
147 key->u32[0] = inum;
148 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
149 }
150
151 /**
152 * dent_key_init_hash - initialize directory entry key without re-calculating
153 * hash function.
154 * @c: UBIFS file-system description object
155 * @key: key to initialize
156 * @inum: parent inode number
157 * @hash: direntry name hash
158 */
dent_key_init_hash(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,uint32_t hash)159 static inline void dent_key_init_hash(const struct ubifs_info *c,
160 union ubifs_key *key, ino_t inum,
161 uint32_t hash)
162 {
163 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
164 key->u32[0] = inum;
165 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
166 }
167
168 /**
169 * dent_key_init_flash - initialize on-flash directory entry key.
170 * @c: UBIFS file-system description object
171 * @k: key to initialize
172 * @inum: parent inode number
173 * @nm: direntry name and length
174 */
dent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)175 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
176 ino_t inum, const struct qstr *nm)
177 {
178 union ubifs_key *key = k;
179 uint32_t hash = c->key_hash(nm->name, nm->len);
180
181 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
182 key->j32[0] = cpu_to_le32(inum);
183 key->j32[1] = cpu_to_le32(hash |
184 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
185 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
186 }
187
188 /**
189 * lowest_dent_key - get the lowest possible directory entry key.
190 * @c: UBIFS file-system description object
191 * @key: where to store the lowest key
192 * @inum: parent inode number
193 */
lowest_dent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)194 static inline void lowest_dent_key(const struct ubifs_info *c,
195 union ubifs_key *key, ino_t inum)
196 {
197 key->u32[0] = inum;
198 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
199 }
200
201 /**
202 * xent_key_init - initialize extended attribute entry key.
203 * @c: UBIFS file-system description object
204 * @key: key to initialize
205 * @inum: host inode number
206 * @nm: extended attribute entry name and length
207 */
xent_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,const struct qstr * nm)208 static inline void xent_key_init(const struct ubifs_info *c,
209 union ubifs_key *key, ino_t inum,
210 const struct qstr *nm)
211 {
212 uint32_t hash = c->key_hash(nm->name, nm->len);
213
214 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
215 key->u32[0] = inum;
216 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
217 }
218
219 /**
220 * xent_key_init_flash - initialize on-flash extended attribute entry key.
221 * @c: UBIFS file-system description object
222 * @k: key to initialize
223 * @inum: host inode number
224 * @nm: extended attribute entry name and length
225 */
xent_key_init_flash(const struct ubifs_info * c,void * k,ino_t inum,const struct qstr * nm)226 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
227 ino_t inum, const struct qstr *nm)
228 {
229 union ubifs_key *key = k;
230 uint32_t hash = c->key_hash(nm->name, nm->len);
231
232 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
233 key->j32[0] = cpu_to_le32(inum);
234 key->j32[1] = cpu_to_le32(hash |
235 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
236 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
237 }
238
239 /**
240 * lowest_xent_key - get the lowest possible extended attribute entry key.
241 * @c: UBIFS file-system description object
242 * @key: where to store the lowest key
243 * @inum: host inode number
244 */
lowest_xent_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)245 static inline void lowest_xent_key(const struct ubifs_info *c,
246 union ubifs_key *key, ino_t inum)
247 {
248 key->u32[0] = inum;
249 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
250 }
251
252 /**
253 * data_key_init - initialize data key.
254 * @c: UBIFS file-system description object
255 * @key: key to initialize
256 * @inum: inode number
257 * @block: block number
258 */
data_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum,unsigned int block)259 static inline void data_key_init(const struct ubifs_info *c,
260 union ubifs_key *key, ino_t inum,
261 unsigned int block)
262 {
263 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
264 key->u32[0] = inum;
265 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
266 }
267
268 /**
269 * highest_data_key - get the highest possible data key for an inode.
270 * @c: UBIFS file-system description object
271 * @key: key to initialize
272 * @inum: inode number
273 */
highest_data_key(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)274 static inline void highest_data_key(const struct ubifs_info *c,
275 union ubifs_key *key, ino_t inum)
276 {
277 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
278 }
279
280 /**
281 * trun_key_init - initialize truncation node key.
282 * @c: UBIFS file-system description object
283 * @key: key to initialize
284 * @inum: inode number
285 *
286 * Note, UBIFS does not have truncation keys on the media and this function is
287 * only used for purposes of replay.
288 */
trun_key_init(const struct ubifs_info * c,union ubifs_key * key,ino_t inum)289 static inline void trun_key_init(const struct ubifs_info *c,
290 union ubifs_key *key, ino_t inum)
291 {
292 key->u32[0] = inum;
293 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
294 }
295
296 /**
297 * invalid_key_init - initialize invalid node key.
298 * @c: UBIFS file-system description object
299 * @key: key to initialize
300 *
301 * This is a helper function which marks a @key object as invalid.
302 */
invalid_key_init(const struct ubifs_info * c,union ubifs_key * key)303 static inline void invalid_key_init(const struct ubifs_info *c,
304 union ubifs_key *key)
305 {
306 key->u32[0] = 0xDEADBEAF;
307 key->u32[1] = UBIFS_INVALID_KEY;
308 }
309
310 /**
311 * key_type - get key type.
312 * @c: UBIFS file-system description object
313 * @key: key to get type of
314 */
key_type(const struct ubifs_info * c,const union ubifs_key * key)315 static inline int key_type(const struct ubifs_info *c,
316 const union ubifs_key *key)
317 {
318 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
319 }
320
321 /**
322 * key_type_flash - get type of a on-flash formatted key.
323 * @c: UBIFS file-system description object
324 * @k: key to get type of
325 */
key_type_flash(const struct ubifs_info * c,const void * k)326 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
327 {
328 const union ubifs_key *key = k;
329
330 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
331 }
332
333 /**
334 * key_inum - fetch inode number from key.
335 * @c: UBIFS file-system description object
336 * @k: key to fetch inode number from
337 */
key_inum(const struct ubifs_info * c,const void * k)338 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
339 {
340 const union ubifs_key *key = k;
341
342 return key->u32[0];
343 }
344
345 /**
346 * key_inum_flash - fetch inode number from an on-flash formatted key.
347 * @c: UBIFS file-system description object
348 * @k: key to fetch inode number from
349 */
key_inum_flash(const struct ubifs_info * c,const void * k)350 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
351 {
352 const union ubifs_key *key = k;
353
354 return le32_to_cpu(key->j32[0]);
355 }
356
357 /**
358 * key_hash - get directory entry hash.
359 * @c: UBIFS file-system description object
360 * @key: the key to get hash from
361 */
key_hash(const struct ubifs_info * c,const union ubifs_key * key)362 static inline uint32_t key_hash(const struct ubifs_info *c,
363 const union ubifs_key *key)
364 {
365 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
366 }
367
368 /**
369 * key_hash_flash - get directory entry hash from an on-flash formatted key.
370 * @c: UBIFS file-system description object
371 * @k: the key to get hash from
372 */
key_hash_flash(const struct ubifs_info * c,const void * k)373 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
374 {
375 const union ubifs_key *key = k;
376
377 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
378 }
379
380 /**
381 * key_block - get data block number.
382 * @c: UBIFS file-system description object
383 * @key: the key to get the block number from
384 */
key_block(const struct ubifs_info * c,const union ubifs_key * key)385 static inline unsigned int key_block(const struct ubifs_info *c,
386 const union ubifs_key *key)
387 {
388 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
389 }
390
391 /**
392 * key_block_flash - get data block number from an on-flash formatted key.
393 * @c: UBIFS file-system description object
394 * @k: the key to get the block number from
395 */
key_block_flash(const struct ubifs_info * c,const void * k)396 static inline unsigned int key_block_flash(const struct ubifs_info *c,
397 const void *k)
398 {
399 const union ubifs_key *key = k;
400
401 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
402 }
403
404 /**
405 * key_read - transform a key to in-memory format.
406 * @c: UBIFS file-system description object
407 * @from: the key to transform
408 * @to: the key to store the result
409 */
key_read(const struct ubifs_info * c,const void * from,union ubifs_key * to)410 static inline void key_read(const struct ubifs_info *c, const void *from,
411 union ubifs_key *to)
412 {
413 const union ubifs_key *f = from;
414
415 to->u32[0] = le32_to_cpu(f->j32[0]);
416 to->u32[1] = le32_to_cpu(f->j32[1]);
417 }
418
419 /**
420 * key_write - transform a key from in-memory format.
421 * @c: UBIFS file-system description object
422 * @from: the key to transform
423 * @to: the key to store the result
424 */
key_write(const struct ubifs_info * c,const union ubifs_key * from,void * to)425 static inline void key_write(const struct ubifs_info *c,
426 const union ubifs_key *from, void *to)
427 {
428 union ubifs_key *t = to;
429
430 t->j32[0] = cpu_to_le32(from->u32[0]);
431 t->j32[1] = cpu_to_le32(from->u32[1]);
432 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
433 }
434
435 /**
436 * key_write_idx - transform a key from in-memory format for the index.
437 * @c: UBIFS file-system description object
438 * @from: the key to transform
439 * @to: the key to store the result
440 */
key_write_idx(const struct ubifs_info * c,const union ubifs_key * from,void * to)441 static inline void key_write_idx(const struct ubifs_info *c,
442 const union ubifs_key *from, void *to)
443 {
444 union ubifs_key *t = to;
445
446 t->j32[0] = cpu_to_le32(from->u32[0]);
447 t->j32[1] = cpu_to_le32(from->u32[1]);
448 }
449
450 /**
451 * key_copy - copy a key.
452 * @c: UBIFS file-system description object
453 * @from: the key to copy from
454 * @to: the key to copy to
455 */
key_copy(const struct ubifs_info * c,const union ubifs_key * from,union ubifs_key * to)456 static inline void key_copy(const struct ubifs_info *c,
457 const union ubifs_key *from, union ubifs_key *to)
458 {
459 to->u64[0] = from->u64[0];
460 }
461
462 /**
463 * keys_cmp - compare keys.
464 * @c: UBIFS file-system description object
465 * @key1: the first key to compare
466 * @key2: the second key to compare
467 *
468 * This function compares 2 keys and returns %-1 if @key1 is less than
469 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
470 */
keys_cmp(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)471 static inline int keys_cmp(const struct ubifs_info *c,
472 const union ubifs_key *key1,
473 const union ubifs_key *key2)
474 {
475 if (key1->u32[0] < key2->u32[0])
476 return -1;
477 if (key1->u32[0] > key2->u32[0])
478 return 1;
479 if (key1->u32[1] < key2->u32[1])
480 return -1;
481 if (key1->u32[1] > key2->u32[1])
482 return 1;
483
484 return 0;
485 }
486
487 /**
488 * keys_eq - determine if keys are equivalent.
489 * @c: UBIFS file-system description object
490 * @key1: the first key to compare
491 * @key2: the second key to compare
492 *
493 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
494 * %0 if not.
495 */
keys_eq(const struct ubifs_info * c,const union ubifs_key * key1,const union ubifs_key * key2)496 static inline int keys_eq(const struct ubifs_info *c,
497 const union ubifs_key *key1,
498 const union ubifs_key *key2)
499 {
500 if (key1->u32[0] != key2->u32[0])
501 return 0;
502 if (key1->u32[1] != key2->u32[1])
503 return 0;
504 return 1;
505 }
506
507 /**
508 * is_hash_key - is a key vulnerable to hash collisions.
509 * @c: UBIFS file-system description object
510 * @key: key
511 *
512 * This function returns %1 if @key is a hashed key or %0 otherwise.
513 */
is_hash_key(const struct ubifs_info * c,const union ubifs_key * key)514 static inline int is_hash_key(const struct ubifs_info *c,
515 const union ubifs_key *key)
516 {
517 int type = key_type(c, key);
518
519 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
520 }
521
522 /**
523 * key_max_inode_size - get maximum file size allowed by current key format.
524 * @c: UBIFS file-system description object
525 */
key_max_inode_size(const struct ubifs_info * c)526 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
527 {
528 switch (c->key_fmt) {
529 case UBIFS_SIMPLE_KEY_FMT:
530 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
531 default:
532 return 0;
533 }
534 }
535
536 #endif /* !__UBIFS_KEY_H__ */
537