xref: /openbmc/u-boot/fs/ubifs/key.h (revision 1e52fea3) 
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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_hash - initialize extended attribute entry key without
233  *                      re-calculating hash function.
234  * @c: UBIFS file-system description object
235  * @key: key to initialize
236  * @inum: host inode number
237  * @hash: extended attribute entry name hash
238  */
239 static inline void xent_key_init_hash(const struct ubifs_info *c,
240 				      union ubifs_key *key, ino_t inum,
241 				      uint32_t hash)
242 {
243 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
244 	key->u32[0] = inum;
245 	key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
246 }
247 
248 /**
249  * xent_key_init_flash - initialize on-flash extended attribute entry key.
250  * @c: UBIFS file-system description object
251  * @k: key to initialize
252  * @inum: host inode number
253  * @nm: extended attribute entry name and length
254  */
255 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
256 				       ino_t inum, const struct qstr *nm)
257 {
258 	union ubifs_key *key = k;
259 	uint32_t hash = c->key_hash(nm->name, nm->len);
260 
261 	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
262 	key->j32[0] = cpu_to_le32(inum);
263 	key->j32[1] = cpu_to_le32(hash |
264 				  (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
265 	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
266 }
267 
268 /**
269  * lowest_xent_key - get the lowest possible extended attribute entry key.
270  * @c: UBIFS file-system description object
271  * @key: where to store the lowest key
272  * @inum: host inode number
273  */
274 static inline void lowest_xent_key(const struct ubifs_info *c,
275 				   union ubifs_key *key, ino_t inum)
276 {
277 	key->u32[0] = inum;
278 	key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
279 }
280 
281 /**
282  * data_key_init - initialize data key.
283  * @c: UBIFS file-system description object
284  * @key: key to initialize
285  * @inum: inode number
286  * @block: block number
287  */
288 static inline void data_key_init(const struct ubifs_info *c,
289 				 union ubifs_key *key, ino_t inum,
290 				 unsigned int block)
291 {
292 	ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
293 	key->u32[0] = inum;
294 	key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
295 }
296 
297 /**
298  * data_key_init_flash - initialize on-flash data key.
299  * @c: UBIFS file-system description object
300  * @k: key to initialize
301  * @inum: inode number
302  * @block: block number
303  */
304 static inline void data_key_init_flash(const struct ubifs_info *c, void *k,
305 				       ino_t inum, unsigned int block)
306 {
307 	union ubifs_key *key = k;
308 
309 	ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
310 	key->j32[0] = cpu_to_le32(inum);
311 	key->j32[1] = cpu_to_le32(block |
312 				  (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS));
313 	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
314 }
315 
316 /**
317  * trun_key_init - initialize truncation node key.
318  * @c: UBIFS file-system description object
319  * @key: key to initialize
320  * @inum: inode number
321  *
322  * Note, UBIFS does not have truncation keys on the media and this function is
323  * only used for purposes of replay.
324  */
325 static inline void trun_key_init(const struct ubifs_info *c,
326 				 union ubifs_key *key, ino_t inum)
327 {
328 	key->u32[0] = inum;
329 	key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
330 }
331 
332 /**
333  * key_type - get key type.
334  * @c: UBIFS file-system description object
335  * @key: key to get type of
336  */
337 static inline int key_type(const struct ubifs_info *c,
338 			   const union ubifs_key *key)
339 {
340 	return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
341 }
342 
343 /**
344  * key_type_flash - get type of a on-flash formatted key.
345  * @c: UBIFS file-system description object
346  * @k: key to get type of
347  */
348 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
349 {
350 	const union ubifs_key *key = k;
351 
352 	return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
353 }
354 
355 /**
356  * key_inum - fetch inode number from key.
357  * @c: UBIFS file-system description object
358  * @k: key to fetch inode number from
359  */
360 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
361 {
362 	const union ubifs_key *key = k;
363 
364 	return key->u32[0];
365 }
366 
367 /**
368  * key_inum_flash - fetch inode number from an on-flash formatted key.
369  * @c: UBIFS file-system description object
370  * @k: key to fetch inode number from
371  */
372 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
373 {
374 	const union ubifs_key *key = k;
375 
376 	return le32_to_cpu(key->j32[0]);
377 }
378 
379 /**
380  * key_hash - get directory entry hash.
381  * @c: UBIFS file-system description object
382  * @key: the key to get hash from
383  */
384 static inline int key_hash(const struct ubifs_info *c,
385 			   const union ubifs_key *key)
386 {
387 	return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
388 }
389 
390 /**
391  * key_hash_flash - get directory entry hash from an on-flash formatted key.
392  * @c: UBIFS file-system description object
393  * @k: the key to get hash from
394  */
395 static inline int key_hash_flash(const struct ubifs_info *c, const void *k)
396 {
397 	const union ubifs_key *key = k;
398 
399 	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
400 }
401 
402 /**
403  * key_block - get data block number.
404  * @c: UBIFS file-system description object
405  * @key: the key to get the block number from
406  */
407 static inline unsigned int key_block(const struct ubifs_info *c,
408 				     const union ubifs_key *key)
409 {
410 	return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
411 }
412 
413 /**
414  * key_block_flash - get data block number from an on-flash formatted key.
415  * @c: UBIFS file-system description object
416  * @k: the key to get the block number from
417  */
418 static inline unsigned int key_block_flash(const struct ubifs_info *c,
419 					   const void *k)
420 {
421 	const union ubifs_key *key = k;
422 
423 	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
424 }
425 
426 /**
427  * key_read - transform a key to in-memory format.
428  * @c: UBIFS file-system description object
429  * @from: the key to transform
430  * @to: the key to store the result
431  */
432 static inline void key_read(const struct ubifs_info *c, const void *from,
433 			    union ubifs_key *to)
434 {
435 	const union ubifs_key *f = from;
436 
437 	to->u32[0] = le32_to_cpu(f->j32[0]);
438 	to->u32[1] = le32_to_cpu(f->j32[1]);
439 }
440 
441 /**
442  * key_write - transform a key from in-memory format.
443  * @c: UBIFS file-system description object
444  * @from: the key to transform
445  * @to: the key to store the result
446  */
447 static inline void key_write(const struct ubifs_info *c,
448 			     const union ubifs_key *from, void *to)
449 {
450 	union ubifs_key *t = to;
451 
452 	t->j32[0] = cpu_to_le32(from->u32[0]);
453 	t->j32[1] = cpu_to_le32(from->u32[1]);
454 	memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
455 }
456 
457 /**
458  * key_write_idx - transform a key from in-memory format for the index.
459  * @c: UBIFS file-system description object
460  * @from: the key to transform
461  * @to: the key to store the result
462  */
463 static inline void key_write_idx(const struct ubifs_info *c,
464 				 const union ubifs_key *from, void *to)
465 {
466 	union ubifs_key *t = to;
467 
468 	t->j32[0] = cpu_to_le32(from->u32[0]);
469 	t->j32[1] = cpu_to_le32(from->u32[1]);
470 }
471 
472 /**
473  * key_copy - copy a key.
474  * @c: UBIFS file-system description object
475  * @from: the key to copy from
476  * @to: the key to copy to
477  */
478 static inline void key_copy(const struct ubifs_info *c,
479 			    const union ubifs_key *from, union ubifs_key *to)
480 {
481 	to->u64[0] = from->u64[0];
482 }
483 
484 /**
485  * keys_cmp - compare keys.
486  * @c: UBIFS file-system description object
487  * @key1: the first key to compare
488  * @key2: the second key to compare
489  *
490  * This function compares 2 keys and returns %-1 if @key1 is less than
491  * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
492  */
493 static inline int keys_cmp(const struct ubifs_info *c,
494 			   const union ubifs_key *key1,
495 			   const union ubifs_key *key2)
496 {
497 	if (key1->u32[0] < key2->u32[0])
498 		return -1;
499 	if (key1->u32[0] > key2->u32[0])
500 		return 1;
501 	if (key1->u32[1] < key2->u32[1])
502 		return -1;
503 	if (key1->u32[1] > key2->u32[1])
504 		return 1;
505 
506 	return 0;
507 }
508 
509 /**
510  * keys_eq - determine if keys are equivalent.
511  * @c: UBIFS file-system description object
512  * @key1: the first key to compare
513  * @key2: the second key to compare
514  *
515  * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
516  * %0 if not.
517  */
518 static inline int keys_eq(const struct ubifs_info *c,
519 			  const union ubifs_key *key1,
520 			  const union ubifs_key *key2)
521 {
522 	if (key1->u32[0] != key2->u32[0])
523 		return 0;
524 	if (key1->u32[1] != key2->u32[1])
525 		return 0;
526 	return 1;
527 }
528 
529 /**
530  * is_hash_key - is a key vulnerable to hash collisions.
531  * @c: UBIFS file-system description object
532  * @key: key
533  *
534  * This function returns %1 if @key is a hashed key or %0 otherwise.
535  */
536 static inline int is_hash_key(const struct ubifs_info *c,
537 			      const union ubifs_key *key)
538 {
539 	int type = key_type(c, key);
540 
541 	return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
542 }
543 
544 /**
545  * key_max_inode_size - get maximum file size allowed by current key format.
546  * @c: UBIFS file-system description object
547  */
548 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
549 {
550 	switch (c->key_fmt) {
551 	case UBIFS_SIMPLE_KEY_FMT:
552 		return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
553 	default:
554 		return 0;
555 	}
556 }
557 #endif /* !__UBIFS_KEY_H__ */
558