xref: /openbmc/u-boot/fs/ubifs/key.h (revision ef64e782) 
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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  */
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