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