/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Artem Bityutskiy (Битюцкий Артём)
* Adrian Hunter
*/
/*
* This header contains various key-related definitions and helper function.
* UBIFS allows several key schemes, so we access key fields only via these
* helpers. At the moment only one key scheme is supported.
*
* Simple key scheme
* ~~~~~~~~~~~~~~~~~
*
* Keys are 64-bits long. First 32-bits are inode number (parent inode number
* in case of direntry key). Next 3 bits are node type. The last 29 bits are
* 4KiB offset in case of inode node, and direntry hash in case of a direntry
* node. We use "r5" hash borrowed from reiserfs.
*/
/*
* Lot's of the key helpers require a struct ubifs_info *c as the first parameter.
* But we are not using it at all currently. That's designed for future extensions of
* different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.
*/
#ifndef __UBIFS_KEY_H__
#define __UBIFS_KEY_H__
/**
* key_mask_hash - mask a valid hash value.
* @val: value to be masked
*
* We use hash values as offset in directories, so values %0 and %1 are
* reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
* function makes sure the reserved values are not used.
*/
static inline uint32_t key_mask_hash(uint32_t hash)
{
hash &= UBIFS_S_KEY_HASH_MASK;
if (unlikely(hash <= 2))
hash += 3;
return hash;
}
/**
* key_r5_hash - R5 hash function (borrowed from reiserfs).
* @s: direntry name
* @len: name length
*/
static inline uint32_t key_r5_hash(const char *s, int len)
{
uint32_t a = 0;
const signed char *str = (const signed char *)s;
while (*str) {
a += *str << 4;
a += *str >> 4;
a *= 11;
str++;
}
return key_mask_hash(a);
}
/**
* key_test_hash - testing hash function.
* @str: direntry name
* @len: name length
*/
static inline uint32_t key_test_hash(const char *str, int len)
{
uint32_t a = 0;
len = min_t(uint32_t, len, 4);
memcpy(&a, str, len);
return key_mask_hash(a);
}
/**
* ino_key_init - initialize inode key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
*/
static inline void ino_key_init(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
}
/**
* ino_key_init_flash - initialize on-flash inode key.
* @c: UBIFS file-system description object
* @k: key to initialize
* @inum: inode number
*/
static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
ino_t inum)
{
union ubifs_key *key = k;
key->j32[0] = cpu_to_le32(inum);
key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}
/**
* lowest_ino_key - get the lowest possible inode key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
*/
static inline void lowest_ino_key(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = 0;
}
/**
* highest_ino_key - get the highest possible inode key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
*/
static inline void highest_ino_key(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = 0xffffffff;
}
/**
* dent_key_init - initialize directory entry key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: parent inode number
* @nm: direntry name and length
*/
static inline void dent_key_init(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum,
const struct qstr *nm)
{
uint32_t hash = c->key_hash(nm->name, nm->len);
ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
key->u32[0] = inum;
key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
}
/**
* dent_key_init_hash - initialize directory entry key without re-calculating
* hash function.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: parent inode number
* @hash: direntry name hash
*/
static inline void dent_key_init_hash(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum,
uint32_t hash)
{
ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
key->u32[0] = inum;
key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
}
/**
* dent_key_init_flash - initialize on-flash directory entry key.
* @c: UBIFS file-system description object
* @k: key to initialize
* @inum: parent inode number
* @nm: direntry name and length
*/
static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
ino_t inum, const struct qstr *nm)
{
union ubifs_key *key = k;
uint32_t hash = c->key_hash(nm->name, nm->len);
ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
key->j32[0] = cpu_to_le32(inum);
key->j32[1] = cpu_to_le32(hash |
(UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}
/**
* lowest_dent_key - get the lowest possible directory entry key.
* @c: UBIFS file-system description object
* @key: where to store the lowest key
* @inum: parent inode number
*/
static inline void lowest_dent_key(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
}
/**
* xent_key_init - initialize extended attribute entry key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: host inode number
* @nm: extended attribute entry name and length
*/
static inline void xent_key_init(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum,
const struct qstr *nm)
{
uint32_t hash = c->key_hash(nm->name, nm->len);
ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
key->u32[0] = inum;
key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
}
/**
* xent_key_init_flash - initialize on-flash extended attribute entry key.
* @c: UBIFS file-system description object
* @k: key to initialize
* @inum: host inode number
* @nm: extended attribute entry name and length
*/
static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
ino_t inum, const struct qstr *nm)
{
union ubifs_key *key = k;
uint32_t hash = c->key_hash(nm->name, nm->len);
ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
key->j32[0] = cpu_to_le32(inum);
key->j32[1] = cpu_to_le32(hash |
(UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}
/**
* lowest_xent_key - get the lowest possible extended attribute entry key.
* @c: UBIFS file-system description object
* @key: where to store the lowest key
* @inum: host inode number
*/
static inline void lowest_xent_key(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
}
/**
* data_key_init - initialize data key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
* @block: block number
*/
static inline void data_key_init(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum,
unsigned int block)
{
ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
key->u32[0] = inum;
key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
}
/**
* highest_data_key - get the highest possible data key for an inode.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
*/
static inline void highest_data_key(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
}
/**
* trun_key_init - initialize truncation node key.
* @c: UBIFS file-system description object
* @key: key to initialize
* @inum: inode number
*
* Note, UBIFS does not have truncation keys on the media and this function is
* only used for purposes of replay.
*/
static inline void trun_key_init(const struct ubifs_info *c,
union ubifs_key *key, ino_t inum)
{
key->u32[0] = inum;
key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
}
/**
* invalid_key_init - initialize invalid node key.
* @c: UBIFS file-system description object
* @key: key to initialize
*
* This is a helper function which marks a @key object as invalid.
*/
static inline void invalid_key_init(const struct ubifs_info *c,
union ubifs_key *key)
{
key->u32[0] = 0xDEADBEAF;
key->u32[1] = UBIFS_INVALID_KEY;
}
/**
* key_type - get key type.
* @c: UBIFS file-system description object
* @key: key to get type of
*/
static inline int key_type(const struct ubifs_info *c,
const union ubifs_key *key)
{
return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
}
/**
* key_type_flash - get type of a on-flash formatted key.
* @c: UBIFS file-system description object
* @k: key to get type of
*/
static inline int key_type_flash(const struct ubifs_info *c, const void *k)
{
const union ubifs_key *key = k;
return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
}
/**
* key_inum - fetch inode number from key.
* @c: UBIFS file-system description object
* @k: key to fetch inode number from
*/
static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
{
const union ubifs_key *key = k;
return key->u32[0];
}
/**
* key_inum_flash - fetch inode number from an on-flash formatted key.
* @c: UBIFS file-system description object
* @k: key to fetch inode number from
*/
static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
{
const union ubifs_key *key = k;
return le32_to_cpu(key->j32[0]);
}
/**
* key_hash - get directory entry hash.
* @c: UBIFS file-system description object
* @key: the key to get hash from
*/
static inline uint32_t key_hash(const struct ubifs_info *c,
const union ubifs_key *key)
{
return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
}
/**
* key_hash_flash - get directory entry hash from an on-flash formatted key.
* @c: UBIFS file-system description object
* @k: the key to get hash from
*/
static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
{
const union ubifs_key *key = k;
return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
}
/**
* key_block - get data block number.
* @c: UBIFS file-system description object
* @key: the key to get the block number from
*/
static inline unsigned int key_block(const struct ubifs_info *c,
const union ubifs_key *key)
{
return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
}
/**
* key_block_flash - get data block number from an on-flash formatted key.
* @c: UBIFS file-system description object
* @k: the key to get the block number from
*/
static inline unsigned int key_block_flash(const struct ubifs_info *c,
const void *k)
{
const union ubifs_key *key = k;
return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
}
/**
* key_read - transform a key to in-memory format.
* @c: UBIFS file-system description object
* @from: the key to transform
* @to: the key to store the result
*/
static inline void key_read(const struct ubifs_info *c, const void *from,
union ubifs_key *to)
{
const union ubifs_key *f = from;
to->u32[0] = le32_to_cpu(f->j32[0]);
to->u32[1] = le32_to_cpu(f->j32[1]);
}
/**
* key_write - transform a key from in-memory format.
* @c: UBIFS file-system description object
* @from: the key to transform
* @to: the key to store the result
*/
static inline void key_write(const struct ubifs_info *c,
const union ubifs_key *from, void *to)
{
union ubifs_key *t = to;
t->j32[0] = cpu_to_le32(from->u32[0]);
t->j32[1] = cpu_to_le32(from->u32[1]);
memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}
/**
* key_write_idx - transform a key from in-memory format for the index.
* @c: UBIFS file-system description object
* @from: the key to transform
* @to: the key to store the result
*/
static inline void key_write_idx(const struct ubifs_info *c,
const union ubifs_key *from, void *to)
{
union ubifs_key *t = to;
t->j32[0] = cpu_to_le32(from->u32[0]);
t->j32[1] = cpu_to_le32(from->u32[1]);
}
/**
* key_copy - copy a key.
* @c: UBIFS file-system description object
* @from: the key to copy from
* @to: the key to copy to
*/
static inline void key_copy(const struct ubifs_info *c,
const union ubifs_key *from, union ubifs_key *to)
{
to->u64[0] = from->u64[0];
}
/**
* keys_cmp - compare keys.
* @c: UBIFS file-system description object
* @key1: the first key to compare
* @key2: the second key to compare
*
* This function compares 2 keys and returns %-1 if @key1 is less than
* @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
*/
static inline int keys_cmp(const struct ubifs_info *c,
const union ubifs_key *key1,
const union ubifs_key *key2)
{
if (key1->u32[0] < key2->u32[0])
return -1;
if (key1->u32[0] > key2->u32[0])
return 1;
if (key1->u32[1] < key2->u32[1])
return -1;
if (key1->u32[1] > key2->u32[1])
return 1;
return 0;
}
/**
* keys_eq - determine if keys are equivalent.
* @c: UBIFS file-system description object
* @key1: the first key to compare
* @key2: the second key to compare
*
* This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
* %0 if not.
*/
static inline int keys_eq(const struct ubifs_info *c,
const union ubifs_key *key1,
const union ubifs_key *key2)
{
if (key1->u32[0] != key2->u32[0])
return 0;
if (key1->u32[1] != key2->u32[1])
return 0;
return 1;
}
/**
* is_hash_key - is a key vulnerable to hash collisions.
* @c: UBIFS file-system description object
* @key: key
*
* This function returns %1 if @key is a hashed key or %0 otherwise.
*/
static inline int is_hash_key(const struct ubifs_info *c,
const union ubifs_key *key)
{
int type = key_type(c, key);
return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
}
/**
* key_max_inode_size - get maximum file size allowed by current key format.
* @c: UBIFS file-system description object
*/
static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
{
switch (c->key_fmt) {
case UBIFS_SIMPLE_KEY_FMT:
return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
default:
return 0;
}
}
#endif /* !__UBIFS_KEY_H__ */
