linux/fs/ubifs/key.h

/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * key_test_hash - testing hash function.
 * @str: direntry name
 * @len: name length
 */
static inline uint32_t key_test_hash(const char *str, int len)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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. Not a string when encrypted!
 */
static inline void dent_key_init(const struct ubifs_info *c,
				 union ubifs_key *key, ino_t inum,
				 const struct fscrypt_name *nm)
{ … }

/**
 * 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)
{ … }

/**
 * 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 fscrypt_name *nm)
{ … }

/**
 * 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)
{ … }

/**
 * 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 fscrypt_name *nm)
{ … }

/**
 * 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 fscrypt_name *nm)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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_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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

/**
 * 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)
{ … }

#endif /* !__UBIFS_KEY_H__ */