lwext4/include/ext4_dir.h

/*
 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
 *
 *
 * HelenOS:
 * Copyright (c) 2012 Martin Sucha
 * Copyright (c) 2012 Frantisek Princ
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup lwext4
 * @{
 */
/**
 * @file  ext4_dir.h
 * @brief Directory handle procedures.
 */

#ifndef EXT4_DIR_H_
#define EXT4_DIR_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <ext4_config.h>
#include <ext4_types.h>
#include <ext4_misc.h>
#include <ext4_blockdev.h>
#include <ext4_super.h>

#include <stdint.h>

struct ext4_dir_iter {
    struct ext4_inode_ref *inode_ref;
    struct ext4_block curr_blk;
    uint64_t curr_off;
    struct ext4_dir_en *curr;
};

struct ext4_dir_search_result {
    struct ext4_block block;
    struct ext4_dir_en *dentry;
};


/**@brief Get i-node number from directory entry.
 * @param de Directory entry
 * @return I-node number
 */
static inline uint32_t
ext4_dir_en_get_inode(struct ext4_dir_en *de)
{
    return to_le32(de->inode);
}

/**@brief Set i-node number to directory entry.
 * @param de Directory entry
 * @param inode I-node number
 */
static inline void
ext4_dir_en_set_inode(struct ext4_dir_en *de, uint32_t inode)
{
    de->inode = to_le32(inode);
}

/**@brief Set i-node number to directory entry. (For HTree root)
 * @param de Directory entry
 * @param inode I-node number
 */
static inline void
ext4_dx_dot_en_set_inode(struct ext4_dir_idx_dot_en *de, uint32_t inode)
{
    de->inode = to_le32(inode);
}

/**@brief Get directory entry length.
 * @param de Directory entry
 * @return Entry length
 */
static inline uint16_t ext4_dir_en_get_entry_len(struct ext4_dir_en *de)
{
    return to_le16(de->entry_len);
}

/**@brief Set directory entry length.
 * @param de     Directory entry
 * @param l Entry length
 */
static inline void ext4_dir_en_set_entry_len(struct ext4_dir_en *de, uint16_t l)
{
    de->entry_len = to_le16(l);
}

/**@brief Get directory entry name length.
 * @param sb Superblock
 * @param de Directory entry
 * @return Entry name length
 */
static inline uint16_t ext4_dir_en_get_name_len(struct ext4_sblock *sb,
                        struct ext4_dir_en *de)
{
    uint16_t v = de->name_len;

    if ((ext4_get32(sb, rev_level) == 0) &&
        (ext4_get32(sb, minor_rev_level) < 5))
        v |= ((uint16_t)de->in.name_length_high) << 8;

    return v;
}

/**@brief Set directory entry name length.
 * @param sb     Superblock
 * @param de     Directory entry
 * @param len Entry name length
 */
static inline void ext4_dir_en_set_name_len(struct ext4_sblock *sb,
                        struct ext4_dir_en *de,
                        uint16_t len)
{
    de->name_len = (len << 8) >> 8;

    if ((ext4_get32(sb, rev_level) == 0) &&
        (ext4_get32(sb, minor_rev_level) < 5))
        de->in.name_length_high = len >> 8;
}

/**@brief Get i-node type of directory entry.
 * @param sb Superblock
 * @param de Directory entry
 * @return I-node type (file, dir, etc.)
 */
static inline uint8_t ext4_dir_en_get_inode_type(struct ext4_sblock *sb,
                         struct ext4_dir_en *de)
{
    if ((ext4_get32(sb, rev_level) > 0) ||
        (ext4_get32(sb, minor_rev_level) >= 5))
        return de->in.inode_type;

    return EXT4_DE_UNKNOWN;
}
/**@brief Set i-node type of directory entry.
 * @param sb   Superblock
 * @param de   Directory entry
 * @param t I-node type (file, dir, etc.)
 */

static inline void ext4_dir_en_set_inode_type(struct ext4_sblock *sb,
                          struct ext4_dir_en *de, uint8_t t)
{
    if ((ext4_get32(sb, rev_level) > 0) ||
        (ext4_get32(sb, minor_rev_level) >= 5))
        de->in.inode_type = t;
}

/**@brief Verify checksum of a linear directory leaf block
 * @param inode_ref Directory i-node
 * @param dirent    Linear directory leaf block
 * @return true means the block passed checksum verification
 */
bool ext4_dir_csum_verify(struct ext4_inode_ref *inode_ref,
              struct ext4_dir_en *dirent);

/**@brief Initialize directory iterator.
 * Set position to the first valid entry from the required position.
 * @param it        Pointer to iterator to be initialized
 * @param inode_ref Directory i-node
 * @param pos       Position to start reading entries from
 * @return Error code
 */
int ext4_dir_iterator_init(struct ext4_dir_iter *it,
               struct ext4_inode_ref *inode_ref, uint64_t pos);

/**@brief Jump to the next valid entry
 * @param it Initialized iterator
 * @return Error code
 */
int ext4_dir_iterator_next(struct ext4_dir_iter *it);

/**@brief Uninitialize directory iterator.
 *        Release all allocated structures.
 * @param it Iterator to be finished
 * @return Error code
 */
int ext4_dir_iterator_fini(struct ext4_dir_iter *it);

/**@brief Write directory entry to concrete data block.
 * @param sb        Superblock
 * @param en     Pointer to entry to be written
 * @param entry_len Length of new entry
 * @param child     Child i-node to be written to new entry
 * @param name      Name of the new entry
 * @param name_len  Length of entry name
 */
void ext4_dir_write_entry(struct ext4_sblock *sb, struct ext4_dir_en *en,
              uint16_t entry_len, struct ext4_inode_ref *child,
              const char *name, size_t name_len);

/**@brief Add new entry to the directory.
 * @param parent Directory i-node
 * @param name   Name of new entry
 * @param child  I-node to be referenced from new entry
 * @return Error code
 */
int ext4_dir_add_entry(struct ext4_inode_ref *parent, const char *name,
               uint32_t name_len, struct ext4_inode_ref *child);

/**@brief Find directory entry with passed name.
 * @param result Result structure to be returned if entry found
 * @param parent Directory i-node
 * @param name   Name of entry to be found
 * @param name_len  Name length
 * @return Error code
 */
int ext4_dir_find_entry(struct ext4_dir_search_result *result,
            struct ext4_inode_ref *parent, const char *name,
            uint32_t name_len);

/**@brief Remove directory entry.
 * @param parent Directory i-node
 * @param name   Name of the entry to be removed
 * @param name_len  Name length
 * @return Error code
 */
int ext4_dir_remove_entry(struct ext4_inode_ref *parent, const char *name,
              uint32_t name_len);

/**@brief Try to insert entry to concrete data block.
 * @param sb           Superblock
 * @param inode_ref    Directory i-node
 * @param dst_blk      Block to try to insert entry to
 * @param child        Child i-node to be inserted by new entry
 * @param name         Name of the new entry
 * @param name_len     Length of the new entry name
 * @return Error code
 */
int ext4_dir_try_insert_entry(struct ext4_sblock *sb,
                  struct ext4_inode_ref *inode_ref,
                  struct ext4_block *dst_blk,
                  struct ext4_inode_ref *child, const char *name,
                  uint32_t name_len);

/**@brief Try to find entry in block by name.
 * @param block     Block containing entries
 * @param sb        Superblock
 * @param name_len  Length of entry name
 * @param name      Name of entry to be found
 * @param res_entry Output pointer to found entry, NULL if not found
 * @return Error code
 */
int ext4_dir_find_in_block(struct ext4_block *block, struct ext4_sblock *sb,
               size_t name_len, const char *name,
               struct ext4_dir_en **res_entry);

/**@brief Simple function to release allocated data from result.
 * @param parent Parent inode
 * @param result Search result to destroy
 * @return Error code
 *
 */
int ext4_dir_destroy_result(struct ext4_inode_ref *parent,
                struct ext4_dir_search_result *result);

void ext4_dir_set_csum(struct ext4_inode_ref *inode_ref,
               struct ext4_dir_en *dirent);


void ext4_dir_init_entry_tail(struct ext4_dir_entry_tail *t);

#ifdef __cplusplus
}
#endif

#endif /* EXT4_DIR_H_ */

/**
 * @}
 */