diff options
Diffstat (limited to 'include/sqfs/inode.h')
| -rw-r--r-- | include/sqfs/inode.h | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/include/sqfs/inode.h b/include/sqfs/inode.h index d0c49a1..0019360 100644 --- a/include/sqfs/inode.h +++ b/include/sqfs/inode.h @@ -22,6 +22,17 @@ #include "sqfs/predef.h" +/** + * @file inode.h + * + * @brief Contains on-disk data structures used for inodes. + */ + +/** + * @enum E_SQFS_INODE_TYPE + * + * @brief Used by @ref sqfs_inode_t to identify the inode type. + */ typedef enum { SQFS_INODE_DIR = 1, SQFS_INODE_FILE = 2, @@ -39,91 +50,389 @@ typedef enum { SQFS_INODE_EXT_SOCKET = 14, } E_SQFS_INODE_TYPE; +/** + * @struct sqfs_inode_t + * + * @brief Common inode structure + * + * This structure holds the fields common for all inodes. Depending on the type + * field, a specific inode structure follows. + */ struct sqfs_inode_t { + /** + * @brief An @ref E_SQFS_INODE_TYPE value. + */ uint16_t type; + + /** + * @brief Mode filed holding permission bits only. The type is derived + * from the type field. + */ uint16_t mode; + + /** + * @brief An index into the ID table where the owner UID is located. + */ uint16_t uid_idx; + + /** + * @brief An index into the ID table where the owner GID is located. + */ uint16_t gid_idx; + + /** + * @brief Last modifcation time. + * + * This field counts seconds (not counting leap seconds) since 00:00, + * Jan 1 1970 UTC. This field is unsigned, so it expires in the year + * 2106 (as opposed to 2038). + */ uint32_t mod_time; + + /** + * @brief Unique inode number + */ uint32_t inode_number; }; +/** + * @struct sqfs_inode_dev_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_BDEV + * or @ref SQFS_INODE_CDEV. + */ struct sqfs_inode_dev_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Device number. + */ uint32_t devno; }; +/** + * @struct sqfs_inode_dev_ext_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_EXT_BDEV + * or @ref SQFS_INODE_EXT_CDEV. + */ struct sqfs_inode_dev_ext_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Device number. + */ uint32_t devno; + + /** + * @brief Extended attribute index. + */ uint32_t xattr_idx; }; +/** + * @struct sqfs_inode_ipc_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_FIFO + * or @ref SQFS_INODE_SOCKET. + */ struct sqfs_inode_ipc_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; }; +/** + * @struct sqfs_inode_ipc_ext_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_EXT_FIFO + * or @ref SQFS_INODE_EXT_SOCKET. + */ struct sqfs_inode_ipc_ext_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Extended attribute index. + */ uint32_t xattr_idx; }; +/** + * @struct sqfs_inode_slink_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_SLINK. + * + * The declaration does not contain the flexible array member of the symlink + * target because @ref sqfs_inode_generic_t would otherwies be impossible to + * implement without violating the C standard. + */ struct sqfs_inode_slink_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Size of the symlink target in bytes + */ uint32_t target_size; + /*uint8_t target[];*/ }; +/** + * @struct sqfs_inode_slink_ext_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_EXT_SLINK. + * + * The declaration does not contain the flexible array member of the symlink + * target because it is wedged right in between the target size and the xattr + * identifier. + */ struct sqfs_inode_slink_ext_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Size of the symlink target in bytes + */ uint32_t target_size; + /*uint8_t target[];*/ + + /** + * @brief Extended attribute index. + */ uint32_t xattr_idx; }; +/** + * @struct sqfs_inode_file_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_FILE. + * + * The declaration does not contain the flexible array member for the data + * block sizes because @ref sqfs_inode_generic_t would otherwies be impossible + * to implement without violating the C standard. + * + * For each data block, the inode is followed by a 32 bit integer that holds + * the on-disk size of the compressed block in bytes and has bit number 24 + * set if the block is stored uncompressed. + * + * If a block size is specified as zero, it is assumed to be an entire block + * filled with zero bytes. + */ struct sqfs_inode_file_t { + /** + * @brief Absolute position of the first data block. + */ uint32_t blocks_start; + + /** + * @brief Index into the fragment table or 0xFFFFFFFF if unused. + */ uint32_t fragment_index; + + /** + * @brief Offset into the uncompressed fragment block or 0xFFFFFFFF + * if unused. + */ uint32_t fragment_offset; + + /** + * @brief Total, uncompressed size of the file in bytes. + */ uint32_t file_size; + /*uint32_t block_sizes[];*/ }; +/** + * @struct sqfs_inode_file_ext_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_EXT_FILE. + * + * @copydoc sqfs_inode_file_t + */ struct sqfs_inode_file_ext_t { + /** + * @brief Absolute position of the first data block. + */ uint64_t blocks_start; + + /** + * @brief Total, uncompressed size of the file in bytes. + */ uint64_t file_size; + + /** + * @brief If the file is sparse, holds the number of bytes not written + * to disk because of the omitted sparse blocks. + */ uint64_t sparse; + + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Index into the fragment table or 0xFFFFFFFF if unused. + */ uint32_t fragment_idx; + + /** + * @brief Offset into the uncompressed fragment block or 0xFFFFFFFF + * if unused. + */ uint32_t fragment_offset; + + /** + * @brief Extended attribute index. + */ uint32_t xattr_idx; + /*uint32_t block_sizes[];*/ }; +/** + * @struct sqfs_inode_dir_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_DIR. + */ struct sqfs_inode_dir_t { + /** + * @brief Offset from the directory table start to the location of the + * meta data block containing the first directory header. + */ uint32_t start_block; + + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Combined size of all directory entries and headers in bytes. + */ uint16_t size; + + /** + * @brief Offset into the uncompressed start block where the header can + * be found. + */ uint16_t offset; + + /** + * @brief Inode number of the parent directory containing + * this directory inode. + */ uint32_t parent_inode; }; +/** + * @struct sqfs_inode_dir_ext_t + * + * @brief Follows a @ref sqfs_inode_t if type is @ref SQFS_INODE_EXT_DIR. + */ struct sqfs_inode_dir_ext_t { + /** + * @brief Number of hard links to this node. + */ uint32_t nlink; + + /** + * @brief Combined size of all directory entries and headers in bytes. + */ uint32_t size; + + /** + * @brief Offset from the directory table start to the location of the + * meta data block containing the first directory header. + */ uint32_t start_block; + + /** + * @brief Inode number of the parent directory containing + * this directory inode. + */ uint32_t parent_inode; + + /** + * @brief Number of directory index entries following the inode + * + * This number is stored off-by one and counts the number of + * @ref sqfs_dir_index_t entries following the inode. + */ uint16_t inodex_count; + + /** + * @brief Offset into the uncompressed start block where the header can + * be found. + */ uint16_t offset; + + /** + * @brief Extended attribute index. + */ uint32_t xattr_idx; }; +/** + * @struct sqfs_inode_generic_t + * + * @brief A generic inode structure that combines all others and provides + * additional information. + * + * A few helper functions exist for working with this. For instance, + * @ref sqfs_meta_reader_read_inode can read an inode from disk and assemble it + * into an instance of this structure. Similarly, the + * @ref sqfs_meta_writer_write_inode function can break it down into encoded, + * on-disk structures and write them to disk. + */ struct sqfs_inode_generic_t { + /** + * @brief The common fields for all inodes. + */ sqfs_inode_t base; + + /** + * @brief A pointer into the extra field holding the symlink target. + * + * @param This string is not null terminated. The helper functions rely + * entirely on the length stored in the symlink inode. + */ char *slink_target; + + /** + * @brief A pointer into the extra field holding file blocks sizes. + * + * For file inodes, holds the consecutive block sizes. Bit number 24 is + * set if the block is stored uncompressed. If it the size is zero, + * the block is sparse. + */ uint32_t *block_sizes; + + /** + * @brief For file inodes, stores the number of blocks used. + */ size_t num_file_blocks; + /** + * @brief Type specific inode data. + */ union { sqfs_inode_dev_t dev; sqfs_inode_dev_ext_t dev_ext; @@ -137,6 +446,9 @@ struct sqfs_inode_generic_t { sqfs_inode_dir_ext_t dir_ext; } data; + /** + * @brief Holds type specific extra data, such as symlink target. + */ uint8_t extra[]; }; |