#pragma once #include #include #define EXT2_SUPERBLOCK_OFFSET 1024 #define EXT2_SUPERBLOCK_SIZE 1024 #define EXT2_MAGIC 0xEF53 #define EXT2_NAME_LEN 255 typedef struct ext2_superblock { unsigned int s_inodes_count; /* Inodes count */ unsigned int s_blocks_count; /* Blocks count */ unsigned int s_r_blocks_count; /* Reserved blocks count */ unsigned int s_free_blocks_count; /* Free blocks count */ unsigned int s_free_inodes_count; /* Free inodes count */ unsigned int s_first_data_block; /* First Data Block */ unsigned int s_log_block_size; /* Block size */ unsigned int s_log_frag_size; /* Fragment size */ unsigned int s_blocks_per_group; /* # Blocks per group */ unsigned int s_frags_per_group; /* # Fragments per group */ unsigned int s_inodes_per_group; /* # Inodes per group */ unsigned int s_mtime; /* Mount time */ unsigned int s_wtime; /* Write time */ unsigned short s_mnt_count; /* Mount count */ unsigned short s_max_mnt_count; /* Maximal mount count */ unsigned short s_magic; /* Magic signature */ unsigned short s_state; /* File system state */ unsigned short s_errors; /* Behaviour when detecting errors */ unsigned short s_minor_rev_level; /* minor revision level */ unsigned int s_lastcheck; /* time of last check */ unsigned int s_checkinterval; /* max. time between checks */ unsigned int s_creator_os; /* OS */ unsigned int s_rev_level; /* Revision level */ unsigned short s_def_resuid; /* Default uid for reserved blocks */ unsigned short s_def_resgid; /* Default gid for reserved blocks */ /* * These fields are for EXT2_DYNAMIC_REV superblocks only. * * Note: the difference between the compatible feature set and * the incompatible feature set is that if there is a bit set * in the incompatible feature set that the kernel doesn't * know about, it should refuse to mount the filesystem. * * e2fsck's requirements are more strict; if it doesn't know * about a feature in either the compatible or incompatible * feature set, it must abort and not try to meddle with * things it doesn't understand... */ unsigned int s_first_ino; /* First non-reserved inode */ unsigned short s_inode_size; /* size of inode structure */ unsigned short s_block_group_nr; /* block group # of this superblock */ unsigned int s_feature_compat; /* compatible feature set */ unsigned int s_feature_incompat; /* incompatible feature set */ unsigned int s_feature_ro_compat; /* readonly-compatible feature set */ unsigned char s_uuid[16]; /* 128-bit uuid for volume */ char s_volume_name[16]; /* volume name */ char s_last_mounted[64]; /* directory where last mounted */ unsigned int s_algorithm_usage_bitmap; /* For compression */ /* * Performance hints. Directory preallocation should only * happen if the EXT2_COMPAT_PREALLOC flag is on. */ unsigned char s_prealloc_blocks; /* Nr of blocks to try to preallocate*/ unsigned char s_prealloc_dir_blocks; /* Nr to preallocate for dirs */ unsigned short s_padding1; /* * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set. */ unsigned char s_journal_uuid[16]; /* uuid of journal superblock */ unsigned int s_journal_inum; /* inode number of journal file */ unsigned int s_journal_dev; /* device number of journal file */ unsigned int s_last_orphan; /* start of list of inodes to delete */ unsigned int s_hash_seed[4]; /* HTREE hash seed */ unsigned char s_def_hash_version; /* Default hash version to use */ unsigned char s_reserved_char_pad; unsigned short s_reserved_word_pad; unsigned int s_default_mount_opts; unsigned int s_first_meta_bg; /* First metablock block group */ unsigned int s_reserved[190]; /* Padding to the end of the block */ } __attribute__((packed)) ext2_superblock_t; typedef struct ext2_group_desc { unsigned int bg_block_bitmap; /* Blocks bitmap block */ unsigned int bg_inode_bitmap; /* Inodes bitmap block */ unsigned int bg_inode_table; /* Inodes table block */ unsigned short bg_free_blocks_count; /* Free blocks count */ unsigned short bg_free_inodes_count; /* Free inodes count */ unsigned short bg_used_dirs_count; /* Directories count */ unsigned short bg_pad; unsigned int bg_reserved[3]; } __attribute__((packed)) ext2_group_desc_t; typedef struct ext2_inode { unsigned short i_mode; /* File mode */ unsigned short i_uid; /* Low 16 bits of Owner Uid */ unsigned int i_size; /* Size in bytes */ unsigned int i_atime; /* Access time */ unsigned int i_ctime; /* Creation time */ unsigned int i_mtime; /* Modification time */ unsigned int i_dtime; /* Deletion Time */ unsigned short i_gid; /* Low 16 bits of Group Id */ unsigned short i_links_count; /* Links count */ unsigned int i_blocks; /* Blocks count IN DISK SECTORS*/ unsigned int i_flags; /* File flags */ unsigned int osd1; /* OS dependent 1 */ unsigned int i_block[15]; /* Pointers to blocks */ unsigned int i_generation; /* File version (for NFS) */ unsigned int i_file_acl; /* File ACL */ unsigned int i_dir_acl; /* Directory ACL */ unsigned int i_faddr; /* Fragment address */ unsigned int extra[3]; } __attribute__((packed)) ext2_inode_t; typedef struct ext2_dir_entry { unsigned int inode; /* Inode number */ unsigned short rec_len; /* Directory entry length */ unsigned char name_len; /* Name length */ unsigned char file_type; char name[]; /* File name, up to EXT2_NAME_LEN */ } __attribute__((packed)) ext2_dir_entry_t; typedef struct { uint32_t ino; uint16_t mode; uint16_t uid; uint16_t gid; uint32_t size; uint32_t atime; uint32_t mtime; uint32_t ctime; uint32_t nlink; uint32_t blocks; } ext2_stat_t; typedef enum { EXT2_WRITE_OVERWRITE, EXT2_WRITE_APPEND, } ext2_write_mode_t; // Inode type and permissions #define EXT2_S_IFIFO 0x1000 #define EXT2_S_IFCHR 0x2000 #define EXT2_S_IFDIR 0x4000 #define EXT2_S_IFBLK 0x6000 #define EXT2_S_IFREG 0x8000 #define EXT2_S_IFLNK 0xA000 #define EXT2_S_IFSOCK 0xC000 #define EXT2_S_IRUSR 0x0100 #define EXT2_S_IWUSR 0x0080 #define EXT2_S_IXUSR 0x0040 #define EXT2_S_IRGRP 0x0020 #define EXT2_S_IWGRP 0x0010 #define EXT2_S_IXGRP 0x0008 #define EXT2_S_IROTH 0x0004 #define EXT2_S_IWOTH 0x0002 #define EXT2_S_IXOTH 0x0001 // File types for directory entries #define EXT2_FT_UNKNOWN 0 #define EXT2_FT_REG_FILE 1 #define EXT2_FT_DIR 2 #define EXT2_FT_CHRDEV 3 #define EXT2_FT_BLKDEV 4 #define EXT2_FT_FIFO 5 #define EXT2_FT_SOCK 6 #define EXT2_FT_SYMLINK 7 // ── init ────────────────────────────────────────────────────────────────────── bool ext2_read_superblock(void); bool ext2_read_group_desc_table(void); // ── low-level ──────────────────────────────────────────────────────────────── bool ext2_read_block(uint32_t block_num, void* buf); bool ext2_write_block(uint32_t block_num, const void* buf); bool ext2_read_inode(uint32_t inode_num, ext2_inode_t* out); bool ext2_write_inode(uint32_t inode_num, ext2_inode_t* inode); // ── path / directory ───────────────────────────────────────────────────────── uint32_t ext2_resolve_path(const char* path); // returns inode num, 0 = not found bool ext2_find_in_dir(ext2_inode_t* dir, const char* name, uint32_t* out_inum); bool ext2_read_dir(ext2_inode_t* dir); bool ext2_read_root_dir(void); // ── file I/O ───────────────────────────────────────────────────────────────── bool ext2_read_file(ext2_inode_t* inode, uint8_t* buf); bool ext2_write_file(ext2_inode_t* inode, uint32_t inode_num, const uint8_t* data, uint32_t size, ext2_write_mode_t mode); bool ext2_truncate(ext2_inode_t* inode, uint32_t inode_num, uint32_t new_size); // ── high-level (operate from a path string) ─────────────────────────────────── bool ext2_read_file_from_root(const char* name, uint8_t* buf, uint32_t* size); bool ext2_write_file_from_root(const char* name, const uint8_t* data, uint32_t size, ext2_write_mode_t mode); // ── create / delete ─────────────────────────────────────────────────────────── bool ext2_create_file(ext2_inode_t* dir, uint32_t dir_inum, const char* name, uint16_t mode, uint32_t* out_inum); bool ext2_mkdir(ext2_inode_t* parent, uint32_t parent_inum, const char* name, uint32_t* out_inum); bool ext2_unlink(ext2_inode_t* dir, uint32_t dir_inum, const char* name); bool ext2_rmdir(ext2_inode_t* parent, uint32_t parent_inum, const char* name); bool ext2_rename(ext2_inode_t* src_dir, uint32_t src_inum, ext2_inode_t* dst_dir, uint32_t dst_inum, const char* old_name, const char* new_name); // ── symlinks ────────────────────────────────────────────────────────────────── bool ext2_symlink(ext2_inode_t* dir, uint32_t dir_inum, const char* name, const char* target); bool ext2_readlink(uint32_t inode_num, char* buf, uint32_t buf_size); // ── metadata ───────────────────────────────────────────────────────────────── bool ext2_stat(uint32_t inode_num, ext2_stat_t* st); bool ext2_chmod(uint32_t inode_num, uint16_t mode); bool ext2_chown(uint32_t inode_num, uint16_t uid, uint16_t gid); const char* ext2_file_type_string(uint8_t type);