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