// Copyright (c) 2023-2026 Chris (boreddevnl) // This software is released under the GNU General Public License v3.0. See LICENSE file for details. // This header needs to maintain in any file it is present in, as per the GPL license terms. #ifndef FAT32_H #define FAT32_H #include #include // === FAT32 Structures === // Boot Sector (512 bytes) typedef struct { uint8_t jmp[3]; // Jump instruction uint8_t oem[8]; // OEM identifier uint16_t bytes_per_sector; // Bytes per sector (usually 512) uint8_t sectors_per_cluster; // Sectors per cluster uint16_t reserved_sectors; // Reserved sectors (usually 1) uint8_t num_fats; // Number of FATs (usually 2) uint16_t root_entries; // Root directory entries (0 for FAT32) uint16_t total_sectors_16; // Total sectors 16-bit (0 for FAT32) uint8_t media_descriptor; // Media descriptor uint16_t sectors_per_fat_16; // Sectors per FAT 16-bit (0 for FAT32) uint16_t sectors_per_track; // Sectors per track uint16_t num_heads; // Number of heads uint32_t hidden_sectors; // Hidden sectors uint32_t total_sectors_32; // Total sectors 32-bit // FAT32 Specific uint32_t sectors_per_fat_32; // Sectors per FAT 32-bit uint16_t flags; // Flags uint16_t version; // Version uint32_t root_cluster; // Root directory cluster uint16_t fsinfo_sector; // FSInfo sector number uint16_t backup_boot_sector; // Backup boot sector number uint8_t reserved[12]; // Reserved uint8_t drive_number; // Drive number uint8_t reserved2; // Reserved uint8_t boot_signature; // Boot signature uint32_t serial_number; // Volume serial number uint8_t volume_label[11]; // Volume label uint8_t fs_type[8]; // Filesystem type ("FAT32 ") uint8_t boot_code[420]; // Boot code uint16_t boot_signature_value; // Boot signature value (0xAA55) } __attribute__((packed)) FAT32_BootSector; // Directory Entry (32 bytes) typedef struct { uint8_t filename[8]; // Filename (8 bytes) uint8_t extension[3]; // Extension (3 bytes) uint8_t attributes; // File attributes uint8_t reserved; // Reserved uint8_t creation_time_tenths; // Creation time (tenths of second) uint16_t creation_time; // Creation time (HH:MM:SS) uint16_t creation_date; // Creation date (YYYY:MM:DD) uint16_t last_access_date; // Last access date uint16_t start_cluster_high; // Start cluster (high word) uint16_t write_time; // Write time uint16_t write_date; // Write date uint16_t start_cluster_low; // Start cluster (low word) uint32_t file_size; // File size } __attribute__((packed)) FAT32_DirEntry; // Long File Name Directory Entry (32 bytes) typedef struct { uint8_t order; // Sequence number (0x40 = last, | index) uint16_t name1[5]; // Characters 1-5 (UCS-2) uint8_t attr; // Always 0x0F uint8_t type; // Always 0x00 uint8_t checksum; // Checksum of short name uint16_t name2[6]; // Characters 6-11 (UCS-2) uint16_t first_cluster; // Always 0x0000 uint16_t name3[2]; // Characters 12-13 (UCS-2) } __attribute__((packed)) FAT32_LFNEntry; // File Attributes #define ATTR_READ_ONLY 0x01 #define ATTR_HIDDEN 0x02 #define ATTR_SYSTEM 0x04 #define ATTR_VOLUME_ID 0x08 #define ATTR_DIRECTORY 0x10 #define ATTR_ARCHIVE 0x20 #define ATTR_DEVICE 0x40 #define ATTR_RESERVED 0x80 #define ATTR_LFN 0x0F // LFN marker (all of the above ORed) // FAT32 Constants #define FAT32_SECTOR_SIZE 512 #define FAT32_CLUSTER_SIZE 4096 // 8 sectors per cluster #define FAT32_MAX_FILENAME 256 #define FAT32_MAX_PATH 1024 #define FAT32_ROOT_CLUSTER 2 // File Handle typedef struct { uint32_t cluster; // Current cluster uint32_t start_cluster; // Start cluster (for file entry lookup) uint32_t position; // Current position in file uint32_t size; // File size uint32_t mode; // 0=read, 1=write, 2=append bool valid; // Is this handle valid? uint32_t dir_sector; // Sector containing the directory entry uint32_t dir_offset; // Offset within that sector bool is_directory; // Is this a directory? uint8_t attributes; // File attributes void *volume; // Pointer to owning FAT32_Volume (or NULL for ramfs) } FAT32_FileHandle; // Directory Entry Info (for listing) typedef struct { char name[FAT32_MAX_FILENAME]; uint32_t size; bool is_directory; uint32_t start_cluster; uint16_t write_date; uint16_t write_time; } FAT32_FileInfo; // === VFS Integration === // Forward-declared VFS ops type (defined in vfs.h) struct vfs_fs_ops; // Get VFS ops structs for registration struct vfs_fs_ops* fat32_get_ramfs_ops(void); struct vfs_fs_ops* fat32_get_realfs_ops(void); // Mount a real FAT32 volume from a block device — returns fs_private for VFS void* fat32_mount_volume(void *disk_ptr); // === Function Declarations === // Initialization void fat32_init(void); // File Operations (backward-compat wrappers — dispatch through VFS) FAT32_FileHandle* fat32_open(const char *path, const char *mode); void fat32_close(FAT32_FileHandle *handle); int fat32_read(FAT32_FileHandle *handle, void *buffer, int size); int fat32_write(FAT32_FileHandle *handle, const void *buffer, int size); int fat32_seek(FAT32_FileHandle *handle, int offset, int whence); // Directory Operations bool fat32_mkdir(const char *path); bool fat32_rmdir(const char *path); bool fat32_delete(const char *path); bool fat32_exists(const char *path); bool fat32_rename(const char *old_path, const char *new_path); bool fat32_is_directory(const char *path); // Listing int fat32_list_directory(const char *path, FAT32_FileInfo *entries, int max_entries); // Info int fat32_get_info(const char *path, FAT32_FileInfo *info); // Working Directory (backward compat — wraps VFS path tracking) bool fat32_chdir(const char *path); void fat32_get_current_dir(char *buffer, int size); bool fat32_change_drive(char drive); char fat32_get_current_drive(void); // Utilities void fat32_normalize_path(const char *path, char *normalized); bool fs_starts_with(const char *str, const char *prefix); // Root volume sync helpers void fat32_set_root_volume(void *fs_private); // Desktop Limit void fat32_set_desktop_limit(int limit); #endif