int fat_exists(const char *filename);
int fat_size(const char *filename, loff_t *size);
int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread);
int file_fat_read(const char *filename, void *buffer, int maxsize);
int fat_exists(const char *filename);
int fat_size(const char *filename, loff_t *size);
int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread);
int file_fat_read(const char *filename, void *buffer, int maxsize);