void file_close (struct file *);
off_t file_read (struct file *, void *, off_t);
off_t file_read_at (struct file *, void *, off_t size, off_t start);
void file_close (struct file *);
off_t file_read (struct file *, void *, off_t);
off_t file_read_at (struct file *, void *, off_t size, off_t start);