function::user_string_n_quoted — Retrieves and quotes string from user space
the user space address to retrieve the string from
the maximum length of the string (if not null terminated)
Returns up to n characters of a C string from the given user space memory address where any ASCII characters that are not printable are replaced by the corresponding escape sequence in the returned string. Reports “NULL” for address zero. Returns “<unknown>” on the rare cases when userspace data is not accessible at the given address.