- Allow device probing again (this should fix the problem Arnaldo de Melo

- Allow device probing again (this should fix the problem Arnaldo de Melo
reported)

- Various cleanups and bug fixes.

- Better error message for ENODEV.

- Proper exit codes for interface printing

- Add safe_strncpy and use it everywhere: this fixes quite a lot of
strncpy bugs (strncpy doesn't add a '\0' when the source string is too
long!)