OS X fixes:
* Applied Eugenio's fix to the DVDioctl driver. I didn't test it, but
it should not hang the kernel anymore.
* Ported most dvd_ioctl.c functions to the DVDioctl driver: ReportAgid,
ReportChallenge, ReportKey1, ReportASF, InvalidateAgid, SendChallenge,
SendKey2. They should comply with the "Mt. Fuji Commands for Multimedia
Last remaining problem: ReadCopyright and ReadKey. The version of
Darwin I have here only has reportKey() and sendKey() functions in
the IODVDBlockStorageDevice class (pages 413 and 449 of the Mt. Fuji
paper), but we also need the READ_STRUCTURE (page 357) which I couldn't
find anywhere in the kernel headers. Either I missed it, or we'll have
to wait for Apple to implement it (or maybe we can emulate this command
with some other IOKit commands).