e8cf30c805
read-mode access to CD-ROM media in the worm(4) driver. No whistles and bells yet, like all the CDIO* commands, but at least a start. In order to do this, i had to slightly rearrange the semantics of an open(2) on the worm driver: now, opening it with O_NONBLOCK set means no actual IO operations will be intended but only ioctls are to be processed. This mode is used by wormcontrol(8) to prepare a track and/or session. I have only been able to test this on a 2.2-GAMMA system by now, and only the !DEVFS part is tested yet. Also, i have only done a dummy burn so far, but wouldn't expect many surprises else. Report bugs to me ASAP, if there's reasonable demand and i hear no objections, i might consider merging it into the 2.2 branch as well.