RFC: ntdll: Implement CDROM_GetInterfaceInfo() on Mac OS (try 2)

[Charles Davis]

Charles Davis wrote:
> Alexandre Julliard wrote:
>> Charles Davis <cdavis at mymail.mines.edu> writes:
>>
>>> Oh, I see. You mean I should open a handle to mountmgr with
>>> NtOpenFile(). That's what I thought. Now I just need to figure out the
>>> right IOCTL. Maybe I need to make one up. And I still don't know how to
>>> specify the correct device to mountmgr. (The answer is "depends on the
>>> IOCTL," so I need to answer the first question before I can answer this
>>> one.)
>> There's no new ioctl here, just an open. That is essentially supported
>> already.
>>
>>> Another thing I don't quite understand: what good would an FD from the
>>> mountmgr device do? I looked at mountmgr, and I don't see any code for
>>> handing out FDs. No open()s, no sendmsg()s, no nothing. The only
>>> function I see in ntdll for this is server_get_unix_fd(), which is what
>>> we use to get the device FD from the NT CD-ROM device handle, and again
>>> I don't see how that will help. I mean, it's probably something like a
>>> socket or a pipe so all we can do is read and write it. (With sockets,
>>> we have some system IOCTLs, but they're all for controlling the socket
>>> itself.) And that's if there even is one. I looked at wineserver, and it
>>> looks like some file objects don't have to have real FDs behind them. Or
>>> did you have a different FD in mind, one I haven't thought of?
>> There's no mechanism for this at the moment, that's why I said some
>> infrastructure is needed. mountmgr should be asked to open the unix
>> device corresponding to the NT device, and that fd should get back to
>> the app somehow.
>>
> Oh, OK, I see what you're getting at. (Can't believe I didn't see it
> sooner...) I open mountmgr, then I ask it for the unix FD for the parent
> of the partition, corresponding to the NT device. You want me to move
> the process of getting the parent FD to mountmgr.
Or, maybe not. I could be totally wrong about that. Maybe what you
really want is for me to get an FD from mountmgr so I can talk to it at
will. I don't know.

We can even add the FD to mountmgr's run loop (via a CFFileDescriptor
object), or if you prefer, we can do the traditional select() or poll()
loop. (But why spawn another thread just for that?)