Clarification regarding design of a device.

[mindentropy]

On Monday 02 May 2011 10:58:45 PM Mulyadi Santosa wrote:
> 
> I am not keen regarding char/block device management, but I think you
> should separate those streams.
> 
> How? Well, same thing like you open a same file twice, right? You're
> given two different file descriptor. After all, the "open", "read" and
> "write" handler of device IMHO always assume that we wanna achieve
> such different stream, right?

Sounds silly but how do I get access to the file descriptor?

Also If I make the user create a session for an operation similar to this 
paper 
http://www.usenix.org/event/usenix03/tech/full_papers/keromytis/keromytis_html/node8.html#SECTION00042000000000000000, 
should I remove the read, write operations and do all operations using ioctl 
commands i.e. reading the user buffer etc?