dm driver ioctl call
 

I'm writing a user space program which should figure out if a device is active or not and secondly should classify the type of device it is..

the three types I have are --- /dev/sg*, /dev/sd* and /dev/md*
I'm using the default md driver for raid.
Now I wanted to make some ioctl calls to find out if a certain device exists or not, but was facing a lot of problems doing this..

can someone please help!! or suggest an easier way of doing it (other than string manipulation methods)...

Thanks