Writing basic functions using libdevmapper.h

[Taavi Ilves <ilvez@ut.ee>]

Hi!

I'm a quite C newbie, but for my school-project I need something to be 
done with device-mapper.

Problem is quite simple: I have a device-mapper device ( in /dev/mapper 
) and I must find out which loop ( or actually whatever ) device is 
behind that mapper-device device.

Example: status output with cryptsetup

# cryptsetup status /dev/mapper/secret10
/dev/mapper//dev/mapper/secret10 is active:
   cipher:  aes-cbc-plain
   keysize: 256 bits
   device:  /dev/loop/1
   offset:  0 sectors
   size:    917 sectors
   mode:    read/write

This device field is what I'm looking for. I have looked into dm-setup 
and cryptsetup too, where libdevmapper.h is being used to get such 
information, but those applications were quite advance for me to study.

So I seek documentation and maybe some simple examples to learn how to 
use libdevmapper.h . I don't need full source-code solution for my 
problem, but still I welcome anything that leads to the solution. Thanks 
ahead!

Best wishes,
Taavi Ilves