Detect already installed partitions.

[Rabbul Nawaz <rabbul.nawaz@deeproot.co.in>]

Hello, 

I am working on deepOfix, one of the distribution of GNU/Linux which follows 
debian based packaging [ http://code.deeproot.in/deepofix/ ]. I would like to 
know, the procedure how the debian-installer detects the existing partition 
labels and displays them. I mean when we select "manual partition", during 
the installation, the installer shows the existing partitions. I am able to 
get the partition table information from the /proc/partitions in the 
installer environment of deepOfix, but would  like to display the 
partition-labels information also, as debian does.

I could not find much information by google. 
The installer environment of deepOfix has just busybox commands available. I 
guess if I could find the partition-label information through /proc. I also 
checked the /dev/disk/by-id & /dev/disk/by-path , but could not get the 
required information. Can some one help me out in this. I tried my best to 
explain, if it is not clear, please let me know, so that I can try to explain 
in a more lucid way.

Regards,
Rabbul Nawaz.