opening files

[luc deschenaux <luc.deschenaux@freesurf.ch>]

maybe somebody did it already, knows where i need to do it, or has 
something to say about it; so while i start looking how to implement the 
functionality described below, i post a message here

When booting from a livecd, the empty directory tree is duplicated in a 
tmpfs partition and all the cdrom files are linked in it

If a process need to open a file with write permission you have to 
remove the link in ramdisk and replace it with the real file from the cd 
at user level

I'm looking to patch the kernel or libraries so that when a process try 
to open such linked file with write permission, the kernel or library 
replace the link in ramdisk with the real file from cd before opening it 
and returning the file descriptor instead of a "permission denied" error.

infos and suggestions welcome

regards,

Luc