unionfs?

Alexander E. Patrakov patrakov at ums.usu.ru
Fri Apr 22 08:56:07 PDT 2005


On Thursday 21 April 2005 11:21, I wrote:

> use unionfs to pretend that the CD can be written to.

A magic binary blob (klibc-based) that does this trick is available at:

http://ums.usu.ru/~patrakov/uniontest/initramfs_data.cpio.gz

It may or may not work with the current SVN livecd because I omitted reiser4 
kernel patches and the unionfs kernel module may or may not fit.

Arbitrary file can be overwritten and even "deleted" from the livecd until the 
reboot. This initramfs expects the following layout of the CD:

./boot/isolinux
./boot/isolinux/boot.msg
./boot/isolinux/isolinux.bin
./boot/isolinux/isolinux.cfg
./boot/isolinux/linux
./boot/isolinux/options.msg
./boot/isolinux/splash.lss
./root.sqfs
./sources/binutils-2.15.94.0.2.2.tar.bz2
<other sources>
./sources/zlib-1.2.2.tar.bz2

root.sqfs is produced by running the following commands:

umount -a # so that /proc and /sys are empty
          # and /dev contains only the minimal set of nodes
mksquashfs / /iso/root.sqfs -e /boot /lfs-livecd /iso /sources

As for bootscripts, the "mountkernfs" and "udev" scripts are needed in 
addition to the standard livecd set. No need to mount squashed /usr or unpack 
root.tar.gz and etc.tar.gz tarballs.

Sorry for not providing sources and makefiles. I have not yet scripted the 
build procedure of this initramfs. Will do so in a day or two.

-- 
Alexander E. Patrakov



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