Quick HOWTO for UserModeLinux on Sourcemage
-------------------------------------------

Any comments direct towards me at tusker@tusker.org

Important websites:

http://www.stearns.org/mkrootfs/rootfs.html
http://user-mode-linux.sourceforge.net/UserModeLinux-HOWTO.html

NOTES:
	* Make sure your host kernel has TUN/TAP and/or ethertap support built in or module
	* modprobe iptable_nat
    * iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
	* echo 1 > /proc/sys/net/ipv4/ip_forward

1) Get the following files:
 cd /usr/src/uml
 wget http://unc.dl.sourceforge.net/sourceforge/user-mode-linux/uml-patch-2.4.20-4.bz2
 wget ftp://ftp.sg.kernel.org/pub/linux/kernel/v2.4/linux-2.4.20.tar.bz2
 wget http://unc.dl.sourceforge.net/sourceforge/user-mode-linux/uml_utilities_20030312.tar.bz2

2) Uncompress them into a directory, and apply the patch
 cd /usr/src/uml
 
 bzip2 -dc uml_utilities_20030312.tar.bz2 | tar -xvf -
 cd tools
 make; make install (will dump them into /usr/bin)
 # now make the kernel with the UM patches
 bzip2 -dc linux-2.4.20.tar.bz2 | tar -xvf -
 cd linux
 cat uml-patch-2.4.20-4.bz2 | bunzip2 - | patch -p1
 # you will need to edit ./fs/reiserfs/super.c and add a \ at the end of line 944 [or wherever the line is when the compile fails]
 
3) Build the "linux" binary:  Make sure you add network device support! :)
 make menuconfig ARCH=um
 make dep ARCH=um
 make linux ARCH=um
 

4) Grab the empty filesystem and mount it
 wget http://www.stearns.org/mkrootfs/emptyfs.ext3.1536.bz2
 cp -p --sparse=always <( cat emptyfs.ext3.1536.bz2 | bunzip2 -c - ) emptyfs.ext3.1536
 mv emptyfs.ext3.1536 root_fs
 mkdir /mnt/sm-root
 mount -o loop root_fs /mnt/sm-root

5) Mount the current ISO and extract image.tar.bz2
 mkdir /mnt/sm-iso
 mount -o loop ~/sm-latest.iso /mnt/sm-iso
 cd /mnt/sm-root
 bzip2 -dc /mnt/sm-iso/image.tar.bz2 | tar -xvf -

6) Install the Kernel modules that you created in step 3
 make modules ARCH=um
 make modules_install INSTALL_MOD_PATH=/mnt/sm-root ARCH=um

7) Make some changes to set the rootfs
 Add 
 /dev/ubd/0      /         ext3    defaults 0 0
 to
 /mnt/sm-root/etc/fstab
 
 Also remove the tmpfs stuff for now

8) unmount your loop devices, and boot the image :)
 umount /mnt/sm-root
 umount /mnt/sm-iso
 ./uml/linux-2.4.20/linux ubd0=uml/root_fs con0=fd:0,fd:1 con1=port:9000 con=pts eth0=tuntap,,,192.168.0.1