# Building a RedHat root image

The image required to use User-Mode-Linux is just a normal set of executables. These can be extracted from a RedHat distribution using the following proceedure.

There is a script in testing/utils called `uml-rhroot.sh`. It takes two arguments:

- a directory in which to put resulting directory tree.
- a directory tree containing the RedHat distribution RPMs. This may be in one of three forms:
  - a directory containing the directories "disc1" and "disc2". These could be ISO images that are mounted loopback via, for instance:

        mkdir -p /distros/redhat/7.2/disc1 /distros/redhat/7.2/disc1
        mount -t iso9660 -o loop,ro /distros/redhat/7.2/enigma-i386-disc1.iso /distros/redhat/7.2/disc1
        mount -t iso9660 -o loop,ro /distros/redhat/7.2/enigma-i386-disc2.iso /distros/redhat/7.2/disc2

    or even two real CDroms mounted somewhere. In the example above, use "/distros/redhat/7.2" as the distribution directory.
  - a directory containing a "merged" disc1 and disc2 as suggested by RedHat in http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/install-guide/s1-install-network.html under "Setting up the Server".
  - a directory containing all the required RPMs. (See list of RPMs)

The unpacked distribution will take approximately 133Mb. You will want to locate this on the same partition as your intended root trees for your User-Mode-Linux's as this will permit hard links to be used, saving disk space.

Because the RPM command used uses the chroot(2) system call and needs to change ownership of the files that it creates, it must be run as root. Afterward, you should chown the entire directory to the userid that you will be using for testing (i.e. probably yours). It should eventually suffices to make sure that you can read every file.

You should be able to chroot to this directory and run programs. If you can not at least run ls, then there is a problem.

Expect a couple of errors about install-info.

An example:

    Script started on Thu Nov 22 15:51:15 2001
    cassidy:/c2/user-mode-linux# df
    Filesystem           1k-blocks      Used Available Use% Mounted on
    /dev/hda1              3844408   1673528   1975584  46% /
    /dev/hda3             12495048   1823404  10036884  16% /home
    /dev/hdc1             10325748    805056   8996172   9% /c1
    /dev/hdc2             10325780   4815160   4986100  50% /c2
    /dev/hdc3             10325780   2972480   6828780  31% /c3
    /dev/hdc4              7495084   3059640   4054704  44% /c4
    /distros/redhat/7.2/enigma-i386-disc1.iso
                            662072    662072         0 100% /distros/redhat/7.2/disc1
    /distros/redhat/7.2/enigma-i386-disc2.iso
                            653740    653740         0 100% /distros/redhat/7.2/disc2
    cassidy:/c2/user-mode-linux# /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh
    Usage: /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh rootdir cdimagedir
    cassidy:/c2/user-mode-linux# /c2/freeswan/sandbox-main/testing/utils/uml-rhroot.sh /c2/user-mode-linux/rpm-root/root /distros/redhat/7.2
    Assuming RH disc1 at /distros/redhat/7.2/disc1/RedHat/RPMS
            and disc2 at /distros/redhat/7.2/disc2/RedHat/RPMS
    /var/tmp/rpm-tmp.99149: /sbin/install-info: No such file or directory
    error: execution of %post scriptlet from textutils-2.0.14-2 failed, exit status 127
    cat: /proc/mounts: No such file or directory
    warning: /var/lib/rpm/Basenames created as /var/lib/rpm/Basenames.rpmnew
    warning: /var/lib/rpm/Conflictname created as /var/lib/rpm/Conflictname.rpmnew
    warning: /var/lib/rpm/Group created as /var/lib/rpm/Group.rpmnew
    warning: /var/lib/rpm/Name created as /var/lib/rpm/Name.rpmnew
    warning: /var/lib/rpm/Packages created as /var/lib/rpm/Packages.rpmnew
    warning: /var/lib/rpm/Providename created as /var/lib/rpm/Providename.rpmnew
    warning: /var/lib/rpm/Requirename created as /var/lib/rpm/Requirename.rpmnew
    warning: /var/lib/rpm/Triggername created as /var/lib/rpm/Triggername.rpmnew
    You should now chown it to yourself.
    cassidy:/c2/user-mode-linux# chown -R mcr rpm-root/root
    cassidy:/c2/user-mode-linux# ls rpm-root/root
    bin   dev  home    lib	opt   root  tmp  var
    boot  etc  initrd  mnt	proc  sbin  usr
    cassidy:/c2/user-mode-linux# chroot rpm-root/root
    cassidy:/# ls
    bin   dev  home    lib  opt   root  tmp  var
    boot  etc  initrd  mnt  proc  sbin  usr
    cassidy:/# exit
    cassidy:/c2/user-mode-linux# exit
    Script done on Thu Nov 22 15:54:33 2001