#!/bin/bash

#
# Create an LXC RHEL-based container
# Inspired by: http://wiki.1tux.org/wiki/Centos6/Installation/Minimal_installation_using_yum
#              http://wiki.1tux.org/wiki/Lxc/Installation/Guest/Centos/6
#              https://github.com/docker/docker/blob/master/contrib/mkimage-yum.sh
#

get_release_package () {
    local url=$1
    local relase_package=$2
    curl $url | grep $relase_package | sed -n 1p | sed 's/.*\( \|>\)\([^ <>]\+\.rpm\).*/\2/'
}

create_repofiles () {
    local os_type=$1
    local os_version=$2
    local os_arch=$3

    case $os_type in
        centos)
            local os_url="ftp://ftp.tlk-l.net/pub/mirrors/centos.org/$os_version/os/$os_arch/Packages/"
            local release_package="release"
        ;;
        scientific)
            local os_url="http://mirror.imbg.org.ua/pub/linux/scientific/$os_version/$os_arch/os/Packages/"
            local release_package="sl-release"
        ;;
        *)
            echo "$os_type type is not supported."
            exit 1
        ;;
    esac

    local release_rpm=$( get_release_package $os_url $release_package )
    cd $ROOTFSDIR
    curl $os_url/$release_rpm > $release_rpm
    rpm2cpio $release_rpm | cpio -idm
    sed -i "s/\$releasever/$os_version/g" ./etc/yum.repos.d/*
    rm -f $release_rpm

    [ "$os_arch" != "$( uname -i)" ] && setarch $os_arch
}

yum_install_footfs () {
    yum --nogpgcheck --assumeyes --installroot=$ROOTFSDIR --setopt=tsflags=nodocs \
        --setopt=group_package_types=mandatory groupinstall Core
    yum --nogpgcheck --assumeyes --installroot=$ROOTFSDIR install \
        openssh-server vim-enhanced wget man mc
    yum --nogpgcheck --assumeyes --installroot=$ROOTFSDIR clean all
}

make_device_nodes () {
    local target=$ROOTFSDIR
    rm -rf "$target"/dev
    mkdir -m 755  "$target"/dev
    mkdir -m 1777 "$target"/dev/shm
    mkdir -m 755  "$target"/dev/pts
    mknod -m 600  "$target"/dev/console c 5 1
    mknod -m 600  "$target"/dev/initctl p
    mknod -m 666  "$target"/dev/full c 1 7
    mknod -m 666  "$target"/dev/null c 1 3
    mknod -m 666  "$target"/dev/ptmx c 5 2
    mknod -m 666  "$target"/dev/random c 1 8
    mknod -m 666  "$target"/dev/tty c 5 0
    mknod -m 666  "$target"/dev/tty0 c 4 0
    mknod -m 666  "$target"/dev/tty1 c 4 1
    mknod -m 666  "$target"/dev/urandom c 1 9
    mknod -m 666  "$target"/dev/zero c 1 5
}

make_files () {
    local target=$ROOTFSDIR
    cp -a "$target"/etc/skel/. "$target"/root/.
    cat > /etc/hosts << END
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
END
    cat > "$target"/etc/sysconfig/network << END
NETWORKING=yes
END
    cat > "$target"/etc/fstab << END 
/dev/root               /                       rootfs   defaults        0 0
none                    /dev/shm                tmpfs    nosuid,nodev    0 0
END
}

create_upstart_script () {
    local target=$ROOTFSDIR
    cat > "$target"/etc/init/lxc-sysinit.conf << END
start on startup
env container

pre-start script
        if [ "x$container" != "xlxc" -a "x$container" != "xlibvirt" ]; then
                stop;
        fi
        initctl start tty TTY=console
        rm -f /var/lock/subsys/*
        rm -f /var/run/*.pid
        telinit 3
        exit 0;
end script
END
}

visual_tuning () {
    local target=$ROOTFSDIR
    local host_name=$( hostname -s | tr '[a-z]' '[A-Z]' )
    cat >> "$target"/root/.bashrc << END

# Colorize BASH prompt for root
PS1="\[\033[1;31m\]${host_name}\[\033[0;31m\]:\[\033[0;36m\]LXC\[\033[0;31m\]:\[\033[0;33m\]\h \[\033[1;31m\][\u \W]#\[\033[0;39m\] "
END
}

# parse command line options
while getopts "d:t:v:a:" opt; do
  case $opt in
    d)
      export ROOTFSDIR="$OPTARG"
      ;;
    t)
      os_type="$OPTARG"
      ;;
    v)
      os_version="$OPTARG"
      ;;
    a)
      os_arch="$OPTARG"
      ;;
  esac
done

# defaults
[ -z "$ROOTFSDIR" ] && exit 1
[ -z "$os_arch" ] && os_arch="x86_64"
[ -z "$os_type" ] && os_type="centos"
[ -z "$os_version" ] && os_version="6.6" #TODO: function to get latest version

mkdir -p $ROOTFSDIR

create_repofiles "$os_type" "$os_version" "$os_arch"
yum_install_footfs
make_device_nodes
make_files
visual_tuning

if [ "$os_type" = "centos" -o "$os_type" = "scientific" ]; then
    [ "${os_version:0:1}" = "6" ] && create_upstart_script
fi