#!/bin/bash
#
# proof of concept script to create a bootable 'deployment' floppy
#
# This one can run on a centos7, to generate a boot floppy for a centos7.
# 

Self=$(basename $0)

function print_usage {
  echo "usage: $Self <options>"
}

function print_help {
cat <<EOF
$Self <options>

Script to create a bootable 'install' floppy image.

The image uses ipxe to retrieve a kernel to boot, and sets URLs for the
'install' initrd and kickstart config the kernel should use.

The whole thing is pretty CentOS 7 -centric at this point.

Options given to this script will set values for the bootstrapping of the 
*install* stage only. All values may subsequently be overridden from the 
kickstart stage, once that is retrieved and control is handed over to it.

Options:
  -D, --domain		domain, to complete FQDN
  -G, --gateway 	Gateway of target system
  -H, --host		hostname of the target system
  -I, --ip		IP address of target system
  -K, --kserver		Kickstart server
  -M, --netmask		Netmask of target system
  -N, --nameserver	Nameserver of target system
  -S, --cosmos-hash	Hash used by cosmos to verify stuff
  -h, --help		this
  --inst-cmdline        add stuff to the install system kernel command line

If --cosmos-hash is set to 'disabled', the kickstart stage should skip cosmos
bootstrapping, and leave the system unmanaged.

If -N, -K, -S options are not given, default values are provided.

To avoid shell interpretation of whitespace in --inst-cmdline use escaped 
semicolon:
  To achieve this:
    console=tty1 console=ttyS0,115200n8
  write this:
    console=tty1\;console=ttyS0,115200n8

The script needs ipxe and syslinux to run, and 'sudo' to copy things onto the
floppy image

EOF
}

function parse_commadline {
  while [ "$#" -gt 0 ] ; do
    case "$1" in
    -h|--help)
      print_help
      exit 0
      ;;
    -H|--host)
      Host="$2"
      shift
      ;;
    -D|--domain)
      Domain="$2"
      shift
      ;;
    -I|--ip)
      IP="$2"
      shift
      ;;
    -M|--netmask)
      NM="$2"
      shift
      ;;
    -G|--gateway)
      GW="$2"
      shift
      ;;
    -N|--nameserver)
      NS="$2"
      shift
      ;;
    -K|--kserver)
      Kserver="$2"
      shift
      ;;
    -P|--publish-path)
      PublishPath="$2"
      shift
      ;;
    -S|--cosmos-hash)
      CosmosHash="$2"
      shift
      ;;
    -T|--tmp-dir)
      TmpDir="${2}"
      shift
      ;;
    --inst-cmdline)
      InstCmdLineOpt="$(echo ${2} | sed -e 's/;/ /g')"
      shift
      ;;
    --gen-cmd)
      GeneratorCommand="$(echo ${2} | sed -e 's/;:;/ /g')"
      shift
      ;;
    *)
      echo "what do you mean \"$1\"?"
      exit 1
      ;;
    esac
    shift
  done
}

function check_options {
  if [ "x${Host}" = "x" ]
  then
    echo "${Self}: --host is mandatory"
    print_usage
    exit 1
  fi
  if [ "x${Domain}" = "x" ]
  then
    echo "${Self}: --domain is mandatory"
    print_usage
    exit 1
  fi
  if [ "x${IP}" = "x" ]
  then
    echo "${Self}: --ip is mandatory"
    print_usage
    exit 1
  fi
  if [ "x${NM}" = "x" ]
  then
    echo "${Self}: --netmask is mandatory"
    print_usage
    exit 1
  fi
  if [ "x${GW}" = "x" ]
  then
    echo "${Self}: --gateway is mandatory"
    print_usage
    exit 1
  fi
  if [ "x${NS}" = "x" ]
  then
    NS="109.105.96.141"
  fi
  if [ "x${Kserver}" = "x" ]
  then
    Kserver="109.105.122.84"
  fi
  if [ "x${CosmosHash}" = "x" ]
  then
    CosmosHash="2ea14b0b958fdc70ad37e3cb9b4185b3648137b8"
  fi
  if [ "x${TmpDir}" = "x" ]
    then
    TmpDir=$(mktemp -d)
  else
    mkdir -p "${TmpDir}"
  fi
}

# Host="kas-fiona-10-02"
# Domain="nordu.net"
# IP="109.105.122.135"
# NM="255.255.255.192"
# GW="109.105.122.129"
# NS="109.105.96.141"
# Kserver="109.105.122.84"
# CosmosHash="2f15e1edb02f14607084f167929bc145ed47954d"

parse_commadline $@
check_options

####
# In a bid to be clever, we're adding the 'cosmos hash' to the install
# kernel cmdline. This is the one place that cannot be forged, changed, get
# lost or 'go missing' from the initial invocation here, until the
# anaconda/kickstart process takes over...

WorkDir="${TmpDir}/${Host}.d"
mkdir -p ${WorkDir}/mnt

dd if=/dev/zero of=${WorkDir}/${Host}.img bs=2x80x18b count=1
mkfs.ext2 -F "${WorkDir}/${Host}.img"
sudo mount -o loop ${WorkDir}/${Host}.img ${WorkDir}/mnt

sudo sh -c "cat >${WorkDir}/mnt/extlinux.conf <<EOF
default ipxelabel
label ipxelabel
kernel /ipxe.lkrn
append initrd=/${Host}.ipxe
EOF"

# We want to use variables in the rendered *.ipxe
# We want to populate the variables in the *.ipxe with variables from this
# script.
# Redirection of output from the here-doc into a file needs root privs, because
# there's no real directory structure in the floppy filesystem, and mounting
# as a user is... also complicated.
# This all leads to the 'sudo sh -c "cat ..."' construct, which works well
# ...except:
# Quoting and escapes get complicated as a consequence. The upshot is that
# you *can* use your variables, and keep them too, but it has a price.

sudo sh -c "cat >${WorkDir}/mnt/${Host}.ipxe <<EOF
#!ipxe
#
# This file generated with this command:
# ${GeneratorCommand}
#
echo ${Host}
ifopen net0
###
# Set some variables:
set ip ${IP}
set nm ${NM}
set gw ${GW}
set ns ${NS}
set hn ${Host}
set dn ${Domain}
set ks ${Kserver}

###
# Set up network:
set net0/ip \\$"{"ip"}"
set net0/netmask \\$"{"nm"}"
set net0/gateway \\$"{"gw"}"
set dns \\$"{"ns"}"
set hostname \\$"{"hn"}"
set domain \\$"{"dn"}"
###
# Print some things on screen
echo \"Configured IP Details:\"
show net0/ip
show net0/netmask
show net0/gateway
show dns
show hostname
show domain
route
###
# Set install parameters:
set base http://\\$"{"ks"}"/install/centos/7/os/x86_64
kernel \\$"{"base"}"/images/pxeboot/vmlinuz text ${InstCmdLineOpt} ip=\\$"{"ip"}" netmask=\\$"{"nm"}" gateway=\\$"{"gw"}" repo=\\$"{"base"}" ks=http://\\$"{"ks"}"/install/ks/\\$"{"hn"}".ks cosmoshash=${CosmosHash}
initrd \\$"{"base"}"/images/pxeboot/initrd.img
###
# Boot into install
boot
####
# We really never should be here, but if we are, start a shell
echo \"why are we here?\"
shell
EOF
"

#read

if [ -r /etc/redhat-release ]
then
  sudo cp -a /usr/share/ipxe/ipxe.lkrn ${WorkDir}/mnt/
elif [ -r /etc/debian_version ]
then
  sudo cp -a /boot/ipxe.lkrn ${WorkDir}/mnt/
else
  echo "neither redhat nor debian, I'm outta here..."
  exit 1
fi
sudo extlinux --install ${WorkDir}/mnt/
sudo umount ${WorkDir}/mnt/

if [ ! "x${PublishPath}" = "x" ]
then
  mkdir -p "${PublishPath}/${Host}.d/"
  mv "${WorkDir}/${Host}.img" "${PublishPath}/${Host}.d/"
  rm -rf ${WorkDir}
else
  echo "no PublishPath set, leaving everything in ${WorkDir}"
fi