#!/bin/bash
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# to you under the Apache License, Version 2.0 (the
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# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
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# Copies keys that enable SSH communication with system vms
# $1 = new public key
# $2 = new private key

#set -x
set -e

TMP=/tmp
MOUNTPATH=${HOME}/systemvm_mnt
TMPDIR=${TMP}/cloud/systemvm
umask 022

clean_up() {
  $SUDO umount $MOUNTPATH
}

inject_into_iso() {
  local isofile=${systemvmpath}
  local newpubkey=$2
  local backup=${isofile}.bak
  local tmpiso=${TMP}/$1
  mkdir -p $MOUNTPATH
  [ ! -f $isofile ] && echo "$(basename $0): Could not find systemvm iso patch file $isofile" && return 1
  $SUDO mount -o loop $isofile $MOUNTPATH 
  [ $? -ne 0 ] && echo "$(basename $0): Failed to mount original iso $isofile" && clean_up && return 1
  diff -q $MOUNTPATH/authorized_keys $newpubkey &> /dev/null && echo "New public key is the same as the one in the systemvm.iso, not injecting it, not modifying systemvm.iso" && clean_up && return 0
  $SUDO cp -b $isofile $backup
  [ $? -ne 0 ] && echo "$(basename $0): Failed to backup original iso $isofile" && clean_up && return 1
  rm -rf $TMPDIR
  mkdir -p $TMPDIR
  [ ! -d $TMPDIR  ] && echo "$(basename $0): Could not find/create temporary dir $TMPDIR" && clean_up && return 1
  $SUDO cp -fr $MOUNTPATH/* $TMPDIR/
  [ $? -ne 0 ] && echo "$(basename $0): Failed to copy from original iso $isofile" && clean_up && return 1
  $SUDO cp $newpubkey $TMPDIR/authorized_keys
  [ $? -ne 0 ] && echo "$(basename $0): Failed to copy key $newpubkey from original iso to new iso " && clean_up && return 1
  mkisofs -quiet -r -o $tmpiso $TMPDIR
  [ $? -ne 0 ] && echo "$(basename $0): Failed to create new iso $tmpiso from $TMPDIR" && clean_up && return 1
  $SUDO umount $MOUNTPATH
  [ $? -ne 0 ] && echo "$(basename $0): Failed to unmount old iso from $MOUNTPATH" && return 1
  $SUDO cp -f $tmpiso $isofile
  [ $? -ne 0 ] && echo "$(basename $0): Failed to overwrite old iso $isofile with $tmpiso" && return 1
  rm -rf $TMPDIR
}

copy_priv_key() {
  local newprivkey=$1
  diff -q $newprivkey $(dirname $0)/id_rsa.cloud && return 0
  $SUDO cp -fb $newprivkey $(dirname $0)/id_rsa.cloud
  $SUDO chmod 644 $(dirname $0)/id_rsa.cloud
  return $?
}

if [[ "$EUID" -ne 0  ]]
then
   SUDO="sudo -n "
fi

$SUDO mkdir -p $MOUNTPATH

[ $# -ne 3 ] && echo "Usage: $(basename $0)  <new public key file> <new private key file> <systemvm iso path>" && exit 3
newpubkey=$1
newprivkey=$2
systemvmpath=$3
[ ! -f $newpubkey ] && echo "$(basename $0): Could not open $newpubkey" && exit 3
[ ! -f $newprivkey ] && echo "$(basename $0): Could not open $newprivkey" && exit 3

command -v mkisofs > /dev/null   || (echo "$(basename $0): mkisofs not found, please install or ensure PATH is accurate" ; exit 4)

# if running into Docker as unprivileges, skip ssh verification as iso cannot be mounted due to missing loop device.
if [ -f /.dockerenv ]; then
  if [ -e /dev/loop0 ]; then
    # it's a docker instance with privileges.
    inject_into_iso systemvm.iso $newpubkey
    [ $? -ne 0 ] && exit 5
    copy_priv_key $newprivkey
  else
    # this mean it's a docker instance, ssh key cannot be verify.
    echo "We run inside Docker, skipping ssh key insertion in systemvm.iso"
  fi
else
  inject_into_iso systemvm.iso $newpubkey
  [ $? -ne 0 ] && exit 5
  copy_priv_key $newprivkey
fi