build_freebsd_iso

#!/usr/bin/env zsh

if [[ -n "$TRACE" ]]; then
  export PS4='[\D{%FT%TZ}] ${BASH_SOURCE}:${LINENO}: ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
  set -o xtrace
fi

set -euo pipefail
IFS=$'\n\t'

RELEASE=${RELEASE:-12.2}
MIRROR="ftp.uk.freebsd.org"
MIRROR_PATH="pub/FreeBSD/releases/ISO-IMAGES"
# ISO="FreeBSD-${RELEASE}-RELEASE-amd64-bootonly.iso"
ISO="FreeBSD-${RELEASE}-RELEASE-amd64-disc1.iso"
ISO_DIR="data/freebsd-iso"
ISO_MOUNT="/mnt/freebsd-iso"
CUSTOM_ISO_LAYOUT="data/custom-freebsd-iso"
SHA256SUM="CHECKSUM.SHA256-FreeBSD-${RELEASE}-RELEASE-amd64"
CUSTOM_ISO_FILENAME="freebsd-custom.iso"
INSTALLER_CFG=installerconfig.${RELEASE}

# Clean up ISO file if download is interupted
trap "rm -rf $PWD/${ISO_DIR}/${ISO}" SIGHUP SIGINT SIGKILL SIGTERM
# Delete Previous custom layout
trap "rm -rf $CUSTOM_ISO_LAYOUT" SIGHUP SIGINT SIGKILL SIGTERM

function fetch_iso() {
  if [[ ! -d $ISO_DIR ]]; then
    mkdir -p $ISO_DIR
  fi

  echo "==> Fetching ${SHA256SUM}"
  curl -sS -o ${ISO_DIR}/${SHA256SUM} ftp://${MIRROR}/${MIRROR_PATH}/${RELEASE}/${SHA256SUM}

  echo "==> Checking for local copy of $ISO..."
  if [[ -e $ISO_DIR/$ISO ]]; then
    echo "==> Found local copy of $ISO"

  else
      echo "==> Local copy not found."
      echo "==> Fetching ISO from $MIRROR..."
      curl -#S -o ${ISO_DIR}/${ISO} ftp://${MIRROR}/${MIRROR_PATH}/${RELEASE}/${ISO}
      echo "==> Done!"
      echo "==> ${ISO} saved to $ISO_DIR/"

      echo "==> Verifying $ISO with ${SHA256SUM}"

      if [[ "$(sha256 $ISO_DIR/$ISO | cut -f2 -d= | tr -d '[[:space:]]')" == "$(grep "($ISO)" $ISO_DIR/${SHA256SUM} | cut -f2 -d= | tr -d '[[:space:]]')" ]]; then
          echo "==> Checksums match."
      else
          echo "==> Checksums don't match!"
          exit 1
      fi
  fi
}

function create_layout() {
  echo "==> Creating custom ISO Layout"
  if [[ -d $CUSTOM_ISO_LAYOUT ]]; then
      echo "==> Previous layout $CUSTOM_ISO_LAYOUT exists...deleting"
      rm -rf $CUSTOM_ISO_LAYOUT
  fi
  echo "==> Creating $CUSTOM_ISO_LAYOUT"
  mkdir -p $CUSTOM_ISO_LAYOUT

  if [[ ! -d $ISO_MOUNT ]]; then
      echo "==> Creating $ISO_MOUNT ..."
      mkdir $ISO_MOUNT
  fi

  if [[ $(df | grep $ISO_MOUNT) ]]; then
    echo "==> Unmounting previous $ISO_MOUNT..."
    umount $ISO_MOUNT
  fi

  echo "==> Mounting $ISO to $ISO_MOUNT"
  mount -t cd9660 /dev/`mdconfig -f $ISO_DIR/$ISO` $ISO_MOUNT

  echo "==> Copying layout from $ISO_MOUNT to $CUSTOM_ISO_LAYOUT"
  rsync -aq  $ISO_MOUNT/ $CUSTOM_ISO_LAYOUT

  echo "==> Copying $INSTALLER_CFG to $CUSTOM_ISO_LAYOUT"
  cp $INSTALLER_CFG $CUSTOM_ISO_LAYOUT/etc/installerconfig

  echo "==> Enable serial and internal consoles"
  echo "-Dhv" > $CUSTOM_ISO_LAYOUT/boot.config
  echo "cuau0   \"/usr/libexec/getty std.38400\"  xterm   on  secure" >> $CUSTOM_ISO_LAYOUT/etc/ttys

  echo "==> Setting autoboot delay to 5 seconds"
  echo "autoboot_delay=\"5\"" >> $CUSTOM_ISO_LAYOUT/boot/loader.conf

  echo "==> Get network up automatically in the blank VM"
  echo "ifconfig_em0=\"DHCP\"" >> $CUSTOM_ISO_LAYOUT/etc/rc.conf

  echo "==> Remove resolv.conf symlink"
  rm $CUSTOM_ISO_LAYOUT/etc/resolv.conf

  echo "==> Set resolvers in the blank VM"
  echo "nameserver 9.9.9.9" >> $CUSTOM_ISO_LAYOUT/etc/resolv.conf
  echo "nameserver 1.1.1.1" >> $CUSTOM_ISO_LAYOUT/etc/resolv.conf

  echo "==> Unmounting $ISO_MOUNT"
  umount $ISO_MOUNT
}

function create_newiso() {
  echo "==> Getting Volume ID for ${ISO}"
  CUSTOM_ISO_TITLE=$(isoinfo -d -i ${ISO_DIR}/${ISO} | grep "Volume id" | awk '{print $3}')
  echo "==> Volume ID is $CUSTOM_ISO_TITLE"

  echo "==> Preparing NEW ISO"
  mkisofs -J -R -no-emul-boot \
    -V "$CUSTOM_ISO_TITLE" \
    -p "Probably" -b boot/cdboot \
    -o $CUSTOM_ISO_FILENAME $CUSTOM_ISO_LAYOUT
  echo "==> Custom ISO now ready: $CUSTOM_ISO_FILENAME"
}

echo "==> ISO Build Starting!"
fetch_iso
create_layout
create_newiso