Fetch containeros linux headers

fetch-linux-headers.sh

#!/bin/bash

LSB_FILE="/mnt/root/etc/lsb-release"
OS_RELEASE_FILE="/mnt/root/etc/os-release"

generate_headers()
{
  echo "Generating kernel headers"
  cd ${SOURCES_DIR}
  zcat /proc/config.gz > .config
  make oldconfig > /dev/null
  make prepare > /dev/null
}

fetch_cos_linux_sources()
{
  if [ ! -e "${SOURCES_DIR}/.fetched" ];then
    echo "Fetching upstream kernel sources."
    mkdir -p ${SOURCES_DIR}
    curl -s "https://storage.googleapis.com/cos-tools/${BUILD_ID}/kernel-src.tar.gz" | tar -xzf - -C ${SOURCES_DIR}
    touch "${SOURCES_DIR}/.fetched"
  fi
}

install_cos_linux_headers()
{
  if grep -q CHROMEOS_RELEASE_VERSION ${LSB_FILE};then
    BUILD_ID=$(grep CHROMEOS_RELEASE_VERSION ${LSB_FILE} | cut -d = -f 2)
    SOURCES_DIR="/usr/src/linux-lakitu-${BUILD_ID}"

    if [ ! -e "${SOURCES_DIR}/.installed" ];then
      echo "Installing kernel headers for for COS build ${BUILD_ID}"
      fetch_cos_linux_sources
      generate_headers
      touch "${SOURCES_DIR}/.installed"
    fi
  fi
}

distro=$(grep ^NAME ${OS_RELEASE_FILE} | cut -d = -f 2)

case $distro in
  *"Container-Optimized OS"*)
    install_cos_linux_headers
    ;;
  *)
    echo "WARNING: ${distro} is not a supported distro, cannot install headers, ensure they are installed to /lib/modules"
esac