helper functions for squeak.sh launcher script

helpers.sh

CONF_FILE="/etc/security/limits.d/squeak.conf"

# Ensure that Linux kernel is newer than 2.6.12 which is required for the heartbeat thread
ensure_kernel() {
  local kernel_release="$(uname -r)"
  local re='[^0-9]*\([0-9]*\)[.]\([0-9]*\)[.]\([0-9]*\)\([0-9A-Za-z-]*\)'
  local major=$(echo "${kernel_release}" | sed -e "s#${re}#\1#")
  local minor=$(echo "${kernel_release}" | sed -e "s#${re}#\2#")
  local patch=$(echo "${kernel_release}" | sed -e "s#${re}#\3#")
  # 2.6.12
  local min_major="2"
  local min_minor="6"
  local min_patch="12"

  if [[ "${major}" -lt "${min_major}" ]] || \
     [[ "${major}" -le "${min_major}" && "${major}" -lt "${min_minor}" ]] || \
     [[ "${major}" -le "${min_major}" && "${major}" -le "${min_minor}" && "${patch}" -lt "${min_patch}" ]]; then
    showerror "Linux kernel ($(uname -r)) needs to be newer than ${min_major}.${min_minor}.${min_patch}."
    exit 1
  fi
}

# Ensure that the $CONF_FILE configuration file exists and help to create one
ensure_conf_file() {
  local user_input
  if ! [[ -f "${CONF_FILE}" ]]; then
    read -p "${CONF_FILE} is missing. Do you want to create one?
This operation requires sudo permissions. (y/N): " user_input
    if [[ "${user_input}" = "y" ]]; then
      echo "You may be asked to enter your password..."
      sudo tee -a "${CONF_FILE}" > /dev/null <<END
*       hard    rtprio  2
*       soft    rtprio  2
END
      echo "Done! Please log out and log back in before you try again."
    else
      echo "Operation cancelled."
    fi
    exit 0
  fi
}