inspec/lib/resources/kernel_parameter.rb

# encoding: utf-8
# author: Christoph Hartmann
# license: All rights reserved

# Verifies if a kernel parameter is set
# describe kernel_parameter('net.ipv4.conf.all.forwarding') do
#   its(:value) { should eq 0 }
# end
class KernelParameter < Inspec.resource(1)
  name 'kernel_parameter'

  def initialize(parameter = nil)
    @parameter = parameter

    # this resource is only supported on Linux
    return skip_resource 'The `kernel_parameter` resource is not supported on your OS.' if !inspec.os.linux?
  end

  def value
    cmd = inspec.command("/sbin/sysctl -q -n #{@parameter}")
    return nil if cmd.exit_status != 0
    # remove whitespace
    cmd = cmd.stdout.chomp.strip
    # convert to number if possible
    cmd = cmd.to_i if cmd.match(/^\d+$/)
    cmd
  end

  def to_s
    "Kernel Parameter #{@parameter}"
  end
end

# for compatability with serverspec
# this is deprecated syntax and will be removed in future versions
class LinuxKernelParameter < KernelParameter
  name 'linux_kernel_parameter'

  def initialize(parameter)
    super(parameter)
  end

  def value
    deprecated
    super()
  end

  def deprecated
    warn '[DEPRECATION] `linux_kernel_parameter(parameter)` is deprecated.  Please use `kernel_parameter(parameter)` instead.'
  end

  def to_s
    "Kernel Parameter #{@parameter}"
  end
end