# encoding: utf-8

require 'hashie/mash'

module Inspec::Resources
  class Virtualization < Inspec.resource(1)
    name 'virtualization'
    supports platform: 'linux'
    desc 'Use the virtualization InSpec audit resource to test the virtualization platform on which the system is running'
    example <<~EXAMPLE
      describe virtualization do
        its('system') { should eq 'docker' }
      end

      describe virtualization do
        its('role') { should eq 'guest' }
      end

      control 'test' do
        describe file('/var/tmp/foo') do
          it { should be_file }
        end
        only_if { virtualization.system == 'docker' }
      end
    EXAMPLE

    def initialize
      @virtualization_data = Hashie::Mash.new
      collect_data_linux
    end

    # add helper methods for easy access of properties
    # allows users to use virtualization.role, virtualization.system
    %w{role system}.each do |property|
      define_method(property.to_sym) do
        @virtualization_data[property.to_sym]
      end
    end

    def params
      collect_data_linux
    end

    def to_s
      'Virtualization Detection'
    end

    private

    def lxc_version_exists?
      inspec.command('lxc-version').exist?
    end

    def docker_exists?
      inspec.command('docker').exist?
    end

    def nova_exists?
      inspec.command('nova').exist?
    end

    # Detect Xen
    # /proc/xen is an empty dir for EL6 + Linode Guests + Paravirt EC2 instances
    # Notes:
    # - cpuid of guests, if we could get it, would also be a clue
    # - may be able to determine if under paravirt from /dev/xen/evtchn (See OHAI-253)
    # - Additional edge cases likely should not change the above assumptions
    #   but rather be additive - btm
    def detect_xen
      # This file should exist on most Xen systems, normally empty for guests
      return false unless inspec.file('/proc/xen/capabilities').exist?
      @virtualization_data[:system] = 'xen'
      if inspec.file('/proc/xen/capabilities').content =~ /control_d/i
        @virtualization_data[:role] = 'host'
      else
        @virtualization_data[:role] = 'guest'
      end

      true
    end

    # Detect Virtualbox from kernel module
    def detect_virtualbox
      return false unless inspec.file('/proc/modules').exist?
      modules = inspec.file('/proc/modules').content
      if modules =~ /^vboxdrv/
        Inspec::Log.debug('Plugin Virtualization: /proc/modules contains vboxdrv. Detecting as vbox host')
        @virtualization_data[:system] = 'vbox'
        @virtualization_data[:role] = 'host'
      elsif modules =~ /^vboxguest/
        Inspec::Log.debug('Plugin Virtualization: /proc/modules contains vboxguest. Detecting as vbox guest')
        @virtualization_data[:system] = 'vbox'
        @virtualization_data[:role] = 'guest'
      else
        return false
      end
      true
    end

    # if nova binary is present we're on an openstack host
    def detect_openstack
      return false unless nova_exists?
      @virtualization_data[:system] = 'openstack'
      @virtualization_data[:role] = 'host'
      true
    end

    # Detect paravirt KVM/QEMU from cpuinfo, report as KVM
    def detect_kvm_from_cpuinfo
      return false unless inspec.file('/proc/cpuinfo').content =~ /QEMU Virtual CPU|Common KVM processor|Common 32-bit KVM processor/
      @virtualization_data[:system] = 'kvm'
      @virtualization_data[:role] = 'guest'
      true
    end

    # Detect KVM systems via /sys
    # guests will have the hypervisor cpu feature that hosts don't have
    def detect_kvm_from_sys
      return false unless inspec.file('/sys/devices/virtual/misc/kvm').exist?
      @virtualization_data[:system] = 'kvm'
      if inspec.file('/proc/cpuinfo').content =~ /hypervisor/
        @virtualization_data[:role] = 'guest'
      else
        @virtualization_data[:role] = 'host'
      end
      true
    end

    # Detect OpenVZ / Virtuozzo.
    # http://wiki.openvz.org/BC_proc_entries
    def detect_openvz
      if inspec.file('/proc/bc/0').exist?
        @virtualization_data[:system] = 'openvz'
        @virtualization_data[:role] = 'host'
      elsif inspec.file('/proc/vz').exist?
        @virtualization_data[:system] = 'openvz'
        @virtualization_data[:role] = 'guest'
      else
        return false
      end
      true
    end

    # Detect Parallels virtual machine from pci devices
    def detect_parallels
      return false unless inspec.file('/proc/bus/pci/devices').content =~ /1ab84000/
      @virtualization_data[:system] = 'parallels'
      @virtualization_data[:role] = 'guest'
      true
    end

    # Detect Linux-VServer
    def detect_linux_vserver
      return false unless inspec.file('/proc/self/status').exist?
      proc_self_status = inspec.file('/proc/self/status').content
      vxid = proc_self_status.match(/^(s_context|VxID):\s*(\d+)$/)
      return false unless vxid && vxid[2]
      @virtualization_data[:system] = 'linux-vserver'
      if vxid[2] == '0'
        @virtualization_data[:role] = 'host'
      else
        @virtualization_data[:role] = 'guest'
      end
      true
    end

    # Detect LXC/Docker
    #
    # /proc/self/cgroup will look like this inside a docker container:
    # <index #>:<subsystem>:/lxc/<hexadecimal container id>
    #
    # /proc/self/cgroup could have a name including alpha/digit/dashes
    # <index #>:<subsystem>:/lxc/<named container id>
    #
    # /proc/self/cgroup could have a non-lxc cgroup name indicating other uses
    # of cgroups.  This is probably not LXC/Docker.
    # <index #>:<subsystem>:/Charlie
    #
    # A host which supports cgroups, and has capacity to host lxc containers,
    # will show the subsystems and root (/) namespace.
    # <index #>:<subsystem>:/
    #
    # Full notes, https://tickets.opscode.com/browse/OHAI-551
    # Kernel docs, https://www.kernel.org/doc/Documentation/cgroups
    def detect_lxc_docker
      return false unless inspec.file('/proc/self/cgroup').exist?
      cgroup_content = inspec.file('/proc/self/cgroup').content
      if cgroup_content =~ %r{^\d+:[^:]+:/(lxc|docker)/.+$} ||
          cgroup_content =~ %r{^\d+:[^:]+:/[^/]+/(lxc|docker)-.+$} # rubocop:disable Layout/MultilineOperationIndentation
        @virtualization_data[:system] = $1 # rubocop:disable Style/PerlBackrefs
        @virtualization_data[:role] = 'guest'
      elsif lxc_version_exists? && cgroup_content =~ %r{\d:[^:]+:/$}
        # lxc-version shouldn't be installed by default
        # Even so, it is likely we are on an LXC capable host that is not being used as such
        # So we're cautious here to not overwrite other existing values (OHAI-573)
        unless @virtualization_data[:system] && @virtualization_data[:role]
          @virtualization_data[:system] = 'lxc'
          @virtualization_data[:role] = 'host'
        end
      else
        return false
      end
      true
    end

    def detect_docker
      return false unless inspec.file('/.dockerenv').exist? || inspec.file('/.dockerinit').exist?
      @virtualization_data[:system] = 'docker'
      @virtualization_data[:role] = 'guest'
      true
    end

    # Detect LXD
    # See https://github.com/lxc/lxd/blob/master/doc/dev-lxd.md
    def detect_lxd
      if inspec.file('/dev/lxd/sock').exist?
        @virtualization_data[:system] = 'lxd'
        @virtualization_data[:role] = 'guest'
      elsif inspec.file('/var/lib/lxd/devlxd').exist?
        @virtualization_data[:system] = 'lxd'
        @virtualization_data[:role] = 'host'
      else
        return false
      end
      true
    end

    def collect_data_linux # rubocop:disable Metrics/PerceivedComplexity, Metrics/CyclomaticComplexity
      # This avoids doing multiple detections in a single test
      return unless @virtualization_data.empty?

      # each detect method will return true if it matched and was successfully
      # able to populate @virtualization_data with stuff.
      return if detect_xen
      return if detect_virtualbox
      return if detect_openstack
      return if detect_kvm_from_cpuinfo
      return if detect_kvm_from_sys
      return if detect_openvz
      return if detect_parallels
      return if detect_linux_vserver
      return if detect_lxc_docker
      return if detect_docker
      return if detect_lxd
    end
  end
end