F #5260: Add device mapper for LXC

It allows to use LVM and RDM drivers.

src/vmm_mad/remotes/lib/lxc/opennebula_vm.rb

@@ -25,6 +25,7 @@ require 'storageutils'
 require 'qcow2'
 require 'raw'
 require 'rbd'
+require 'device'
 
 require_relative '../lib/xmlparser'
 require_relative '../lib/opennebula_vm'
@@ -339,6 +340,8 @@ class Disk
             Qcow2Mapper.new
         elsif @xml['DISK_TYPE'].downcase == 'rbd'
             RBDMapper.new(self)
+        elsif @xml['DISK_TYPE'].downcase == 'block'
+            DeviceMapper.new
         else
             RawMapper.new
         end

src/vmm_mad/remotes/lib/lxc/storage/mappers/device.rb

@@ -0,0 +1,32 @@
+#!/usr/bin/ruby
+
+$LOAD_PATH.unshift File.dirname(__FILE__)
+
+require 'command'
+
+# Mapping utilities for raw devices (e.g LVM, RDM)
+class DeviceMapper
+
+    # Maps raw image file to linux loopdevice
+    def map(disk)
+        ds_path = source(disk)
+
+        if File.symlink?(ds_path)
+            return File.readlink(ds_path) # Raw device path
+        end
+
+        nil
+    end
+
+    def unmap(_device)
+        true
+    end
+
+    private
+
+    # Returns the source file for the disk
+    def source(disk)
+        "#{disk.sysds_path}/#{disk.vm_id}/disk.#{disk.id}"
+    end
+
+end