####################################################################
# Recover-VM.ps1
#
# Syntax:  Recover-VM.ps1 "<drive:\path\VM_Config_File_as_GUID.xml>" 
#          (Use quotes in the argument)
#
# Example: Recover-VM.ps1 "v:\VirtualMachine1\Virtual Machines\7660AA46-BA41-4171-8820-CDD7C71050A0.xml"
#
# Purpose: Creates Symbolic Links and sets the required permissions
#          to make a Hyper-V Virtual Machine available in Hyper-V
#          Management Console. This script is intended for use in
#          recovery scenario where a Virtual Guests files have been
#          manually moved to another Virtual Server, but the volume
#          drive mappings are the same, only.
#          The methodology that this script employs is as discussed
#          in the below blog.
#          It should be noted that once this script has been used
#          the Virtual Guest is in an unsupported state and should
#          be exported and re-imported in Hyper-V Manager to
#          correctly set all the Virtual Machines permissions.
#
# Params:  The drive, folder and filename of the Virtual Machine
#          xml configuration file.
#
# Req:     Windows 2008 or above, Powershell V2, mklink, icacls.
#          run "set-executionpolicy remotesigned" in Powershell
#
# Ref:     http://blogs.msdn.com/b/robertvi/archive/2008/12/19/howto-manually-add-a-vm-configuration-to-hyper-v.aspx
#          http://blogs.technet.com/b/carlh
#
# Author:  CarlH
#
# Myself or my employer do not warantee this script in any way and use
# of it is entirely at the users own risk. The script is intended to
# Recover Virtual Machines only in a recovery scenario, and such VM's
# should be exported and imported onto the Hyper-V server to ensure
# a supported state.
#
# Version: 1.0 - First cut
#
####################################################################

Param($VMConfigFile)

Write-Host ""
Write-Host "---------------Recover-VM Script Start"
$SystemDrive = (Get-item env:systemdrive).Value
$VMFolder = (Get-Item $VMConfigFile).directoryname
$VMFolder = (Get-Item $VMFolder).parent
$VMFolderName = $VMFolder.fullname
Write-Host ""

#Read from the VM Configuration file. VM GUID for Service account. VM Name.
Write-Host "---------------Reading VM Configuration File"
[xml]$VMXML = Get-Content $VMConfigFile
$VMSvcAccount = $VMXML.configuration.properties.global_id."#text"
$VMName = $VMXML.configuration.properties.name."#text"
Write-Host "---------------Completed reading VM Configuration File"
Write-Host ""

#This function takes a file name including the full path as a ThisItem string parameter and gets the current ACL.
#It adds the VM Service account to the current ACL and then Sets the new ACL
function SetACL
{
    Param($ThisItem)
    Write-Host ""
    Write-Host "---------------Setting Permissions for $ThisItem"
    Write-Host ""
    $Acl = Get-Acl $ThisItem
    $AccessRule = New-Object  system.security.accesscontrol.filesystemaccessrule("NT VIRTUAL MACHINE\$VMSvcAccount","FullControl","Allow")
    $Acl.SetAccessRule($AccessRule)
    Set-Acl $ThisItem $Acl   
    Write-Host ""
    Write-Host "---------------Finished Permissions for $ThisItem"
}

#This Function uses the cmd line utility mklink to create a symbolic link of the physical file passed to it in the HardFile parameter as a string
#The LinkLocation string parameter defines what folder the link will be created in under systemdrive\programdata\Microsoft\Windows\Hyper-V\
function MkSymLink
{
    Param($HardFile, $LinkLocation)
    Write-Host ""
    Write-Host "---------------Creating Symbolic Link for $HardFile"
    Write-Host ""
    $LinkFile = (get-item $HardFile).name
    #Write-Host "%systemdrive%\programdata\Microsoft\Windows\Hyper-V\$LinkLocation\$LinkFile" $HardFile
    cmd /c mklink "%systemdrive%\programdata\Microsoft\Windows\Hyper-V\$LinkLocation\$LinkFile" $HardFile
    Write-Host ""
    Write-Host "---------------Finished Symbolic Link for $HardFile"
}

#Get the VM config xml Fully Qualified Name and pass it to the MKSymLink function with the location for the for storing the Symbolic Link
$VMFileString = (get-item $VMConfigFile).name
MkSymLink -HardFile $VMConfigFile -LinkLocation "Virtual Machines"

#Call the SetACL function and pass it the FQN of the Symbolic Link to which we need to set the ACL 
$ConfigFileSymLink = "$SystemDrive\programdata\Microsoft\Windows\Hyper-V\Virtual Machines\$VMFileString"
SetACL -ThisItem $ConfigFileSymLink

#Get the FQN of the boot VHD from the VM Config xml file passed into the script. Then pass this to the SetACL function 
$VMVHDBootFile = $VMXML.configuration.'_83f8638b-8dca-4152-9eda-2ca8b33039b4_'.controller0.drive0.pathname."#text"
SetACL -ThisItem $VMVHDBootFile

#Build a string that defines the VM Service Account and use it with the cmd line utility icacls to set the permissions for all folders and files of the VM 
Write-Host ""
Write-Host "---------------Setting Permissions for Folder $VMFolderName"
Write-Host ""
$VMSvcAccountFQN = 'NT VIRTUAL MACHINE\'+$VMSvcAccount
cmd /c icacls ""$VMFolderName"" /T /grant ""$VMSvcAccountFQN""':(F)'
Write-Host ""
Write-Host "---------------Finished Permissions for Folder $VMFolderName"


#Discover if there are any Snapshots. If so, for each one, create a Symbolic link for each by passing the FQN of the snapshot and snapsot link location
#Also, call SetACL to set permissions for the VM Services account on the Symbolic Link
foreach ($Thing in (Get-ChildItem $VMFolderName))
{
    If ($Thing.name -eq "Snapshots")
    {
    $SnapshotsFolder = $Thing.Fullname
        foreach ($Thing2 in (Get-ChildItem $SnapshotsFolder))
        {        
            If ($Thing2.extension -eq ".xml")
            {
            $VMSnapshotFileString = $Thing2.name
            MkSymLink -HardFile $Thing2.fullname -LinkLocation "Snapshots"
            $SnapshotFileSymLink = "$SystemDrive\programdata\Microsoft\Windows\Hyper-V\Snapshots\$VMSnapshotFileString"
            SetACL -ThisItem $SnapshotFileSymLink
            }
        }
    }
}
Write-Host ""
Write-Host "----------------End Script Recover-VM.ps1"