Problems reading in from array

PowerShell Help
1

Hi,

I’m having some issue with following script:

$Computers = get-adcomputer -filter * -searchbase "ou=computers,dc=domain,dc=com" | foreach-object {$_.name}

foreach ($computer in $Computers)

{get-windowskey -targets $computer}

Get-windowskey is a function I have loaded into my environment which takes the name of a pc, stated with the param -targets, and returns the Windows version and product key. When I run the above script with hard coded $Computers, it runs great. However, running the above gives me the below error, any advice?

Thanks in advance

Cannot convert value "\\CAND8TQ14J\root\default:stdRegProv" to type "System.Management.ManagementClass". Error: "The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)" At C:\Powershell\GetProductKeyFunction.ps1:11 char:9 + $wmi = [WMIClass]"\\$target\root\default:stdRegProv" + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : InvalidArgument: (:) [], RuntimeException + FullyQualifiedErrorId : InvalidCastToWMIClass

You cannot call a method on a null-valued expression.
At C:\Powershell\GetProductKeyFunction.ps1:12 char:9

  •     $data = $wmi.GetBinaryValue($hklm,$regPath,$regValue)

  •     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    • CategoryInfo : InvalidOperation: (:slight_smile: , RuntimeException
    • FullyQualifiedErrorId : InvokeMethodOnNull

Cannot index into a null array.
At C:\Powershell\GetProductKeyFunction.ps1:13 char:9

  •     $binArray = ($data.uValue)[52..66]

  •     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    • CategoryInfo : InvalidOperation: (:slight_smile: , RuntimeException
    • FullyQualifiedErrorId : NullArray
2

Your ForEach-Object is a bit of an odd way to do what you’re after…

Get-ADComputer -filter * | Select -Expand Name

Is a bit more common.

The errors are coming from inside your Get-WindowsKey function. Without seeing it, it’s a bit difficult to guess what might be wrong. But, the error “RPC server is unavailable” suggests that it isn’t connecting to the computer listed in $target.

I suspect you might be able to query the same info more easily by using the Win32_OperatingSystem class, too. That’d eliminate needing to mess with the registry, if the info you need is in there.

3

Hey Don, thank you for your response. I’ll make that amendment to the script, thanks for the suggestion.

I noticed as soon as I posted that the error looked to be stemming from the function itself. It’s one I grabbed from the net.

Thanks for your time and insight.

Here is the function:

function Get-WindowsKey {
## function to retrieve the Windows Product Key from any PC
## by Jakob Bindslet (jakob@bindslet.dk)
param ($targets = “.”)
$hklm = 2147483650
$regPath = “Software\Microsoft\Windows NT\CurrentVersion”
$regValue = “DigitalProductId”
Foreach ($target in $targets) {
$productKey = $null
$win32os = $null
$wmi = [WMIClass]“\$target\root\default:stdRegProv”
$data = $wmi.GetBinaryValue($hklm,$regPath,$regValue)
$binArray = ($data.uValue)[52…66]
$charsArray = “B”,“C”,“D”,“F”,“G”,“H”,“J”,“K”,“M”,“P”,“Q”,“R”,“T”,“V”,“W”,“X”,“Y”,“2”,“3”,“4”,“6”,“7”,“8”,“9”
## decrypt base24 encoded binary data
For ($i = 24; $i -ge 0; $i–) {
$k = 0
For ($j = 14; $j -ge 0; $j–) {
$k = $k * 256 -bxor $binArray[$j]
$binArray[$j] = [math]::truncate($k / 24)
$k = $k % 24
}
$productKey = $charsArray[$k] + $productKey
If (($i % 5 -eq 0) -and ($i -ne 0)) {
$productKey = “-” + $productKey
}
}
$win32os = Get-WmiObject Win32_OperatingSystem -computer $target
$obj = New-Object Object
$obj | Add-Member Noteproperty Computer -value $target
$obj | Add-Member Noteproperty Caption -value $win32os.Caption
$obj | Add-Member Noteproperty CSDVersion -value $win32os.CSDVersion
$obj | Add-Member Noteproperty OSArch -value $win32os.OSArchitecture
$obj | Add-Member Noteproperty BuildNumber -value $win32os.BuildNumber
$obj | Add-Member Noteproperty RegisteredTo -value $win32os.RegisteredUser
$obj | Add-Member Noteproperty ProductID -value $win32os.SerialNumber
$obj | Add-Member Noteproperty ProductKey -value $productkey
$obj
}
}

4

Looks like all you really need is some error handling. If the ([WMIClass]“\$target\root\default:stdRegProv”) expression throws an error such as RPC Server is Unavailable, there’s really no point in trying to run the rest of the code for that particular target.

5

Thanks Dave, I’ll take a look at what is needed and how to implement it. Price you pay for using someone elses code I guess!

Thanks again.

6

Just to give an update, I managed to get it working. I changed the param for the function to except get-content, and added some error handling. Working out the rest of the kinks, but pretty happy with what I have so far. Thanks to you both for pointing me in the right direction.

Regards,
Doug