Powershell - How to use result of one WMI query in another WMI query? - powershell

Question

Trying to list the user permissions of shares on a server, where the share's path has a common file path element in it.
I have a script that successfully uses the Win32_LogicalShareSecuritySetting WMI class to enumerate the share permissions of all the shares on the server, but unfortunately that class does not have the file path of the share as an attribute... I can use the Win32_Share class and do something like:
$FinShares = Get-WmiObject -Class Win32_Share -Filter "Path LIKE '%Finance%'" -ComputerName $computername
and I do get a list of the desired shares. But how to pass that list into the next Get-WmiObject statement? I've tried something like:
$FinShares = (Get-WmiObject -Class Win32_Share -Filter "Path LIKE '%Finance%'" -ComputerName $computername | Select-Object Name)
foreach ($ShareInst in $FinShares)
{
$FinShareSS = Get-WmiObject -Class Win32_LogicalShareSecuritySetting -Filter "Name = '$ShareInst'" -ComputerName $computername
$SecurityDescriptor = $FinShareSS.GetSecurityDescriptor()
(...)
When I try that, the variable $FinShareSS remains null... Can someone give me a pointer (or some kind of better way altogether) as to how I can do this?

Answer 1

The problem is your filter using $ShareInst; it's not working, because it is not returning the Name like you expect. Try just putting "$ShareInst" inside your foreach loop; you should see things like:
\COMPUTERNAME\root\cimv2:Win32_Share.Name="ADMIN$"
Which is the WMI object's PATH, not it's name. What you have in $ShareInst is an object of type System.Management.ManagementObject#root\cimv2\Win32_Share, not a string. When you put that variable inside double quotes, PowerShell expands the variable into a string using the objects .ToString() method. Which in the case of this Win32_Share object, returns the PATH of the object, not the name.
So basically you just need to get the actual name string in the -Filter string, so that it will actually return the share security object you are looking for. There are several ways to do this:
Embed the Property name in the string, like so:
-Filter "Name = '$($ShareInst.Name)'"
The $() wrapper tells PowerShell to evaluate the .Name property before expanding the variable into that long PATH value, so you get just the short name you're looking for.
If you just need the Win32_Share objects for the Name, then you can just change the foreach line to look like this:
foreach ($ShareInst in ($FinShares | Select-Object -ExpandProperty Name))
The -ExpandProperty parameter of the Select-Object tells PowerShell to get the Name property of each object and just return that, instead of the full object. Now $ShareInst will be just the name of the Win32_Share, so you can leave your filter as-is.
There are any number of other ways to resolve this issue, but those two seem the most straight-forward to me.