Remove-DriveMapping prototype

Author: stevenmcohn

Modules/Scripts/New-DriveMapping.ps1

@@ -26,15 +26,15 @@ New label to apply to the source drive; default it to retain the current label.
 
 using namespace System.IO
 
-[CmdletBinding(SupportsShouldProcess = $true)]
+[CmdletBinding(SupportsShouldProcess=$true)]
 
 param (
-	[Parameter(Mandatory=$true, Position=0, HelpMessage='Drive letter must not be currently used')]
+	[Parameter(Mandatory=$true, Position=0, HelpMessage='Drive letter must not be in use')]
 	[ValidateLength(1, 1)]
 	[ValidatePattern('[A-Z]')]
 	[ValidateScript({
-		if (Get-Volume $_ -ErrorAction 'SilentlyContinue') {
-			Throw 'Cannot reuse a physical drive letter'
+		if ((Get-ItemPropertyValue "Registry::$DOSDevicesKey" -Name ('{0}:' -f $DriveLetter) -ErrorAction 'SilentlyContinue') -eq $null) {
+			Throw 'DriveLetter does not specify a mapped drive'
 		}
 		$true
 	})]

Modules/Scripts/Remove-DriveMapping.ps1

@@ -0,0 +1,111 @@
+<#
+.SYNOPSIS
+Remove a persistent mapping of a folder.
+
+.PARAMETER DriveLetter
+The mapped drive letter to remove.
+
+.PARAMETER Force
+Force using SourceDriveLabel, provided DriverLetter is the last mapping
+to the source drive.
+
+.PARAMETER Reboot
+If true then reboot system; default is true.
+
+.PARAMETER SourceDriveLabel
+New label to apply to the source drive; default it to retain the current label.
+This is only applied if DriveLetter is the last mapping to the source drive.
+#>
+
+using namespace System.IO
+
+[CmdletBinding(SupportsShouldProcess=$true)]
+
+param (
+	[Parameter(Mandatory=$true, Position=0, HelpMessage='Drive letter must be a mapped drive')]
+	[ValidateLength(1, 1)]
+	[ValidatePattern('[A-Z]')]
+	[ValidateScript({
+		if ((Get-ItemPropertyValue "Registry::$DOSDevicesKey" -Name ('{0}:' -f $_) -ErrorAction 'SilentlyContinue') -eq $null) {
+			Throw 'Drive letter not found or does not represent a mapped drive'
+		}
+		$true
+	})]
+	[string] $DriveLetter,
+
+	[string] $SourceDriveLabel,
+
+	[switch] $Reboot,
+	[switch] $Force
+	)
+
+Begin
+{
+	$DriveIconsKey = 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons'
+	$DOSDevicesKey = 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices'
+
+	function UnmapDriveLetter ()
+	{
+		# remove mapping
+		if ($WhatIfPreference) {
+			Write-Host "Remove-ItemProperty ""$DOSDevicesKey"" -Name ""${DriveLetter}:"" -Force" -ForegroundColor DarkYellow
+		} else {
+			Write-Verbose "Remove-ItemProperty ""$DOSDevicesKey"" -Name ""${DriveLetter}:"" -Force"
+			Remove-ItemProperty "$DOSDevicesKey" -Name "${DriveLetter}:" -Force | Out-Null
+		}
+		Write-Verbose 'removed persistent mapping'
+
+		# remove volume label for mapped drive
+		if ($WhatIfPreference) {
+			Write-Host "Remove-Item ""$DriveIconsKey\$DriveLetter"" -Recurse -Force" -ForegroundColor DarkYellow
+		} else {
+			Write-Verbose "Remove-Item ""$DriveIconsKey\$DriveLetter"" -Recurse -Force"
+			if (Test-Path "$DriveIconsKey\$DriveLetter") {
+				Remove-Item -Path "$DriveIconsKey\$DriveLetter" -Recurse -Force | Out-Null
+			}
+		}
+		Write-Verbose 'removed mapped volume label'
+
+		# remove volume label for source drive
+		if ($WhatIfPreference) {
+			Write-Host "Remove-Item ""$DriveIconsKey\$sourceLetter"" -Recurse -Force" -ForegroundColor DarkYellow
+		} else {
+			Write-Verbose "Remove-Item ""$DriveIconsKey\$sourceLetter"" -Recurse -Force"
+			if (Test-Path "$DriveIconsKey\$sourceLetter") {
+				Remove-Item "$DriveIconsKey\$sourceLetter" -Recurse -Force | Out-Null
+			}
+		}
+		Write-Verbose 'removed source drive volume label'
+
+		# restore volume label
+		if ($WhatIfPreference) {
+			Write-Host "set label of $sourceLetter drive to $label" -ForegroundColor DarkYellow
+		} else {
+			Write-Verbose "set label of $sourceLetter drive to $label"
+			Set-Volume -DriveLetter $sourceLetter -NewFileSystemLabel $label
+		}
+		Write-Verbose 'set label of source drive'
+	}
+}
+Process
+{
+	if (!$SourceDriveLabel -and (Test-Path "$DriveIconsKey\$DriveLetter")) {
+		$SourceDriveLabel = (Get-ItemPropertyValue "$DriveIconsKey\$sourceLetter\DefaultLabel" -Name '(Default)' -ErrorAction 'SilentlyContinue')
+	}
+
+	if (!$SourceDriveLabel) {
+		$SourceDriveLabel = if ($DriveLetter -eq ($env:HOMEDRIVE)[0]) { 'System' } else { 'Data' }
+	}
+
+	UnmapDriveLetter
+
+	if ($Reboot -or !$PSBoundParameters.ContainsKey('Reboot'))
+	{
+		# must reboot in order for this to take effect
+		if ($WhatIfPreference) {
+			Write-Host 'Restart-Computer -Force -Timeout 0' -ForegroundColor DarkYellow
+		} else {
+			Restart-Computer -Force -Timeout 0
+		}
+	}
+}