windows-amd64-prebuilt-libr.../vcpkg/scripts/cleanEnvironmentHelper.ps1
2020-10-10 14:36:42 +02:00

53 lines
2.3 KiB
PowerShell

# Capture environment variables for the System and User. Also add some special/built-in variables.
# These will be used to synthesize a clean environment
$specialEnvironmentMap = @{ "SystemDrive"=$env:SystemDrive; "SystemRoot"=$env:SystemRoot; "UserProfile"=$env:UserProfile; "TMP"=$env:TMP } # These are built-in and not set in the registry
$machineEnvironmentMap = [Environment]::GetEnvironmentVariables('Machine') # HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment
$userEnvironmentMap = [Environment]::GetEnvironmentVariables('User') # HKEY_CURRENT_USER\Environment
# Identify the keySet of environment variable names
$nameSet = ($specialEnvironmentMap.Keys + $machineEnvironmentMap.Keys + $userEnvironmentMap.Keys) | Sort-Object | Select-Object -Unique
# Any environment variable in the $nameSet should be restored to its original value
foreach ($name in $nameSet)
{
if ($specialEnvironmentMap.ContainsKey($name))
{
[Environment]::SetEnvironmentVariable($name, $specialEnvironmentMap[$name], 'Process')
continue;
}
# PATH needs to be concatenated as it has values in both machine and user environment. Any other values should be set.
if ($name -eq 'path')
{
$pathValuePartial = @()
# Machine values before user values
$pathValuePartial += $machineEnvironmentMap[$name] -split ';'
$pathValuePartial += $userEnvironmentMap[$name] -split ';'
$pathValue = $pathValuePartial -join ';'
[Environment]::SetEnvironmentVariable($name, $pathValue, 'Process')
continue;
}
if ($userEnvironmentMap.ContainsKey($name))
{
[Environment]::SetEnvironmentVariable($name, $userEnvironmentMap[$name], 'Process')
continue;
}
if ($machineEnvironmentMap.ContainsKey($name))
{
[Environment]::SetEnvironmentVariable($name, $machineEnvironmentMap[$name], 'Process')
continue;
}
throw "Unreachable: Unknown variable $name"
}
# Any environment variable NOT in the $nameSet should be removed
$processEnvironmentMap = [Environment]::GetEnvironmentVariables('Process')
$variablesForRemoval = $processEnvironmentMap.Keys | Where-Object {$nameSet -notcontains $_}
foreach ($name in $variablesForRemoval)
{
[Environment]::SetEnvironmentVariable($name, $null, 'Process')
}