Make Start-Job throw terminating exception when -RunAs32 is specified in 64-bit pwsh (#9143)

src/System.Management.Automation/engine/hostifaces/PowerShellProcessInstance.cs

@@ -48,28 +48,6 @@ namespace System.Management.Automation.Runspaces
         /// <param name="useWow64"></param>
         public PowerShellProcessInstance(Version powerShellVersion, PSCredential credential, ScriptBlock initializationScript, bool useWow64)
         {
-            string psWow64Path = PwshExePath;
-
-            if (useWow64)
-            {
-                string procArch = Environment.GetEnvironmentVariable("PROCESSOR_ARCHITECTURE");
-
-                if (!string.IsNullOrEmpty(procArch) && (procArch.Equals("amd64", StringComparison.OrdinalIgnoreCase) ||
-                                                        procArch.Equals("ia64", StringComparison.OrdinalIgnoreCase)))
-                {
-                    psWow64Path = PwshExePath.ToLowerInvariant().Replace("\\system32\\", "\\syswow64\\");
-
-                    if (!File.Exists(psWow64Path))
-                    {
-                        string message =
-                            PSRemotingErrorInvariants.FormatResourceString(
-                                RemotingErrorIdStrings.IPCWowComponentNotPresent,
-                                psWow64Path);
-                        throw new PSInvalidOperationException(message);
-                    }
-                }
-            }
-
             string processArguments = " -s -NoLogo -NoProfile";
 
             if (initializationScript != null)
@@ -88,7 +66,7 @@ namespace System.Management.Automation.Runspaces
             // to 'false' in our use, we can ignore the 'WindowStyle' setting in the initialization below.
             _startInfo = new ProcessStartInfo
             {
-                FileName = useWow64 ? psWow64Path : PwshExePath,
+                FileName = PwshExePath,
                 Arguments = processArguments,
                 UseShellExecute = false,
                 RedirectStandardInput = true,

src/System.Management.Automation/engine/remoting/commands/StartJob.cs

@@ -481,20 +481,13 @@ namespace Microsoft.PowerShell.Commands
         private ScriptBlock _initScript;
 
         /// <summary>
-        /// Launces the background job as a 32-bit process. This can be used on
+        /// Launches the background job as a 32-bit process. This can be used on
         /// 64-bit systems to launch a 32-bit wow process for the background job.
         /// </summary>
         [Parameter(ParameterSetName = StartJobCommand.FilePathComputerNameParameterSet)]
         [Parameter(ParameterSetName = StartJobCommand.ComputerNameParameterSet)]
         [Parameter(ParameterSetName = StartJobCommand.LiteralFilePathComputerNameParameterSet)]
-        public virtual SwitchParameter RunAs32
-        {
-            get { return _shouldRunAs32; }
-
-            set { _shouldRunAs32 = value; }
-        }
-
-        private bool _shouldRunAs32;
+        public virtual SwitchParameter RunAs32 { get; set; }
 
         /// <summary>
         /// Powershell Version to execute the background job.
@@ -574,12 +567,24 @@ namespace Microsoft.PowerShell.Commands
                     RemotingErrorIdStrings.IPCPwshExecutableNotFound,
                     PowerShellProcessInstance.PwshExePath);
 
-                var exception = new PSNotSupportedException(message);
                 var errorRecord = new ErrorRecord(
-                        exception,
-                        "IPCPwshExecutableNotFound",
-                        ErrorCategory.NotInstalled,
-                        PowerShellProcessInstance.PwshExePath);
+                    new PSNotSupportedException(message),
+                    "IPCPwshExecutableNotFound",
+                    ErrorCategory.NotInstalled,
+                    PowerShellProcessInstance.PwshExePath);
+
+                ThrowTerminatingError(errorRecord);
+            }
+
+            if (RunAs32.IsPresent && Environment.Is64BitProcess)
+            {
+                // We cannot start a 32-bit 'pwsh' process from a 64-bit 'pwsh' installation.
+                string message = RemotingErrorIdStrings.RunAs32NotSupported;
+                var errorRecord = new ErrorRecord(
+                    new PSNotSupportedException(message),
+                    "RunAs32NotSupported",
+                    ErrorCategory.InvalidOperation,
+                    targetObject: null);
 
                 ThrowTerminatingError(errorRecord);
             }
@@ -620,7 +625,6 @@ namespace Microsoft.PowerShell.Commands
             }
 
             NewProcessConnectionInfo connectionInfo = new NewProcessConnectionInfo(this.Credential);
-            connectionInfo.RunAs32 = _shouldRunAs32;
             connectionInfo.InitializationScript = _initScript;
             connectionInfo.AuthenticationMechanism = this.Authentication;
             connectionInfo.PSVersion = this.PSVersion;

src/System.Management.Automation/resources/RemotingErrorIdStrings.resx

@@ -791,8 +791,8 @@ Do you want to continue?</value>
     <value>The pwsh executable cannot be found at "{0}".
 Note that 'Start-Job' is not supported by design in scenarios where PowerShell is being hosted in other applications. Instead, usage of the 'ThreadJob' module is recommended in such scenarios.</value>
   </data>
-  <data name="IPCWowComponentNotPresent" xml:space="preserve">
-    <value>The "{0}" executable file was not found. Verify that the WOW64 feature is installed.</value>
+  <data name="RunAs32NotSupported" xml:space="preserve">
+    <value>Cannot start a 32-bit 'pwsh' process from the 64-bit 'pwsh' installation. Install the 32-bit 'pwsh' if you need to run PowerShell in a 32-bit process.</value>
   </data>
   <data name="IPCServerProcessReportedError" xml:space="preserve">
     <value>The background process reported an error with the following message: {0}.</value>

test/powershell/Modules/Microsoft.PowerShell.Core/Job.Tests.ps1

@@ -32,6 +32,13 @@ Describe "Job Cmdlet Tests" -Tag "CI" {
             Wait-Job -Timeout 60 -id $j.id | Should -Not -BeNullOrEmpty
             receive-job -id $j.id | Should -Be 2
         }
+        It "-RunAs32 not supported from 64-bit pwsh" -Skip:(-not [System.Environment]::Is64BitProcess) {
+            { Start-Job -ScriptBlock {} -RunAs32 } | Should -Throw -ErrorId "RunAs32NotSupported,Microsoft.PowerShell.Commands.StartJobCommand"
+        }
+        It "-RunAs32 supported in 32-bit pwsh" -Skip:([System.Environment]::Is64BitProcess) {
+            $job = Start-Job -ScriptBlock { 1+1 } -RunAs32
+            Receive-Job $job -Wait | Should -Be 2
+        }
     }
     Context "Jobs with arguments" {
         It "Start-Job accepts arguments" {

test/xUnit/csharp/test_PowerShellAPI.cs

@@ -7,10 +7,8 @@ using Xunit;
 
 namespace PSTests.Sequential
 {
-    // Not static because a test requires non-const variables
     public static class PowerShellHostingScenario
     {
-        // Test that it does not throw an exception
         [Fact]
         public static void TestStartJobThrowTerminatingException()
         {