Allow opt-out of the named-pipe listener using the environment variable POWERSHELL_DIAGNOSTICS_OPTOUT (#26086)

src/System.Management.Automation/engine/Utils.cs

@@ -24,7 +24,6 @@ using System.Text;
 using System.Threading;
 using Microsoft.PowerShell.Commands;
 using Microsoft.Win32;
-using Microsoft.Win32.SafeHandles;
 
 using TypeTable = System.Management.Automation.Runspaces.TypeTable;
 
@@ -1548,6 +1547,72 @@ namespace System.Management.Automation
             }
             return true;
         }
+
+        /// <summary>
+        /// Determine whether the environment variable is set and how.
+        /// </summary>
+        /// <param name="name">The name of the environment variable.</param>
+        /// <param name="defaultValue">If the environment variable is not set, use this as the default value.</param>
+        /// <returns>A boolean representing the value of the environment variable.</returns>
+        internal static bool GetEnvironmentVariableAsBool(string name, bool defaultValue)
+        {
+            var str = Environment.GetEnvironmentVariable(name);
+            if (string.IsNullOrEmpty(str))
+            {
+                return defaultValue;
+            }
+
+            var boolStr = str.AsSpan();
+
+            if (boolStr.Length == 1)
+            {
+                if (boolStr[0] == '1')
+                {
+                    return true;
+                }
+
+                if (boolStr[0] == '0')
+                {
+                    return false;
+                }
+            }
+
+            if (boolStr.Length == 3 &&
+                (boolStr[0] == 'y' || boolStr[0] == 'Y') &&
+                (boolStr[1] == 'e' || boolStr[1] == 'E') &&
+                (boolStr[2] == 's' || boolStr[2] == 'S'))
+            {
+                return true;
+            }
+
+            if (boolStr.Length == 2 &&
+                (boolStr[0] == 'n' || boolStr[0] == 'N') &&
+                (boolStr[1] == 'o' || boolStr[1] == 'O'))
+            {
+                return false;
+            }
+
+            if (boolStr.Length == 4 &&
+                (boolStr[0] == 't' || boolStr[0] == 'T') &&
+                (boolStr[1] == 'r' || boolStr[1] == 'R') &&
+                (boolStr[2] == 'u' || boolStr[2] == 'U') &&
+                (boolStr[3] == 'e' || boolStr[3] == 'E'))
+            {
+                return true;
+            }
+
+            if (boolStr.Length == 5 &&
+                (boolStr[0] == 'f' || boolStr[0] == 'F') &&
+                (boolStr[1] == 'a' || boolStr[1] == 'A') &&
+                (boolStr[2] == 'l' || boolStr[2] == 'L') &&
+                (boolStr[3] == 's' || boolStr[3] == 'S') &&
+                (boolStr[4] == 'e' || boolStr[4] == 'E'))
+            {
+                return false;
+            }
+
+            return defaultValue;
+        }
     }
 }
 

src/System.Management.Automation/engine/remoting/common/RemoteSessionNamedPipe.cs

@@ -12,7 +12,6 @@ using System.Runtime.InteropServices;
 using System.Security.AccessControl;
 using System.Security.Principal;
 using System.Threading;
-using System.Threading.Tasks;
 
 using Microsoft.Win32.SafeHandles;
 
@@ -500,13 +499,14 @@ namespace System.Management.Automation.Remoting
         {
             s_syncObject = new object();
 
-            // All PowerShell instances will start with the named pipe
-            // and listener created and running.
-            IPCNamedPipeServerEnabled = true;
+            // Unless opt-out, all PowerShell instances will start with the named-pipe listener created and running.
+            IPCNamedPipeServerEnabled = !Utils.GetEnvironmentVariableAsBool(name: "POWERSHELL_DIAGNOSTICS_OPTOUT", defaultValue: false);
 
-            CreateIPCNamedPipeServerSingleton();
-
-            CreateProcessExitHandler();
+            if (IPCNamedPipeServerEnabled)
+            {
+                CreateIPCNamedPipeServerSingleton();
+                CreateProcessExitHandler();
+            }
         }
 
         #endregion

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

@@ -1411,7 +1411,7 @@ All WinRM sessions connected to PowerShell session configurations, such as Micro
     <value>Multiple processes were found with this name {0}. Use the process Id to specify a single process to enter.</value>
   </data>
   <data name="EnterPSHostProcessNoPowerShell" xml:space="preserve">
-    <value>Cannot enter process with Id '{0}' because it has not loaded the PowerShell engine.</value>
+    <value>Cannot enter process with Id '{0}' because it has not loaded the PowerShell engine or the named-pipe listener was disabled.</value>
   </data>
   <data name="EnterPSHostProcessNoProcessFoundWithId" xml:space="preserve">
     <value>No process was found with Id: {0}.</value>

src/System.Management.Automation/utils/Telemetry.cs

@@ -8,7 +8,6 @@ using System.IO;
 using System.Linq;
 using System.Management.Automation;
 using System.Runtime.InteropServices;
-using System.Security.AccessControl;
 using System.Threading;
 
 using Microsoft.ApplicationInsights;
@@ -177,7 +176,7 @@ namespace Microsoft.PowerShell.Telemetry
         static ApplicationInsightsTelemetry()
         {
             // If we can't send telemetry, there's no reason to do any of this
-            CanSendTelemetry = !GetEnvironmentVariableAsBool(name: _telemetryOptoutEnvVar, defaultValue: false);
+            CanSendTelemetry = !Utils.GetEnvironmentVariableAsBool(name: _telemetryOptoutEnvVar, defaultValue: false);
             if (CanSendTelemetry)
             {
                 s_sessionId = Guid.NewGuid().ToString();
@@ -643,72 +642,6 @@ namespace Microsoft.PowerShell.Telemetry
             }
         }
 
-        /// <summary>
-        /// Determine whether the environment variable is set and how.
-        /// </summary>
-        /// <param name="name">The name of the environment variable.</param>
-        /// <param name="defaultValue">If the environment variable is not set, use this as the default value.</param>
-        /// <returns>A boolean representing the value of the environment variable.</returns>
-        private static bool GetEnvironmentVariableAsBool(string name, bool defaultValue)
-        {
-            var str = Environment.GetEnvironmentVariable(name);
-            if (string.IsNullOrEmpty(str))
-            {
-                return defaultValue;
-            }
-
-            var boolStr = str.AsSpan();
-
-            if (boolStr.Length == 1)
-            {
-                if (boolStr[0] == '1')
-                {
-                    return true;
-                }
-
-                if (boolStr[0] == '0')
-                {
-                    return false;
-                }
-            }
-
-            if (boolStr.Length == 3 &&
-                (boolStr[0] == 'y' || boolStr[0] == 'Y') &&
-                (boolStr[1] == 'e' || boolStr[1] == 'E') &&
-                (boolStr[2] == 's' || boolStr[2] == 'S'))
-            {
-                return true;
-            }
-
-            if (boolStr.Length == 2 &&
-                (boolStr[0] == 'n' || boolStr[0] == 'N') &&
-                (boolStr[1] == 'o' || boolStr[1] == 'O'))
-            {
-                return false;
-            }
-
-            if (boolStr.Length == 4 &&
-                (boolStr[0] == 't' || boolStr[0] == 'T') &&
-                (boolStr[1] == 'r' || boolStr[1] == 'R') &&
-                (boolStr[2] == 'u' || boolStr[2] == 'U') &&
-                (boolStr[3] == 'e' || boolStr[3] == 'E'))
-            {
-                return true;
-            }
-
-            if (boolStr.Length == 5 &&
-                (boolStr[0] == 'f' || boolStr[0] == 'F') &&
-                (boolStr[1] == 'a' || boolStr[1] == 'A') &&
-                (boolStr[2] == 'l' || boolStr[2] == 'L') &&
-                (boolStr[3] == 's' || boolStr[3] == 'S') &&
-                (boolStr[4] == 'e' || boolStr[4] == 'E'))
-            {
-                return false;
-            }
-
-            return defaultValue;
-        }
-
         /// <summary>
         /// Send module load telemetry as a metric.
         /// For modules we send the module name (if allowed), and the version.