Redirect stdout and stderr to named pipes

IPA.Injector/Injector.cs

@@ -48,6 +48,8 @@ namespace IPA.Injector
                 var arguments = Environment.GetCommandLineArgs();
                 MaybeInitializeConsole(arguments);
 
+                StdoutInterceptorPipes.Initialize();
+
                 SetupLibraryLoading();
 
                 EnsureDirectories();

IPA.Loader/Logging/StdoutInterceptor.cs

@@ -114,8 +114,8 @@ namespace IPA.Logging
             return "\x1b[" + code + "m";
         }
 
-        private static StdoutInterceptor? stdoutInterceptor;
-        private static StdoutInterceptor? stderrInterceptor;
+        internal static StdoutInterceptor? Stdout;
+        internal static StdoutInterceptor? Stderr;
 
         private static class ConsoleHarmonyPatches
         {
@@ -145,9 +145,9 @@ namespace IPA.Logging
                 }
             }
 
-            public static ConsoleColor GetColor() => stdoutInterceptor!.currentColor;
-            public static void SetColor(ConsoleColor col) => stdoutInterceptor!.currentColor = col;
-            public static void ResetColor() => stdoutInterceptor!.currentColor = defaultColor;
+            public static ConsoleColor GetColor() => Stdout!.currentColor;
+            public static void SetColor(ConsoleColor col) => Stdout!.currentColor = col;
+            public static void ResetColor() => Stdout!.currentColor = defaultColor;
 
             public static IEnumerable<CodeInstruction> PatchGetForegroundColor(IEnumerable<CodeInstruction> _)
             {
@@ -194,8 +194,8 @@ namespace IPA.Logging
 
                 HarmonyGlobalSettings.DisallowLegacyGlobalUnpatchAll = true;
                 harmony ??= new Harmony("BSIPA Console Redirector Patcher");
-                stdoutInterceptor ??= new StdoutInterceptor();
-                stderrInterceptor ??= new StdoutInterceptor { isStdErr = true };
+                Stdout ??= new StdoutInterceptor();
+                Stderr ??= new StdoutInterceptor { isStdErr = true };
 
                 RedirectConsole();
                 ConsoleHarmonyPatches.Patch(harmony);
@@ -206,8 +206,9 @@ namespace IPA.Logging
         {
             if (usingInterceptor)
             {
-                Console.SetOut(stdoutInterceptor);
-                Console.SetError(stderrInterceptor);
+                Console.SetOut(Stdout);
+                Console.SetError(Stderr);
+                StdoutInterceptorPipes.ShouldRedirectStdHandles = true;
             }
         }
 

IPA.Loader/Logging/StdoutInterceptorPipes.cs

@@ -0,0 +1,103 @@
+using System;
+using System.IO.Pipes;
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+using System.Text;
+using System.Threading;
+
+namespace IPA.Logging
+{
+    internal static class StdoutInterceptorPipes
+    {
+        // Used to ensure the server starts first, as Mono struggles with this simple task.
+        // Otherwise it would throw a ERROR_PIPE_CONNECTED Win32Exception.
+        private static readonly ManualResetEvent manualResetEvent = new(false);
+
+        public static bool ShouldRedirectStdHandles;
+
+        public static void Initialize()
+        {
+            InitializePipe(STD_OUTPUT_HANDLE);
+            InitializePipe(STD_ERROR_HANDLE);
+        }
+
+        private static void InitializePipe(int stdHandle)
+        {
+            var pipeName = stdHandle == STD_OUTPUT_HANDLE ? "STD_OUT_PIPE" : "STD_ERR_PIPE";
+            var serverThread = InstantiateServerThread(pipeName, stdHandle);
+            serverThread.Start();
+            var clientThread = InstantiateClientThread(pipeName, stdHandle);
+            clientThread.Start();
+        }
+
+        private static Thread InstantiateServerThread(string pipeName, int stdHandle)
+        {
+            return new Thread(() =>
+            {
+                NamedPipeServerStream pipeServer = new(pipeName, PipeDirection.In);
+
+                try
+                {
+                    // If the client starts first, releases the client thread.
+                    manualResetEvent.Set();
+                    pipeServer.WaitForConnection();
+                    var buffer = new byte[1024];
+                    while (pipeServer.IsConnected)
+                    {
+                        if (ShouldRedirectStdHandles)
+                        {
+                            // Separate method to avoid a BadImageFormatException when accessing StdoutInterceptor early.
+                            // This happens because the Harmony DLL is not loaded at this point.
+                            Redirect(pipeServer, buffer, stdHandle);
+                        }
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine(ex);
+                    pipeServer.Close();
+                }
+            });
+        }
+
+        private static Thread InstantiateClientThread(string pipeName, int stdHandle)
+        {
+            return new Thread(() =>
+            {
+                NamedPipeClientStream pipeClient = new(".", pipeName, PipeDirection.Out);
+
+                try
+                {
+                    // If the client starts first, blocks the client thread.
+                    manualResetEvent.WaitOne();
+                    pipeClient.Connect();
+                    SetStdHandle(stdHandle, pipeClient.SafePipeHandle.DangerousGetHandle());
+                    while (pipeClient.IsConnected)
+                    {
+                        // Keeps the thread alive.
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine(ex);
+                    pipeClient.Close();
+                }
+            });
+        }
+
+        private static void Redirect(NamedPipeServerStream server, byte[] buffer, int stdHandle)
+        {
+            var charsRead = server.Read(buffer, 0, buffer.Length);
+            var interceptor = stdHandle == STD_OUTPUT_HANDLE ? StdoutInterceptor.Stdout : StdoutInterceptor.Stderr;
+            interceptor!.Write(Encoding.UTF8.GetString(buffer, 0, charsRead));
+        }
+
+        [DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
+        [DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
+        [ResourceExposure(ResourceScope.Process)]
+        private static extern bool SetStdHandle(int nStdHandle, IntPtr hHandle);
+
+        private const int STD_OUTPUT_HANDLE = -11;
+        private const int STD_ERROR_HANDLE = -12;
+    }
+}