[MWB] Fix file transfer not working in service mode (#37542)

* [MWB] Fix file transfer not working in service mode

* Spellcheck issues

src/modules/MouseWithoutBorders/App/Class/Common.Helper.cs

@@ -9,6 +9,7 @@ using System.Drawing;
 using System.Globalization;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Security.Principal;
 using System.Windows.Forms;
 
@@ -443,7 +444,31 @@ namespace MouseWithoutBorders
                 {
                     _ = Common.ImpersonateLoggedOnUserAndDoSomething(() =>
                     {
-                        Setting.Values.Username = WindowsIdentity.GetCurrent(true).Name;
+                        // See: https://stackoverflow.com/questions/19487541/how-to-get-windows-user-name-from-sessionid
+                        static string GetUsernameBySessionId(int sessionId)
+                        {
+                            string username = "SYSTEM";
+                            if (NativeMethods.WTSQuerySessionInformation(IntPtr.Zero, sessionId, NativeMethods.WTSInfoClass.WTSUserName, out nint buffer, out int strLen) && strLen > 1)
+                            {
+                                username = Marshal.PtrToStringAnsi(buffer);
+                                NativeMethods.WTSFreeMemory(buffer);
+
+                                if (NativeMethods.WTSQuerySessionInformation(IntPtr.Zero, sessionId, NativeMethods.WTSInfoClass.WTSDomainName, out buffer, out strLen) && strLen > 1)
+                                {
+                                    username = @$"{Marshal.PtrToStringAnsi(buffer)}\{username}";
+                                    NativeMethods.WTSFreeMemory(buffer);
+                                }
+                            }
+
+                            return username;
+                        }
+
+                        // The most direct way to fetch the username is WindowsIdentity.GetCurrent(true).Name
+                        // but GetUserName can run within an ExecutionContext.SuppressFlow block, which creates issues
+                        // with WindowsIdentity.GetCurrent.
+                        // See: https://stackoverflow.com/questions/76998988/exception-when-using-executioncontext-suppressflow-in-net-7
+                        // So we use WTSQuerySessionInformation as a workaround.
+                        Setting.Values.Username = GetUsernameBySessionId(Process.GetCurrentProcess().SessionId);
                     });
                 }
                 else

src/modules/MouseWithoutBorders/App/Class/Common.Launch.cs

@@ -5,7 +5,6 @@
 using System;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Runtime.InteropServices;
 using System.Security.Principal;
@@ -39,23 +38,31 @@ namespace MouseWithoutBorders
             }
             else
             {
+                // SuppressFlow fixes an issue on service mode, where WTSQueryUserToken runs successfully once and then fails
+                // on subsequent calls. The reason appears to be an unknown issue with reverting the impersonation,
+                // meaning that subsequent impersonation attempts run as the logged-on user and fail.
+                // This is a workaround.
+                using var asyncFlowControl = System.Threading.ExecutionContext.SuppressFlow();
+
                 uint dwSessionId;
                 IntPtr hUserToken = IntPtr.Zero, hUserTokenDup = IntPtr.Zero;
                 try
                 {
                     dwSessionId = (uint)Process.GetCurrentProcess().SessionId;
                     uint rv = NativeMethods.WTSQueryUserToken(dwSessionId, ref hUserToken);
-                    Logger.LogDebug("WTSQueryUserToken returned " + rv.ToString(CultureInfo.CurrentCulture));
+                    var lastError = rv == 0 ? Marshal.GetLastWin32Error() : 0;
+
+                    Logger.LogDebug($"{nameof(NativeMethods.WTSQueryUserToken)} returned {rv.ToString(CultureInfo.CurrentCulture)}");
 
                     if (rv == 0)
                     {
-                        Logger.LogDebug($"WTSQueryUserToken failed with: {Marshal.GetLastWin32Error()}.");
+                        Logger.Log($"{nameof(NativeMethods.WTSQueryUserToken)} failed with: {lastError}.");
                         return false;
                     }
 
                     if (!NativeMethods.DuplicateToken(hUserToken, (int)NativeMethods.SECURITY_IMPERSONATION_LEVEL.SecurityImpersonation, ref hUserTokenDup))
                     {
-                        Logger.TelemetryLogTrace($"DuplicateToken Failed! {Logger.GetStackTrace(new StackTrace())}", SeverityLevel.Warning);
+                        Logger.TelemetryLogTrace($"{nameof(NativeMethods.DuplicateToken)} Failed! {Logger.GetStackTrace(new StackTrace())}", SeverityLevel.Warning);
                         _ = NativeMethods.CloseHandle(hUserToken);
                         _ = NativeMethods.CloseHandle(hUserTokenDup);
                         return false;

src/modules/MouseWithoutBorders/App/Class/NativeMethods.cs

@@ -75,6 +75,41 @@ namespace MouseWithoutBorders.Class
         [DllImport("kernel32.dll")]
         internal static extern uint WTSGetActiveConsoleSessionId();
 
+        [DllImport("Wtsapi32.dll")]
+        internal static extern bool WTSQuerySessionInformation(IntPtr hServer, int sessionId, WTSInfoClass infoClass, out IntPtr ppBuffer, out int pBytesReturned);
+
+        [DllImport("Wtsapi32.dll")]
+        internal static extern void WTSFreeMemory(IntPtr pointer);
+
+        internal enum WTSInfoClass
+        {
+            WTSInitialProgram,
+            WTSApplicationName,
+            WTSWorkingDirectory,
+            WTSOEMId,
+            WTSSessionId,
+            WTSUserName,
+            WTSWinStationName,
+            WTSDomainName,
+            WTSConnectState,
+            WTSClientBuildNumber,
+            WTSClientName,
+            WTSClientDirectory,
+            WTSClientProductId,
+            WTSClientHardwareId,
+            WTSClientAddress,
+            WTSClientDisplay,
+            WTSClientProtocolType,
+            WTSIdleTime,
+            WTSLogonTime,
+            WTSIncomingBytes,
+            WTSOutgoingBytes,
+            WTSIncomingFrames,
+            WTSOutgoingFrames,
+            WTSClientInfo,
+            WTSSessionInfo,
+        }
+
 #endif
 
         [DllImport("user32.dll", SetLastError = true)]
@@ -812,7 +847,7 @@ namespace MouseWithoutBorders.Class
 
         // [DllImport("kernel32.dll", SetLastError = true)]
         // internal static extern IntPtr CreateToolhelp32Snapshot(UInt32 dwFlags, UInt32 th32ProcessID);
-        [DllImport("Wtsapi32.dll")]
+        [DllImport("Wtsapi32.dll", SetLastError = true)]
         internal static extern uint WTSQueryUserToken(uint SessionId, ref IntPtr phToken);
 
         [SuppressMessage("Microsoft.Globalization", "CA2101:SpecifyMarshalingForPInvokeStringArguments", MessageId = "1", Justification = "Dotnet port with style preservation")]