feat(init): from claude

csharp/TimeMocker.Hook/InjectionEntryPoint.cs

@@ -0,0 +1,190 @@
+using System;
+using System.IO;
+using System.IO.Pipes;
+using System.Runtime.InteropServices;
+using System.Threading;
+using EasyHook;
+
+namespace TimeMocker.Hook
+{
+    /// <summary>
+    /// Shared memory layout written by the UI and read by the hook.
+    /// Stored in a named memory-mapped file so no pipe latency on hot path.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    public struct MockTimeInfo
+    {
+        public long FakeUtcTicks;   // DateTime ticks (UTC)
+        public int  Enabled;        // 1 = mock active, 0 = passthrough
+    }
+
+    // -------------------------------------------------------------------------
+    // Win32 structs
+    // -------------------------------------------------------------------------
+    [StructLayout(LayoutKind.Sequential)]
+    public struct SYSTEMTIME
+    {
+        public ushort wYear, wMonth, wDayOfWeek, wDay;
+        public ushort wHour, wMinute, wSecond, wMilliseconds;
+
+        public static SYSTEMTIME FromDateTime(DateTime dt)
+        {
+            return new SYSTEMTIME
+            {
+                wYear         = (ushort)dt.Year,
+                wMonth        = (ushort)dt.Month,
+                wDayOfWeek    = (ushort)dt.DayOfWeek,
+                wDay          = (ushort)dt.Day,
+                wHour         = (ushort)dt.Hour,
+                wMinute       = (ushort)dt.Minute,
+                wSecond       = (ushort)dt.Second,
+                wMilliseconds = (ushort)dt.Millisecond
+            };
+        }
+    }
+
+    // -------------------------------------------------------------------------
+    // EasyHook entry point – called after DLL is injected
+    // -------------------------------------------------------------------------
+    public class InjectionEntryPoint : IEntryPoint
+    {
+        private readonly string _mmfName;
+        private System.IO.MemoryMappedFiles.MemoryMappedFile _mmf;
+        private System.IO.MemoryMappedFiles.MemoryMappedViewAccessor _view;
+
+        // Hook handles
+        private LocalHook _getSystemTimeHook;
+        private LocalHook _getLocalTimeHook;
+        private LocalHook _ntQuerySystemTimeHook;
+        private LocalHook _getSystemTimeAsFileTimeHook;
+        private LocalHook _getSystemTimePreciseAsFileTimeHook;
+
+        public InjectionEntryPoint(RemoteHooking.IContext context, string mmfName)
+        {
+            _mmfName = mmfName;
+        }
+
+        public void Run(RemoteHooking.IContext context, string mmfName)
+        {
+            try
+            {
+                // Open the shared memory created by the UI process
+                _mmf  = System.IO.MemoryMappedFiles.MemoryMappedFile.OpenExisting(mmfName);
+                _view = _mmf.CreateViewAccessor(0, Marshal.SizeOf<MockTimeInfo>());
+
+                InstallHooks();
+                RemoteHooking.WakeUpProcess();
+
+                // Keep alive until process exits
+                while (true) Thread.Sleep(500);
+            }
+            catch (Exception ex)
+            {
+                File.AppendAllText(
+                    Path.Combine(Path.GetTempPath(), "TimeMocker.Hook.log"),
+                    $"[{DateTime.Now}] ERROR: {ex}\r\n");
+            }
+            finally
+            {
+                _getSystemTimeHook?.Dispose();
+                _getLocalTimeHook?.Dispose();
+                _ntQuerySystemTimeHook?.Dispose();
+                _getSystemTimeAsFileTimeHook?.Dispose();
+                _getSystemTimePreciseAsFileTimeHook?.Dispose();
+                _view?.Dispose();
+                _mmf?.Dispose();
+            }
+        }
+
+        // -------------------------------------------------------------------------
+        // Helpers
+        // -------------------------------------------------------------------------
+        private MockTimeInfo ReadMockInfo()
+        {
+            _view.Read(0, out MockTimeInfo info);
+            return info;
+        }
+
+        private DateTime GetFakeUtc()
+        {
+            var info = ReadMockInfo();
+            return info.Enabled == 1
+                ? new DateTime(info.FakeUtcTicks, DateTimeKind.Utc)
+                : DateTime.UtcNow;
+        }
+
+        private void InstallHooks()
+        {
+            _getSystemTimeHook = LocalHook.Create(
+                LocalHook.GetProcAddress("kernel32.dll", "GetSystemTime"),
+                new GetSystemTimeDelegate(GetSystemTime_Hook), this);
+            _getSystemTimeHook.ThreadACL.SetExclusiveACL(new[] { 0 });
+
+            _getLocalTimeHook = LocalHook.Create(
+                LocalHook.GetProcAddress("kernel32.dll", "GetLocalTime"),
+                new GetLocalTimeDelegate(GetLocalTime_Hook), this);
+            _getLocalTimeHook.ThreadACL.SetExclusiveACL(new[] { 0 });
+
+            _ntQuerySystemTimeHook = LocalHook.Create(
+                LocalHook.GetProcAddress("ntdll.dll", "NtQuerySystemTime"),
+                new NtQuerySystemTimeDelegate(NtQuerySystemTime_Hook), this);
+            _ntQuerySystemTimeHook.ThreadACL.SetExclusiveACL(new[] { 0 });
+
+            _getSystemTimeAsFileTimeHook = LocalHook.Create(
+                LocalHook.GetProcAddress("kernel32.dll", "GetSystemTimeAsFileTime"),
+                new GetSystemTimeAsFileTimeDelegate(GetSystemTimeAsFileTime_Hook), this);
+            _getSystemTimeAsFileTimeHook.ThreadACL.SetExclusiveACL(new[] { 0 });
+
+            _getSystemTimePreciseAsFileTimeHook = LocalHook.Create(
+                LocalHook.GetProcAddress("kernel32.dll", "GetSystemTimePreciseAsFileTime"),
+                new GetSystemTimeAsFileTimeDelegate(GetSystemTimePreciseAsFileTime_Hook), this);
+            _getSystemTimePreciseAsFileTimeHook.ThreadACL.SetExclusiveACL(new[] { 0 });
+        }
+
+        // -------------------------------------------------------------------------
+        // Hook implementations
+        // -------------------------------------------------------------------------
+
+        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
+        delegate void GetSystemTimeDelegate(out SYSTEMTIME lpSystemTime);
+
+        void GetSystemTime_Hook(out SYSTEMTIME lpSystemTime)
+        {
+            lpSystemTime = SYSTEMTIME.FromDateTime(GetFakeUtc());
+        }
+
+        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
+        delegate void GetLocalTimeDelegate(out SYSTEMTIME lpLocalTime);
+
+        void GetLocalTime_Hook(out SYSTEMTIME lpLocalTime)
+        {
+            lpLocalTime = SYSTEMTIME.FromDateTime(GetFakeUtc().ToLocalTime());
+        }
+
+        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
+        delegate int NtQuerySystemTimeDelegate(out long systemTime);
+
+        int NtQuerySystemTime_Hook(out long systemTime)
+        {
+            // FILETIME epoch: Jan 1, 1601
+            var epoch = new DateTime(1601, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            systemTime = (GetFakeUtc() - epoch).Ticks;
+            return 0; // STATUS_SUCCESS
+        }
+
+        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
+        delegate void GetSystemTimeAsFileTimeDelegate(out long lpFileTime);
+
+        void GetSystemTimeAsFileTime_Hook(out long lpFileTime)
+        {
+            var epoch = new DateTime(1601, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            lpFileTime = (GetFakeUtc() - epoch).Ticks;
+        }
+
+        void GetSystemTimePreciseAsFileTime_Hook(out long lpFileTime)
+        {
+            var epoch = new DateTime(1601, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+            lpFileTime = (GetFakeUtc() - epoch).Ticks;
+        }
+    }
+}