Add separate handler for process modules (#1947)

Dalamud/Support/CurrentProcessModules.cs

@@ -0,0 +1,138 @@
+using System.Collections.Concurrent;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Serilog;
+
+using TerraFX.Interop.Windows;
+
+namespace Dalamud.Support;
+
+/// <summary>Tracks the loaded process modules.</summary>
+[ServiceManager.EarlyLoadedService]
+internal sealed unsafe partial class CurrentProcessModules : IInternalDisposableService
+{
+    private static readonly ConcurrentQueue<string> LogQueue = new();
+    private static readonly SemaphoreSlim LogSemaphore = new(0);
+
+    private static Process? process;
+    private static nint cookie;
+
+    private readonly CancellationTokenSource logTaskStop = new();
+    private readonly Task logTask;
+
+    [ServiceManager.ServiceConstructor]
+    private CurrentProcessModules()
+    {
+        var res = LdrRegisterDllNotification(0, &DllNotificationCallback, 0, out cookie);
+        if (res != STATUS.STATUS_SUCCESS)
+        {
+            Log.Error("{what}: LdrRegisterDllNotification failure: 0x{err}", nameof(CurrentProcessModules), res);
+            cookie = 0;
+            this.logTask = Task.CompletedTask;
+            return;
+        }
+
+        this.logTask = Task.Factory.StartNew(
+            () =>
+            {
+                while (!this.logTaskStop.IsCancellationRequested)
+                {
+                    LogSemaphore.Wait();
+                    while (LogQueue.TryDequeue(out var log))
+                        Log.Verbose(log);
+                }
+            },
+            this.logTaskStop.Token,
+            TaskCreationOptions.LongRunning,
+            TaskScheduler.Default);
+    }
+
+    private enum LdrDllNotificationReason : uint
+    {
+        Loaded = 1,
+        Unloaded = 2,
+    }
+
+    /// <summary>Gets all the loaded modules, up to date.</summary>
+    public static ProcessModuleCollection ModuleCollection =>
+        (cookie == 0 ? Process.GetCurrentProcess() : process ??= Process.GetCurrentProcess()).Modules;
+
+    /// <inheritdoc/>
+    void IInternalDisposableService.DisposeService()
+    {
+        if (Interlocked.Exchange(ref cookie, 0) is var copy and not 0)
+            LdrUnregisterDllNotification(copy);
+        if (!this.logTask.IsCompleted)
+        {
+            this.logTaskStop.Cancel();
+            LogSemaphore.Release();
+            this.logTask.Wait();
+        }
+    }
+
+    [UnmanagedCallersOnly]
+    private static void DllNotificationCallback(
+        LdrDllNotificationReason reason,
+        LdrDllNotificationData* data,
+        nint context)
+    {
+        process = null;
+        var name = new ReadOnlySpan<char>(data->FullDllName->Buffer, data->FullDllName->Length / 2);
+        LogQueue.Enqueue(
+            $"[{nameof(CurrentProcessModules)}]: {reason}: {name} @ 0x{data->DllBase:X} ({data->SizeOfImage}:X bytes)");
+        LogSemaphore.Release();
+    }
+
+    /// <summary>
+    /// Registers for notification when a DLL is first loaded.
+    /// This notification occurs before dynamic linking takes place.<br /><br />
+    /// <a href="https://learn.microsoft.com/en-us/windows/win32/devnotes/ldrregisterdllnotification">Docs.</a>
+    /// </summary>
+    /// <param name="flags">This parameter must be zero.</param>
+    /// <param name="notificationFunction">A pointer to a callback function to call when the DLL is loaded.</param>
+    /// <param name="context">A pointer to context data for the callback function.</param>
+    /// <param name="cookie">A pointer to a variable to receive an identifier for the callback function.
+    /// This identifier is used to unregister the notification callback function.</param>
+    /// <returns>Returns an NTSTATUS or error code.</returns>
+    [LibraryImport("ntdll.dll", SetLastError = true)]
+    private static partial int LdrRegisterDllNotification(
+        uint flags,
+        delegate* unmanaged<LdrDllNotificationReason, LdrDllNotificationData*, nint, void>
+            notificationFunction,
+        nint context,
+        out nint cookie);
+
+    /// <summary>
+    /// Cancels DLL load notification previously registered by calling the LdrRegisterDllNotification function.<br />
+    /// <br />
+    /// <a href="https://learn.microsoft.com/en-us/windows/win32/devnotes/ldrunregisterdllnotification">Docs.</a>
+    /// </summary>
+    /// <param name="cookie">A pointer to the callback identifier received from the LdrRegisterDllNotification call
+    /// that registered for notification.
+    /// </param>
+    /// <returns>Returns an NTSTATUS or error code.</returns>
+    [LibraryImport("ntdll.dll", SetLastError = true)]
+    private static partial int LdrUnregisterDllNotification(nint cookie);
+
+    [StructLayout(LayoutKind.Sequential)]
+    private struct LdrDllNotificationData
+    {
+        /// <summary>Reserved.</summary>
+        public uint Flags;
+
+        /// <summary>The full path name of the DLL module.</summary>
+        public UNICODE_STRING* FullDllName;
+
+        /// <summary>The base file name of the DLL module.</summary>
+        public UNICODE_STRING* BaseDllName;
+
+        /// <summary>A pointer to the base address for the DLL in memory.</summary>
+        public nint DllBase;
+
+        /// <summary>The size of the DLL image, in bytes.</summary>
+        public uint SizeOfImage;
+    }
+}

Dalamud/Utility/Util.cs

@@ -27,6 +27,8 @@ using Windows.Win32.Storage.FileSystem;
 using Windows.Win32.System.Memory;
 using Windows.Win32.System.Ole;
 
+using Dalamud.Support;
+
 using static TerraFX.Interop.Windows.Windows;
 
 using Win32_PInvoke = Windows.Win32.PInvoke;
@@ -191,7 +193,7 @@ public static class Util
     public static unsafe string DescribeAddress(nint p)
     {
         Span<char> namebuf = stackalloc char[9];
-        var modules = Process.GetCurrentProcess().Modules;
+        var modules = CurrentProcessModules.ModuleCollection;
         for (var i = 0; i < modules.Count; i++)
         {
             if (p < modules[i].BaseAddress) continue;