PowerShell · daxian-dbw · Apr 28, 2021 · Jan 22, 2021 · Jan 22, 2021 · Jan 25, 2021
diff --git a/src/System.Management.Automation/CoreCLR/CorePsAssemblyLoadContext.cs b/src/System.Management.Automation/CoreCLR/CorePsAssemblyLoadContext.cs
@@ -587,4 +587,35 @@ public static void SetPowerShellAssemblyLoadContext([MarshalAs(UnmanagedType.LPW
             PowerShellAssemblyLoadContext.InitializeSingleton(basePaths);
         }
     }
+
+    /// <summary>
+    /// Provides helper functions to faciliate calling managed code from a native PowerShell host.
+    /// </summary>
+    public static unsafe class PowerShellUnsafeAssemblyLoad
+    {
+        /// <summary>
+        /// Load an assembly in memory from unmanaged code.
+        /// </summary>
+        /// <remarks>
+        /// This API is covered by the experimental feature 'PSLoadAssemblyFromNativeCode',
+        /// and it may be deprecated and removed in future.
+        /// </remarks>
+        /// <param name="data">Unmanaged pointer to assembly data buffer.</param>
+        /// <param name="size">Size in bytes of the assembly data buffer.</param>
+        /// <returns>Returns zero on success and non-zero on failure.</returns>
+        [UnmanagedCallersOnly]
+        public static int LoadAssemblyFromNativeMemory(IntPtr data, int size)
+        {
+            try
+            {
+                using var stream = new UnmanagedMemoryStream((byte*)data, size);
+                AssemblyLoadContext.Default.LoadFromStream(stream);
+                return 0;
+            }
+            catch
+            {
+                return -1;
+            }
+        }
+    }
 }
diff --git a/src/System.Management.Automation/engine/ExperimentalFeature/ExperimentalFeature.cs b/src/System.Management.Automation/engine/ExperimentalFeature/ExperimentalFeature.cs
@@ -140,7 +140,11 @@ static ExperimentalFeature()
                 new ExperimentalFeature(
                     name: PSNativeCommandArgumentPassingFeatureName,
                     description: "Use ArgumentList when invoking a native command"),
+                new ExperimentalFeature(
+                    name: "PSLoadAssemblyFromNativeCode",
+                    description: "Expose an API to allow assembly loading from native code"),
             };
+
             EngineExperimentalFeatures = new ReadOnlyCollection<ExperimentalFeature>(engineFeatures);
 
             // Initialize the readonly dictionary 'EngineExperimentalFeatureMap'.

diff --git a/test/xUnit/csharp/test_NativeInterop.cs b/test/xUnit/csharp/test_NativeInterop.cs
@@ -0,0 +1,107 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using System.Runtime.Loader;
+using System.Management.Automation;
+using Xunit;
+
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.Emit;
+using Microsoft.CodeAnalysis.Text;
+
+namespace PSTests.Sequential
+{
+    public static class NativeInterop
+    {
+        [Fact]
+        public static void TestLoadNativeInMemoryAssembly()
+        {
+            string tempDir = Path.Combine(Path.GetTempPath(), "TestLoadNativeInMemoryAssembly");
+            string testDll = Path.Combine(tempDir, "test.dll");
+
+            if (!File.Exists(testDll))
+            {
+                Directory.CreateDirectory(tempDir);
+                bool result = CreateTestDll(testDll);
+                Assert.True(result, "The call to 'CreateTestDll' should be successful and return true.");
+                Assert.True(File.Exists(testDll), "The test assembly should be created.");
+            }
+
+            var asmName = AssemblyName.GetAssemblyName(testDll);
+            string asmFullName = SearchAssembly(asmName.Name);
+            Assert.Null(asmFullName);
+
+            unsafe
+            {
+                int ret = LoadAssemblyTest(testDll);
+                Assert.Equal(0, ret);
+            }
+
+            asmFullName = SearchAssembly(asmName.Name);
+            Assert.Equal(asmName.FullName, asmFullName);
+        }
+
+        private static unsafe int LoadAssemblyTest(string assemblyPath)
+        {
+            // The 'LoadAssemblyFromNativeMemory' method is annotated with 'UnmanagedCallersOnly' attribute,
+            // so we have to use the 'unmanaged' function pointer to invoke it.
+            delegate* unmanaged<IntPtr, int, int> funcPtr = &PowerShellUnsafeAssemblyLoad.LoadAssemblyFromNativeMemory;
+
+            int length = 0;
+            IntPtr nativeMem = IntPtr.Zero;
+
+            try
+            {
+                using (var fileStream = new FileStream(assemblyPath, FileMode.Open, FileAccess.Read))
+                {
+                    length = (int)fileStream.Length;
+                    nativeMem = Marshal.AllocHGlobal(length);
+
+                    using var unmanagedStream = new UnmanagedMemoryStream((byte*)nativeMem, length, length, FileAccess.Write);
+                    fileStream.CopyTo(unmanagedStream);
+                }
+
+                // Call the function pointer.
+                return funcPtr(nativeMem, length);
+            }
+            finally
+            {
+                // Free the native memory
+                Marshal.FreeHGlobal(nativeMem);
+            }
+        }
+
+        private static string SearchAssembly(string assemblyName)
+        {
+            Assembly asm = AssemblyLoadContext.Default.Assemblies.FirstOrDefault(
+                assembly => assembly.FullName.StartsWith(assemblyName, StringComparison.OrdinalIgnoreCase));
+
+            return asm?.FullName;
+        }
+
+        private static bool CreateTestDll(string dllPath)
+        {
+            var parseOptions = CSharpParseOptions.Default.WithLanguageVersion(LanguageVersion.Latest);
+            var compilationOptions = new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary);
+
+            List<SyntaxTree> syntaxTrees = new();
+            SourceText sourceText = SourceText.From("public class Utt { }");
+            syntaxTrees.Add(CSharpSyntaxTree.ParseText(sourceText, parseOptions));
+
+            var refs = new List<PortableExecutableReference> { MetadataReference.CreateFromFile(typeof(object).Assembly.Location) };
+            Compilation compilation = CSharpCompilation.Create(
+                        Path.GetRandomFileName(),
+                        syntaxTrees: syntaxTrees,
+                        references: refs,
+                        options: compilationOptions);
+
+            using var fs = new FileStream(dllPath, FileMode.CreateNew, FileAccess.ReadWrite, FileShare.None);
+            EmitResult emitResult = compilation.Emit(peStream: fs, options: null);
+            return emitResult.Success;
+        }
+    }
+}