[NativeAOT] set environment variables before the app .so is loaded

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.NativeAOT.targets

@@ -123,7 +123,7 @@ This file contains the NativeAOT-specific MSBuild logic for .NET for Android.
       <!-- Include libc++ -->
       <_NdkLibs Include="$(_NdkSysrootDir)libc++_static.a" />
       <_NdkLibs Include="$(_NdkSysrootDir)libc++abi.a" />
-      
+
       <LinkerArg Include="&quot;%(_NdkLibs.Identity)&quot;" />
 
       <!-- This library conflicts with static libc++ -->
@@ -181,7 +181,6 @@ This file contains the NativeAOT-specific MSBuild logic for .NET for Android.
         OutputSources="@(_PrivateJniInitFuncsAssemblySource)" />
 
     <GenerateNativeAotEnvironmentAssemblerSources
-        Debug="$(AndroidIncludeDebugSymbols)"
         Environments="@(AndroidEnvironment);@(LibraryEnvironments)"
         HttpClientHandlerType="$(AndroidHttpClientHandlerType)"
         OutputSources="@(_PrivateEnvironmentAssemblySource)"

src/Xamarin.Android.Build.Tasks/Resources/NativeAotEnvironmentVars.java

@@ -0,0 +1,38 @@
+package net.dot.jni.nativeaot;
+
+import android.system.ErrnoException;
+import android.system.Os;
+import android.util.Log;
+import java.lang.String;
+
+public class NativeAotEnvironmentVars
+{
+	private static final String TAG = "NativeAotEnvironmentVars";
+
+	static String[] envNames = new String[] {
+@ENVIRONMENT_VAR_NAMES@
+	};
+
+	static String[] envValues = new String[] {
+@ENVIRONMENT_VAR_VALUES@
+	};
+
+	public static void Initialize ()
+	{
+		Log.d (TAG, "Initializing environment variables");
+
+		if (envNames.length != envValues.length) {
+			Log.w (TAG, "Unable to initialize environment variables, name and value arrays have different sizes");
+			return;
+		}
+
+		try {
+			for (int i = 0; i < envNames.length; i++) {
+				Log.d (TAG, "Setting env var: '" + envNames[i] + "'='" + envValues[i] + "'");
+				Os.setenv (envNames[i], envValues[i], true /* overwrite */);
+			}
+		} catch (ErrnoException e) {
+			Log.e (TAG, "Failed to set environment variables");
+		}
+	}
+}

src/Xamarin.Android.Build.Tasks/Resources/NativeAotRuntimeProvider.java

@@ -13,6 +13,7 @@ public class NativeAotRuntimeProvider
 
     public NativeAotRuntimeProvider() {
         Log.d(TAG, "NativeAotRuntimeProvider()");
+        NativeAotEnvironmentVars.Initialize ();
     }
 
     @Override

src/Xamarin.Android.Build.Tasks/Tasks/GenerateAdditionalProviderSources.cs

@@ -1,7 +1,9 @@
 #nullable enable
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using Java.Interop.Tools.JavaCallableWrappers;
 using Microsoft.Android.Build.Tasks;
 using Microsoft.Build.Framework;
@@ -28,6 +30,13 @@ public class GenerateAdditionalProviderSources : AndroidTask
 	[Required]
 	public string TargetName { get; set; } = "";
 
+	public ITaskItem[]? Environments { get; set; }
+
+	// We need to pass these two to the environment builder, otherwise not used
+	// by this task. See also GenerateNativeApplicationSources.cs
+	public string? HttpClientHandlerType { get; set; }
+	public bool EnableSGenConcurrent { get; set; }
+
 	AndroidRuntime androidRuntime;
 	JavaPeerStyle codeGenerationTarget;
 
@@ -71,14 +80,37 @@ void Generate (NativeCodeGenStateObject codeGenState)
 			Files.CopyIfStringChanged (contents, real_provider);
 		}
 
-		// For NativeAOT, generate JavaInteropRuntime.java
+		// For NativeAOT, generate JavaInteropRuntime.java and NativeAotEnvironmentVars.java
 		if (androidRuntime == Xamarin.Android.Tasks.AndroidRuntime.NativeAOT) {
-			const string fileName = "JavaInteropRuntime.java";
-			string template = GetResource (fileName);
-			var contents = template.Replace ("@MAIN_ASSEMBLY_NAME@", TargetName);
-			var path = Path.Combine (OutputDirectory, "src", "net", "dot", "jni", "nativeaot", fileName);
-			Log.LogDebugMessage ($"Writing: {path}");
-			Files.CopyIfStringChanged (contents, path);
+			GenerateJavaSource (
+				"JavaInteropRuntime.java",
+				new Dictionary<string, string> (StringComparer.Ordinal) {
+					{ "@MAIN_ASSEMBLY_NAME@", TargetName },
+				}
+			);
+
+			// We care only about environment variables here
+			var envBuilder = new EnvironmentBuilder (Log);
+			envBuilder.Read (Environments);
+			GenerateNativeApplicationConfigSources.AddDefaultEnvironmentVariables (envBuilder, HttpClientHandlerType, EnableSGenConcurrent);
+
+			var envVarNames = new StringBuilder ();
+			var envVarValues = new StringBuilder ();
+			foreach (var kvp in envBuilder.EnvironmentVariables) {
+				// All the strings already have double-quotes properly quoted, EnvironmentBuilder took care of that
+				AppendEnvVarEntry (envVarNames, kvp.Key);
+				AppendEnvVarEntry (envVarValues, kvp.Value);
+			}
+
+			var envVars = new Dictionary<string, string> (StringComparer.Ordinal) {
+				{ "@ENVIRONMENT_VAR_NAMES@", envVarNames.ToString () },
+				{ "@ENVIRONMENT_VAR_VALUES@", envVarValues.ToString () },
+			};
+
+			GenerateJavaSource (
+				"NativeAotEnvironmentVars.java",
+				envVars
+			);
 		}
 
 		// Create additional application java sources.
@@ -105,6 +137,26 @@ void Generate (NativeCodeGenStateObject codeGenState)
 			real_app_dir,
 			template => template.Replace ("// REGISTER_APPLICATION_AND_INSTRUMENTATION_CLASSES_HERE", regCallsWriter.ToString ())
 		);
+
+		void AppendEnvVarEntry (StringBuilder sb, string value)
+		{
+			sb.Append ("\t\t\"");
+			sb.Append (value);
+			sb.Append ("\",\n");
+		}
+
+		void GenerateJavaSource (string fileName, Dictionary<string, string> replacements)
+		{
+			var template = new StringBuilder (GetResource (fileName));
+
+			foreach (var kvp in replacements) {
+				template.Replace (kvp.Key, kvp.Value);
+			}
+
+			var path = Path.Combine (OutputDirectory, "src", "net", "dot", "jni", "nativeaot", fileName);
+			Log.LogDebugMessage ($"Writing: {path}");
+			Files.CopyIfStringChanged (template.ToString (), path);
+		}
 	}
 
 	string GetResource (string resource)

src/Xamarin.Android.Build.Tasks/Tasks/GenerateNativeAotEnvironmentAssemblerSources.cs

@@ -13,8 +13,6 @@ public class GenerateNativeAotEnvironmentAssemblerSources : AndroidTask
 
 	[Required]
 	public string RID { get; set; } = "";
-
-	public bool Debug { get; set; }
 	public ITaskItem[]? Environments { get; set; }
 	public string? HttpClientHandlerType { get; set; }
 
@@ -23,10 +21,9 @@ public override bool RunTask ()
 		var envBuilder = new EnvironmentBuilder (Log);
 		envBuilder.Read (Environments);
 
-		if (Debug) {
-			envBuilder.AddDefaultDebugBuildLogLevel ();
-		}
-		envBuilder.AddHttpClientHandlerType (HttpClientHandlerType);
+		// Environment variables are set by Java (code generated in the GenerateAdditionalProviderSources task)
+		// We still want to set system properties, if any
+		envBuilder.EnvironmentVariables.Clear ();
 
 		string abi = MonoAndroidHelper.RidToAbi (RID);
 		AndroidTargetArch targetArch = MonoAndroidHelper.RidToArch (RID);

src/Xamarin.Android.Build.Tasks/Tasks/GenerateNativeApplicationConfigSources.cs

@@ -50,6 +50,9 @@ public class GenerateNativeApplicationConfigSources : AndroidTask
 		[Required]
 		public bool TargetsCLR { get; set; }
 
+		[Required]
+		public string AndroidRuntime { get; set; } = "";
+
 		public bool EnableMarshalMethods { get; set; }
 		public bool EnableManagedMarshalMethodsLookup { get; set; }
 		public string? RuntimeConfigBinFilePath { get; set; }
@@ -76,8 +79,19 @@ bool _Debug {
 
 		static internal AndroidTargetArch GetAndroidTargetArchForAbi (string abi) => MonoAndroidHelper.AbiToTargetArch (abi);
 
+		AndroidRuntime androidRuntime;
+
+		internal static void AddDefaultEnvironmentVariables (EnvironmentBuilder envBuilder, string? httpClientHandlerType, bool enableSGenConcurrent)
+		{
+			envBuilder.AddDefaultMonoDebug ();
+			envBuilder.AddHttpClientHandlerType (httpClientHandlerType);
+			envBuilder.AddMonoGcParams (enableSGenConcurrent);
+		}
+
 		public override bool RunTask ()
 		{
+			androidRuntime = MonoAndroidHelper.ParseAndroidRuntime (AndroidRuntime);
+
 			bool usesMonoAOT = false;
 
 			if (!Enum.TryParse (PackageNamingPolicy, out PackageNamingPolicy pnp)) {
@@ -101,9 +115,15 @@ public override bool RunTask ()
 			if (_Debug) {
 				envBuilder.AddDefaultDebugBuildLogLevel ();
 			}
-			envBuilder.AddDefaultMonoDebug ();
-			envBuilder.AddHttpClientHandlerType (HttpClientHandlerType);
-			envBuilder.AddMonoGcParams (EnableSGenConcurrent);
+
+			if (androidRuntime != Xamarin.Android.Tasks.AndroidRuntime.NativeAOT) {
+				AddDefaultEnvironmentVariables (envBuilder, HttpClientHandlerType, EnableSGenConcurrent);
+			} else {
+				// NativeAOT sets all the environment variables from Java, we don't want to repeat that
+				// process in the native code. This is just a precaution, because NativeAOT builds should
+				// not even use this task.
+				envBuilder.EnvironmentVariables.Clear ();
+			}
 
 			global::Android.Runtime.BoundExceptionType boundExceptionType;
 			if (String.IsNullOrEmpty (BoundExceptionType) || MonoAndroidHelper.StringEquals (BoundExceptionType, "System", StringComparison.OrdinalIgnoreCase)) {

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/EnvironmentContentTests.cs

@@ -209,15 +209,30 @@ public void CheckHttpClientHandlerType ([Values] AndroidRuntime runtime)
 				proj.SetProperty ("AndroidHttpClientHandlerType", expectedDefaultValue);
 				Assert.IsTrue (b.Build (proj), "Build should have succeeded.");
 				var intermediateOutputDir = Path.Combine (Root, b.ProjectDirectory, proj.IntermediateOutputPath);
-				List<EnvironmentHelper.EnvironmentFile> envFiles = EnvironmentHelper.GatherEnvironmentFiles (intermediateOutputDir, supportedAbis, true, runtime);
-				Dictionary<string, string> envvars = EnvironmentHelper.ReadEnvironmentVariables (envFiles, runtime);
+
+				List<EnvironmentHelper.EnvironmentFile>? envFiles = null;
+				Dictionary<string, string> envvars;
+
+				if (runtime == AndroidRuntime.NativeAOT) {
+					envvars = EnvironmentHelper.ReadNativeAotEnvironmentVariables (intermediateOutputDir);
+				} else {
+					envFiles = EnvironmentHelper.GatherEnvironmentFiles (intermediateOutputDir, supportedAbis, true, runtime);
+					envvars = EnvironmentHelper.ReadEnvironmentVariables (envFiles, runtime);
+				}
+
 				Assert.IsTrue (envvars.ContainsKey (httpClientHandlerVarName), $"Environment should contain '{httpClientHandlerVarName}'.");
 				Assert.AreEqual (expectedDefaultValue, envvars[httpClientHandlerVarName]);
 
 				proj.SetProperty ("AndroidHttpClientHandlerType", expectedUpdatedValue);
 				Assert.IsTrue (b.Build (proj), "Second build should have succeeded.");
-				envFiles = EnvironmentHelper.GatherEnvironmentFiles (intermediateOutputDir, supportedAbis, true, runtime);
-				envvars = EnvironmentHelper.ReadEnvironmentVariables (envFiles, runtime);
+
+				if (runtime == AndroidRuntime.NativeAOT) {
+					envvars = EnvironmentHelper.ReadNativeAotEnvironmentVariables (intermediateOutputDir);
+				} else {
+					envFiles = EnvironmentHelper.GatherEnvironmentFiles (intermediateOutputDir, supportedAbis, true, runtime);
+					envvars = EnvironmentHelper.ReadEnvironmentVariables (envFiles, runtime);
+				}
+
 				Assert.IsTrue (envvars.ContainsKey (httpClientHandlerVarName), $"Environment should contain '{httpClientHandlerVarName}'.");
 				Assert.AreEqual (expectedUpdatedValue, envvars[httpClientHandlerVarName]);
 			}

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/EnvironmentHelper.cs

@@ -785,6 +785,71 @@ public static List<EnvironmentFile> GatherEnvironmentFiles (string outputDirecto
 			return environmentFiles;
 		}
 
+		public static Dictionary<string, string> ReadNativeAotEnvironmentVariables (string outputDirectoryRoot, bool required = true)
+		{
+			var ret = new Dictionary<string, string> (StringComparer.Ordinal);
+
+			string javaSourcePath = Path.Combine (outputDirectoryRoot, "android", "src", "net", "dot", "jni", "nativeaot", "NativeAotEnvironmentVars.java");
+			bool exists = File.Exists (javaSourcePath);
+			if (required) {
+				Assert.IsTrue (exists, $"NativeAOT Java source with environment variables does not exist: {javaSourcePath}");
+			} else if (!exists) {
+				return ret;
+			}
+
+			var names = new List<string> ();
+			var values = new List<string> ();
+			bool collectingNames = false;
+			bool collectingValues = false;
+			int lineNum = 0;
+
+			foreach (string l in File.ReadAllLines (javaSourcePath)) {
+				lineNum++;
+				string line = l.Trim ();
+				switch (line) {
+					case "static String[] envNames = new String[] {":
+						collectingNames = true;
+						collectingValues = false;
+						continue;
+
+					case "static String[] envValues = new String[] {":
+						collectingValues = true;
+						collectingNames = false;
+						continue;
+
+					case "};":
+						collectingValues = false;
+						collectingNames = false;
+						continue;
+
+					case "":
+						continue;
+				}
+
+				if (!collectingValues && !collectingNames) {
+					continue;
+				}
+
+				Assert.IsTrue (line[0] == '"', $"Line {lineNum} in '{javaSourcePath}' doesn't start with a double quote: '{line}'");
+				Assert.IsTrue (line[line.Length - 1] == ',', $"Line {lineNum} in '{javaSourcePath}' doesn't end with a comma: '{line}'");
+				Assert.IsTrue (line[line.Length - 2] == '"', $"Line {lineNum} in '{javaSourcePath}' doesn't close the quoted string properly: '{line}'");
+
+				string data = line.Substring (1, line.Length - 3);
+				if (collectingNames) {
+					names.Add (data);
+				} else if (collectingValues) {
+					values.Add (data);
+				}
+			}
+
+			Assert.AreEqual (names.Count, values.Count, "Environment variable name and value arrays aren't of the same size in '{javaSourcePath}'");
+			for (int i = 0; i < names.Count; i++) {
+				ret.Add (names[i], values[i]);
+			}
+
+			return ret;
+		}
+
 		public static void AssertValidEnvironmentSharedLibrary (string outputDirectoryRoot, string sdkDirectory, string ndkDirectory, string supportedAbis, AndroidRuntime runtime)
 		{
 			NdkTools ndk = NdkTools.Create (ndkDirectory);

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -1662,6 +1662,9 @@ because xbuild doesn't support framework reference assemblies.
   <GenerateAdditionalProviderSources
       AdditionalProviderSources="@(_AdditionalProviderSources)"
       AndroidRuntime="$(_AndroidRuntime)"
+      Environments="@(_EnvironmentFiles)"
+      HttpClientHandlerType="$(AndroidHttpClientHandlerType)"
+      EnableSGenConcurrent="$(AndroidEnableSGenConcurrent)"
       CodeGenerationTarget="$(_AndroidJcwCodegenTarget)"
       IntermediateOutputDirectory="$(IntermediateOutputPath)"
       OutputDirectory="$(IntermediateOutputPath)android"
@@ -1906,6 +1909,7 @@ because xbuild doesn't support framework reference assemblies.
       EnableManagedMarshalMethodsLookup="$(_AndroidUseManagedMarshalMethodsLookup)"
       CustomBundleConfigFile="$(AndroidBundleConfigurationFile)"
       TargetsCLR="$(_AndroidUseCLR)"
+      AndroidRuntime="$(_AndroidRuntime)"
       ProjectRuntimeConfigFilePath="$(ProjectRuntimeConfigFilePath)"
       >
   </GenerateNativeApplicationConfigSources>