[nativeaot] Add more compatibility with CoreCLR and MonoVM hosts (#10498)

Add more compatibility with the MonoVM and CoreCLR host environments to
the NativeAOT host.

It is important that the applications created for MonoVM, then potentially
migrated to CoreCLR, found themselves running in an environment as closely
resembling the one they were developed and tested in.

Add the following to the NativeAOT runtime:

  * Set up environment variables found in both MonoVM and CoreCLR runtimes.
  * Create XDG directories expected to exist before managed application
    code is invoked for the first time.

Additionally, stop linking shared version of the `libc++` library, instead use the static one.
This shrinks the sample package size by ~8mb and is also a requirement for applications
that may themselves use `libc++`, since that could cause conflicts with the binaries produced
by the NativeAOT compiler.

Author: grendello

src/Microsoft.Android.Runtime.NativeAOT/Android.Runtime.NativeAOT/JavaInteropRuntime.cs

@@ -41,11 +41,11 @@ static void JNI_OnUnload (IntPtr vm, IntPtr reserved)
 	}
 
 	[DllImport("xa-internal-api")]
-	static extern void XA_Host_NativeAOT_OnInit ();
+	static extern void XA_Host_NativeAOT_OnInit (IntPtr language, IntPtr filesDir, IntPtr cacheDir);
 
 	// symbol name from `$(IntermediateOutputPath)obj/Release/osx-arm64/h-classes/net_dot_jni_hello_JavaInteropRuntime.h`
 	[UnmanagedCallersOnly (EntryPoint="Java_net_dot_jni_nativeaot_JavaInteropRuntime_init")]
-	static void init (IntPtr jnienv, IntPtr klass, IntPtr classLoader)
+	static void init (IntPtr jnienv, IntPtr klass, IntPtr classLoader, IntPtr language, IntPtr filesDir, IntPtr cacheDir)
 	{
 		JniTransition   transition  = default;
 		try {
@@ -65,7 +65,7 @@ static void init (IntPtr jnienv, IntPtr klass, IntPtr classLoader)
 
 			// Entry point into Mono.Android.dll
 			JNIEnvInit.InitializeJniRuntime (runtime);
-			XA_Host_NativeAOT_OnInit ();
+			XA_Host_NativeAOT_OnInit (language, filesDir, cacheDir);
 
 			transition  = new JniTransition (jnienv);
 

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

@@ -11,5 +11,5 @@ public class JavaInteropRuntime {
     private JavaInteropRuntime() {
     }
 
-    public static native void init(ClassLoader classLoader);
+    public static native void init(ClassLoader classLoader, String language, String filesDir, String cacheDir);
 }

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

@@ -1,5 +1,6 @@
 package net.dot.jni.nativeaot;
 
+import java.util.Locale;
 import android.system.ErrnoException;
 import android.system.Os;
 import android.util.Log;
@@ -27,20 +28,14 @@ public void attachInfo(android.content.Context context, android.content.pm.Provi
             ApplicationRegistration.Context = context;
         }
 
-        // Set environment variables
-        try {
-            String filesDir = context.getFilesDir().getAbsolutePath();
-            String cacheDir = context.getCacheDir().getAbsolutePath();
-            Os.setenv("HOME", filesDir, true);
-            Os.setenv("TMPDIR", cacheDir, true);
-        } catch (ErrnoException e) {
-            Log.e(TAG, "Failed to set environment variables", e);
-        }
-
-        ClassLoader loader  = context.getClassLoader ();
+        ClassLoader loader = context.getClassLoader ();
+        Locale locale = Locale.getDefault ();
+        String language = locale.getLanguage () + "-" + locale.getCountry ();
+        String filesDir = context.getFilesDir().getAbsolutePath();
+        String cacheDir = context.getCacheDir().getAbsolutePath();
 
         // Initialize .NET runtime
-        JavaInteropRuntime.init(loader);
+        JavaInteropRuntime.init(loader, language, filesDir, cacheDir);
         // NOTE: only required for custom applications
         ApplicationRegistration.registerApplications();
         super.attachInfo (context, info);
@@ -70,4 +65,4 @@ public int delete(android.net.Uri uri, String where, String[] whereArgs) {
     public int update(android.net.Uri uri, android.content.ContentValues values, String where, String[] whereArgs) {
         throw new RuntimeException ("This operation is not supported.");
     }
-}
+}

src/native/clr/host/host.cc

@@ -15,6 +15,7 @@
 #include <host/gc-bridge.hh>
 #include <host/fastdev-assemblies.hh>
 #include <host/host.hh>
+#include <host/host-environment-clr.hh>
 #include <host/host-jni.hh>
 #include <host/host-util.hh>
 #include <host/os-bridge.hh>
@@ -285,35 +286,6 @@ void Host::gather_assemblies_and_libraries (jstring_array_wrapper& runtimeApks,
 	}
 }
 
-void Host::create_xdg_directory (jstring_wrapper& home, size_t home_len, std::string_view const& relative_path, std::string_view const& environment_variable_name) noexcept
-{
-	static_local_string<SENSIBLE_PATH_MAX> dir (home_len + relative_path.length ());
-	Util::path_combine (dir, home.get_string_view (), relative_path);
-
-	log_debug (LOG_DEFAULT, "Creating XDG directory: {}"sv, optional_string (dir.get ()));
-	int rv = Util::create_directory (dir.get (), Constants::DEFAULT_DIRECTORY_MODE);
-	if (rv < 0 && errno != EEXIST) {
-		log_warn (LOG_DEFAULT, "Failed to create XDG directory {}. {}"sv, optional_string (dir.get ()), strerror (errno));
-	}
-
-	if (!environment_variable_name.empty ()) {
-		setenv (environment_variable_name.data (), dir.get (), 1);
-	}
-}
-
-void Host::create_xdg_directories_and_environment (jstring_wrapper &homeDir) noexcept
-{
-	size_t home_len = strlen (homeDir.get_cstr ());
-
-	constexpr auto XDG_DATA_HOME = "XDG_DATA_HOME"sv;
-	constexpr auto HOME_PATH = ".local/share"sv;
-	create_xdg_directory (homeDir, home_len, HOME_PATH, XDG_DATA_HOME);
-
-	constexpr auto XDG_CONFIG_HOME = "XDG_CONFIG_HOME"sv;
-	constexpr auto CONFIG_PATH = ".config"sv;
-	create_xdg_directory (homeDir, home_len, CONFIG_PATH, XDG_CONFIG_HOME);
-}
-
 [[gnu::always_inline]]
 auto Host::create_delegate (
 	std::string_view const& assembly_name, std::string_view const& type_name,
@@ -434,20 +406,19 @@ void Host::Java_mono_android_Runtime_initInternal (
 	}
 
 	jstring_array_wrapper applicationDirs (env, appDirs);
-
-	jstring_wrapper jstr (env, lang);
-	Util::set_environment_variable ("LANG"sv, jstr);
-
-	jstring_wrapper &home = applicationDirs[Constants::APP_DIRS_FILES_DIR_INDEX];
-	Util::set_environment_variable_for_directory ("TMPDIR"sv, applicationDirs[Constants::APP_DIRS_CACHE_DIR_INDEX]);
-	Util::set_environment_variable_for_directory ("HOME"sv, home);
-	create_xdg_directories_and_environment (home);
+	jstring_wrapper language (env, lang);
+	jstring_wrapper &files_dir = applicationDirs[Constants::APP_DIRS_FILES_DIR_INDEX];
+	HostEnvironment::setup_environment (
+		language,
+		files_dir,
+		applicationDirs[Constants::APP_DIRS_CACHE_DIR_INDEX]
+	);
 
 	java_TimeZone = RuntimeUtil::get_class_from_runtime_field (env, runtimeClass, "java_util_TimeZone"sv, true);
 
 	AndroidSystem::detect_embedded_dso_mode (applicationDirs);
 	AndroidSystem::set_running_in_emulator (isEmulator);
-	AndroidSystem::set_primary_override_dir (home);
+	AndroidSystem::set_primary_override_dir (files_dir);
 	AndroidSystem::create_update_dir (AndroidSystem::get_primary_override_dir ());
 	AndroidSystem::setup_environment ();
 

src/native/clr/include/host/host-environment.hh

@@ -1,11 +1,16 @@
 #pragma once
 
+#include <jni.h>
+
 #include <cerrno>
 #include <cstdlib>
 #include <cstring>
 #include <string_view>
 
+#include <runtime-base/jni-wrappers.hh>
 #include <runtime-base/logger.hh>
+#include <runtime-base/strings.hh>
+#include <runtime-base/util.hh>
 
 struct AppEnvironmentVariable;
 
@@ -18,16 +23,19 @@ namespace xamarin::android {
 		[[gnu::flatten, gnu::always_inline]]
 		static void set_variable (const char *name, const char *value) noexcept
 		{
-			log_debug (LOG_DEFAULT, " Variable {} = '{}'", optional_string (name), optional_string (value));
-			if (::setenv (name, value, 1) < 0) {
-				log_warn (LOG_DEFAULT, "Failed to set environment variable '{}': {}", name, ::strerror (errno));
-			}
+			Util::set_environment_variable (name, value);
 		}
 
 		[[gnu::flatten, gnu::always_inline]]
 		static void set_variable (std::string_view const& name, std::string_view const& value) noexcept
 		{
-			set_variable (name.data (), value.data ());
+			Util::set_environment_variable (name.data (), value.data ());
+		}
+
+		[[gnu::flatten, gnu::always_inline]]
+		static void set_variable (std::string_view const& name, jstring_wrapper &value) noexcept
+		{
+			Util::set_environment_variable (name.data (), value);
 		}
 
 		[[gnu::flatten, gnu::always_inline]]
@@ -72,5 +80,47 @@ namespace xamarin::android {
 				setter (var_name, var_value);
 			}
 		}
+
+	private:
+		[[gnu::flatten, gnu::always_inline]]
+		static void create_xdg_directory (jstring_wrapper &home, size_t home_len, std::string_view const& relative_path, std::string_view const& environment_variable_name) noexcept
+		{
+			static_local_string<SENSIBLE_PATH_MAX> dir (home_len + relative_path.length ());
+			Util::path_combine (dir, home.get_string_view (), relative_path);
+
+			log_debug (LOG_DEFAULT, "Creating XDG directory: {}"sv, optional_string (dir.get ()));
+			int rv = Util::create_directory (dir.get (), Constants::DEFAULT_DIRECTORY_MODE);
+			if (rv < 0 && errno != EEXIST) {
+				log_warn (LOG_DEFAULT, "Failed to create XDG directory {}. {}"sv, optional_string (dir.get ()), strerror (errno));
+			}
+
+			if (!environment_variable_name.empty ()) {
+				set_variable (environment_variable_name.data (), dir.get ());
+			}
+		}
+
+		[[gnu::flatten, gnu::always_inline]]
+		static void create_xdg_directories_and_environment (jstring_wrapper &homeDir) noexcept
+		{
+			size_t home_len = strlen (homeDir.get_cstr ());
+
+			constexpr auto XDG_DATA_HOME = "XDG_DATA_HOME"sv;
+			constexpr auto HOME_PATH = ".local/share"sv;
+			create_xdg_directory (homeDir, home_len, HOME_PATH, XDG_DATA_HOME);
+
+			constexpr auto XDG_CONFIG_HOME = "XDG_CONFIG_HOME"sv;
+			constexpr auto CONFIG_PATH = ".config"sv;
+			create_xdg_directory (homeDir, home_len, CONFIG_PATH, XDG_CONFIG_HOME);
+		}
+
+	public:
+		[[gnu::flatten, gnu::always_inline]]
+		static void setup_environment (jstring_wrapper &language, jstring_wrapper &files_dir, jstring_wrapper &cache_dir) noexcept
+		{
+			set_variable ("LANG"sv, language);
+			Util::set_environment_variable_for_directory ("TMPDIR"sv, cache_dir);
+			Util::set_environment_variable_for_directory ("HOME"sv, files_dir);
+			create_xdg_directories_and_environment (files_dir);
+		}
 	};
 }

src/native/clr/include/host/host.hh

@@ -32,8 +32,6 @@ namespace xamarin::android {
 		}
 
 	private:
-		static void create_xdg_directory (jstring_wrapper& home, size_t home_len, std::string_view const& relative_path, std::string_view const& environment_variable_name) noexcept;
-		static void create_xdg_directories_and_environment (jstring_wrapper &homeDir) noexcept;
 		static auto zip_scan_callback (std::string_view const& apk_path, int apk_fd, dynamic_local_string<SENSIBLE_PATH_MAX> const& entry_name, uint32_t offset, uint32_t size) -> bool;
 		static void gather_assemblies_and_libraries (jstring_array_wrapper& runtimeApks, bool have_split_apks);
 		static void scan_filesystem_for_assemblies_and_libraries () noexcept;

src/native/clr/include/runtime-base/util.hh

@@ -151,11 +151,28 @@ namespace xamarin::android {
 			return get_file_size_at (dirfd, file_name.data ());
 		}
 
+		[[gnu::flatten, gnu::always_inline]]
+		static void set_environment_variable (const char *name, const char *value) noexcept
+		{
+			log_debug (LOG_DEFAULT, "Setting environment variable {} = '{}'", optional_string (name), optional_string (value));
+			if (::setenv (name, value, 1) < 0) {
+				log_warn (LOG_DEFAULT, "Failed to set environment variable '{}': {}", name, ::strerror (errno));
+			}
+		}
+
+		[[gnu::flatten, gnu::always_inline]]
 		static void set_environment_variable (std::string_view const& name, jstring_wrapper& value) noexcept
 		{
-			::setenv (name.data (), value.get_cstr (), 1);
+			set_environment_variable (name.data (), value.get_cstr ());
 		}
 
+		[[gnu::flatten, gnu::always_inline]]
+		static void set_environment_variable (std::string_view const& name, std::string_view const& value) noexcept
+		{
+			set_environment_variable (name.data (), value.data ());
+		}
+
+		[[gnu::flatten, gnu::always_inline]]
 		static void set_environment_variable_for_directory (std::string_view const& name, jstring_wrapper& value, bool createDirectory, mode_t mode) noexcept
 		{
 			if (createDirectory) {
@@ -167,6 +184,7 @@ namespace xamarin::android {
 			set_environment_variable (name, value);
 		}
 
+		[[gnu::flatten, gnu::always_inline]]
 		static void set_environment_variable_for_directory (std::string_view const& name, jstring_wrapper &value) noexcept
 		{
 			set_environment_variable_for_directory (name, value, true, Constants::DEFAULT_DIRECTORY_MODE);

src/native/nativeaot/host/host-environment.cc

@@ -14,7 +14,6 @@ extern "C" {
 void HostEnvironment::init () noexcept
 {
 	if (__naot_android_app_environment_variable_count > 0) {
-		log_debug (LOG_DEFAULT, "Setting environment variables ({})", __naot_android_app_environment_variable_count);
 		set_values<set_variable> (
 			__naot_android_app_environment_variable_count,
 			__naot_android_app_environment_variables,
@@ -26,7 +25,6 @@ void HostEnvironment::init () noexcept
 		return;
 	}
 
-	log_debug (LOG_DEFAULT, "Setting system properties ({})", __naot_android_app_system_property_count);
 	set_values<set_system_property> (
 		__naot_android_app_system_property_count,
 		__naot_android_app_system_properties,

src/native/nativeaot/host/host-jni.cc

@@ -1,3 +1,5 @@
+#include <jni.h>
+
 #include <host/host-jni.hh>
 #include <host/host-nativeaot.hh>
 #include <runtime-base/logger.hh>
@@ -9,7 +11,7 @@ auto XA_Host_NativeAOT_JNI_OnLoad (JavaVM *vm, void *reserved) -> int
 	return Host::Java_JNI_OnLoad (vm, reserved);
 }
 
-void XA_Host_NativeAOT_OnInit ()
+void XA_Host_NativeAOT_OnInit (jstring language, jstring filesDir, jstring cacheDir)
 {
-	Host::OnInit ();
+	Host::OnInit (language, filesDir, cacheDir);
 }

src/native/nativeaot/host/host.cc

@@ -46,10 +46,16 @@ auto HostCommon::Java_JNI_OnLoad (JavaVM *vm, void *reserved) noexcept -> jint
 	return JNI_VERSION_1_6;
 }
 
-void Host::OnInit () noexcept
+void Host::OnInit (jstring language, jstring filesDir, jstring cacheDir) noexcept
 {
 	JNIEnv *env = OSBridge::ensure_jnienv ();
 	jclass runtimeClass = env->FindClass ("mono/android/Runtime");
+
+	jstring_wrapper language_js (env, language);
+	jstring_wrapper files_dir (env, filesDir);
+	jstring_wrapper cache_dir (env, cacheDir);
+	HostEnvironment::setup_environment (language_js, files_dir, cache_dir);
+
 	OSBridge::initialize_on_runtime_init (env, runtimeClass);
 	GCBridge::initialize_on_runtime_init (env, runtimeClass);
 	BridgeProcessing::naot_initialize_on_runtime_init (env);