tests/tests/jni/src/android/jni/cts/LinkerNamespacesHelper.java - platform/cts - Git at Google

 /*
  * Copyright (C) 2016 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package android.jni.cts;

 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.os.Build;

 import androidx.test.InstrumentationRegistry;

 import dalvik.system.PathClassLoader;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
 import java.io.FilenameFilter;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;

 class LinkerNamespacesHelper {
     private final static String PUBLIC_CONFIG_DIR = "/system/etc/";
     private final static String PRODUCT_CONFIG_DIR = "/product/etc/";
     private final static String SYSTEM_CONFIG_FILE = PUBLIC_CONFIG_DIR + "public.libraries.txt";
     private final static Pattern EXTENSION_CONFIG_FILE_PATTERN = Pattern.compile(
             "public\\.libraries-([A-Za-z0-9\\-_.]+)\\.txt");
     private final static String VENDOR_CONFIG_FILE = "/vendor/etc/public.libraries.txt";
     private final static String[] PUBLIC_SYSTEM_LIBRARIES = {
         "libaaudio.so",
         "libamidi.so",
         "libandroid.so",
         "libbinder_ndk.so",
         "libc.so",
         "libcamera2ndk.so",
         "libdl.so",
         "libEGL.so",
         "libGLESv1_CM.so",
         "libGLESv2.so",
         "libGLESv3.so",
         "libjnigraphics.so",
         "liblog.so",
         "libmediandk.so",
         "libm.so",
         "libnativewindow.so",
         "libneuralnetworks.so",
         "libOpenMAXAL.so",
         "libOpenSLES.so",
         "libRS.so",
         "libstdc++.so",
         "libsync.so",
         "libvulkan.so",
         "libz.so"
     };

     // System libraries that may exist in some types of builds.
     private final static String[] OPTIONAL_SYSTEM_LIBRARIES = {
       "libclang_rt.hwasan-aarch64-android.so"
     };

     // Libraries listed in public.libraries.android.txt, located in /apex/com.android.art/${LIB}
     private final static String[] PUBLIC_ART_LIBRARIES = {
         "libicui18n.so",
         "libicuuc.so",
         "libnativehelper.so",
         "libsigchain.so"
     };

     // The grey-list.
     private final static String[] PRIVATE_SYSTEM_LIBRARIES = {
         "libandroid_runtime.so",
         "libbinder.so",
         "libcrypto.so",
         "libcutils.so",
         "libexpat.so",
         "libgui.so",
         "libmedia.so",
         "libskia.so",
         "libssl.so",
         "libstagefright.so",
         "libsqlite.so",
         "libui.so",
         "libutils.so",
         "libvorbisidec.so",
     };

     private final static String WEBVIEW_PLAT_SUPPORT_LIB = "libwebviewchromium_plat_support.so";

     static enum Bitness { ALL, ONLY_32, ONLY_64 }

     private static List<String> readPublicLibrariesFile(File file) throws IOException {
         List<String> libs = new ArrayList<>();
         if (file.exists()) {
             try (BufferedReader br = new BufferedReader(new FileReader(file))) {
                 String line;
                 final boolean is64Bit = android.os.Process.is64Bit();
                 while ((line = br.readLine()) != null) {
                     line = line.trim();
                     if (line.isEmpty() || line.startsWith("#")) {
                         continue;
                     }
                     String[] tokens = line.split(" ");
                     if (tokens.length < 1 || tokens.length > 3) {
                         throw new RuntimeException("Malformed line: '" + line + "' in " + file);
                     }
                     String soname = tokens[0];
                     Bitness bitness = Bitness.ALL;
                     int i = tokens.length;
                     while(--i >= 1) {
                         if (tokens[i].equals("nopreload")) {
                             continue;
                         }
                         else if (tokens[i].equals("32") || tokens[i].equals("64")) {
                             if (bitness != Bitness.ALL) {
                                 throw new RuntimeException("Malformed line: '" + line +
                                         "' in " + file + ". Bitness can be specified only once");
                             }
                             bitness = tokens[i].equals("32") ? Bitness.ONLY_32 : Bitness.ONLY_64;
                         } else {
                             throw new RuntimeException("Unrecognized token '" + tokens[i] +
                                   "' in " + file);
                         }
                     }
                     if ((is64Bit && bitness == Bitness.ONLY_32) ||
                         (!is64Bit && bitness == Bitness.ONLY_64)) {
                         // skip unsupported bitness
                         continue;
                     }
                     libs.add(soname);
                 }
             }
         }
         return libs;
     }

     private static String readExtensionConfigFiles(String configDir, List<String> libs) throws IOException {
         File[] configFiles = new File(configDir).listFiles(
                 new FilenameFilter() {
                     public boolean accept(File dir, String name) {
                         return EXTENSION_CONFIG_FILE_PATTERN.matcher(name).matches();
                     }
                 });
         if (configFiles == null) return null;

         for (File configFile: configFiles) {
             String fileName = configFile.toPath().getFileName().toString();
             Matcher configMatcher = EXTENSION_CONFIG_FILE_PATTERN.matcher(fileName);
             if (configMatcher.matches()) {
                 String companyName = configMatcher.group(1);
                 // a lib in public.libraries-acme.txt should be
                 // libFoo.acme.so
                 List<String> libNames = readPublicLibrariesFile(configFile);
                 for (String lib : libNames) {
                     if (lib.endsWith("." + companyName + ".so")) {
                         libs.add(lib);
                     } else {
                         return "Library \"" + lib + "\" in " + configFile.toString()
                                 + " must have company name " + companyName + " as suffix.";
                     }
                 }
             }
         }
         return null;
     }

     public static String runAccessibilityTest() throws IOException {
         List<String> systemLibs = new ArrayList<>();
         List<String> artApexLibs = new ArrayList<>();

         Collections.addAll(systemLibs, PUBLIC_SYSTEM_LIBRARIES);
         Collections.addAll(systemLibs, OPTIONAL_SYSTEM_LIBRARIES);
 	// System path could contain public ART libraries on foreign arch. http://b/149852946
         if (isForeignArchitecture()) {
             Collections.addAll(systemLibs, PUBLIC_ART_LIBRARIES);
         }

         if (InstrumentationRegistry.getContext().getPackageManager().
                 hasSystemFeature(PackageManager.FEATURE_WEBVIEW)) {
             systemLibs.add(WEBVIEW_PLAT_SUPPORT_LIB);
         }

         Collections.addAll(artApexLibs, PUBLIC_ART_LIBRARIES);

         // Check if /system/etc/public.libraries-company.txt and /product/etc/public.libraries
         // -company.txt files are well-formed. The libraries however are not loaded for test;
         // It is done in another test CtsUsesNativeLibraryTest because since Android S those libs
         // are not available unless they are explicited listed in the app manifest.

         List<String> oemLibs = new ArrayList<>();
         String oemLibsError = readExtensionConfigFiles(PUBLIC_CONFIG_DIR, oemLibs);
         if (oemLibsError != null) return oemLibsError;

         // PRODUCT libs that passed are also available
         List<String> productLibs = new ArrayList<>();
         String productLibsError = readExtensionConfigFiles(PRODUCT_CONFIG_DIR, productLibs);
         if (productLibsError != null) return productLibsError;

         // Make sure that the libs in grey-list are not exposed to apps. In fact, it
         // would be better for us to run this check against all system libraries which
         // are not NDK libs, but grey-list libs are enough for now since they have been
         // the most popular violators.
         Set<String> greyListLibs = new HashSet<>();
         Collections.addAll(greyListLibs, PRIVATE_SYSTEM_LIBRARIES);
         // Note: check for systemLibs isn't needed since we already checked
         // /system/etc/public.libraries.txt against NDK and
         // /system/etc/public.libraries-<company>.txt against lib<name>.<company>.so.
         List<String> vendorLibs = readPublicLibrariesFile(new File(VENDOR_CONFIG_FILE));
         for (String lib : vendorLibs) {
             if (greyListLibs.contains(lib)) {
                 return "Internal library \"" + lib + "\" must not be available to apps.";
             }
         }

         return runAccessibilityTestImpl(systemLibs.toArray(new String[systemLibs.size()]),
                                         artApexLibs.toArray(new String[artApexLibs.size()]));
     }

     private static native String runAccessibilityTestImpl(String[] publicSystemLibs,
                                                           String[] publicRuntimeLibs);

     private static void invokeIncrementGlobal(Class<?> clazz) throws Exception {
         clazz.getMethod("incrementGlobal").invoke(null);
     }
     private static int invokeGetGlobal(Class<?> clazz) throws Exception  {
         return (Integer)clazz.getMethod("getGlobal").invoke(null);
     }

     private static ApplicationInfo getApplicationInfo(String packageName) {
         PackageManager pm = InstrumentationRegistry.getContext().getPackageManager();
         try {
             return pm.getApplicationInfo(packageName, 0);
         } catch (NameNotFoundException nnfe) {
             throw new RuntimeException(nnfe);
         }
     }

     private static String getSourcePath(String packageName) {
         String sourcePath = getApplicationInfo(packageName).sourceDir;
         if (sourcePath == null) {
             throw new IllegalStateException("No source path path found for " + packageName);
         }
         return sourcePath;
     }

     private static String getNativePath(String packageName) {
         String nativePath = getApplicationInfo(packageName).nativeLibraryDir;
         if (nativePath == null) {
             throw new IllegalStateException("No native path path found for " + packageName);
         }
         return nativePath;
     }

     private static boolean isAlreadyOpenedError(UnsatisfiedLinkError e, String libFilePath) {
         // If one of the public system libraries are already opened in the bootclassloader, consider
         // this try as success, because dlopen to the lib is successful.
         String baseName = new File(libFilePath).getName();
         return e.getMessage().contains("Shared library \"" + libFilePath +
             "\" already opened by ClassLoader") &&
             Arrays.asList(PUBLIC_SYSTEM_LIBRARIES).contains(baseName);
     }

     private static String loadWithSystemLoad(String libFilePath) {
         try {
             System.load(libFilePath);
         } catch (UnsatisfiedLinkError e) {
             // all other exceptions are just thrown
             if (!isAlreadyOpenedError(e, libFilePath)) {
                 return "System.load() UnsatisfiedLinkError: " + e.getMessage();
             }
         }
         return "";
     }

     private static String loadWithSystemLoadLibrary(String libFileName) {
         // Drop 'lib' and '.so' from the base name
         String libName = libFileName.substring(3, libFileName.length()-3);
         try {
             System.loadLibrary(libName);
         } catch (UnsatisfiedLinkError e) {
             if (!isAlreadyOpenedError(e, libFileName)) {
                 return "System.loadLibrary(\"" + libName + "\") UnsatisfiedLinkError: " +
                     e.getMessage();
             }
         }
         return "";
     }

     // Verify the behaviour of native library loading in class loaders.
     // In this test:
     //    - libjninamespacea1, libjninamespacea2 and libjninamespaceb depend on libjnicommon
     //    - loaderA will load ClassNamespaceA1 (loading libjninamespacea1)
     //    - loaderA will load ClassNamespaceA2 (loading libjninamespacea2)
     //    - loaderB will load ClassNamespaceB (loading libjninamespaceb)
     //    - incrementGlobal/getGlobal operate on a static global from libjnicommon
     //      and each class should get its own view on it.
     //
     // This is a test case for 2 different scenarios:
     //    - loading native libraries in different class loaders
     //    - loading native libraries in the same class loader
     // Ideally we would have 2 different tests but JNI doesn't allow loading the same library in
     // different class loaders. So to keep the number of native libraries manageable we just
     // re-use the same class loaders for the two tests.
     public static String runClassLoaderNamespaces() throws Exception {
         // Test for different class loaders.
         // Verify that common dependencies get a separate copy in each class loader.
         // libjnicommon should be loaded twice:
         // in the namespace for loaderA and the one for loaderB.
         String apkPath = getSourcePath("android.jni.cts");
         String nativePath = getNativePath("android.jni.cts");
         PathClassLoader loaderA = new PathClassLoader(
                 apkPath, nativePath, ClassLoader.getSystemClassLoader());
         Class<?> testA1Class = loaderA.loadClass("android.jni.cts.ClassNamespaceA1");
         PathClassLoader loaderB = new PathClassLoader(
                 apkPath, nativePath, ClassLoader.getSystemClassLoader());
         Class<?> testBClass = loaderB.loadClass("android.jni.cts.ClassNamespaceB");

         int globalA1 = invokeGetGlobal(testA1Class);
         int globalB = invokeGetGlobal(testBClass);
         if (globalA1 != 0 || globalB != 0) {
             return "Expected globals to be 0/0: globalA1=" + globalA1 + " globalB=" + globalB;
         }

         invokeIncrementGlobal(testA1Class);
         globalA1 = invokeGetGlobal(testA1Class);
         globalB = invokeGetGlobal(testBClass);
         if (globalA1 != 1 || globalB != 0) {
             return "Expected globals to be 1/0: globalA1=" + globalA1 + " globalB=" + globalB;
         }

         invokeIncrementGlobal(testBClass);
         globalA1 = invokeGetGlobal(testA1Class);
         globalB = invokeGetGlobal(testBClass);
         if (globalA1 != 1 || globalB != 1) {
             return "Expected globals to be 1/1: globalA1=" + globalA1 + " globalB=" + globalB;
         }

         // Test for the same class loaders.
         // Verify that if we load ClassNamespaceA2 into loaderA we get the same view on the
         // globals.
         Class<?> testA2Class = loaderA.loadClass("android.jni.cts.ClassNamespaceA2");

         int globalA2 = invokeGetGlobal(testA2Class);
         if (globalA1 != 1 || globalA2 !=1) {
             return "Expected globals to be 1/1: globalA1=" + globalA1 + " globalA2=" + globalA2;
         }

         invokeIncrementGlobal(testA1Class);
         globalA1 = invokeGetGlobal(testA1Class);
         globalA2 = invokeGetGlobal(testA2Class);
         if (globalA1 != 2 || globalA2 != 2) {
             return "Expected globals to be 2/2: globalA1=" + globalA1 + " globalA2=" + globalA2;
         }

         invokeIncrementGlobal(testA2Class);
         globalA1 = invokeGetGlobal(testA1Class);
         globalA2 = invokeGetGlobal(testA2Class);
         if (globalA1 != 3 || globalA2 != 3) {
             return "Expected globals to be 2/2: globalA1=" + globalA1 + " globalA2=" + globalA2;
         }
         // On success we return null.
         return null;
     }

     public static String runDlopenPublicLibraries() {
         String error = null;
         List<String> publicLibs = new ArrayList<>();
         Collections.addAll(publicLibs, PUBLIC_SYSTEM_LIBRARIES);
         Collections.addAll(publicLibs, PUBLIC_ART_LIBRARIES);
         for (String lib : publicLibs) {
             String result = LinkerNamespacesHelper.tryDlopen(lib);
             if (result != null) {
                 if (error == null) {
                     error = "";
                 }
                 error += result + "\n";
             }
         }
         return error;
     }

     public static native String tryDlopen(String lib);

     private static boolean isForeignArchitecture() {
         int libAbi = getLibAbi();
         String cpuAbi = android.os.SystemProperties.get("ro.product.cpu.abi");
         if ((libAbi == 1 || libAbi == 2) && !cpuAbi.startsWith("arm")) {
             return true;
         } else if ((libAbi == 3 || libAbi == 4) && !cpuAbi.startsWith("x86")) {
             return true;
         }
         return false;
     }

     /**
      * @return ABI type of the JNI library. 1: ARM64, 2:ARM, 3: x86_64, 4: x86, 0: others
      */
     private static native int getLibAbi();
 }

 class ClassNamespaceA1 {
     static {
         System.loadLibrary("jninamespacea1");
     }

     public static native void incrementGlobal();
     public static native int getGlobal();
 }

 class ClassNamespaceA2 {
     static {
         System.loadLibrary("jninamespacea2");
     }

     public static native void incrementGlobal();
     public static native int getGlobal();
 }

 class ClassNamespaceB {
     static {
         System.loadLibrary("jninamespaceb");
     }

     public static native void incrementGlobal();
     public static native int getGlobal();
 }
	/*
	* Copyright (C) 2016 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package android.jni.cts;

	import android.content.pm.ApplicationInfo;
	import android.content.pm.PackageManager;
	import android.content.pm.PackageManager.NameNotFoundException;
	import android.os.Build;

	import androidx.test.InstrumentationRegistry;

	import dalvik.system.PathClassLoader;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.FileReader;
	import java.io.FilenameFilter;
	import java.io.IOException;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collections;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Set;
	import java.util.regex.Matcher;
	import java.util.regex.Pattern;

	class LinkerNamespacesHelper {
	private final static String PUBLIC_CONFIG_DIR = "/system/etc/";
	private final static String PRODUCT_CONFIG_DIR = "/product/etc/";
	private final static String SYSTEM_CONFIG_FILE = PUBLIC_CONFIG_DIR + "public.libraries.txt";
	private final static Pattern EXTENSION_CONFIG_FILE_PATTERN = Pattern.compile(
	"public\\.libraries-([A-Za-z0-9\\-_.]+)\\.txt");
	private final static String VENDOR_CONFIG_FILE = "/vendor/etc/public.libraries.txt";
	private final static String[] PUBLIC_SYSTEM_LIBRARIES = {
	"libaaudio.so",
	"libamidi.so",
	"libandroid.so",
	"libbinder_ndk.so",
	"libc.so",
	"libcamera2ndk.so",
	"libdl.so",
	"libEGL.so",
	"libGLESv1_CM.so",
	"libGLESv2.so",
	"libGLESv3.so",
	"libjnigraphics.so",
	"liblog.so",
	"libmediandk.so",
	"libm.so",
	"libnativewindow.so",
	"libneuralnetworks.so",
	"libOpenMAXAL.so",
	"libOpenSLES.so",
	"libRS.so",
	"libstdc++.so",
	"libsync.so",
	"libvulkan.so",
	"libz.so"
	};

	// System libraries that may exist in some types of builds.
	private final static String[] OPTIONAL_SYSTEM_LIBRARIES = {
	"libclang_rt.hwasan-aarch64-android.so"
	};

	// Libraries listed in public.libraries.android.txt, located in /apex/com.android.art/${LIB}
	private final static String[] PUBLIC_ART_LIBRARIES = {
	"libicui18n.so",
	"libicuuc.so",
	"libnativehelper.so",
	"libsigchain.so"
	};

	// The grey-list.
	private final static String[] PRIVATE_SYSTEM_LIBRARIES = {
	"libandroid_runtime.so",
	"libbinder.so",
	"libcrypto.so",
	"libcutils.so",
	"libexpat.so",
	"libgui.so",
	"libmedia.so",
	"libskia.so",
	"libssl.so",
	"libstagefright.so",
	"libsqlite.so",
	"libui.so",
	"libutils.so",
	"libvorbisidec.so",
	};

	private final static String WEBVIEW_PLAT_SUPPORT_LIB = "libwebviewchromium_plat_support.so";

	static enum Bitness { ALL, ONLY_32, ONLY_64 }

	private static List<String> readPublicLibrariesFile(File file) throws IOException {
	List<String> libs = new ArrayList<>();
	if (file.exists()) {
	try (BufferedReader br = new BufferedReader(new FileReader(file))) {
	String line;
	final boolean is64Bit = android.os.Process.is64Bit();
	while ((line = br.readLine()) != null) {
	line = line.trim();
	if (line.isEmpty() \|\| line.startsWith("#")) {
	continue;
	}
	String[] tokens = line.split(" ");
	if (tokens.length < 1 \|\| tokens.length > 3) {
	throw new RuntimeException("Malformed line: '" + line + "' in " + file);
	}
	String soname = tokens[0];
	Bitness bitness = Bitness.ALL;
	int i = tokens.length;
	while(--i >= 1) {
	if (tokens[i].equals("nopreload")) {
	continue;
	}
	else if (tokens[i].equals("32") \|\| tokens[i].equals("64")) {
	if (bitness != Bitness.ALL) {
	throw new RuntimeException("Malformed line: '" + line +
	"' in " + file + ". Bitness can be specified only once");
	}
	bitness = tokens[i].equals("32") ? Bitness.ONLY_32 : Bitness.ONLY_64;
	} else {
	throw new RuntimeException("Unrecognized token '" + tokens[i] +
	"' in " + file);
	}
	}
	if ((is64Bit && bitness == Bitness.ONLY_32) \|\|
	(!is64Bit && bitness == Bitness.ONLY_64)) {
	// skip unsupported bitness
	continue;
	}
	libs.add(soname);
	}
	}
	}
	return libs;
	}

	private static String readExtensionConfigFiles(String configDir, List<String> libs) throws IOException {
	File[] configFiles = new File(configDir).listFiles(
	new FilenameFilter() {
	public boolean accept(File dir, String name) {
	return EXTENSION_CONFIG_FILE_PATTERN.matcher(name).matches();
	}
	});
	if (configFiles == null) return null;

	for (File configFile: configFiles) {
	String fileName = configFile.toPath().getFileName().toString();
	Matcher configMatcher = EXTENSION_CONFIG_FILE_PATTERN.matcher(fileName);
	if (configMatcher.matches()) {
	String companyName = configMatcher.group(1);
	// a lib in public.libraries-acme.txt should be
	// libFoo.acme.so
	List<String> libNames = readPublicLibrariesFile(configFile);
	for (String lib : libNames) {
	if (lib.endsWith("." + companyName + ".so")) {
	libs.add(lib);
	} else {
	return "Library \"" + lib + "\" in " + configFile.toString()
	+ " must have company name " + companyName + " as suffix.";
	}
	}
	}
	}
	return null;
	}

	public static String runAccessibilityTest() throws IOException {
	List<String> systemLibs = new ArrayList<>();
	List<String> artApexLibs = new ArrayList<>();

	Collections.addAll(systemLibs, PUBLIC_SYSTEM_LIBRARIES);
	Collections.addAll(systemLibs, OPTIONAL_SYSTEM_LIBRARIES);
	// System path could contain public ART libraries on foreign arch. http://b/149852946
	if (isForeignArchitecture()) {
	Collections.addAll(systemLibs, PUBLIC_ART_LIBRARIES);
	}

	if (InstrumentationRegistry.getContext().getPackageManager().
	hasSystemFeature(PackageManager.FEATURE_WEBVIEW)) {
	systemLibs.add(WEBVIEW_PLAT_SUPPORT_LIB);
	}

	Collections.addAll(artApexLibs, PUBLIC_ART_LIBRARIES);

	// Check if /system/etc/public.libraries-company.txt and /product/etc/public.libraries
	// -company.txt files are well-formed. The libraries however are not loaded for test;
	// It is done in another test CtsUsesNativeLibraryTest because since Android S those libs
	// are not available unless they are explicited listed in the app manifest.

	List<String> oemLibs = new ArrayList<>();
	String oemLibsError = readExtensionConfigFiles(PUBLIC_CONFIG_DIR, oemLibs);
	if (oemLibsError != null) return oemLibsError;

	// PRODUCT libs that passed are also available
	List<String> productLibs = new ArrayList<>();
	String productLibsError = readExtensionConfigFiles(PRODUCT_CONFIG_DIR, productLibs);
	if (productLibsError != null) return productLibsError;

	// Make sure that the libs in grey-list are not exposed to apps. In fact, it
	// would be better for us to run this check against all system libraries which
	// are not NDK libs, but grey-list libs are enough for now since they have been
	// the most popular violators.
	Set<String> greyListLibs = new HashSet<>();
	Collections.addAll(greyListLibs, PRIVATE_SYSTEM_LIBRARIES);
	// Note: check for systemLibs isn't needed since we already checked
	// /system/etc/public.libraries.txt against NDK and
	// /system/etc/public.libraries-<company>.txt against lib<name>.<company>.so.
	List<String> vendorLibs = readPublicLibrariesFile(new File(VENDOR_CONFIG_FILE));
	for (String lib : vendorLibs) {
	if (greyListLibs.contains(lib)) {
	return "Internal library \"" + lib + "\" must not be available to apps.";
	}
	}

	return runAccessibilityTestImpl(systemLibs.toArray(new String[systemLibs.size()]),
	artApexLibs.toArray(new String[artApexLibs.size()]));
	}

	private static native String runAccessibilityTestImpl(String[] publicSystemLibs,
	String[] publicRuntimeLibs);

	private static void invokeIncrementGlobal(Class<?> clazz) throws Exception {
	clazz.getMethod("incrementGlobal").invoke(null);
	}
	private static int invokeGetGlobal(Class<?> clazz) throws Exception {
	return (Integer)clazz.getMethod("getGlobal").invoke(null);
	}

	private static ApplicationInfo getApplicationInfo(String packageName) {
	PackageManager pm = InstrumentationRegistry.getContext().getPackageManager();
	try {
	return pm.getApplicationInfo(packageName, 0);
	} catch (NameNotFoundException nnfe) {
	throw new RuntimeException(nnfe);
	}
	}

	private static String getSourcePath(String packageName) {
	String sourcePath = getApplicationInfo(packageName).sourceDir;
	if (sourcePath == null) {
	throw new IllegalStateException("No source path path found for " + packageName);
	}
	return sourcePath;
	}

	private static String getNativePath(String packageName) {
	String nativePath = getApplicationInfo(packageName).nativeLibraryDir;
	if (nativePath == null) {
	throw new IllegalStateException("No native path path found for " + packageName);
	}
	return nativePath;
	}

	private static boolean isAlreadyOpenedError(UnsatisfiedLinkError e, String libFilePath) {
	// If one of the public system libraries are already opened in the bootclassloader, consider
	// this try as success, because dlopen to the lib is successful.
	String baseName = new File(libFilePath).getName();
	return e.getMessage().contains("Shared library \"" + libFilePath +
	"\" already opened by ClassLoader") &&
	Arrays.asList(PUBLIC_SYSTEM_LIBRARIES).contains(baseName);
	}

	private static String loadWithSystemLoad(String libFilePath) {
	try {
	System.load(libFilePath);
	} catch (UnsatisfiedLinkError e) {
	// all other exceptions are just thrown
	if (!isAlreadyOpenedError(e, libFilePath)) {
	return "System.load() UnsatisfiedLinkError: " + e.getMessage();
	}
	}
	return "";
	}

	private static String loadWithSystemLoadLibrary(String libFileName) {
	// Drop 'lib' and '.so' from the base name
	String libName = libFileName.substring(3, libFileName.length()-3);
	try {
	System.loadLibrary(libName);
	} catch (UnsatisfiedLinkError e) {
	if (!isAlreadyOpenedError(e, libFileName)) {
	return "System.loadLibrary(\"" + libName + "\") UnsatisfiedLinkError: " +
	e.getMessage();
	}
	}
	return "";
	}

	// Verify the behaviour of native library loading in class loaders.
	// In this test:
	// - libjninamespacea1, libjninamespacea2 and libjninamespaceb depend on libjnicommon
	// - loaderA will load ClassNamespaceA1 (loading libjninamespacea1)
	// - loaderA will load ClassNamespaceA2 (loading libjninamespacea2)
	// - loaderB will load ClassNamespaceB (loading libjninamespaceb)
	// - incrementGlobal/getGlobal operate on a static global from libjnicommon
	// and each class should get its own view on it.
	//
	// This is a test case for 2 different scenarios:
	// - loading native libraries in different class loaders
	// - loading native libraries in the same class loader
	// Ideally we would have 2 different tests but JNI doesn't allow loading the same library in
	// different class loaders. So to keep the number of native libraries manageable we just
	// re-use the same class loaders for the two tests.
	public static String runClassLoaderNamespaces() throws Exception {
	// Test for different class loaders.
	// Verify that common dependencies get a separate copy in each class loader.
	// libjnicommon should be loaded twice:
	// in the namespace for loaderA and the one for loaderB.
	String apkPath = getSourcePath("android.jni.cts");
	String nativePath = getNativePath("android.jni.cts");
	PathClassLoader loaderA = new PathClassLoader(
	apkPath, nativePath, ClassLoader.getSystemClassLoader());
	Class<?> testA1Class = loaderA.loadClass("android.jni.cts.ClassNamespaceA1");
	PathClassLoader loaderB = new PathClassLoader(
	apkPath, nativePath, ClassLoader.getSystemClassLoader());
	Class<?> testBClass = loaderB.loadClass("android.jni.cts.ClassNamespaceB");

	int globalA1 = invokeGetGlobal(testA1Class);
	int globalB = invokeGetGlobal(testBClass);
	if (globalA1 != 0 \|\| globalB != 0) {
	return "Expected globals to be 0/0: globalA1=" + globalA1 + " globalB=" + globalB;
	}

	invokeIncrementGlobal(testA1Class);
	globalA1 = invokeGetGlobal(testA1Class);
	globalB = invokeGetGlobal(testBClass);
	if (globalA1 != 1 \|\| globalB != 0) {
	return "Expected globals to be 1/0: globalA1=" + globalA1 + " globalB=" + globalB;
	}

	invokeIncrementGlobal(testBClass);
	globalA1 = invokeGetGlobal(testA1Class);
	globalB = invokeGetGlobal(testBClass);
	if (globalA1 != 1 \|\| globalB != 1) {
	return "Expected globals to be 1/1: globalA1=" + globalA1 + " globalB=" + globalB;
	}

	// Test for the same class loaders.
	// Verify that if we load ClassNamespaceA2 into loaderA we get the same view on the
	// globals.
	Class<?> testA2Class = loaderA.loadClass("android.jni.cts.ClassNamespaceA2");

	int globalA2 = invokeGetGlobal(testA2Class);
	if (globalA1 != 1 \|\| globalA2 !=1) {
	return "Expected globals to be 1/1: globalA1=" + globalA1 + " globalA2=" + globalA2;
	}

	invokeIncrementGlobal(testA1Class);
	globalA1 = invokeGetGlobal(testA1Class);
	globalA2 = invokeGetGlobal(testA2Class);
	if (globalA1 != 2 \|\| globalA2 != 2) {
	return "Expected globals to be 2/2: globalA1=" + globalA1 + " globalA2=" + globalA2;
	}

	invokeIncrementGlobal(testA2Class);
	globalA1 = invokeGetGlobal(testA1Class);
	globalA2 = invokeGetGlobal(testA2Class);
	if (globalA1 != 3 \|\| globalA2 != 3) {
	return "Expected globals to be 2/2: globalA1=" + globalA1 + " globalA2=" + globalA2;
	}
	// On success we return null.
	return null;
	}

	public static String runDlopenPublicLibraries() {
	String error = null;
	List<String> publicLibs = new ArrayList<>();
	Collections.addAll(publicLibs, PUBLIC_SYSTEM_LIBRARIES);
	Collections.addAll(publicLibs, PUBLIC_ART_LIBRARIES);
	for (String lib : publicLibs) {
	String result = LinkerNamespacesHelper.tryDlopen(lib);
	if (result != null) {
	if (error == null) {
	error = "";
	}
	error += result + "\n";
	}
	}
	return error;
	}

	public static native String tryDlopen(String lib);

	private static boolean isForeignArchitecture() {
	int libAbi = getLibAbi();
	String cpuAbi = android.os.SystemProperties.get("ro.product.cpu.abi");
	if ((libAbi == 1 \|\| libAbi == 2) && !cpuAbi.startsWith("arm")) {
	return true;
	} else if ((libAbi == 3 \|\| libAbi == 4) && !cpuAbi.startsWith("x86")) {
	return true;
	}
	return false;
	}

	/**
	* @return ABI type of the JNI library. 1: ARM64, 2:ARM, 3: x86_64, 4: x86, 0: others
	*/
	private static native int getLibAbi();
	}

	class ClassNamespaceA1 {
	static {
	System.loadLibrary("jninamespacea1");
	}

	public static native void incrementGlobal();
	public static native int getGlobal();
	}

	class ClassNamespaceA2 {
	static {
	System.loadLibrary("jninamespacea2");
	}

	public static native void incrementGlobal();
	public static native int getGlobal();
	}

	class ClassNamespaceB {
	static {
	System.loadLibrary("jninamespaceb");
	}

	public static native void incrementGlobal();
	public static native int getGlobal();
	}