/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.util.internal;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.chmv8.ConcurrentHashMapV8;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Utility that detects various properties specific to the current runtime
* environment, such as Java version and the availability of the
* {@code sun.misc.Unsafe} object.
* <p>
* You can disable the use of {@code sun.misc.Unsafe} if you specify
* the system property <strong>io.netty.noUnsafe</strong>.
*/
public final class PlatformDependent {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(PlatformDependent.class);
private static final Pattern MAX_DIRECT_MEMORY_SIZE_ARG_PATTERN = Pattern.compile(
"\\s*-XX:MaxDirectMemorySize\\s*=\\s*([0-9]+)\\s*([kKmMgG]?)\\s*$");
private static final boolean IS_ANDROID = isAndroid0();
private static final boolean IS_WINDOWS = isWindows0();
private static final boolean IS_ROOT = isRoot0();
private static final int JAVA_VERSION = javaVersion0();
private static final boolean CAN_ENABLE_TCP_NODELAY_BY_DEFAULT = !isAndroid();
private static final boolean HAS_UNSAFE = hasUnsafe0();
private static final boolean CAN_USE_CHM_V8 = HAS_UNSAFE && JAVA_VERSION < 8;
private static final boolean DIRECT_BUFFER_PREFERRED =
HAS_UNSAFE && !SystemPropertyUtil.getBoolean("io.netty.noPreferDirect", false);
private static final long MAX_DIRECT_MEMORY = maxDirectMemory0();
private static final long ARRAY_BASE_OFFSET = arrayBaseOffset0();
private static final boolean HAS_JAVASSIST = hasJavassist0();
static {
if (logger.isDebugEnabled()) {
logger.debug("-Dio.netty.noPreferDirect: {}", !DIRECT_BUFFER_PREFERRED);
}
if (!hasUnsafe()) {
logger.info(
"Your platform does not provide complete low-level API for accessing direct buffers reliably. " +
"Unless explicitly requested, heap buffer will always be preferred to avoid potential system " +
"unstability.");
}
}
/**
* Returns {@code true} if and only if the current platform is Android
*/
public static boolean isAndroid() {
return IS_ANDROID;
}
/**
* Return {@code true} if the JVM is running on Windows
*/
public static boolean isWindows() {
return IS_WINDOWS;
}
/**
* Return {@code true} if the current user is root. Note that this method returns
* {@code false} if on Windows.
*/
public static boolean isRoot() {
return IS_ROOT;
}
/**
* Return the version of Java under which this library is used.
*/
public static int javaVersion() {
return JAVA_VERSION;
}
/**
* Returns {@code true} if and only if it is fine to enable TCP_NODELAY socket option by default.
*/
public static boolean canEnableTcpNoDelayByDefault() {
return CAN_ENABLE_TCP_NODELAY_BY_DEFAULT;
}
/**
* Return {@code true} if {@code sun.misc.Unsafe} was found on the classpath and can be used for acclerated
* direct memory access.
*/
public static boolean hasUnsafe() {
return HAS_UNSAFE;
}
/**
* Returns {@code true} if the platform has reliable low-level direct buffer access API and a user specified
* {@code -Dio.netty.preferDirect} option.
*/
public static boolean directBufferPreferred() {
return DIRECT_BUFFER_PREFERRED;
}
/**
* Returns the maximum memory reserved for direct buffer allocation.
*/
public static long maxDirectMemory() {
return MAX_DIRECT_MEMORY;
}
/**
* Returns {@code true} if and only if Javassist is available.
*/
public static boolean hasJavassist() {
return HAS_JAVASSIST;
}
/**
* Raises an exception bypassing compiler checks for checked exceptions.
*/
public static void throwException(Throwable t) {
if (hasUnsafe()) {
PlatformDependent0.throwException(t);
} else {
PlatformDependent.<RuntimeException>throwException0(t);
}
}
@SuppressWarnings("unchecked")
private static <E extends Throwable> void throwException0(Throwable t) throws E {
throw (E) t;
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
public static <K, V> ConcurrentMap<K, V> newConcurrentHashMap() {
if (CAN_USE_CHM_V8) {
return new ConcurrentHashMapV8<K, V>();
} else {
return new ConcurrentHashMap<K, V>();
}
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
public static <K, V> ConcurrentMap<K, V> newConcurrentHashMap(int initialCapacity) {
if (CAN_USE_CHM_V8) {
return new ConcurrentHashMapV8<K, V>(initialCapacity);
} else {
return new ConcurrentHashMap<K, V>(initialCapacity);
}
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
public static <K, V> ConcurrentMap<K, V> newConcurrentHashMap(int initialCapacity, float loadFactor) {
if (CAN_USE_CHM_V8) {
return new ConcurrentHashMapV8<K, V>(initialCapacity, loadFactor);
} else {
return new ConcurrentHashMap<K, V>(initialCapacity, loadFactor);
}
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
public static <K, V> ConcurrentMap<K, V> newConcurrentHashMap(
int initialCapacity, float loadFactor, int concurrencyLevel) {
if (CAN_USE_CHM_V8) {
return new ConcurrentHashMapV8<K, V>(initialCapacity, loadFactor, concurrencyLevel);
} else {
return new ConcurrentHashMap<K, V>(initialCapacity, loadFactor, concurrencyLevel);
}
}
/**
* Creates a new fastest {@link ConcurrentMap} implementaion for the current platform.
*/
public static <K, V> ConcurrentMap<K, V> newConcurrentHashMap(Map<? extends K, ? extends V> map) {
if (CAN_USE_CHM_V8) {
return new ConcurrentHashMapV8<K, V>(map);
} else {
return new ConcurrentHashMap<K, V>(map);
}
}
/**
* Try to deallocate the specified direct {@link ByteBuffer}. Please note this method does nothing if
* the current platform does not support this operation or the specified buffer is not a direct buffer.
*/
public static void freeDirectBuffer(ByteBuffer buffer) {
if (buffer.isDirect()) {
if (hasUnsafe()) {
PlatformDependent0.freeDirectBufferUnsafe(buffer);
} else {
PlatformDependent0.freeDirectBuffer(buffer);
}
}
}
public static long directBufferAddress(ByteBuffer buffer) {
return PlatformDependent0.directBufferAddress(buffer);
}
public static Object getObject(Object object, long fieldOffset) {
return PlatformDependent0.getObject(object, fieldOffset);
}
public static int getInt(Object object, long fieldOffset) {
return PlatformDependent0.getInt(object, fieldOffset);
}
public static long objectFieldOffset(Field field) {
return PlatformDependent0.objectFieldOffset(field);
}
public static byte getByte(long address) {
return PlatformDependent0.getByte(address);
}
public static short getShort(long address) {
return PlatformDependent0.getShort(address);
}
public static int getInt(long address) {
return PlatformDependent0.getInt(address);
}
public static long getLong(long address) {
return PlatformDependent0.getLong(address);
}
public static void putByte(long address, byte value) {
PlatformDependent0.putByte(address, value);
}
public static void putShort(long address, short value) {
PlatformDependent0.putShort(address, value);
}
public static void putInt(long address, int value) {
PlatformDependent0.putInt(address, value);
}
public static void putLong(long address, long value) {
PlatformDependent0.putLong(address, value);
}
public static void copyMemory(long srcAddr, long dstAddr, long length) {
PlatformDependent0.copyMemory(srcAddr, dstAddr, length);
}
public static void copyMemory(byte[] src, int srcIndex, long dstAddr, long length) {
PlatformDependent0.copyMemory(src, ARRAY_BASE_OFFSET + srcIndex, null, dstAddr, length);
}
public static void copyMemory(long srcAddr, byte[] dst, int dstIndex, long length) {
PlatformDependent0.copyMemory(null, srcAddr, dst, ARRAY_BASE_OFFSET + dstIndex, length);
}
private static boolean isAndroid0() {
boolean android;
try {
Class.forName("android.app.Application", false, ClassLoader.getSystemClassLoader());
android = true;
} catch (Exception e) {
android = false;
}
if (android) {
logger.debug("Platform: Android");
}
return android;
}
private static boolean isWindows0() {
boolean windows = SystemPropertyUtil.get("os.name", "").toLowerCase(Locale.US).contains("win");
if (windows) {
logger.debug("Platform: Windows");
}
return windows;
}
private static boolean isRoot0() {
if (isWindows()) {
return false;
}
String[] ID_COMMANDS = { "/usr/bin/id", "/bin/id", "id", "/usr/xpg4/bin/id"};
Pattern UID_PATTERN = Pattern.compile("^(?:0|[1-9][0-9]*)$");
for (String idCmd: ID_COMMANDS) {
Process p = null;
BufferedReader in = null;
String uid = null;
try {
p = Runtime.getRuntime().exec(new String[] { idCmd, "-u" });
in = new BufferedReader(new InputStreamReader(p.getInputStream(), CharsetUtil.US_ASCII));
uid = in.readLine();
in.close();
for (;;) {
try {
int exitCode = p.waitFor();
if (exitCode != 0) {
uid = null;
}
break;
} catch (InterruptedException e) {
// Ignore
}
}
} catch (Exception e) {
uid = null;
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
// Ignore
}
}
if (p != null) {
try {
p.destroy();
} catch (Exception e) {
// Android sometimes triggers an ErrnoException.
}
}
}
if (uid != null && UID_PATTERN.matcher(uid).matches()) {
logger.debug("UID: {}", uid);
return "0".equals(uid);
}
}
logger.debug("Could not determine the current UID using /usr/bin/id; attempting to bind at privileged ports.");
Pattern PERMISSION_DENIED = Pattern.compile(".*(?:denied|not.*permitted).*");
for (int i = 1023; i > 0; i --) {
ServerSocket ss = null;
try {
ss = new ServerSocket();
ss.setReuseAddress(true);
ss.bind(new InetSocketAddress(i));
if (logger.isDebugEnabled()) {
logger.debug("UID: 0 (succeded to bind at port {})", i);
}
return true;
} catch (Exception e) {
// Failed to bind.
// Check the error message so that we don't always need to bind 1023 times.
String message = e.getMessage();
if (message == null) {
message = "";
}
message = message.toLowerCase();
if (PERMISSION_DENIED.matcher(message).matches()) {
break;
}
} finally {
if (ss != null) {
try {
ss.close();
} catch (Exception e) {
// Ignore.
}
}
}
}
logger.debug("UID: non-root (failed to bind at any privileged ports)");
return false;
}
@SuppressWarnings("LoopStatementThatDoesntLoop")
private static int javaVersion0() {
int javaVersion;
// Not really a loop
for (;;) {
// Android
if (isAndroid()) {
javaVersion = 6;
break;
}
try {
Class.forName("java.time.Clock", false, Object.class.getClassLoader());
javaVersion = 8;
break;
} catch (Exception e) {
// Ignore
}
try {
Class.forName("java.util.concurrent.LinkedTransferQueue", false, BlockingQueue.class.getClassLoader());
javaVersion = 7;
break;
} catch (Exception e) {
// Ignore
}
javaVersion = 6;
break;
}
if (logger.isDebugEnabled()) {
logger.debug("Java version: {}", javaVersion);
}
return javaVersion;
}
private static boolean hasUnsafe0() {
boolean noUnsafe = SystemPropertyUtil.getBoolean("io.netty.noUnsafe", false);
logger.debug("-Dio.netty.noUnsafe: {}", noUnsafe);
if (isAndroid()) {
logger.debug("sun.misc.Unsafe: unavailable (Android)");
return false;
}
if (noUnsafe) {
logger.debug("sun.misc.Unsafe: unavailable (io.netty.noUnsafe)");
return false;
}
// Legacy properties
boolean tryUnsafe;
if (SystemPropertyUtil.contains("io.netty.tryUnsafe")) {
tryUnsafe = SystemPropertyUtil.getBoolean("io.netty.tryUnsafe", true);
} else {
tryUnsafe = SystemPropertyUtil.getBoolean("org.jboss.netty.tryUnsafe", true);
}
if (!tryUnsafe) {
logger.debug("sun.misc.Unsafe: unavailable (io.netty.tryUnsafe/org.jboss.netty.tryUnsafe)");
return false;
}
try {
boolean hasUnsafe = PlatformDependent0.hasUnsafe();
logger.debug("sun.misc.Unsafe: {}", hasUnsafe ? "available" : "unavailable");
return hasUnsafe;
} catch (Throwable t) {
return false;
}
}
private static long arrayBaseOffset0() {
if (!hasUnsafe()) {
return -1;
}
return PlatformDependent0.arrayBaseOffset();
}
private static long maxDirectMemory0() {
long maxDirectMemory = 0;
try {
// Try to get from sun.misc.VM.maxDirectMemory() which should be most accurate.
Class<?> vmClass = Class.forName("sun.misc.VM", true, ClassLoader.getSystemClassLoader());
Method m = vmClass.getDeclaredMethod("maxDirectMemory");
maxDirectMemory = ((Number) m.invoke(null)).longValue();
} catch (Throwable t) {
// Ignore
}
if (maxDirectMemory > 0) {
return maxDirectMemory;
}
try {
// Now try to get the JVM option (-XX:MaxDirectMemorySize) and parse it.
// Note that we are using reflection because Android doesn't have these classes.
Class<?> mgmtFactoryClass = Class.forName(
"java.lang.management.ManagementFactory", true, ClassLoader.getSystemClassLoader());
Class<?> runtimeClass = Class.forName(
"java.lang.management.RuntimeMXBean", true, ClassLoader.getSystemClassLoader());
Object runtime = mgmtFactoryClass.getDeclaredMethod("getRuntimeMXBean").invoke(null);
@SuppressWarnings("unchecked")
List<String> vmArgs = (List<String>) runtimeClass.getDeclaredMethod("getInputArguments").invoke(runtime);
for (int i = vmArgs.size() - 1; i >= 0; i --) {
Matcher m = MAX_DIRECT_MEMORY_SIZE_ARG_PATTERN.matcher(vmArgs.get(i));
if (!m.matches()) {
continue;
}
maxDirectMemory = Long.parseLong(m.group(1));
switch (m.group(2).charAt(0)) {
case 'k': case 'K':
maxDirectMemory *= 1024;
break;
case 'm': case 'M':
maxDirectMemory *= 1024 * 1024;
break;
case 'g': case 'G':
maxDirectMemory *= 1024 * 1024 * 1024;
break;
}
break;
}
} catch (Throwable t) {
// Ignore
}
if (maxDirectMemory <= 0) {
maxDirectMemory = Runtime.getRuntime().maxMemory();
logger.debug("maxDirectMemory: {} bytes (maybe)", maxDirectMemory);
} else {
logger.debug("maxDirectMemory: {} bytes", maxDirectMemory);
}
return maxDirectMemory;
}
private static boolean hasJavassist0() {
boolean noJavassist = SystemPropertyUtil.getBoolean("io.netty.noJavassist", false);
logger.debug("-Dio.netty.noJavassist: {}", noJavassist);
if (noJavassist) {
logger.debug("Javassist: unavailable (io.netty.noJavassist)");
return false;
}
try {
JavassistTypeParameterMatcherGenerator.generate(Object.class, PlatformDependent.class.getClassLoader());
logger.debug("Javassist: available");
return true;
} catch (Throwable t) {
logger.debug("Javassist: unavailable");
logger.debug(
"You don't have Javassist in your class path or you don't have enough permission " +
"to load dynamically generated classes. Please check the configuration for better performance.");
return false;
}
}
private PlatformDependent() {
// only static method supported
}
}