/*
* Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.lang;
import java.io.*;
import java.lang.reflect.Executable;
import java.lang.annotation.Annotation;
import java.security.AccessControlContext;
import java.util.Properties;
import java.util.PropertyPermission;
import java.util.StringTokenizer;
import java.util.Map;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.nio.channels.Channel;
import java.nio.channels.spi.SelectorProvider;
import com.alibaba.rcm.internal.AbstractResourceContainer;
import com.alibaba.tenant.TenantContainer;
import com.alibaba.tenant.TenantGlobals;
import com.alibaba.wisp.engine.WispEngine;
import com.alibaba.wisp.engine.WispTask;
import sun.misc.VM;
import sun.nio.ch.Interruptible;
import sun.reflect.CallerSensitive;
import sun.reflect.Reflection;
import sun.security.util.SecurityConstants;
import sun.reflect.annotation.AnnotationType;
import jdk.internal.util.StaticProperty;
/**
* The System class contains several useful class fields
* and methods. It cannot be instantiated.
*
*
Among the facilities provided by the System class
* are standard input, standard output, and error output streams;
* access to externally defined properties and environment
* variables; a means of loading files and libraries; and a utility
* method for quickly copying a portion of an array.
*
* @author unascribed
* @since JDK1.0
*/
public final class System {
/* register the natives via the static initializer.
*
* VM will invoke the initializeSystemClass method to complete
* the initialization for this class separated from clinit.
* Note that to use properties set by the VM, see the constraints
* described in the initializeSystemClass method.
*/
private static native void registerNatives();
static {
registerNatives();
}
/** Don't let anyone instantiate this class */
private System() {
}
/**
* The "standard" input stream. This stream is already
* open and ready to supply input data. Typically this stream
* corresponds to keyboard input or another input source specified by
* the host environment or user.
*/
public final static InputStream in = null;
/**
* The "standard" output stream. This stream is already
* open and ready to accept output data. Typically this stream
* corresponds to display output or another output destination
* specified by the host environment or user.
*
* For simple stand-alone Java applications, a typical way to write
* a line of output data is:
*
* System.out.println(data)
*
*
* See the println methods in class PrintStream.
*
* @see java.io.PrintStream#println()
* @see java.io.PrintStream#println(boolean)
* @see java.io.PrintStream#println(char)
* @see java.io.PrintStream#println(char[])
* @see java.io.PrintStream#println(double)
* @see java.io.PrintStream#println(float)
* @see java.io.PrintStream#println(int)
* @see java.io.PrintStream#println(long)
* @see java.io.PrintStream#println(java.lang.Object)
* @see java.io.PrintStream#println(java.lang.String)
*/
public final static PrintStream out = null;
/**
* The "standard" error output stream. This stream is already
* open and ready to accept output data.
*
* Typically this stream corresponds to display output or another
* output destination specified by the host environment or user. By
* convention, this output stream is used to display error messages
* or other information that should come to the immediate attention
* of a user even if the principal output stream, the value of the
* variable out, has been redirected to a file or other
* destination that is typically not continuously monitored.
*/
public final static PrintStream err = null;
/* The security manager for the system.
*/
private static volatile SecurityManager security = null;
/**
* Reassigns the "standard" input stream.
*
*
First, if there is a security manager, its checkPermission
* method is called with a RuntimePermission("setIO") permission
* to see if it's ok to reassign the "standard" input stream.
*
*
* @param in the new standard input stream.
*
* @throws SecurityException
* if a security manager exists and its
* checkPermission method doesn't allow
* reassigning of the standard input stream.
*
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*
* @since JDK1.1
*/
public static void setIn(InputStream in) {
checkIO();
setIn0(in);
}
/**
* Reassigns the "standard" output stream.
*
*
First, if there is a security manager, its checkPermission
* method is called with a RuntimePermission("setIO") permission
* to see if it's ok to reassign the "standard" output stream.
*
* @param out the new standard output stream
*
* @throws SecurityException
* if a security manager exists and its
* checkPermission method doesn't allow
* reassigning of the standard output stream.
*
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*
* @since JDK1.1
*/
public static void setOut(PrintStream out) {
checkIO();
setOut0(out);
}
/**
* Reassigns the "standard" error output stream.
*
*
First, if there is a security manager, its checkPermission
* method is called with a RuntimePermission("setIO") permission
* to see if it's ok to reassign the "standard" error output stream.
*
* @param err the new standard error output stream.
*
* @throws SecurityException
* if a security manager exists and its
* checkPermission method doesn't allow
* reassigning of the standard error output stream.
*
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*
* @since JDK1.1
*/
public static void setErr(PrintStream err) {
checkIO();
setErr0(err);
}
private static volatile Console cons = null;
/**
* Returns the unique {@link java.io.Console Console} object associated
* with the current Java virtual machine, if any.
*
* @return The system console, if any, otherwise null.
*
* @since 1.6
*/
public static Console console() {
if (cons == null) {
synchronized (System.class) {
cons = sun.misc.SharedSecrets.getJavaIOAccess().console();
}
}
return cons;
}
/**
* Returns the channel inherited from the entity that created this
* Java virtual machine.
*
*
This method returns the channel obtained by invoking the
* {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
* inheritedChannel} method of the system-wide default
* {@link java.nio.channels.spi.SelectorProvider} object.
*
*
In addition to the network-oriented channels described in
* {@link java.nio.channels.spi.SelectorProvider#inheritedChannel
* inheritedChannel}, this method may return other kinds of
* channels in the future.
*
* @return The inherited channel, if any, otherwise null.
*
* @throws IOException
* If an I/O error occurs
*
* @throws SecurityException
* If a security manager is present and it does not
* permit access to the channel.
*
* @since 1.5
*/
public static Channel inheritedChannel() throws IOException {
return SelectorProvider.provider().inheritedChannel();
}
private static void checkIO() {
SecurityManager sm = getSecurityManager();
if (sm != null) {
sm.checkPermission(new RuntimePermission("setIO"));
}
}
private static native void setIn0(InputStream in);
private static native void setOut0(PrintStream out);
private static native void setErr0(PrintStream err);
/**
* Sets the System security.
*
*
If there is a security manager already installed, this method first
* calls the security manager's checkPermission method
* with a RuntimePermission("setSecurityManager")
* permission to ensure it's ok to replace the existing
* security manager.
* This may result in throwing a SecurityException.
*
*
Otherwise, the argument is established as the current
* security manager. If the argument is null and no
* security manager has been established, then no action is taken and
* the method simply returns.
*
* @param s the security manager.
* @exception SecurityException if the security manager has already
* been set and its checkPermission method
* doesn't allow it to be replaced.
* @see #getSecurityManager
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*/
public static
void setSecurityManager(final SecurityManager s) {
try {
s.checkPackageAccess("java.lang");
} catch (Exception e) {
// no-op
}
setSecurityManager0(s);
}
private static synchronized
void setSecurityManager0(final SecurityManager s) {
SecurityManager sm = getSecurityManager();
if (sm != null) {
// ask the currently installed security manager if we
// can replace it.
sm.checkPermission(new RuntimePermission
("setSecurityManager"));
}
if ((s != null) && (s.getClass().getClassLoader() != null)) {
// New security manager class is not on bootstrap classpath.
// Cause policy to get initialized before we install the new
// security manager, in order to prevent infinite loops when
// trying to initialize the policy (which usually involves
// accessing some security and/or system properties, which in turn
// calls the installed security manager's checkPermission method
// which will loop infinitely if there is a non-system class
// (in this case: the new security manager class) on the stack).
AccessController.doPrivileged(new PrivilegedAction