/*
* Minecraft Forge
* Copyright (c) 2016.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation version 2.1
* of the License.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package net.minecraftforge.fml.common.asm.transformers;
import org.objectweb.asm.*;
import net.minecraft.launchwrapper.IClassTransformer;
import net.minecraftforge.fml.relauncher.FMLRelaunchLog;
import net.minecraftforge.fml.relauncher.FMLSecurityManager.ExitTrappedException;
public class TerminalTransformer implements IClassTransformer
{
@Override
public byte[] transform(String name, String transformedName, byte[] basicClass)
{
if (basicClass == null) return null;
ClassReader reader = new ClassReader(basicClass);
ClassWriter writer = new ClassWriter(ClassWriter.COMPUTE_MAXS);
ClassVisitor visitor = writer;
visitor = new ExitVisitor(visitor);
reader.accept(visitor, 0);
return writer.toByteArray();
}
public static class ExitVisitor extends ClassVisitor
{
private String clsName = null;
private static final String callbackOwner = org.objectweb.asm.Type.getInternalName(ExitVisitor.class);
private ExitVisitor(ClassVisitor cv)
{
super(Opcodes.ASM5, cv);
}
@Override
public void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
{
super.visit(version, access, name, signature, superName, interfaces);
this.clsName = name;
}
@Override
public MethodVisitor visitMethod(int mAccess, final String mName, final String mDesc, String mSignature, String[] mExceptions)
{
final boolean warn = !(clsName.equals("net/minecraft/client/Minecraft") ||
clsName.equals("net/minecraft/server/dedicated/DedicatedServer") ||
clsName.equals("net/minecraft/server/dedicated/ServerHangWatchdog") ||
clsName.equals("net/minecraft/server/dedicated/ServerHangWatchdog$1") ||
clsName.equals("net/minecraftforge/fml/common/FMLCommonHandler") ||
clsName.startsWith("com/jcraft/jogg/") ||
clsName.startsWith("scala/sys/") ||
clsName.startsWith("net/minecraft/server/gui/MinecraftServerGui") ||
clsName.startsWith("com/sun/jna/")
);
return new MethodVisitor(Opcodes.ASM5, super.visitMethod(mAccess, mName, mDesc, mSignature, mExceptions))
{
@Override
public void visitMethodInsn(int opcode, String owner, String name, String desc, boolean isIntf)
{
if (opcode == Opcodes.INVOKESTATIC && owner.equals("java/lang/System") && name.equals("exit") && desc.equals("(I)V"))
{
if (warn)
{
FMLRelaunchLog.warning("=============================================================");
FMLRelaunchLog.warning("MOD HAS DIRECT REFERENCE System.exit() THIS IS NOT ALLOWED REROUTING TO FML!");
FMLRelaunchLog.warning("Offender: %s.%s%s", ExitVisitor.this.clsName, mName, mDesc);
FMLRelaunchLog.warning("Use FMLCommonHandler.exitJava instead");
FMLRelaunchLog.warning("=============================================================");
}
owner = ExitVisitor.callbackOwner;
name = "systemExitCalled";
}
else if (opcode == Opcodes.INVOKEVIRTUAL && owner.equals("java/lang/Runtime") && name.equals("exit") && desc.equals("(I)V"))
{
if (warn)
{
FMLRelaunchLog.warning("=============================================================");
FMLRelaunchLog.warning("MOD HAS DIRECT REFERENCE Runtime.exit() THIS IS NOT ALLOWED REROUTING TO FML!");
FMLRelaunchLog.warning("Offender: %s.%s%s", ExitVisitor.this.clsName, mName, mDesc);
FMLRelaunchLog.warning("Use FMLCommonHandler.exitJava instead");
FMLRelaunchLog.warning("=============================================================");
}
opcode = Opcodes.INVOKESTATIC;
owner = ExitVisitor.callbackOwner;
name = "runtimeExitCalled";
desc = "(Ljava/lang/Runtime;I)V";
}
else if (opcode == Opcodes.INVOKEVIRTUAL && owner.equals("java/lang/Runtime") && name.equals("halt") && desc.equals("(I)V"))
{
if (warn)
{
FMLRelaunchLog.warning("=============================================================");
FMLRelaunchLog.warning("MOD HAS DIRECT REFERENCE Runtime.halt() THIS IS NOT ALLOWED REROUTING TO FML!");
FMLRelaunchLog.warning("Offendor: %s.%s%s", ExitVisitor.this.clsName, mName, mDesc);
FMLRelaunchLog.warning("Use FMLCommonHandler.exitJava instead");
FMLRelaunchLog.warning("=============================================================");
}
opcode = Opcodes.INVOKESTATIC;
owner = ExitVisitor.callbackOwner;
name = "runtimeHaltCalled";
desc = "(Ljava/lang/Runtime;I)V";
}
super.visitMethodInsn(opcode, owner, name, desc, isIntf);
}
};
}
// Intercept System.exit, and check if the caller is allowed to use it, if not wrap it in a ExitTrappedException
public static void systemExitCalled(int status)
{
ExitVisitor.checkAccess();
System.exit(status);
}
// Intercept Runtime.getRuntime().exit, and check if the caller is allowed to use it, if not wrap it in a ExitTrappedException
public static void runtimeExitCalled(Runtime runtime, int status)
{
ExitVisitor.checkAccess();
runtime.exit(status);
}
// Intercept Runtime.getRuntime().halt, and check if the caller is allowed to use it, if not wrap it in a ExitTrappedException
public static void runtimeHaltCalled(Runtime runtime, int status)
{
ExitVisitor.checkAccess();
runtime.halt(status);
}
private static void checkAccess()
{
StackTraceElement[] cause = Thread.currentThread().getStackTrace();
String callingClass = cause.length > 2 ? cause[3].getClassName() : "none";
String callingParent = cause.length > 3 ? cause[4].getClassName() : "none";
// FML is allowed to call system exit and the Minecraft applet (from the quit button), and the dedicated server (from itself)
boolean allowed = false;
allowed |= callingClass.startsWith("net.minecraftforge.fml.");
allowed |= callingClass.equals("net.minecraft.client.Minecraft") && callingParent.equals("net.minecraft.client.Minecraft");
allowed |= callingClass.equals("net.minecraft.server.gui.MinecraftServerGui$1") && callingParent.equals("java.awt.AWTEventMulticaster");
allowed |= callingClass.equals("net.minecraft.server.dedicated.DedicatedServer") && callingParent.equals("net.minecraft.server.MinecraftServer");
allowed |= callingClass.equals("net.minecraft.server.dedicated.ServerHangWatchdog");
allowed |= callingClass.equals("net.minecraft.server.dedicated.ServerHangWatchdog$1");
if (!allowed)
{
throw new ExitTrappedException();
}
}
}
}