scouter.agent.asm.HttpServiceASM.java Source code

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Here is the source code for scouter.agent.asm.HttpServiceASM.java

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/*
 *  Copyright 2015 the original author or authors. 
 *  @https://github.com/scouter-project/scouter
 *
 *  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 scouter.agent.asm;

import org.objectweb.asm.*;
import org.objectweb.asm.commons.LocalVariablesSorter;
import scouter.agent.ClassDesc;
import scouter.agent.Configure;
import scouter.agent.Logger;
import scouter.agent.trace.TraceMain;

import java.util.HashSet;

public class HttpServiceASM implements IASM, Opcodes {
    public HashSet<String> servlets = new HashSet<String>();

    public HttpServiceASM() {
        servlets.add("javax/servlet/http/HttpServlet");
        servlets.add("weblogic/servlet/jsp/JspBase");
    }

    public ClassVisitor transform(ClassVisitor cv, String className, ClassDesc classDesc) {
        if (Configure.getInstance()._hook_serivce_enabled == false) {
            return cv;
        }
        if (servlets.contains(className)) {
            return new HttpServiceCV(cv, className);
        }
        for (int i = 0; classDesc.interfaces != null && i < classDesc.interfaces.length; i++) {
            if ("javax/servlet/Filter".equals(classDesc.interfaces[i])) {
                return new HttpServiceCV(cv, className);
            }
        }
        return cv;
    }
}

class HttpServiceCV extends ClassVisitor implements Opcodes {
    private static String TARGET_SERVICE = "service";
    private static String TARGET_DOFILTER = "doFilter";
    private static String TARGET_SIGNATURE = "(Ljavax/servlet/ServletRequest;Ljavax/servlet/ServletResponse;";
    private String className;

    public HttpServiceCV(ClassVisitor cv, String className) {
        super(ASM7, cv);
        this.className = className;
    }

    @Override
    public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
        MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
        if (mv == null) {
            return mv;
        }
        if (desc.startsWith(TARGET_SIGNATURE)) {
            if (TARGET_SERVICE.equals(name)) {
                Logger.println("A103", "HTTP " + className);
                return new HttpServiceMV(access, desc, mv, true);
            } else if (TARGET_DOFILTER.equals(name)) {
                Logger.println("A104", "FILTER " + className);
                return new HttpServiceMV(access, desc, mv, false);
            }
        }
        return mv;
    }
}

// ///////////////////////////////////////////////////////////////////////////
class HttpServiceMV extends LocalVariablesSorter implements Opcodes {
    private static final String TRACEMAIN = TraceMain.class.getName().replace('.', '/');
    private final static String START_SERVICE = "startHttpService";
    private final static String START_FILTER = "startHttpFilter";
    private static final String START_SIGNATURE = "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;";
    private final static String END_METHOD = "endHttpService";
    private static final String END_SIGNATURE = "(Ljava/lang/Object;Ljava/lang/Throwable;)V";
    private final static String REJECT = "reject";
    private static final String REJECT_SIGNATURE = "(Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;";
    private Label startFinally = new Label();
    private boolean httpservlet;

    public HttpServiceMV(int access, String desc, MethodVisitor mv, boolean httpservlet) {
        super(ASM7, access, desc, mv);
        this.httpservlet = httpservlet;
    }

    private int statIdx;

    @Override
    public void visitCode() {
        mv.visitVarInsn(Opcodes.ALOAD, 1);
        mv.visitVarInsn(Opcodes.ALOAD, 2);
        if (httpservlet) {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, START_SERVICE, START_SIGNATURE, false);
        } else {
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, START_FILTER, START_SIGNATURE, false);
        }
        statIdx = newLocal(Type.getType(Object.class));
        mv.visitVarInsn(Opcodes.ASTORE, statIdx);
        mv.visitLabel(startFinally);
        mv.visitVarInsn(Opcodes.ALOAD, statIdx);
        mv.visitVarInsn(Opcodes.ALOAD, 1);
        mv.visitVarInsn(Opcodes.ALOAD, 2);
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, REJECT, REJECT_SIGNATURE, false);
        Label end = new Label();
        mv.visitJumpInsn(IFNULL, end);
        mv.visitInsn(Opcodes.RETURN);
        mv.visitLabel(end);
        mv.visitCode();
    }

    @Override
    public void visitInsn(int opcode) {
        if ((opcode >= IRETURN && opcode <= RETURN)) {
            mv.visitVarInsn(Opcodes.ALOAD, statIdx);
            mv.visitInsn(Opcodes.ACONST_NULL);
            mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, END_METHOD, END_SIGNATURE, false);
        }
        mv.visitInsn(opcode);
    }

    @Override
    public void visitMaxs(int maxStack, int maxLocals) {
        Label endFinally = new Label();
        mv.visitTryCatchBlock(startFinally, endFinally, endFinally, null);
        mv.visitLabel(endFinally);
        mv.visitInsn(DUP);
        int errIdx = newLocal(Type.getType(Throwable.class));
        mv.visitVarInsn(Opcodes.ASTORE, errIdx);
        mv.visitVarInsn(Opcodes.ALOAD, statIdx);
        mv.visitVarInsn(Opcodes.ALOAD, errIdx);
        mv.visitMethodInsn(Opcodes.INVOKESTATIC, TRACEMAIN, END_METHOD, END_SIGNATURE, false);
        mv.visitInsn(ATHROW);
        mv.visitMaxs(maxStack + 8, maxLocals + 2);
    }
}