java/src/main/com/google/appengine/tools/development/agent/impl/ObjectAccessVisitor.java

   1 // Copyright 2009 Google Inc. All Rights Reserved.
   2
   3 package com.google.appengine.tools.development.agent.impl;
   4
   5 import org.objectweb.asm.ClassAdapter;
   6 import org.objectweb.asm.ClassVisitor;
   7 import org.objectweb.asm.MethodVisitor;
   8 import org.objectweb.asm.Opcodes;
   9
  10 import java.net.URL;
  11 import java.util.HashSet;
  12 import java.util.Set;
  13
  14 /**
  15  * Visits method and field instructions, checking for references to
  16  * blacklisted classes.
  17  *
  18  */
  19 public class ObjectAccessVisitor extends ClassAdapter {
  20
  21   private static final String REJECT = "reject";
  22
  23   private static final String REJECT_DESCRIPTOR = "(Ljava/lang/String;)V";
  24
  25   private static final String CHECK_RESTRICTED = "checkRestricted";
  26
  27   private static final String CHECK_RESTRICTED_DESCRIPTOR =
  28       "(ZLjava/lang/String;Ljava/lang/String;Ljava/lang/String;)V";
  29
  30   private final boolean isUserCode;
  31   private final boolean treatRestrictedListViolationsAsErrors;
  32   private final String callingClassName;
  33   private final String callingClassCodeSource;
  34   private final Set<String> referencedClasses = new HashSet<String>();
  35
  36   public ObjectAccessVisitor(
  37       ClassVisitor classVisitor, boolean isUserCode,
  38       boolean treatRestrictedListViolationsAsErrors, String callingClassName, URL callingClassCodeSource) {
  39     super(classVisitor);
  40     this.isUserCode = isUserCode;
  41     this.treatRestrictedListViolationsAsErrors = treatRestrictedListViolationsAsErrors;
  42     this.callingClassName = callingClassName;
  43     this.callingClassCodeSource =
  44         callingClassCodeSource == null ? "unknown location" : callingClassCodeSource.toString();
  45   }
  46
  47   @Override
  48   public MethodVisitor visitMethod(int access, String name, String desc, String signature,
  49       String[] exceptions) {
  50     MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
  51     return (mv == null) ? null : new MethodTranslator(mv, access, name, desc);
  52   }
  53
  54   private class MethodTranslator extends NonRecordingGeneratorAdapter {
  55     MethodTranslator(MethodVisitor methodVisitor, int access, String name, String desc) {
  56       super(methodVisitor, access, name, desc);
  57     }
  58
  59     @Override
  60     public void visitFieldInsn(int opcode, String owner, String name, String desc) {
  61       maybeReject(owner);
  62       super.visitFieldInsn(opcode, owner, name, desc);
  63     }
  64
  65     @Override
  66     public void visitMethodInsn(int opcode, String owner, String name, String desc) {
  67       maybeReject(owner);
  68       super.visitMethodInsn(opcode, owner, name, desc);
  69     }
  70
  71     private void maybeReject(String klass) {
  72       if (BlackList.getBlackList().contains(klass)) {
  73         super.push(klass.replace('/', '.'));
  74         super.visitMethodInsn(Opcodes.INVOKESTATIC, AgentImpl.AGENT_RUNTIME,
  75             REJECT, REJECT_DESCRIPTOR);
  76       } else if (isUserCode && !referencedClasses.contains(klass)) {
  77         referencedClasses.add(klass);
  78         super.push(treatRestrictedListViolationsAsErrors);
  79         super.push(klass.replace('/', '.'));
  80         super.push(callingClassName);
  81         super.push(callingClassCodeSource);
  82         super.visitMethodInsn(Opcodes.INVOKESTATIC, AgentImpl.AGENT_RUNTIME,
  83             CHECK_RESTRICTED, CHECK_RESTRICTED_DESCRIPTOR);
  84       }
  85     }
  86   }
  87 }