001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.bcel.verifier;
018
019import java.util.ArrayList;
020import java.util.HashMap;
021import java.util.List;
022import java.util.Map;
023
024import org.apache.bcel.classfile.JavaClass;
025import org.apache.bcel.classfile.Utility;
026import org.apache.bcel.verifier.statics.Pass1Verifier;
027import org.apache.bcel.verifier.statics.Pass2Verifier;
028import org.apache.bcel.verifier.statics.Pass3aVerifier;
029import org.apache.bcel.verifier.structurals.Pass3bVerifier;
030import org.apache.commons.lang3.ArrayUtils;
031
032/**
033 * A Verifier instance is there to verify a class file according to The Java Virtual Machine Specification, 2nd Edition.
034 *
035 * Pass-3b-verification includes pass-3a-verification; pass-3a-verification includes pass-2-verification;
036 * pass-2-verification includes pass-1-verification.
037 *
038 * A Verifier creates PassVerifier instances to perform the actual verification. Verifier instances are usually
039 * generated by the VerifierFactory.
040 *
041 * @see VerifierFactory
042 * @see PassVerifier
043 */
044public class Verifier {
045
046    static final Verifier[] EMPTY_ARRAY = {};
047
048    /**
049     * Verifies class files. This is a simple demonstration of how the API of BCEL's class file verifier "JustIce" may be
050     * used. You should supply command-line arguments which are fully qualified namea of the classes to verify. These class
051     * files must be somewhere in your CLASSPATH (refer to Sun's documentation for questions about this) or you must have
052     * put the classes into the BCEL Repository yourself (via 'addClass(JavaClass)').
053     */
054    public static void main(final String[] args) {
055        System.out.println("JustIce by Enver Haase, (C) 2001-2002.\n<http://bcel.sourceforge.net>\n<https://commons.apache.org/bcel>\n");
056        for (int index = 0; index < args.length; index++) {
057            try {
058                if (args[index].endsWith(".class")) {
059                    final int dotclasspos = args[index].lastIndexOf(".class");
060                    if (dotclasspos != -1) {
061                        args[index] = args[index].substring(0, dotclasspos);
062                    }
063                }
064                args[index] = Utility.pathToPackage(args[index]);
065                System.out.println("Now verifying: " + args[index] + "\n");
066                verifyType(args[index]);
067                org.apache.bcel.Repository.clearCache();
068                System.gc();
069            } catch (final ClassNotFoundException e) {
070                e.printStackTrace();
071            }
072        }
073    }
074
075    static void verifyType(final String fullyQualifiedClassName) throws ClassNotFoundException {
076        final Verifier verifier = VerifierFactory.getVerifier(fullyQualifiedClassName);
077        VerificationResult verificationResult;
078        verificationResult = verifier.doPass1();
079        System.out.println("Pass 1:\n" + verificationResult);
080        verificationResult = verifier.doPass2();
081        System.out.println("Pass 2:\n" + verificationResult);
082        if (verificationResult == VerificationResult.VR_OK) {
083            final JavaClass jc = org.apache.bcel.Repository.lookupClass(fullyQualifiedClassName);
084            for (int i = 0; i < jc.getMethods().length; i++) {
085                verificationResult = verifier.doPass3a(i);
086                System.out.println("Pass 3a, method number " + i + " ['" + jc.getMethods()[i] + "']:\n" + verificationResult);
087                verificationResult = verifier.doPass3b(i);
088                System.out.println("Pass 3b, method number " + i + " ['" + jc.getMethods()[i] + "']:\n" + verificationResult);
089            }
090        }
091        System.out.println("Warnings:");
092        final String[] warnings = verifier.getMessages();
093        if (warnings.length == 0) {
094            System.out.println("<none>");
095        }
096        for (final String warning : warnings) {
097            System.out.println(warning);
098        }
099        System.out.println("\n");
100        // avoid swapping.
101        verifier.flush();
102    }
103
104    /**
105     * The name of the class this verifier operates on.
106     */
107    private final String className;
108
109    /** A Pass1Verifier for this Verifier instance. */
110    private Pass1Verifier p1v;
111
112    /** A Pass2Verifier for this Verifier instance. */
113    private Pass2Verifier p2v;
114
115    /** The Pass3aVerifiers for this Verifier instance. Key: Interned string specifying the method number. */
116    private final Map<String, Pass3aVerifier> p3avs = new HashMap<>();
117
118    /** The Pass3bVerifiers for this Verifier instance. Key: Interned string specifying the method number. */
119    private final Map<String, Pass3bVerifier> p3bvs = new HashMap<>();
120
121    /**
122     * Instantiation is done by the VerifierFactory.
123     *
124     * @see VerifierFactory
125     */
126    Verifier(final String fullyQualifiedClassName) {
127        className = fullyQualifiedClassName;
128    }
129
130    /** Returns the VerificationResult for the given pass. */
131    public VerificationResult doPass1() {
132        if (p1v == null) {
133            p1v = new Pass1Verifier(this);
134        }
135        return p1v.verify();
136    }
137
138    /** Returns the VerificationResult for the given pass. */
139    public VerificationResult doPass2() {
140        if (p2v == null) {
141            p2v = new Pass2Verifier(this);
142        }
143        return p2v.verify();
144    }
145
146    /**
147     * Returns the VerificationResult for the given pass.
148     * 
149     * @param methodNo The method to verify
150     * @return the VerificationResult 
151     */
152    public VerificationResult doPass3a(final int methodNo) {
153        return p3avs.computeIfAbsent(Integer.toString(methodNo), k -> new Pass3aVerifier(this, methodNo)).verify();
154    }
155
156    /**
157     * Returns the VerificationResult for the given pass.
158     * 
159     * @param methodNo The method to verify
160     * @return the VerificationResult 
161     */
162    public VerificationResult doPass3b(final int methodNo) {
163        return p3bvs.computeIfAbsent(Integer.toString(methodNo), k -> new Pass3bVerifier(this, methodNo)).verify();
164    }
165
166    /**
167     * Forget everything known about the class file; that means, really start a new verification of a possibly different
168     * class file from BCEL's repository.
169     */
170    public void flush() {
171        p1v = null;
172        p2v = null;
173        p3avs.clear();
174        p3bvs.clear();
175    }
176
177    /**
178     * Returns the name of the class this verifier operates on. This is particularly interesting when this verifier was
179     * created recursively by another Verifier and you got a reference to this Verifier by the getVerifiers() method of the
180     * VerifierFactory.
181     *
182     * @see VerifierFactory
183     */
184    public final String getClassName() {
185        return className;
186    }
187
188    /**
189     * This returns all the (warning) messages collected during verification. A prefix shows from which verifying pass a
190     * message originates.
191     */
192    public String[] getMessages() throws ClassNotFoundException {
193        final List<String> messages = new ArrayList<>();
194        if (p1v != null) {
195            p1v.getMessagesList().forEach(element -> messages.add("Pass 1: " + element));
196        }
197        if (p2v != null) {
198            p2v.getMessagesList().forEach(element -> messages.add("Pass 2: " + element));
199        }
200        for (final Pass3aVerifier pv : p3avs.values()) {
201            final int meth = pv.getMethodNo();
202            for (final String element : pv.getMessages()) {
203                messages.add("Pass 3a, method " + meth + " ('" + org.apache.bcel.Repository.lookupClass(className).getMethods()[meth] + "'): " + element);
204            }
205        }
206        for (final Pass3bVerifier pv : p3bvs.values()) {
207            final int meth = pv.getMethodNo();
208            for (final String element : pv.getMessages()) {
209                messages.add("Pass 3b, method " + meth + " ('" + org.apache.bcel.Repository.lookupClass(className).getMethods()[meth] + "'): " + element);
210            }
211        }
212
213        return messages.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
214    }
215}