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 String NAME = "Apache Commons BCEL";
047    static final String BANNER = NAME + "\nhttps://commons.apache.org/bcel\n";
048
049    static final Verifier[] EMPTY_ARRAY = {};
050
051    /**
052     * Verifies class files. This is a simple demonstration of how the API of BCEL's class file verifier "JustIce" may be
053     * used. You should supply command-line arguments which are fully qualified namea of the classes to verify. These class
054     * files must be somewhere in your CLASSPATH (refer to Sun's documentation for questions about this) or you must have
055     * put the classes into the BCEL Repository yourself (via 'addClass(JavaClass)').
056     */
057    public static void main(final String[] args) {
058        System.out.println(BANNER);
059        for (int index = 0; index < args.length; index++) {
060            try {
061                if (args[index].endsWith(JavaClass.EXTENSION)) {
062                    final int dotclasspos = args[index].lastIndexOf(JavaClass.EXTENSION);
063                    if (dotclasspos != -1) {
064                        args[index] = args[index].substring(0, dotclasspos);
065                    }
066                }
067                args[index] = Utility.pathToPackage(args[index]);
068                System.out.println("Now verifying: " + args[index] + "\n");
069                verifyType(args[index]);
070                org.apache.bcel.Repository.clearCache();
071                System.gc();
072            } catch (final ClassNotFoundException e) {
073                e.printStackTrace();
074            }
075        }
076    }
077
078    static void verifyType(final String fullyQualifiedClassName) throws ClassNotFoundException {
079        final Verifier verifier = VerifierFactory.getVerifier(fullyQualifiedClassName);
080        VerificationResult verificationResult;
081        verificationResult = verifier.doPass1();
082        System.out.println("Pass 1:\n" + verificationResult);
083        verificationResult = verifier.doPass2();
084        System.out.println("Pass 2:\n" + verificationResult);
085        if (verificationResult == VerificationResult.VR_OK) {
086            final JavaClass jc = org.apache.bcel.Repository.lookupClass(fullyQualifiedClassName);
087            for (int i = 0; i < jc.getMethods().length; i++) {
088                verificationResult = verifier.doPass3a(i);
089                System.out.println("Pass 3a, method number " + i + " ['" + jc.getMethods()[i] + "']:\n" + verificationResult);
090                verificationResult = verifier.doPass3b(i);
091                System.out.println("Pass 3b, method number " + i + " ['" + jc.getMethods()[i] + "']:\n" + verificationResult);
092            }
093        }
094        System.out.println("Warnings:");
095        final String[] warnings = verifier.getMessages();
096        if (warnings.length == 0) {
097            System.out.println("<none>");
098        }
099        for (final String warning : warnings) {
100            System.out.println(warning);
101        }
102        System.out.println("\n");
103        // avoid swapping.
104        verifier.flush();
105    }
106
107    /**
108     * The name of the class this verifier operates on.
109     */
110    private final String className;
111
112    /** A Pass1Verifier for this Verifier instance. */
113    private Pass1Verifier p1v;
114
115    /** A Pass2Verifier for this Verifier instance. */
116    private Pass2Verifier p2v;
117
118    /** The Pass3aVerifiers for this Verifier instance. Key: Interned string specifying the method number. */
119    private final Map<String, Pass3aVerifier> p3avs = new HashMap<>();
120
121    /** The Pass3bVerifiers for this Verifier instance. Key: Interned string specifying the method number. */
122    private final Map<String, Pass3bVerifier> p3bvs = new HashMap<>();
123
124    /**
125     * Instantiation is done by the VerifierFactory.
126     *
127     * @see VerifierFactory
128     */
129    Verifier(final String fullyQualifiedClassName) {
130        className = fullyQualifiedClassName;
131    }
132
133    /** Returns the VerificationResult for the given pass. */
134    public VerificationResult doPass1() {
135        if (p1v == null) {
136            p1v = new Pass1Verifier(this);
137        }
138        return p1v.verify();
139    }
140
141    /** Returns the VerificationResult for the given pass. */
142    public VerificationResult doPass2() {
143        if (p2v == null) {
144            p2v = new Pass2Verifier(this);
145        }
146        return p2v.verify();
147    }
148
149    /**
150     * Returns the VerificationResult for the given pass.
151     *
152     * @param methodNo The method to verify
153     * @return the VerificationResult
154     */
155    public VerificationResult doPass3a(final int methodNo) {
156        return p3avs.computeIfAbsent(Integer.toString(methodNo), k -> new Pass3aVerifier(this, methodNo)).verify();
157    }
158
159    /**
160     * Returns the VerificationResult for the given pass.
161     *
162     * @param methodNo The method to verify
163     * @return the VerificationResult
164     */
165    public VerificationResult doPass3b(final int methodNo) {
166        return p3bvs.computeIfAbsent(Integer.toString(methodNo), k -> new Pass3bVerifier(this, methodNo)).verify();
167    }
168
169    /**
170     * Forget everything known about the class file; that means, really start a new verification of a possibly different
171     * class file from BCEL's repository.
172     */
173    public void flush() {
174        p1v = null;
175        p2v = null;
176        p3avs.clear();
177        p3bvs.clear();
178    }
179
180    /**
181     * Returns the name of the class this verifier operates on. This is particularly interesting when this verifier was
182     * created recursively by another Verifier and you got a reference to this Verifier by the getVerifiers() method of the
183     * VerifierFactory.
184     *
185     * @see VerifierFactory
186     */
187    public final String getClassName() {
188        return className;
189    }
190
191    /**
192     * This returns all the (warning) messages collected during verification. A prefix shows from which verifying pass a
193     * message originates.
194     *
195     * @throws ClassNotFoundException if this class can't be found.
196     */
197    public String[] getMessages() throws ClassNotFoundException {
198        final List<String> messages = new ArrayList<>();
199        if (p1v != null) {
200            p1v.getMessagesList().forEach(element -> messages.add("Pass 1: " + element));
201        }
202        if (p2v != null) {
203            p2v.getMessagesList().forEach(element -> messages.add("Pass 2: " + element));
204        }
205        for (final Pass3aVerifier pv : p3avs.values()) {
206            final int meth = pv.getMethodNo();
207            for (final String element : pv.getMessages()) {
208                messages.add("Pass 3a, method " + meth + " ('" + org.apache.bcel.Repository.lookupClass(className).getMethods()[meth] + "'): " + element);
209            }
210        }
211        for (final Pass3bVerifier pv : p3bvs.values()) {
212            final int meth = pv.getMethodNo();
213            for (final String element : pv.getMessages()) {
214                messages.add("Pass 3b, method " + meth + " ('" + org.apache.bcel.Repository.lookupClass(className).getMethods()[meth] + "'): " + element);
215            }
216        }
217
218        return messages.toArray(ArrayUtils.EMPTY_STRING_ARRAY);
219    }
220}