AndroidLogger.java

package dev.navids.soottutorial.android;

import soot.*;
import soot.jimple.*;

import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;

public class AndroidLogger {

    private final static String USER_HOME = System.getProperty("user.home");
    private static String androidJar = USER_HOME + "/Library/Android/sdk/platforms";
    static String androidDemoPath = System.getProperty("user.dir") + File.separator + "demo" + File.separator + "Android";
    static String apkPath = androidDemoPath + File.separator + "/calc.apk";
    static String outputPath = androidDemoPath + File.separator + "/Instrumented";


    public static void main(String[] args){

        if(System.getenv().containsKey("ANDROID_HOME"))
            androidJar = System.getenv("ANDROID_HOME")+ File.separator+"platforms";
        // Clean the outputPath
        final File[] files = (new File(outputPath)).listFiles();
        if (files != null && files.length > 0) {
            Arrays.asList(files).forEach(File::delete);
        }
        // Initialize Soot
        InstrumentUtil.setupSoot(androidJar, apkPath, outputPath);
        // Add a transformation pack in order to add the statement "System.out.println(<content>) at the beginning of each Application method
        PackManager.v().getPack("jtp").add(new Transform("jtp.myLogger", new BodyTransformer() {
            @Override
            protected void internalTransform(Body b, String phaseName, Map<String, String> options) {
                // First we filter out Android framework methods
                if(AndroidUtil.isAndroidMethod(b.getMethod()))
                    return;
                JimpleBody body = (JimpleBody) b;
                UnitPatchingChain units = b.getUnits();
                List<Unit> generatedUnits = new ArrayList<>();

                // The message that we want to log
                String content = String.format("%s Beginning of method %s", InstrumentUtil.TAG, body.getMethod().getSignature());
                // In order to call "System.out.println" we need to create a local containing "System.out" value
                Local psLocal = InstrumentUtil.generateNewLocal(body, RefType.v("java.io.PrintStream"));
                // Now we assign "System.out" to psLocal
                SootField sysOutField = Scene.v().getField("<java.lang.System: java.io.PrintStream out>");
                AssignStmt sysOutAssignStmt = Jimple.v().newAssignStmt(psLocal, Jimple.v().newStaticFieldRef(sysOutField.makeRef()));
                generatedUnits.add(sysOutAssignStmt);

                // Create println method call and provide its parameter
                SootMethod printlnMethod = Scene.v().grabMethod("<java.io.PrintStream: void println(java.lang.String)>");
                Value printlnParamter = StringConstant.v(content);
                InvokeStmt printlnMethodCallStmt = Jimple.v().newInvokeStmt(Jimple.v().newVirtualInvokeExpr(psLocal, printlnMethod.makeRef(), printlnParamter));
                generatedUnits.add(printlnMethodCallStmt);

                // Insert the generated statement before the first  non-identity stmt
                units.insertBefore(generatedUnits, body.getFirstNonIdentityStmt());
                // Validate the body to ensure that our code injection does not introduce any problem (at least statically)
                b.validate();
            }
        }));
        // Run Soot packs (note that our transformer pack is added to the phase "jtp")
        PackManager.v().runPacks();
        // Write the result of packs in outputPath
        PackManager.v().writeOutput();
    }
}