Java tutorial
/****************************************************************************** * Copyright (c) 2002 - 2016 IBM Corporation. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * Brian Pfretzschner - initial implementation *****************************************************************************/ package com.ibm.wala.cast.js.nodejs; import java.io.File; import java.io.IOException; import java.util.HashMap; import java.util.HashSet; import java.util.LinkedList; import java.util.List; import java.util.Set; import org.apache.commons.io.FileUtils; import org.json.JSONObject; import com.ibm.wala.cast.js.ipa.callgraph.JSCallGraphUtil; import com.ibm.wala.cast.js.loader.JavaScriptLoader; import com.ibm.wala.cast.js.ssa.JavaScriptInvoke; import com.ibm.wala.cast.js.types.JavaScriptTypes; import com.ibm.wala.cast.types.AstMethodReference; import com.ibm.wala.classLoader.CallSiteReference; import com.ibm.wala.classLoader.IClass; import com.ibm.wala.classLoader.IMethod; import com.ibm.wala.classLoader.SourceFileModule; import com.ibm.wala.classLoader.SourceModule; import com.ibm.wala.ipa.callgraph.CGNode; import com.ibm.wala.ipa.callgraph.MethodTargetSelector; import com.ibm.wala.ipa.callgraph.propagation.ConcreteTypeKey; import com.ibm.wala.ipa.callgraph.propagation.ConstantKey; import com.ibm.wala.ipa.callgraph.propagation.InstanceKey; import com.ibm.wala.ipa.callgraph.propagation.PointerAnalysis; import com.ibm.wala.ipa.callgraph.propagation.PointerKey; import com.ibm.wala.ipa.callgraph.propagation.PropagationCallGraphBuilder; import com.ibm.wala.ssa.IR; import com.ibm.wala.ssa.SSAAbstractInvokeInstruction; import com.ibm.wala.types.TypeReference; import com.ibm.wala.util.collections.HashMapFactory; import com.ibm.wala.util.collections.HashSetFactory; import com.ibm.wala.util.intset.OrdinalSet; import com.ibm.wala.util.ssa.ClassLookupException; /** * This class is used by WALA internals to resolve to what functions a call * could potentially invoke. * * @author Brian Pfretzschner <brian.pfretzschner@gmail.com> */ public class NodejsRequireTargetSelector implements MethodTargetSelector { private File rootDir; private MethodTargetSelector base; private PropagationCallGraphBuilder builder; private HashMap<String, IMethod> previouslyRequired = HashMapFactory.make(); public NodejsRequireTargetSelector(File rootDir, MethodTargetSelector base) { this.rootDir = rootDir; this.base = base; } public void setCallGraphBuilder(PropagationCallGraphBuilder builder) { this.builder = builder; } /** * Basic idea: If the called method is named "__WALA__require", it is most likely * the require-function mock from the module-wrapper. To figure out what file * shall be required, pointer analysis is used to identify strings that can * flow into the require call. That file is than loaded, wrapped into the * module wrapper and returned as method that will be invoked. Therefore, * there will never be an call graph edge to the require function call, * the require function is replaced by the file that is included through * the require call. * * {@inheritDoc} */ @Override public IMethod getCalleeTarget(CGNode caller, CallSiteReference site, IClass receiver) { PointerAnalysis<InstanceKey> pointerAnalysis = builder.getPointerAnalysis(); JavaScriptLoader jsLoader = (JavaScriptLoader) builder.getClassHierarchy() .getLoader(JavaScriptTypes.jsLoader); IMethod calledMethod = base.getCalleeTarget(caller, site, receiver); if (calledMethod != null && calledMethod.getDeclaringClass().toString().endsWith("/__WALA__require")) { JavaScriptInvoke callInstr = getInvokeInstruction(caller, site); Set<String> targets = getRequireTargets(pointerAnalysis, caller, callInstr); if (targets.size() == 0) { // There is no possible call target throw new RuntimeException("No require target found in method: " + caller.getMethod()); } for (String target : targets) { try { File workingDir = new File(receiver.getSourceFileName()).getParentFile(); SourceModule sourceModule = resolve(rootDir, workingDir, target); if (previouslyRequired.containsKey(sourceModule.getClassName())) { return previouslyRequired.get(sourceModule.getClassName()); } String className = "L" + sourceModule.getClassName() + "/nodejsModule"; if (sourceModule instanceof NodejsRequiredSourceModule && ((NodejsRequiredSourceModule) sourceModule).getFile().toString().endsWith(".json")) { className = "L" + sourceModule.getClassName() + "/jsonModule"; } JSCallGraphUtil.loadAdditionalFile(builder.getClassHierarchy(), jsLoader, sourceModule); IClass script = builder.getClassHierarchy() .lookupClass(TypeReference.findOrCreate(jsLoader.getReference(), className)); IMethod method = script.getMethod(AstMethodReference.fnSelector); previouslyRequired.put(sourceModule.getClassName(), method); return method; } catch (IOException e) { e.printStackTrace(); } } } return calledMethod; } private static JavaScriptInvoke getInvokeInstruction(CGNode caller, CallSiteReference site) { IR callerIR = caller.getIR(); SSAAbstractInvokeInstruction callInstrs[] = callerIR.getCalls(site); assert callInstrs.length == 1; return (JavaScriptInvoke) callInstrs[0]; } private Set<String> getRequireTargets(PointerAnalysis<InstanceKey> pointerAnalysis, CGNode caller, JavaScriptInvoke callInstr) { HashSet<String> set = HashSetFactory.make(); PointerKey pk = builder.getPointerKeyForLocal(caller, callInstr.getUse(2)); OrdinalSet<InstanceKey> instanceKeys = pointerAnalysis.getPointsToSet(pk); for (InstanceKey instanceKey : instanceKeys) { if (instanceKey instanceof ConstantKey<?>) { Object value = ((ConstantKey<?>) instanceKey).getValue(); if (value instanceof String) { set.add((String) value); } else { System.err.println("NodejsRequireTargetSelector: Unexpected value: " + value); return HashSetFactory.make(); } } else if (instanceKey instanceof ConcreteTypeKey) { // Cannot do anything with this information... } else { System.err.println("NodejsRequireTargetSelector: Unexpected instanceKey: " + instanceKey.getClass() + " -- " + instanceKey); return HashSetFactory.make(); } } return set; } /** * Implements the Nodejs require.resolve algorithm, * see https://nodejs.org/api/modules.html#modules_all_together * * require(X) from module at path Y * 1. If X is a core module, * a. return the core module * b. STOP * 2. If X begins with './' or '/' or '../' * a. LOAD_AS_FILE(Y + X) * b. LOAD_AS_DIRECTORY(Y + X) * 3. LOAD_NODE_MODULES(X, dirname(Y)) * 4. THROW "not found" * * @param dir Y in the pseudo algorithm * @param target X in the pseudo algorithm * @throws IOException */ public static SourceFileModule resolve(File rootDir, File dir, String target) throws IOException { if (NodejsRequiredCoreModule.isCoreModule(target)) return NodejsRequiredCoreModule.make(target); if (target.startsWith("./") || target.startsWith("/") || target.startsWith("../")) { SourceFileModule module = loadAsFile(rootDir, new File(dir, target)); if (module != null) return module; module = loadAsDirectory(rootDir, new File(dir, target)); if (module != null) return module; } SourceFileModule module = loadNodeModules(rootDir, dir, target); if (module != null) return module; throw new ClassLookupException("Required module not found: " + target + " in " + dir); } /** * LOAD_AS_FILE(X) * 1. If X is a file, load X as JavaScript text. STOP * 2. If X.js is a file, load X.js as JavaScript text. STOP * 3. If X.json is a file, parse X.json to a JavaScript Object. STOP * 4. If X.node is a file, load X.node as binary addon. STOP * * @param f * @throws IOException */ private static SourceFileModule loadAsFile(File rootDir, File f) throws IOException { // 1. if (f.isFile()) return NodejsRequiredSourceModule.make(rootDir, f); // 2. File jsFile = new File(f + ".js"); if (jsFile.isFile()) return NodejsRequiredSourceModule.make(rootDir, jsFile); // 3. File jsonFile = new File(f + ".json"); if (jsonFile.isFile()) return NodejsRequiredSourceModule.make(rootDir, jsonFile); // Skip 4. step return null; } /** * LOAD_AS_DIRECTORY(X) * 1. If X/package.json is a file, * a. Parse X/package.json, and look for "main" field. * b. let M = X + (json main field) * c. LOAD_AS_FILE(M) * 2. If X/index.js is a file, load X/index.js as JavaScript text. STOP * 3. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP * 4. If X/index.node is a file, load X/index.node as binary addon. STOP * * @param d * @throws IOException */ private static SourceFileModule loadAsDirectory(File rootDir, File d) throws IOException { // 1. File packageJsonFile = new File(d, "package.json"); if (packageJsonFile.isFile()) { // 1.a. String packageJsonContent = FileUtils.readFileToString(packageJsonFile); JSONObject packageJson = new JSONObject(packageJsonContent); if (packageJson.has("main")) { String mainFileName = packageJson.getString("main"); // 1.b. File mainFile = new File(d, mainFileName); // 1.c. return loadAsFile(rootDir, mainFile); } } // 2. File jsFile = new File(d, "index.js"); if (jsFile.isFile()) return NodejsRequiredSourceModule.make(rootDir, jsFile); // 3. File jsonFile = new File(d, "index.json"); if (jsonFile.isFile()) return NodejsRequiredSourceModule.make(rootDir, jsonFile); // Skip 4. step return null; } /** * LOAD_NODE_MODULES(X, START) * 1. let DIRS=NODE_MODULES_PATHS(START) * 2. for each DIR in DIRS: * a. LOAD_AS_FILE(DIR/X) * b. LOAD_AS_DIRECTORY(DIR/X) * * @param dir * @param target * @throws IOException */ private static SourceFileModule loadNodeModules(File rootDir, File d, String target) throws IOException { List<File> dirs = nodeModulePaths(rootDir, d); for (File dir : dirs) { SourceFileModule module = loadAsFile(rootDir, new File(dir, target)); if (module != null) return module; module = loadAsDirectory(rootDir, new File(dir, target)); if (module != null) return module; } return null; } /** * NODE_MODULES_PATHS(START) * 1. let PARTS = path split(START) * 2. let I = count of PARTS - 1 * 3. let DIRS = [] * 4. while I >= 0, * a. if PARTS[I] = "node_modules" CONTINUE * b. DIR = path join(PARTS[0 .. I] + "node_modules") * c. DIRS = DIRS + DIR * d. let I = I - 1 * 5. return DIRS * * @param d * @throws IOException */ private static List<File> nodeModulePaths(File rootDir, File d) throws IOException { LinkedList<File> dirs = new LinkedList<>(); while (d.getCanonicalPath().startsWith(rootDir.getCanonicalPath()) && d.toPath().getNameCount() > 0) { // 4.a. if (!d.getName().equals("node_modules")) { // 4.b. and 4.c. dirs.add(new File(d, "node_modules")); } // 4.d. d = d.getParentFile(); } return dirs; } }