2 * Copyright (C) 2014, United States Government, as represented by the
3 * Administrator of the National Aeronautics and Space Administration.
6 * The Java Pathfinder core (jpf-core) platform is licensed under the
7 * Apache License, Version 2.0 (the "License"); you may not use this file except
8 * in compliance with the License. You may obtain a copy of the License at
10 * http://www.apache.org/licenses/LICENSE-2.0.
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
18 package gov.nasa.jpf.listener;
20 import gov.nasa.jpf.Config;
21 import gov.nasa.jpf.JPF;
22 import gov.nasa.jpf.ListenerAdapter;
23 import gov.nasa.jpf.search.Search;
24 import gov.nasa.jpf.jvm.bytecode.*;
25 import gov.nasa.jpf.vm.*;
26 import gov.nasa.jpf.vm.bytecode.LocalVariableInstruction;
27 import gov.nasa.jpf.vm.bytecode.ReadInstruction;
28 import gov.nasa.jpf.vm.bytecode.StoreInstruction;
29 import gov.nasa.jpf.vm.bytecode.WriteInstruction;
31 import java.io.PrintWriter;
36 * Listener using data flow analysis to find conflicts between smartApps.
39 public class ConflictTracker extends ListenerAdapter {
41 private final PrintWriter out;
42 private final HashSet<String> conflictSet = new HashSet<String>(); // Variables we want to track
43 private final HashSet<String> appSet = new HashSet<String>(); // Apps we want to find their conflicts
44 private final HashSet<String> manualSet = new HashSet<String>(); // Writer classes with manual inputs to detect direct-direct(No Conflict) interactions
45 private final HashMap<Integer, Node> nodes = new HashMap<Integer, Node>(); // Nodes of a graph
46 private ArrayList<NameValuePair> tempSetSet = new ArrayList<NameValuePair>();
48 private long startTime;
49 private Node parentNode = new Node(-2);
50 private String operation;
51 private String detail;
52 private String errorMessage;
55 private boolean conflictFound = false;
56 private boolean manual = false;
58 private final String SET_LOCATION_METHOD = "setLocationMode";
59 private final String LOCATION_VAR = "locationMode";
61 public ConflictTracker(Config config, JPF jpf) {
62 out = new PrintWriter(System.out, true);
64 String[] conflictVars = config.getStringArray("variables");
65 // We are not tracking anything if it is null
66 if (conflictVars != null) {
67 for (String var : conflictVars) {
71 String[] apps = config.getStringArray("apps");
72 // We are not tracking anything if it is null
74 for (String var : apps) {
78 String[] manualClasses = config.getStringArray("manualClasses");
79 // We are not tracking anything if it is null
80 if (manualClasses != null) {
81 for (String var : manualClasses) {
86 // Timeout input from config is in minutes, so we need to convert into millis
87 timeout = config.getInt("timeout", 0) * 60 * 1000;
88 startTime = System.currentTimeMillis();
91 boolean propagateTheChange(Node currentNode) {
92 HashSet<Node> changed = new HashSet<Node>(currentNode.getSuccessors());
94 while(!changed.isEmpty()) {
95 // Get the first element of HashSet and remove it from the changed set
96 Node nodeToProcess = changed.iterator().next();
97 changed.remove(nodeToProcess);
100 boolean isChanged = updateEdge(currentNode, nodeToProcess);
102 // Check for a conflict in this transition(currentNode -> nodeToProcess)
103 if (checkForConflict(nodeToProcess))
106 // Checking if the out set has changed or not(Add its successors to the change list!)
108 propagateTheChange(nodeToProcess);
115 String createErrorMessage(NameValuePair pair, HashMap<String, String> valueMap, HashMap<String, Integer> writerMap) {
116 String message = "Conflict found between the two apps. App"+pair.getAppNum()+
117 " has written the value: "+pair.getValue()+
118 " to the variable: "+pair.getVarName()+" while App"+
119 writerMap.get(pair.getVarName())+" is overwriting the value: "
120 +valueMap.get(pair.getVarName())+" to the same variable!";
121 System.out.println(message);
125 boolean checkForConflict(Node nodeToProcess) {
126 HashMap<String, String> valueMap = new HashMap<String, String>(); // HashMap from varName to value
127 HashMap<String, Integer> writerMap = new HashMap<String, Integer>(); // HashMap from varName to appNum
129 // Update the valueMap
130 for (int i = 0;i < nodeToProcess.getSetSet().size();i++) {
131 NameValuePair nameValuePair = nodeToProcess.getSetSet().get(i);
133 if (valueMap.containsKey(nameValuePair.getVarName())) {
134 // Check if we have a same writer
135 if (!writerMap.get(nameValuePair.getVarName()).equals(nameValuePair.getAppNum())) {
136 // Check if we have a conflict or not
137 if (!valueMap.get(nameValuePair.getVarName()).equals(nameValuePair.getValue())) {
138 errorMessage = createErrorMessage(nameValuePair, valueMap, writerMap);
140 } else { // We have two writers writing the same value
141 writerMap.put(nameValuePair.getVarName(), 3); // 3 represents both apps
144 // Check if we have more than one value with the same writer
145 if (!valueMap.get(nameValuePair.getVarName()).equals(nameValuePair.getValue())) {
146 valueMap.put(nameValuePair.getVarName(), "twoValue"); // We have one writer writing more than one value in a same event
150 valueMap.put(nameValuePair.getVarName(), nameValuePair.getValue());
151 writerMap.put(nameValuePair.getVarName(), nameValuePair.getAppNum());
155 // Comparing the outSet to setSet
156 for (NameValuePair i : nodeToProcess.getOutSet()) {
157 if (valueMap.containsKey(i.getVarName())) {
158 String value = valueMap.get(i.getVarName());
159 Integer writer = writerMap.get(i.getVarName());
160 if ((value != null)&&(writer != null)) {
161 if (!value.equals(i.getValue())&&!writer.equals(i.getAppNum())) { // We have different values
162 errorMessage = createErrorMessage(i, valueMap, writerMap);
172 boolean updateEdge(Node parentNode, Node currentNode) {
173 ArrayList<NameValuePair> setSet = currentNode.getSetSetMap().get(parentNode);
174 HashSet<String> updatedVarNames = new HashSet<String>();
175 HashMap<Integer, String> writerLastValue = new HashMap<Integer, String>();
177 boolean isChanged = false;
179 if (setSet != null) {
180 for (int i = 0;i < setSet.size();i++) {
181 updatedVarNames.add(setSet.get(i).getVarName());
182 writerLastValue.put(setSet.get(i).getAppNum(), setSet.get(i).getValue());
186 for (NameValuePair i : parentNode.getOutSet()) {
187 if (!updatedVarNames.contains(i.getVarName()))
188 isChanged |= currentNode.getOutSet().add(i);
191 if (setSet != null) {
192 for (int i = 0;i < setSet.size();i++) {
193 if (setSet.get(i).getValue().equals(writerLastValue.get(setSet.get(i).getAppNum()))) {
194 isChanged |= currentNode.getOutSet().add(setSet.get(i));
204 HashSet<Node> predecessors = new HashSet<Node>();
205 HashSet<Node> successors = new HashSet<Node>();
206 HashSet<NameValuePair> outSet = new HashSet<NameValuePair>();
207 ArrayList<NameValuePair> setSet = new ArrayList<NameValuePair>();
208 HashMap<Node, ArrayList<NameValuePair>> setSetMap = new HashMap<Node, ArrayList<NameValuePair>>();
214 void addPredecessor(Node node) {
215 predecessors.add(node);
218 void addSuccessor(Node node) {
219 successors.add(node);
226 HashSet<Node> getPredecessors() {
230 HashSet<Node> getSuccessors() {
234 HashSet<NameValuePair> getOutSet() {
238 ArrayList<NameValuePair> getSetSet() {
242 HashMap<Node, ArrayList<NameValuePair>> getSetSetMap() {
247 static class NameValuePair {
253 NameValuePair(Integer appNum, String value, String varName, boolean isManual) {
254 this.appNum = appNum;
256 this.varName = varName;
257 this.isManual = isManual;
260 void setAppNum(Integer appNum) {
261 this.appNum = appNum;
264 void setValue(String value) {
268 void setVarName(String varName) {
269 this.varName = varName;
272 void setIsManual(String varName) {
273 this.isManual = isManual;
276 Integer getAppNum() {
284 String getVarName() {
288 boolean getIsManual() {
293 public boolean equals(Object o) {
294 if (o instanceof NameValuePair) {
295 NameValuePair other = (NameValuePair) o;
296 if (varName.equals(other.getVarName()))
297 return appNum.equals(other.getAppNum());
303 public int hashCode() {
304 return appNum.hashCode() * 31 + varName.hashCode();
309 public void stateRestored(Search search) {
310 id = search.getStateId();
311 depth = search.getDepth();
312 operation = "restored";
315 out.println("The state is restored to state with id: "+id+", depth: "+depth);
317 // Update the parent node
318 if (nodes.containsKey(id)) {
319 parentNode = nodes.get(id);
321 parentNode = new Node(id);
326 public void searchStarted(Search search) {
327 out.println("----------------------------------- search started");
332 public void stateAdvanced(Search search) {
333 String theEnd = null;
334 id = search.getStateId();
335 depth = search.getDepth();
336 operation = "forward";
338 // Add the node to the list of nodes
339 if (nodes.get(id) == null)
340 nodes.put(id, new Node(id));
342 Node currentNode = nodes.get(id);
344 if ((currentNode.getSetSetMap().get(parentNode) == null) || manual)
345 currentNode.getSetSetMap().put(parentNode, new ArrayList<NameValuePair>());
347 // Update the setSet for the edge
348 currentNode.getSetSetMap().get(parentNode).addAll(tempSetSet);
349 parentNode.getSetSet().addAll(tempSetSet);
350 tempSetSet = new ArrayList<NameValuePair>();
353 // Check for the conflict in this edge
354 conflictFound = checkForConflict(parentNode);
356 if (search.isNewState()) {
362 if (search.isEndState()) {
363 out.println("This is the last state!");
367 out.println("The state is forwarded to state with id: "+id+", depth: "+depth+" which is "+detail+" state: "+"% "+theEnd);
369 // Updating the predecessors for this node
370 // Check if parent node is already in successors of the current node or not
371 if (!(currentNode.getPredecessors().contains(parentNode)))
372 currentNode.addPredecessor(parentNode);
374 // Update the successors for this node
375 // Check if current node is already in successors of the parent node or not
376 if (!(parentNode.getSuccessors().contains(currentNode)))
377 parentNode.addSuccessor(currentNode);
379 // Update the edge and check if the outset of the current node is changed or not to propagate the change
380 boolean isChanged = updateEdge(parentNode, currentNode);
382 // Check if the outSet of this state has changed, update all of its successors' sets if any
384 conflictFound = conflictFound || propagateTheChange(currentNode);
386 // Update the parent node
387 if (nodes.containsKey(id)) {
388 parentNode = nodes.get(id);
390 parentNode = new Node(id);
395 public void stateBacktracked(Search search) {
396 id = search.getStateId();
397 depth = search.getDepth();
398 operation = "backtrack";
401 out.println("The state is backtracked to state with id: "+id+", depth: "+depth);
403 // Update the parent node
404 if (nodes.containsKey(id)) {
405 parentNode = nodes.get(id);
407 parentNode = new Node(id);
412 public void searchFinished(Search search) {
413 out.println("----------------------------------- search finished");
416 private String getValue(ThreadInfo ti, Instruction inst, byte type) {
420 frame = ti.getTopFrame();
422 if ((inst instanceof JVMLocalVariableInstruction) ||
423 (inst instanceof JVMFieldInstruction))
425 if (frame.getTopPos() < 0)
429 hi = frame.getTopPos() >= 1 ? frame.peek(1) : 0;
431 return(decodeValue(type, lo, hi));
434 if (inst instanceof JVMArrayElementInstruction)
435 return(getArrayValue(ti, type));
440 private final static String decodeValue(byte type, int lo, int hi) {
442 case Types.T_ARRAY: return(null);
443 case Types.T_VOID: return(null);
445 case Types.T_BOOLEAN: return(String.valueOf(Types.intToBoolean(lo)));
446 case Types.T_BYTE: return(String.valueOf(lo));
447 case Types.T_CHAR: return(String.valueOf((char) lo));
448 case Types.T_DOUBLE: return(String.valueOf(Types.intsToDouble(lo, hi)));
449 case Types.T_FLOAT: return(String.valueOf(Types.intToFloat(lo)));
450 case Types.T_INT: return(String.valueOf(lo));
451 case Types.T_LONG: return(String.valueOf(Types.intsToLong(lo, hi)));
452 case Types.T_SHORT: return(String.valueOf(lo));
454 case Types.T_REFERENCE:
455 ElementInfo ei = VM.getVM().getHeap().get(lo);
459 ClassInfo ci = ei.getClassInfo();
463 if (ci.getName().equals("java.lang.String"))
464 return('"' + ei.asString() + '"');
466 return(ei.toString());
469 System.err.println("Unknown type: " + type);
474 private String getArrayValue(ThreadInfo ti, byte type) {
478 frame = ti.getTopFrame();
480 hi = frame.getTopPos() >= 1 ? frame.peek(1) : 0;
482 return(decodeValue(type, lo, hi));
485 private byte getType(ThreadInfo ti, Instruction inst) {
490 frame = ti.getTopFrame();
491 if ((frame.getTopPos() >= 0) && (frame.isOperandRef())) {
492 return (Types.T_REFERENCE);
497 if (inst instanceof JVMLocalVariableInstruction) {
498 type = ((JVMLocalVariableInstruction) inst).getLocalVariableType();
499 } else if (inst instanceof JVMFieldInstruction){
500 fi = ((JVMFieldInstruction) inst).getFieldInfo();
504 if (inst instanceof JVMArrayElementInstruction) {
505 return (getTypeFromInstruction(inst));
509 return (Types.T_VOID);
512 return (decodeType(type));
515 private final static byte getTypeFromInstruction(Instruction inst) {
516 if (inst instanceof JVMArrayElementInstruction)
517 return(getTypeFromInstruction((JVMArrayElementInstruction) inst));
519 return(Types.T_VOID);
522 private final static byte decodeType(String type) {
523 if (type.charAt(0) == '?'){
524 return(Types.T_REFERENCE);
526 return Types.getBuiltinType(type);
530 // Find the variable writer
531 // It should be one of the apps listed in the .jpf file
532 private String getWriter(List<StackFrame> sfList, HashSet<String> writerSet) {
533 // Start looking from the top of the stack backward
534 for(int i=sfList.size()-1; i>=0; i--) {
535 MethodInfo mi = sfList.get(i).getMethodInfo();
536 if(!mi.isJPFInternal()) {
537 String method = mi.getStackTraceName();
538 // Check against the writers in the writerSet
539 for(String writer : writerSet) {
540 if (method.contains(writer)) {
550 private void writeWriterAndValue(String writer, String value, String var) {
551 // Update the temporary Set set.
552 NameValuePair temp = new NameValuePair(1, value, var, manual);
553 if (writer.equals("App2"))
554 temp = new NameValuePair(2, value, var, manual);
556 tempSetSet.add(temp);
560 public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
562 if (System.currentTimeMillis() - startTime > timeout) {
563 StringBuilder sbTimeOut = new StringBuilder();
564 sbTimeOut.append("Execution timeout: " + (timeout / (60 * 1000)) + " minutes have passed!");
565 Instruction nextIns = ti.createAndThrowException("java.lang.RuntimeException", sbTimeOut.toString());
566 ti.setNextPC(nextIns);
571 StringBuilder sb = new StringBuilder();
572 sb.append(errorMessage);
573 Instruction nextIns = ti.createAndThrowException("java.lang.RuntimeException", sb.toString());
574 ti.setNextPC(nextIns);
576 if (conflictSet.contains(LOCATION_VAR)) {
577 MethodInfo mi = executedInsn.getMethodInfo();
578 // Find the last load before return and get the value here
579 if (mi.getName().equals(SET_LOCATION_METHOD) &&
580 executedInsn instanceof ALOAD && nextInsn instanceof ARETURN) {
581 byte type = getType(ti, executedInsn);
582 String value = getValue(ti, executedInsn, type);
584 // Extract the writer app name
585 ClassInfo ci = mi.getClassInfo();
586 String writer = ci.getName();
588 // Update the temporary Set set.
589 writeWriterAndValue(writer, value, LOCATION_VAR);
592 if (executedInsn instanceof WriteInstruction) {
593 String varId = ((WriteInstruction) executedInsn).getFieldInfo().getFullName();
595 for (String var : conflictSet) {
596 if (varId.contains(var)) {
598 byte type = getType(ti, executedInsn);
599 String value = getValue(ti, executedInsn, type);
600 String writer = getWriter(ti.getStack(), appSet);
601 // Just return if the writer is not one of the listed apps in the .jpf file
605 if (getWriter(ti.getStack(), manualSet) != null)
608 // Update the temporary Set set.
609 writeWriterAndValue(writer, value, var);