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 {
40 private final PrintWriter out;
41 private final HashSet<String> conflictSet = new HashSet<String>(); // Variables we want to track
42 private final HashSet<String> appSet = new HashSet<String>(); // Apps we want to find their conflicts
43 private final HashSet<String> manualSet = new HashSet<String>(); // Writer classes with manual inputs to detect direct-direct(No Conflict) interactions
44 private final HashMap<Integer, Node> nodes = new HashMap<Integer, Node>(); // Nodes of a graph
45 private ArrayList<NameValuePair> tempSetSet = new ArrayList<NameValuePair>();
47 private long startTime;
48 private Node parentNode = new Node(-2);
49 private String operation;
50 private String detail;
51 private String errorMessage;
54 private boolean conflictFound = false;
55 private boolean manual = false;
57 private final String SET_LOCATION_METHOD = "setLocationMode";
58 private final String LOCATION_VAR = "locationMode";
60 public ConflictTracker(Config config, JPF jpf) {
61 out = new PrintWriter(System.out, true);
63 String[] conflictVars = config.getStringArray("variables");
64 // We are not tracking anything if it is null
65 if (conflictVars != null) {
66 for (String var : conflictVars) {
70 String[] apps = config.getStringArray("apps");
71 // We are not tracking anything if it is null
73 for (String var : apps) {
77 String[] manualClasses = config.getStringArray("manualClasses");
78 // We are not tracking anything if it is null
79 if (manualClasses != null) {
80 for (String var : manualClasses) {
85 // Timeout input from config is in minutes, so we need to convert into millis
86 timeout = config.getInt("timeout", 0) * 60 * 1000;
87 startTime = System.currentTimeMillis();
90 boolean propagateTheChange(Node currentNode) {
91 HashSet<Node> changed = new HashSet<Node>(currentNode.getSuccessors());
92 HashMap<Node, HashSet<Node>> parentQueueMap = new HashMap<Node, HashSet<Node>>();
93 HashSet<Node> parents = new HashSet<Node>();
94 parents.add(currentNode);
96 for (Node node : currentNode.getSuccessors()) {
97 parentQueueMap.put(node, parents);
100 while(!changed.isEmpty()) {
101 // Get the first element of the changed set and remove it
102 Node nodeToProcess = changed.iterator().next();
103 changed.remove(nodeToProcess);
105 // Update the changed parents
106 parents = parentQueueMap.get(nodeToProcess);
107 boolean isChanged = false;
109 for (Node node : parents) {
111 isChanged |= updateTheOutSet(node, nodeToProcess);
114 // Check for a conflict if the outSet of nodeToProcess is changed
116 for (Node node : nodeToProcess.getSuccessors()) {
117 HashMap<Transition, ArrayList<NameValuePair>> setSets = nodeToProcess.getOutgoingEdges().get(node).getSetSetMap();
118 for (Map.Entry mapElement : setSets.entrySet()) {
119 Transition transition = (Transition)mapElement.getKey();
120 if (checkForConflict(nodeToProcess, node, transition))
126 // Update the parents list for the successors of the current node
127 parents = new HashSet<Node>();
128 parents.add(nodeToProcess);
130 // Checking if the out set has changed or not(Add its successors to the change list!)
132 for (Node i : nodeToProcess.getSuccessors()) {
133 if (!changed.contains(i))
136 // Update the list of updated parents for the current node
137 if (parentQueueMap.containsKey(i))
138 parentQueueMap.get(i).add(nodeToProcess);
140 parentQueueMap.put(i, parents);
148 String createErrorMessage(NameValuePair pair, HashMap<String, String> valueMap, HashMap<String, Integer> writerMap) {
149 String message = "Conflict found between the two apps. App"+pair.getAppNum()+
150 " has written the value: "+pair.getValue()+
151 " to the variable: "+pair.getVarName()+" while App"
152 +writerMap.get(pair.getVarName())+" is overwriting the value: "
153 +valueMap.get(pair.getVarName())+" to the same variable!";
154 System.out.println(message);
158 boolean checkForConflict(Node parentNode, Node currentNode, Transition currentTransition) {
159 ArrayList<NameValuePair> setSet = parentNode.getOutgoingEdges().get(currentNode).getSetSetMap().get(currentTransition);
160 HashMap<String, String> valueMap = new HashMap<String, String>(); // HashMap from varName to value
161 HashMap<String, Integer> writerMap = new HashMap<String, Integer>(); // HashMap from varName to appNum
163 // Update the valueMap and writerMap + check for conflict between the elements of setSet
164 for (int i = 0;i < setSet.size();i++) {
165 NameValuePair nameValuePair = setSet.get(i);
166 String varName = nameValuePair.getVarName();
167 String value = nameValuePair.getValue();
168 Integer appNum = nameValuePair.getAppNum();
170 if (valueMap.containsKey(varName)) {
171 // Check if we have a same writer
172 if (!writerMap.get(varName).equals(appNum)) {
173 // Check if we have a conflict or not
174 if (!valueMap.get(varName).equals(value)) {
175 errorMessage = createErrorMessage(nameValuePair, valueMap, writerMap);
177 } else { // We have two writers writing the same value
178 writerMap.put(varName, 3); // 3 represents both apps
181 // Check if we have more than one value with the same writer
182 if (!valueMap.get(varName).equals(value)) {
183 // We have one writer writing more than one value in a same event
184 valueMap.put(varName, "twoValue");
188 valueMap.put(varName, value);
189 writerMap.put(varName, appNum);
193 // Check for conflict between outSet and this transition setSet
194 for (NameValuePair i : currentNode.getOutSet()) {
195 if (valueMap.containsKey(i.getVarName())) {
196 String value = valueMap.get(i.getVarName());
197 Integer writer = writerMap.get(i.getVarName());
198 if ((value != null)&&(writer != null)) {
199 if (!value.equals(i.getValue())&&!writer.equals(i.getAppNum())) {
200 // We have different values and different writers
201 errorMessage = createErrorMessage(i, valueMap, writerMap);
211 boolean updateTheOutSet(Node parentNode, Node currentNode) {
212 HashMap<Transition, ArrayList<NameValuePair>> setSets = parentNode.getOutgoingEdges().get(currentNode).getSetSetMap();
213 HashSet<String> updatedVarNames = new HashSet<String>();
214 Edge currentEdge = parentNode.getOutgoingEdges().get(currentNode);
215 HashMap<String, Integer> lastWriter = currentEdge.getLastWriter();
216 HashMap<String, String> lastValue = currentEdge.getLastValue();
217 HashMap<String, Integer> outSetVarMap = new HashMap<String, Integer>();
218 boolean isChanged = false;
220 for (Map.Entry mapElement : setSets.entrySet()) {
221 ArrayList<NameValuePair> setSet = (ArrayList<NameValuePair>)mapElement.getValue();
223 for (int i = 0;i < setSet.size();i++) {
224 updatedVarNames.add(setSet.get(i).getVarName());
229 for (NameValuePair i : parentNode.getOutSet()) {
230 outSetVarMap.put(i.getVarName(), i.getAppNum());
231 if (!updatedVarNames.contains(i.getVarName()))
232 isChanged |= currentNode.getOutSet().add(i);
236 for (Map.Entry mapElement : setSets.entrySet()) {
237 ArrayList<NameValuePair> setSet = (ArrayList<NameValuePair>)mapElement.getValue();
239 for (int i = 0;i < setSet.size();i++) {
240 String varName = setSet.get(i).getVarName();
241 Integer writer = lastWriter.get(varName);
242 String value = lastValue.get(varName);
244 if (setSet.get(i).getAppNum().equals(writer)
245 && setSet.get(i).getValue().equals(value)) {
246 if (outSetVarMap.containsKey(varName)) {
247 Integer hashCode = outSetVarMap.get(varName).hashCode() * 31 +
249 currentNode.getOutSet().remove(hashCode);
251 isChanged |= currentNode.getOutSet().add(setSet.get(i));
259 void updateTheEdge(Node currentNode, Transition transition) {
260 if (parentNode.getOutgoingEdges().containsKey(currentNode)) {
261 Edge currentEdge = parentNode.getOutgoingEdges().get(currentNode);
262 if (currentEdge.getSetSetMap().containsKey(transition)) { // Update the transition
264 currentEdge.getSetSetMap().put(transition, tempSetSet);
266 currentEdge.getSetSetMap().get(transition).addAll(tempSetSet);
267 } else { // Add a new transition
268 currentEdge.getSetSetMap().put(transition, tempSetSet);
271 parentNode.getOutgoingEdges().put(currentNode, new Edge(parentNode, currentNode));
272 Edge currentEdge = parentNode.getOutgoingEdges().get(currentNode);
273 currentEdge.getSetSetMap().put(transition, tempSetSet);
276 // Update the last writer and last value for this edge for each varName
277 Edge currentEdge = parentNode.getOutgoingEdges().get(currentNode);
278 ArrayList<NameValuePair> setSet = currentEdge.getSetSetMap().get(transition);
279 for (int i = 0;i < setSet.size();i++) {
280 NameValuePair nameValuePair = setSet.get(i);
281 currentEdge.getLastWriter().put(nameValuePair.getVarName(), nameValuePair.getAppNum());
282 currentEdge.getLastValue().put(nameValuePair.getVarName(), nameValuePair.getValue());
290 HashSet<Node> predecessors = new HashSet<Node>();
291 HashSet<Node> successors = new HashSet<Node>();
292 HashSet<NameValuePair> outSet = new HashSet<NameValuePair>();
293 HashMap<Node, Edge> outgoingEdges = new HashMap<Node, Edge>();
303 HashSet<Node> getPredecessors() {
307 HashSet<Node> getSuccessors() {
311 HashSet<NameValuePair> getOutSet() {
315 HashMap<Node, Edge> getOutgoingEdges() {
316 return outgoingEdges;
321 Node source, destination;
322 HashMap<String, Integer> lastWriter = new HashMap<String, Integer>();
323 HashMap<String, String> lastValue = new HashMap<String, String>();
324 HashMap<Transition, ArrayList<NameValuePair>> setSetMap = new HashMap<Transition, ArrayList<NameValuePair>>();
326 Edge(Node source, Node destination) {
327 this.source = source;
328 this.destination = destination;
335 Node getDestination() {
339 HashMap<Transition, ArrayList<NameValuePair>> getSetSetMap() {
343 HashMap<String, Integer> getLastWriter() {
347 HashMap<String, String> getLastValue() {
352 static class NameValuePair {
358 NameValuePair(Integer appNum, String value, String varName, boolean isManual) {
359 this.appNum = appNum;
361 this.varName = varName;
362 this.isManual = isManual;
365 void setAppNum(Integer appNum) {
366 this.appNum = appNum;
369 void setValue(String value) {
373 void setVarName(String varName) {
374 this.varName = varName;
377 void setIsManual(String varName) {
378 this.isManual = isManual;
381 Integer getAppNum() {
389 String getVarName() {
393 boolean getIsManual() {
398 public boolean equals(Object o) {
399 if (o instanceof NameValuePair) {
400 NameValuePair other = (NameValuePair) o;
401 if (varName.equals(other.getVarName()))
402 return appNum.equals(other.getAppNum());
408 public int hashCode() {
409 return appNum.hashCode() * 31 + varName.hashCode();
414 public void stateRestored(Search search) {
415 id = search.getStateId();
416 depth = search.getDepth();
417 operation = "restored";
420 out.println("The state is restored to state with id: "+id+", depth: "+depth);
422 // Update the parent node
423 if (nodes.containsKey(id)) {
424 parentNode = nodes.get(id);
426 parentNode = new Node(id);
431 public void searchStarted(Search search) {
432 out.println("----------------------------------- search started");
437 public void stateAdvanced(Search search) {
438 String theEnd = null;
439 Transition transition = search.getTransition();
440 id = search.getStateId();
441 depth = search.getDepth();
442 operation = "forward";
444 // Add the node to the list of nodes
445 if (nodes.get(id) == null)
446 nodes.put(id, new Node(id));
448 Node currentNode = nodes.get(id);
450 // Update the edge based on the current transition
451 updateTheEdge(currentNode, transition);
453 // Reset the temporary variables and flags
454 tempSetSet = new ArrayList<NameValuePair>();
457 // Check for the conflict in this transition
458 conflictFound = checkForConflict(parentNode, currentNode, transition);
460 if (search.isNewState()) {
466 if (search.isEndState()) {
467 out.println("This is the last state!");
471 out.println("The state is forwarded to state with id: "+id+", depth: "+depth+" which is "+detail+" state: "+"% "+theEnd);
473 // Updating the predecessors for this node
474 // Check if parent node is already in successors of the current node or not
475 if (!(currentNode.getPredecessors().contains(parentNode)))
476 currentNode.getPredecessors().add(parentNode);
478 // Update the successors for this node
479 // Check if current node is already in successors of the parent node or not
480 if (!(parentNode.getSuccessors().contains(currentNode)))
481 parentNode.getSuccessors().add(currentNode);
483 // Update the outset of the current node and check if it is changed or not to propagate the change
484 boolean isChanged = updateTheOutSet(parentNode, currentNode);
486 // Check if the outSet of this state has changed, update all of its successors' sets if any
488 for (Node node : currentNode.getSuccessors()) {
489 HashMap<Transition, ArrayList<NameValuePair>> setSets = currentNode.getOutgoingEdges().get(node).getSetSetMap();
490 for (Map.Entry mapElement : setSets.entrySet()) {
491 Transition currentTransition = (Transition)mapElement.getKey();
492 conflictFound = conflictFound || checkForConflict(currentNode, node, currentTransition);
495 conflictFound = conflictFound || propagateTheChange(currentNode);
497 // Update the parent node
498 if (nodes.containsKey(id)) {
499 parentNode = nodes.get(id);
501 parentNode = new Node(id);
506 public void stateBacktracked(Search search) {
507 id = search.getStateId();
508 depth = search.getDepth();
509 operation = "backtrack";
512 out.println("The state is backtracked to state with id: "+id+", depth: "+depth);
514 // Update the parent node
515 if (nodes.containsKey(id)) {
516 parentNode = nodes.get(id);
518 parentNode = new Node(id);
523 public void searchFinished(Search search) {
524 out.println("----------------------------------- search finished");
527 private String getValue(ThreadInfo ti, Instruction inst, byte type) {
531 frame = ti.getTopFrame();
533 if ((inst instanceof JVMLocalVariableInstruction) ||
534 (inst instanceof JVMFieldInstruction))
536 if (frame.getTopPos() < 0)
540 hi = frame.getTopPos() >= 1 ? frame.peek(1) : 0;
542 return(decodeValue(type, lo, hi));
545 if (inst instanceof JVMArrayElementInstruction)
546 return(getArrayValue(ti, type));
551 private final static String decodeValue(byte type, int lo, int hi) {
553 case Types.T_ARRAY: return(null);
554 case Types.T_VOID: return(null);
556 case Types.T_BOOLEAN: return(String.valueOf(Types.intToBoolean(lo)));
557 case Types.T_BYTE: return(String.valueOf(lo));
558 case Types.T_CHAR: return(String.valueOf((char) lo));
559 case Types.T_DOUBLE: return(String.valueOf(Types.intsToDouble(lo, hi)));
560 case Types.T_FLOAT: return(String.valueOf(Types.intToFloat(lo)));
561 case Types.T_INT: return(String.valueOf(lo));
562 case Types.T_LONG: return(String.valueOf(Types.intsToLong(lo, hi)));
563 case Types.T_SHORT: return(String.valueOf(lo));
565 case Types.T_REFERENCE:
566 ElementInfo ei = VM.getVM().getHeap().get(lo);
570 ClassInfo ci = ei.getClassInfo();
574 if (ci.getName().equals("java.lang.String"))
575 return('"' + ei.asString() + '"');
577 return(ei.toString());
580 System.err.println("Unknown type: " + type);
585 private String getArrayValue(ThreadInfo ti, byte type) {
589 frame = ti.getTopFrame();
591 hi = frame.getTopPos() >= 1 ? frame.peek(1) : 0;
593 return(decodeValue(type, lo, hi));
596 private byte getType(ThreadInfo ti, Instruction inst) {
601 frame = ti.getTopFrame();
602 if ((frame.getTopPos() >= 0) && (frame.isOperandRef())) {
603 return (Types.T_REFERENCE);
608 if (inst instanceof JVMLocalVariableInstruction) {
609 type = ((JVMLocalVariableInstruction) inst).getLocalVariableType();
610 } else if (inst instanceof JVMFieldInstruction){
611 fi = ((JVMFieldInstruction) inst).getFieldInfo();
615 if (inst instanceof JVMArrayElementInstruction) {
616 return (getTypeFromInstruction(inst));
620 return (Types.T_VOID);
623 return (decodeType(type));
626 private final static byte getTypeFromInstruction(Instruction inst) {
627 if (inst instanceof JVMArrayElementInstruction)
628 return(getTypeFromInstruction((JVMArrayElementInstruction) inst));
630 return(Types.T_VOID);
633 private final static byte decodeType(String type) {
634 if (type.charAt(0) == '?'){
635 return(Types.T_REFERENCE);
637 return Types.getBuiltinType(type);
641 // Find the variable writer
642 // It should be one of the apps listed in the .jpf file
643 private String getWriter(List<StackFrame> sfList, HashSet<String> writerSet) {
644 // Start looking from the top of the stack backward
645 for(int i=sfList.size()-1; i>=0; i--) {
646 MethodInfo mi = sfList.get(i).getMethodInfo();
647 if(!mi.isJPFInternal()) {
648 String method = mi.getStackTraceName();
649 // Check against the writers in the writerSet
650 for(String writer : writerSet) {
651 if (method.contains(writer)) {
661 private void writeWriterAndValue(String writer, String value, String var) {
662 // Update the temporary Set set.
663 NameValuePair temp = new NameValuePair(1, value, var, manual);
664 if (writer.equals("App2"))
665 temp = new NameValuePair(2, value, var, manual);
667 tempSetSet.add(temp);
671 public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
673 if (System.currentTimeMillis() - startTime > timeout) {
674 StringBuilder sbTimeOut = new StringBuilder();
675 sbTimeOut.append("Execution timeout: " + (timeout / (60 * 1000)) + " minutes have passed!");
676 Instruction nextIns = ti.createAndThrowException("java.lang.RuntimeException", sbTimeOut.toString());
677 ti.setNextPC(nextIns);
682 StringBuilder sb = new StringBuilder();
683 sb.append(errorMessage);
684 Instruction nextIns = ti.createAndThrowException("java.lang.RuntimeException", sb.toString());
685 ti.setNextPC(nextIns);
687 if (conflictSet.contains(LOCATION_VAR)) {
688 MethodInfo mi = executedInsn.getMethodInfo();
689 // Find the last load before return and get the value here
690 if (mi.getName().equals(SET_LOCATION_METHOD) &&
691 executedInsn instanceof ALOAD && nextInsn instanceof ARETURN) {
692 byte type = getType(ti, executedInsn);
693 String value = getValue(ti, executedInsn, type);
695 // Extract the writer app name
696 ClassInfo ci = mi.getClassInfo();
697 String writer = ci.getName();
699 // Update the temporary Set set.
700 writeWriterAndValue(writer, value, LOCATION_VAR);
703 if (executedInsn instanceof WriteInstruction) {
704 String varId = ((WriteInstruction) executedInsn).getFieldInfo().getFullName();
706 for (String var : conflictSet) {
707 if (varId.contains(var)) {
709 byte type = getType(ti, executedInsn);
710 String value = getValue(ti, executedInsn, type);
711 String writer = getWriter(ti.getStack(), appSet);
712 // Just return if the writer is not one of the listed apps in the .jpf file
716 if (getWriter(ti.getStack(), manualSet) != null)
719 // Update the temporary Set set.
720 writeWriterAndValue(writer, value, var);