Bug 1182516 - Add Chaos Mode environment variable MOZ_CHAOSMODE. r=roc

mfbt/ChaosMode.cpp

@@ -7,9 +7,11 @@
 #include "mozilla/ChaosMode.h"
 
 namespace mozilla {
+
 namespace detail {
 
 Atomic<uint32_t> gChaosModeCounter(0);
+ChaosFeature gChaosFeatures = None;
 
 } /* namespace detail */
 } /* namespace mozilla */

mfbt/ChaosMode.h

@@ -15,19 +15,7 @@
 
 namespace mozilla {
 
-namespace detail {
+enum ChaosFeature {
-extern MFBT_DATA Atomic<uint32_t> gChaosModeCounter;
-} // namespace detail
-
-/**
- * When "chaos mode" is activated, code that makes implicitly nondeterministic
- * choices is encouraged to make random and extreme choices, to test more
- * code paths and uncover bugs.
- */
-class ChaosMode
-{
-public:
-  enum ChaosFeature {
   None = 0x0,
   // Altering thread scheduling.
   ThreadScheduling = 0x1,
@@ -40,19 +28,32 @@ public:
   // Iterate over hash tables in random order.
   HashTableIteration = 0x10,
   Any = 0xffffffff,
-  };
+};
 
-private:
+namespace detail {
-  // Change this to any non-None value to activate ChaosMode.
+extern MFBT_DATA Atomic<uint32_t> gChaosModeCounter;
-  static const ChaosFeature sChaosFeatures = None;
+extern MFBT_DATA ChaosFeature gChaosFeatures;
+} // namespace detail
 
+/**
+ * When "chaos mode" is activated, code that makes implicitly nondeterministic
+ * choices is encouraged to make random and extreme choices, to test more
+ * code paths and uncover bugs.
+ */
+class ChaosMode
+{
 public:
+  static void SetChaosFeature(ChaosFeature aChaosFeature)
+  {
+    detail::gChaosFeatures = aChaosFeature;
+  }
+
   static bool isActive(ChaosFeature aFeature)
   {
     if (detail::gChaosModeCounter > 0) {
       return true;
     }
-    return sChaosFeatures & aFeature;
+    return detail::gChaosFeatures & aFeature;
   }
 
   /**

netwerk/base/nsSocketTransportService2.cpp

@@ -275,7 +275,7 @@ nsSocketTransportService::AddToPollList(SocketContext *sock)
     }
     
     uint32_t newSocketIndex = mActiveCount;
-    if (ChaosMode::isActive(ChaosMode::NetworkScheduling)) {
+    if (ChaosMode::isActive(ChaosFeature::NetworkScheduling)) {
       newSocketIndex = ChaosMode::randomUint32LessThan(mActiveCount + 1);
       PodMove(mActiveList + newSocketIndex + 1, mActiveList + newSocketIndex,
               mActiveCount - newSocketIndex);

netwerk/protocol/http/nsHttpConnection.cpp

@@ -1626,7 +1626,7 @@ nsHttpConnection::OnWriteSegment(char *buf,
         return NS_ERROR_FAILURE; // stop iterating
     }
 
-    if (ChaosMode::isActive(ChaosMode::IOAmounts) &&
+    if (ChaosMode::isActive(ChaosFeature::IOAmounts) &&
         ChaosMode::randomUint32LessThan(2)) {
         // read 1...count bytes
         count = ChaosMode::randomUint32LessThan(count) + 1;

netwerk/protocol/http/nsHttpConnectionMgr.cpp

@@ -56,7 +56,7 @@ InsertTransactionSorted(nsTArray<nsHttpTransaction*> &pendingQ, nsHttpTransactio
     for (int32_t i=pendingQ.Length()-1; i>=0; --i) {
         nsHttpTransaction *t = pendingQ[i];
         if (trans->Priority() >= t->Priority()) {
-	  if (ChaosMode::isActive(ChaosMode::NetworkScheduling)) {
+	  if (ChaosMode::isActive(ChaosFeature::NetworkScheduling)) {
                 int32_t samePriorityCount;
                 for (samePriorityCount = 0; i - samePriorityCount >= 0; ++samePriorityCount) {
                     if (pendingQ[i - samePriorityCount]->Priority() != trans->Priority()) {

toolkit/xre/nsAppRunner.cpp

@@ -3123,7 +3123,17 @@ XREMain::XRE_mainInit(bool* aExitFlag)
 
   StartupTimeline::Record(StartupTimeline::MAIN);
 
-  if (ChaosMode::isActive(ChaosMode::Any)) {
+  if (PR_GetEnv("MOZ_CHAOSMODE")) {
+    ChaosFeature feature = ChaosFeature::Any;
+    long featureInt = strtol(PR_GetEnv("MOZ_CHAOSMODE"), nullptr, 16);
+    if (featureInt) {
+      // NOTE: MOZ_CHAOSMODE=0 or a non-hex value maps to Any feature.
+      feature = static_cast<ChaosFeature>(featureInt);
+    }
+    ChaosMode::SetChaosFeature(feature);
+  }
+
+  if (ChaosMode::isActive(ChaosFeature::Any)) {
     printf_stderr("*** You are running in chaos test mode. See ChaosMode.h. ***\n");
   }
 

xpcom/threads/TimerThread.cpp

@@ -236,7 +236,7 @@ TimerThread::Run()
     if (mSleeping) {
       // Sleep for 0.1 seconds while not firing timers.
       uint32_t milliseconds = 100;
-      if (ChaosMode::isActive(ChaosMode::TimerScheduling)) {
+      if (ChaosMode::isActive(ChaosFeature::TimerScheduling)) {
         milliseconds = ChaosMode::randomUint32LessThan(200);
       }
       waitFor = PR_MillisecondsToInterval(milliseconds);
@@ -320,7 +320,7 @@ TimerThread::Run()
         // interval is so small we should not wait at all).
         double microseconds = (timeout - now).ToMilliseconds() * 1000;
 
-        if (ChaosMode::isActive(ChaosMode::TimerScheduling)) {
+        if (ChaosMode::isActive(ChaosFeature::TimerScheduling)) {
           // The mean value of sFractions must be 1 to ensure that
           // the average of a long sequence of timeouts converges to the
           // actual sum of their times.

xpcom/threads/nsEventQueue.cpp

@@ -95,7 +95,7 @@ nsEventQueue::PutEvent(already_AddRefed<nsIRunnable>&& aRunnable)
   // Avoid calling AddRef+Release while holding our monitor.
   nsCOMPtr<nsIRunnable> event(aRunnable);
 
-  if (ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
+  if (ChaosMode::isActive(ChaosFeature::ThreadScheduling)) {
     // With probability 0.5, yield so other threads have a chance to
     // dispatch events to this queue first.
     if (ChaosMode::randomUint32LessThan(2)) {

xpcom/threads/nsThread.cpp

@@ -284,7 +284,7 @@ private:
 static void
 SetupCurrentThreadForChaosMode()
 {
-  if (!ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
+  if (!ChaosMode::isActive(ChaosFeature::ThreadScheduling)) {
     return;
   }
 
@@ -926,7 +926,7 @@ nsThread::SetPriority(int32_t aPriority)
     pri = PR_PRIORITY_NORMAL;
   }
   // If chaos mode is active, retain the randomly chosen priority
-  if (!ChaosMode::isActive(ChaosMode::ThreadScheduling)) {
+  if (!ChaosMode::isActive(ChaosFeature::ThreadScheduling)) {
     PR_SetThreadPriority(mThread, pri);
   }