Fix some mythbackend shutdown races.

The Scheduler and AutoExpirer each keep a pointer to MainServer, but the main server was being deleted while those threads were still running with a pointer to the deleted MainServer. The scheduler doesn't have any semaphore for the variable so this shuts down that thread in the MainServer dtor. AutoExpire does mutex protect the variable, so this just adds a AutoExpirer::SetMainServer(NULL) call to the MainServer dtor for that one.

The HouseKeeping thread wasn't being explicitly stopped, but keeps a pointer to the scheduler and uses gCoreContext.. so we now tear it down before we delete the Scheduler and MythCoreContext.

The JobQueue thread wasn't being explicitly stopped, but used the gCoreContext; we now tear it down before we delete MythCoreContext.

mythtv/programs/mythbackend/main_helpers.cpp

@@ -220,8 +220,20 @@ void cleanup(void)
     signal(SIGUSR1, SIG_DFL);
 #endif
 
-    delete gCoreContext->GetScheduler();
-    gCoreContext->SetScheduler(NULL);
+    delete housekeeping;
+    housekeeping = NULL;
+
+    if (gCoreContext)
+    {
+        delete gCoreContext->GetScheduler();
+        gCoreContext->SetScheduler(NULL);
+    }
+
+    delete expirer;
+    expirer;
+
+    delete jobqueue;
+    jobqueue = NULL;
 
     delete g_pUPnp;
     g_pUPnp = NULL;

mythtv/programs/mythbackend/mainserver.cpp

@@ -125,6 +125,7 @@ class ProcessRequestThread : public QThread
   public:
     ProcessRequestThread(MainServer *ms) :
         parent(ms), socket(NULL), threadlives(false) {}
+    ~ProcessRequestThread() { killit(); wait(); }
 
     void setup(MythSocket *sock)
     {
@@ -247,6 +248,12 @@ MainServer::MainServer(bool master, int port,
 
 MainServer::~MainServer()
 {
+    // since Scheduler::SetMainServer() isn't thread-safe
+    // we need to shut down the scheduler thread before we
+    // can call SetMainServer(NULL)
+    if (m_sched)
+        m_sched->Stop();
+
     PreviewGeneratorQueue::RemoveListener(this);
     PreviewGeneratorQueue::TeardownPreviewGeneratorQueue();
 
@@ -256,6 +263,23 @@ MainServer::~MainServer()
         mythserver->deleteLater();
         mythserver = NULL;
     }
+
+    if (m_sched)
+    {
+        m_sched->Wait();
+        m_sched->SetMainServer(NULL);
+    }
+
+    if (m_expirer)
+        m_expirer->SetMainServer(NULL);
+
+    QMutexLocker locker(&threadPoolLock);
+    MythDeque<ProcessRequestThread*>::iterator it;
+    for (it = threadPool.begin(); it != threadPool.end(); ++it)
+        (*it)->killit();
+    for (it = threadPool.begin(); it != threadPool.end(); ++it)
+        delete (*it);
+    threadPool.clear();
 }
 
 void MainServer::autoexpireUpdate(void)

mythtv/programs/mythbackend/scheduler.cpp

@@ -139,6 +139,13 @@ Scheduler::~Scheduler()
     wait();
 }
 
+void Scheduler::Stop(void)
+{
+    QMutexLocker locker(&schedLock);
+    doRun = false;
+    reschedWait.wakeAll();
+}
+
 void Scheduler::SetMainServer(MainServer *ms)
 {
     m_mainServer = ms;

mythtv/programs/mythbackend/scheduler.h

@@ -37,6 +37,9 @@ class Scheduler : public QThread, public MythScheduler
               QString recordTbl = "record", Scheduler *master_sched = NULL);
     ~Scheduler();
 
+    void Stop(void);
+    void Wait(void) { QThread::wait(); }
+
     void SetExpirer(AutoExpire *autoExpirer) { m_expirer = autoExpirer; }
 
     void Reschedule(int recordid);