Rework SignalHandler for more compact code

Rather than have special cases all over, I have abstracted the code so it's
easier to deal with.

The pre-generated strings for the "last gasp" output for SEGV, etc has been
changed to include the entire string so it only uses one write() call.

Moved SIGHUP handling in the logserver to use the common SignalHandler class
code.

Added SIGBUS, SIGFPE, SIGILL to our standard supported signals, treating them
the same as SIGSEGV.

mythtv/libs/libmythbase/loggingserver.cpp

@@ -95,12 +95,6 @@ static QAtomicInt                   msgsSinceHeartbeat;
 #define TIMESTAMP_MAX 30
 #define MAX_STRING_LENGTH (LOGLINE_MAX+120)
 
-#ifndef _WIN32
-static int sighupFd[2];
-void logSighup(int signum);
-#endif
-
-
 /// \brief LoggerBase class constructor.  Adds the new logger instance to the
 ///        loggerMap.
 /// \param string a C-string of the handle for this instance (NULL if unused)
@@ -758,15 +752,18 @@ void DBLoggerThread::stop(void)
 
 
 #ifndef _WIN32
-/// \brief UNIX-side SIGHUP signal handler.  Hand it off to the Qt-size via
-///        a socketpair so Qt code can safely be used.
+/// \brief Signal handler for SIGHUP.  This passes it to the LogForwardThread
+///        for processing.
 
-void logSighup(int signum)
+void logSigHup(void)
 {
-    (void)signum;
-    char a = 1;
-    int ret = ::write(sighupFd[0], &a, sizeof(a));
-    (void)ret;
+    if (!logForwardThread)
+        return;
+
+    // This will be running in the thread that's used by SignalHandler
+    // Emit the signal which is connected to a slot that runs in the actual
+    // handling thread.
+    emit logForwardThread->incomingSigHup();
 }
 #endif
 
@@ -1064,7 +1061,7 @@ void DatabaseLogger::receivedMessage(const QList<QByteArray> &msg)
 /// \brief LogForwardThread constructor.
 LogForwardThread::LogForwardThread() :
     MThread("LogForward"), m_aborted(false), m_zmqContext(NULL),
-    m_zmqPubSock(NULL), m_sighupNotifier(NULL), m_shutdownTimer(NULL)
+    m_zmqPubSock(NULL), m_shutdownTimer(NULL)
 {
     moveToThread(qthread());
 }
@@ -1083,25 +1080,8 @@ void LogForwardThread::run(void)
 {
     RunProlog();
 
-#ifndef _WIN32
-    if (::socketpair(AF_UNIX, SOCK_STREAM, 0, sighupFd))
-    {
-        LOG(VB_GENERAL, LOG_ERR, "Couldn't create HUP socketpair");
-        qApp->quit();
-    }
-    m_sighupNotifier = new QSocketNotifier(sighupFd[1], QSocketNotifier::Read,
-                                           this);
-    connect(m_sighupNotifier, SIGNAL(activated(int)),
-            this, SLOT(handleSigHup()));
-
-    /* Setup SIGHUP */
-    LOG(VB_GENERAL, LOG_INFO, "Setup SIGHUP handler");
-    struct sigaction sa;
-    sa.sa_handler = logSighup;
-    sigemptyset( &sa.sa_mask );
-    sa.sa_flags = SA_RESTART;
-    sigaction( SIGHUP, &sa, NULL );
-#endif
+    connect(this, SIGNAL(incomingSigHup(void)), this, SLOT(handleSigHup(void)),
+            Qt::QueuedConnection);
 
     qRegisterMetaType<QList<QByteArray> >("QList<QByteArray>");
 
@@ -1151,19 +1131,6 @@ void LogForwardThread::run(void)
         expireClients();
     }
 
-    delete m_sighupNotifier;
-
-#ifndef _WIN32
-    ::close(sighupFd[0]);
-    ::close(sighupFd[1]);
-
-    /* Tear down SIGHUP */
-    sa.sa_handler = SIG_DFL;
-    sigemptyset( &sa.sa_mask );
-    sa.sa_flags = SA_RESTART;
-    sigaction( SIGHUP, &sa, NULL );
-#endif
-
     m_zmqPubSock->setLinger(0);
     m_zmqPubSock->close();
 
@@ -1258,12 +1225,6 @@ void LogForwardThread::expireClients(void)
 void LogForwardThread::handleSigHup(void)
 {
 #ifndef _WIN32
-    m_sighupNotifier->setEnabled(false);
-
-    char tmp;
-    int ret = ::read(sighupFd[1], &tmp, sizeof(tmp));
-    (void)ret;
-
     LOG(VB_GENERAL, LOG_INFO, "SIGHUP received, rolling log files.");
 
     /* SIGHUP was sent.  Close and reopen debug logfiles */
@@ -1273,8 +1234,6 @@ void LogForwardThread::handleSigHup(void)
     {
         it.value()->reopen();
     }
-
-    m_sighupNotifier->setEnabled(true);
 #endif
 }
 

mythtv/libs/libmythbase/loggingserver.h

@@ -168,7 +168,7 @@ class LogForwardThread : public QObject, public MThread
 {
     Q_OBJECT
 
-    friend void logSighup(int signum);
+    friend void logSigHup(void);
   public:
     LogForwardThread();
     ~LogForwardThread();
@@ -180,14 +180,13 @@ class LogForwardThread : public QObject, public MThread
     nzmqt::ZMQContext *m_zmqContext; ///< ZeroMQ context
     nzmqt::ZMQSocket *m_zmqPubSock;  ///< ZeroMQ publishing socket
 
-    QSocketNotifier *m_sighupNotifier;  ///< Notifier to synchronize to UNIX
-                                        ///  signal SIGHUP safely
-
     MythSignalingTimer *m_shutdownTimer;    ///< 5 min timer to shut down if no
                                             /// clients
 
     void forwardMessage(LogMessage *msg);
     void expireClients(void);
+  signals:
+    void incomingSigHup(void);
   protected slots:
     void handleSigHup(void);
     void shutdownTimerExpired(void);
@@ -243,6 +242,10 @@ class DBLoggerThread : public MThread
 
 extern LogServerThread *logServerThread;
 
+#ifndef _WIN32
+MBASE_PUBLIC void logSigHup(void);
+#endif
+
 #endif
 
 /*

mythtv/libs/libmythbase/mythversion.h

@@ -12,7 +12,7 @@
 /// Update this whenever the plug-in API changes.
 /// Including changes in the libmythbase, libmyth, libmythtv, libmythav* and
 /// libmythui class methods used by plug-ins.
-#define MYTH_BINARY_VERSION "0.26.20120617-1"
+#define MYTH_BINARY_VERSION "0.26.20120620-1"
 
 /** \brief Increment this whenever the MythTV network protocol changes.
  *