Changes: Qt-styled Unix signal handling added to MBooster. Fixes the issue where booster-m

is not killed when launcher dies.

RevBy: Alexey Shilov, Antti Kervinen

src/launcher/booster.cpp

@@ -228,7 +228,7 @@ void Booster::renameProcess(int parentArgc, char** parentArgv)
         }
     }
 
-    // Set the process name using prctl, killall and top use it
+    // Set the process name using prctl, 'killall' and 'top' use it
     if ( prctl(PR_SET_NAME, basename(newProcessName)) == -1 )
         Logger::logError("Booster: on set new process name: %s ", strerror(errno));
 

src/launcher/daemon.cpp

@@ -73,7 +73,7 @@ Daemon::Daemon(int & argc, char * argv[]) :
 
     if (pipe(m_pipefd) == -1)
     {
-        Logger::logErrorAndDie(EXIT_FAILURE, "Daemon: Creating a pipe failed!!!\n");
+        Logger::logErrorAndDie(EXIT_FAILURE, "Daemon: Creating a pipe failed!\n");
     }
 
     // Daemonize if desired

src/launcher/mbooster.cpp

@@ -23,6 +23,7 @@
 
 #include <QtConcurrentRun>
 #include <MApplication>
+#include <sys/socket.h>
 
 #ifdef HAVE_MCOMPONENTCACHE
 #include <mcomponentcache.h>
@@ -31,6 +32,69 @@
 const string MBooster::m_socketId  = "/tmp/boostm";
 const string MBooster::m_temporaryProcessName = "booster-m";
 int MBooster::m_ProcessID = 0;
+int MBooster::m_sighupFd[2];
+struct sigaction MBooster::m_oldSigAction;
+
+MBooster::MBooster()
+{
+    // Install signals handler e.g. to exit cleanly if launcher dies.
+    // This is a problem because MBooster runs a Qt event loop.
+    setupUnixSignalHandlers();
+
+    // Create socket pair for SIGTERM
+    if (::socketpair(AF_UNIX, SOCK_STREAM, 0, m_sighupFd))
+    {
+       Logger::logError("Couldn't create HUP socketpair");
+    }
+    else
+    {
+        // Install a socket notifier on the socket
+        m_snHup.reset(new QSocketNotifier(m_sighupFd[1], QSocketNotifier::Read, this));
+        connect(m_snHup.get(), SIGNAL(activated(int)), this, SLOT(handleSigHup()));
+    }
+}
+
+//
+// All this signal handling code is taken from Qt's Best Practices:
+// http://doc.qt.nokia.com/latest/unix-signals.html
+//
+
+void MBooster::hupSignalHandler(int)
+{
+    char a = 1;
+    ::write(m_sighupFd[0], &a, sizeof(a));
+}
+
+void MBooster::handleSigHup()
+{
+    ::exit(EXIT_SUCCESS);
+}
+
+bool MBooster::setupUnixSignalHandlers()
+{
+    struct sigaction hup;
+
+    hup.sa_handler = MBooster::hupSignalHandler;
+    sigemptyset(&hup.sa_mask);
+    hup.sa_flags |= SA_RESTART;
+
+    if (sigaction(SIGHUP, &hup, &m_oldSigAction) > 0)
+    {
+        return false;
+    }
+
+    return true;
+}
+
+bool MBooster::restoreUnixSignalHandlers()
+{
+    if (sigaction(SIGHUP, &m_oldSigAction, 0) > 0)
+    {
+        return false;
+    }
+
+    return true;
+}
 
 const string & MBooster::socketId() const
 {
@@ -88,9 +152,12 @@ bool MBooster::readCommand()
     // start another thread to listen connection from invoker
     QtConcurrent::run(this, &MBooster::accept);
 
-    // run event loop so MApplication and MApplicationWindow objects can receive notifications
+    // Run event loop so MApplication and MApplicationWindow objects can receive notifications
     MApplication::exec();
 
+    // Restore signal handlers to previous values
+    restoreUnixSignalHandlers();
+
     // Receive application data from the invoker
     if(!m_conn->receiveApplicationData(m_app))
     {

src/launcher/mbooster.h

@@ -22,7 +22,12 @@
 
 #include "booster.h"
 #include <QObject>
+#include <QSocketNotifier>
+#include <tr1/memory>
 
+using std::tr1::shared_ptr;
+
+#include <signal.h>
 
 /*!
     \class MBooster
@@ -40,7 +45,7 @@ class MBooster : public QObject, public Booster
 public:
 
     //! \brief Constructor
-    MBooster() {};
+    MBooster();
 
     //! \brief Destructor
     virtual ~MBooster() {};
@@ -80,6 +85,15 @@ public:
      */
     static int processId();
 
+    //! UNIX signal handler for SIGHUP
+    static void hupSignalHandler(int unused);
+
+    //! Setup UNIX signal handlers
+    static bool setupUnixSignalHandlers();
+
+    //! Restore UNIX signal handlers to previous values
+    static bool restoreUnixSignalHandlers();
+
 protected:
 
     //! \reimp
@@ -106,12 +120,27 @@ private:
 
     void accept();
 
-#ifdef UNIT_TEST
-    friend class Ut_MBooster;
-#endif
+    //! Socket pair used to get SIGHUP
+    static int m_sighupFd[2];
+
+    //! Socket notifier used for m_sighupFd
+    shared_ptr<QSocketNotifier> m_snHup;
+
+    //! Old sigaction struct
+    static struct sigaction m_oldSigAction;
+
+private slots:
+
+    //! Qt signal handler for SIGHUP.
+    void handleSigHup();
 
 signals:
+
     void connectionAccepted();
+
+#ifdef UNIT_TEST
+    friend class Ut_MBooster;
+#endif
 };
 
 #endif // MBOOSTER_H