Adding standard UNIX/POSIX signals listener. GNSS-SDR now can be safely stopped using CTL+C

src/core/receiver/control_thread.cc

@@ -78,9 +78,49 @@ namespace wht = std;
 extern Concurrent_Map<Gps_Acq_Assist> global_gps_acq_assist_map;
 extern Concurrent_Queue<Gps_Acq_Assist> global_gps_acq_assist_queue;
 
+ControlThread* ControlThread::me=nullptr;
+
+
+/**
+ * \brief Callback function for handling signals.
+ * \param	sig	identifier of signal
+ */
+void ControlThread::handle_signal(int sig)
+{
+    if (sig == SIGINT)
+        {
+            std::cout << "Stopping GNSS-SDR via SIGINT...\n";
+
+            ControlThread::me->control_queue_->push(pmt::make_any(command_event_make(200, 0)));
+            ControlThread::me->stop_ = true;
+
+            /* Reset signal handling to default behavior */
+            signal(SIGINT, SIG_DFL);
+        }
+    else if (sig == SIGHUP)
+        {
+
+        	std::cout << "Debug: received SIGHUP signal\n";
+            //std::cout << "Debug: reloading daemon config file ...\n";
+            //todo
+        }
+    else if (sig == SIGCHLD)
+        {
+            std::cout << "Debug: received SIGCHLD signal\n";
+            //todo
+        }
+}
+
 
 ControlThread::ControlThread()
 {
+
+	ControlThread::me=this;
+
+    /* the class will handle two signals */
+    signal(SIGINT, ControlThread::handle_signal);
+    signal(SIGHUP, ControlThread::handle_signal);
+
     if (FLAGS_c == "-")
         {
             configuration_ = std::make_shared<FileConfiguration>(FLAGS_config_file);

src/core/receiver/control_thread.h

@@ -37,6 +37,7 @@
 #include <typeinfo>  // for std::type_info, typeid
 #include <utility>   // for pair
 #include <vector>    // for vector
+#include <csignal>
 
 #ifdef ENABLE_FPGA
 #include <boost/thread.hpp>  // for boost::thread
@@ -54,6 +55,7 @@ class ConfigurationInterface;
 class GNSSFlowgraph;
 class Gnss_Satellite;
 
+
 /*!
  * \brief This class represents the main thread of the application, so the name is ControlThread.
  * This is the GNSS Receiver Control Plane: it connects the flowgraph, starts running it,
@@ -63,6 +65,8 @@ class Gnss_Satellite;
 class ControlThread
 {
 public:
+
+    static ControlThread* me;
     /*!
      * \brief Default constructor
      */
@@ -122,6 +126,9 @@ public:
     }
 
 private:
+
+    static void handle_signal(int sig);
+
     void init();
 
     void apply_action(unsigned int what);