Add signal handler to aktualizr daemon

Interrupts the main loop cleanly when a signal is caught

Signed-off-by: Laurent Bonnans <laurent.bonnans@here.com>

src/libaktualizr/primary/aktualizr.cc

@@ -7,6 +7,7 @@
 #include <sodium.h>
 
 #include "primary/events.h"
+#include "utilities/sig_handler.h"
 #include "utilities/timer.h"
 
 using std::make_shared;
@@ -83,8 +84,24 @@ bool Aktualizr::UptaneCycle() {
 std::future<void> Aktualizr::RunForever() {
   std::future<void> future = std::async(std::launch::async, [&]() {
     SendDeviceData().get();
-    while (UptaneCycle()) {
-      std::this_thread::sleep_for(std::chrono::seconds(config_.uptane.polling_sec));
+
+    bool exiting = false;
+    std::mutex exit_m;
+    std::condition_variable exit_cv;
+    SigHandler::get().start([&exit_m, &exit_cv, &exiting]() {
+      {
+        std::lock_guard<std::mutex> g(exit_m);
+        exiting = true;
+      }
+      exit_cv.notify_one();
+    });
+
+    std::unique_lock<std::mutex> l(exit_m);
+    while (true) {
+      UptaneCycle();
+      if (exit_cv.wait_for(l, std::chrono::seconds(config_.uptane.polling_sec), [&exiting] { return exiting; })) {
+        break;
+      }
     }
     uptane_client_->completeInstall();
   });