Cleanly exit when unable to attach a probe

src/bpftrace.cpp

@@ -64,8 +64,16 @@ int BPFtrace::run()
       std::cerr << "Code not generated for probe: " << probe.name << std::endl;
       return -1;
     }
+    try
+    {
       attached_probes.push_back(std::make_unique<AttachedProbe>(probe, func->second));
     }
+    catch (std::runtime_error e)
+    {
+      std::cerr << e.what() << std::endl;
+      return -1;
+    }
+  }
 
   // TODO wait here while script is running
   getchar();