handle config parsing error gracefully and fix op/opc selection issue

srsue/src/main.cc

@@ -363,8 +363,14 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
     exit(1);
   }
 
+  // parse config file and handle errors gracefully
+  try {
     bpo::store(bpo::parse_config_file(conf, common), vm);
     bpo::notify(vm);
+  } catch (const boost::program_options::error& e) {
+    cerr << e.what() << endl;
+    exit(1);
+  }
 
   //Check conflicting OP/OPc options and which is being used
   if (vm.count("usim.op") && !vm["usim.op"].defaulted() &&
@@ -373,14 +379,8 @@ void parse_args(all_args_t *args, int argc, char *argv[]) {
     cout << "Conflicting options OP and OPc. Please configure either one or the other." << endl;
     exit(1);
   }
-  else
-  {
-    if(vm["usim.op"].defaulted()){
-      args->usim.using_op = true;
-    }
   else {
-      args->usim.using_op = false;
-    }
+    args->usim.using_op = vm.count("usim.op");
   }
 
   // Apply all_level to any unset layers

srsue/src/upper/usim.cc

@@ -53,8 +53,7 @@ int usim::init(usim_args_t *args, srslte::log *usim_log_)
     usim_log->console("Invalid length for K: %zu should be %d\n", args->k.length(), 32);
   }
 
-  if(args->using_op)
-  {
+  if(args->using_op) {
     if(32 == args->op.length()) {
       str_to_hex(args->op, op);
       compute_opc(k,op,opc);