- Fix arm compiler warning. GCC treats chars as unsigned in this arch.

- Fix race condition in json metrics.

lib/src/common/enb_events.cc

@@ -94,7 +94,8 @@ static std::string escape_string(const std::string& s)
         fmt::format_to(buff, "\\t");
         break;
       default:
-        if ('\x00' <= c && c <= '\x1f') {
+        // Cast to signed char for machines that treat chars as an unsigned type.
+        if ((signed char)c >= '\x00' && (signed char)c <= '\x1f') {
           fmt::format_to(buff, "\\u{:04x}", c);
         } else {
           buff.push_back(c);

srsenb/hdr/metrics_json.h

@@ -26,10 +26,9 @@ namespace srsenb {
 class metrics_json : public srsran::metrics_listener<enb_metrics_t>
 {
 public:
-  metrics_json(srslog::log_channel& c) : log_c(c) {}
+  metrics_json(srslog::log_channel& c, enb_metrics_interface* enb_) : log_c(c), enb(enb_) {}
 
   void set_metrics(const enb_metrics_t& m, const uint32_t period_usec) override;
-  void set_handle(enb_metrics_interface* enb_);
   void stop() override {}
 
 private:

srsenb/src/main.cc

@@ -607,10 +607,9 @@ int main(int argc, char* argv[])
     metrics_file.set_handle(enb.get());
   }
 
-  srsenb::metrics_json json_metrics(json_channel);
+  srsenb::metrics_json json_metrics(json_channel, enb.get());
   if (args.general.report_json_enable) {
     metricshub.add_listener(&json_metrics);
-    json_metrics.set_handle(enb.get());
   }
 
   // create input thread

srsenb/src/metrics_json.cc

@@ -15,11 +15,6 @@
 
 using namespace srsenb;
 
-void metrics_json::set_handle(enb_metrics_interface* enb_)
-{
-  enb = enb_;
-}
-
 namespace {
 
 /// Bearer container metrics.