add signal handlers; closes #564

src/SignalWatcher.cc

@@ -0,0 +1,63 @@
+#include "SignalWatcher.hh"
+
+#include <event2/event.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <phosg/Random.hh>
+#include <phosg/Strings.hh>
+
+#include "ReceiveCommands.hh"
+#include "SendCommands.hh"
+#include "ServerState.hh"
+#include "StaticGameData.hh"
+
+using namespace std;
+
+SignalWatcher::SignalWatcher(shared_ptr<ServerState> state)
+    : log("[SignalWatcher] "),
+      state(state),
+      sigusr1_event(evsignal_new(this->state->base.get(), SIGUSR1, &SignalWatcher::dispatch_on_signal, this), event_free),
+      sigusr2_event(evsignal_new(this->state->base.get(), SIGUSR2, &SignalWatcher::dispatch_on_signal, this), event_free) {
+  event_add(this->sigusr1_event.get(), nullptr);
+  event_add(this->sigusr2_event.get(), nullptr);
+}
+
+void SignalWatcher::dispatch_on_signal(evutil_socket_t signal, short what, void* ctx) {
+  if (what != EV_SIGNAL) {
+    throw logic_error("dispatch_on_signal called for non-signal event");
+  }
+  reinterpret_cast<SignalWatcher*>(ctx)->on_signal(signal);
+}
+
+void SignalWatcher::on_signal(int signum) {
+  switch (signum) {
+    case SIGUSR1:
+      this->log.info("Received SIGUSR1; reloading config.json");
+      this->state->forward_to_event_thread([s = this->state]() {
+        try {
+          s->load_config_early();
+          s->load_config_late();
+          fprintf(stderr, "Configuration update complete\n");
+        } catch (const exception& e) {
+          fprintf(stderr, "FAILED: %s\n", e.what());
+          fprintf(stderr, "Some configuration may have been reloaded. Fix the underlying issue and try again.\n");
+        }
+      });
+      break;
+    case SIGUSR2:
+      this->log.info("Received SIGUSR2; reloading config.json and all dependencies");
+      this->state->forward_to_event_thread([s = this->state]() {
+        try {
+          s->load_all();
+          fprintf(stderr, "Configuration update complete\n");
+        } catch (const exception& e) {
+          fprintf(stderr, "FAILED: %s\n", e.what());
+          fprintf(stderr, "Some configuration may have been reloaded. Fix the underlying issue and try again.\n");
+        }
+      });
+      break;
+    default:
+      this->log.warning("Unknown signal received: %d", signum);
+  }
+}