add signal handlers; closes #564

CMakeLists.txt

@@ -123,6 +123,7 @@ set(SOURCES
     src/Server.cc
     src/ServerShell.cc
     src/ServerState.cc
+    src/SignalWatcher.cc
     src/StaticGameData.cc
     src/TeamIndex.cc
     src/Text.cc

README.md

@@ -148,6 +148,10 @@ There are currently no precompiled releases for Linux. To run newserv on Linux,
 
 After building newserv, edit system/config.example.json as needed **and rename it to system/config.json** (note that this step is not necessary for the precompiled releases!), set up [client patch directories](#client-patch-directories) if you're planning to play Blue Burst, then run `./newserv` in newserv's directory.
 
+The server has an interactive shell which can be used to make changes, such as managing user accounts, updating the server's configuration, managing Episode 3 tournaments, and more. Type `help` and press Enter to see all the commands.
+
+On Linux and macOS, the server also responds to SIGUSR1 and SIGUSR2. SIGUSR1 does the equivalent of the shell's `reload config` command, which reloads config.json but not any dependent files (so quests, Episode 3 maps, etc. will not be reloaded). SIGUSR2 does the equivalent of the shell's `reload all` command, which reloads everything.
+
 To use newserv in other ways (e.g. for translating data), see the end of this document.
 
 ## Client patch directories

src/Main.cc

@@ -46,6 +46,7 @@
 #include "Server.hh"
 #include "ServerShell.hh"
 #include "ServerState.hh"
+#include "SignalWatcher.hh"
 #include "StaticGameData.hh"
 #include "Text.hh"
 #include "TextIndex.hh"
@@ -2727,6 +2728,7 @@ Action a_run_server_replay_log(
 
       shared_ptr<ServerShell> shell;
       shared_ptr<ReplaySession> replay_session;
+      shared_ptr<SignalWatcher> signal_watcher;
       if (is_replay) {
         config_log.info("Starting proxy server");
         state->proxy_server = make_shared<ProxyServer>(base, state);
@@ -2842,6 +2844,11 @@ Action a_run_server_replay_log(
             state->http_server->listen(netloc.first, netloc.second);
           }
         }
+
+#ifndef PHOSG_WINDOWS
+        config_log.info("Enabling signal watcher");
+        signal_watcher = make_shared<SignalWatcher>(state);
+#endif
       }
 
       if (!state->username.empty()) {

src/ServerShell.cc

@@ -232,6 +232,7 @@ CommandDefinition c_reload(
       teams - reindex all BB teams\n\
       text-index - reload in-game text\n\
       word-select - regenerate the Word Select translation table\n\
+      all - do all of the above\n\
     Reloading will not affect items that are in use; for example, if an Episode\n\
     3 battle is in progress, it will continue to use the previous map and card\n\
     definitions. Similarly, BB clients are not forced to disconnect or reload\n\
@@ -242,7 +243,16 @@ CommandDefinition c_reload(
     +[](CommandArgs& args) {
       auto types = phosg::split(args.args, ' ');
       for (const auto& type : types) {
-        if (type == "bb-keys") {
+        if (type == "all") {
+          args.s->forward_to_event_thread([s = args.s]() {
+            try {
+              s->load_all();
+            } 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");
+            }
+          });
+        } else if (type == "bb-keys") {
           args.s->load_bb_private_keys(true);
         } else if (type == "accounts") {
           args.s->load_accounts(true);

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);
+  }
+}

src/SignalWatcher.hh

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <thread>
+
+#include <event2/event.h>
+
+#include "ServerState.hh"
+
+class SignalWatcher : public std::enable_shared_from_this<SignalWatcher> {
+public:
+  explicit SignalWatcher(std::shared_ptr<ServerState> state);
+  SignalWatcher(const SignalWatcher&) = delete;
+  SignalWatcher(SignalWatcher&&) = delete;
+  SignalWatcher& operator=(const SignalWatcher&) = delete;
+  SignalWatcher& operator=(SignalWatcher&&) = delete;
+  ~SignalWatcher() = default;
+
+protected:
+  phosg::PrefixedLogger log;
+  std::shared_ptr<ServerState> state;
+  std::unique_ptr<struct event, void (*)(struct event*)> sigusr1_event;
+  std::unique_ptr<struct event, void (*)(struct event*)> sigusr2_event;
+
+  static void dispatch_on_signal(evutil_socket_t, short, void* ctx);
+  void on_signal(int signum);
+};