Capture windows shutdown signal.

Author: evoskuil

Makefile.am

@@ -96,6 +96,7 @@ console_bs_SOURCES = \
     console/executor_store.cpp \
     console/executor_test_reader.cpp \
     console/executor_test_writer.cpp \
+    console/executor_windows.cpp \
     console/localize.hpp \
     console/main.cpp \
     console/stack_trace.cpp \

builds/cmake/CMakeLists.txt

@@ -334,6 +334,7 @@ if (with-console)
         "../../console/executor_store.cpp"
         "../../console/executor_test_reader.cpp"
         "../../console/executor_test_writer.cpp"
+        "../../console/executor_windows.cpp"
         "../../console/libbitcoin.ico"
         "../../console/localize.hpp"
         "../../console/main.cpp"

builds/msvc/vs2022/bs/bs.vcxproj

@@ -139,6 +139,7 @@
     <ClCompile Include="..\..\..\..\console\executor_store.cpp" />
     <ClCompile Include="..\..\..\..\console\executor_test_reader.cpp" />
     <ClCompile Include="..\..\..\..\console\executor_test_writer.cpp" />
+    <ClCompile Include="..\..\..\..\console\executor_windows.cpp" />
     <ClCompile Include="..\..\..\..\console\main.cpp" />
     <ClCompile Include="..\..\..\..\console\stack_trace.cpp" />
   </ItemGroup>

builds/msvc/vs2022/bs/bs.vcxproj.filters

@@ -81,6 +81,9 @@
     <ClCompile Include="..\..\..\..\console\executor_test_writer.cpp">
       <Filter>src</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\..\console\executor_windows.cpp">
+      <Filter>src</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\..\console\main.cpp">
       <Filter>src</Filter>
     </ClCompile>
@@ -116,4 +119,4 @@
       <Filter>resource</Filter>
     </ResourceCompile>
   </ItemGroup>
-</Project>
+</Project>

console/executor.cpp

@@ -31,9 +31,11 @@ namespace server {
 using boost::format;
 using namespace std::placeholders;
 
-std::atomic_bool executor::cancel_{};
+// static initializers.
 std::thread executor::stop_poller_{};
 std::promise<bool> executor::stopping_{};
+std::atomic<bool> executor::initialized_{};
+std::atomic<int> executor::signal_{ unsignalled };
 
 executor::executor(parser& metadata, std::istream& input, std::ostream& output,
     std::ostream&)
@@ -56,45 +58,35 @@ executor::executor(parser& metadata, std::istream& input, std::ostream& output,
         metadata.configured.log.verbose
     }
 {
-    initialize_stop();
-}
+    BC_ASSERT(!initialized_);
+    initialized_ = true;
 
-// Stop signal.
-// ----------------------------------------------------------------------------
+    initialize_stop();
 
 #if defined(HAVE_MSC)
-BOOL WINAPI executor::win32_handler(DWORD signal)
+    create_hidden_window();
+#endif
+}
+
+executor::~executor()
 {
-    ////if (auto* log = fopen("shutdown.log", "a"))
-    ////{
-    ////    fprintf(log, "Signal %lu at %llu\n", signal, GetTickCount64());
-    ////    fflush(log);
-    ////    fclose(log);
-    ////}
+    initialized_ = false;
 
-    switch (signal)
-    {
-        case CTRL_C_EVENT:
-        case CTRL_BREAK_EVENT:
-        case CTRL_CLOSE_EVENT:
-        case CTRL_LOGOFF_EVENT:
-        case CTRL_SHUTDOWN_EVENT:
-            executor::handle_stop({});
-            return TRUE;
-        default:
-            return FALSE;
-    }
-}
+#if defined(HAVE_MSC)
+    destroy_hidden_window();
 #endif
+}
+
+// Stop signal.
+// ----------------------------------------------------------------------------
+// static
 
-// Call only once.
 void executor::initialize_stop()
 {
     poll_for_stopping();
 
 #if defined(HAVE_MSC)
-    // TODO: use RegisterServiceCtrlHandlerEx for service registration.
-    ::SetConsoleCtrlHandler(&executor::win32_handler, TRUE);
+    ::SetConsoleCtrlHandler(&executor::control_handler, TRUE);
 #else
     // Restart interrupted system calls.
     struct sigaction action
@@ -123,34 +115,72 @@ void executor::initialize_stop()
 #endif
 }
 
+// Handle the stop signal and invoke stop method (requries signal safe code).
+void executor::handle_stop(int signal)
+{
+    stop(signal);
+}
+
+// Manage race between console stop and server stop.
+void executor::stop(int signal)
+{
+    ////if (auto* log = fopen("shutdown.log", "a"))
+    ////{
+    ////    fprintf(log, "stop %lu at %llu\n", signal, GetTickCount64());
+    ////    fflush(log);
+    ////    fclose(log);
+    ////}
+
+    // Implementation is limited to signal safe code.
+    static_assert(std::atomic<int>::is_always_lock_free);
+
+    // Capture first handled signal value.
+    auto unset = unsignalled;
+    signal_.compare_exchange_strong(unset, signal, std::memory_order_acq_rel);
+}
+
+// Any thread can monitor this for stopping.
+bool executor::canceled()
+{
+    return signal_.load(std::memory_order_acquire) != unsignalled;
+}
+
+// Spinning must be used in signal handler, cannot wait on a promise.
 void executor::poll_for_stopping()
 {
+    using namespace std::this_thread;
+
     stop_poller_ = std::thread([]()
     {
-        while (!cancel_.load(std::memory_order_acquire))
-            std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        while (!canceled())
+            sleep_for(std::chrono::milliseconds(10));
 
         stopping_.set_value(true);
     });
 }
 
+// Blocks until stopping is signalled by poller.
 void executor::wait_for_stopping()
 {
     stopping_.get_future().wait();
     if (stop_poller_.joinable())
         stop_poller_.join();
 }
 
-// Implementation is limited to signal safe code.
-void executor::handle_stop(int)
+// Suspend verbose logging and log the stop signal.
+void executor::log_stopping()
 {
-    stop();
-}
+    const auto signal = signal_.load();
+    if (signal == signal_none)
+        return;
 
-// Manage the race between console stop and server stop.
-void executor::stop()
-{
-    cancel_.store(true, std::memory_order_release);
+    // A high level of consolve logging can obscure and delay stop.
+    toggle_.at(network::levels::protocol) = false;
+    toggle_.at(network::levels::verbose) = false;
+    toggle_.at(network::levels::proxy) = false;
+
+    logger(format(BS_NODE_INTERRUPTED) % signal);
+    logger(BS_NETWORK_STOPPING);
 }
 
 // Event handlers.

console/executor.hpp

@@ -28,12 +28,10 @@
 #include <bitcoin/server.hpp>
 #include <boost/format.hpp>
 
-// This class is just an ad-hoc user interface wrapper on the node.
-// It will be factored and cleaned up for final release.
-
 namespace libbitcoin {
 namespace server {
 
+// This class is just an ad-hoc user interface wrapper on the node.
 class executor
 {
 public:
@@ -43,21 +41,38 @@ class executor
     executor(parser& metadata, std::istream&, std::ostream& output,
         std::ostream& error);
 
+    // Clean up.
+    ~executor();
+
     // Called from main.
     bool dispatch();
 
 private:
+    static constexpr int unsignalled{ -1 };
+    static constexpr int signal_none{ -2 };
+
     // Executor (static).
     static void initialize_stop();
     static void poll_for_stopping();
     static void wait_for_stopping();
     static void handle_stop(int code);
-    static void stop();
+    static void stop(int signal=signal_none);
+    static bool canceled();
+
 #if defined(HAVE_MSC)
-    static BOOL WINAPI win32_handler(DWORD signal);
+    static BOOL WINAPI control_handler(DWORD signal);
+    static LRESULT CALLBACK window_proc(HWND handle, UINT message,
+        WPARAM wparam, LPARAM lparam);
+
+    void create_hidden_window();
+    void destroy_hidden_window();
+
+    HWND window_{};
+    std::thread thread_{};
 #endif
 
     // Executor.
+    void log_stopping();
     void handle_started(const system::code& ec);
     void handle_subscribed(const system::code& ec, size_t key);
     void handle_running(const system::code& ec);
@@ -155,8 +170,9 @@ class executor
     static const std::unordered_map<uint8_t, std::string> fired_;
 
     // Shutdown.
-    static std::atomic_bool cancel_;
     static std::thread stop_poller_;
+    static std::atomic<int> signal_;
+    static std::atomic<bool> initialized_;
     static std::promise<bool> stopping_;
     std::promise<bool> log_suspended_{};
 

console/executor_runner.cpp

@@ -36,7 +36,7 @@ void executor::stopper(const std::string& message)
     capture_.stop();
 
     // Stop log, causing final message to be buffered by handler.
-    log_.stop(message, network::levels::application);
+    log_.stop(message,levels::application);
 
     // Suspend process termination until final message is buffered.
     log_suspended_.get_future().wait();
@@ -46,7 +46,7 @@ void executor::subscribe_connect()
 {
     node_->subscribe_connect
     (
-        [&](const code&, const network::channel::ptr&)
+        [&](const code&, const channel::ptr&)
         {
             log_.write(levels::verbose) <<
                 "{in:" << node_->inbound_channel_count() << "}"
@@ -162,13 +162,12 @@ bool executor::do_run()
     logger(BS_NETWORK_STARTING);
     node_->start(std::bind(&executor::handle_started, this, _1));
 
-    // Wait on signal to stop node (<ctrl-c>).
+    // Wait on signal to stop node (<ctrl-c>, etc).
     wait_for_stopping();
-    toggle_.at(levels::protocol) = false;
-    logger(BS_NETWORK_STOPPING);
 
     // Stop network (if not already stopped by self).
     // Blocks on join of server/node/network threadpool.
+    log_stopping();
     node_->close();
 
     // Sizes and records change, buckets don't.