Change from map to array

Signed-off-by: Sotiris Nanopoulos <sonanopo@microsoft.com>
envoyproxy · Dec 2, 2020 · c378f5f · c378f5f
1 parent 6cc663b
commit c378f5f
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Showing 5 changed files with 20 additions and 10 deletions.
diff --git a/include/envoy/common/platform.h b/include/envoy/common/platform.h
@@ -152,7 +152,8 @@ struct msghdr {
 #define HANDLE_ERROR_PERM ERROR_ACCESS_DENIED
 #define HANDLE_ERROR_INVALID ERROR_INVALID_HANDLE
 
-#define ENVOY_WIN32_SIGTERM 1
+#define ENVOY_WIN32_SIGNAL_COUNT 1
+#define ENVOY_WIN32_SIGTERM 0
 
 namespace Platform {
 constexpr absl::string_view null_device_path{"NUL"};

diff --git a/source/common/event/win32/signal_impl.cc b/source/common/event/win32/signal_impl.cc
@@ -9,11 +9,16 @@ namespace Event {
 
 SignalEventImpl::SignalEventImpl(DispatcherImpl& dispatcher, signal_t signal_num, SignalCb cb)
     : cb_(cb) {
-  auto handler_it = eventBridgeHandlersSingleton::get().find(signal_num);
-  if (handler_it != eventBridgeHandlersSingleton::get().end()) {
+
+  if (signal_num > eventBridgeHandlersSingleton::get().size()) {
+    ENVOY_BUG(false, "Attempting to create SignalEventImpl with a signal id that exceeds the "
+                     "number of supported signals.");
     return;
   }
 
+  if (eventBridgeHandlersSingleton::get()[signal_num]) {
+    return;
+  }
   os_fd_t socks[2];
   Api::SysCallIntResult result =
       Api::OsSysCallsSingleton::get().socketpair(AF_INET, SOCK_STREAM, IPPROTO_TCP, socks);
@@ -33,7 +38,7 @@ SignalEventImpl::SignalEventImpl(DispatcherImpl& dispatcher, signal_t signal_num
         cb_();
       },
       Event::FileTriggerType::Level, Event::FileReadyType::Read);
-  eventBridgeHandlersSingleton::get().insert({signal_num, write_handle});
+  eventBridgeHandlersSingleton::get()[signal_num] = write_handle;
 }
 
 } // namespace Event

diff --git a/source/common/event/win32/signal_impl.h b/source/common/event/win32/signal_impl.h
@@ -30,6 +30,6 @@ class SignalEventImpl : public SignalEvent {
 // Here we have a map from signal types to IoHandle. When we write to this handle we trigger an
 // event that notifies Envoy to act on the signal.
 using eventBridgeHandlersSingleton =
-    ThreadSafeSingleton<absl::flat_hash_map<signal_t, std::shared_ptr<Network::IoHandle>>>;
+    ThreadSafeSingleton<std::array<std::shared_ptr<Network::IoHandle>, ENVOY_WIN32_SIGNAL_COUNT>>;
 } // namespace Event
 } // namespace Envoy
diff --git a/source/exe/win32/platform_impl.cc b/source/exe/win32/platform_impl.cc
@@ -19,15 +19,19 @@ BOOL WINAPI CtrlHandler(DWORD fdwCtrlType) {
   }
   shutdown_pending = true;
 
-  auto eventBridgeHandlers = Event::eventBridgeHandlersSingleton::get();
-  auto handler_it = eventBridgeHandlers.find(ENVOY_WIN32_SIGTERM);
-  if (handler_it == eventBridgeHandlers.end() || !handler_it->second) {
+  auto handler = Event::eventBridgeHandlersSingleton::get()[ENVOY_WIN32_SIGTERM];
+  if (!handler) {
     return 0;
   }
+
+  // This code is executed as part of a thread running under a Windows
+  // context. For that reason we want to avoid allocating memory or
+  // taking locks. This is why we use dont want to just write to a socket
+  // to wake up the signal handler.
   Buffer::OwnedImpl buffer;
   constexpr absl::string_view data{"a"};
   buffer.add(data);
-  auto result = handler_it->second->write(buffer);
+  auto result = handler->write(buffer);
   RELEASE_ASSERT(result.rc_ == 1,
                  fmt::format("failed to write 1 byte: {}", result.err_->getErrorDetails()));
 

diff --git a/test/exe/win32_outofproc_main_test.cc b/test/exe/win32_outofproc_main_test.cc
@@ -64,7 +64,7 @@ INSTANTIATE_TEST_SUITE_P(IpVersions, MainCommonTest,
                          testing::ValuesIn(TestEnvironment::getIpVersionsForTest()),
                          TestUtility::ipTestParamsToString);
 
-TEST_P(MainCommonTest, Envoy1) {
+TEST_P(MainCommonTest, EnvoyHandlesCtrlBreakEvent) {
   createEnvoyProcess();
   ENVOY_LOG_MISC(warn, "Envoy process with pid {}", piProcInfo_.dwProcessId);
   Sleep(2 * 1000);