Merge pull request #183 from aragon999/fix/keypress-systemd-issue

Register keys for keypress only when needed.

TODO: Apply this for axes too?

src/logid/InputDevice.cpp

@@ -43,10 +43,19 @@ InputDevice::InputDevice(const char* name)
     device = libevdev_new();
     libevdev_set_name(device, name);
 
-    ///TODO: Is it really a good idea to enable all events?
     libevdev_enable_event_type(device, EV_KEY);
-    for(unsigned int i = 0; i < KEY_CNT; i++)
-        libevdev_enable_event_code(device, EV_KEY, i, nullptr);
+    for (unsigned int i = 0; i < KEY_CNT; i++) {
+        // Enable some keys which a normal keyboard should have
+        // by default, i.e. a-z, modifier keys and so on, see:
+        // /usr/include/linux/input-event-codes.h
+        if (i < 128) {
+            registered_keys[i] = true;
+            libevdev_enable_event_code(device, EV_KEY, i, nullptr);
+        } else {
+            registered_keys[i] = false;
+        }
+    }
+
     libevdev_enable_event_type(device, EV_REL);
     for(unsigned int i = 0; i < REL_CNT; i++)
         libevdev_enable_event_code(device, EV_REL, i, nullptr);
@@ -54,8 +63,10 @@ InputDevice::InputDevice(const char* name)
     int err = libevdev_uinput_create_from_device(device,
             LIBEVDEV_UINPUT_OPEN_MANAGED, &ui_device);
 
-    if(err != 0)
+    if(err != 0) {
+        libevdev_free(device);
         throw std::system_error(-err, std::generic_category());
+    }
 }
 
 InputDevice::~InputDevice()
@@ -64,6 +75,28 @@ InputDevice::~InputDevice()
     libevdev_free(device);
 }
 
+void InputDevice::registerKey(uint code)
+{
+    if (registered_keys[code]) {
+        return;
+    }
+
+    libevdev_uinput_destroy(ui_device);
+
+    libevdev_enable_event_code(device, EV_KEY, code, nullptr);
+    int err = libevdev_uinput_create_from_device(device,
+            LIBEVDEV_UINPUT_OPEN_MANAGED, &ui_device);
+
+    if(err != 0) {
+        libevdev_free(device);
+        device = nullptr;
+        ui_device = nullptr;
+        throw std::system_error(-err, std::generic_category());
+    }
+
+    registered_keys[code] = true;
+}
+
 void InputDevice::moveAxis(uint axis, int movement)
 {
     _sendEvent(EV_REL, axis, movement);
@@ -119,4 +152,4 @@ void InputDevice::_sendEvent(uint type, uint code, int value)
 {
     libevdev_uinput_write_event(ui_device, type, code, value);
     libevdev_uinput_write_event(ui_device, EV_SYN, SYN_REPORT, 0);
-}
+}

src/logid/InputDevice.h

@@ -20,6 +20,7 @@
 #define LOGID_INPUTDEVICE_H
 
 #include <memory>
+#include <string>
 
 extern "C"
 {
@@ -43,6 +44,7 @@ namespace logid
         explicit InputDevice(const char *name);
         ~InputDevice();
 
+        void registerKey(uint code);
         void moveAxis(uint axis, int movement);
         void pressKey(uint code);
         void releaseKey(uint code);
@@ -56,6 +58,7 @@ namespace logid
 
         static uint _toEventCode(uint type, const std::string& name);
 
+        bool registered_keys[KEY_CNT];
         libevdev* device;
         libevdev_uinput* ui_device{};
     };
@@ -63,4 +66,4 @@ namespace logid
     extern std::unique_ptr<InputDevice> virtual_input;
 }
 
-#endif //LOGID_INPUTDEVICE_H
+#endif //LOGID_INPUTDEVICE_H

src/logid/actions/KeypressAction.cpp

@@ -64,9 +64,11 @@ KeypressAction::Config::Config(Device* device, libconfig::Setting& config) :
                 auto& key = keys[i];
                 if(key.isNumber()) {
                     _keys.push_back(key);
+                    virtual_input->registerKey(key);
                 } else if(key.getType() == libconfig::Setting::TypeString) {
                     try {
                         _keys.push_back(virtual_input->toKeyCode(key));
+                        virtual_input->registerKey(virtual_input->toKeyCode(key));
                     } catch(InputDevice::InvalidEventCode& e) {
                         logPrintf(WARN, "Line %d: Invalid keycode %s, skipping."
                             , key.getSourceLine(), key.c_str());