evdev: add evdev monitor for caps lock state

core/internal/mocks/evdev/mock_EvdevDevice.go

@@ -0,0 +1,295 @@
+// Code generated by mockery v2.53.5. DO NOT EDIT.
+
+package mocks_evdev
+
+import (
+	go_evdev "github.com/holoplot/go-evdev"
+	mock "github.com/stretchr/testify/mock"
+)
+
+// MockEvdevDevice is an autogenerated mock type for the EvdevDevice type
+type MockEvdevDevice struct {
+	mock.Mock
+}
+
+type MockEvdevDevice_Expecter struct {
+	mock *mock.Mock
+}
+
+func (_m *MockEvdevDevice) EXPECT() *MockEvdevDevice_Expecter {
+	return &MockEvdevDevice_Expecter{mock: &_m.Mock}
+}
+
+// Close provides a mock function with no fields
+func (_m *MockEvdevDevice) Close() error {
+	ret := _m.Called()
+
+	if len(ret) == 0 {
+		panic("no return value specified for Close")
+	}
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func() error); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
+// MockEvdevDevice_Close_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'Close'
+type MockEvdevDevice_Close_Call struct {
+	*mock.Call
+}
+
+// Close is a helper method to define mock.On call
+func (_e *MockEvdevDevice_Expecter) Close() *MockEvdevDevice_Close_Call {
+	return &MockEvdevDevice_Close_Call{Call: _e.mock.On("Close")}
+}
+
+func (_c *MockEvdevDevice_Close_Call) Run(run func()) *MockEvdevDevice_Close_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run()
+	})
+	return _c
+}
+
+func (_c *MockEvdevDevice_Close_Call) Return(_a0 error) *MockEvdevDevice_Close_Call {
+	_c.Call.Return(_a0)
+	return _c
+}
+
+func (_c *MockEvdevDevice_Close_Call) RunAndReturn(run func() error) *MockEvdevDevice_Close_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// Name provides a mock function with no fields
+func (_m *MockEvdevDevice) Name() (string, error) {
+	ret := _m.Called()
+
+	if len(ret) == 0 {
+		panic("no return value specified for Name")
+	}
+
+	var r0 string
+	var r1 error
+	if rf, ok := ret.Get(0).(func() (string, error)); ok {
+		return rf()
+	}
+	if rf, ok := ret.Get(0).(func() string); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(string)
+	}
+
+	if rf, ok := ret.Get(1).(func() error); ok {
+		r1 = rf()
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// MockEvdevDevice_Name_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'Name'
+type MockEvdevDevice_Name_Call struct {
+	*mock.Call
+}
+
+// Name is a helper method to define mock.On call
+func (_e *MockEvdevDevice_Expecter) Name() *MockEvdevDevice_Name_Call {
+	return &MockEvdevDevice_Name_Call{Call: _e.mock.On("Name")}
+}
+
+func (_c *MockEvdevDevice_Name_Call) Run(run func()) *MockEvdevDevice_Name_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run()
+	})
+	return _c
+}
+
+func (_c *MockEvdevDevice_Name_Call) Return(_a0 string, _a1 error) *MockEvdevDevice_Name_Call {
+	_c.Call.Return(_a0, _a1)
+	return _c
+}
+
+func (_c *MockEvdevDevice_Name_Call) RunAndReturn(run func() (string, error)) *MockEvdevDevice_Name_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// Path provides a mock function with no fields
+func (_m *MockEvdevDevice) Path() string {
+	ret := _m.Called()
+
+	if len(ret) == 0 {
+		panic("no return value specified for Path")
+	}
+
+	var r0 string
+	if rf, ok := ret.Get(0).(func() string); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(string)
+	}
+
+	return r0
+}
+
+// MockEvdevDevice_Path_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'Path'
+type MockEvdevDevice_Path_Call struct {
+	*mock.Call
+}
+
+// Path is a helper method to define mock.On call
+func (_e *MockEvdevDevice_Expecter) Path() *MockEvdevDevice_Path_Call {
+	return &MockEvdevDevice_Path_Call{Call: _e.mock.On("Path")}
+}
+
+func (_c *MockEvdevDevice_Path_Call) Run(run func()) *MockEvdevDevice_Path_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run()
+	})
+	return _c
+}
+
+func (_c *MockEvdevDevice_Path_Call) Return(_a0 string) *MockEvdevDevice_Path_Call {
+	_c.Call.Return(_a0)
+	return _c
+}
+
+func (_c *MockEvdevDevice_Path_Call) RunAndReturn(run func() string) *MockEvdevDevice_Path_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// ReadOne provides a mock function with no fields
+func (_m *MockEvdevDevice) ReadOne() (*go_evdev.InputEvent, error) {
+	ret := _m.Called()
+
+	if len(ret) == 0 {
+		panic("no return value specified for ReadOne")
+	}
+
+	var r0 *go_evdev.InputEvent
+	var r1 error
+	if rf, ok := ret.Get(0).(func() (*go_evdev.InputEvent, error)); ok {
+		return rf()
+	}
+	if rf, ok := ret.Get(0).(func() *go_evdev.InputEvent); ok {
+		r0 = rf()
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*go_evdev.InputEvent)
+		}
+	}
+
+	if rf, ok := ret.Get(1).(func() error); ok {
+		r1 = rf()
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// MockEvdevDevice_ReadOne_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'ReadOne'
+type MockEvdevDevice_ReadOne_Call struct {
+	*mock.Call
+}
+
+// ReadOne is a helper method to define mock.On call
+func (_e *MockEvdevDevice_Expecter) ReadOne() *MockEvdevDevice_ReadOne_Call {
+	return &MockEvdevDevice_ReadOne_Call{Call: _e.mock.On("ReadOne")}
+}
+
+func (_c *MockEvdevDevice_ReadOne_Call) Run(run func()) *MockEvdevDevice_ReadOne_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run()
+	})
+	return _c
+}
+
+func (_c *MockEvdevDevice_ReadOne_Call) Return(_a0 *go_evdev.InputEvent, _a1 error) *MockEvdevDevice_ReadOne_Call {
+	_c.Call.Return(_a0, _a1)
+	return _c
+}
+
+func (_c *MockEvdevDevice_ReadOne_Call) RunAndReturn(run func() (*go_evdev.InputEvent, error)) *MockEvdevDevice_ReadOne_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// State provides a mock function with given fields: t
+func (_m *MockEvdevDevice) State(t go_evdev.EvType) (go_evdev.StateMap, error) {
+	ret := _m.Called(t)
+
+	if len(ret) == 0 {
+		panic("no return value specified for State")
+	}
+
+	var r0 go_evdev.StateMap
+	var r1 error
+	if rf, ok := ret.Get(0).(func(go_evdev.EvType) (go_evdev.StateMap, error)); ok {
+		return rf(t)
+	}
+	if rf, ok := ret.Get(0).(func(go_evdev.EvType) go_evdev.StateMap); ok {
+		r0 = rf(t)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(go_evdev.StateMap)
+		}
+	}
+
+	if rf, ok := ret.Get(1).(func(go_evdev.EvType) error); ok {
+		r1 = rf(t)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// MockEvdevDevice_State_Call is a *mock.Call that shadows Run/Return methods with type explicit version for method 'State'
+type MockEvdevDevice_State_Call struct {
+	*mock.Call
+}
+
+// State is a helper method to define mock.On call
+//   - t go_evdev.EvType
+func (_e *MockEvdevDevice_Expecter) State(t interface{}) *MockEvdevDevice_State_Call {
+	return &MockEvdevDevice_State_Call{Call: _e.mock.On("State", t)}
+}
+
+func (_c *MockEvdevDevice_State_Call) Run(run func(t go_evdev.EvType)) *MockEvdevDevice_State_Call {
+	_c.Call.Run(func(args mock.Arguments) {
+		run(args[0].(go_evdev.EvType))
+	})
+	return _c
+}
+
+func (_c *MockEvdevDevice_State_Call) Return(_a0 go_evdev.StateMap, _a1 error) *MockEvdevDevice_State_Call {
+	_c.Call.Return(_a0, _a1)
+	return _c
+}
+
+func (_c *MockEvdevDevice_State_Call) RunAndReturn(run func(go_evdev.EvType) (go_evdev.StateMap, error)) *MockEvdevDevice_State_Call {
+	_c.Call.Return(run)
+	return _c
+}
+
+// NewMockEvdevDevice creates a new instance of MockEvdevDevice. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.
+// The first argument is typically a *testing.T value.
+func NewMockEvdevDevice(t interface {
+	mock.TestingT
+	Cleanup(func())
+}) *MockEvdevDevice {
+	mock := &MockEvdevDevice{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}

core/internal/server/evdev/handlers.go

@@ -0,0 +1,27 @@
+package evdev
+
+import (
+	"net"
+
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/models"
+)
+
+type Request struct {
+	ID     interface{}            `json:"id"`
+	Method string                 `json:"method"`
+	Params map[string]interface{} `json:"params"`
+}
+
+func HandleRequest(conn net.Conn, req Request, m *Manager) {
+	switch req.Method {
+	case "evdev.getState":
+		handleGetState(conn, req, m)
+	default:
+		models.RespondError(conn, req.ID.(int), "unknown method: "+req.Method)
+	}
+}
+
+func handleGetState(conn net.Conn, req Request, m *Manager) {
+	state := m.GetState()
+	models.Respond(conn, req.ID.(int), state)
+}

core/internal/server/evdev/handlers_test.go

@@ -0,0 +1,133 @@
+package evdev
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"net"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	mocks "github.com/AvengeMedia/DankMaterialShell/core/internal/mocks/evdev"
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/models"
+)
+
+type mockNetConn struct {
+	net.Conn
+	readBuf  *bytes.Buffer
+	writeBuf *bytes.Buffer
+	closed   bool
+}
+
+func newMockNetConn() *mockNetConn {
+	return &mockNetConn{
+		readBuf:  &bytes.Buffer{},
+		writeBuf: &bytes.Buffer{},
+	}
+}
+
+func (m *mockNetConn) Read(b []byte) (n int, err error) {
+	return m.readBuf.Read(b)
+}
+
+func (m *mockNetConn) Write(b []byte) (n int, err error) {
+	return m.writeBuf.Write(b)
+}
+
+func (m *mockNetConn) Close() error {
+	m.closed = true
+	return nil
+}
+
+func TestHandleRequest(t *testing.T) {
+	t.Run("getState request", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+		m := &Manager{
+			device:      mockDevice,
+			state:       State{Available: true, CapsLock: true},
+			subscribers: make(map[string]chan State),
+			closeChan:   make(chan struct{}),
+		}
+
+		conn := newMockNetConn()
+		req := Request{
+			ID:     123,
+			Method: "evdev.getState",
+			Params: map[string]interface{}{},
+		}
+
+		HandleRequest(conn, req, m)
+
+		var resp models.Response[State]
+		err := json.NewDecoder(conn.writeBuf).Decode(&resp)
+		require.NoError(t, err)
+
+		assert.Equal(t, 123, resp.ID)
+		assert.NotNil(t, resp.Result)
+		assert.True(t, resp.Result.Available)
+		assert.True(t, resp.Result.CapsLock)
+	})
+
+	t.Run("unknown method", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+		m := &Manager{
+			device:      mockDevice,
+			state:       State{Available: true, CapsLock: false},
+			subscribers: make(map[string]chan State),
+			closeChan:   make(chan struct{}),
+		}
+
+		conn := newMockNetConn()
+		req := Request{
+			ID:     456,
+			Method: "evdev.unknownMethod",
+			Params: map[string]interface{}{},
+		}
+
+		HandleRequest(conn, req, m)
+
+		var resp models.Response[any]
+		err := json.NewDecoder(conn.writeBuf).Decode(&resp)
+		require.NoError(t, err)
+
+		assert.Equal(t, 456, resp.ID)
+		assert.NotEmpty(t, resp.Error)
+		assert.Contains(t, resp.Error, "unknown method")
+	})
+}
+
+func TestHandleGetState(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	conn := newMockNetConn()
+	req := Request{
+		ID:     789,
+		Method: "evdev.getState",
+		Params: map[string]interface{}{},
+	}
+
+	handleGetState(conn, req, m)
+
+	var resp models.Response[State]
+	err := json.NewDecoder(conn.writeBuf).Decode(&resp)
+	require.NoError(t, err)
+
+	assert.Equal(t, 789, resp.ID)
+	assert.NotNil(t, resp.Result)
+	assert.True(t, resp.Result.Available)
+	assert.False(t, resp.Result.CapsLock)
+}

core/internal/server/evdev/manager.go

@@ -0,0 +1,256 @@
+package evdev
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/log"
+	evdev "github.com/holoplot/go-evdev"
+)
+
+const (
+	evKeyType      = 0x01
+	evLedType      = 0x11
+	keyCapslockKey = 58
+	ledCapslockKey = 1
+	keyStateOn     = 1
+)
+
+type EvdevDevice interface {
+	Name() (string, error)
+	Path() string
+	Close() error
+	ReadOne() (*evdev.InputEvent, error)
+	State(t evdev.EvType) (evdev.StateMap, error)
+}
+
+type Manager struct {
+	device      EvdevDevice
+	state       State
+	stateMutex  sync.RWMutex
+	subscribers map[string]chan State
+	subMutex    sync.RWMutex
+	closeChan   chan struct{}
+	closeOnce   sync.Once
+}
+
+func NewManager() (*Manager, error) {
+	device, err := findKeyboard()
+	if err != nil {
+		return nil, fmt.Errorf("failed to find keyboard: %w", err)
+	}
+
+	initialCapsLock := readInitialCapsLockState(device)
+
+	m := &Manager{
+		device:      device,
+		state:       State{Available: true, CapsLock: initialCapsLock},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	go m.monitorCapsLock()
+
+	return m, nil
+}
+
+func readInitialCapsLockState(device EvdevDevice) bool {
+	ledStates, err := device.State(evLedType)
+	if err != nil {
+		log.Debugf("Could not read LED state: %v", err)
+		return false
+	}
+
+	return ledStates[ledCapslockKey]
+}
+
+func findKeyboard() (EvdevDevice, error) {
+	pattern := "/dev/input/event*"
+	matches, err := filepath.Glob(pattern)
+	if err != nil {
+		return nil, fmt.Errorf("failed to glob input devices: %w", err)
+	}
+
+	if len(matches) == 0 {
+		return nil, fmt.Errorf("no input devices found")
+	}
+
+	for _, path := range matches {
+		device, err := evdev.Open(path)
+		if err != nil {
+			continue
+		}
+
+		if isKeyboard(device) {
+			deviceName, _ := device.Name()
+			log.Debugf("Found keyboard: %s at %s", deviceName, path)
+			return device, nil
+		}
+
+		device.Close()
+	}
+
+	return nil, fmt.Errorf("no keyboard device found")
+}
+
+func isKeyboard(device EvdevDevice) bool {
+	deviceName, err := device.Name()
+	if err != nil {
+		return false
+	}
+
+	name := strings.ToLower(deviceName)
+
+	switch {
+	case strings.Contains(name, "keyboard"):
+		return true
+	case strings.Contains(name, "kbd"):
+		return true
+	case strings.Contains(name, "input") && strings.Contains(name, "key"):
+		return true
+	default:
+		return false
+	}
+}
+
+func (m *Manager) monitorCapsLock() {
+	defer func() {
+		if r := recover(); r != nil {
+			log.Errorf("Panic in evdev monitor: %v", r)
+		}
+	}()
+
+	for {
+		select {
+		case <-m.closeChan:
+			return
+		default:
+		}
+
+		event, err := m.device.ReadOne()
+		if err != nil {
+			if !isClosedError(err) {
+				log.Warnf("Failed to read evdev event: %v", err)
+			}
+			time.Sleep(100 * time.Millisecond)
+			continue
+		}
+
+		if event == nil {
+			continue
+		}
+
+		if event.Type == evKeyType && event.Code == keyCapslockKey && event.Value == keyStateOn {
+			m.toggleCapsLock()
+		}
+	}
+}
+
+func isClosedError(err error) bool {
+	if err == nil {
+		return false
+	}
+
+	errStr := err.Error()
+	switch {
+	case strings.Contains(errStr, "closed"):
+		return true
+	case strings.Contains(errStr, "bad file descriptor"):
+		return true
+	default:
+		return false
+	}
+}
+
+func (m *Manager) toggleCapsLock() {
+	m.stateMutex.Lock()
+	m.state.CapsLock = !m.state.CapsLock
+	newState := m.state
+	m.stateMutex.Unlock()
+
+	log.Debugf("Caps lock toggled: %v", newState.CapsLock)
+	m.notifySubscribers(newState)
+}
+
+func (m *Manager) GetState() State {
+	m.stateMutex.RLock()
+	defer m.stateMutex.RUnlock()
+	return m.state
+}
+
+func (m *Manager) Subscribe(id string) chan State {
+	m.subMutex.Lock()
+	defer m.subMutex.Unlock()
+
+	ch := make(chan State, 16)
+	m.subscribers[id] = ch
+	return ch
+}
+
+func (m *Manager) Unsubscribe(id string) {
+	m.subMutex.Lock()
+	defer m.subMutex.Unlock()
+
+	if ch, ok := m.subscribers[id]; ok {
+		close(ch)
+		delete(m.subscribers, id)
+	}
+}
+
+func (m *Manager) notifySubscribers(state State) {
+	m.subMutex.RLock()
+	defer m.subMutex.RUnlock()
+
+	for _, ch := range m.subscribers {
+		select {
+		case ch <- state:
+		default:
+		}
+	}
+}
+
+func (m *Manager) Close() {
+	m.closeOnce.Do(func() {
+		close(m.closeChan)
+
+		if m.device != nil {
+			if err := m.device.Close(); err != nil && !isClosedError(err) {
+				log.Warnf("Error closing evdev device: %v", err)
+			}
+		}
+
+		m.subMutex.Lock()
+		for id, ch := range m.subscribers {
+			close(ch)
+			delete(m.subscribers, id)
+		}
+		m.subMutex.Unlock()
+	})
+}
+
+func InitializeManager() (*Manager, error) {
+	if os.Getuid() != 0 && !hasInputGroupAccess() {
+		return nil, fmt.Errorf("insufficient permissions to access input devices")
+	}
+
+	return NewManager()
+}
+
+func hasInputGroupAccess() bool {
+	pattern := "/dev/input/event*"
+	matches, err := filepath.Glob(pattern)
+	if err != nil || len(matches) == 0 {
+		return false
+	}
+
+	testFile, err := os.Open(matches[0])
+	if err != nil {
+		return false
+	}
+	testFile.Close()
+	return true
+}

core/internal/server/evdev/manager_test.go

@@ -0,0 +1,314 @@
+package evdev
+
+import (
+	"errors"
+	"testing"
+
+	evdev "github.com/holoplot/go-evdev"
+	"github.com/stretchr/testify/assert"
+
+	mocks "github.com/AvengeMedia/DankMaterialShell/core/internal/mocks/evdev"
+)
+
+func TestManager_Creation(t *testing.T) {
+	t.Run("manager created successfully with caps lock off", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+		m := &Manager{
+			device:      mockDevice,
+			state:       State{Available: true, CapsLock: false},
+			subscribers: make(map[string]chan State),
+			closeChan:   make(chan struct{}),
+		}
+
+		assert.NotNil(t, m)
+		assert.True(t, m.state.Available)
+		assert.False(t, m.state.CapsLock)
+	})
+
+	t.Run("manager created successfully with caps lock on", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+		m := &Manager{
+			device:      mockDevice,
+			state:       State{Available: true, CapsLock: true},
+			subscribers: make(map[string]chan State),
+			closeChan:   make(chan struct{}),
+		}
+
+		assert.NotNil(t, m)
+		assert.True(t, m.state.Available)
+		assert.True(t, m.state.CapsLock)
+	})
+}
+
+func TestManager_GetState(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	state := m.GetState()
+	assert.True(t, state.Available)
+	assert.False(t, state.CapsLock)
+}
+
+func TestManager_Subscribe(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	ch := m.Subscribe("test-client")
+	assert.NotNil(t, ch)
+	assert.Len(t, m.subscribers, 1)
+}
+
+func TestManager_Unsubscribe(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	ch := m.Subscribe("test-client")
+	assert.Len(t, m.subscribers, 1)
+
+	m.Unsubscribe("test-client")
+	assert.Len(t, m.subscribers, 0)
+
+	select {
+	case _, ok := <-ch:
+		assert.False(t, ok, "channel should be closed")
+	default:
+		t.Error("channel should be closed")
+	}
+}
+
+func TestManager_ToggleCapsLock(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	ch := m.Subscribe("test-client")
+
+	go func() {
+		m.toggleCapsLock()
+	}()
+
+	newState := <-ch
+	assert.True(t, newState.CapsLock)
+
+	go func() {
+		m.toggleCapsLock()
+	}()
+
+	newState = <-ch
+	assert.False(t, newState.CapsLock)
+}
+
+func TestManager_Close(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().Close().Return(nil).Once()
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	ch1 := m.Subscribe("client1")
+	ch2 := m.Subscribe("client2")
+
+	m.Close()
+
+	select {
+	case _, ok := <-ch1:
+		assert.False(t, ok, "channel 1 should be closed")
+	default:
+		t.Error("channel 1 should be closed")
+	}
+
+	select {
+	case _, ok := <-ch2:
+		assert.False(t, ok, "channel 2 should be closed")
+	default:
+		t.Error("channel 2 should be closed")
+	}
+
+	assert.Len(t, m.subscribers, 0)
+
+	m.Close()
+}
+
+func TestIsKeyboard(t *testing.T) {
+	tests := []struct {
+		name     string
+		devName  string
+		expected bool
+	}{
+		{"keyboard in name", "AT Translated Set 2 keyboard", true},
+		{"kbd in name", "USB kbd", true},
+		{"input and key", "input key device", true},
+		{"random device", "Mouse", false},
+		{"empty name", "", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			mockDevice := mocks.NewMockEvdevDevice(t)
+			mockDevice.EXPECT().Name().Return(tt.devName, nil).Once()
+
+			result := isKeyboard(mockDevice)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestIsKeyboard_ErrorHandling(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().Name().Return("", errors.New("device error")).Once()
+
+	result := isKeyboard(mockDevice)
+	assert.False(t, result)
+}
+
+func TestManager_MonitorCapsLock(t *testing.T) {
+	t.Run("caps lock key press toggles state", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+
+		capsLockEvent := &evdev.InputEvent{
+			Type:  evKeyType,
+			Code:  keyCapslockKey,
+			Value: keyStateOn,
+		}
+
+		mockDevice.EXPECT().ReadOne().Return(capsLockEvent, nil).Once()
+		mockDevice.EXPECT().ReadOne().Return(nil, errors.New("stop")).Maybe()
+		mockDevice.EXPECT().Close().Return(nil).Maybe()
+
+		m := &Manager{
+			device:      mockDevice,
+			state:       State{Available: true, CapsLock: false},
+			subscribers: make(map[string]chan State),
+			closeChan:   make(chan struct{}),
+		}
+
+		ch := m.Subscribe("test")
+
+		go m.monitorCapsLock()
+
+		state := <-ch
+		assert.True(t, state.CapsLock)
+
+		m.Close()
+	})
+}
+
+func TestIsClosedError(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      error
+		expected bool
+	}{
+		{"nil error", nil, false},
+		{"closed error", errors.New("device closed"), true},
+		{"bad file descriptor", errors.New("bad file descriptor"), true},
+		{"other error", errors.New("some other error"), false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := isClosedError(tt.err)
+			assert.Equal(t, tt.expected, result)
+		})
+	}
+}
+
+func TestNotifySubscribers(t *testing.T) {
+	mockDevice := mocks.NewMockEvdevDevice(t)
+	mockDevice.EXPECT().ReadOne().Return(nil, errors.New("test")).Maybe()
+	mockDevice.EXPECT().Close().Return(nil).Maybe()
+
+	m := &Manager{
+		device:      mockDevice,
+		state:       State{Available: true, CapsLock: false},
+		subscribers: make(map[string]chan State),
+		closeChan:   make(chan struct{}),
+	}
+
+	ch1 := m.Subscribe("client1")
+	ch2 := m.Subscribe("client2")
+
+	newState := State{Available: true, CapsLock: true}
+	go m.notifySubscribers(newState)
+
+	state1 := <-ch1
+	state2 := <-ch2
+
+	assert.Equal(t, newState, state1)
+	assert.Equal(t, newState, state2)
+
+	m.Close()
+}
+
+func TestReadInitialCapsLockState(t *testing.T) {
+	t.Run("caps lock is on", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		ledState := evdev.StateMap{
+			ledCapslockKey: true,
+		}
+		mockDevice.EXPECT().State(evdev.EvType(evLedType)).Return(ledState, nil).Once()
+
+		result := readInitialCapsLockState(mockDevice)
+		assert.True(t, result)
+	})
+
+	t.Run("caps lock is off", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		ledState := evdev.StateMap{
+			ledCapslockKey: false,
+		}
+		mockDevice.EXPECT().State(evdev.EvType(evLedType)).Return(ledState, nil).Once()
+
+		result := readInitialCapsLockState(mockDevice)
+		assert.False(t, result)
+	})
+
+	t.Run("error reading LED state", func(t *testing.T) {
+		mockDevice := mocks.NewMockEvdevDevice(t)
+		mockDevice.EXPECT().State(evdev.EvType(evLedType)).Return(nil, errors.New("read error")).Once()
+
+		result := readInitialCapsLockState(mockDevice)
+		assert.False(t, result)
+	})
+}
+
+func TestHasInputGroupAccess(t *testing.T) {
+	result := hasInputGroupAccess()
+	t.Logf("hasInputGroupAccess: %v", result)
+}

core/internal/server/evdev/models.go

@@ -0,0 +1,6 @@
+package evdev
+
+type State struct {
+	Available bool `json:"available"`
+	CapsLock  bool `json:"capsLock"`
+}

core/internal/server/router.go

@@ -9,6 +9,7 @@ import (
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/brightness"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/cups"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/dwl"
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/evdev"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/extworkspace"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/freedesktop"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/loginctl"
@@ -165,6 +166,20 @@ func RouteRequest(conn net.Conn, req models.Request) {
 		return
 	}
 
+	if strings.HasPrefix(req.Method, "evdev.") {
+		if evdevManager == nil {
+			models.RespondError(conn, req.ID, "evdev manager not initialized")
+			return
+		}
+		evdevReq := evdev.Request{
+			ID:     req.ID,
+			Method: req.Method,
+			Params: req.Params,
+		}
+		evdev.HandleRequest(conn, evdevReq, evdevManager)
+		return
+	}
+
 	switch req.Method {
 	case "ping":
 		models.Respond(conn, req.ID, "pong")

core/internal/server/server.go

@@ -18,6 +18,7 @@ import (
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/brightness"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/cups"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/dwl"
+	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/evdev"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/extworkspace"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/freedesktop"
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/loginctl"
@@ -28,7 +29,7 @@ import (
 	"github.com/AvengeMedia/DankMaterialShell/core/internal/server/wlroutput"
 )
 
-const APIVersion = 17
+const APIVersion = 18
 
 type Capabilities struct {
 	Capabilities []string `json:"capabilities"`
@@ -54,6 +55,7 @@ var dwlManager *dwl.Manager
 var extWorkspaceManager *extworkspace.Manager
 var brightnessManager *brightness.Manager
 var wlrOutputManager *wlroutput.Manager
+var evdevManager *evdev.Manager
 var wlContext *wlcontext.SharedContext
 
 var capabilitySubscribers = make(map[string]chan ServerInfo)
@@ -292,6 +294,19 @@ func InitializeWlrOutputManager() error {
 	return nil
 }
 
+func InitializeEvdevManager() error {
+	manager, err := evdev.InitializeManager()
+	if err != nil {
+		log.Warnf("Failed to initialize evdev manager: %v", err)
+		return err
+	}
+
+	evdevManager = manager
+
+	log.Info("Evdev manager initialized")
+	return nil
+}
+
 func handleConnection(conn net.Conn) {
 	defer conn.Close()
 
@@ -358,6 +373,10 @@ func getCapabilities() Capabilities {
 		caps = append(caps, "wlroutput")
 	}
 
+	if evdevManager != nil {
+		caps = append(caps, "evdev")
+	}
+
 	return Capabilities{Capabilities: caps}
 }
 
@@ -404,6 +423,10 @@ func getServerInfo() ServerInfo {
 		caps = append(caps, "wlroutput")
 	}
 
+	if evdevManager != nil {
+		caps = append(caps, "evdev")
+	}
+
 	return ServerInfo{
 		APIVersion:   APIVersion,
 		Capabilities: caps,
@@ -918,6 +941,38 @@ func handleSubscribe(conn net.Conn, req models.Request) {
 		}()
 	}
 
+	if shouldSubscribe("evdev") && evdevManager != nil {
+		wg.Add(1)
+		evdevChan := evdevManager.Subscribe(clientID + "-evdev")
+		go func() {
+			defer wg.Done()
+			defer evdevManager.Unsubscribe(clientID + "-evdev")
+
+			initialState := evdevManager.GetState()
+			select {
+			case eventChan <- ServiceEvent{Service: "evdev", Data: initialState}:
+			case <-stopChan:
+				return
+			}
+
+			for {
+				select {
+				case state, ok := <-evdevChan:
+					if !ok {
+						return
+					}
+					select {
+					case eventChan <- ServiceEvent{Service: "evdev", Data: state}:
+					case <-stopChan:
+						return
+					}
+				case <-stopChan:
+					return
+				}
+			}
+		}()
+	}
+
 	go func() {
 		wg.Wait()
 		close(eventChan)
@@ -974,6 +1029,9 @@ func cleanupManagers() {
 	if wlrOutputManager != nil {
 		wlrOutputManager.Close()
 	}
+	if evdevManager != nil {
+		evdevManager.Close()
+	}
 	if wlContext != nil {
 		wlContext.Close()
 	}
@@ -1122,6 +1180,9 @@ func Start(printDocs bool) error {
 		log.Info("     - transform    : Transform value (optional)")
 		log.Info("     - scale        : Scale value (optional)")
 		log.Info("     - adaptiveSync : Adaptive sync state (optional)")
+		log.Info("Evdev:")
+		log.Info(" evdev.getState                        - Get current evdev state (caps lock)")
+		log.Info(" evdev.subscribe                       - Subscribe to evdev state changes (streaming)")
 		log.Info("")
 	}
 	log.Info("Initializing managers...")
@@ -1194,10 +1255,8 @@ func Start(printDocs bool) error {
 	fatalErrChan := make(chan error, 1)
 	if wlrOutputManager != nil {
 		go func() {
-			select {
-			case err := <-wlrOutputManager.FatalError():
-				fatalErrChan <- fmt.Errorf("WlrOutput fatal error: %w", err)
-			}
+			err := <-wlrOutputManager.FatalError()
+			fatalErrChan <- fmt.Errorf("WlrOutput fatal error: %w", err)
 		}()
 	}
 
@@ -1209,6 +1268,14 @@ func Start(printDocs bool) error {
 		}
 	}()
 
+	go func() {
+		if err := InitializeEvdevManager(); err != nil {
+			log.Debugf("Evdev manager unavailable: %v", err)
+		} else {
+			notifyCapabilityChange()
+		}
+	}()
+
 	if wlContext != nil {
 		wlContext.Start()
 		log.Info("Wayland event dispatcher started")