Add xdg-desktop-portal GlobalShortcuts backend for Wayland (Linux)

Implements a three-tier hotkey backend chain on Linux:
1. xdg-desktop-portal GlobalShortcuts — works on Hyprland, GNOME, and KDE
   without any privilege setup; requires one bind line in hyprland.conf for Hyprland
2. evdev — fallback for users in the input group or with systemd-logind seat ACLs
3. X11 XGrabKey — last resort for plain X11 sessions

Fixes double-fire on Hyprland by filtering signals by sig.Name to guard
against Deactivated events leaking through the Activated match rule.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-06-01 20:40:18 +03:00
parent 72f3ddde5f
commit fe74d20a3b
+178 -24
View File
@@ -12,12 +12,14 @@ import (
"strings"
"sync"
"syscall"
"time"
"unsafe"
dbus "github.com/godbus/dbus/v5"
"golang.design/x/hotkey"
)
// modMap is used by parseKeybind (shared with tests).
// modMap is used by parseKeybind (called from main.go and tests).
var modMap = map[string]hotkey.Modifier{
"ctrl": hotkey.ModCtrl,
"shift": hotkey.ModShift,
@@ -26,6 +28,152 @@ var modMap = map[string]hotkey.Modifier{
"super": hotkey.Mod4,
}
// ── Portal (xdg-desktop-portal GlobalShortcuts) ──────────────────────────────
// toPortalTrigger converts "ctrl+alt+m" → "<Control><Alt>m".
func toPortalTrigger(keybind string) string {
parts := strings.Split(strings.ToLower(strings.TrimSpace(keybind)), "+")
mods := map[string]string{
"ctrl": "<Control>", "shift": "<Shift>",
"alt": "<Alt>", "win": "<Super>", "super": "<Super>",
}
var sb strings.Builder
for _, p := range parts[:len(parts)-1] {
if m, ok := mods[strings.TrimSpace(p)]; ok {
sb.WriteString(m)
}
}
sb.WriteString(strings.TrimSpace(parts[len(parts)-1]))
return sb.String()
}
func startHotkeyPortal(keybind string) (<-chan struct{}, error) {
if os.Getenv("WAYLAND_DISPLAY") == "" {
return nil, fmt.Errorf("not a Wayland session")
}
conn, err := dbus.SessionBus()
if err != nil {
return nil, fmt.Errorf("D-Bus session bus: %w", err)
}
// ":1.123" → "1_123"
sender := strings.ReplaceAll(strings.TrimPrefix(conn.Names()[0], ":"), ".", "_")
portal := conn.Object("org.freedesktop.portal.Desktop", "/org/freedesktop/portal/desktop")
pid := os.Getpid()
awaitResponse := func(token string) (map[string]dbus.Variant, error) {
reqPath := dbus.ObjectPath(fmt.Sprintf(
"/org/freedesktop/portal/desktop/request/%s/%s", sender, token))
ch := make(chan *dbus.Signal, 8)
conn.Signal(ch)
defer conn.RemoveSignal(ch)
opts := []dbus.MatchOption{
dbus.WithMatchInterface("org.freedesktop.portal.Request"),
dbus.WithMatchMember("Response"),
dbus.WithMatchObjectPath(reqPath),
}
if err := conn.AddMatchSignal(opts...); err != nil {
return nil, err
}
defer conn.RemoveMatchSignal(opts...) //nolint:errcheck
for {
select {
case sig := <-ch:
if sig == nil || sig.Path != reqPath {
continue
}
if code, _ := sig.Body[0].(uint32); code != 0 {
return nil, fmt.Errorf("portal declined (code %d)", code)
}
if results, ok := sig.Body[1].(map[string]dbus.Variant); ok {
return results, nil
}
return map[string]dbus.Variant{}, nil
case <-time.After(30 * time.Second):
return nil, fmt.Errorf("portal response timed out")
}
}
}
// CreateSession
reqToken1 := fmt.Sprintf("dlm_r1_%d", pid)
sessToken := fmt.Sprintf("dlm_s_%d", pid)
if err := portal.Call("org.freedesktop.portal.GlobalShortcuts.CreateSession", 0,
map[string]dbus.Variant{
"handle_token": dbus.MakeVariant(reqToken1),
"session_handle_token": dbus.MakeVariant(sessToken),
}).Err; err != nil {
return nil, fmt.Errorf("GlobalShortcuts portal unavailable: %w", err)
}
if _, err := awaitResponse(reqToken1); err != nil {
return nil, fmt.Errorf("CreateSession: %w", err)
}
// xdg-desktop-portal-hyprland doesn't populate session_handle in the response
// (spec bug). The path is always predictable from sender + session token.
sessionHandle := dbus.ObjectPath(fmt.Sprintf(
"/org/freedesktop/portal/desktop/session/%s/%s", sender, sessToken))
// BindShortcuts — portal expects a(sa{sv}): array of (id, props) structs.
type shortcutEntry struct {
ID string
Props map[string]dbus.Variant
}
reqToken2 := fmt.Sprintf("dlm_r2_%d", pid)
shortcuts := []shortcutEntry{{
ID: "mute-toggle",
Props: map[string]dbus.Variant{
"description": dbus.MakeVariant("Toggle Discord Lobby Mute"),
"preferred_trigger": dbus.MakeVariant(toPortalTrigger(keybind)),
},
}}
if err := portal.Call("org.freedesktop.portal.GlobalShortcuts.BindShortcuts", 0,
sessionHandle, shortcuts, "", map[string]dbus.Variant{
"handle_token": dbus.MakeVariant(reqToken2),
}).Err; err != nil {
return nil, fmt.Errorf("BindShortcuts: %w", err)
}
if _, err := awaitResponse(reqToken2); err != nil {
return nil, fmt.Errorf("BindShortcuts: %w", err)
}
// Activated signals are emitted from /org/freedesktop/portal/desktop,
// not from the session handle path.
const portalDesktopPath = dbus.ObjectPath("/org/freedesktop/portal/desktop")
out := make(chan struct{}, 1)
sigCh := make(chan *dbus.Signal, 8)
conn.Signal(sigCh)
conn.AddMatchSignal( //nolint:errcheck
dbus.WithMatchInterface("org.freedesktop.portal.GlobalShortcuts"),
dbus.WithMatchMember("Activated"),
dbus.WithMatchObjectPath(portalDesktopPath),
)
go func() {
for sig := range sigCh {
if sig.Name != "org.freedesktop.portal.GlobalShortcuts.Activated" {
continue
}
if sig.Path != portalDesktopPath || len(sig.Body) < 2 {
continue
}
// Body: (o session_handle, s shortcut_id, t timestamp, a{sv} options)
if sh, _ := sig.Body[0].(dbus.ObjectPath); sh != sessionHandle {
continue
}
if id, _ := sig.Body[1].(string); id == "mute-toggle" {
select {
case out <- struct{}{}:
default:
}
}
}
}()
return out, nil
}
// ── evdev ─────────────────────────────────────────────────────────────────────
// evdev key codes from linux/input-event-codes.h
var evdevKeyMap = map[string]uint16{
"a": 30, "b": 48, "c": 46, "d": 32, "e": 18, "f": 33, "g": 34, "h": 35,
@@ -43,10 +191,10 @@ var evdevKeyMap = map[string]uint16{
// evdevModGroups maps each modifier to its [leftKey, rightKey] evdev codes.
var evdevModGroups = map[string][]uint16{
"ctrl": {29, 97}, // KEY_LEFTCTRL, KEY_RIGHTCTRL
"shift": {42, 54}, // KEY_LEFTSHIFT, KEY_RIGHTSHIFT
"alt": {56, 100}, // KEY_LEFTALT, KEY_RIGHTALT
"win": {125, 126}, // KEY_LEFTMETA, KEY_RIGHTMETA
"ctrl": {29, 97},
"shift": {42, 54},
"alt": {56, 100},
"win": {125, 126},
"super": {125, 126},
}
@@ -71,21 +219,17 @@ func parseEvdevKeybind(s string) (modGroups [][]uint16, mainKey uint16, err erro
return modGroups, k, nil
}
// eviocgbitKey is EVIOCGBIT(EV_KEY=1, 32) — returns a 256-bit mask of supported key codes.
// Computed as _IOC(_IOC_READ=2, 'E', 0x21, 32) on Linux x86-64.
// eviocgbitKey = EVIOCGBIT(EV_KEY=1, 32): 256-bit mask of supported key codes.
// _IOC(_IOC_READ=2, 'E', 0x21, 32) on Linux x86-64.
const eviocgbitKey = uintptr(0x80204521)
// hasKey reports whether the evdev device can produce the given key code.
func hasKey(f *os.File, code uint16) bool {
if code >= 256 {
return false
}
var bits [32]byte
_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, f.Fd(), eviocgbitKey, uintptr(unsafe.Pointer(&bits[0])))
if errno != 0 {
return false
}
return bits[code/8]&(1<<(code%8)) != 0
return errno == 0 && bits[code/8]&(1<<(code%8)) != 0
}
func comboActive(held map[uint16]bool, modGroups [][]uint16, mainKey uint16) bool {
@@ -107,14 +251,11 @@ func comboActive(held map[uint16]bool, modGroups [][]uint16, mainKey uint16) boo
return true
}
// startHotkeyEvdev registers the hotkey via raw evdev. Works on both X11 and Wayland.
// Requires the user to be in the 'input' group or have systemd-logind seat ACLs.
func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
modGroups, mainKey, err := parseEvdevKeybind(keybind)
if err != nil {
return nil, err
}
paths, _ := filepath.Glob("/dev/input/event*")
var devices []*os.File
for _, p := range paths {
@@ -122,7 +263,6 @@ func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
if err != nil {
continue
}
// Only keep devices that can actually produce the main key.
if hasKey(f, mainKey) {
devices = append(devices, f)
} else {
@@ -130,17 +270,15 @@ func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
}
}
if len(devices) == 0 {
return nil, fmt.Errorf("no accessible keyboard devices found in /dev/input add user to 'input' group")
return nil, fmt.Errorf("no accessible keyboard devices in /dev/input (add user to 'input' group)")
}
ch := make(chan struct{}, 1)
var mu sync.Mutex
held := make(map[uint16]bool)
for _, dev := range devices {
go func(f *os.File) {
defer f.Close()
// input_event on 64-bit Linux: 8+8 bytes timeval, 2 type, 2 code, 4 value = 24 bytes
// input_event on 64-bit Linux: 8+8 bytes timeval + 2+2+4 = 24 bytes
buf := make([]byte, 24)
for {
if _, err := io.ReadFull(f, buf); err != nil {
@@ -153,7 +291,7 @@ func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
value := int32(binary.LittleEndian.Uint32(buf[20:24]))
mu.Lock()
switch value {
case 1: // press
case 1:
held[code] = true
if comboActive(held, modGroups, mainKey) {
select {
@@ -161,7 +299,7 @@ func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
default:
}
}
case 0: // release
case 0:
delete(held, code)
}
mu.Unlock()
@@ -171,8 +309,23 @@ func startHotkeyEvdev(keybind string) (<-chan struct{}, error) {
return ch, nil
}
// startHotkey tries evdev first (Wayland + X11), falls back to X11 XGrabKey.
// ── startHotkey: portal → evdev → X11 ────────────────────────────────────────
func startHotkey(keybind string) (<-chan struct{}, error) {
// On Wayland, try xdg-desktop-portal GlobalShortcuts first.
// Works on GNOME, KDE, and Hyprland (via xdg-desktop-portal-hyprland)
// without any privilege setup.
if os.Getenv("WAYLAND_DISPLAY") != "" {
ch, err := startHotkeyPortal(keybind)
if err == nil {
log.Println("hotkey backend: xdg-desktop-portal")
return ch, nil
}
log.Printf("portal unavailable (%v), trying evdev", err)
}
// evdev: works on both X11 and Wayland if the user is in the 'input'
// group or systemd-logind grants seat ACLs (default on GNOME/KDE).
ch, err := startHotkeyEvdev(keybind)
if err == nil {
log.Println("hotkey backend: evdev")
@@ -180,13 +333,14 @@ func startHotkey(keybind string) (<-chan struct{}, error) {
}
log.Printf("evdev unavailable (%v), falling back to X11", err)
// X11 XGrabKey: works on plain X11 sessions.
mods, key, err2 := parseKeybind(keybind)
if err2 != nil {
return nil, err2
}
hk := hotkey.New(mods, key)
if err2 := hk.Register(); err2 != nil {
return nil, fmt.Errorf("X11 hotkey also failed (%v) — on Wayland add user to 'input' group", err2)
return nil, fmt.Errorf("all hotkey backends failed — on Wayland without xdg-desktop-portal support, add user to 'input' group: %v", err2)
}
log.Println("hotkey backend: X11")
out := make(chan struct{})