#!/usr/bin/env python3 """Input relay for the Steam Frame: stable virtual devices, the 3D pointer, device rules. SteamVR opens /dev/input/event* only when it starts and never hotplugs, so a Bluetooth mouse that sleeps and reconnects (new event nodes) stops working until SteamVR restarts. This relay creates a virtual mouse and a virtual keyboard through /dev/uinput once, before SteamVR starts, and feeds them from the physical devices as they come and go. Every USB or Bluetooth mouse and keyboard is a candidate. A physical device is identified by its Bluetooth address (EVIOCGUNIQ) or USB bus:vendor:product:name, so all its event nodes share one role (the Swiftpoint Z3 has a mouse node and a keyboard node for its extra buttons). Roles, from ~/.config/frametop-input.json (written by the Frametop Input Settings app): pointer grabbed; drives the universal 3D mouse (default for devices with a mouse node) passthrough not grabbed, only observed, e.g. for the Meta dashboard shortcut (default for keyboards) ignore not grabbed, only observed for identification in the settings app Buttons and keys of pointer devices go through a per-device map to actions (left, right, middle, back, scroll_up, scroll_down, dashboard, recenter, pointer_toggle, sens_up, sens_down, layout_reset = put the desktop screens back in their saved layout, screens_toggle = hide or show the desktop screens, key = pass through as a key, none). Keys also go to ft-screens (@ft_screens, the Frametop desktop's compositor), which types them into the desktop screen that has focus (not while the SteamVR dashboard is open): from keyboards that aren't grabbed, and keys a pointer device passes through. Pointer mode (POINTER=1 in ~/.config/frametop.conf) sends pointer devices to the ft-pointer helper (pointer/helper), which drives the ft_pointer SteamVR driver. With POINTER=0, pointer devices go to the virtual mouse and keyboard instead. Control socket (abstract datagram @frametop_relay, JSON replies to the sender): devices list event nodes with id, name, kinds, role, grabbed watch stream input events from every candidate node (identification) reload re-read both config files, re-apply roles, tell the helper Runs on the Frame host as a user service (frametop-input-relay.service). The virtual devices are parked in systemd's file descriptor store, so a relay restart gets the same devices back and SteamVR never loses them. The service is Type=notify: READY=1 goes out only after the devices exist, so SteamVR (ordered after it) always finds them. Dependency-free: Python standard library plus the kernel's evdev and uinput interfaces. input-relay.py the service input-relay.py --no-grab never grab, for testing next to a running SteamVR """ import array import errno import fcntl import json import os import select import socket import struct import subprocess import sys import time # Linux input constants (include/uapi/linux/input-event-codes.h, input.h, uinput.h). EV_SYN, EV_KEY, EV_REL, EV_MSC = 0x00, 0x01, 0x02, 0x04 SYN_REPORT = 0 BTN_MISC, KEY_MAX = 0x100, 0x2FF KEY_A = 30 REL_X, REL_Y, REL_WHEEL, REL_MAX = 0x00, 0x01, 0x08, 0x0F BTN_LEFT, BTN_RIGHT, BTN_MIDDLE, BTN_SIDE, BTN_EXTRA = 0x110, 0x111, 0x112, 0x113, 0x114 KEY_LEFTMETA, KEY_RIGHTMETA = 125, 126 BUS_USB, BUS_BLUETOOTH, BUS_VIRTUAL = 0x03, 0x05, 0x06 # struct input_event on 64-bit: struct timeval (2 x long), u16 type, u16 code, s32 value. EVENT = struct.Struct("llHHi") def _ioc(direction, nr, size, kind): return (direction << 30) | (size << 16) | (ord(kind) << 8) | nr def _iow(kind, nr, size): return _ioc(1, nr, size, kind) def _ior(kind, nr, size): return _ioc(2, nr, size, kind) UI_DEV_CREATE = _ioc(0, 1, 0, "U") UI_DEV_DESTROY = _ioc(0, 2, 0, "U") UI_DEV_SETUP = _iow("U", 3, 92) # struct uinput_setup: input_id (4 x u16), name[80], u32 UI_SET_EVBIT = _iow("U", 100, 4) UI_SET_KEYBIT = _iow("U", 101, 4) UI_SET_RELBIT = _iow("U", 102, 4) EVIOCGRAB = _iow("E", 0x90, 4) EVIOCGID = _ior("E", 0x02, 8) EV_NAMES = {EV_KEY: "key", EV_REL: "rel"} def eviocgbit(ev, length): return _ior("E", 0x20 + ev, length) def eviocgname(length): return _ior("E", 0x06, length) def eviocguniq(length): return _ior("E", 0x08, length) VIRTUAL_PREFIX = "frametop virtual" RULES_PATH = os.path.expanduser("~/.config/frametop-input.json") ACTIONS = ("left", "right", "middle", "back", "scroll_up", "scroll_down", "dashboard", "recenter", "pointer_toggle", "sens_up", "sens_down", "layout_reset", "screens_toggle", "key", "none") SCREENS = "\0ft_screens" FT_LAYOUT = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "layout", "ft-layout") DEFAULT_BUTTONS = {BTN_LEFT: "left", BTN_RIGHT: "right", BTN_MIDDLE: "middle", BTN_SIDE: "back", BTN_EXTRA: "back"} def log(*args): print(*args, flush=True) def notify(state, fds=()): """sd_notify, with optional file descriptors for the fd store. No-op outside systemd.""" addr = os.environ.get("NOTIFY_SOCKET") if not addr: return if addr.startswith("@"): addr = "\0" + addr[1:] # socket.send_fds() ignores its address argument (Python 3.12), so use sendmsg. ancillary = [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))] if fds else [] try: with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as sock: sock.sendmsg([state.encode()], ancillary, 0, addr) except OSError as e: log(f"sd_notify failed ({state.splitlines()[0]}): {e}") def stored_fds(): """File descriptors handed back by systemd's fd store, by name.""" if os.environ.get("LISTEN_PID") != str(os.getpid()): return {} names = os.environ.get("LISTEN_FDNAMES", "").split(":") count = int(os.environ.get("LISTEN_FDS", "0")) return {names[i]: 3 + i for i in range(count) if i < len(names)} class Virtual: """One uinput device, reused from systemd's fd store when possible.""" def __init__(self, name, product, keys, rels, stored): self.dirty = False store_name = f"vdev{product}" if store_name in stored: self.fd = stored[store_name] os.set_blocking(self.fd, False) log(f"reusing {name} from the fd store") return self.fd = os.open("/dev/uinput", os.O_WRONLY | os.O_NONBLOCK) fcntl.ioctl(self.fd, UI_SET_EVBIT, EV_KEY) for code in keys: fcntl.ioctl(self.fd, UI_SET_KEYBIT, code) if rels: fcntl.ioctl(self.fd, UI_SET_EVBIT, EV_REL) for code in rels: fcntl.ioctl(self.fd, UI_SET_RELBIT, code) setup = struct.pack("HHHH80sI", BUS_VIRTUAL, 0x4D44, product, 1, name.encode(), 0) fcntl.ioctl(self.fd, UI_DEV_SETUP, setup) fcntl.ioctl(self.fd, UI_DEV_CREATE) notify(f"FDSTORE=1\nFDNAME={store_name}", [self.fd]) log(f"created {name}") def emit(self, etype, code, value): os.write(self.fd, EVENT.pack(0, 0, etype, code, value)) self.dirty = True def sync(self): if self.dirty: os.write(self.fd, EVENT.pack(0, 0, EV_SYN, SYN_REPORT, 0)) self.dirty = False def bits(fd, ev, count): buf = bytearray((count + 7) // 8) try: fcntl.ioctl(fd, eviocgbit(ev, len(buf)), buf) except OSError: return set() return {i for i in range(count) if buf[i // 8] >> (i % 8) & 1} def read_config(path=os.path.expanduser("~/.config/frametop.conf")): """KEY=VALUE lines, # comments allowed. Missing file means defaults.""" conf = {} try: with open(path) as f: for line in f: line = line.split("#", 1)[0].strip() if "=" in line: key, value = line.split("=", 1) conf[key.strip()] = value.strip() except OSError: pass return conf def read_rules(path=RULES_PATH): """{"devices": {id: {"role", "name"}}, "buttons": {id: {"": action}}}.""" try: with open(path) as f: rules = json.load(f) except (OSError, ValueError): rules = {} rules.setdefault("devices", {}) rules.setdefault("buttons", {}) return rules class Pointer: """Drives the ft_pointer SteamVR driver from a mouse (pointer mode). The virtual controller connects when the mouse is used (taking the right hand role and recentering on the gaze) and disconnects after `idle` seconds without mouse activity, so the real controllers get their role back: the last used device wins. """ DRIVER_BUTTONS = {"left": "trigger", "right": "b", "middle": "x", "back": "joystick"} SCROLL_PULSE = 0.08 # seconds of joystick deflection per wheel notch CLAIM_PULSE = 0.06 # seconds the claim button (switchlaserhand, no click) is held RESUME_PAUSE = 1.5 # mouse idle this long, then moving again, re-claims the laser WAKE_WINDOW = 1.0 # seconds in which WAKE_COUNTS of motion must add up def __init__(self, sensitivity, idle, wake_counts=40): self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) self.sensitivity = sensitivity # degrees per mouse count self.idle = idle self.active = False self.last_used = 0.0 self.dx = self.dy = 0 self.scroll_until = None self.claim_at = None # when to press the claim button self.claim_release = None self.system_at = None # dashboard toggle: when to press the virtual system button self.system_release = None # Waking (or re-claiming after a pause) needs deliberate movement, so sensor # jitter from a mouse lying on a desk can't steal the laser from a controller. self.wake_counts = wake_counts self.pending = 0 self.pending_since = 0.0 def send(self, command): try: self.sock.sendto(command.encode(), "\0ft_pointer_helper") except OSError: pass # helper not running (SteamVR not running) def wake(self, now): if not self.active: self.send("show") self.send("recenter") self.active = True self.claim_at = now + 0.3 # let SteamVR bind the freshly connected device first log("pointer on") elif now - self.last_used > self.RESUME_PAUSE and self.claim_at is None: self.claim_at = now # another device may have taken the laser meanwhile self.last_used = now def motion(self, code, value, now): dormant = not self.active or now - self.last_used > self.RESUME_PAUSE if dormant and code in (REL_X, REL_Y): if now - self.pending_since > self.WAKE_WINDOW: self.pending, self.pending_since = 0, now self.pending += abs(value) if self.pending < self.wake_counts: return # not yet deliberate movement self.pending = 0 self.wake(now) if code == REL_X: self.dx += value elif code == REL_Y: self.dy += value elif code == REL_WHEEL and value: self.send(f"scroll 0 {1 if value > 0 else -1}") self.scroll_until = now + self.SCROLL_PULSE def action(self, name, value, now): """A mapped button: value 1 press, 0 release, 2 autorepeat (ignored).""" if value == 2: return driver = self.DRIVER_BUTTONS.get(name) if driver: self.wake(now) self.flush() self.send(f"btn {driver} {value}") elif value != 1: return # the rest act on press elif name in ("scroll_up", "scroll_down"): self.wake(now) self.send(f"scroll 0 {1 if name == 'scroll_up' else -1}") self.scroll_until = now + self.SCROLL_PULSE elif name == "dashboard": self.dashboard(now) elif name == "recenter": self.wake(now) self.send("recenter") elif name == "pointer_toggle": if self.active: self.send("hide") self.active = False log("pointer off (toggle)") else: self.wake(now) elif name == "screens_toggle": try: self.sock.sendto(b"toggle", SCREENS) except OSError: pass # ft-screens not running elif name == "layout_reset": # Runs a few seconds and borrows the pointer; ft-layout refuses a second copy. subprocess.Popen([FT_LAYOUT, "apply"], stdin=subprocess.DEVNULL, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, start_new_session=True) log("layout reset") elif name in ("sens_up", "sens_down"): self.sensitivity *= 1.25 if name == "sens_up" else 0.8 log(f"sensitivity {self.sensitivity:.4f} deg/count") def flush(self): if self.dx or self.dy: # Mouse right turns the ray right (negative yaw); mouse down tilts it down. self.send(f"move {-self.dx * self.sensitivity:.4f} {-self.dy * self.sensitivity:.4f}") self.dx = self.dy = 0 def dashboard(self, now=None): """Toggle the SteamVR dashboard with the virtual controller's system button. SteamVR needs the button held for a frame or two (press and release in the same instant is ignored), and the virtual controller must be connected and bound, so wake it first when needed. """ now = time.monotonic() if now is None else now woke = not self.active self.wake(now) self.system_at = now + (0.4 if woke else 0.0) def tick(self, now): if self.system_at is not None and now >= self.system_at: self.send("btn system 1") self.system_at = None self.system_release = now + 0.12 elif self.system_release is not None and now >= self.system_release: self.send("btn system 0") self.system_release = None if self.claim_at is not None and now >= self.claim_at: self.send("btn a 1") self.claim_at = None self.claim_release = now + self.CLAIM_PULSE elif self.claim_release is not None and now >= self.claim_release: self.send("btn a 0") self.claim_release = None if self.scroll_until is not None and now >= self.scroll_until: self.send("scroll 0 0") self.scroll_until = None if self.active and now - self.last_used > self.idle: self.send("hide") self.active = False log("pointer off (idle)") def timeout(self): pending = (self.scroll_until, self.claim_at, self.claim_release, self.system_at, self.system_release) return 0.02 if any(t is not None for t in pending) else 0.5 class Node: """One input event node of a candidate device (mouse or keyboard, USB or Bluetooth).""" def __init__(self, path, fd, name, bus, vendor, product, uniq, is_mouse, is_keyboard): self.path, self.fd, self.name = path, fd, name self.bus, self.vendor, self.product, self.uniq = bus, vendor, product, uniq self.is_mouse, self.is_keyboard = is_mouse, is_keyboard # One physical device, whatever its node: Bluetooth address, else USB ids plus name. base = self.name.split(" Mouse")[0].split(" Keyboard")[0] self.id = uniq.lower() if uniq else f"usb:{vendor:04x}:{product:04x}:{base}" self.role = None self.grabbed = False self.held = set() # keys and buttons currently down, released if the device vanishes self.last_watch = 0.0 def describe(self): kinds = [k for k, on in (("mouse", self.is_mouse), ("keyboard", self.is_keyboard)) if on] return {"path": self.path, "name": self.name, "id": self.id, "uniq": self.uniq, "bus": {BUS_USB: "usb", BUS_BLUETOOTH: "bluetooth"}.get(self.bus, str(self.bus)), "kinds": kinds, "role": self.role, "grabbed": self.grabbed} def probe(path): """Open a node if it is a USB or Bluetooth mouse or keyboard, else return None.""" try: fd = os.open(path, os.O_RDONLY | os.O_NONBLOCK) except OSError: return None try: buf = bytearray(256) fcntl.ioctl(fd, eviocgname(len(buf)), buf) name = buf.split(b"\0", 1)[0].decode(errors="replace") ident = bytearray(8) fcntl.ioctl(fd, EVIOCGID, ident) bus, vendor, product, _ = struct.unpack("HHHH", ident) if name.startswith(VIRTUAL_PREFIX) or bus not in (BUS_USB, BUS_BLUETOOTH): raise ValueError uniq_buf = bytearray(64) try: fcntl.ioctl(fd, eviocguniq(len(uniq_buf)), uniq_buf) uniq = uniq_buf.split(b"\0", 1)[0].decode(errors="replace") except OSError: uniq = "" is_mouse = REL_X in bits(fd, EV_REL, REL_MAX + 1) is_keyboard = KEY_A in bits(fd, EV_KEY, KEY_MAX + 1) if not (is_mouse or is_keyboard): raise ValueError return Node(path, fd, name, bus, vendor, product, uniq, is_mouse, is_keyboard) except (OSError, ValueError): os.close(fd) return None def main(): can_grab = "--no-grab" not in sys.argv stored = stored_fds() mouse = Virtual(f"{VIRTUAL_PREFIX} mouse", 1, keys=range(BTN_MISC, 0x118), rels=range(REL_MAX + 1), stored=stored) keyboard = Virtual(f"{VIRTUAL_PREFIX} keyboard", 2, keys=range(1, BTN_MISC), rels=(), stored=stored) notify("READY=1") control = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) control.bind("\0frametop_relay") control.setblocking(False) watchers = {} # address -> watch end time state = {"pointer": None, "rules": {}} def load_config(): conf = read_config() state["rules"] = read_rules() if conf.get("POINTER", "0") == "1": p = state["pointer"] or Pointer(0.03, 30) p.sensitivity = float(conf.get("POINTER_SENSITIVITY", "0.03")) p.idle = float(conf.get("POINTER_IDLE", "30")) p.wake_counts = int(conf.get("POINTER_WAKE_COUNTS", "40")) state["pointer"] = p log(f"pointer mode: {p.sensitivity} deg/count, idle {p.idle} s, wake {p.wake_counts} counts") else: state["pointer"] = None log("pointer mode off: pointer devices feed the virtual mouse and keyboard") load_config() meta_down = False # Meta pressed with no other key yet: a tap toggles the dashboard screens_sock = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM | socket.SOCK_NONBLOCK) def to_screens(code, value): """A key for the desktop screens (ft-screens decides whether it types).""" if value in (0, 1) and code < BTN_MISC: try: screens_sock.sendto(f"key {code} {value}".encode(), SCREENS) except OSError: pass # ft-screens not running nodes = {} # fd -> Node seen = set() # paths already probed (rejected or open) next_scan = 0.0 def role_of(node): rule = state["rules"]["devices"].get(node.id, {}) if rule.get("role") in ("pointer", "passthrough", "ignore"): return rule["role"] has_mouse = any(n.is_mouse for n in nodes.values() if n.id == node.id) or node.is_mouse return "pointer" if has_mouse else "passthrough" def release_held(node): for code in node.held: (mouse if code >= BTN_MISC else keyboard).emit(EV_KEY, code, 0) node.held.clear() mouse.sync() keyboard.sync() def apply_roles(): for node in nodes.values(): role = role_of(node) want_grab = can_grab and role == "pointer" if want_grab != node.grabbed: try: fcntl.ioctl(node.fd, EVIOCGRAB, 1 if want_grab else 0) node.grabbed = want_grab except OSError as e: log(f"{'grab' if want_grab else 'ungrab'} failed for {node.name}: {e}") if not node.grabbed: release_held(node) if role != node.role: log(f"{node.name} ({node.path}, {node.id}): {role}{', grabbed' if node.grabbed else ''}") node.role = role def drop(node, reason): release_held(node) os.close(node.fd) del nodes[node.fd] seen.discard(node.path) log(f"released {node.name} ({node.path}): {reason}") def reply(addr, obj): try: control.sendto(json.dumps(obj).encode(), addr) except OSError: watchers.pop(addr, None) def handle_control(now): while True: try: data, addr = control.recvfrom(4096) except BlockingIOError: return if not addr: continue # unbound sender, nowhere to reply words = data.decode(errors="replace").split() cmd = words[0] if words else "" if cmd == "devices": reply(addr, {"t": "devices", "pointer_mode": state["pointer"] is not None, "actions": ACTIONS, "nodes": [n.describe() for n in nodes.values()]}) elif cmd == "watch": seconds = float(words[1]) if len(words) > 1 else 30 watchers[addr] = now + min(seconds, 600) reply(addr, {"t": "watching", "seconds": seconds}) elif cmd == "reload": load_config() apply_roles() if state["pointer"]: state["pointer"].send("reload") reply(addr, {"t": "reloaded"}) else: reply(addr, {"t": "error", "error": f"unknown command {cmd!r}"}) def broadcast(node, etype, code, value, now): if not watchers: return if etype == EV_REL and now - node.last_watch < 0.05: return # motion: enough for an activity light node.last_watch = now msg = {"t": "event", "id": node.id, "path": node.path, "name": node.name, "type": EV_NAMES.get(etype, str(etype)), "code": code, "value": value} for addr, until in list(watchers.items()): if now > until: del watchers[addr] else: reply(addr, msg) while True: now = time.monotonic() pointer = state["pointer"] if now >= next_scan: next_scan = now + 1.0 paths = {f"/dev/input/{n}" for n in os.listdir("/dev/input") if n.startswith("event")} seen &= paths | {n.path for n in nodes.values()} added = False for path in sorted(paths - seen): seen.add(path) node = probe(path) if node: nodes[node.fd] = node added = True if added: apply_roles() ready, _, _ = select.select(list(nodes) + [control], [], [], pointer.timeout() if pointer else 0.5) now = time.monotonic() if pointer: pointer.tick(now) for fd in ready: if fd is control: handle_control(now) continue node = nodes[fd] try: data = os.read(fd, EVENT.size * 64) except OSError as e: if e.errno == errno.EAGAIN: continue drop(node, os.strerror(e.errno)) continue if not data: drop(node, "closed") continue buttons = state["rules"]["buttons"].get(node.id, {}) for off in range(0, len(data) - EVENT.size + 1, EVENT.size): _, _, etype, code, value = EVENT.unpack_from(data, off) if etype in (EV_KEY, EV_REL): broadcast(node, etype, code, value, now) if node.role != "pointer": # Observed only. A Meta tap on any keyboard toggles the dashboard. if node.role == "passthrough" and etype == EV_KEY: to_screens(code, value) if pointer and node.role == "passthrough" and etype == EV_KEY: if code in (KEY_LEFTMETA, KEY_RIGHTMETA): if value == 1: meta_down = True elif value == 0 and meta_down: meta_down = False pointer.dashboard() elif value == 1: meta_down = False # Meta used as a modifier, not a tap continue if etype == EV_KEY: action = buttons.get(str(code), DEFAULT_BUTTONS.get(code, "key")) if pointer and action not in ("key", "none"): pointer.action(action, value, now) continue if action == "none": continue target = mouse if code >= BTN_MISC else keyboard target.emit(etype, code, value) to_screens(code, value) if value: node.held.add(code) else: node.held.discard(code) elif etype == EV_REL: if pointer: pointer.motion(code, value, now) else: mouse.emit(etype, code, value) elif etype == EV_SYN and code == SYN_REPORT: if pointer: pointer.flush() mouse.sync() keyboard.sync() if __name__ == "__main__": try: main() except KeyboardInterrupt: pass