domizianie

.config/sway/bin/assign-cgroups.py

@@ -0,0 +1,269 @@
+#!/usr/bin/python3
+"""
+Automatically assign a dedicated systemd scope to the GUI applications
+launched in the same cgroup as the compositor. This could be helpful for
+implementing cgroup-based resource management and would be necessary when
+`systemd-oomd` is in use.
+
+Limitations: The script is using i3ipc window:new event to detect application
+launches and would fail to detect background apps or special surfaces.
+Therefore it's recommended to supplement the script with use of systemd user
+services for such background apps.
+
+Dependencies: dbus-next, i3ipc, psutil, tenacity, python-xlib
+"""
+import argparse
+import asyncio
+import logging
+import socket
+import struct
+from typing import Optional
+
+from dbus_next import Variant
+from dbus_next.aio import MessageBus
+from dbus_next.errors import DBusError
+from i3ipc import Event
+from i3ipc.aio import Con, Connection
+from psutil import Process
+from tenacity import retry, retry_if_exception_type, stop_after_attempt
+from Xlib import X
+from Xlib.display import Display
+
+try:
+    # requires python-xlib >= 0.30
+    from Xlib.ext import res as XRes
+except ImportError:
+    XRes = None
+
+
+LOG = logging.getLogger("assign-cgroups")
+SD_BUS_NAME = "org.freedesktop.systemd1"
+SD_OBJECT_PATH = "/org/freedesktop/systemd1"
+SD_SLICE_FORMAT = "app-{app_id}.slice"
+SD_UNIT_FORMAT = "app-{app_id}-{unique}.scope"
+# Ids of known launcher applications that are not special surfaces. When the app is
+# started using one of those, it should be moved to a new cgroup.
+# Launcher should only be listed here if it creates cgroup of its own.
+LAUNCHER_APPS = ["nwggrid"]
+
+
+def get_cgroup(pid: int) -> Optional[str]:
+    """
+    Get cgroup identifier for the process specified by pid.
+    Assumes cgroups v2 unified hierarchy.
+    """
+    try:
+        with open(f"/proc/{pid}/cgroup", "r") as file:
+            cgroup = file.read()
+        return cgroup.strip().split(":")[-1]
+    except OSError:
+        LOG.exception("Error geting cgroup info")
+    return None
+
+
+def get_pid_by_socket(sockpath: str) -> int:
+    """
+    getsockopt (..., SO_PEERCRED, ...) returns the following structure
+    struct ucred
+    {
+      pid_t pid; /* s32: PID of sending process.  */
+      uid_t uid; /* u32: UID of sending process.  */
+      gid_t gid; /* u32: GID of sending process.  */
+    };
+    See also: socket(7), unix(7)
+    """
+    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
+        sock.connect(sockpath)
+        ucred = sock.getsockopt(
+            socket.SOL_SOCKET, socket.SO_PEERCRED, struct.calcsize("iII")
+        )
+    pid, _, _ = struct.unpack("iII", ucred)
+    return pid
+
+
+def escape_app_id(app_id: str) -> str:
+    """Escape app_id for systemd APIs"""
+    return app_id.replace("-", "\\x2d")
+
+
+class XlibHelper:
+    """Utility class for some X11-specific logic"""
+
+    def __init__(self):
+        self.display = Display()
+        self.use_xres = self._try_init_xres()
+
+    def _try_init_xres(self) -> bool:
+        if XRes is None or self.display.query_extension(XRes.extname) is None:
+            LOG.warning(
+                "X-Resource extension is not supported. "
+                "Process identification for X11 applications will be less reliable."
+            )
+            return False
+        ver = self.display.res_query_version()
+        LOG.info(
+            "X-Resource version %d.%d",
+            ver.server_major,
+            ver.server_minor,
+        )
+        return (ver.server_major, ver.server_minor) >= (1, 2)
+
+    def get_net_wm_pid(self, wid: int) -> int:
+        """Get PID from _NET_WM_PID property of X11 window"""
+        window = self.display.create_resource_object("window", wid)
+        net_wm_pid = self.display.get_atom("_NET_WM_PID")
+        pid = window.get_full_property(net_wm_pid, X.AnyPropertyType)
+
+        if pid is None:
+            raise Exception("Failed to get PID from _NET_WM_PID")
+        return int(pid.value.tolist()[0])
+
+    def get_xres_client_id(self, wid: int) -> int:
+        """Get PID from X server via X-Resource extension"""
+        res = self.display.res_query_client_ids(
+            [{"client": wid, "mask": XRes.LocalClientPIDMask}]
+        )
+        for cid in res.ids:
+            if cid.spec.client > 0 and cid.spec.mask == XRes.LocalClientPIDMask:
+                for value in cid.value:
+                    return value
+        raise Exception("Failed to get PID via X-Resource extension")
+
+    def get_window_pid(self, wid: int) -> Optional[int]:
+        """Get PID of X11 window"""
+        if self.use_xres:
+            return self.get_xres_client_id(wid)
+
+        return self.get_net_wm_pid(wid)
+
+
+class CGroupHandler:
+    """Main logic: handle i3/sway IPC events and start systemd transient units."""
+
+    def __init__(self, bus: MessageBus, conn: Connection):
+        self._bus = bus
+        self._conn = conn
+        self._xhelper: Optional[XlibHelper] = None
+        try:
+            self._xhelper = XlibHelper()
+        # pylint: disable=broad-except
+        except Exception as exc:
+            LOG.warning("Failed to connect to X11 display: %s", exc)
+
+    async def connect(self):
+        """asynchronous initialization code"""
+        # pylint: disable=attribute-defined-outside-init
+        introspection = await self._bus.introspect(SD_BUS_NAME, SD_OBJECT_PATH)
+        self._sd_proxy = self._bus.get_proxy_object(
+            SD_BUS_NAME, SD_OBJECT_PATH, introspection
+        )
+        self._sd_manager = self._sd_proxy.get_interface(f"{SD_BUS_NAME}.Manager")
+
+        self._compositor_pid = get_pid_by_socket(self._conn.socket_path)
+        self._compositor_cgroup = get_cgroup(self._compositor_pid)
+        assert self._compositor_cgroup is not None
+        LOG.info("compositor:%s %s", self._compositor_pid, self._compositor_cgroup)
+
+        self._conn.on(Event.WINDOW_NEW, self._on_new_window)
+        return self
+
+    def get_pid(self, con: Con) -> Optional[int]:
+        """Get PID from IPC response (sway), X-Resource or _NET_WM_PID (i3)"""
+        if isinstance(con.pid, int) and con.pid > 0:
+            return con.pid
+
+        if con.window is not None and self._xhelper is not None:
+            return self._xhelper.get_window_pid(con.window)
+
+        return None
+
+    def cgroup_change_needed(self, cgroup: Optional[str]) -> bool:
+        """Check criteria for assigning current app into an isolated cgroup"""
+        if cgroup is None:
+            return False
+        for launcher in LAUNCHER_APPS:
+            if SD_SLICE_FORMAT.format(app_id=launcher) in cgroup:
+                return True
+        return cgroup == self._compositor_cgroup
+
+    @retry(
+        reraise=True,
+        retry=retry_if_exception_type(DBusError),
+        stop=stop_after_attempt(3),
+    )
+    async def assign_scope(self, app_id: str, proc: Process):
+        """
+        Assign process (and all unassigned children) to the
+        app-{app_id}.slice/app{app_id}-{pid}.scope cgroup
+        """
+        app_id = escape_app_id(app_id)
+        sd_slice = SD_SLICE_FORMAT.format(app_id=app_id)
+        sd_unit = SD_UNIT_FORMAT.format(app_id=app_id, unique=proc.pid)
+        # Collect child processes as systemd assigns a scope only to explicitly
+        # specified PIDs.
+        # There's a risk of race as the child processes may exit by the time dbus call
+        # reaches systemd, hence the @retry decorator is applied to the method.
+        pids = [proc.pid] + [
+            x.pid
+            for x in proc.children(recursive=True)
+            if self.cgroup_change_needed(get_cgroup(x.pid))
+        ]
+
+        await self._sd_manager.call_start_transient_unit(
+            sd_unit,
+            "fail",
+            [["PIDs", Variant("au", pids)], ["Slice", Variant("s", sd_slice)]],
+            [],
+        )
+        LOG.debug(
+            "window %s successfully assigned to cgroup %s/%s", app_id, sd_slice, sd_unit
+        )
+
+    async def _on_new_window(self, _: Connection, event: Event):
+        """window:new IPC event handler"""
+        con = event.container
+        app_id = con.app_id if con.app_id else con.window_class
+        try:
+            pid = self.get_pid(con)
+            if pid is None:
+                LOG.warning("Failed to get pid for %s", app_id)
+                return
+            proc = Process(pid)
+            cgroup = get_cgroup(proc.pid)
+            # some X11 apps don't set WM_CLASS. fallback to process name
+            if app_id is None:
+                app_id = proc.name()
+            LOG.debug("window %s(%s) cgroup %s", app_id, proc.pid, cgroup)
+            if self.cgroup_change_needed(cgroup):
+                await self.assign_scope(app_id, proc)
+        # pylint: disable=broad-except
+        except Exception:
+            LOG.exception("Failed to modify cgroup for %s", app_id)
+
+
+async def main():
+    """Async entrypoint"""
+    bus = await MessageBus().connect()
+    conn = await Connection(auto_reconnect=False).connect()
+    await CGroupHandler(bus, conn).connect()
+    try:
+        await conn.main()
+    except (ConnectionError, EOFError):
+        logging.exception("Connection to the Sway IPC was lost")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description="Assign CGroups to apps in compositors with i3 IPC protocol support"
+    )
+    parser.add_argument(
+        "-l",
+        "--loglevel",
+        choices=["critical", "error", "warning", "info", "debug"],
+        default="info",
+        dest="loglevel",
+        help="set logging level",
+    )
+    args = parser.parse_args()
+    logging.basicConfig(level=args.loglevel.upper())
+    asyncio.run(main())

.config/sway/bin/session.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+export XDG_CURRENT_DESKTOP=sway
+export XDG_SESSION_TYPE=wayland
+export _JAVA_AWT_WM_NONREPARENTING=1
+VARIABLES="DISPLAY I3SOCK SWAYSOCK WAYLAND_DISPLAY XDG_CURRENT_DESKTOP XDG_SESSION_TYPE _JAVA_AWT_WM_NONREPARENTING"
+SESSION_TARGET="sway-session.target"
+
+if hash dbus-update-activation-environment 2>/dev/null; then
+    dbus-update-activation-environment --systemd $VARIABLES
+fi
+
+systemctl --user import-environment $VARIABLES
+systemctl --user start "$SESSION_TARGET"
+
+if [ "$1" != "--with-cleanup" ] ||
+    [ -z "$SWAYSOCK" ] ||
+    ! hash swaymsg 2>/dev/null
+then
+    exit 0;
+fi
+
+swaymsg -t subscribe '["shutdown"]'
+
+systemctl --user stop "$SESSION_TARGET"
+systemctl --user unset-environment $VARIABLES

.config/sway/sway.d/07-hotkeys.conf

@@ -191,3 +191,8 @@ bindsym $mod+o exec --no-startup-id ~/.config/rofi/scripts/sound.sh
 bindsym $mod+y exec clipman pick  -t rofi
 
 
+bindsym $mod+u exec env RUST_BACKTRACE=1 swayr switch-window >> /tmp/swayr.log 2>&1
+
+bindsym $mod+Tab exec env RUST_BACKTRACE=1 swayr switch-to-urgent-or-lru-window >> /tmp/swayr.log 2>&1
+
+bindsym $mod+$alt+Space exec env RUST_BACKTRACE=1 swayr switch-workspace-or-window >> /tmp/swayr.log 2>&1

.config/sway/sway.d/10-autostart.conf

@@ -11,7 +11,5 @@ exec_always {
     gsettings set org.gnome.desktop.wm.preferences button-layout ''
 }
 
-exec "hash dbus-update-activation-environment 2>/dev/null; \
-     dbus-update-activation-environment --all; \
-     dbus-update-activation-environment --systemd; \
-     systemctl --user start sway-session.target"
+exec ~/.config/sway/bin/session.sh --with-cleanup
+exec ~/.config/sway/bin/assign-cgroups.py