Add PID to Window IPC

niri-ipc/src/lib.rs

@@ -695,6 +695,11 @@ pub struct Window {
     pub title: Option<String>,
     /// Application ID, if set.
     pub app_id: Option<String>,
+    /// Process ID that created the Wayland connection for this window, if known.
+    ///
+    /// Currently, windows created by xdg-desktop-portal-gnome will have a `None` PID, but this may
+    /// change in the future.
+    pub pid: Option<i32>,
     /// Id of the workspace this window is on, if any.
     pub workspace_id: Option<u64>,
     /// Whether this window is currently focused.

src/dbus/mutter_service_channel.rs

@@ -30,6 +30,8 @@ impl ServiceChannel {
             // Would be nice to thread config here but for now it's fine.
             can_view_decoration_globals: false,
             restricted: false,
+            // FIXME: maybe you can get the PID from D-Bus somehow?
+            credentials_unknown: true,
         });
         self.display.insert_client(sock2, data).unwrap();
         Ok(unsafe { zbus::zvariant::OwnedFd::from_raw_fd(sock1.into_raw_fd()) })

src/handlers/mod.rs

@@ -410,6 +410,7 @@ impl SecurityContextHandler for State {
                     compositor_state: Default::default(),
                     can_view_decoration_globals: config.prefer_no_csd,
                     restricted: true,
+                    credentials_unknown: false,
                 });
 
                 if let Err(err) = state.niri.display_handle.insert_client(client, data) {

src/ipc/client.rs

@@ -449,6 +449,12 @@ fn print_window(window: &Window) {
         println!("  App ID: (unset)");
     }
 
+    if let Some(pid) = window.pid {
+        println!("  PID: {pid}");
+    } else {
+        println!("  PID: (unknown)");
+    }
+
     if let Some(workspace_id) = window.workspace_id {
         println!("  Workspace ID: {workspace_id}");
     } else {

src/ipc/server.rs

@@ -363,6 +363,7 @@ fn make_ipc_window(mapped: &Mapped, workspace_id: Option<WorkspaceId>) -> niri_i
         id: mapped.id().get(),
         title: role.title.clone(),
         app_id: role.app_id.clone(),
+        pid: mapped.credentials().map(|c| c.pid),
         workspace_id: workspace_id.map(|id| id.get()),
         is_focused: mapped.is_focused(),
     })

src/niri.rs

@@ -1773,6 +1773,7 @@ impl Niri {
                     compositor_state: Default::default(),
                     can_view_decoration_globals: config.prefer_no_csd,
                     restricted: false,
+                    credentials_unknown: false,
                 });
 
                 if let Err(err) = state.niri.display_handle.insert_client(client, data) {
@@ -4825,6 +4826,8 @@ pub struct ClientState {
     pub can_view_decoration_globals: bool,
     /// Whether this client is denied from the restricted protocols such as security-context.
     pub restricted: bool,
+    /// We cannot retrieve this client's socket credentials.
+    pub credentials_unknown: bool,
 }
 
 impl ClientData for ClientState {

src/utils/mod.rs

@@ -16,12 +16,16 @@ use smithay::output::{self, Output};
 use smithay::reexports::rustix::time::{clock_gettime, ClockId};
 use smithay::reexports::wayland_protocols::xdg::shell::server::xdg_toplevel;
 use smithay::reexports::wayland_server::protocol::wl_surface::WlSurface;
+use smithay::reexports::wayland_server::{DisplayHandle, Resource as _};
 use smithay::utils::{Coordinate, Logical, Point, Rectangle, Size, Transform};
 use smithay::wayland::compositor::{send_surface_state, with_states, SurfaceData};
 use smithay::wayland::fractional_scale::with_fractional_scale;
 use smithay::wayland::shell::xdg::{
     ToplevelSurface, XdgToplevelSurfaceData, XdgToplevelSurfaceRoleAttributes,
 };
+use wayland_backend::server::Credentials;
+
+use crate::niri::ClientState;
 
 pub mod id;
 pub mod scale;
@@ -244,6 +248,19 @@ pub fn with_toplevel_role<T>(
     })
 }
 
+pub fn get_credentials_for_surface(surface: &WlSurface) -> Option<Credentials> {
+    let handle = surface.handle().upgrade()?;
+    let dh = DisplayHandle::from(handle);
+
+    let client = dh.get_client(surface.id()).ok()?;
+    let data = client.get_data::<ClientState>().unwrap();
+    if data.credentials_unknown {
+        return None;
+    }
+
+    client.get_credentials(&dh).ok()
+}
+
 #[cfg(feature = "dbus")]
 pub fn show_screenshot_notification(image_path: Option<PathBuf>) {
     let mut notification = notify_rust::Notification::new();

src/window/mapped.rs

@@ -15,7 +15,9 @@ use smithay::reexports::wayland_server::protocol::wl_surface::WlSurface;
 use smithay::reexports::wayland_server::Resource as _;
 use smithay::utils::{Logical, Point, Rectangle, Scale, Serial, Size, Transform};
 use smithay::wayland::compositor::{remove_pre_commit_hook, with_states, HookId};
+use smithay::wayland::seat::WaylandFocus;
 use smithay::wayland::shell::xdg::{SurfaceCachedState, ToplevelSurface};
+use wayland_backend::server::Credentials;
 
 use super::{ResolvedWindowRules, WindowRef};
 use crate::handlers::KdeDecorationsModeState;
@@ -33,7 +35,9 @@ use crate::render_helpers::surface::render_snapshot_from_surface_tree;
 use crate::render_helpers::{BakedBuffer, RenderTarget, SplitElements};
 use crate::utils::id::IdCounter;
 use crate::utils::transaction::Transaction;
-use crate::utils::{send_scale_transform, with_toplevel_role, ResizeEdge};
+use crate::utils::{
+    get_credentials_for_surface, send_scale_transform, with_toplevel_role, ResizeEdge,
+};
 
 #[derive(Debug)]
 pub struct Mapped {
@@ -42,6 +46,9 @@ pub struct Mapped {
     /// Unique ID of this `Mapped`.
     id: MappedId,
 
+    /// Credentials of the process that created the Wayland connection.
+    credentials: Option<Credentials>,
+
     /// Pre-commit hook that we have on all mapped toplevel surfaces.
     pre_commit_hook: HookId,
 
@@ -136,9 +143,13 @@ impl InteractiveResize {
 
 impl Mapped {
     pub fn new(window: Window, rules: ResolvedWindowRules, hook: HookId) -> Self {
+        let surface = window.wl_surface().expect("no X11 support");
+        let credentials = get_credentials_for_surface(&surface);
+
         Self {
             window,
             id: MappedId::next(),
+            credentials,
             pre_commit_hook: hook,
             rules,
             need_to_recompute_rules: false,
@@ -188,6 +199,10 @@ impl Mapped {
         self.id
     }
 
+    pub fn credentials(&self) -> Option<&Credentials> {
+        self.credentials.as_ref()
+    }
+
     pub fn is_focused(&self) -> bool {
         self.is_focused
     }