main: Add (optional) systemd notify

Cargo.toml

@@ -25,6 +25,7 @@ indexmap = "1.8.0"
 xdg = "^2.1"
 ron = "0.7"
 atomic_float = "0.1"
+libsystemd = "0.5"
 
 [dependencies.smithay]
 version = "0.3"
@@ -57,3 +58,4 @@ lto = "fat"
 
 [patch."https://github.com/Smithay/smithay.git"]
 smithay = { git = "https://github.com/pop-os/smithay", branch = "main" }
+#smithay = { path = "../smithay" }

data/cosmic-comp.service

@@ -6,7 +6,7 @@ After=cosmic-session-pre.target
 Before=cosmic-session.target
 
 [Service]
-Type=simple
+Type=notify
 ExecStart=/usr/bin/cosmic-comp
 Restart=never
 ExecStopPost=/usr/bin/systemctl --user unset-environment DISPLAY WAYLAND_DISPLAY

src/main.rs

@@ -14,6 +14,7 @@ pub mod input;
 mod logger;
 pub mod shell;
 pub mod state;
+pub mod systemd;
 pub mod utils;
 pub mod wayland;
 
@@ -33,6 +34,8 @@ fn main() -> Result<()> {
     let mut state = state::State::new(display, socket, event_loop.handle(), event_loop.get_signal(), log);
     // init backend
     backend::init_backend_auto(&mut event_loop, &mut state)?;
+    // potentially tell systemd we are setup now
+    systemd::ready(&state);
 
     // run the event loop
     event_loop.run(None, &mut state, |state| {

src/systemd.rs

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use libsystemd::daemon::{booted, notify, NotifyState};
+use std::process::Command;
+use crate::state::State;
+
+pub fn ready(state: &State) {
+    if booted() {
+        match Command::new("systemctl")
+            .args(["--user", "import-environment", "WAYLAND_DISPLAY"])
+            .env("WAYLAND_DISPLAY", &state.common.socket)
+            .status()
+        {
+            Ok(x) if x.success() => {},
+            Ok(x) => slog_scope::warn!("Failed to import WAYLAND_DISPLAY into systemd (exit code {:?})", x.code()),
+            Err(err) => slog_scope::error!("Failed to run systemctl although booted with systemd: {}", err),
+        };
+
+        if let Err(err) = notify(false, &[NotifyState::Ready]) {
+            slog_scope::error!("Failed to notify systemd: {}", err);
+        }
+    }
+}