main: Add (optional) systemd notify

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);
+        }
+    }
+}