✨ Add start-cosmic script; cosmic-session.target

Justfile

@@ -10,6 +10,7 @@ debug_args := if debug == '1' { '' } else { '--release' }
 cargo_args := vendor_args + ' ' + debug_args
 
 bindir := prefix + '/bin'
+systemddir := prefix + '/lib/systemd/user'
 sessiondir := prefix + '/share/wayland-sessions'
 
 all: _extract_vendor
@@ -23,6 +24,12 @@ install:
 	# session desktop file
 	install -Dm0644 data/cosmic.desktop {{sessiondir}}/cosmic.desktop
 
+	# session start script
+	install -Dm0755 data/start-cosmic {{bindir}}/start-cosmic
+	
+	# systemd target
+	install -Dm0644 data/cosmic-session.target {{systemddir}}/cosmic-session.target
+
 clean_vendor:
 	rm -rf vendor vendor.tar .cargo/config
 

data/cosmic-session.target

@@ -0,0 +1,5 @@
+[Unit]
+Description=Cosmic Session Target
+Documentation=man:systemd.special(7)
+BindsTo=graphical-session.target
+Before=graphical-session.target

data/cosmic.desktop

@@ -1,7 +1,7 @@
 [Desktop Entry]
 Name=COSMIC
 Comment=This session logs you into the COSMIC desktop
-Exec=/usr/bin/dbus-run-session -- /usr/bin/cosmic-session
-TryExec=/usr/bin/cosmic-session
+Exec=/usr/bin/start-cosmic
+TryExec=/usr/bin/start-cosmic
 Type=Application
 DesktopNames=pop:COSMIC

data/start-cosmic

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+# From: https://people.debian.org/~mpitt/systemd.conf-2016-graphical-session.pdf
+
+# robustness: if the previous graphical session left some failed units,
+# reset them so that they don't break this startup
+for unit in $(systemctl --user --no-legend --state=failed --plain list-units | cut -f1 -d' '); do
+    partof="$(systemctl --user show -p PartOf --value "$unit")"
+    for target in cosmic-session.target graphical-session.target; do
+        if [ "$partof" = "$target" ]; then
+            systemctl --user reset-failed "$unit"
+            break
+        fi
+    done
+done
+
+# /etc/profile contains a lot of important environment variables
+source /etc/profile
+
+export XDG_CURRENT_DESKTOP="${XDG_CURRENT_DESKTOP:=pop:COSMIC}"
+export XDG_SESSION_TYPE="${XDG_SESSION_TYPE:=wayland}"
+export XCURSOR_THEME="${XCURSOR_THEME:=Adwaita}"
+
+# import environment variables from the login manager
+systemctl --user import-environment XDG_SESSION_TYPE XDG_CURRENT_DESKTOP
+
+# Run cosmic-session
+exec /usr/bin/dbus-run-session -- /usr/bin/cosmic-session

src/main.rs

@@ -5,6 +5,7 @@ extern crate tracing;
 mod comp;
 mod generic;
 mod process;
+mod systemd;
 
 use async_signals::Signals;
 use color_eyre::{eyre::WrapErr, Result};
@@ -37,6 +38,9 @@ async fn main() -> Result<()> {
 	if let Err(err) = comp::run_compositor(token.child_token(), socket_rx, env_tx) {
 		error!("compositor errored: {:?}", err);
 	}
+	systemd::start_systemd_target()
+		.await
+		.wrap_err("failed to start systemd target")?;
 	let env_vars = env_rx
 		.await
 		.expect("failed to receive environmental variables")

src/systemd.rs

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use color_eyre::{
+	eyre::{eyre, WrapErr},
+	Result,
+};
+use tokio::process::Command;
+
+pub async fn start_systemd_target() -> Result<()> {
+	let output = Command::new("systemctl")
+		.arg("--user")
+		.arg("start")
+		.arg("cosmic-session.target")
+		.spawn()
+		.wrap_err("failed to start systemd target")?
+		.wait()
+		.await
+		.wrap_err("failed to wait for systemd target to start")?;
+
+	if output.success() {
+		Ok(())
+	} else {
+		Err(eyre!(
+			"failed to start systemd target: code {}",
+			output.code().unwrap_or(-1),
+		))
+	}
+}