chore: put systemd-homed extra support behind 'systemd' feature

daemon/Cargo.toml

@@ -28,8 +28,8 @@ whitespace-conf = "1"
 #TODO: reduce features
 tokio = { workspace = true, features = ["full"] }
 xdg = "3.0"
-zbus_systemd = { version = "0.26000.0", features = ["home1"] }
+zbus_systemd = { version = "0.26000.0", features = ["home1"], optional = true }
 
 [features]
 default = ["systemd"]
-systemd = ["tracing-journald"]
+systemd = ["tracing-journald", "zbus_systemd"]

daemon/src/lib.rs

@@ -7,7 +7,6 @@ use std::io::Read;
 use std::os::unix::fs::OpenOptionsExt;
 use std::path::{Path, PathBuf};
 use zbus::Connection;
-use zbus_systemd::home1::ManagerProxy;
 
 pub use cosmic_applets_config::time::TimeAppletConfig;
 pub use cosmic_bg_config::state::State as BgState;
@@ -22,12 +21,12 @@ pub struct UserFilter {
 }
 
 impl UserFilter {
-    pub async fn new() -> Result<Self, zbus::Error> {
-        let login_defs_data = fs::read_to_string("/etc/login.defs").unwrap_or_default();
-        let login_defs = whitespace_conf::parse(&login_defs_data);
+    #[cfg(feature = "systemd")]
+    async fn get_homed_uids() -> Result<BTreeSet<u32>, zbus::Error> {
+        use zbus_systemd::home1;
 
         let connection = Connection::system().await?;
-        let homed = ManagerProxy::new(&connection).await?;
+        let homed = home1::ManagerProxy::new(&connection).await?;
 
         let homed_uids = homed
             .list_homes()
@@ -36,7 +35,24 @@ impl UserFilter {
             .map(|(_, uid, ..)| *uid)
             .collect();
 
-        Ok(Self {
+        Ok(homed_uids)
+    }
+
+    pub async fn new() -> Self {
+        let login_defs_data = fs::read_to_string("/etc/login.defs").unwrap_or_default();
+        let login_defs = whitespace_conf::parse(&login_defs_data);
+
+        #[cfg(feature = "systemd")]
+        let homed_uids = Self::get_homed_uids()
+            .await
+            .inspect_err(|e| {
+                tracing::warn!("failed to list dynamic UIDs from systemd-homed: {e:?}")
+            })
+            .unwrap_or_default();
+        #[cfg(not(feature = "systemd"))]
+        let homed_uids = BTreeSet::new();
+
+        Self {
             uid_min: login_defs
                 .get("UID_MIN")
                 .and_then(|x| x.parse::<u32>().ok())
@@ -46,7 +62,7 @@ impl UserFilter {
                 .and_then(|x| x.parse::<u32>().ok())
                 .unwrap_or(65000),
             homed_uids,
-        })
+        }
     }
 
     pub fn filter(&self, user: &pwd::Passwd) -> bool {

daemon/src/main.rs

@@ -71,7 +71,7 @@ struct GreeterProxy;
 #[zbus::interface(name = "com.system76.CosmicGreeter")]
 impl GreeterProxy {
     async fn get_user_data(&mut self) -> Result<String, GreeterError> {
-        let user_filter = UserFilter::new().await?;
+        let user_filter = UserFilter::new().await;
 
         // The pwd::Passwd method is unsafe (but not labelled as such) due to using global state (libc pwent functions).
         // To prevent issues, this should only be called once in the entire process space at a time