fix: harden fips startup and app port relays

core/archipelago/src/fips/mod.rs

@@ -54,7 +54,8 @@ pub async fn ensure_activated(data_dir: &std::path::Path) {
         tracing::warn!("FIPS auto-activate: config install failed: {:#}", e);
         return;
     }
-    if let Err(e) = service::activate(SERVICE_UNIT).await {
+    let unit = service::activation_unit().await;
+    if let Err(e) = service::activate(unit).await {
         tracing::warn!("FIPS auto-activate: service activate failed: {:#}", e);
         return;
     }

core/archipelago/src/fips/service.rs

@@ -32,6 +32,16 @@ pub async fn unit_state(unit: &str) -> String {
     }
 }
 
+/// Whether systemd knows about `unit`.
+pub async fn unit_exists(unit: &str) -> bool {
+    Command::new("systemctl")
+        .args(["cat", unit])
+        .output()
+        .await
+        .map(|out| out.status.success())
+        .unwrap_or(false)
+}
+
 /// Whether the `fips` debian package is installed on the host.
 pub async fn package_installed() -> bool {
     // dpkg-query -W -f='${Status}' fips → "install ok installed" when present.
@@ -131,17 +141,28 @@ done
     Ok(())
 }
 
-/// Resolve which systemd unit is actually supervising the fips daemon
-/// on this host. Nodes installed from the archipelago ISO run
-/// `archipelago-fips.service`; nodes that were apt-installed (or had
-/// fips running before archipelago took over) may only have the
-/// upstream `fips.service`. Restart/Reconnect must operate on whichever
-/// one is running, otherwise the UI button is a silent no-op.
+/// Resolve which systemd unit should be started when FIPS is inactive.
+/// Newer Archipelago images may ship `archipelago-fips.service`; nodes with
+/// the upstream Debian package may only have `fips.service`. Activation must
+/// choose a unit systemd can actually load, otherwise the dashboard repeatedly
+/// offers an "Activate" action that can never succeed.
+pub async fn activation_unit() -> &'static str {
+    if unit_exists(super::SERVICE_UNIT).await {
+        return super::SERVICE_UNIT;
+    }
+    if unit_exists(super::UPSTREAM_SERVICE_UNIT).await {
+        return super::UPSTREAM_SERVICE_UNIT;
+    }
+    super::SERVICE_UNIT
+}
+
+/// Resolve which systemd unit is actually supervising the fips daemon on this
+/// host. Restart/Reconnect must operate on whichever one is running, otherwise
+/// the UI button is a silent no-op.
 ///
 /// Returns the archipelago-managed unit name if it's active,
 /// else the upstream unit name if that's active,
-/// else the archipelago-managed name as a default (so activate() can
-/// bring it up).
+/// else a startable activation unit.
 pub async fn active_unit() -> &'static str {
     if unit_state(super::SERVICE_UNIT).await == "active" {
         return super::SERVICE_UNIT;
@@ -149,7 +170,7 @@ pub async fn active_unit() -> &'static str {
     if unit_state(super::UPSTREAM_SERVICE_UNIT).await == "active" {
         return super::UPSTREAM_SERVICE_UNIT;
     }
-    super::SERVICE_UNIT
+    activation_unit().await
 }
 
 pub async fn mask(unit: &str) -> Result<()> {
@@ -248,4 +269,10 @@ mod tests {
         // Must not panic regardless of host state.
         let _ = package_installed().await;
     }
+
+    #[tokio::test]
+    async fn test_unit_exists_is_bool() {
+        // Must not panic regardless of host state.
+        let _ = unit_exists("archipelago-bogus-test.service").await;
+    }
 }