Fix blocking windows syscalls (#825)

* fix

* build

* Update Cargo.lock

* Delete build-windows-branch.yaml

Author: t-aleksander

src-tauri/Cargo.lock

@@ -15,7 +15,6 @@ use defguard_wireguard_rs::{
 };
 use known_folders::get_known_folder_path;
 use log::{debug, error, warn};
-use tokio::time::sleep;
 use windows::{
     core::PSTR,
     Win32::System::RemoteDesktop::{
@@ -55,7 +54,9 @@ const SERVICE_LOCATIONS_SUBDIR: &str = "service_locations";
 ///
 /// Note: `NotifyAddrChange` also fires when WireGuard interfaces are created. This is
 /// harmless because `connect_to_service_locations` skips already-connected locations.
-pub(crate) async fn watch_for_network_change(
+///
+/// Runs on a dedicated OS thread because `NotifyAddrChange` is a blocking syscall.
+pub(crate) fn watch_for_network_change(
     service_location_manager: Arc<RwLock<ServiceLocationManager>>,
 ) {
     loop {
@@ -65,22 +66,22 @@ pub(crate) async fn watch_for_network_change(
 
         if result != 0 {
             error!("NotifyAddrChange failed with error code: {result}");
-            sleep(NETWORK_CHANGE_MONITOR_RESTART_DELAY).await;
+            std::thread::sleep(NETWORK_CHANGE_MONITOR_RESTART_DELAY);
             continue;
         }
 
         debug!(
             "Network address change detected, waiting {NETWORK_STABILIZATION_DELAY:?}s for \
             network to stabilize before attempting service location connections..."
         );
-        sleep(NETWORK_STABILIZATION_DELAY).await;
+        std::thread::sleep(NETWORK_STABILIZATION_DELAY);
 
         debug!("Attempting to connect to service locations after network change");
-        match service_location_manager
+        let connect_result = service_location_manager
             .write()
             .unwrap()
-            .connect_to_service_locations()
-        {
+            .connect_to_service_locations();
+        match connect_result {
             Ok(_) => {
                 debug!("Service location connect attempt after network change completed");
             }
@@ -91,11 +92,15 @@ pub(crate) async fn watch_for_network_change(
     }
 }
 
-pub(crate) async fn watch_for_login_logoff(
+/// Watches for user logon/logoff events and connects/disconnects pre-logon service locations
+/// accordingly.
+///
+/// Runs on a dedicated OS thread because `WTSWaitSystemEvent` is a blocking syscall.
+pub(crate) fn watch_for_login_logoff(
     service_location_manager: Arc<RwLock<ServiceLocationManager>>,
 ) -> Result<(), ServiceLocationError> {
     loop {
-        let mut event_flags = 0;
+        let mut event_flags: u32 = 0;
         let success = unsafe {
             WTSWaitSystemEvent(
                 Some(WTS_CURRENT_SERVER_HANDLE),
@@ -110,23 +115,21 @@ pub(crate) async fn watch_for_login_logoff(
             }
             Err(err) => {
                 error!("Failed waiting for login/logoff event: {err:?}");
-                sleep(Duration::from_secs(LOGIN_LOGOFF_EVENT_RETRY_DELAY_SECS)).await;
+                std::thread::sleep(Duration::from_secs(LOGIN_LOGOFF_EVENT_RETRY_DELAY_SECS));
                 continue;
             }
         };
 
         if event_flags & WTS_EVENT_LOGON != 0 {
             debug!("Detected user logon, attempting to auto-disconnect from service locations.");
             service_location_manager
-                .clone()
                 .write()
                 .unwrap()
                 .disconnect_service_locations(Some(ServiceLocationMode::PreLogon))?;
         }
         if event_flags & WTS_EVENT_LOGOFF != 0 {
             debug!("Detected user logoff, attempting to auto-connect to service locations.");
             service_location_manager
-                .clone()
                 .write()
                 .unwrap()
                 .connect_to_service_locations()?;
@@ -281,7 +284,11 @@ pub(crate) fn is_user_logged_in() -> bool {
                                         buffer.0 as *mut _,
                                     );
 
-                                    // We found an active session with a username
+                                    // We found an active session with a username.
+                                    // Free the session list before returning to avoid a leak.
+                                    windows::Win32::System::RemoteDesktop::WTSFreeMemory(
+                                        pp_sessions as _,
+                                    );
                                     return true;
                                 }
                             }

src-tauri/src/enterprise/service_locations/windows.rs

@@ -115,17 +115,19 @@ fn run_service() -> Result<(), DaemonError> {
 
         let service_location_manager = Arc::new(RwLock::new(service_location_manager));
 
-        // Spawn network change monitoring task first so NotifyAddrChange is registered as early
-        // as possible, minimising the window in which a network event could be missed before
-        // the watcher is listening. The retry task below is the backstop for any event that
-        // still slips through that window.
+        // Spawn network change monitoring on a dedicated OS thread so the blocking
+        // NotifyAddrChange syscall does not stall Tokio's async worker threads.
+        // Register it first so no network event can be missed before the watcher is listening;
+        // the retry loop below is the backstop for any event that slips through the startup window.
         let service_location_manager_clone = service_location_manager.clone();
-        runtime.spawn(async move {
-            let manager = service_location_manager_clone;
-            info!("Starting network change monitoring");
-            watch_for_network_change(manager.clone()).await;
-            error!("Network change monitoring ended unexpectedly.");
-        });
+        std::thread::Builder::new()
+            .name("network-change-monitor".to_string())
+            .spawn(move || {
+                info!("Starting network change monitoring");
+                watch_for_network_change(service_location_manager_clone);
+                error!("Network change monitoring ended unexpectedly.");
+            })
+            .expect("Failed to spawn network change monitor thread");
 
         // Spawn service location auto-connect task with retries.
         // Each attempt skips locations that are already connected, so it is safe to call
@@ -174,32 +176,34 @@ fn run_service() -> Result<(), DaemonError> {
             info!("Service location auto-connect task finished");
         });
 
-        // Spawn login/logoff monitoring task, runs concurrently with the tasks above.
+        // Spawn login/logoff monitoring on a dedicated OS thread so the blocking
+        // WTSWaitSystemEvent syscall does not stall Tokio's async worker threads.
         let service_location_manager_clone = service_location_manager.clone();
-        runtime.spawn(async move {
-            let manager = service_location_manager_clone;
-
-            info!("Starting login/logoff event monitoring");
-            loop {
-                match watch_for_login_logoff(manager.clone()).await {
-                    Ok(()) => {
-                        warn!(
-                            "Login/logoff event monitoring ended unexpectedly. Restarting in \
-                            {LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS:?}..."
-                        );
-                        sleep(LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS).await;
-                    }
-                    Err(e) => {
-                        error!(
-                            "Error in login/logoff event monitoring: {e}. Restarting in \
-                            {LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS:?}...",
-                        );
-                        sleep(LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS).await;
-                        info!("Restarting login/logoff event monitoring");
+        std::thread::Builder::new()
+            .name("login-logoff-monitor".to_string())
+            .spawn(move || {
+                info!("Starting login/logoff event monitoring");
+                loop {
+                    match watch_for_login_logoff(service_location_manager_clone.clone()) {
+                        Ok(()) => {
+                            warn!(
+                                "Login/logoff event monitoring ended unexpectedly. Restarting in \
+                                {LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS:?}..."
+                            );
+                            std::thread::sleep(LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS);
+                        }
+                        Err(e) => {
+                            error!(
+                                "Error in login/logoff event monitoring: {e}. Restarting in \
+                                {LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS:?}...",
+                            );
+                            std::thread::sleep(LOGIN_LOGOFF_MONITORING_RESTART_DELAY_SECS);
+                            info!("Restarting login/logoff event monitoring");
+                        }
                     }
                 }
-            }
-        });
+            })
+            .expect("Failed to spawn login/logoff monitor thread");
 
         // Spawn the main gRPC server task
         let service_location_manager_clone = service_location_manager.clone();