Isolate nested IPC sockets and define session ownership policy

shell/ferese-polkit-agent/src/main.rs

@@ -221,7 +221,9 @@ async fn session_subject(
     connection: &zbus::Connection,
 ) -> Result<(String, HashMap<String, Value<'static>>), Box<dyn std::error::Error>> {
     // Nested previews must not take over authentication for the host desktop.
-    if std::env::var("FERESE_SESSION_IMPORT_ENV").as_deref() == Ok("0") {
+    if std::env::var("FERESE_SESSION_MODE").as_deref() == Ok("embedded")
+        || std::env::var("FERESE_SESSION_IMPORT_ENV").as_deref() == Ok("0")
+    {
         return process_subject().map_err(Into::into);
     }
     let manager = zbus::Proxy::new(

shell/ferese-settings/src/store.rs

@@ -228,11 +228,10 @@ fn save_with(
 
 pub fn reload_running() -> bool {
     use ferese_ipc::{Request, Response, VERSION, read_frame, write_frame};
-    let Some(runtime) = std::env::var_os("XDG_RUNTIME_DIR") else {
+    let Ok(path) = ferese_ipc::socket::resolve(None) else {
         return false;
     };
-    let Ok(mut socket) = std::os::unix::net::UnixStream::connect(PathBuf::from(runtime).join("ferese/control.sock"))
-    else {
+    let Ok(mut socket) = std::os::unix::net::UnixStream::connect(path) else {
         return false;
     };
     let _ = socket.set_read_timeout(Some(Duration::from_secs(2)));

shell/ferese-shell/src/compositor_ipc.rs

@@ -1,5 +1,4 @@
 use std::os::unix::net::UnixStream;
-use std::path::PathBuf;
 use std::time::{Duration, Instant};
 
 use serde_json::{Value, json};
@@ -15,10 +14,7 @@ struct SessionConnection {
 
 impl SessionConnection {
     fn connect() -> Result<Self, String> {
-        let path = std::env::var_os("XDG_RUNTIME_DIR")
-            .map(PathBuf::from)
-            .ok_or("Missing runtime directory")?
-            .join("ferese/control.sock");
+        let path = ferese_ipc::socket::resolve(None).map_err(|error| error.to_string())?;
         let stream = UnixStream::connect(path).map_err(|error| error.to_string())?;
         stream
             .set_read_timeout(Some(Duration::from_secs(2)))