Add systemd module to talpid-dbus

2 files changed, 68 insertions, 0 deletions

diff --git a/talpid-dbus/src/lib.rs b/talpid-dbus/src/lib.rs
index c4b9bb7e12..f85581864a 100644
--- a/talpid-dbus/src/lib.rs
+++ b/talpid-dbus/src/lib.rs
@@ -4,6 +4,7 @@ pub use dbus;
 use dbus::blocking::SyncConnection;
 use std::sync::{Arc, Mutex};
 pub mod network_manager;
+pub mod systemd;
 pub mod systemd_resolved;
 
 lazy_static::lazy_static! {
diff --git a/talpid-dbus/src/systemd.rs b/talpid-dbus/src/systemd.rs
new file mode 100644
index 0000000000..521f2a1b8e
--- /dev/null
+++ b/talpid-dbus/src/systemd.rs
@@ -0,0 +1,67 @@
+use dbus::blocking::{stdintf::org_freedesktop_dbus::Properties, Proxy, SyncConnection};
+use std::{sync::Arc, time::Duration};
+
+type Result<T> = std::result::Result<T, Error>;
+
+#[derive(err_derive::Error, Debug)]
+#[error(no_from)]
+pub enum Error {
+    #[error(display = "Failed to create a DBus connection")]
+    ConnectError(#[error(source)] dbus::Error),
+
+    #[error(display = "Failed to read SystemState property")]
+    ReadSystemStateError(#[error(source)] dbus::Error),
+}
+
+const SYSTEMD_BUS: &str = "org.freedesktop.systemd1";
+const SYSTEMD_PATH: &str = "/org/freedesktop/systemd1";
+const MANAGER_INTERFACE: &str = "org.freedesktop.systemd1.Manager";
+const SYSTEM_STATE: &str = "SystemState";
+const SYSTEM_STATE_STARTING: &str = "starting";
+const SYSTEM_STATE_INITIALIZING: &str = "initializing";
+const SYSTEM_STATE_RUNNING: &str = "running";
+const SYSTEM_STATE_DEGRADED: &str = "degraded";
+
+const RPC_TIMEOUT: Duration = Duration::from_secs(1);
+
+/// Returns true if the host is not shutting down or entering maintenance mode or some other weird
+/// state.
+pub fn is_host_running() -> Result<bool> {
+    Systemd::new()?.system_is_running()
+}
+
+struct Systemd {
+    pub dbus_connection: Arc<SyncConnection>,
+}
+
+impl Systemd {
+    fn new() -> Result<Self> {
+        Ok(Self {
+            dbus_connection: crate::get_connection().map_err(Error::ConnectError)?,
+        })
+    }
+
+    fn system_is_running(&self) -> Result<bool> {
+        self.as_manager_object()
+            .get(MANAGER_INTERFACE, SYSTEM_STATE)
+            .map(|state: String| {
+                ![
+                    SYSTEM_STATE_STARTING,
+                    SYSTEM_STATE_INITIALIZING,
+                    SYSTEM_STATE_RUNNING,
+                    SYSTEM_STATE_DEGRADED,
+                ]
+                .contains(&state.as_str())
+            })
+            .map_err(Error::ReadSystemStateError)
+    }
+
+    fn as_manager_object(&self) -> Proxy<'_, &SyncConnection> {
+        Proxy::new(
+            SYSTEMD_BUS,
+            SYSTEMD_PATH,
+            RPC_TIMEOUT,
+            &self.dbus_connection,
+        )
+    }
+}