Fix systemd stopping notif, vendor sd_notify

Cargo.toml

@@ -143,9 +143,6 @@ features = ["tokio-runtime"]
 version = "2.1.1"
 features = ["serde"]
 
-[target.'cfg(unix)'.dependencies]
-sd-notify = "0.4.0"
-
 # Per `rsa` crate docs, significantly speeds up key generation for debug builds.
 [profile.dev.package.num-bigint-dig]
 opt-level = 3

src/main.rs

@@ -219,8 +219,9 @@ async fn start_server(builder: ConfigBuilder) {
     let mut connections = JoinSet::new();
 
     #[cfg(unix)]
-    sd_notify::notify(true, &[sd_notify::NotifyState::Ready])
-        .expect("Failed to signal ready to the service manager");
+    let sd_notify = utils::SdNotify::new();
+    #[cfg(unix)]
+    sd_notify.notify_ready();
 
     // Snippet for the connection loop with graceful shutdown.
     // This is shared between TCP and Unix socket code.
@@ -281,9 +282,8 @@ async fn start_server(builder: ConfigBuilder) {
     }
 
     #[cfg(unix)]
-    if let Err(err) = sd_notify::notify(true, &[sd_notify::NotifyState::Stopping]) {
-        log::error!("Failed to signal stopping to the service manager: {}", err);
-    }
+    sd_notify.notify_stopping();
+
     while connections.join_next().await.is_some() {}
     log::info!("Shutdown complete");
 }

src/utils/mod.rs

@@ -20,5 +20,10 @@ pub use real_ip::*;
 pub use rng::*;
 pub use time::*;
 
+#[cfg(unix)]
+mod sd_notify;
+#[cfg(unix)]
+pub use sd_notify::*;
+
 pub type BoxError = Box<dyn Error + Send + Sync>;
 pub type BoxFuture<T> = Pin<Box<dyn Future<Output = T> + Send>>;

src/utils/sd_notify.rs

@@ -0,0 +1,41 @@
+use std::{env, ffi::OsString, io, os::unix::net::UnixDatagram};
+
+// Sends state notifications to systemd.
+//
+// Based on https://github.com/lnicola/sd-notify (MIT/Apache-2.0)
+pub struct SdNotify {
+    path: Option<OsString>,
+}
+
+impl SdNotify {
+    pub fn new() -> Self {
+        let path = env::var_os("NOTIFY_SOCKET");
+        env::remove_var("NOTIFY_SOCKET");
+        Self { path }
+    }
+
+    pub fn notify_ready(&self) {
+        self.send(b"READY=1\n")
+            .expect("Failed to signal ready to the service manager");
+    }
+
+    pub fn notify_stopping(&self) {
+        if let Err(err) = self.send(b"STOPPING=1\n") {
+            log::error!("Failed to signal stopping to the service manager: {err}");
+        }
+    }
+
+    fn send(&self, msg: &[u8]) -> io::Result<()> {
+        let Some(path) = self.path.as_ref() else {
+            return Ok(());
+        };
+
+        let sock = UnixDatagram::unbound()?;
+        let len = sock.send_to(msg, path)?;
+        if len != msg.len() {
+            return Err(io::Error::new(io::ErrorKind::WriteZero, "incomplete write"));
+        }
+
+        Ok(())
+    }
+}