Restructure SIGTERM signalling logic for Unix

src/main.rs

@@ -12,6 +12,7 @@ pub(crate) mod cli;
 pub(crate) mod config;
 pub(crate) mod mc;
 pub(crate) mod monitor;
+pub(crate) mod os;
 pub(crate) mod proto;
 pub(crate) mod proxy;
 pub(crate) mod server;

src/os/mod.rs

@@ -0,0 +1,20 @@
+#[cfg(unix)]
+pub mod unix;
+
+/// Gracefully kill process.
+///
+/// # Panics
+///
+/// Panics on platforms other than Unix.
+#[allow(unreachable_code)]
+pub fn kill_gracefully(pid: u32) {
+    #[cfg(unix)]
+    unsafe {
+        unix::kill_gracefully(pid);
+        return;
+    }
+
+    unimplemented!(
+        "gracefully killing Minecraft server process not implemented on non-Unix platforms"
+    );
+}

src/os/unix.rs

@@ -0,0 +1,11 @@
+/// Gracefully kill process on Unix by sending SIGTERM.
+///
+/// This is unsafe because the PID isn't checked.
+pub unsafe fn kill_gracefully(pid: u32) {
+    debug!(target: "lazymc", "Sending SIGTERM signal to {} to kill server", pid);
+    let result = libc::kill(pid as i32, libc::SIGTERM);
+    trace!(target: "lazymc", "SIGTERM result: {}", result);
+
+    // TODO: send sigterm to childs as well?
+    // TODO: handle error if result != 0
+}

src/server.rs

@@ -64,7 +64,7 @@ impl ServerState {
     pub fn kill_server(&self) -> bool {
         if let Some(pid) = *self.pid.lock().unwrap() {
             debug!(target: "lazymc", "Sending kill signal to server");
-            kill_gracefully(pid);
+            crate::os::unix::kill_gracefully(pid);
 
             // TODO: should we set this?
             self.set_online(false);