qmp: add utility to execute hmp commands

Mostly for ease of use and later usage.

src/main.rs

@@ -25,6 +25,9 @@ async fn main() {
 
     println!("Connected to QMP server");
 
+
+    println!("res {}", client.execute_hmp("info block".into()).await.expect("this shouldn't fail"));
+
     // let's try to get all STOP events from QMP now.
     let mut rx = client.subscribe_to_event("STOP".into()).await.unwrap();
 

src/qmp/actor.rs

@@ -217,8 +217,7 @@ where
 		let (tx, rx) = mpsc::channel(8);
 		let inner = QmpClientActor::new(socket, rx);
 		tokio::spawn(async move { 
-			let res = inner.run().await;
-			res.inspect_err(|err| {
+			inner.run().await.inspect_err(|err| {
 				tracing::error!("error in actor runloop: {err}");
 			});
 		 });

src/qmp/client.rs

@@ -1,5 +1,6 @@
 //! QMP client.
 
+use serde_json::json;
 use tokio::{
 	io::{AsyncReadExt, AsyncWriteExt},
 	sync::{mpsc, oneshot},
@@ -35,6 +36,16 @@ impl QmpClient {
 
 	// TODO handle errors properly
 
+	/// Closes this client.
+	pub async fn close(&self) -> result::Result<()> {
+		let _ = self
+			.tx
+			.send(actor::QmpActorMessage::QmpDoClose { })
+			.await;
+		Ok(())
+	}
+
+	/// Handshakes QMP with the server. This **MUST** be the first operation you do.
 	pub async fn handshake(&self) -> result::Result<types::QmpHandshake> {
 		let (tx, rx) = oneshot::channel();
 
@@ -48,7 +59,10 @@ impl QmpClient {
 		}
 	}
 
+	// FIXME: QMP errors should bubble out into an Rust error,
+	// for now this isn't done.
 
+	/// Executes a single QMP command.
 	pub async fn execute(&self, command: String, arguments: Option<serde_json::Value>) -> result::Result<serde_json::Value> {
 		let (tx, rx) = oneshot::channel();
 
@@ -62,7 +76,18 @@ impl QmpClient {
 			Err(err) => Err(result::QmpError::GeneralFail),
 		}
 	}
-	/// Subscribes to a QMP event.
+
+	/// Executes a HMP (QEMU Monitor) command.
+	pub async fn execute_hmp(&self, hmp_line: String) -> result::Result<String> {
+		let res = self.execute("human-monitor-command".into(), Some(json!({
+			"command-line": hmp_line
+		}))).await?;
+
+		// This is very nasty, but this is always a string.
+		Ok(String::from(res["return"].as_str().unwrap()))
+	}
+
+	/// Subscribes to a QMP event with the given event name.
 	/// Returns the recvieving arm of a [mpsc::channel] which will recieve
 	/// the JSON event payloads when an event is sent by the server.
 	pub async fn subscribe_to_event(