From 89e4f1a23dbca42c3aae62ef12dc858d4f61c1b5 Mon Sep 17 00:00:00 2001
From: Alex Zenla <alex@edera.dev>
Date: Fri, 23 Feb 2024 05:26:32 +0000
Subject: [PATCH] controller: implement automatic exit when process has exited

---
 controller/src/console.rs     |  6 ++---
 controller/src/ctl/console.rs | 29 +++++++++++++++++++---
 libs/xen/xenstore/src/bus.rs  | 45 ++++-------------------------------
 3 files changed, 34 insertions(+), 46 deletions(-)

diff --git a/controller/src/console.rs b/controller/src/console.rs
index 3177eb3..f487c3e 100644
--- a/controller/src/console.rs
+++ b/controller/src/console.rs
@@ -5,7 +5,7 @@ use std::{
 
 use anyhow::Result;
 use futures::future::join_all;
-use log::warn;
+use log::debug;
 use std::process::exit;
 use termion::raw::IntoRawMode;
 use tokio::{
@@ -34,7 +34,7 @@ impl XenConsole {
         let stdout = unsafe { File::from_raw_fd(terminal.as_raw_fd()) };
         let reader_task = tokio::task::spawn(async move {
             if let Err(error) = XenConsole::copy_stdout(stdout, self.xen_read_handle).await {
-                warn!("failed to copy console output: {}", error);
+                debug!("failed to copy console output: {}", error);
             }
         });
         let writer_task = tokio::task::spawn(async move {
@@ -44,7 +44,7 @@ impl XenConsole {
             )
             .await
             {
-                warn!("failed to intercept stdin: {}", error);
+                debug!("failed to intercept stdin: {}", error);
             }
         });
 
diff --git a/controller/src/ctl/console.rs b/controller/src/ctl/console.rs
index 3a84d62..d162ab3 100644
--- a/controller/src/ctl/console.rs
+++ b/controller/src/ctl/console.rs
@@ -1,5 +1,11 @@
-use anyhow::{anyhow, Result};
+use std::{process::exit, time::Duration};
 
+use anyhow::{anyhow, Result};
+use log::warn;
+use tokio::time::sleep;
+use xenstore::client::XsdInterface;
+
+use super::destroy::ControllerDestroy;
 use crate::console::XenConsole;
 
 use super::ControllerContext;
@@ -22,7 +28,24 @@ impl ControllerConsole<'_> {
         let domid = info.domid;
         let tty = self.context.xen.get_console_path(domid).await?;
         let console = XenConsole::new(&tty).await?;
-        console.attach().await?;
-        Ok(())
+
+        let dom_path = self.context.xen.store.get_domain_path(domid).await?;
+
+        tokio::task::spawn(async move {
+            if let Err(error) = console.attach().await {
+                warn!("failed to attach to console: {}", error);
+            }
+        });
+
+        let exit_code_path = format!("{}/krata/guest/exit-code", dom_path);
+        loop {
+            let Some(code) = self.context.xen.store.read_string(&exit_code_path).await? else {
+                sleep(Duration::from_secs(1)).await;
+                continue;
+            };
+            let mut destroy = ControllerDestroy::new(self.context);
+            destroy.perform(&domid.to_string()).await?;
+            exit(code.parse::<i32>()?);
+        }
     }
 }
diff --git a/libs/xen/xenstore/src/bus.rs b/libs/xen/xenstore/src/bus.rs
index fd1a5ad..a69d679 100644
--- a/libs/xen/xenstore/src/bus.rs
+++ b/libs/xen/xenstore/src/bus.rs
@@ -1,14 +1,11 @@
 use crate::error::{Error, Result};
 use crate::sys::{XsdMessageHeader, XSD_ERROR};
 use std::ffi::CString;
-use std::fs::{self, metadata, File};
+use std::fs::{metadata, File};
 use std::io::{Read, Write};
 use std::mem::size_of;
-use std::os::unix::fs::FileTypeExt;
-use tokio::io::{AsyncReadExt, AsyncWriteExt};
-use tokio::net::UnixStream;
 
-const XEN_BUS_PATHS: &[&str] = &["/dev/xen/xenbus", "/var/run/xenstored/socket"];
+const XEN_BUS_PATHS: &[&str] = &["/dev/xen/xenbus"];
 
 fn find_bus_path() -> Option<String> {
     for path in XEN_BUS_PATHS {
@@ -20,37 +17,16 @@ fn find_bus_path() -> Option<String> {
     None
 }
 
-#[async_trait::async_trait]
-trait XsdTransport {
-    async fn xsd_write_all(&mut self, buf: &[u8]) -> Result<()>;
-    async fn xsd_read_exact(&mut self, buf: &mut [u8]) -> Result<()>;
-}
-
-#[async_trait::async_trait]
-impl XsdTransport for UnixStream {
-    async fn xsd_write_all(&mut self, buf: &[u8]) -> Result<()> {
-        Ok(self.write_all(buf).await?)
-    }
-
-    async fn xsd_read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
-        self.read_exact(buf).await?;
-        Ok(())
-    }
-}
-
 pub struct XsdFileTransport {
     handle: File,
 }
 
 impl XsdFileTransport {
-    pub fn new(path: &str) -> Result<XsdFileTransport> {
+    fn new(path: &str) -> Result<XsdFileTransport> {
         let handle = File::options().read(true).write(true).open(path)?;
         Ok(XsdFileTransport { handle })
     }
-}
 
-#[async_trait::async_trait]
-impl XsdTransport for XsdFileTransport {
     async fn xsd_read_exact(&mut self, buf: &mut [u8]) -> Result<()> {
         Ok(self.handle.read_exact(buf)?)
     }
@@ -63,7 +39,7 @@ impl XsdTransport for XsdFileTransport {
 }
 
 pub struct XsdSocket {
-    handle: Box<dyn XsdTransport>,
+    handle: XsdFileTransport,
 }
 
 #[derive(Debug)]
@@ -103,19 +79,8 @@ impl XsdSocket {
             Some(path) => path,
             None => return Err(Error::BusNotFound),
         };
-
-        let metadata = fs::metadata(&path)?;
-        let file_type = metadata.file_type();
-        if file_type.is_socket() {
-            let stream = UnixStream::connect(&path).await?;
-            return Ok(XsdSocket {
-                handle: Box::new(stream),
-            });
-        }
         let transport = XsdFileTransport::new(&path)?;
-        Ok(XsdSocket {
-            handle: Box::new(transport),
-        })
+        Ok(XsdSocket { handle: transport })
     }
 
     pub async fn send(&mut self, tx: u32, typ: u32, buf: &[u8]) -> Result<XsdResponse> {