Started on Virt Manager.
This is a new service to manage crosvm instances running VMs. It
provides an AIDL interface which other services can call to start a VM
with some given configuration.
Bug: 171278952
Test: mm
Change-Id: Ie5b10d5f48da430aaeb66af9f2ee082f143472ec
diff --git a/virtmanager/src/main.rs b/virtmanager/src/main.rs
new file mode 100644
index 0000000..7b0423b
--- /dev/null
+++ b/virtmanager/src/main.rs
@@ -0,0 +1,185 @@
+// Copyright 2021, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Android Virt Manager
+
+use android_system_virtmanager::aidl::android::system::virtmanager::IVirtManager::{
+ BnVirtManager, IVirtManager,
+};
+use android_system_virtmanager::aidl::android::system::virtmanager::IVirtualMachine::{
+ BnVirtualMachine, IVirtualMachine,
+};
+use android_system_virtmanager::binder::{self, add_service, Interface, StatusCode};
+use anyhow::{Context, Error};
+use log::{debug, error, info};
+use serde::{Deserialize, Serialize};
+use std::fs::File;
+use std::io::{self, BufReader};
+use std::process::{Child, Command};
+use std::sync::{Arc, Mutex};
+
+/// The first CID to assign to a guest VM managed by the Virt Manager. CIDs lower than this are
+/// reserved for the host or other usage.
+const FIRST_GUEST_CID: Cid = 10;
+
+const BINDER_SERVICE_IDENTIFIER: &str = "android.system.virtmanager";
+
+/// The unique ID of a VM used (together with a port number) for vsock communication.
+type Cid = u32;
+
+/// Configuration for a particular VM to be started.
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
+struct VmConfig {
+ kernel: String,
+ initrd: Option<String>,
+ params: Option<String>,
+}
+
+fn main() {
+ env_logger::init();
+ let state = Arc::new(Mutex::new(State::new()));
+ let virt_manager = VirtManager::new(state);
+ let virt_manager = BnVirtManager::new_binder(virt_manager);
+ add_service(BINDER_SERVICE_IDENTIFIER, virt_manager.as_binder()).unwrap();
+ info!("Registered Binder service, joining threadpool.");
+ binder::ProcessState::join_thread_pool();
+}
+
+#[derive(Debug)]
+struct VirtManager {
+ state: Arc<Mutex<State>>,
+}
+
+impl VirtManager {
+ fn new(state: Arc<Mutex<State>>) -> Self {
+ VirtManager { state }
+ }
+}
+
+impl Interface for VirtManager {}
+
+impl IVirtManager for VirtManager {
+ /// Create and start a new VM with the given configuration, assigning it the next available CID.
+ ///
+ /// Returns a binder `IVirtualMachine` object referring to it, as a handle for the client.
+ fn startVm(&self, config_path: &str) -> binder::Result<Box<dyn IVirtualMachine>> {
+ let state = &mut *self.state.lock().unwrap();
+ let cid = state.next_cid;
+ let child = start_vm(config_path, cid)?;
+ // TODO(qwandor): keep track of which CIDs are currently in use so that we can reuse them.
+ state.next_cid = state.next_cid.checked_add(1).ok_or(StatusCode::UNKNOWN_ERROR)?;
+ Ok(VirtualMachine::create(Arc::new(VmInstance::new(child, cid))))
+ }
+}
+
+/// Implementation of the AIDL IVirtualMachine interface. Used as a handle to a VM.
+#[derive(Debug)]
+struct VirtualMachine {
+ instance: Arc<VmInstance>,
+}
+
+impl VirtualMachine {
+ fn create(instance: Arc<VmInstance>) -> Box<dyn IVirtualMachine> {
+ let binder = VirtualMachine { instance };
+ Box::new(BnVirtualMachine::new_binder(binder))
+ }
+}
+
+impl Interface for VirtualMachine {}
+
+impl IVirtualMachine for VirtualMachine {
+ fn getCid(&self) -> binder::Result<i32> {
+ Ok(self.instance.cid as i32)
+ }
+}
+
+/// Information about a particular instance of a VM which is running.
+#[derive(Debug)]
+struct VmInstance {
+ /// The crosvm child process.
+ child: Child,
+ /// The CID assigned to the VM for vsock communication.
+ cid: Cid,
+}
+
+impl VmInstance {
+ /// Create a new `VmInstance` with a single reference for the given process.
+ fn new(child: Child, cid: Cid) -> VmInstance {
+ VmInstance { child, cid }
+ }
+}
+
+impl Drop for VmInstance {
+ fn drop(&mut self) {
+ debug!("Dropping {:?}", self);
+ // TODO: Talk to crosvm to shutdown cleanly.
+ if let Err(e) = self.child.kill() {
+ error!("Error killing crosvm instance: {}", e);
+ }
+ // We need to wait on the process after killing it to avoid zombies.
+ match self.child.wait() {
+ Err(e) => error!("Error waiting for crosvm instance to die: {}", e),
+ Ok(status) => info!("Crosvm exited with status {}", status),
+ }
+ }
+}
+
+/// The mutable state of the Virt Manager. There should only be one instance of this struct.
+#[derive(Debug)]
+struct State {
+ next_cid: Cid,
+}
+
+impl State {
+ fn new() -> Self {
+ State { next_cid: FIRST_GUEST_CID }
+ }
+}
+
+/// Start a new VM instance from the given VM config filename. This assumes the VM is not already
+/// running.
+fn start_vm(config_path: &str, cid: Cid) -> binder::Result<Child> {
+ let config = load_vm_config(config_path).map_err(|e| {
+ error!("Failed to load VM config {}: {:?}", config_path, e);
+ StatusCode::BAD_VALUE
+ })?;
+ Ok(run_vm(&config, cid).map_err(|e| {
+ error!("Failed to start VM {}: {:?}", config_path, e);
+ StatusCode::UNKNOWN_ERROR
+ })?)
+}
+
+/// Load the configuration for the VM with the given ID from a JSON file.
+fn load_vm_config(path: &str) -> Result<VmConfig, Error> {
+ let file = File::open(path).with_context(|| format!("Failed to open {}", path))?;
+ let buffered = BufReader::new(file);
+ Ok(serde_json::from_reader(buffered)?)
+}
+
+/// Start an instance of `crosvm` to manage a new VM.
+fn run_vm(config: &VmConfig, cid: Cid) -> Result<Child, io::Error> {
+ let mut command = Command::new("crosvm");
+ // TODO(qwandor): Remove --disable-sandbox.
+ command.arg("run").arg("--disable-sandbox").arg("--cid").arg(cid.to_string());
+ if let Some(initrd) = &config.initrd {
+ command.arg("--initrd").arg(initrd);
+ }
+ if let Some(params) = &config.params {
+ command.arg("--params").arg(params);
+ }
+ command.arg(&config.kernel);
+ info!("Running {:?}", command);
+ // TODO: Monitor child process, and remove from VM map if it dies.
+ command.spawn()
+}