Add method to get list of VMs for vm tool.
Bug: 181869875
Test: Ran on VIM3L
Change-Id: I90506962171d6c16469e265521b435bec905e0f4
diff --git a/virtmanager/aidl/android/system/virtmanager/IVirtManager.aidl b/virtmanager/aidl/android/system/virtmanager/IVirtManager.aidl
index ade8717..a401fe6 100644
--- a/virtmanager/aidl/android/system/virtmanager/IVirtManager.aidl
+++ b/virtmanager/aidl/android/system/virtmanager/IVirtManager.aidl
@@ -16,8 +16,15 @@
package android.system.virtmanager;
import android.system.virtmanager.IVirtualMachine;
+import android.system.virtmanager.VirtualMachineDebugInfo;
interface IVirtManager {
- /** Start the VM with the given config file, and return a handle to it. */
- IVirtualMachine startVm(String configPath);
+ /** Start the VM with the given config file, and return a handle to it. */
+ IVirtualMachine startVm(String configPath);
+
+ /**
+ * Get a list of all currently running VMs. This method is only intended for debug purposes,
+ * and as such is only permitted from the shell user.
+ */
+ VirtualMachineDebugInfo[] debugListVms();
}
diff --git a/virtmanager/aidl/android/system/virtmanager/IVirtualMachine.aidl b/virtmanager/aidl/android/system/virtmanager/IVirtualMachine.aidl
index 5f408f8..0358bfd 100644
--- a/virtmanager/aidl/android/system/virtmanager/IVirtualMachine.aidl
+++ b/virtmanager/aidl/android/system/virtmanager/IVirtualMachine.aidl
@@ -16,6 +16,6 @@
package android.system.virtmanager;
interface IVirtualMachine {
- /** Get the CID allocated to the VM. */
- int getCid();
+ /** Get the CID allocated to the VM. */
+ int getCid();
}
diff --git a/virtmanager/aidl/android/system/virtmanager/VirtualMachineDebugInfo.aidl b/virtmanager/aidl/android/system/virtmanager/VirtualMachineDebugInfo.aidl
new file mode 100644
index 0000000..d877a56
--- /dev/null
+++ b/virtmanager/aidl/android/system/virtmanager/VirtualMachineDebugInfo.aidl
@@ -0,0 +1,28 @@
+/*
+ * 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.
+ */
+package android.system.virtmanager;
+
+/** Information about a running VM, for debug purposes only. */
+parcelable VirtualMachineDebugInfo {
+ /** The CID assigned to the VM. */
+ int cid;
+
+ /**
+ * The filename of the config file used to start the VM. This may have changed since it was
+ * read so it shouldn't be trusted; it is only stored for debugging purposes.
+ */
+ String configPath;
+}
diff --git a/virtmanager/src/aidl.rs b/virtmanager/src/aidl.rs
index 8394e36..1b3819f 100644
--- a/virtmanager/src/aidl.rs
+++ b/virtmanager/src/aidl.rs
@@ -21,12 +21,17 @@
use android_system_virtmanager::aidl::android::system::virtmanager::IVirtualMachine::{
BnVirtualMachine, IVirtualMachine,
};
-use android_system_virtmanager::binder::{self, Interface, StatusCode, Strong};
+use android_system_virtmanager::aidl::android::system::virtmanager::VirtualMachineDebugInfo::VirtualMachineDebugInfo;
+use android_system_virtmanager::binder::{self, Interface, StatusCode, Strong, ThreadState};
use log::error;
-use std::sync::{Arc, Mutex};
+use std::sync::{Arc, Mutex, Weak};
pub const BINDER_SERVICE_IDENTIFIER: &str = "android.system.virtmanager";
+// TODO(qwandor): Use PermissionController once it is available to Rust.
+/// Only processes running with one of these UIDs are allowed to call debug methods.
+const DEBUG_ALLOWED_UIDS: [u32; 2] = [0, 2000];
+
/// Implementation of `IVirtManager`, the entry point of the AIDL service.
#[derive(Debug, Default)]
pub struct VirtManager {
@@ -42,11 +47,38 @@
fn startVm(&self, config_path: &str) -> binder::Result<Strong<dyn IVirtualMachine>> {
let state = &mut *self.state.lock().unwrap();
let cid = state.next_cid;
- let instance = start_vm(config_path, cid)?;
+ let instance = Arc::new(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(instance)))
+ state.add_vm(Arc::downgrade(&instance));
+ Ok(VirtualMachine::create(instance))
}
+
+ /// Get a list of all currently running VMs. This method is only intended for debug purposes,
+ /// and as such is only permitted from the shell user.
+ fn debugListVms(&self) -> binder::Result<Vec<VirtualMachineDebugInfo>> {
+ if !debug_access_allowed() {
+ return Err(StatusCode::PERMISSION_DENIED.into());
+ }
+
+ let state = &mut *self.state.lock().unwrap();
+ let vms = state.vms();
+ let cids = vms
+ .into_iter()
+ .map(|vm| VirtualMachineDebugInfo {
+ cid: vm.cid as i32,
+ configPath: vm.config_path.clone(),
+ })
+ .collect();
+ Ok(cids)
+ }
+}
+
+/// Check whether the caller of the current Binder method is allowed to call debug methods.
+fn debug_access_allowed() -> bool {
+ let uid = ThreadState::get_calling_uid();
+ log::trace!("Debug method call from UID {}.", uid);
+ DEBUG_ALLOWED_UIDS.contains(&uid)
}
/// Implementation of the AIDL `IVirtualMachine` interface. Used as a handle to a VM.
@@ -73,12 +105,36 @@
/// The mutable state of the Virt Manager. There should only be one instance of this struct.
#[derive(Debug)]
struct State {
+ /// The next available unused CID.
next_cid: Cid,
+
+ /// The VMs which have been started. When VMs are started a weak reference is added to this list
+ /// while a strong reference is returned to the caller over Binder. Once all copies of the
+ /// Binder client are dropped the weak reference here will become invalid, and will be removed
+ /// from the list opportunistically the next time `add_vm` is called.
+ vms: Vec<Weak<VmInstance>>,
+}
+
+impl State {
+ /// Get a list of VMs which are currently running.
+ fn vms(&self) -> Vec<Arc<VmInstance>> {
+ // Attempt to upgrade the weak pointers to strong pointers.
+ self.vms.iter().filter_map(Weak::upgrade).collect()
+ }
+
+ /// Add a new VM to the list.
+ fn add_vm(&mut self, vm: Weak<VmInstance>) {
+ // Garbage collect any entries from the stored list which no longer exist.
+ self.vms.retain(|vm| vm.strong_count() > 0);
+
+ // Actually add the new VM.
+ self.vms.push(vm);
+ }
}
impl Default for State {
fn default() -> Self {
- State { next_cid: FIRST_GUEST_CID }
+ State { next_cid: FIRST_GUEST_CID, vms: vec![] }
}
}
@@ -89,7 +145,7 @@
error!("Failed to load VM config {}: {:?}", config_path, e);
StatusCode::BAD_VALUE
})?;
- Ok(VmInstance::start(&config, cid).map_err(|e| {
+ Ok(VmInstance::start(&config, cid, config_path).map_err(|e| {
error!("Failed to start VM {}: {:?}", config_path, e);
StatusCode::UNKNOWN_ERROR
})?)
diff --git a/virtmanager/src/crosvm.rs b/virtmanager/src/crosvm.rs
index 057b791..4ae1fcd 100644
--- a/virtmanager/src/crosvm.rs
+++ b/virtmanager/src/crosvm.rs
@@ -29,19 +29,22 @@
child: Child,
/// The CID assigned to the VM for vsock communication.
pub cid: Cid,
+ /// The filename of the config file that was used to start the VM. This may have changed since
+ /// it was read so it shouldn't be trusted; it is only stored for debugging purposes.
+ pub config_path: String,
}
impl VmInstance {
/// Create a new `VmInstance` for the given process.
- fn new(child: Child, cid: Cid) -> VmInstance {
- VmInstance { child, cid }
+ fn new(child: Child, cid: Cid, config_path: &str) -> VmInstance {
+ VmInstance { child, cid, config_path: config_path.to_owned() }
}
/// Start an instance of `crosvm` to manage a new VM. The `crosvm` instance will be killed when
/// the `VmInstance` is dropped.
- pub fn start(config: &VmConfig, cid: Cid) -> Result<VmInstance, Error> {
+ pub fn start(config: &VmConfig, cid: Cid, config_path: &str) -> Result<VmInstance, Error> {
let child = run_vm(config, cid)?;
- Ok(VmInstance::new(child, cid))
+ Ok(VmInstance::new(child, cid, config_path))
}
}
diff --git a/vm/src/main.rs b/vm/src/main.rs
index 1e642cb..df375e4 100644
--- a/vm/src/main.rs
+++ b/vm/src/main.rs
@@ -35,25 +35,27 @@
if args.len() < 2 {
eprintln!("Usage:");
eprintln!(" {} run <vm_config.json>", args[0]);
+ eprintln!(" {} list", args[0]);
exit(1);
}
// We need to start the thread pool for Binder to work properly, especially link_to_death.
ProcessState::start_thread_pool();
+ let virt_manager = get_interface(VIRT_MANAGER_BINDER_SERVICE_IDENTIFIER)
+ .context("Failed to find Virt Manager service")?;
+
match args[1].as_ref() {
- "run" if args.len() == 3 => command_run(&args[2]),
+ "run" if args.len() == 3 => command_run(virt_manager, &args[2]),
+ "list" if args.len() == 2 => command_list(virt_manager),
command => bail!("Invalid command '{}' or wrong number of arguments", command),
}
}
/// Run a VM from the given configuration file.
-fn command_run(config_filename: &str) -> Result<(), Error> {
- let virt_manager: Strong<dyn IVirtManager> =
- get_interface(VIRT_MANAGER_BINDER_SERVICE_IDENTIFIER)
- .with_context(|| "Failed to find Virt Manager service")?;
- let vm = virt_manager.startVm(config_filename).with_context(|| "Failed to start VM")?;
- let cid = vm.getCid().with_context(|| "Failed to get CID")?;
+fn command_run(virt_manager: Strong<dyn IVirtManager>, config_filename: &str) -> Result<(), Error> {
+ let vm = virt_manager.startVm(config_filename).context("Failed to start VM")?;
+ let cid = vm.getCid().context("Failed to get CID")?;
println!("Started VM from {} with CID {}.", config_filename, cid);
// Wait until the VM dies. If we just returned immediately then the IVirtualMachine Binder
@@ -63,6 +65,13 @@
Ok(())
}
+/// List the VMs currently running.
+fn command_list(virt_manager: Strong<dyn IVirtManager>) -> Result<(), Error> {
+ let vms = virt_manager.debugListVms().context("Failed to get list of VMs")?;
+ println!("Running VMs: {:#?}", vms);
+ Ok(())
+}
+
/// Block until the given Binder object dies.
fn wait_for_death(binder: &mut impl IBinder) -> Result<(), Error> {
let dead = AtomicFlag::default();