Add `vm` tool for talking to Virt Manager.
For now it just has a single command, to run a specified VM.
Bug: 181869875
Test: Started a VM on a VIM3L
Change-Id: Ifdaaccb3be92e774ee4d7672914a3014220af489
diff --git a/vm/src/sync.rs b/vm/src/sync.rs
new file mode 100644
index 0000000..82839b3
--- /dev/null
+++ b/vm/src/sync.rs
@@ -0,0 +1,46 @@
+// 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.
+
+//! Synchronisation utilities.
+
+use std::sync::{Arc, Condvar, Mutex};
+
+/// A flag which one thread can use to notify other threads when a condition becomes true. This is
+/// something like a single-use binary semaphore.
+#[derive(Clone, Debug)]
+pub struct AtomicFlag {
+ state: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl Default for AtomicFlag {
+ #[allow(clippy::mutex_atomic)]
+ fn default() -> Self {
+ Self { state: Arc::new((Mutex::new(false), Condvar::new())) }
+ }
+}
+
+#[allow(clippy::mutex_atomic)]
+impl AtomicFlag {
+ /// Wait until the flag is set.
+ pub fn wait(&self) {
+ let _flag = self.state.1.wait_while(self.state.0.lock().unwrap(), |flag| !*flag).unwrap();
+ }
+
+ /// Set the flag, and notify all waiting threads.
+ pub fn raise(&self) {
+ let mut flag = self.state.0.lock().unwrap();
+ *flag = true;
+ self.state.1.notify_all();
+ }
+}