commit a4e2a4a6589e34e3c79218ef425de4030ce9c3eb
author Alan Stokes <alanstokes@google.com> Mon Nov 28 12:04:39 2022 +0000
committer Alan Stokes <alanstokes@google.com> Mon Nov 28 13:45:50 2022 +0000
tree 2ca8a65997207e5697e9de5b6bf18880f02c18f0
parent 03a8770262e22f9a333cc1b8349d08c260e33b08

Close() shouldn't throw

Close() should handle releasing resources when we are no longer using
a VM (since we implement autoCloseable). It shouldn't throw if th VM
is stopped - that just means nothing is being used.

We could get rid of stop(), or give it the same semantics, but I think
it has uses - if the app should be running then stop() throwing shows
something is wrong.

Add tests. Also minor gratuitous simplification in benchmark code.

Bug: 258397314
Test: atest MicrodroidTests
Change-Id: Ia8a6661ba1664368ba7f09ed0e4dcb8b39469fb8

javalib/api/system-current.txt

diff --git a/javalib/api/system-current.txt b/javalib/api/system-current.txt
index 850bffc..16995c5 100644
--- a/javalib/api/system-current.txt
+++ b/javalib/api/system-current.txt
@@ -3,7 +3,7 @@
 
   public class VirtualMachine implements java.lang.AutoCloseable {
     method public void clearCallback();
-    method public void close() throws android.system.virtualmachine.VirtualMachineException;
+    method public void close();
     method @NonNull public android.os.IBinder connectToVsockServer(int) throws android.system.virtualmachine.VirtualMachineException;
     method @NonNull public android.os.ParcelFileDescriptor connectVsock(int) throws android.system.virtualmachine.VirtualMachineException;
     method public int getCid() throws android.system.virtualmachine.VirtualMachineException;

javalib/src/android/system/virtualmachine/VirtualMachine.java

diff --git a/javalib/src/android/system/virtualmachine/VirtualMachine.java b/javalib/src/android/system/virtualmachine/VirtualMachine.java
index 193d213..dec873f 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachine.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachine.java
@@ -65,6 +65,7 @@
 import android.system.virtualizationservice.VirtualMachineAppConfig;
 import android.system.virtualizationservice.VirtualMachineState;
 import android.util.JsonReader;
+import android.util.Log;
 
 import com.android.internal.annotations.GuardedBy;
 
@@ -105,6 +106,8 @@
  */
 @SystemApi
 public class VirtualMachine implements AutoCloseable {
+    private static final String TAG = "VirtualMachine";
+
     /** Name of the directory under the files directory where all VMs created for the app exist. */
     private static final String VM_DIR = "vm";
 
@@ -754,7 +757,8 @@
      * computer; the machine halts immediately. Software running on the virtual machine is not
      * notified of the event. A stopped virtual machine can be re-started by calling {@link #run()}.
      *
-     * @throws VirtualMachineException if the virtual machine could not be stopped.
+     * @throws VirtualMachineException if the virtual machine is not running or could not be
+     *     stopped.
      * @hide
      */
     @SystemApi
@@ -775,15 +779,31 @@
     }
 
     /**
-     * Stops this virtual machine. See {@link #stop()}.
+     * Stops this virtual machine, if it is running.
      *
-     * @throws VirtualMachineException if the virtual machine could not be stopped.
+     * @see #stop()
      * @hide
      */
     @SystemApi
     @Override
-    public void close() throws VirtualMachineException {
-        stop();
+    public void close() {
+        synchronized (mLock) {
+            if (mVirtualMachine == null) {
+                return;
+            }
+            try {
+                if (stateToStatus(mVirtualMachine.getState()) == STATUS_RUNNING) {
+                    mVirtualMachine.stop();
+                    mVirtualMachine = null;
+                }
+            } catch (RemoteException e) {
+                throw e.rethrowAsRuntimeException();
+            } catch (ServiceSpecificException e) {
+                // Deliberately ignored; this almost certainly means the VM exited just as
+                // we tried to stop it.
+                Log.i(TAG, "Ignoring error on close()", e);
+            }
+        }
     }
 
     private static void deleteRecursively(File dir) throws IOException {