commit 7e54e2904f414369054114a0d5b9ed0e6d3a23cd
author Alan Stokes <alanstokes@google.com> Thu Sep 09 11:37:56 2021 +0100
committer Alan Stokes <alanstokes@google.com> Fri Sep 10 11:40:53 2021 +0100
tree 528e83002ac8e644fd00b47372fb0a77471ab657
parent f8d941138dc0da9a1bf4a1de0e3ef9b626cd8898

Register as a lazy service.

This allows the service manager to shut down the virtualization
service process when the service is no longer in use.

Also ensure that our process is not killed while we are holding debug
VM refs; this ensures "vm run --daemonize" works as expected.

Bug: 199367367
Test: Run compos_key_cmd to start a VM and exit; VS process is stopped.
Test: atest ComposKeyTestCase; passes, VS exits at end
Change-Id: Iffbaf715bbd64d0e85d0ca544e6a95b100cdd3df

virtualizationservice/src/aidl.rs

diff --git a/virtualizationservice/src/aidl.rs b/virtualizationservice/src/aidl.rs
index 2c1011b..78a70d7 100644
--- a/virtualizationservice/src/aidl.rs
+++ b/virtualizationservice/src/aidl.rs
@@ -35,7 +35,7 @@
     VirtualMachineState::VirtualMachineState,
 };
 use android_system_virtualizationservice::binder::{
-    self, BinderFeatures, ExceptionCode, Interface, ParcelFileDescriptor, Status, Strong, ThreadState,
+    self, force_lazy_services_persist, BinderFeatures, ExceptionCode, Interface, ParcelFileDescriptor, Status, Strong, ThreadState,
 };
 use android_system_virtualmachineservice::aidl::android::system::virtualmachineservice::IVirtualMachineService::{
     VM_BINDER_SERVICE_PORT, VM_STREAM_SERVICE_PORT, BnVirtualMachineService, IVirtualMachineService,
@@ -716,12 +716,20 @@
     /// Store a strong VM reference.
     fn debug_hold_vm(&mut self, vm: Strong<dyn IVirtualMachine>) {
         self.debug_held_vms.push(vm);
+        // Make sure our process is not shut down while we hold the VM reference
+        // on behalf of the caller.
+        force_lazy_services_persist(true);
     }
 
     /// Retrieve and remove a strong VM reference.
     fn debug_drop_vm(&mut self, cid: i32) -> Option<Strong<dyn IVirtualMachine>> {
         let pos = self.debug_held_vms.iter().position(|vm| vm.getCid() == Ok(cid))?;
-        Some(self.debug_held_vms.swap_remove(pos))
+        let vm = self.debug_held_vms.swap_remove(pos);
+        if self.debug_held_vms.is_empty() {
+            // Once we no longer hold any VM references it is ok for our process to be shut down.
+            force_lazy_services_persist(false);
+        }
+        Some(vm)
     }
 
     /// Get the next available CID, or an error if we have run out.

virtualizationservice/src/main.rs

diff --git a/virtualizationservice/src/main.rs b/virtualizationservice/src/main.rs
index 8628c01..22ddf08 100644
--- a/virtualizationservice/src/main.rs
+++ b/virtualizationservice/src/main.rs
@@ -21,7 +21,7 @@
 
 use crate::aidl::{VirtualizationService, BINDER_SERVICE_IDENTIFIER, TEMPORARY_DIRECTORY};
 use android_system_virtualizationservice::aidl::android::system::virtualizationservice::IVirtualizationService::BnVirtualizationService;
-use android_system_virtualizationservice::binder::{add_service, BinderFeatures, ProcessState};
+use android_system_virtualizationservice::binder::{register_lazy_service, BinderFeatures, ProcessState};
 use anyhow::Error;
 use log::{info, Level};
 use std::fs::{remove_dir_all, remove_file, read_dir};
@@ -47,7 +47,7 @@
         service,
         BinderFeatures { set_requesting_sid: true, ..BinderFeatures::default() },
     );
-    add_service(BINDER_SERVICE_IDENTIFIER, service.as_binder()).unwrap();
+    register_lazy_service(BINDER_SERVICE_IDENTIFIER, service.as_binder()).unwrap();
     info!("Registered Binder service, joining threadpool.");
     ProcessState::join_thread_pool();
 }