Implemented a new shutdownCh on the VM struct, which allows closure from the Shutdown receiver to trigger startVMM to continue when using daemonized jailer process.

Signed-off-by: Adam Thomason <adam.thomason@a17n.co.uk>

Author: adamthomason

machine.go

@@ -268,6 +268,8 @@ type Machine struct {
 	startOnce sync.Once
 	// exitCh is a channel which gets closed when the VMM exits
 	exitCh chan struct{}
+	// shutdownCh is a channel which gets closed when the VM is shutdown
+	shutdownCh chan struct{}
 	// fatalErr records an error that either stops or prevent starting the VMM
 	fatalErr error
 
@@ -360,8 +362,9 @@ func configureBuilder(builder VMCommandBuilder, cfg Config) VMCommandBuilder {
 // provided Config.
 func NewMachine(ctx context.Context, cfg Config, opts ...Opt) (*Machine, error) {
 	m := &Machine{
-		exitCh:    make(chan struct{}),
-		cleanupCh: make(chan struct{}),
+		exitCh:     make(chan struct{}),
+		shutdownCh: make(chan struct{}),
+		cleanupCh:  make(chan struct{}),
 	}
 
 	if cfg.VMID == "" {
@@ -460,6 +463,9 @@ func (m *Machine) Start(ctx context.Context) error {
 // Shutdown requests a clean shutdown of the VM by sending CtrlAltDelete on the virtual keyboard
 func (m *Machine) Shutdown(ctx context.Context) error {
 	m.logger.Debug("Called machine.Shutdown()")
+
+	close(m.shutdownCh)
+
 	if runtime.GOARCH != "arm64" {
 		return m.sendCtrlAltDel(ctx)
 	} else {
@@ -591,11 +597,10 @@ func (m *Machine) startVMM(ctx context.Context) error {
 
 		// If using daemonized jailer and parent exits cleanly,
 		// this is expected behavior. Don't treat it as an error.
-		// We return immediately and allow subsequent functions
-		// (such as waitForSocket) to send any errors to channels.
+		// We instead wait for closure of shutdownCh from m.Shutdown().
 		if m.Cfg.JailerCfg != nil && m.Cfg.JailerCfg.Daemonize && waitErr == nil {
 			m.logger.Debugf("jailer parent exited (expected for daemonized mode)")
-			return
+			<-m.shutdownCh
 		}
 
 		if waitErr != nil {