Fix VMM shutdown handler to always terminate shim process

When handleVMMShutdown is called and the VM is already stopped (CanStop()
returns false), the handler previously did nothing to terminate the shim
process, leaving it orphaned. Now we always call the context cancel function
after attempting vm.Stop(), ensuring the process exits through the existing
graceful shutdown flow regardless of VM state.

Author: cursoragent

cmd/vz-shim/main.go

@@ -61,7 +61,7 @@ func main() {
 	slog.Info("VM started", "vcpus", config.VCPUs, "memory_mb", config.MemoryBytes/1024/1024)
 
 	// Create the shim server
-	server := NewShimServer(vm, vmConfig)
+	server := NewShimServer(vm, vmConfig, cancel)
 
 	// Start control socket listener (remove stale socket from previous run)
 	os.Remove(config.ControlSocket)

cmd/vz-shim/server.go

@@ -4,6 +4,7 @@ package main
 
 import (
 	"bufio"
+	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -19,14 +20,16 @@ import (
 type ShimServer struct {
 	vm       *vz.VirtualMachine
 	vmConfig *vz.VirtualMachineConfiguration
+	cancel   context.CancelFunc
 	mu       sync.RWMutex
 }
 
 // NewShimServer creates a new shim server.
-func NewShimServer(vm *vz.VirtualMachine, vmConfig *vz.VirtualMachineConfiguration) *ShimServer {
+func NewShimServer(vm *vz.VirtualMachine, vmConfig *vz.VirtualMachineConfiguration, cancel context.CancelFunc) *ShimServer {
 	return &ShimServer{
 		vm:       vm,
 		vmConfig: vmConfig,
+		cancel:   cancel,
 	}
 }
 
@@ -151,7 +154,9 @@ func (s *ShimServer) handleVMMShutdown(w http.ResponseWriter, r *http.Request) {
 		if s.vm.CanStop() {
 			s.vm.Stop()
 		}
-		// Process will exit when VM stops (monitored in main)
+		// Ensure process terminates even if VM is already stopped
+		// (e.g. CanStop() returned false because the VM already stopped).
+		s.cancel()
 	}()
 }