daemon, o/i/apparmorprompting: simplify ShutDown

Author: natibek

daemon/api_prompting_test.go

@@ -58,7 +58,6 @@ type fakeInterfacesRequestsManager struct {
 	iface                string
 	pid                  int32
 	cgroup               string
-	snapdShuttingDown    <-chan struct{}
 	id                   prompting.IDType // used for prompt ID or rule ID
 	ruleConstraintsJSON  prompting.ConstraintsJSON
 	constraintsPatchJSON prompting.ConstraintsJSON
@@ -732,7 +731,6 @@ func (s *promptingSuite) TestPostInterfacesRequestsHappy(c *C) {
 	c.Check(s.manager.snap, Equals, expectedSnap)
 	c.Check(s.manager.pid, Equals, fakePID)
 	c.Check(s.manager.cgroup, Equals, fakeCgroup)
-	c.Check(s.manager.snapdShuttingDown, NotNil)
 
 	// Check return value
 	responseBody, ok := rsp.Result.(daemon.PostInterfacesRequestsResponse)

overlord/ifacestate/apparmorprompting/prompting.go

@@ -85,8 +85,12 @@ type InterfacesRequestsManager struct {
 	// listener readiness.
 	listenerAlreadySignalled chan struct{}
 
+	// snapdShuttingDown is closed when overlord.ShutDown is called to
+	// signal that the daemon is going to be stopped and the
+	// InterfacesRequestsManager needs to stop receiving requests and
+	// finish handling existing requests.
 	snapdShuttingDown chan struct{}
-	shuttingDownOnce  sync.Once
+	shutdown          bool
 
 	askRequests chan *prompting.Request
 }
@@ -390,9 +394,11 @@ func (m *InterfacesRequestsManager) Ask(uid uint32, iface, snap string, pid int3
 // ShutDown stops the listener, prompt DB, and rule DB from receiving new
 // requests.
 func (m *InterfacesRequestsManager) ShutDown() {
-	m.shuttingDownOnce.Do(func() {
-		close(m.snapdShuttingDown)
-	})
+	if m.shutdown {
+		return
+	}
+	close(m.snapdShuttingDown)
+	m.shutdown = true
 }
 
 // Stop closes the listener, prompt DB, and rule DB. Stop is idempotent, and