agent: clean up share path created by the agent

The agent code creates a directory at
`/run/kata-containers/shared/sandboxes/sbid/` to hold shared data
between host and guest. We need to clean it up when removing a sandbox.

Fixes: #1138

Signed-off-by: Peng Tao <bergwolf@gmail.com>

virtcontainers/agent.go

@@ -254,4 +254,7 @@ type agent interface {
 
 	// copyFile copies file from host to container's rootfs
 	copyFile(src, dst string) error
+
+	// cleanup removes all on disk information generated by the agent
+	cleanup(id string)
 }

virtcontainers/hyperstart_agent.go

@@ -1012,3 +1012,10 @@ func (h *hyper) copyFile(src, dst string) error {
 	// hyperstart-agent does not support copyFile
 	return nil
 }
+
+func (h *hyper) cleanup(id string) {
+	path := h.getSharePath(id)
+	if err := os.RemoveAll(path); err != nil {
+		h.Logger().WithError(err).Errorf("failed to cleanup vm share path %s", path)
+	}
+}

virtcontainers/kata_agent.go

@@ -1835,3 +1835,11 @@ func (k *kataAgent) copyFile(src, dst string) error {
 
 	return nil
 }
+
+func (k *kataAgent) cleanup(id string) {
+	path := k.getSharePath(id)
+	k.Logger().WithField("path", path).Infof("cleanup agent")
+	if err := os.RemoveAll(path); err != nil {
+		k.Logger().WithError(err).Errorf("failed to cleanup vm share path %s", path)
+	}
+}

virtcontainers/noop_agent.go

@@ -215,3 +215,6 @@ func (n *noopAgent) setGuestDateTime(time.Time) error {
 func (n *noopAgent) copyFile(src, dst string) error {
 	return nil
 }
+
+func (n *noopAgent) cleanup(id string) {
+}

virtcontainers/sandbox.go

@@ -744,6 +744,8 @@ func (s *Sandbox) Delete() error {
 		s.Logger().WithError(err).Error("failed to cleanup hypervisor")
 	}
 
+	s.agent.cleanup(s.id)
+
 	return s.storage.deleteSandboxResources(s.id, nil)
 }