mount: Virtio-blk container rootfs mount for ACRN hypervisor

For block devices added by acrn, virtpath is directly udpated
in storage.source and so no scanning of PCIAddr is required.
This is because, the virtio-blk device is not hot-plugged but
added during VM launch and updated later with container rootfs
using block rescan feature.

v2->v3:
1. Addressed weak match for checking storage block device.
2. Added device check for storage block device.
3. Added negative unit tests for the new code.

v1->v2:
gofmt'd the mount file.

Fixes: kata-containers#573

Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>

mount.go

@@ -271,13 +271,28 @@ func virtioFSStorageHandler(storage pb.Storage, s *sandbox) (string, error) {
 
 // virtioBlkStorageHandler handles the storage for blk driver.
 func virtioBlkStorageHandler(storage pb.Storage, s *sandbox) (string, error) {
-	// Get the device node path based on the PCI address provided
-	// in Storage Source
-	devPath, err := getPCIDeviceName(s, storage.Source)
-	if err != nil {
-		return "", err
+
+	// If hot-plugged, get the device node path based on the PCI address else
+	// use the virt path provided in Storage Source
+	if strings.HasPrefix(storage.Source, "/dev") {
+
+		FileInfo, err := os.Stat(storage.Source)
+		if err != nil {
+			return "", err
+		}
+		// Make sure the virt path is valid
+		if FileInfo.Mode()&os.ModeDevice == 0 {
+			return "", err
+		}
+
+	} else {
+		devPath, err := getPCIDeviceName(s, storage.Source)
+		if err != nil {
+			return "", err
+		}
+
+		storage.Source = devPath
 	}
-	storage.Source = devPath
 
 	return commonStorageHandler(storage)
 }

mount_test.go

@@ -125,6 +125,30 @@ func TestVirtio9pStorageHandlerSuccessful(t *testing.T) {
 	assert.Nil(t, err, "storage9pDriverHandler() failed: %v", err)
 }
 
+func TestVirtioBlkStoragePathFailure(t *testing.T) {
+	s := &sandbox{}
+
+	storage := pb.Storage{
+		Source: "/home/developer/test",
+	}
+
+	_, err := virtioBlkStorageHandler(storage, s)
+	agentLog.WithError(err).Error("virtioBlkStorageHandler error")
+	assert.NotNil(t, err, "virtioBlkStorageHandler() should have failed")
+}
+
+func TestVirtioBlkStorageDeviceFailure(t *testing.T) {
+	s := &sandbox{}
+
+	storage := pb.Storage{
+		Source: "/dev/foo",
+	}
+
+	_, err := virtioBlkStorageHandler(storage, s)
+	agentLog.WithError(err).Error("virtioBlkStorageHandler error")
+	assert.NotNil(t, err, "virtioBlkStorageHandler() should have failed")
+}
+
 func TestVirtioBlkStorageHandlerSuccessful(t *testing.T) {
 	skipUnlessRoot(t)