actions/image-partition: check label length in verify stage

The partition name (label) can be up to 11 characters long for vfat and 16 characters long for ext3/4.

When partition label length is longer than 11 characters for vfat, it fails with below message,
==== image-partition ====
2021/07/23 06:14:35 cmdline: [mkfs.vfat -F32 -n efi456789012 /dev/vda1]
2021/07/23 06:14:35 Formatting partition 1 | mkfs.vfat: Label can be no longer than 11 characters
2021/07/23 06:14:35 Formatting partition 1 | mkfs.fat 4.2 (2021-01-31)
2021/07/23 06:14:35 Action `image-partition` failed at stage Run, error: exit status 1

When partition label length is longer than 11 characters for ext3/4, it shows the below warning message,
2021/07/23 06:05:49 cmdline: [mkfs.ext4 -L root567890123456789 /dev/vda2]
2021/07/23 06:05:49 Formatting partition 2 | Warning: label too long; will be truncated to 'root567890123456'

This commit checks the label length for all partition types in verify action and exits if it is longer than
the above values.

Signed-off-by: Vignesh Raman <[email protected]>

actions/image_partition_action.go

@@ -668,7 +668,20 @@ func (i *ImagePartitionAction) Verify(context *debos.DebosContext) error {
 
 		for pidx, _ := range i.Partitions {
 			p := &i.Partitions[pidx]
+			var partNameLen int
+
 			if m.Partition == p.Name {
+				switch p.FS {
+				case "vfat":
+					partNameLen = 11
+				case "ext3", "ext4":
+					partNameLen = 16
+				}
+
+				if len(p.Name) > partNameLen {
+					return fmt.Errorf("incorrect partition name '%s', should be less than %d characters for '%s'", p.Name, partNameLen, p.FS)
+				}
+
 				m.part = p
 				break
 			}