devices: filter /dev/console out of the node list

Fixed getDeviceNodes() so it won't add /dev/console to the device node
list.

This fixes an issue where containers wouldn't start if
/dev/console is a pts (which is the case when running docker inside
docker), because devpts inodes are special and cannot be created with
mknod: attempting to open the result of doing so will return EIO.

Since later libcontainer would attempt to open the file to mount --bind
over it and fail because of the EIO error, the container wouldn't start
if the /dev/console was a pts, which is the case inside a docker
that was started from a pts.

getDeviceNodes() already filters pts so this change is consistent
with the current behavior.

Signed-off-by: Alejandro Ojeda <alex@x3y.org>

devices/devices.go

@@ -115,14 +115,19 @@ func getDeviceNodes(path string) ([]*Device, error) {
 			}
 		}
 
-		device, err := GetDevice(filepath.Join(path, f.Name()), "rwm")
+		switch f.Name() {
-		if err != nil {
+		case "console":
-			if err == ErrNotADeviceNode {
+			continue
-				continue
+		default:
+			device, err := GetDevice(filepath.Join(path, f.Name()), "rwm")
+			if err != nil {
+				if err == ErrNotADeviceNode {
+					continue
+				}
+				return nil, err
 			}
-			return nil, err
+			out = append(out, device)
 		}
-		out = append(out, device)
 	}
 
 	return out, nil