libcontainer: use Major/Minor from x/sys/unix

The Major and Minor functions were added for Linux in golang/sys@85d1495
which is already vendored in. Use these functions instead of the local
re-implementation.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

libcontainer/devices/devices_linux.go

@@ -30,8 +30,8 @@ func DeviceFromPath(path, permissions string) (*configs.Device, error) {
 	}
 
 	var (
-		devNumber = int(stat.Rdev)
-		major     = Major(devNumber)
+		devNumber = stat.Rdev
+		major     = unix.Major(devNumber)
 	)
 	if major == 0 {
 		return nil, ErrNotADevice
@@ -50,8 +50,8 @@ func DeviceFromPath(path, permissions string) (*configs.Device, error) {
 	return &configs.Device{
 		Type:        devType,
 		Path:        path,
-		Major:       major,
-		Minor:       Minor(devNumber),
+		Major:       int64(major),
+		Minor:       int64(unix.Minor(devNumber)),
 		Permissions: permissions,
 		FileMode:    os.FileMode(mode),
 		Uid:         stat.Uid,

libcontainer/devices/number.go

@@ -1,24 +0,0 @@
-// +build linux freebsd
-
-package devices
-
-/*
-
-This code provides support for manipulating linux device numbers.  It should be replaced by normal syscall functions once http://code.google.com/p/go/issues/detail?id=8106 is solved.
-
-You can read what they are here:
-
- - http://www.makelinux.net/ldd3/chp-3-sect-2
- - http://www.linux-tutorial.info/modules.php?name=MContent&pageid=94
-
-Note! These are NOT the same as the MAJOR(dev_t device);, MINOR(dev_t device); and MKDEV(int major, int minor); functions as defined in <linux/kdev_t.h> as the representation of device numbers used by go is different than the one used internally to the kernel! - https://github.com/torvalds/linux/blob/master/include/linux/kdev_t.h#L9
-
-*/
-
-func Major(devNumber int) int64 {
-	return int64((devNumber >> 8) & 0xfff)
-}
-
-func Minor(devNumber int) int64 {
-	return int64((devNumber & 0xff) | ((devNumber >> 12) & 0xfff00))
-}