Refactor and improve libcontainer and driver

Remove logging for now because it is complicating things
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

libcontainer/utils/utils.go

@@ -4,6 +4,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"io"
+	"path/filepath"
 )
 
 // GenerateRandomName returns a new name joined with a prefix.  This size
@@ -15,3 +16,13 @@ func GenerateRandomName(prefix string, size int) (string, error) {
 	}
 	return prefix + hex.EncodeToString(id)[:size], nil
 }
+
+// ResolveRootfs ensures that the current working directory is
+// not a symlink and returns the absolute path to the rootfs
+func ResolveRootfs(uncleanRootfs string) (string, error) {
+	rootfs, err := filepath.Abs(uncleanRootfs)
+	if err != nil {
+		return "", err
+	}
+	return filepath.EvalSymlinks(rootfs)
+}