*: abstract out netns for multiple platforms

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

lib/sandbox/sandbox_unsupported.go

@@ -0,0 +1,49 @@
+// +build !linux
+
+package sandbox
+
+import (
+	"os"
+)
+
+func isNSorErr(nspath string) error {
+	return nil // TODO(vbatts) ... really not sure ...
+}
+
+func newNetNs() (*NetNs, error) {
+	return &NetNs{}, nil
+}
+
+func getNetNs(path string) (*NetNs, error) {
+	return &NetNs{}, nil
+}
+
+// NetNs handles data pertaining a network namespace
+// for non-linux this is a noop
+type NetNs struct {
+	symlink *os.File
+}
+
+func (nns *NetNs) Path() string {
+	return ""
+}
+
+func (nns *NetNs) symlinkCreate(name string) error {
+	return nil
+}
+
+func (nns *NetNs) symlinkRemove() error {
+	return nil
+}
+
+func (nns *NetNs) Close() error {
+	return nil
+}
+
+func (nns *NetNs) Remove() error {
+	return nil
+}
+
+func hostNetNsPath() (string, error) {
+	return "", nil // TODO(vbatts) maybe this should have a platform error?
+}