userns: add new option --userns=keep-id

it creates a namespace where the current UID:GID on the host is mapped
to the same UID:GID in the container.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/pkg/namespaces/namespaces.go b/pkg/namespaces/namespaces.go
index fde6118af..ec9276344 100644
--- a/pkg/namespaces/namespaces.go
+++ b/pkg/namespaces/namespaces.go
@@ -12,6 +12,11 @@ func (n UsernsMode) IsHost() bool {
 	return n == "host"
 }
 
+// IsKeepID indicates whether container uses a mapping where the (uid, gid) on the host is lept inside of the namespace.
+func (n UsernsMode) IsKeepID() bool {
+	return n == "keep-id"
+}
+
 // IsPrivate indicates whether the container uses the a private userns.
 func (n UsernsMode) IsPrivate() bool {
 	return !(n.IsHost())
@@ -21,7 +26,7 @@ func (n UsernsMode) IsPrivate() bool {
 func (n UsernsMode) Valid() bool {
 	parts := strings.Split(string(n), ":")
 	switch mode := parts[0]; mode {
-	case "", "host":
+	case "", "host", "keep-id":
 	default:
 		return false
 	}