rootless: detect user namespace configuration changes

detect if the current user namespace doesn't match the configuration
in the /etc/subuid and /etc/subgid files.

If there is a mismatch, raise a warning and suggest the user to
recreate the user namespace with "system migrate", that also restarts
the containers.

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

1 files changed, 6 insertions, 0 deletions

diff --git a/pkg/rootless/rootless_unsupported.go b/pkg/rootless/rootless_unsupported.go
index a8485c083..16ba228e2 100644
--- a/pkg/rootless/rootless_unsupported.go
+++ b/pkg/rootless/rootless_unsupported.go
@@ -53,3 +53,9 @@ func EnableLinger() (string, error) {
 func TryJoinFromFilePaths(pausePidPath string, needNewNamespace bool, paths []string) (bool, int, error) {
 	return false, -1, errors.New("this function is not supported on this os")
 }
+
+// ConfigurationMatches checks whether the additional uids/gids configured for the user
+// match the current user namespace.
+func ConfigurationMatches() (bool, error) {
+	return true, nil
+}