1 files changed, 15 insertions, 0 deletions
diff --git a/pkg/rootless/rootless.go b/pkg/rootless/rootless.go
index d02721ea9..3c33597b6 100644
--- a/pkg/rootless/rootless.go
+++ b/pkg/rootless/rootless.go
@@ -4,6 +4,7 @@ import (
 	"os"
 
 	"github.com/containers/storage"
+	"github.com/opencontainers/runc/libcontainer/user"
 	"github.com/pkg/errors"
 )
 
@@ -46,3 +47,17 @@ func TryJoinPauseProcess(pausePidPath string) (bool, int, error) {
 	}
 	return became, ret, err
 }
+
+// GetAvailableGids returns how many GIDs are available in the
+// current user namespace.
+func GetAvailableGids() (int64, error) {
+	idMap, err := user.ParseIDMapFile("/proc/self/gid_map")
+	if err != nil {
+		return 0, err
+	}
+	count := int64(0)
+	for _, r := range idMap {
+		count += r.Count
+	}
+	return count, nil
+}