kubernetes/vendor/github.com/moby/sys/userns/userns_linux.go

var inUserNS …

// runningInUserNS detects whether we are currently running in a user namespace.
//
// This code was migrated from [libcontainer/runc] and based on an implementation
// from [lcx/incus].
//
// [libcontainer/runc]: https://github.com/opencontainers/runc/blob/3778ae603c706494fd1e2c2faf83b406e38d687d/libcontainer/userns/userns_linux.go#L12-L49
// [lcx/incus]: https://github.com/lxc/incus/blob/e45085dd42f826b3c8c3228e9733c0b6f998eafe/shared/util.go#L678-L700
func runningInUserNS() bool { … }

func uidMapInUserNS(uidMap string) bool { … }