DetectUID detects UID from the OwnerUID field of `busctl --user status` if running in userNS.

DetectUserDbusSessionBusAddress returns $DBUS_SESSION_BUS_ADDRESS, if set.

systemd represents slice hierarchy using `-`, so we need to follow suit when generating the path of slice.

NOTE: This function comes from package github.com/coreos/go-systemd/util It was borrowed here to avoid a dependency on cgo.

RangeToBits converts a text representation of a CPU mask (as written to or read from cgroups' cpuset.* files, e.g.

GenerateDeviceProps is a function to generate systemd device properties, used by Set methods.