Try to handle cgroups v2 unified hierarchy

By simply fixing the cgroup path.

main.go

@@ -309,8 +309,7 @@ func getCgroupsForPid(pid int) (map[string]string, error) {
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		line := strings.SplitN(scanner.Text(), ":", 3)
-		// line[1] == "" excludes the cgroupv2 unified hierarchy entry.
-		if len(line) != 3 || line[1] == "" {
+		if len(line) != 3 {
 			continue
 		}
 
@@ -325,6 +324,9 @@ func getCgroupsForPid(pid int) (map[string]string, error) {
 }
 
 func constructCgroupPath(cgroupName string, cgroupPath string) string {
+	if cgroupName == "" {
+		cgroupName = "unified"
+	}
 	return path.Join(SYSFS, strings.TrimPrefix(cgroupName, "name="), cgroupPath, PROCS)
 }