From 16908e1ec833d857cb418712c382c6f604426b36 Mon Sep 17 00:00:00 2001
From: Frantisek Sumsal <frantisek@sumsal.cz>
Date: Tue, 1 Feb 2022 20:18:29 +0100
Subject: [PATCH] test: introduce `get_cgroup_hierarchy() helper

which returns the host's cgroup hierarchy (unified, hybrid, or legacy).

(cherry picked from commit f723740871bd3eb89d16a526a1ff77c04bb3787a)

Related: #2047768
---
 test/test-functions | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/test-functions b/test/test-functions
index 35d8f074a9..4827b6bedf 100644
--- a/test/test-functions
+++ b/test/test-functions
@@ -1996,6 +1996,24 @@ import_initdir() {
     export initdir
 }
 
+get_cgroup_hierarchy() {
+    case "$(stat -c '%T' -f /sys/fs/cgroup)" in
+        cgroup2fs)
+            echo "unified"
+            ;;
+        tmpfs)
+            if [[ -d /sys/fs/cgroup/unified && "$(stat -c '%T' -f /sys/fs/cgroup/unified)" == cgroup2fs ]]; then
+                echo "hybrid"
+            else
+                echo "legacy"
+            fi
+            ;;
+        *)
+            dfatal "Failed to determine host's cgroup hierarchy"
+            exit 1
+    esac
+}
+
 ## @brief Converts numeric logging level to the first letter of level name.
 #
 # @param lvl Numeric logging level in range from 1 to 6.