From 2f9052ca29d0e148554088c72c40c95d3236fe04 Mon Sep 17 00:00:00 2001
From: Alexander Morozov <lk4d4@docker.com>
Date: Mon, 10 Aug 2015 12:19:20 -0700
Subject: [PATCH] Fix cgroup parent searching

I had pretty convenient input data to miss this bug.

Signed-off-by: Alexander Morozov <lk4d4@docker.com>
---
 libcontainer/cgroups/fs/apply_raw.go      |  2 +-
 libcontainer/cgroups/fs/apply_raw_test.go | 29 +++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 libcontainer/cgroups/fs/apply_raw_test.go

diff --git a/libcontainer/cgroups/fs/apply_raw.go b/libcontainer/cgroups/fs/apply_raw.go
index f75dab1b..cd6c0a88 100644
--- a/libcontainer/cgroups/fs/apply_raw.go
+++ b/libcontainer/cgroups/fs/apply_raw.go
@@ -240,7 +240,7 @@ func (raw *data) parent(subsystem, mountpoint, src string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-	relDir, err := filepath.Rel(src, initPath)
+	relDir, err := filepath.Rel(initPath, src)
 	if err != nil {
 		return "", err
 	}
diff --git a/libcontainer/cgroups/fs/apply_raw_test.go b/libcontainer/cgroups/fs/apply_raw_test.go
new file mode 100644
index 00000000..50aff591
--- /dev/null
+++ b/libcontainer/cgroups/fs/apply_raw_test.go
@@ -0,0 +1,29 @@
+package fs
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+)
+
+func TestCgroupParent(t *testing.T) {
+	raw := &data{
+		cgroup: "",
+	}
+	subsystem := "memory"
+	subPath := "/docker/874e38c82a6c630dc95f3f1f2c8d8f43efb531d35a9f46154ab2fde1531b7bb6"
+	initPath, err := cgroups.GetInitCgroupDir(subsystem)
+	if err != nil {
+		t.Fatal(err)
+	}
+	srcPath := filepath.Join(initPath, subPath)
+	cgPath := "/sys/fs/cgroup/memory"
+	path, err := raw.parent(subsystem, cgPath, srcPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if path != filepath.Join(cgPath, subPath) {
+		t.Fatalf("Unexpected path: %s, should be %s", path, filepath.Join(cgPath, subPath))
+	}
+}