From aa8003ca79589e6ab8a1d081b2d768eb9f35b5c8 Mon Sep 17 00:00:00 2001
From: Cameron Sparr <sparrc@users.noreply.github.com>
Date: Wed, 16 Feb 2022 17:48:07 -0800
Subject: [PATCH] Fix systemd full path

Signed-off-by: Cameron Sparr <sparrc@users.noreply.github.com>
---
 v2/manager.go      | 33 ++++++++++++++++++++---
 v2/manager_test.go | 65 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+), 3 deletions(-)

diff --git a/v2/manager.go b/v2/manager.go
index f5466785..c08d9a7d 100644
--- a/v2/manager.go
+++ b/v2/manager.go
@@ -701,12 +701,39 @@ func setDevices(path string, devices []specs.LinuxDeviceCgroup) error {
 	return nil
 }
 
+// getSystemdFullPath returns the full systemd path when creating a systemd slice group.
+// the reason this is necessary is because the "-" character has a special meaning in
+// systemd slice. For example, when creating a slice called "my-group-112233.slice",
+// systemd will create a hierarchy like this:
+//      /sys/fs/cgroup/my.slice/my-group.slice/my-group-112233.slice
+func getSystemdFullPath(slice, group string) string {
+	return filepath.Join(defaultCgroup2Path, dashesToPath(slice), dashesToPath(group))
+}
+
+// dashesToPath converts a slice name with dashes to it's corresponding systemd filesystem path.
+func dashesToPath(in string) string {
+	path := ""
+	if strings.HasSuffix(in, ".slice") && strings.Contains(in, "-") {
+		parts := strings.Split(in, "-")
+		for i := range parts {
+			s := strings.Join(parts[0:i+1], "-")
+			if !strings.HasSuffix(s, ".slice") {
+				s += ".slice"
+			}
+			path = filepath.Join(path, s)
+		}
+	} else {
+		path = filepath.Join(path, in)
+	}
+	return path
+}
+
 func NewSystemd(slice, group string, pid int, resources *Resources) (*Manager, error) {
 	if slice == "" {
 		slice = defaultSlice
 	}
 	ctx := context.TODO()
-	path := filepath.Join(defaultCgroup2Path, slice, group)
+	path := getSystemdFullPath(slice, group)
 	conn, err := systemdDbus.NewWithContext(ctx)
 	if err != nil {
 		return &Manager{}, err
@@ -796,9 +823,9 @@ func LoadSystemd(slice, group string) (*Manager, error) {
 	if slice == "" {
 		slice = defaultSlice
 	}
-	group = filepath.Join(defaultCgroup2Path, slice, group)
+	path := getSystemdFullPath(slice, group)
 	return &Manager{
-		path: group,
+		path: path,
 	}, nil
 }
 
diff --git a/v2/manager_test.go b/v2/manager_test.go
index 35d104ca..650af280 100644
--- a/v2/manager_test.go
+++ b/v2/manager_test.go
@@ -22,6 +22,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"go.uber.org/goleak"
 )
 
@@ -74,3 +75,67 @@ func TestEventChanCleanupOnCgroupRemoval(t *testing.T) {
 	}
 	goleak.VerifyNone(t)
 }
+
+func TestSystemdFullPath(t *testing.T) {
+	tests := []struct {
+		inputSlice  string
+		inputGroup  string
+		expectedOut string
+	}{
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "myGroup.slice",
+			expectedOut: "/sys/fs/cgroup/user.slice/myGroup.slice",
+		},
+		{
+			inputSlice:  "/",
+			inputGroup:  "myGroup.slice",
+			expectedOut: "/sys/fs/cgroup/myGroup.slice",
+		},
+		{
+			inputSlice:  "system.slice",
+			inputGroup:  "myGroup.slice",
+			expectedOut: "/sys/fs/cgroup/system.slice/myGroup.slice",
+		},
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "my-group.slice",
+			expectedOut: "/sys/fs/cgroup/user.slice/my.slice/my-group.slice",
+		},
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "my-group-more-dashes.slice",
+			expectedOut: "/sys/fs/cgroup/user.slice/my.slice/my-group.slice/my-group-more.slice/my-group-more-dashes.slice",
+		},
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "my-group-dashes.slice",
+			expectedOut: "/sys/fs/cgroup/user.slice/my.slice/my-group.slice/my-group-dashes.slice",
+		},
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "myGroup.scope",
+			expectedOut: "/sys/fs/cgroup/user.slice/myGroup.scope",
+		},
+		{
+			inputSlice:  "user.slice",
+			inputGroup:  "my-group-dashes.scope",
+			expectedOut: "/sys/fs/cgroup/user.slice/my-group-dashes.scope",
+		},
+		{
+			inputSlice:  "test-waldo.slice",
+			inputGroup:  "my-group.slice",
+			expectedOut: "/sys/fs/cgroup/test.slice/test-waldo.slice/my.slice/my-group.slice",
+		},
+		{
+			inputSlice:  "test-waldo.slice",
+			inputGroup:  "my.service",
+			expectedOut: "/sys/fs/cgroup/test.slice/test-waldo.slice/my.service",
+		},
+	}
+
+	for _, test := range tests {
+		actual := getSystemdFullPath(test.inputSlice, test.inputGroup)
+		assert.Equal(t, test.expectedOut, actual)
+	}
+}