From 5fb0f19ec8c52ed0c9bbb3551deb0016992ecc52 Mon Sep 17 00:00:00 2001

From: Giuseppe Scrivano <gscrivan@redhat.com>

Date: Thu, 3 Oct 2019 15:58:39 +0200

Subject: [PATCH] cgroups: raise an error on cgroups v2

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

---

 create.go      |  8 ++++++++

 run.go         |  8 ++++++++

 utils_linux.go | 14 ++++++++++++++

 3 files changed, 30 insertions(+)

diff --git a/create.go b/create.go

index 5f3ac609..91d17d07 100644

--- a/create.go

+++ b/create.go

@@ -1,6 +1,7 @@

 package main

 import (

+	"fmt"

 	"os"

 	"github.com/urfave/cli"

@@ -52,6 +53,13 @@ command(s) that get executed on start, edit the args parameter of the spec. See

 		},

 	},

 	Action: func(context *cli.Context) error {

+		unified, err := IsCgroup2UnifiedMode()

+		if  err != nil {

+			return err

+		}

+		if unified {

+			return fmt.Errorf("this version of runc doesn't work on cgroups v2")

+		}

 		if err := checkArgs(context, 1, exactArgs); err != nil {

 			return err

 		}

diff --git a/run.go b/run.go

index f8d63178..3f29737b 100644

--- a/run.go

+++ b/run.go

@@ -3,6 +3,7 @@

 package main

 import (

+	"fmt"

 	"os"

 	"github.com/urfave/cli"

@@ -63,6 +64,13 @@ command(s) that get executed on start, edit the args parameter of the spec. See

 		},

 	},

 	Action: func(context *cli.Context) error {

+		unified, err := IsCgroup2UnifiedMode()

+		if  err != nil {

+			return err

+		}

+		if unified {

+			return fmt.Errorf("this version of runc doesn't work on cgroups v2")

+		}

 		if err := checkArgs(context, 1, exactArgs); err != nil {

 			return err

 		}

diff --git a/utils_linux.go b/utils_linux.go

index 984e6b0f..a5a03de9 100644

--- a/utils_linux.go

+++ b/utils_linux.go

@@ -9,6 +9,7 @@ import (

 	"os/exec"

 	"path/filepath"

 	"strconv"

+	"syscall"

 	"github.com/opencontainers/runc/libcontainer"

 	"github.com/opencontainers/runc/libcontainer/cgroups/systemd"

@@ -26,6 +27,10 @@ import (

 	"golang.org/x/sys/unix"

 )

+const (

+	_cgroup2SuperMagic = 0x63677270

+)

+

 var errEmptyID = errors.New("container id cannot be empty")

 // loadFactory returns the configured factory instance for execing containers.

@@ -451,3 +456,12 @@ func startContainer(context *cli.Context, spec *specs.Spec, action CtAct, criuOp

 	}

 	return r.run(spec.Process)

 }

+

+// IsCgroup2UnifiedMode returns whether we are running in cgroup 2 cgroup2 mode.

+func IsCgroup2UnifiedMode() (bool, error) {

+	var st syscall.Statfs_t

+	if err := syscall.Statfs("/sys/fs/cgroup", &st); err != nil {

+		return false, err

+	}

+	return st.Type == _cgroup2SuperMagic, nil

+}

-- 

2.21.0