.travis.yml: add cgroup v2 Vagrant box

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

.travis.yml

@@ -1,9 +1,27 @@
+dist: bionic
 language: go
 go:
     - 1.11.x
     - 1.12.x
     - 1.13.x
 
+matrix:
+  include:
+    - env:
+        - VIRTUALBOX_VERSION=6.0
+        - VAGRANT_VERSION=2.2.6
+        - FEDORA_VERSION=31
+      before_install:
+        - cat /proc/cpuinfo
+        - wget -q https://www.virtualbox.org/download/oracle_vbox_2016.asc -O- | sudo apt-key add - && sudo sh -c "echo deb https://download.virtualbox.org/virtualbox/debian $(lsb_release -cs) contrib >> /etc/apt/sources.list" && sudo apt-get update && sudo apt-get install -yq build-essential gcc make linux-headers-$(uname -r) virtualbox-${VIRTUALBOX_VERSION} && sudo usermod -aG vboxusers $(whoami)
+        - wget https://releases.hashicorp.com/vagrant/${VAGRANT_VERSION}/vagrant_${VAGRANT_VERSION}_$(uname -m).deb && sudo dpkg -i vagrant_${VAGRANT_VERSION}_$(uname -m).deb
+        - vagrant init bento/fedora-${FEDORA_VERSION} && vagrant up && mkdir -p ~/.ssh && vagrant ssh-config >> ~/.ssh/config
+        - ssh default sudo dnf install -y golang
+      script:
+        - ssh default sudo mkdir -p /go/src/github.com/containerd/cgroups
+        - cd $GOPATH/src/github.com/containerd/cgroups && tar c . | ssh default sudo tar Cx /go/src/github.com/containerd/cgroups
+        - ssh default sudo GOPATH=/go sh -c "cd /go/src/github.com/containerd/cgroups && go test -v ./..."
+
 go_import_path: github.com/containerd/cgroups
 
 install:

paths_test.go

@@ -114,6 +114,9 @@ func TestEmptySubsystem(t *testing.T) {
 }
 
 func TestSystemd240(t *testing.T) {
+	if isUnified {
+		t.Skipf("requires the system to be running in legacy mode")
+	}
 	const data = `8:net_cls:/
 	7:memory:/system.slice/docker.service
 	6:freezer:/

testutil_test.go

@@ -0,0 +1,30 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package cgroups
+
+import (
+	"golang.org/x/sys/unix"
+)
+
+var isUnified bool
+
+func init() {
+	var st unix.Statfs_t
+	if err := unix.Statfs("/sys/fs/cgroup", &st); err == nil {
+		isUnified = st.Type == unix.CGROUP2_SUPER_MAGIC
+	}
+}