1 files changed, 69 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/cgroups/freezer.go b/vendor/github.com/containerd/cgroups/freezer.go
new file mode 100644
index 000000000..f53430b51
--- /dev/null
+++ b/vendor/github.com/containerd/cgroups/freezer.go
@@ -0,0 +1,69 @@
+package cgroups
+
+import (
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+func NewFreezer(root string) *freezerController {
+	return &freezerController{
+		root: filepath.Join(root, string(Freezer)),
+	}
+}
+
+type freezerController struct {
+	root string
+}
+
+func (f *freezerController) Name() Name {
+	return Freezer
+}
+
+func (f *freezerController) Path(path string) string {
+	return filepath.Join(f.root, path)
+}
+
+func (f *freezerController) Freeze(path string) error {
+	if err := f.changeState(path, Frozen); err != nil {
+		return err
+	}
+	return f.waitState(path, Frozen)
+}
+
+func (f *freezerController) Thaw(path string) error {
+	if err := f.changeState(path, Thawed); err != nil {
+		return err
+	}
+	return f.waitState(path, Thawed)
+}
+
+func (f *freezerController) changeState(path string, state State) error {
+	return ioutil.WriteFile(
+		filepath.Join(f.root, path, "freezer.state"),
+		[]byte(strings.ToUpper(string(state))),
+		defaultFilePerm,
+	)
+}
+
+func (f *freezerController) state(path string) (State, error) {
+	current, err := ioutil.ReadFile(filepath.Join(f.root, path, "freezer.state"))
+	if err != nil {
+		return "", err
+	}
+	return State(strings.ToLower(strings.TrimSpace(string(current)))), nil
+}
+
+func (f *freezerController) waitState(path string, state State) error {
+	for {
+		current, err := f.state(path)
+		if err != nil {
+			return err
+		}
+		if current == state {
+			return nil
+		}
+		time.Sleep(1 * time.Millisecond)
+	}
+}