Add test for function based hooks

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

libcontainer/configs/config.go

@@ -194,12 +194,16 @@ type Hook interface {
 // NewFunctionHooks will call the provided function when the hook is run.
 func NewFunctionHook(f func(*HookState) error) *FuncHook {
 	return &FuncHook{
-		Run: f,
+		run: f,
 	}
 }
 
 type FuncHook struct {
-	Run func(*HookState) error
+	run func(*HookState) error
+}
+
+func (f *FuncHook) Run(s *HookState) error {
+	return f.run(s)
 }
 
 type Command struct {

libcontainer/container_linux.go

@@ -185,6 +185,7 @@ func (c *linuxContainer) newInitProcess(p *Process, cmd *exec.Cmd, parentPipe, c
 		parentPipe: parentPipe,
 		manager:    c.cgroupManager,
 		config:     c.newInitConfig(p),
+		container:  c,
 	}, nil
 }
 

libcontainer/integration/exec_test.go

@@ -946,19 +946,24 @@ func TestPrestartHook(t *testing.T) {
 	defer remove(rootfs)
 
 	config := newTemplateConfig(rootfs)
-	pwd, _ := os.Getwd()
-
-	hookPath := filepath.Join(pwd, "../../script", "hook.py")
-	prestartCmd := configs.Command{Path: hookPath}
-	config.Prestart = append(config.Prestart, prestartCmd)
-
+	config.Hooks = &configs.Hooks{
+		Prestart: []configs.Hook{
+			configs.NewFunctionHook(func(s *configs.HookState) error {
+				f, err := os.Create(filepath.Join(rootfs, "test"))
+				if err != nil {
+					return err
+				}
+				return f.Close()
+			}),
+		},
+	}
 	container, err := factory.Create("test", config)
 	ok(t, err)
 	defer container.Destroy()
 
 	var stdout bytes.Buffer
 	pconfig := libcontainer.Process{
-		Args:   []string{"sh", "-c", "ls /tmp.txt"},
+		Args:   []string{"sh", "-c", "ls /test"},
 		Env:    standardEnvironment,
 		Stdin:  nil,
 		Stdout: &stdout,
@@ -972,7 +977,7 @@ func TestPrestartHook(t *testing.T) {
 	outputLs := string(stdout.Bytes())
 
 	// Check that the ls output has the expected file touched by the prestart hook
-	if !strings.Contains(outputLs, "/tmp.txt") {
+	if !strings.Contains(outputLs, "/test") {
 		t.Fatal("ls output doesn't have the expected file: ", outputLs)
 	}
 }

script/hook.py

@@ -1,15 +0,0 @@
-#!/usr/bin/env python
-import sys
-import json
-import os
-
-def touch(filepath):
-	if os.path.exists(filepath):
-		os.utime(filepath, None)
-	else:
-		open(filepath, 'a').close()
-
-if __name__ == "__main__":
-	rootfs = json.load(sys.stdin)["config"]["rootfs"]
-	touch(os.path.join(rootfs, "tmp.txt"))
-