Ensure a reliable way to kill ghost containers on reboot

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

runtime/execdriver/native/driver.go

@@ -117,9 +117,39 @@ func (d *driver) Run(c *execdriver.Command, pipes *execdriver.Pipes, startCallba
 }
 
 func (d *driver) Kill(p *execdriver.Command, sig int) error {
-	err := syscall.Kill(p.Process.Pid, syscall.Signal(sig))
+	return syscall.Kill(p.Process.Pid, syscall.Signal(sig))
+}
+
+func (d *driver) Terminate(p *execdriver.Command) error {
+	// lets check the start time for the process
+	started, err := d.readStartTime(p)
+	if err != nil {
+		// if we don't have the data on disk then we can assume the process is gone
+		// because this is only removed after we know the process has stopped
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+
+	currentStartTime, err := system.GetProcessStartTime(p.Process.Pid)
+	if err != nil {
+		return err
+	}
+	if started == currentStartTime {
+		err = syscall.Kill(p.Process.Pid, 9)
+	}
 	d.removeContainerRoot(p.ID)
 	return err
+
+}
+
+func (d *driver) readStartTime(p *execdriver.Command) (string, error) {
+	data, err := ioutil.ReadFile(filepath.Join(d.root, p.ID, "start"))
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
 }
 
 func (d *driver) Info(id string) execdriver.Info {
@@ -235,9 +265,9 @@ type dockerStateWriter struct {
 	callback execdriver.StartCallback
 }
 
-func (d *dockerStateWriter) WritePid(pid int) error {
+func (d *dockerStateWriter) WritePid(pid int, started string) error {
 	d.c.ContainerPid = pid
-	err := d.dsw.WritePid(pid)
+	err := d.dsw.WritePid(pid, started)
 	if d.callback != nil {
 		d.callback(d.c)
 	}