patch for issue opencontainers#39:

	runc always shows "container in use" if /var/run/ocf/container exists
	However, there are two cases
		1) case 1: "container in use"
		2) case 2: /var/run/ocf/container still exists after runc was terminated by SIGKILL or abnormal crash
	For case 2, runc should yield "delete the lock dir" instead of "container in use"
	This patch is for this issue using "pid" file in /var/run/ocf/container/task

Signed-off-by: Jin-Hwan Jeong <[email protected]>

libcontainer/factory_linux.go

@@ -159,13 +159,27 @@ func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, err
 	}
 	containerRoot := filepath.Join(l.Root, id)
 	if _, err := os.Stat(containerRoot); err == nil {
-		return nil, newGenericError(fmt.Errorf("Container with id exists: %v", id), IdInUse)
+		pid, err := ioutil.ReadFile(filepath.Join(containerRoot, "task"))
+		if err == nil {
+			procPath := fmt.Sprintf("/proc/%s/cmdline", pid)
+			if cmdline, err := ioutil.ReadFile(procPath); err == nil {
+				_, exeName := filepath.Split(string(cmdline))
+				exeName = exeName[0:4]
+				if exeName[0:4] == "runc" {
+					return nil, newGenericError(fmt.Errorf("Container with id exists: %v", id), IdInUse)
+				}
+			}
+		}
+		return nil, newGenericError(fmt.Errorf("delete the directory: %s", containerRoot), IdInUse)
 	} else if !os.IsNotExist(err) {
 		return nil, newGenericError(err, SystemError)
 	}
 	if err := os.MkdirAll(containerRoot, 0700); err != nil {
 		return nil, newGenericError(err, SystemError)
 	}
+	if err := ioutil.WriteFile(filepath.Join(containerRoot, "task"), []byte(fmt.Sprintf("%d", os.Getpid())), 0700); err != nil {
+		return nil, newGenericError(err, SystemError)
+	}
 	return &linuxContainer{
 		id:            id,
 		root:          containerRoot,