Update nitrokey crate to 0.4.0-alpha.3

This change updates the version of the nitrokey crate that we use to
0.4.0-alpha.3. This version is the supposedly last pre-release before
0.4.0, with no further major anticipated changes.
In order to integrate with this new version we have to adjust the way we
connect to a Nitrokey device by funneling those connection requests
through a global manager object. The rationale behind that step being
that the underlying libnitrokey actually cannot handle access of
multiple devices at the same time, and so the manager object is used to
prevent accidental wrong concurrent usage.
Because a device object now effectively keeps a reference to the
manager, we need to provide an additional lifetime to that and derived
objects.
Lastly, the use of a manager is also the reason why the tests had to be
adjusted to no longer accept device objects in their signatures, but
only the respective model for which to invoke the test. That is required
because, as elaborated earlier on, having a device object implies having
taken a reference to a manager (in that case owned by nitrokey-test),
and that reference clashes with the nitrocli code itself attempting to
take the manager. We side step this problem by merely accepting a Model
object, which can be passed around independently of the manager itself,
meaning that nitrokey-test does not need to hold such a reference while
the test is run.

Import subrepo nitrokey/:nitrokey at f150d59410eefdec2ae69b2422906a3d1d88aa07
Import subrepo nitrokey-sys/:nitrokey-sys at 8695e2c762807e033a86c8d03974b686d20cdd72
Import subrepo lazy-static/:lazy-static at b4b2b16aaa79dd7548e288455a0dbe4065bf4e1a

1 files changed, 156 insertions, 212 deletions

diff --git a/nitrokey/src/device.rs b/nitrokey/src/device.rs
index f6492cd..758d4c1 100644
--- a/nitrokey/src/device.rs
+++ b/nitrokey/src/device.rs
@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: MIT
 
 use std::fmt;
-use std::marker;
 
 use libc;
 use nitrokey_sys;
@@ -54,7 +53,7 @@ impl fmt::Display for VolumeMode {
 
 /// A wrapper for a Nitrokey device of unknown type.
 ///
-/// Use the function [`connect`][] to obtain a wrapped instance.  The wrapper implements all traits
+/// Use the [`connect`][] method to obtain a wrapped instance.  The wrapper implements all traits
 /// that are shared between all Nitrokey devices so that the shared functionality can be used
 /// without knowing the type of the underlying device.  If you want to use functionality that is
 /// not available for all devices, you have to extract the device.
@@ -67,11 +66,12 @@ impl fmt::Display for VolumeMode {
 /// use nitrokey::{Authenticate, DeviceWrapper, User};
 /// # use nitrokey::Error;
 ///
-/// fn perform_user_task(device: &User<DeviceWrapper>) {}
+/// fn perform_user_task<'a>(device: &User<'a, DeviceWrapper<'a>>) {}
 /// fn perform_other_task(device: &DeviceWrapper) {}
 ///
 /// # fn try_main() -> Result<(), Error> {
-/// let device = nitrokey::connect()?;
+/// let mut manager = nitrokey::take()?;
+/// let device = manager.connect()?;
 /// let device = match device.authenticate_user("123456") {
 ///     Ok(user) => {
 ///         perform_user_task(&user);
@@ -97,7 +97,8 @@ impl fmt::Display for VolumeMode {
 /// fn perform_storage_task(device: &Storage) {}
 ///
 /// # fn try_main() -> Result<(), Error> {
-/// let device = nitrokey::connect()?;
+/// let mut manager = nitrokey::take()?;
+/// let device = manager.connect()?;
 /// perform_common_task(&device);
 /// match device {
 ///     DeviceWrapper::Storage(storage) => perform_storage_task(&storage),
@@ -107,21 +108,20 @@ impl fmt::Display for VolumeMode {
 /// # }
 /// ```
 ///
-/// [`connect`]: fn.connect.html
+/// [`connect`]: struct.Manager.html#method.connect
 #[derive(Debug)]
-pub enum DeviceWrapper {
+pub enum DeviceWrapper<'a> {
     /// A Nitrokey Storage device.
-    Storage(Storage),
+    Storage(Storage<'a>),
     /// A Nitrokey Pro device.
-    Pro(Pro),
+    Pro(Pro<'a>),
 }
 
 /// A Nitrokey Pro device without user or admin authentication.
 ///
-/// Use the global function [`connect`][] to obtain an instance wrapper or the method
-/// [`connect`][`Pro::connect`] to directly obtain an instance.  If you want to execute a command
-/// that requires user or admin authentication, use [`authenticate_admin`][] or
-/// [`authenticate_user`][].
+/// Use the [`connect`][] method to obtain an instance wrapper or the [`connect_pro`] method to
+/// directly obtain an instance.  If you want to execute a command that requires user or admin
+/// authentication, use [`authenticate_admin`][] or [`authenticate_user`][].
 ///
 /// # Examples
 ///
@@ -131,11 +131,12 @@ pub enum DeviceWrapper {
 /// use nitrokey::{Authenticate, User, Pro};
 /// # use nitrokey::Error;
 ///
-/// fn perform_user_task(device: &User<Pro>) {}
+/// fn perform_user_task<'a>(device: &User<'a, Pro<'a>>) {}
 /// fn perform_other_task(device: &Pro) {}
 ///
 /// # fn try_main() -> Result<(), Error> {
-/// let device = nitrokey::Pro::connect()?;
+/// let mut manager = nitrokey::take()?;
+/// let device = manager.connect_pro()?;
 /// let device = match device.authenticate_user("123456") {
 ///     Ok(user) => {
 ///         perform_user_task(&user);
@@ -153,21 +154,18 @@ pub enum DeviceWrapper {
 ///
 /// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
 /// [`authenticate_user`]: trait.Authenticate.html#method.authenticate_user
-/// [`connect`]: fn.connect.html
-/// [`Pro::connect`]: #method.connect
+/// [`connect`]: struct.Manager.html#method.connect
+/// [`connect_pro`]: struct.Manager.html#method.connect_pro
 #[derive(Debug)]
-pub struct Pro {
-    // make sure that users cannot directly instantiate this type
-    #[doc(hidden)]
-    marker: marker::PhantomData<()>,
+pub struct Pro<'a> {
+    manager: Option<&'a mut crate::Manager>,
 }
 
 /// A Nitrokey Storage device without user or admin authentication.
 ///
-/// Use the global function [`connect`][] to obtain an instance wrapper or the method
-/// [`connect`][`Storage::connect`] to directly obtain an instance.  If you want to execute a
-/// command that requires user or admin authentication, use [`authenticate_admin`][] or
-/// [`authenticate_user`][].
+/// Use the [`connect`][] method to obtain an instance wrapper or the [`connect_storage`] method to
+/// directly obtain an instance.  If you want to execute a command that requires user or admin
+/// authentication, use [`authenticate_admin`][] or [`authenticate_user`][].
 ///
 /// # Examples
 ///
@@ -177,11 +175,12 @@ pub struct Pro {
 /// use nitrokey::{Authenticate, User, Storage};
 /// # use nitrokey::Error;
 ///
-/// fn perform_user_task(device: &User<Storage>) {}
+/// fn perform_user_task<'a>(device: &User<'a, Storage<'a>>) {}
 /// fn perform_other_task(device: &Storage) {}
 ///
 /// # fn try_main() -> Result<(), Error> {
-/// let device = nitrokey::Storage::connect()?;
+/// let mut manager = nitrokey::take()?;
+/// let device = manager.connect_storage()?;
 /// let device = match device.authenticate_user("123456") {
 ///     Ok(user) => {
 ///         perform_user_task(&user);
@@ -199,13 +198,11 @@ pub struct Pro {
 ///
 /// [`authenticate_admin`]: trait.Authenticate.html#method.authenticate_admin
 /// [`authenticate_user`]: trait.Authenticate.html#method.authenticate_user
-/// [`connect`]: fn.connect.html
-/// [`Storage::connect`]: #method.connect
+/// [`connect`]: struct.Manager.html#method.connect
+/// [`connect_storage`]: struct.Manager.html#method.connect_storage
 #[derive(Debug)]
-pub struct Storage {
-    // make sure that users cannot directly instantiate this type
-    #[doc(hidden)]
-    marker: marker::PhantomData<()>,
+pub struct Storage<'a> {
+    manager: Option<&'a mut crate::Manager>,
 }
 
 /// The status of a volume on a Nitrokey Storage device.
@@ -296,7 +293,32 @@ pub struct StorageStatus {
 ///
 /// This trait provides the commands that can be executed without authentication and that are
 /// present on all supported Nitrokey devices.
-pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
+pub trait Device<'a>: Authenticate<'a> + GetPasswordSafe<'a> + GenerateOtp + fmt::Debug {
+    /// Returns the [`Manager`][] instance that has been used to connect to this device.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use nitrokey::{Device, DeviceWrapper};
+    ///
+    /// fn do_something(device: DeviceWrapper) {
+    ///     // reconnect to any device
+    ///     let manager = device.into_manager();
+    ///     let device = manager.connect();
+    ///     // do something with the device
+    ///     // ...
+    /// }
+    ///
+    /// # fn main() -> Result<(), nitrokey::Error> {
+    /// match nitrokey::take()?.connect() {
+    ///     Ok(device) => do_something(device),
+    ///     Err(err) => println!("Could not connect to a Nitrokey: {}", err),
+    /// }
+    /// #     Ok(())
+    /// # }
+    /// ```
+    fn into_manager(self) -> &'a mut crate::Manager;
+
     /// Returns the model of the connected Nitrokey device.
     ///
     /// # Example
@@ -306,7 +328,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
     /// println!("Connected to a Nitrokey {}", device.get_model());
     /// #    Ok(())
     /// # }
@@ -322,7 +345,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
     /// match device.get_serial_number() {
     ///     Ok(number) => println!("serial no: {}", number),
     ///     Err(err) => eprintln!("Could not get serial number: {}", err),
@@ -344,7 +368,9 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
+    /// let count = device.get_user_retry_count();
     /// match device.get_user_retry_count() {
     ///     Ok(count) => println!("{} remaining authentication attempts (user)", count),
     ///     Err(err) => eprintln!("Could not get user retry count: {}", err),
@@ -366,7 +392,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
     /// let count = device.get_admin_retry_count();
     /// match device.get_admin_retry_count() {
     ///     Ok(count) => println!("{} remaining authentication attempts (admin)", count),
@@ -388,7 +415,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
     /// match device.get_firmware_version() {
     ///     Ok(version) => println!("Firmware version: {}", version),
     ///     Err(err) => eprintln!("Could not access firmware version: {}", err),
@@ -399,14 +427,7 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     fn get_firmware_version(&self) -> Result<FirmwareVersion, Error> {
         let major = result_or_error(unsafe { nitrokey_sys::NK_get_major_firmware_version() })?;
         let minor = result_or_error(unsafe { nitrokey_sys::NK_get_minor_firmware_version() })?;
-        let max = i32::from(u8::max_value());
-        if major < 0 || minor < 0 || major > max || minor > max {
-            return Err(Error::UnexpectedError);
-        }
-        Ok(FirmwareVersion {
-            major: major as u8,
-            minor: minor as u8,
-        })
+        Ok(FirmwareVersion { major, minor })
     }
 
     /// Returns the current configuration of the Nitrokey device.
@@ -418,7 +439,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
     /// let config = device.get_config()?;
     /// println!("numlock binding:          {:?}", config.numlock);
     /// println!("capslock binding:         {:?}", config.capslock);
@@ -452,7 +474,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.change_admin_pin("12345678", "12345679") {
     ///     Ok(()) => println!("Updated admin PIN."),
     ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
@@ -485,7 +508,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.change_user_pin("123456", "123457") {
     ///     Ok(()) => println!("Updated admin PIN."),
     ///     Err(err) => eprintln!("Failed to update admin PIN: {}", err),
@@ -518,7 +542,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.unlock_user_pin("12345678", "123456") {
     ///     Ok(()) => println!("Unlocked user PIN."),
     ///     Err(err) => eprintln!("Failed to unlock user PIN: {}", err),
@@ -552,7 +577,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.lock() {
     ///     Ok(()) => println!("Locked the Nitrokey device."),
     ///     Err(err) => eprintln!("Could not lock the Nitrokey device: {}", err),
@@ -583,7 +609,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.factory_reset("12345678") {
     ///     Ok(()) => println!("Performed a factory reset."),
     ///     Err(err) => eprintln!("Could not perform a factory reset: {}", err),
@@ -617,7 +644,8 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect()?;
     /// match device.build_aes_key("12345678") {
     ///     Ok(()) => println!("New AES keys have been built."),
     ///     Err(err) => eprintln!("Could not build new AES keys: {}", err),
@@ -633,67 +661,6 @@ pub trait Device: Authenticate + GetPasswordSafe + GenerateOtp + fmt::Debug {
     }
 }
 
-/// Connects to a Nitrokey device.  This method can be used to connect to any connected device,
-/// both a Nitrokey Pro and a Nitrokey Storage.
-///
-/// # Errors
-///
-/// - [`NotConnected`][] if no Nitrokey device is connected
-///
-/// # Example
-///
-/// ```
-/// use nitrokey::DeviceWrapper;
-///
-/// fn do_something(device: DeviceWrapper) {}
-///
-/// match nitrokey::connect() {
-///     Ok(device) => do_something(device),
-///     Err(err) => eprintln!("Could not connect to a Nitrokey: {}", err),
-/// }
-/// ```
-///
-/// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-pub fn connect() -> Result<DeviceWrapper, Error> {
-    if unsafe { nitrokey_sys::NK_login_auto() } == 1 {
-        match get_connected_device() {
-            Some(wrapper) => Ok(wrapper),
-            None => Err(CommunicationError::NotConnected.into()),
-        }
-    } else {
-        Err(CommunicationError::NotConnected.into())
-    }
-}
-
-/// Connects to a Nitrokey device of the given model.
-///
-/// # Errors
-///
-/// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-///
-/// # Example
-///
-/// ```
-/// use nitrokey::DeviceWrapper;
-/// use nitrokey::Model;
-///
-/// fn do_something(device: DeviceWrapper) {}
-///
-/// match nitrokey::connect_model(Model::Pro) {
-///     Ok(device) => do_something(device),
-///     Err(err) => eprintln!("Could not connect to a Nitrokey Pro: {}", err),
-/// }
-/// ```
-///
-/// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-pub fn connect_model(model: Model) -> Result<DeviceWrapper, Error> {
-    if connect_enum(model) {
-        Ok(create_device_wrapper(model))
-    } else {
-        Err(CommunicationError::NotConnected.into())
-    }
-}
-
 fn get_connected_model() -> Option<Model> {
     match unsafe { nitrokey_sys::NK_get_device_model() } {
         nitrokey_sys::NK_device_model_NK_PRO => Some(Model::Pro),
@@ -702,18 +669,26 @@ fn get_connected_model() -> Option<Model> {
     }
 }
 
-fn create_device_wrapper(model: Model) -> DeviceWrapper {
+pub(crate) fn create_device_wrapper(
+    manager: &mut crate::Manager,
+    model: Model,
+) -> DeviceWrapper<'_> {
     match model {
-        Model::Pro => Pro::new().into(),
-        Model::Storage => Storage::new().into(),
+        Model::Pro => Pro::new(manager).into(),
+        Model::Storage => Storage::new(manager).into(),
     }
 }
 
-fn get_connected_device() -> Option<DeviceWrapper> {
-    get_connected_model().map(create_device_wrapper)
+pub(crate) fn get_connected_device(
+    manager: &mut crate::Manager,
+) -> Result<DeviceWrapper<'_>, Error> {
+    match get_connected_model() {
+        Some(model) => Ok(create_device_wrapper(manager, model)),
+        None => Err(CommunicationError::NotConnected.into()),
+    }
 }
 
-fn connect_enum(model: Model) -> bool {
+pub(crate) fn connect_enum(model: Model) -> bool {
     let model = match model {
         Model::Storage => nitrokey_sys::NK_device_model_NK_STORAGE,
         Model::Pro => nitrokey_sys::NK_device_model_NK_PRO,
@@ -721,15 +696,15 @@ fn connect_enum(model: Model) -> bool {
     unsafe { nitrokey_sys::NK_login_enum(model) == 1 }
 }
 
-impl DeviceWrapper {
-    fn device(&self) -> &dyn Device {
+impl<'a> DeviceWrapper<'a> {
+    fn device(&self) -> &dyn Device<'a> {
         match *self {
             DeviceWrapper::Storage(ref storage) => storage,
             DeviceWrapper::Pro(ref pro) => pro,
         }
     }
 
-    fn device_mut(&mut self) -> &mut dyn Device {
+    fn device_mut(&mut self) -> &mut dyn Device<'a> {
         match *self {
             DeviceWrapper::Storage(ref mut storage) => storage,
             DeviceWrapper::Pro(ref mut pro) => pro,
@@ -737,19 +712,19 @@ impl DeviceWrapper {
     }
 }
 
-impl From<Pro> for DeviceWrapper {
-    fn from(device: Pro) -> Self {
+impl<'a> From<Pro<'a>> for DeviceWrapper<'a> {
+    fn from(device: Pro<'a>) -> Self {
         DeviceWrapper::Pro(device)
     }
 }
 
-impl From<Storage> for DeviceWrapper {
-    fn from(device: Storage) -> Self {
+impl<'a> From<Storage<'a>> for DeviceWrapper<'a> {
+    fn from(device: Storage<'a>) -> Self {
         DeviceWrapper::Storage(device)
     }
 }
 
-impl GenerateOtp for DeviceWrapper {
+impl<'a> GenerateOtp for DeviceWrapper<'a> {
     fn get_hotp_slot_name(&self, slot: u8) -> Result<String, Error> {
         self.device().get_hotp_slot_name(slot)
     }
@@ -767,7 +742,14 @@ impl GenerateOtp for DeviceWrapper {
     }
 }
 
-impl Device for DeviceWrapper {
+impl<'a> Device<'a> for DeviceWrapper<'a> {
+    fn into_manager(self) -> &'a mut crate::Manager {
+        match self {
+            DeviceWrapper::Pro(dev) => dev.into_manager(),
+            DeviceWrapper::Storage(dev) => dev.into_manager(),
+        }
+    }
+
     fn get_model(&self) -> Model {
         match *self {
             DeviceWrapper::Pro(_) => Model::Pro,
@@ -776,44 +758,15 @@ impl Device for DeviceWrapper {
     }
 }
 
-impl Pro {
-    /// Connects to a Nitrokey Pro.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::Pro;
-    ///
-    /// fn use_pro(device: Pro) {}
-    ///
-    /// match nitrokey::Pro::connect() {
-    ///     Ok(device) => use_pro(device),
-    ///     Err(err) => eprintln!("Could not connect to the Nitrokey Pro: {}", err),
-    /// }
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect() -> Result<Pro, Error> {
-        // TODO: maybe Option instead of Result?
-        if connect_enum(Model::Pro) {
-            Ok(Pro::new())
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-
-    fn new() -> Pro {
+impl<'a> Pro<'a> {
+    pub(crate) fn new(manager: &'a mut crate::Manager) -> Pro<'a> {
         Pro {
-            marker: marker::PhantomData,
+            manager: Some(manager),
         }
     }
 }
 
-impl Drop for Pro {
+impl<'a> Drop for Pro<'a> {
     fn drop(&mut self) {
         unsafe {
             nitrokey_sys::NK_logout();
@@ -821,47 +774,22 @@ impl Drop for Pro {
     }
 }
 
-impl Device for Pro {
+impl<'a> Device<'a> for Pro<'a> {
+    fn into_manager(mut self) -> &'a mut crate::Manager {
+        self.manager.take().unwrap()
+    }
+
     fn get_model(&self) -> Model {
         Model::Pro
     }
 }
 
-impl GenerateOtp for Pro {}
+impl<'a> GenerateOtp for Pro<'a> {}
 
-impl Storage {
-    /// Connects to a Nitrokey Storage.
-    ///
-    /// # Errors
-    ///
-    /// - [`NotConnected`][] if no Nitrokey device of the given model is connected
-    ///
-    /// # Example
-    ///
-    /// ```
-    /// use nitrokey::Storage;
-    ///
-    /// fn use_storage(device: Storage) {}
-    ///
-    /// match nitrokey::Storage::connect() {
-    ///     Ok(device) => use_storage(device),
-    ///     Err(err) => eprintln!("Could not connect to the Nitrokey Storage: {}", err),
-    /// }
-    /// ```
-    ///
-    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
-    pub fn connect() -> Result<Storage, Error> {
-        // TODO: maybe Option instead of Result?
-        if connect_enum(Model::Storage) {
-            Ok(Storage::new())
-        } else {
-            Err(CommunicationError::NotConnected.into())
-        }
-    }
-
-    fn new() -> Storage {
+impl<'a> Storage<'a> {
+    pub(crate) fn new(manager: &'a mut crate::Manager) -> Storage<'a> {
         Storage {
-            marker: marker::PhantomData,
+            manager: Some(manager),
         }
     }
 
@@ -882,7 +810,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.change_update_pin("12345678", "87654321") {
     ///     Ok(()) => println!("Updated update PIN."),
     ///     Err(err) => eprintln!("Failed to update update PIN: {}", err),
@@ -919,7 +848,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.enable_firmware_update("12345678") {
     ///     Ok(()) => println!("Nitrokey entered update mode."),
     ///     Err(err) => eprintln!("Could not enter update mode: {}", err),
@@ -953,7 +883,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.enable_encrypted_volume("123456") {
     ///     Ok(()) => println!("Enabled the encrypted volume."),
     ///     Err(err) => eprintln!("Could not enable the encrypted volume: {}", err),
@@ -982,7 +913,8 @@ impl Storage {
     /// fn use_volume() {}
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.enable_encrypted_volume("123456") {
     ///     Ok(()) => {
     ///         println!("Enabled the encrypted volume.");
@@ -1028,7 +960,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// device.enable_encrypted_volume("123445")?;
     /// match device.enable_hidden_volume("hidden-pw") {
     ///     Ok(()) => println!("Enabled a hidden volume."),
@@ -1061,7 +994,8 @@ impl Storage {
     /// fn use_volume() {}
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// device.enable_encrypted_volume("123445")?;
     /// match device.enable_hidden_volume("hidden-pw") {
     ///     Ok(()) => {
@@ -1108,7 +1042,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// device.enable_encrypted_volume("123445")?;
     /// device.create_hidden_volume(0, 0, 100, "hidden-pw")?;
     /// #     Ok(())
@@ -1148,7 +1083,8 @@ impl Storage {
     /// use nitrokey::VolumeMode;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.set_unencrypted_volume_mode("12345678", VolumeMode::ReadWrite) {
     ///     Ok(()) => println!("Set the unencrypted volume to read-write mode."),
     ///     Err(err) => eprintln!("Could not set the unencrypted volume to read-write mode: {}", err),
@@ -1193,7 +1129,8 @@ impl Storage {
     /// use nitrokey::VolumeMode;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.set_encrypted_volume_mode("12345678", VolumeMode::ReadWrite) {
     ///     Ok(()) => println!("Set the encrypted volume to read-write mode."),
     ///     Err(err) => eprintln!("Could not set the encrypted volume to read-write mode: {}", err),
@@ -1231,7 +1168,8 @@ impl Storage {
     /// fn use_volume() {}
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect_storage()?;
     /// match device.get_status() {
     ///     Ok(status) => {
     ///         println!("SD card ID: {:#x}", status.serial_number_sd_card);
@@ -1274,7 +1212,8 @@ impl Storage {
     /// fn use_volume() {}
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect_storage()?;
     /// match device.get_production_info() {
     ///     Ok(data) => {
     ///         println!("SD card ID:   {:#x}", data.sd_card.serial_number);
@@ -1322,7 +1261,8 @@ impl Storage {
     /// # use nitrokey::Error;
     ///
     /// # fn try_main() -> Result<(), Error> {
-    /// let mut device = nitrokey::Storage::connect()?;
+    /// let mut manager = nitrokey::take()?;
+    /// let mut device = manager.connect_storage()?;
     /// match device.clear_new_sd_card_warning("12345678") {
     ///     Ok(()) => println!("Cleared the new SD card warning."),
     ///     Err(err) => eprintln!("Could not set the clear the new SD card warning: {}", err),
@@ -1367,7 +1307,7 @@ impl Storage {
     }
 }
 
-impl Drop for Storage {
+impl<'a> Drop for Storage<'a> {
     fn drop(&mut self) {
         unsafe {
             nitrokey_sys::NK_logout();
@@ -1375,13 +1315,17 @@ impl Drop for Storage {
     }
 }
 
-impl Device for Storage {
+impl<'a> Device<'a> for Storage<'a> {
+    fn into_manager(mut self) -> &'a mut crate::Manager {
+        self.manager.take().unwrap()
+    }
+
     fn get_model(&self) -> Model {
         Model::Storage
     }
 }
 
-impl GenerateOtp for Storage {}
+impl<'a> GenerateOtp for Storage<'a> {}
 
 impl From<nitrokey_sys::NK_storage_ProductionTest> for StorageProductionInfo {
     fn from(data: nitrokey_sys::NK_storage_ProductionTest) -> Self {