Merge branch 'release-0.5.0'

6 files changed, 510 insertions, 27 deletions

diff --git a/src/device/mod.rs b/src/device/mod.rs
index 5e15f08..16d6b11 100644
--- a/src/device/mod.rs
+++ b/src/device/mod.rs
@@ -5,6 +5,9 @@ mod pro;
 mod storage;
 mod wrapper;
 
+use std::cmp;
+use std::convert::{TryFrom, TryInto};
+use std::ffi;
 use std::fmt;
 
 use libc;
@@ -16,12 +19,14 @@ use crate::error::{CommunicationError, Error};
 use crate::otp::GenerateOtp;
 use crate::pws::GetPasswordSafe;
 use crate::util::{
-    get_command_result, get_cstring, get_last_error, result_from_string, result_or_error,
+    get_command_result, get_cstring, get_last_error, owned_str_from_ptr, result_from_string,
+    result_or_error,
 };
 
 pub use pro::Pro;
 pub use storage::{
-    SdCardData, Storage, StorageProductionInfo, StorageStatus, VolumeMode, VolumeStatus,
+    OperationStatus, SdCardData, Storage, StorageProductionInfo, StorageStatus, VolumeMode,
+    VolumeStatus,
 };
 pub use wrapper::DeviceWrapper;
 
@@ -43,6 +48,97 @@ impl fmt::Display for Model {
     }
 }
 
+impl From<Model> for nitrokey_sys::NK_device_model {
+    fn from(model: Model) -> Self {
+        match model {
+            Model::Storage => nitrokey_sys::NK_device_model_NK_STORAGE,
+            Model::Pro => nitrokey_sys::NK_device_model_NK_PRO,
+        }
+    }
+}
+
+impl TryFrom<nitrokey_sys::NK_device_model> for Model {
+    type Error = Error;
+
+    fn try_from(model: nitrokey_sys::NK_device_model) -> Result<Self, Error> {
+        match model {
+            nitrokey_sys::NK_device_model_NK_DISCONNECTED => {
+                Err(CommunicationError::NotConnected.into())
+            }
+            nitrokey_sys::NK_device_model_NK_PRO => Ok(Model::Pro),
+            nitrokey_sys::NK_device_model_NK_STORAGE => Ok(Model::Storage),
+            _ => Err(Error::UnsupportedModelError),
+        }
+    }
+}
+
+/// Connection information for a Nitrokey device.
+#[derive(Clone, Debug, PartialEq)]
+pub struct DeviceInfo {
+    /// The model of the Nitrokey device, or `None` if the model is not supported by this crate.
+    pub model: Option<Model>,
+    /// The USB device path.
+    pub path: String,
+    /// The serial number as a 8-character hex string, or `None` if the device does not expose its
+    /// serial number.
+    pub serial_number: Option<String>,
+}
+
+impl TryFrom<&nitrokey_sys::NK_device_info> for DeviceInfo {
+    type Error = Error;
+
+    fn try_from(device_info: &nitrokey_sys::NK_device_info) -> Result<DeviceInfo, Error> {
+        let model_result = device_info.model.try_into();
+        let model_option = model_result.map(Some).or_else(|err| match err {
+            Error::UnsupportedModelError => Ok(None),
+            _ => Err(err),
+        })?;
+        let serial_number = unsafe { ffi::CStr::from_ptr(device_info.serial_number) }
+            .to_str()
+            .map_err(Error::from)?;
+        Ok(DeviceInfo {
+            model: model_option,
+            path: owned_str_from_ptr(device_info.path)?,
+            serial_number: get_hidapi_serial_number(serial_number),
+        })
+    }
+}
+
+impl fmt::Display for DeviceInfo {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.model {
+            Some(model) => write!(f, "Nitrokey {}", model)?,
+            None => write!(f, "Unsupported Nitrokey model")?,
+        }
+        write!(f, " at {} with ", self.path)?;
+        match &self.serial_number {
+            Some(ref serial_number) => write!(f, "serial no. {}", serial_number),
+            None => write!(f, "an unknown serial number"),
+        }
+    }
+}
+
+/// Parses a serial number returned by hidapi and transforms it to the Nitrokey format.
+///
+/// If the serial number is all zero, this function returns `None`.  Otherwise, all leading zeros
+/// (except the last eight characters) are stripped and `Some(_)` is returned.  If the serial
+/// number has less than eight characters, leading zeros are added.
+fn get_hidapi_serial_number(serial_number: &str) -> Option<String> {
+    let mut iter = serial_number.char_indices().skip_while(|(_, c)| *c == '0');
+    let first_non_null = iter.next();
+    if let Some((i, _)) = first_non_null {
+        // keep at least the last 8 characters
+        let len = serial_number.len();
+        let cut = cmp::min(len.saturating_sub(8), i);
+        let (_, suffix) = serial_number.split_at(cut);
+        // if necessary, add leading zeros to reach 8 characters
+        let fill = 8usize.saturating_sub(len);
+        Some("0".repeat(fill) + suffix)
+    } else {
+        None
+    }
+}
+
 /// A firmware version for a Nitrokey device.
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct FirmwareVersion {
@@ -58,6 +154,36 @@ impl fmt::Display for FirmwareVersion {
     }
 }
 
+/// The status information common to all Nitrokey devices.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Status {
+    /// The firmware version of the device.
+    pub firmware_version: FirmwareVersion,
+    /// The serial number of the device.
+    pub serial_number: u32,
+    /// The configuration of the device.
+    pub config: Config,
+}
+
+impl From<nitrokey_sys::NK_status> for Status {
+    fn from(status: nitrokey_sys::NK_status) -> Self {
+        Self {
+            firmware_version: FirmwareVersion {
+                major: status.firmware_version_major,
+                minor: status.firmware_version_minor,
+            },
+            serial_number: status.serial_number_smart_card,
+            config: RawConfig {
+                numlock: status.config_numlock,
+                capslock: status.config_capslock,
+                scrollock: status.config_scrolllock,
+                user_password: status.otp_user_password,
+            }
+            .into(),
+        }
+    }
+}
+
 /// A Nitrokey device.
 ///
 /// This trait provides the commands that can be executed without authentication and that are
@@ -102,6 +228,35 @@ pub trait Device<'a>: Authenticate<'a> + GetPasswordSafe<'a> + GenerateOtp + fmt
     /// # }
     fn get_model(&self) -> Model;
 
+    /// Returns the status of the Nitrokey device.
+    ///
+    /// This methods returns the status information common to all Nitrokey devices as a
+    /// [`Status`][] struct.  Some models may provide more information, for example
+    /// [`get_storage_status`][] returns the [`StorageStatus`][] struct.
+    ///
+    /// # Errors
+    ///
+    /// - [`NotConnected`][] if the Nitrokey device has been disconnected
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// use nitrokey::Device;
+    ///
+    /// let mut manager = nitrokey::take()?;
+    /// let device = manager.connect()?;
+    /// let status = device.get_status()?;
+    /// println!("Firmware version: {}", status.firmware_version);
+    /// println!("Serial number:    {:x}", status.serial_number);
+    /// # Ok::<(), nitrokey::Error>(())
+    /// ```
+    ///
+    /// [`get_storage_status`]: struct.Storage.html#method.get_storage_status
+    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
+    /// [`Status`]: struct.Status.html
+    /// [`StorageStatus`]: struct.StorageStatus.html
+    fn get_status(&self) -> Result<Status, Error>;
+
     /// Returns the serial number of the Nitrokey device.  The serial number is the string
     /// representation of a hex number.
     ///
@@ -428,12 +583,8 @@ pub trait Device<'a>: Authenticate<'a> + GetPasswordSafe<'a> + GenerateOtp + fmt
     }
 }
 
-fn get_connected_model() -> Option<Model> {
-    match unsafe { nitrokey_sys::NK_get_device_model() } {
-        nitrokey_sys::NK_device_model_NK_PRO => Some(Model::Pro),
-        nitrokey_sys::NK_device_model_NK_STORAGE => Some(Model::Storage),
-        _ => None,
-    }
+fn get_connected_model() -> Result<Model, Error> {
+    Model::try_from(unsafe { nitrokey_sys::NK_get_device_model() })
 }
 
 pub(crate) fn create_device_wrapper(
@@ -449,16 +600,40 @@ pub(crate) fn 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()),
-    }
+    Ok(create_device_wrapper(manager, get_connected_model()?))
 }
 
 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,
-    };
-    unsafe { nitrokey_sys::NK_login_enum(model) == 1 }
+    unsafe { nitrokey_sys::NK_login_enum(model.into()) == 1 }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::get_hidapi_serial_number;
+
+    #[test]
+    fn hidapi_serial_number() {
+        assert_eq!(None, get_hidapi_serial_number(""));
+        assert_eq!(None, get_hidapi_serial_number("00000000000000000"));
+        assert_eq!(
+            Some("00001234".to_string()),
+            get_hidapi_serial_number("1234")
+        );
+        assert_eq!(
+            Some("00001234".to_string()),
+            get_hidapi_serial_number("00001234")
+        );
+        assert_eq!(
+            Some("00001234".to_string()),
+            get_hidapi_serial_number("000000001234")
+        );
+        assert_eq!(
+            Some("100000001234".to_string()),
+            get_hidapi_serial_number("100000001234")
+        );
+        assert_eq!(
+            Some("10000001234".to_string()),
+            get_hidapi_serial_number("010000001234")
+        );
+    }
 }
diff --git a/src/device/pro.rs b/src/device/pro.rs
index a65345e..591b730 100644
--- a/src/device/pro.rs
+++ b/src/device/pro.rs
@@ -3,8 +3,10 @@
 
 use nitrokey_sys;
 
-use crate::device::{Device, Model};
+use crate::device::{Device, Model, Status};
+use crate::error::Error;
 use crate::otp::GenerateOtp;
+use crate::util::get_command_result;
 
 /// A Nitrokey Pro device without user or admin authentication.
 ///
@@ -74,6 +76,20 @@ impl<'a> Device<'a> for Pro<'a> {
     fn get_model(&self) -> Model {
         Model::Pro
     }
+
+    fn get_status(&self) -> Result<Status, Error> {
+        let mut raw_status = nitrokey_sys::NK_status {
+            firmware_version_major: 0,
+            firmware_version_minor: 0,
+            serial_number_smart_card: 0,
+            config_numlock: 0,
+            config_capslock: 0,
+            config_scrolllock: 0,
+            otp_user_password: false,
+        };
+        get_command_result(unsafe { nitrokey_sys::NK_get_status(&mut raw_status) })?;
+        Ok(raw_status.into())
+    }
 }
 
 impl<'a> GenerateOtp for Pro<'a> {}
diff --git a/src/device/storage.rs b/src/device/storage.rs
index 370ce36..deb2844 100644
--- a/src/device/storage.rs
+++ b/src/device/storage.rs
@@ -1,14 +1,16 @@
-// Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
+// Copyright (C) 2019-2020 Robin Krahl <robin.krahl@ireas.org>
 // SPDX-License-Identifier: MIT
 
+use std::convert::TryFrom as _;
 use std::fmt;
+use std::ops;
 
 use nitrokey_sys;
 
-use crate::device::{Device, FirmwareVersion, Model};
-use crate::error::Error;
+use crate::device::{Device, FirmwareVersion, Model, Status};
+use crate::error::{CommandError, Error};
 use crate::otp::GenerateOtp;
-use crate::util::{get_command_result, get_cstring};
+use crate::util::{get_command_result, get_cstring, get_last_error};
 
 /// A Nitrokey Storage device without user or admin authentication.
 ///
@@ -141,6 +143,20 @@ pub struct StorageStatus {
     pub stick_initialized: bool,
 }
 
+/// The progress of a background operation on the Nitrokey.
+///
+/// Some commands may start a background operation during which no other commands can be executed.
+/// This enum stores the status of a background operation:  Ongoing with a relative progress (up to
+/// 100), or idle, i. e. no background operation has been started or the last one has been
+/// finished.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum OperationStatus {
+    /// A background operation with its progress value (less than or equal to 100).
+    Ongoing(u8),
+    /// No backgrund operation.
+    Idle,
+}
+
 impl<'a> Storage<'a> {
     pub(crate) fn new(manager: &'a mut crate::Manager) -> Storage<'a> {
         Storage {
@@ -525,7 +541,7 @@ impl<'a> Storage<'a> {
     /// # fn try_main() -> Result<(), Error> {
     /// let mut manager = nitrokey::take()?;
     /// let device = manager.connect_storage()?;
-    /// match device.get_status() {
+    /// match device.get_storage_status() {
     ///     Ok(status) => {
     ///         println!("SD card ID: {:#x}", status.serial_number_sd_card);
     ///     },
@@ -534,7 +550,7 @@ impl<'a> Storage<'a> {
     /// #     Ok(())
     /// # }
     /// ```
-    pub fn get_status(&self) -> Result<StorageStatus, Error> {
+    pub fn get_storage_status(&self) -> Result<StorageStatus, Error> {
         let mut raw_status = nitrokey_sys::NK_storage_status {
             unencrypted_volume_read_only: false,
             unencrypted_volume_active: false,
@@ -635,11 +651,117 @@ impl<'a> Storage<'a> {
         })
     }
 
+    /// Returns a range of the SD card that has not been used to during this power cycle.
+    ///
+    /// The Nitrokey Storage tracks read and write access to the SD card during a power cycle.
+    /// This method returns a range of the SD card that has not been accessed during this power
+    /// cycle.  The range is relative to the total size of the SD card, so both values are less
+    /// than or equal to 100.  This can be used as a guideline when creating a hidden volume.
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// let mut manager = nitrokey::take()?;
+    /// let storage = manager.connect_storage()?;
+    /// let usage = storage.get_sd_card_usage()?;
+    /// println!("SD card usage: {}..{}", usage.start, usage.end);
+    /// # Ok::<(), nitrokey::Error>(())
+    /// ```
+    pub fn get_sd_card_usage(&self) -> Result<ops::Range<u8>, Error> {
+        let mut usage_data = nitrokey_sys::NK_SD_usage_data {
+            write_level_min: 0,
+            write_level_max: 0,
+        };
+        let result = unsafe { nitrokey_sys::NK_get_SD_usage_data(&mut usage_data) };
+        match get_command_result(result) {
+            Ok(_) => {
+                if usage_data.write_level_min > usage_data.write_level_max
+                    || usage_data.write_level_max > 100
+                {
+                    Err(Error::UnexpectedError)
+                } else {
+                    Ok(ops::Range {
+                        start: usage_data.write_level_min,
+                        end: usage_data.write_level_max,
+                    })
+                }
+            }
+            Err(err) => Err(err),
+        }
+    }
+
     /// Blinks the red and green LED alternatively and infinitely until the device is reconnected.
     pub fn wink(&mut self) -> Result<(), Error> {
         get_command_result(unsafe { nitrokey_sys::NK_wink() })
     }
 
+    /// Returns the status of an ongoing background operation on the Nitrokey Storage.
+    ///
+    /// Some commands may start a background operation during which no other commands can be
+    /// executed.  This method can be used to check whether such an operation is ongoing.
+    ///
+    /// Currently, this is only used by the [`fill_sd_card`][] method.
+    ///
+    /// [`fill_sd_card`]: #method.fill_sd_card
+    pub fn get_operation_status(&self) -> Result<OperationStatus, Error> {
+        let status = unsafe { nitrokey_sys::NK_get_progress_bar_value() };
+        match status {
+            0..=100 => u8::try_from(status)
+                .map(OperationStatus::Ongoing)
+                .map_err(|_| Error::UnexpectedError),
+            -1 => Ok(OperationStatus::Idle),
+            -2 => Err(get_last_error()),
+            _ => Err(Error::UnexpectedError),
+        }
+    }
+
+    /// Overwrites the SD card with random data.
+    ///
+    /// Ths method starts a background operation that overwrites the SD card with random data.
+    /// While this operation is ongoing, no other commands can be executed.  Use the
+    /// [`get_operation_status`][] function to check the progress of the operation.
+    ///
+    /// # Errors
+    ///
+    /// - [`InvalidString`][] if one of the provided passwords contains a null byte
+    /// - [`WrongPassword`][] if the admin password is wrong
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// use nitrokey::OperationStatus;
+    ///
+    /// let mut manager = nitrokey::take()?;
+    /// let mut storage = manager.connect_storage()?;
+    /// storage.fill_sd_card("12345678")?;
+    /// loop {
+    ///     match storage.get_operation_status()? {
+    ///         OperationStatus::Ongoing(progress) => println!("{}/100", progress),
+    ///         OperationStatus::Idle => {
+    ///             println!("Done!");
+    ///             break;
+    ///         }
+    ///     }
+    /// }
+    /// # Ok::<(), nitrokey::Error>(())
+    /// ```
+    ///
+    /// [`get_operation_status`]: #method.get_operation_status
+    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
+    /// [`WrongPassword`]: enum.CommandError.html#variant.WrongPassword
+    pub fn fill_sd_card(&mut self, admin_pin: &str) -> Result<(), Error> {
+        let admin_pin_string = get_cstring(admin_pin)?;
+        get_command_result(unsafe {
+            nitrokey_sys::NK_fill_SD_card_with_random_data(admin_pin_string.as_ptr())
+        })
+        .or_else(|err| match err {
+            // libnitrokey’s C API returns a LongOperationInProgressException with the same error
+            // code as the WrongCrc command error, so we cannot distinguish them.
+            Error::CommandError(CommandError::WrongCrc) => Ok(()),
+            err => Err(err),
+        })
+    }
+
     /// Exports the firmware to the unencrypted volume.
     ///
     /// This command requires the admin PIN.  The unencrypted volume must be in read-write mode
@@ -678,6 +800,33 @@ impl<'a> Device<'a> for Storage<'a> {
     fn get_model(&self) -> Model {
         Model::Storage
     }
+
+    fn get_status(&self) -> Result<Status, Error> {
+        // Currently, the GET_STATUS command does not report the correct firmware version and
+        // serial number on the Nitrokey Storage, see [0].  Until this is fixed in libnitrokey, we
+        // have to manually execute the GET_DEVICE_STATUS command (get_storage_status) and complete
+        // the missing data, see [1].
+        // [0] https://github.com/Nitrokey/nitrokey-storage-firmware/issues/96
+        // [1] https://github.com/Nitrokey/libnitrokey/issues/166
+
+        let mut raw_status = nitrokey_sys::NK_status {
+            firmware_version_major: 0,
+            firmware_version_minor: 0,
+            serial_number_smart_card: 0,
+            config_numlock: 0,
+            config_capslock: 0,
+            config_scrolllock: 0,
+            otp_user_password: false,
+        };
+        get_command_result(unsafe { nitrokey_sys::NK_get_status(&mut raw_status) })?;
+        let mut status = Status::from(raw_status);
+
+        let storage_status = self.get_storage_status()?;
+        status.firmware_version = storage_status.firmware_version;
+        status.serial_number = storage_status.serial_number_smart_card;
+
+        Ok(status)
+    }
 }
 
 impl<'a> GenerateOtp for Storage<'a> {}
diff --git a/src/device/wrapper.rs b/src/device/wrapper.rs
index a3a18f9..69291ad 100644
--- a/src/device/wrapper.rs
+++ b/src/device/wrapper.rs
@@ -1,7 +1,7 @@
 // Copyright (C) 2018-2019 Robin Krahl <robin.krahl@ireas.org>
 // SPDX-License-Identifier: MIT
 
-use crate::device::{Device, Model, Pro, Storage};
+use crate::device::{Device, Model, Pro, Status, Storage};
 use crate::error::Error;
 use crate::otp::GenerateOtp;
 
@@ -131,4 +131,11 @@ impl<'a> Device<'a> for DeviceWrapper<'a> {
             DeviceWrapper::Storage(_) => Model::Storage,
         }
     }
+
+    fn get_status(&self) -> Result<Status, Error> {
+        match self {
+            DeviceWrapper::Pro(dev) => dev.get_status(),
+            DeviceWrapper::Storage(dev) => dev.get_status(),
+        }
+    }
 }
diff --git a/src/error.rs b/src/error.rs
index 9e6adc0..f9af594 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -28,6 +28,8 @@ pub enum Error {
     UnexpectedError,
     /// An unknown error returned by libnitrokey.
     UnknownError(i64),
+    /// An error caused by a Nitrokey model that is not supported by this crate.
+    UnsupportedModelError,
     /// An error occurred when interpreting a UTF-8 string.
     Utf8Error(str::Utf8Error),
 }
@@ -102,6 +104,7 @@ impl error::Error for Error {
             Error::RandError(ref err) => Some(err.as_ref()),
             Error::UnexpectedError => None,
             Error::UnknownError(_) => None,
+            Error::UnsupportedModelError => None,
             Error::Utf8Error(ref err) => Some(err),
         }
     }
@@ -118,6 +121,7 @@ impl fmt::Display for Error {
             Error::RandError(ref err) => write!(f, "RNG error: {}", err),
             Error::UnexpectedError => write!(f, "An unexpected error occurred"),
             Error::UnknownError(ref err) => write!(f, "Unknown error: {}", err),
+            Error::UnsupportedModelError => write!(f, "Unsupported Nitrokey model"),
             Error::Utf8Error(ref err) => write!(f, "UTF-8 error: {}", err),
         }
     }
diff --git a/src/lib.rs b/src/lib.rs
index 059792d..9efad91 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,6 +16,10 @@
 //! [`connect_model`][], [`connect_pro`][] or [`connect_storage`][] to connect to a specific
 //! device.
 //!
+//! To get a list of all connected Nitrokey devices, use the [`list_devices`][] function.  You can
+//! then connect to one of the connected devices using the [`connect_path`][] function of the
+//! `Manager` struct.
+//!
 //! You can call [`authenticate_user`][] or [`authenticate_admin`][] to get an authenticated device
 //! that can perform operations that require authentication.  You can use [`device`][] to go back
 //! to the unauthenticated device.
@@ -25,6 +29,15 @@
 //! passwords – [`get_hotp_code`][] and [`get_totp_code`][].  Depending on the stick configuration,
 //! these operations are available without authentication or with user authentication.
 //!
+//! # Background operations
+//!
+//! Some commands may start background operations.  During such an operation, every new command
+//! will cause a [`WrongCrc`][] error.  To check whether a background operation is currently
+//! running, use the [`get_operation_status`][] method.
+//!
+//! Background operations are only available on the Nitrokey Storage.  Currently,
+//! [`fill_sd_card`][] is the only command that triggers a background operation.
+//!
 //! # Examples
 //!
 //! Connect to any Nitrokey and print its serial number:
@@ -86,8 +99,12 @@
 //! [`take`]: fn.take.html
 //! [`connect`]: struct.Manager.html#method.connect
 //! [`connect_model`]: struct.Manager.html#method.connect_model
+//! [`connect_path`]: struct.Manager.html#method.connect_path
 //! [`connect_pro`]: struct.Manager.html#method.connect_pro
 //! [`connect_storage`]: struct.Manager.html#method.connect_storage
+//! [`fill_sd_card`]: struct.Storage.html#method.fill_sd_card
+//! [`get_operation_status`]: struct.Storage.html#method.get_operation_status
+//! [`list_devices`]: fn.list_devices.html
 //! [`manager`]: trait.Device.html#method.manager
 //! [`device`]: struct.User.html#method.device
 //! [`get_hotp_code`]: trait.GenerateOtp.html#method.get_hotp_code
@@ -95,6 +112,7 @@
 //! [`Admin`]: struct.Admin.html
 //! [`DeviceWrapper`]: enum.DeviceWrapper.html
 //! [`User`]: struct.User.html
+//! [`WrongCrc`]: enum.CommandError.html#variant.WrongCrc
 
 #![warn(missing_docs, rust_2018_compatibility, rust_2018_idioms, unused)]
 
@@ -109,8 +127,10 @@ mod otp;
 mod pws;
 mod util;
 
+use std::convert::TryInto as _;
 use std::fmt;
 use std::marker;
+use std::ptr::NonNull;
 use std::sync;
 
 use nitrokey_sys;
@@ -118,14 +138,16 @@ use nitrokey_sys;
 pub use crate::auth::{Admin, Authenticate, User};
 pub use crate::config::Config;
 pub use crate::device::{
-    Device, DeviceWrapper, Model, Pro, SdCardData, Storage, StorageProductionInfo, StorageStatus,
-    VolumeMode, VolumeStatus,
+    Device, DeviceInfo, DeviceWrapper, Model, OperationStatus, Pro, SdCardData, Status, Storage,
+    StorageProductionInfo, StorageStatus, VolumeMode, VolumeStatus,
 };
 pub use crate::error::{CommandError, CommunicationError, Error, LibraryError};
 pub use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData};
 pub use crate::pws::{GetPasswordSafe, PasswordSafe, SLOT_COUNT};
 pub use crate::util::LogLevel;
 
+use crate::util::{get_cstring, get_last_result};
+
 /// The default admin PIN for all Nitrokey devices.
 pub const DEFAULT_ADMIN_PIN: &str = "12345678";
 /// The default user PIN for all Nitrokey devices.
@@ -235,6 +257,7 @@ impl Manager {
     /// # Errors
     ///
     /// - [`NotConnected`][] if no Nitrokey device is connected
+    /// - [`UnsupportedModelError`][] if the Nitrokey device is not supported by this crate
     ///
     /// # Example
     ///
@@ -252,6 +275,7 @@ impl Manager {
     /// ```
     ///
     /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
+    /// [`UnsupportedModelError`]: enum.Error.html#variant.UnsupportedModelError
     pub fn connect(&mut self) -> Result<DeviceWrapper<'_>, Error> {
         if unsafe { nitrokey_sys::NK_login_auto() } == 1 {
             device::get_connected_device(self)
@@ -290,6 +314,49 @@ impl Manager {
         }
     }
 
+    /// Connects to a Nitrokey device at the given USB path.
+    ///
+    /// To get a list of all connected Nitrokey devices, use the [`list_devices`][] function.  The
+    /// [`DeviceInfo`][] structs returned by that function contain the USB path in the `path`
+    /// field.
+    ///
+    /// # Errors
+    ///
+    /// - [`InvalidString`][] if the USB path contains a null byte
+    /// - [`NotConnected`][] if no Nitrokey device can be found at the given USB path
+    /// - [`UnsupportedModelError`][] if the model of the Nitrokey device at the given USB path is
+    ///   not supported by this crate
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use nitrokey::DeviceWrapper;
+    ///
+    /// fn use_device(device: DeviceWrapper) {}
+    ///
+    /// let mut manager = nitrokey::take()?;
+    /// let devices = nitrokey::list_devices()?;
+    /// for device in devices {
+    ///     let device = manager.connect_path(device.path)?;
+    ///     use_device(device);
+    /// }
+    /// # Ok::<(), nitrokey::Error>(())
+    /// ```
+    ///
+    /// [`list_devices`]: fn.list_devices.html
+    /// [`DeviceInfo`]: struct.DeviceInfo.html
+    /// [`InvalidString`]: enum.LibraryError.html#variant.InvalidString
+    /// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
+    /// [`UnsupportedModelError`]: enum.Error.html#variant.UnsupportedModelError
+    pub fn connect_path<S: Into<Vec<u8>>>(&mut self, path: S) -> Result<DeviceWrapper<'_>, Error> {
+        let path = get_cstring(path)?;
+        if unsafe { nitrokey_sys::NK_connect_with_path(path.as_ptr()) } == 1 {
+            device::get_connected_device(self)
+        } else {
+            Err(CommunicationError::NotConnected.into())
+        }
+    }
+
     /// Connects to a Nitrokey Pro.
     ///
     /// # Errors
@@ -414,6 +481,71 @@ pub fn force_take() -> Result<sync::MutexGuard<'static, Manager>, Error> {
     }
 }
 
+/// List all connected Nitrokey devices.
+///
+/// This functions returns a vector with [`DeviceInfo`][] structs that contain information about
+/// all connected Nitrokey devices.  It will even list unsupported models, although you cannot
+/// connect to them.  To connect to a supported model, call the [`connect_path`][] function.
+///
+/// # Errors
+///
+/// - [`NotConnected`][] if a Nitrokey device has been disconnected during enumeration
+/// - [`Utf8Error`][] if the USB path or the serial number returned by libnitrokey are invalid
+///   UTF-8 strings
+///
+/// # Example
+///
+/// ```
+/// let devices = nitrokey::list_devices()?;
+/// if devices.is_empty() {
+///     println!("No connected Nitrokey devices found.");
+/// } else {
+///     println!("model\tpath\tserial number");
+///     for device in devices {
+///         match device.model {
+///             Some(model) => print!("{}", model),
+///             None => print!("unsupported"),
+///         }
+///         print!("\t{}\t", device.path);
+///         match device.serial_number {
+///             Some(serial_number) => println!("{}", serial_number),
+///             None => println!("unknown"),
+///         }
+///     }
+/// }
+/// # Ok::<(), nitrokey::Error>(())
+/// ```
+///
+/// [`connect_path`]: struct.Manager.html#fn.connect_path
+/// [`DeviceInfo`]: struct.DeviceInfo.html
+/// [`NotConnected`]: enum.CommunicationError.html#variant.NotConnected
+/// [`Utf8Error`]: enum.Error.html#variant.Utf8Error
+pub fn list_devices() -> Result<Vec<DeviceInfo>, Error> {
+    let ptr = NonNull::new(unsafe { nitrokey_sys::NK_list_devices() });
+    match ptr {
+        Some(mut ptr) => {
+            let mut vec: Vec<DeviceInfo> = Vec::new();
+            push_device_info(&mut vec, unsafe { ptr.as_ref() })?;
+            unsafe {
+                nitrokey_sys::NK_free_device_info(ptr.as_mut());
+            }
+            Ok(vec)
+        }
+        None => get_last_result().map(|_| Vec::new()),
+    }
+}
+
+fn push_device_info(
+    vec: &mut Vec<DeviceInfo>,
+    info: &nitrokey_sys::NK_device_info,
+) -> Result<(), Error> {
+    vec.push(info.try_into()?);
+    if let Some(ptr) = NonNull::new(info.next) {
+        push_device_info(vec, unsafe { ptr.as_ref() })?;
+    }
+    Ok(())
+}
+
 /// Enables or disables debug output.  Calling this method with `true` is equivalent to setting the
 /// log level to `Debug`; calling it with `false` is equivalent to the log level `Error` (see
 /// [`set_log_level`][]).