Merge branch 'connect_path' into next

This patch series adds the list_devices function that returns a list of
available Nitrokey devices and the Manager::connect_path function that
connects to one of the available devices.

1 files changed, 131 insertions, 16 deletions

diff --git a/src/device/mod.rs b/src/device/mod.rs
index 5e15f08..e015886 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;
@@ -16,7 +19,8 @@ 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;
@@ -43,6 +47,97 @@ 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 {
@@ -428,12 +523,8 @@ 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 +540,40 @@ 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")
+        );
+    }
 }