Add --usb-path option to select device

This patch adds the --usb-path option as an additional way to filter the
Nitrokey device to connect to.  While the serial number is a better
identifier in theory, the Nitrokey Storage devices do not send their
serial number in the USB device descriptor.  Having the --usb-path
options allows users to select one of multiple Nitrokey Storage devices.

While we could directly call the nitrokey::Manager::connect_path
function with the specified path, we integrate the --usb-path option
into the existing find_device function for consistent error messages and
to avoid having to duplicate the --model and --serial-number checks.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/config.rs b/src/config.rs
index 6f0cd17..8e7eefb 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -31,6 +31,8 @@ pub struct Config {
   #[merge(strategy = merge::vec::overwrite_empty)]
   #[serde(default, deserialize_with = "deserialize_serial_number_vec")]
   pub serial_numbers: Vec<nitrokey::SerialNumber>,
+  /// The USB path of the device to connect to.
+  pub usb_path: Option<String>,
   /// Whether to bypass the cache for all secrets or not.
   #[merge(strategy = merge::bool::overwrite_false)]
   #[serde(default)]
@@ -74,6 +76,9 @@ impl Config {
       // TODO: Don't clone.
       self.serial_numbers = args.serial_numbers.clone();
     }
+    if args.usb_path.is_some() {
+      self.usb_path = args.usb_path.clone();
+    }
     if args.no_cache {
       self.no_cache = true;
     }