Merge branch 'get_config' into next

This patch series changes the Device::get_config implementation to use
libnitrokey’s NK_get_status instead of NK_read_config.  This does
results in the same command being sent to the Nitrokey device, but
avoids a new[]/free mismatch and makes the parsing more robust.

3 files changed, 22 insertions, 25 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f5bb7cb..c94e170 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ SPDX-License-Identifier: CC0-1.0
     _>` to `Result<u32, _>`.
   - Change the type of the field `DeviceInfo.serial_number` from
     `Option<String>` to `Option<u32>`.
+- Use `NK_get_status` instead of `NK_read_config` to implement the
+  `Device::get_config` function.
 
 # v0.5.2 (2020-01-28)
 - Use `CString` to store the temporary password instead of `Vec<u8>`.
diff --git a/src/config.rs b/src/config.rs
index cb678d7..120a51b 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -83,13 +83,13 @@ impl convert::TryFrom<Config> for RawConfig {
     }
 }
 
-impl From<[u8; 5]> for RawConfig {
-    fn from(data: [u8; 5]) -> Self {
-        RawConfig {
-            numlock: data[0],
-            capslock: data[1],
-            scrollock: data[2],
-            user_password: data[3] != 0,
+impl From<&nitrokey_sys::NK_status> for RawConfig {
+    fn from(status: &nitrokey_sys::NK_status) -> Self {
+        Self {
+            numlock: status.config_numlock,
+            capslock: status.config_capslock,
+            scrollock: status.config_scrolllock,
+            user_password: status.otp_user_password,
         }
     }
 }
diff --git a/src/device/mod.rs b/src/device/mod.rs
index a25ad1b..e9ca0dc 100644
--- a/src/device/mod.rs
+++ b/src/device/mod.rs
@@ -9,7 +9,6 @@ use std::convert::{TryFrom, TryInto};
 use std::ffi;
 use std::fmt;
 
-use libc;
 use nitrokey_sys;
 
 use crate::auth::Authenticate;
@@ -18,8 +17,7 @@ use crate::error::{CommunicationError, Error};
 use crate::otp::GenerateOtp;
 use crate::pws::GetPasswordSafe;
 use crate::util::{
-    get_command_result, get_cstring, get_last_error, owned_str_from_ptr, result_from_string,
-    result_or_error,
+    get_command_result, get_cstring, owned_str_from_ptr, result_from_string, result_or_error,
 };
 
 pub use pro::Pro;
@@ -191,13 +189,7 @@ impl From<nitrokey_sys::NK_status> for Status {
                 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(),
+            config: RawConfig::from(&status).into(),
         }
     }
 }
@@ -392,14 +384,17 @@ pub trait Device<'a>: Authenticate<'a> + GetPasswordSafe<'a> + GenerateOtp + fmt
     /// # }
     /// ```
     fn get_config(&self) -> Result<Config, Error> {
-        let config_ptr = unsafe { nitrokey_sys::NK_read_config() };
-        if config_ptr.is_null() {
-            return Err(get_last_error());
-        }
-        let config_array_ptr = config_ptr as *const [u8; 5];
-        let raw_config = unsafe { RawConfig::from(*config_array_ptr) };
-        unsafe { libc::free(config_ptr as *mut libc::c_void) };
-        Ok(raw_config.into())
+        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(RawConfig::from(&raw_status).into())
     }
 
     /// Changes the administrator PIN.