Add the fill_sd_card function to Storage

This patch adds support for libnitrokey’s
NK_fill_SD_card_with_random_data function.  It is executed by the
fill_sd_card function of the Storage struct.  We also add a new test
case that is set to ignore because it takes between 30 and 60 minutes to
run.

1 files changed, 51 insertions, 2 deletions

diff --git a/src/device/storage.rs b/src/device/storage.rs
index 8d45763..deb2844 100644
--- a/src/device/storage.rs
+++ b/src/device/storage.rs
@@ -8,7 +8,7 @@ use std::ops;
 use nitrokey_sys;
 
 use crate::device::{Device, FirmwareVersion, Model, Status};
-use crate::error::Error;
+use crate::error::{CommandError, Error};
 use crate::otp::GenerateOtp;
 use crate::util::{get_command_result, get_cstring, get_last_error};
 
@@ -700,7 +700,9 @@ impl<'a> Storage<'a> {
     /// 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.
+    /// 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 {
@@ -713,6 +715,53 @@ impl<'a> Storage<'a> {
         }
     }
 
+    /// 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