Add the --progress option to the fill command

The fill command starts a background operation on a Nitrokey Storage
device that fills the SD card with random data.  This patch adds a new
option, --progress, to the fill command that checks if a fill operation
is already running on the device and shows its progress.

5 files changed, 37 insertions, 13 deletions

diff --git a/doc/nitrocli.1 b/doc/nitrocli.1
index fd04d45..c6d27be 100644
--- a/doc/nitrocli.1
+++ b/doc/nitrocli.1
@@ -137,7 +137,7 @@ open.
 \fBnitrocli hidden close
 Close a hidden volume.
 .TP
-\fBnitrocli fill\fR
+\fBnitrocli fill \fR[\fB\-a\fR|\fB\-\-attach\fR
 Fills the SD card with random data, overwriting all existing data.
 This operation takes about one hour to finish for a 16 GiB SD card.
 It cannot be canceled, even if the \fBnitrocli\fR process is terminated before
@@ -147,6 +147,11 @@ This command requires the admin PIN.
 To avoid accidental calls of this command, the user has to enter the PIN even
 if it has been cached.
 
+If the \fB\-\-attach\fR option is set, this command will not start a new fill
+operation.
+Instead it checks whether a fill operation is currently running on the device
+and shows its progress.
+
 .SS One-time passwords
 The Nitrokey Pro and the Nitrokey Storage support the generation of one-time
 passwords using the HOTP algorithm according to RFC 4226 or the TOTP algorithm
diff --git a/doc/nitrocli.1.pdf b/doc/nitrocli.1.pdf
index d04fe02..6fd3406 100644
--- a/doc/nitrocli.1.pdf
+++ b/doc/nitrocli.1.pdf
diff --git a/src/args.rs b/src/args.rs
index 4947825..8af38ca 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -80,7 +80,7 @@ Command! {
     /// Interacts with the device's encrypted volume
     Encrypted(EncryptedArgs) => |ctx, args: EncryptedArgs| args.subcmd.execute(ctx),
     /// Fills the SD card with random data
-    Fill => crate::commands::fill,
+    Fill(FillArgs) => |ctx, args: FillArgs| crate::commands::fill(ctx, args.attach),
     /// Interacts with the device's hidden volume
     Hidden(HiddenArgs) => |ctx, args: HiddenArgs| args.subcmd.execute(ctx),
     /// Lists the attached Nitrokey devices
@@ -190,6 +190,14 @@ Command! {EncryptedCommand, [
 ]}
 
 #[derive(Debug, PartialEq, structopt::StructOpt)]
+pub struct FillArgs {
+  /// Checks if a fill operation is already running and show its progress instead of starting a new
+  /// operation.
+  #[structopt(short, long)]
+  attach: bool,
+}
+
+#[derive(Debug, PartialEq, structopt::StructOpt)]
 pub struct HiddenArgs {
   #[structopt(subcommand)]
   subcmd: HiddenCommand,
diff --git a/src/commands.rs b/src/commands.rs
index 7b48bb2..51ac32f 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -471,19 +471,30 @@ pub fn list(ctx: &mut Context<'_>, no_connect: bool) -> anyhow::Result<()> {
 }
 
 /// Fill the SD card with random data
-pub fn fill(ctx: &mut Context<'_>) -> anyhow::Result<()> {
+pub fn fill(ctx: &mut Context<'_>, attach: bool) -> anyhow::Result<()> {
   with_storage_device(ctx, |ctx, mut device| {
-    let pin_entry = pinentry::PinEntry::from(args::PinType::Admin, &device)?;
+    let mut initial_progress = 0;
+    if attach {
+      let status = device
+        .get_operation_status()
+        .context("Failed to query operation status")?;
+      match status {
+        nitrokey::OperationStatus::Ongoing(progress) => initial_progress = progress,
+        nitrokey::OperationStatus::Idle => anyhow::bail!("No fill operation in progress"),
+      }
+    } else {
+      let pin_entry = pinentry::PinEntry::from(args::PinType::Admin, &device)?;
 
-    // Similar to reset, we want the user to re-enter the admin PIN even if is cached to avoid
-    // accidental data loss.
-    pinentry::clear(&pin_entry).context("Failed to clear cached secret")?;
+      // Similar to reset, we want the user to re-enter the admin PIN
+      // even if is cached to avoid accidental data loss.
+      pinentry::clear(&pin_entry).context("Failed to clear cached secret")?;
 
-    try_with_pin(ctx, &pin_entry, |pin| {
-      device.fill_sd_card(&pin).context("Failed to fill SD card")
-    })?;
+      try_with_pin(ctx, &pin_entry, |pin| {
+        device.fill_sd_card(&pin).context("Failed to fill SD card")
+      })?;
+    }
 
-    let mut progress_bar = output::ProgressBar::new();
+    let mut progress_bar = output::ProgressBar::new(initial_progress);
     progress_bar.draw(ctx)?;
 
     while !progress_bar.is_finished() {
diff --git a/src/output.rs b/src/output.rs
index bd6c03c..1811cc3 100644
--- a/src/output.rs
+++ b/src/output.rs
@@ -26,10 +26,10 @@ pub struct ProgressBar {
 
 impl ProgressBar {
   /// Creates a new empty progress bar.
-  pub fn new() -> ProgressBar {
+  pub fn new(progress: u8) -> ProgressBar {
     ProgressBar {
       redraw: true,
-      progress: 0,
+      progress,
       toggle: false,
       finished: false,
     }