Honor context provided Admin & User PIN in pin commands

The second source of interactivity comes from the pin set and pin
unblock commands, which also inquire with the pinentry module to ask the
user for a PIN.
This change adjusts the two commands to honor the PINs as available in
the command execution context. It also updates the documentation
to reflect the availability of the newly introduced and honored
environment variables NITROCLI_ADMIN_PIN & NITROCLI_USER_PIN as well as
NITROCLI_NEW_ADMIN_PIN & NITROCLI_NEW_USER_PIN.

1 files changed, 39 insertions, 3 deletions

diff --git a/nitrocli/src/commands.rs b/nitrocli/src/commands.rs
index 6316c92..f8765cc 100644
--- a/nitrocli/src/commands.rs
+++ b/nitrocli/src/commands.rs
@@ -610,7 +610,7 @@ fn check_pin(pin_type: pinentry::PinType, pin: &str) -> Result<()> {
   }
 }
 
-fn choose_pin(pin_type: pinentry::PinType) -> Result<String> {
+fn choose_pin_with_pinentry(pin_type: pinentry::PinType) -> Result<String> {
   pinentry::clear_pin(pin_type)?;
   let new_pin = pinentry::inquire_pin(pin_type, pinentry::Mode::Choose, None)?;
   pinentry::clear_pin(pin_type)?;
@@ -626,10 +626,46 @@ fn choose_pin(pin_type: pinentry::PinType) -> Result<String> {
   }
 }
 
+/// Choose a PIN of the given type.
+///
+/// If the user has set the respective environment variable for the
+/// given PIN type, it will be used.
+fn choose_pin(
+  ctx: &mut args::ExecCtx<'_>,
+  pin_type: pinentry::PinType,
+  new: bool,
+) -> Result<String> {
+  let new_pin = match pin_type {
+    pinentry::PinType::Admin => {
+      if new {
+        &ctx.new_admin_pin
+      } else {
+        &ctx.admin_pin
+      }
+    }
+    pinentry::PinType::User => {
+      if new {
+        &ctx.new_user_pin
+      } else {
+        &ctx.user_pin
+      }
+    }
+  };
+
+  if let Some(new_pin) = new_pin {
+    new_pin
+      .to_str()
+      .ok_or_else(|| Error::Error("Failed to read PIN: invalid Unicode data found".into()))
+      .map(ToOwned::to_owned)
+  } else {
+    choose_pin_with_pinentry(pin_type)
+  }
+}
+
 /// Change a PIN.
 pub fn pin_set(ctx: &mut args::ExecCtx<'_>, pin_type: pinentry::PinType) -> Result<()> {
   let device = get_device(ctx)?;
-  let new_pin = choose_pin(pin_type)?;
+  let new_pin = choose_pin(ctx, pin_type, true)?;
   try_with_pin(
     ctx,
     pin_type,
@@ -644,7 +680,7 @@ pub fn pin_set(ctx: &mut args::ExecCtx<'_>, pin_type: pinentry::PinType) -> Resu
 /// Unblock and reset the user PIN.
 pub fn pin_unblock(ctx: &mut args::ExecCtx<'_>) -> Result<()> {
   let device = get_device(ctx)?;
-  let user_pin = choose_pin(pinentry::PinType::User)?;
+  let user_pin = choose_pin(ctx, pinentry::PinType::User, false)?;
   try_with_pin(
     ctx,
     pinentry::PinType::Admin,