Implement Display for errors

Author: Santiago Cingolani

heimlig/Cargo.lock

@@ -19,6 +19,7 @@ chacha20poly1305 = { version = "0.10.1", default-features = false }
 cmac = { version = "0.7.2", default-features = false }
 critical-section = { version = "1.1.2", default-features = false }
 dbl = { version = "0.3.2", default-features = false }
+displaydoc = { version = "0.2.4", default-features = false }
 ecdsa = { version = "0.16.8", default-features = false }
 ed25519-dalek = { version = "2.1.1", default-features = false, features = ["zeroize"] }
 elliptic-curve = { version = "0.13.5", default-features = false }
@@ -47,4 +48,4 @@ ed25519-dalek = { version = "2.1.1", default-features = false, features = ["zero
 cbindgen = { version = "0.26.0", default-features = false }
 
 [lints.clippy]
-undocumented_unsafe_blocks = "warn"
+undocumented_unsafe_blocks = "warn"

heimlig/Cargo.toml

@@ -1,7 +1,9 @@
+use displaydoc::Display;
+
 use crate::hsm::keystore;
 use crate::hsm::keystore::{Curve, KeyId};
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Display)]
 pub enum Error {
     /// No worker found for received request type.
     NoWorkerForRequest,
@@ -13,11 +15,11 @@ pub enum Error {
     NoKeyStore,
     /// Failed to send through channel.
     Send,
-    /// Futures Stream was terminated
+    /// Futures Stream was terminated.
     StreamTerminated,
-    /// A cryptographic error occurred.
+    /// A cryptographic error occurred: {0}
     Crypto(crate::crypto::Error),
-    /// A key store error occurred.
+    /// A key store error occurred: {0}
     KeyStore(keystore::Error),
 }
 

heimlig/src/common/jobs.rs

@@ -1,3 +1,5 @@
+use displaydoc::Display;
+
 pub mod aes;
 pub mod chacha20poly1305;
 pub mod ecc;
@@ -10,7 +12,7 @@ pub mod rng;
 pub mod x25519;
 
 /// Common errors.
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Display)]
 pub enum Error {
     /// Error during encryption.
     Encrypt,

heimlig/src/crypto/mod.rs

@@ -4,13 +4,14 @@ use crate::hsm::keystore;
 use core::future::poll_fn;
 use core::ops::DerefMut;
 use core::pin::Pin;
+use displaydoc::Display;
 use embassy_futures::select::select_slice;
 use embassy_sync::blocking_mutex::raw::RawMutex;
 use embassy_sync::mutex::Mutex;
 use futures::{FutureExt, Sink, SinkExt, Stream, StreamExt};
 use heapless::Vec;
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Display)]
 pub enum Error {
     /// Error sending message through queue
     Send,
@@ -26,24 +27,24 @@ pub enum Error {
     ChannelForRequestExists,
     /// Maximum number of request types for a single worker exceeded
     TooManyRequestTypes,
-    /// An internal error occurred
+    /// An internal error occurred: {0}
     Internal(InternalError),
 }
 
 /// Internal errors that a client should not be able to trigger.
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Display)]
 pub enum InternalError {
-    // The internal client ID was invalid for the internal list of client channels.
+    /// The internal client ID ({0:?}) was invalid for the internal list of client channels.
     InvalidClientId(ClientId),
-    // The internal worker ID was invalid for the internal list of worker channels.
+    /// The internal worker ID ({0:?}) was invalid for the internal list of worker channels.
     InvalidWorkerId(WorkerId),
-    /// An empty client request queue was encountered even though a previous check made sure that it was non-empty.
+    /// An empty client ({0:?}) request queue was encountered even though a previous check made sure that it was non-empty.
     EmptyClientRequestQueue(ClientId),
-    /// An empty worker response queue was encountered even though a previous check made sure that it was non-empty.
+    /// An empty worker ({0:?}) response queue was encountered even though a previous check made sure that it was non-empty.
     EmptyWorkerResponseQueue(WorkerId),
-    /// The core encountered a request type it cannot handle
+    /// The core encountered a request ({0:?}) type it cannot handle.
     UnexpectedCoreRequest(RequestType),
-    // The client ID of the response that was determined to be processed next did not match the one in the response queue.
+    /// The client ID of the response that was determined to be processed next ({0:?}) did not match the one in the response queue ({1:?}).
     ClientIdMismatch(ClientId, ClientId),
 }
 

heimlig/src/hsm/core.rs

@@ -1,14 +1,16 @@
+use displaydoc::Display;
+
 /// Identifier to reference HSM keys
 #[derive(Clone, Copy, Debug, Default, Eq, PartialEq, Ord, PartialOrd)]
 pub struct KeyId(pub u32);
 
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Display)]
 pub enum Error {
     /// The operation is not permitted
     NotAllowed,
     /// The requested key was not found.
     KeyNotFound,
-    /// The operation attempted to overwrite an existing key when it was not permitted
+    /// The operation attempted to overwrite an existing key when it was not permitted.
     KeyAlreadyExists,
     /// The key store cannot handle the number of requested keys.
     KeyStoreTooSmall,