refactor (hardware wallet) : reduce the number of threads (#9644)

* refactor(hardware-wallet) - use only one thread

This changes parity to use one thread instead of two to subscribe USB
events via the hardware-wallets.

* Fix logs and tests

* fix(grumbles) : formatting and spelling nits

* Update hw/src/lib.rs

Co-Authored-By: niklasad1 <niklasadolfsson1@gmail.com>

* Update hw/src/lib.rs

Co-Authored-By: niklasad1 <niklasadolfsson1@gmail.com>

* Update hw/src/ledger.rs

Co-Authored-By: niklasad1 <niklasadolfsson1@gmail.com>

* fix(grumbles): clarify docs and use constants

* Clarify bad explaination of `run-to-completion`
* Replace magic numbers with constants

accounts/hw/src/lib.rs

@@ -34,15 +34,18 @@ extern crate trezor_sys;
 mod ledger;
 mod trezor;
 
-use std::sync::{Arc, atomic, atomic::AtomicBool};
+use std::sync::{Arc, atomic, atomic::AtomicBool, Weak};
 use std::{fmt, time::Duration};
+use std::thread;
 
 use ethereum_types::U256;
 use ethkey::{Address, Signature};
 use parking_lot::Mutex;
 
-const USB_DEVICE_CLASS_DEVICE: u8 = 0;
+const HID_GLOBAL_USAGE_PAGE: u16 = 0xFF00;
-const POLLING_DURATION: Duration = Duration::from_millis(500);
+const HID_USB_DEVICE_CLASS: u8 = 0;
+const MAX_POLLING_DURATION: Duration = Duration::from_millis(500);
+const USB_EVENT_POLLING_INTERVAL: Duration = Duration::from_millis(500);
 
 /// `HardwareWallet` device
 #[derive(Debug)]
@@ -189,7 +192,7 @@ impl From<libusb::Error> for Error {
 }
 
 /// Specifies the direction of the `HardwareWallet` i.e, whether it arrived or left
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, PartialEq)]
 pub enum DeviceDirection {
 	/// Device arrived
 	Arrived,
@@ -218,13 +221,47 @@ impl HardwareWalletManager {
 	pub fn new() -> Result<Self, Error> {
 		let exiting = Arc::new(AtomicBool::new(false));
 		let hidapi = Arc::new(Mutex::new(hidapi::HidApi::new().map_err(|e| Error::Hid(e.to_string().clone()))?));
-		let ledger = ledger::Manager::new(hidapi.clone(), exiting.clone())?;
+		let ledger = ledger::Manager::new(hidapi.clone());
-		let trezor = trezor::Manager::new(hidapi.clone(), exiting.clone())?;
+		let trezor = trezor::Manager::new(hidapi.clone());
+		let usb_context = Arc::new(libusb::Context::new()?);
+
+		let l = ledger.clone();
+		let t = trezor.clone();
+		let exit = exiting.clone();
+
+		// Subscribe to all vendor IDs (VIDs) and product IDs (PIDs)
+		// This means that the `HardwareWalletManager` is responsible to validate the detected device
+		usb_context.register_callback(
+			None, None, Some(HID_USB_DEVICE_CLASS),
+			Box::new(EventHandler::new(
+				Arc::downgrade(&ledger),
+				Arc::downgrade(&trezor)
+			))
+		)?;
+
+		// Hardware event subscriber thread
+		thread::Builder::new()
+			.name("hw_wallet_manager".to_string())
+			.spawn(move || {
+				if let Err(e) = l.update_devices(DeviceDirection::Arrived) {
+					debug!(target: "hw", "Ledger couldn't connect at startup, error: {}", e);
+				}
+				if let Err(e) = t.update_devices(DeviceDirection::Arrived) {
+					debug!(target: "hw", "Trezor couldn't connect at startup, error: {}", e);
+				}
+
+				while !exit.load(atomic::Ordering::Acquire) {
+					if let Err(e) = usb_context.handle_events(Some(USB_EVENT_POLLING_INTERVAL)) {
+						debug!(target: "hw", "HardwareWalletManager event handler error: {}", e);
+					}
+				}
+			})
+			.ok();
 
 		Ok(Self {
 			exiting,
-			ledger,
 			trezor,
+			ledger,
 		})
 	}
 
@@ -292,10 +329,74 @@ impl HardwareWalletManager {
 
 impl Drop for HardwareWalletManager {
 	fn drop(&mut self) {
-		// Indicate to the USB Hotplug handlers that they
+		// Indicate to the USB Hotplug handler that it
-		// shall terminate but don't wait for them to terminate.
+		// shall terminate but don't wait for it to terminate.
-		// If they don't terminate for some reason USB Hotplug events will be handled
+		// If it doesn't terminate for some reason USB Hotplug events will be handled
 		// even if the HardwareWalletManger has been dropped
 		self.exiting.store(true, atomic::Ordering::Release);
 	}
 }
+
+/// Hardware wallet event handler
+///
+/// Note, that this runs to completion and race-conditions can't occur but it can
+/// stop other events for being processed with an infinite loop or similar
+struct EventHandler {
+	ledger: Weak<ledger::Manager>,
+	trezor: Weak<trezor::Manager>,
+}
+
+impl EventHandler {
+	/// Trezor event handler constructor
+	pub fn new(ledger: Weak<ledger::Manager>, trezor: Weak<trezor::Manager>) -> Self {
+		Self { ledger, trezor }
+	}
+
+	fn extract_device_info(device: &libusb::Device) -> Result<(u16, u16), Error> {
+		let desc = device.device_descriptor()?;
+		Ok((desc.vendor_id(), desc.product_id()))
+	}
+}
+
+impl libusb::Hotplug for EventHandler {
+	fn device_arrived(&mut self, device: libusb::Device) {
+		// Upgrade reference to an Arc
+		if let (Some(ledger), Some(trezor)) = (self.ledger.upgrade(), self.trezor.upgrade()) {
+			// Version ID and Product ID are available
+			if let Ok((vid, pid)) = Self::extract_device_info(&device) {
+				if trezor::is_valid_trezor(vid, pid) {
+					if !trezor::try_connect_polling(&trezor, &MAX_POLLING_DURATION, DeviceDirection::Arrived) {
+						trace!(target: "hw", "Trezor device was detected but connection failed");
+					}
+				} else if ledger::is_valid_ledger(vid, pid) {
+					if !ledger::try_connect_polling(&ledger, &MAX_POLLING_DURATION, DeviceDirection::Arrived) {
+						trace!(target: "hw", "Ledger device was detected but connection failed");
+					}
+				}
+			}
+		}
+	}
+
+	fn device_left(&mut self, device: libusb::Device) {
+		// Upgrade reference to an Arc
+		if let (Some(ledger), Some(trezor)) = (self.ledger.upgrade(), self.trezor.upgrade()) {
+			// Version ID and Product ID are available
+			if let Ok((vid, pid)) = Self::extract_device_info(&device) {
+				if trezor::is_valid_trezor(vid, pid) {
+					if !trezor::try_connect_polling(&trezor, &MAX_POLLING_DURATION, DeviceDirection::Left) {
+						trace!(target: "hw", "Trezor device was detected but disconnection failed");
+					}
+				} else if ledger::is_valid_ledger(vid, pid) {
+					if !ledger::try_connect_polling(&ledger, &MAX_POLLING_DURATION, DeviceDirection::Left) {
+						trace!(target: "hw", "Ledger device was detected but disconnection failed");
+					}
+				}
+			}
+		}
+	}
+}
+
+/// Helper to determine if a device is a valid HID
+pub fn is_valid_hid_device(usage_page: u16, interface_number: i32) -> bool {
+	usage_page == HID_GLOBAL_USAGE_PAGE || interface_number == HID_USB_DEVICE_CLASS as i32
+}

accounts/hw/src/trezor.rs

@@ -20,9 +20,9 @@
 //! for protocol details.
 
 use std::cmp::{min, max};
-use std::sync::{atomic, atomic::AtomicBool, Arc, Weak};
+use std::sync::Arc;
 use std::time::{Duration, Instant};
-use std::{fmt, thread};
+use std::fmt;
 
 use ethereum_types::{U256, H256, Address};
 use ethkey::Signature;
@@ -30,7 +30,7 @@ use hidapi;
 use libusb;
 use parking_lot::{Mutex, RwLock};
 use protobuf::{self, Message, ProtobufEnum};
-use super::{DeviceDirection, WalletInfo, TransactionInfo, KeyPath, Wallet, Device, USB_DEVICE_CLASS_DEVICE, POLLING_DURATION};
+use super::{DeviceDirection, WalletInfo, TransactionInfo, KeyPath, Wallet, Device, is_valid_hid_device};
 use trezor_sys::messages::{EthereumAddress, PinMatrixAck, MessageType, EthereumTxRequest, EthereumSignTx, EthereumGetAddress, EthereumTxAck, ButtonAck};
 
 /// Trezor v1 vendor ID
@@ -48,6 +48,8 @@ pub enum Error {
 	Protocol(&'static str),
 	/// Hidapi error.
 	Usb(hidapi::HidError),
+	/// Libusb error
+	LibUsb(libusb::Error),
 	/// Device with request key is not available.
 	KeyNotFound,
 	/// Signing has been cancelled by user.
@@ -62,6 +64,8 @@ pub enum Error {
 	NoDeviceArrived,
 	/// No device left
 	NoDeviceLeft,
+	/// Invalid PID or VID
+	InvalidDevice,
 }
 
 impl fmt::Display for Error {
@@ -69,6 +73,7 @@ impl fmt::Display for Error {
 		match *self {
 			Error::Protocol(ref s) => write!(f, "Trezor protocol error: {}", s),
 			Error::Usb(ref e) => write!(f, "USB communication error: {}", e),
+			Error::LibUsb(ref e) => write!(f, "LibUSB communication error: {}", e),
 			Error::KeyNotFound => write!(f, "Key not found"),
 			Error::UserCancel => write!(f, "Operation has been cancelled"),
 			Error::BadMessageType => write!(f, "Bad Message Type in RPC call"),
@@ -76,6 +81,7 @@ impl fmt::Display for Error {
 			Error::NoSigningMessage=> write!(f, "Signing messages are not supported by Trezor"),
 			Error::NoDeviceArrived => write!(f, "No device arrived"),
 			Error::NoDeviceLeft => write!(f, "No device left"),
+			Error::InvalidDevice => write!(f, "Device with non-supported product ID or vendor ID was detected"),
 		}
 	}
 }
@@ -86,6 +92,12 @@ impl From<hidapi::HidError> for Error {
 	}
 }
 
+impl From<libusb::Error> for Error {
+	fn from(err: libusb::Error) -> Self {
+		Error::LibUsb(err)
+	}
+}
+
 impl From<protobuf::ProtobufError> for Error {
 	fn from(_: protobuf::ProtobufError) -> Self {
 		Error::Protocol(&"Could not read response from Trezor Device")
@@ -93,7 +105,7 @@ impl From<protobuf::ProtobufError> for Error {
 }
 
 /// Trezor device manager
-pub (crate) struct Manager {
+pub struct Manager {
 	usb: Arc<Mutex<hidapi::HidApi>>,
 	devices: RwLock<Vec<Device>>,
 	locked_devices: RwLock<Vec<String>>,
@@ -108,42 +120,13 @@ enum HidVersion {
 
 impl Manager {
 	/// Create a new instance.
-	pub fn new(hidapi: Arc<Mutex<hidapi::HidApi>>, exiting: Arc<AtomicBool>) -> Result<Arc<Self>, libusb::Error> {
+	pub fn new(usb: Arc<Mutex<hidapi::HidApi>>) -> Arc<Self> {
-		let manager = Arc::new(Self {
+		Arc::new(Self {
-			usb: hidapi,
+			usb,
 			devices: RwLock::new(Vec::new()),
 			locked_devices: RwLock::new(Vec::new()),
 			key_path: RwLock::new(KeyPath::Ethereum),
-		});
-
-		let usb_context = Arc::new(libusb::Context::new()?);
-		let m = manager.clone();
-
-		// Subscribe to TREZOR V1
-		// Note, this support only TREZOR V1 because TREZOR V2 has a different vendorID for some reason
-		// Also, we now only support one product as the second argument specifies
-		usb_context.register_callback(
-			Some(TREZOR_VID), Some(TREZOR_PIDS[0]), Some(USB_DEVICE_CLASS_DEVICE),
-			Box::new(EventHandler::new(Arc::downgrade(&manager))))?;
-
-		// Trezor event thread
-		thread::Builder::new()
-			.name("hw_wallet_trezor".to_string())
-			.spawn(move || {
-				if let Err(e) = m.update_devices(DeviceDirection::Arrived) {
-					debug!(target: "hw", "Trezor couldn't connect at startup, error: {}", e);
-				}
-				loop {
-					usb_context.handle_events(Some(Duration::from_millis(500)))
-						.unwrap_or_else(|e| debug!(target: "hw", "Trezor event handler error: {}", e));
-					if exiting.load(atomic::Ordering::Acquire) {
-						break;
-					}
-				}
 		})
-			.ok();
-
-		Ok(manager)
 	}
 
 	pub fn pin_matrix_ack(&self, device_path: &str, pin: &str) -> Result<bool, Error> {
@@ -153,7 +136,7 @@ impl Manager {
 			let t = MessageType::MessageType_PinMatrixAck;
 			let mut m = PinMatrixAck::new();
 			m.set_pin(pin.to_string());
-			self.send_device_message(&device, &t, &m)?;
+			self.send_device_message(&device, t, &m)?;
 			let (resp_type, _) = self.read_device_response(&device)?;
 			match resp_type {
 				// Getting an Address back means it's unlocked, this is undocumented behavior
@@ -178,7 +161,7 @@ impl Manager {
 		match resp_type {
 			MessageType::MessageType_Cancel => Err(Error::UserCancel),
 			MessageType::MessageType_ButtonRequest => {
-				self.send_device_message(handle, &MessageType::MessageType_ButtonAck, &ButtonAck::new())?;
+				self.send_device_message(handle, MessageType::MessageType_ButtonAck, &ButtonAck::new())?;
 				// Signing loop goes back to the top and reading blocks
 				// for up to 5 minutes waiting for response from the device
 				// if the user doesn't click any button within 5 minutes you
@@ -191,7 +174,7 @@ impl Manager {
 					let mut msg = EthereumTxAck::new();
 					let len = resp.get_data_length() as usize;
 					msg.set_data_chunk(data[..len].to_vec());
-					self.send_device_message(handle, &MessageType::MessageType_EthereumTxAck, &msg)?;
+					self.send_device_message(handle, MessageType::MessageType_EthereumTxAck, &msg)?;
 					self.signing_loop(handle, chain_id, &data[len..])
 				} else {
 					let v = resp.get_signature_v();
@@ -216,8 +199,8 @@ impl Manager {
 		}
 	}
 
-	fn send_device_message(&self, device: &hidapi::HidDevice, msg_type: &MessageType, msg: &Message) -> Result<usize, Error> {
+	fn send_device_message(&self, device: &hidapi::HidDevice, msg_type: MessageType, msg: &Message) -> Result<usize, Error> {
-		let msg_id = *msg_type as u16;
+		let msg_id = msg_type as u16;
 		let mut message = msg.write_to_bytes()?;
 		let msg_size = message.len();
 		let mut data = Vec::new();
@@ -316,7 +299,7 @@ impl <'a>Wallet<'a> for Manager {
 			message.set_chain_id(c_id as u32);
 		}
 
-		self.send_device_message(&handle, &msg_type, &message)?;
+		self.send_device_message(&handle, msg_type, &message)?;
 
 		self.signing_loop(&handle, &t_info.chain_id, &t_info.data[first_chunk_length..])
 	}
@@ -332,13 +315,9 @@ impl <'a>Wallet<'a> for Manager {
 		let num_prev_devices = self.devices.read().len();
 
 		let detected_devices = devices.iter()
-			.filter(|&d| {
+			.filter(|&d| is_valid_trezor(d.vendor_id, d.product_id) &&
-				let is_trezor = d.vendor_id == TREZOR_VID;
+					is_valid_hid_device(d.usage_page, d.interface_number)
-				let is_supported_product = TREZOR_PIDS.contains(&d.product_id);
+			)
-				let is_valid = d.usage_page == 0xFF00 || d.interface_number == 0;
-
-				is_trezor && is_supported_product && is_valid
-			})
 			.fold(Vec::new(), |mut v, d| {
 				match self.read_device(&usb, &d) {
 					Ok(info) => {
@@ -413,7 +392,7 @@ impl <'a>Wallet<'a> for Manager {
 			KeyPath::EthereumClassic => message.set_address_n(ETC_DERIVATION_PATH.to_vec()),
 		}
 		message.set_show_display(false);
-		self.send_device_message(&device, &typ, &message)?;
+		self.send_device_message(&device, typ, &message)?;
 
 		let (resp_type, bytes) = self.read_device_response(&device)?;
 		match resp_type {
@@ -432,8 +411,9 @@ impl <'a>Wallet<'a> for Manager {
 	}
 }
 
-// Try to connect to the device using polling in at most the time specified by the `timeout`
+
-fn try_connect_polling(trezor: &Manager, duration: &Duration, dir: DeviceDirection) -> bool {
+/// Poll the device in maximum `max_polling_duration` if it doesn't succeed
+pub fn try_connect_polling(trezor: &Manager, duration: &Duration, dir: DeviceDirection) -> bool {
 	let start_time = Instant::now();
 	while start_time.elapsed() <= *duration {
 		if let Ok(num_devices) = trezor.update_devices(dir) {
@@ -444,73 +424,43 @@ fn try_connect_polling(trezor: &Manager, duration: &Duration, dir: DeviceDirecti
 	false
 }
 
-/// Trezor event handler
+/// Check if the detected device is a Trezor device by checking both the product ID and the vendor ID
-/// A separate thread is handling incoming events
+pub fn is_valid_trezor(vid: u16, pid: u16) -> bool {
-///
+	vid == TREZOR_VID && TREZOR_PIDS.contains(&pid)
-/// Note, that this run to completion and race-conditions can't occur but this can
-/// therefore starve other events for being process with a spinlock or similar
-struct EventHandler {
-	trezor: Weak<Manager>,
 }
 
-impl EventHandler {
-	/// Trezor event handler constructor
-	pub fn new(trezor: Weak<Manager>) -> Self {
-		Self { trezor }
-	}
-}
 
-impl libusb::Hotplug for EventHandler {
-	fn device_arrived(&mut self, _device: libusb::Device) {
-		debug!(target: "hw", "Trezor V1 arrived");
-		if let Some(trezor) = self.trezor.upgrade() {
-			if try_connect_polling(&trezor, &POLLING_DURATION, DeviceDirection::Arrived) != true {
-				trace!(target: "hw", "No Trezor connected");
-			}
-		}
-	}
-
-	fn device_left(&mut self, _device: libusb::Device) {
-		debug!(target: "hw", "Trezor V1 left");
-		if let Some(trezor) = self.trezor.upgrade() {
-			if try_connect_polling(&trezor, &POLLING_DURATION, DeviceDirection::Left) != true {
-				trace!(target: "hw", "No Trezor disconnected");
-			}
-		}
-	}
-}
 
 #[test]
 #[ignore]
 /// This test can't be run without an actual trezor device connected
 /// (and unlocked) attached to the machine that's running the test
 fn test_signature() {
-	use ethereum_types::{H160, H256, U256};
+	use ethereum_types::Address;
+	use MAX_POLLING_DURATION;
+	use super::HardwareWalletManager;
 
-	let manager = Manager::new(
+	let manager = HardwareWalletManager::new().unwrap();
-		Arc::new(Mutex::new(hidapi::HidApi::new().expect("HidApi"))),
-		Arc::new(AtomicBool::new(false))
-	).expect("HardwareWalletManager");
 
-	let addr: Address = H160::from("some_addr");
+	assert_eq!(try_connect_polling(&manager.trezor, &MAX_POLLING_DURATION, DeviceDirection::Arrived), true);
 
-	assert_eq!(try_connect_polling(&manager.clone(), &POLLING_DURATION, DeviceDirection::Arrived), true);
+	let addr: Address = manager.list_wallets()
+		.iter()
+		.filter(|d| d.name == "TREZOR".to_string() && d.manufacturer == "SatoshiLabs".to_string())
+		.nth(0)
+		.map(|d| d.address)
+		.unwrap();
 
 	let t_info = TransactionInfo {
 		nonce: U256::from(1),
 		gas_price: U256::from(100),
 		gas_limit: U256::from(21_000),
-		to: Some(H160::from("some_other_addr")),
+		to: Some(Address::from(1337)),
-		chain_id: Some(17),
+		chain_id: Some(1),
 		value: U256::from(1_000_000),
 		data: (&[1u8; 3000]).to_vec(),
 	};
-	let signature = manager.sign_transaction(&addr, &t_info).unwrap();
-	let expected = Signature::from_rsv(
-		&H256::from("device_specific_r"),
-		&H256::from("device_specific_s"),
-		0x01
-		);
 
-	assert_eq!(signature, expected)
+	let signature = manager.trezor.sign_transaction(&addr, &t_info);
+	assert!(signature.is_ok());
 }