Fixing delegatecall

src/action_params.rs

@@ -23,15 +23,17 @@ pub struct ActionParams {
 	pub gas_price: U256,
 	/// Transaction value.
 	pub value: U256,
+	/// Should transfer value from sender to origin
+	pub is_value_transfer: bool,
 	/// Code being executed.
 	pub code: Option<Bytes>,
 	/// Input data.
 	pub data: Option<Bytes>
 }
 
-impl ActionParams {
+impl Default for ActionParams {
-	/// TODO [Gav Wood] Please document me
+	/// Returns default ActionParams initialized with zeros
-	pub fn new() -> ActionParams {
+	fn default() -> ActionParams {
 		ActionParams {
 			code_address: Address::new(),
 			address: Address::new(),
@@ -41,7 +43,8 @@ impl ActionParams {
 			gas_price: U256::zero(),
 			value: U256::zero(),
 			code: None,
-			data: None
+			data: None,
+			is_value_transfer: true
 		}
 	}
 }

src/evm/ext.rs

@@ -26,7 +26,7 @@ pub enum MessageCallResult {
 	Failed
 }
 
-/// TODO [debris] Please document me
+/// Externalities interface for EVMs
 pub trait Ext {
 	/// Returns a value for given key.
 	fn storage_at(&self, key: &H256) -> H256;
@@ -61,6 +61,18 @@ pub trait Ext {
 			code_address: &Address, 
 			output: &mut [u8]) -> MessageCallResult;
 
+	/// Delegate Message call.
+	/// 
+	/// Returns Err, if we run out of gas.
+	/// Otherwise returns call_result which contains gas left 
+	/// and true if subcall was successfull.
+	fn delegatecall(&mut self, 
+			gas: &U256, 
+			value: &U256, 
+			data: &[u8], 
+			code_address: &Address, 
+			output: &mut [u8]) -> MessageCallResult;
+
 	/// Returns code at given address
 	fn extcode(&self, address: &Address) -> Bytes;
 

src/evm/interpreter.rs

@@ -564,17 +564,50 @@ impl Interpreter {
 					}
 				};
 			},
-			instructions::CALL | instructions::CALLCODE | instructions::DELEGATECALL => {
+			instructions::DELEGATECALL => {
+				let call_gas = stack.pop_back();
+				let code_address = stack.pop_back();
+				let code_address = u256_to_address(&code_address);
+
+				let value = params.value;
+
+				let in_off = stack.pop_back();
+				let in_size = stack.pop_back();
+				let out_off = stack.pop_back();
+				let out_size = stack.pop_back();
+
+				let can_call = ext.depth() < ext.schedule().max_depth;
+				if !can_call {
+					stack.push(U256::zero());
+					return Ok(InstructionResult::UnusedGas(call_gas));
+				}
+
+				let call_result = {
+					// we need to write and read from memory in the same time
+					// and we don't want to copy
+					let input = unsafe { ::std::mem::transmute(mem.read_slice(in_off, in_size)) };
+					let output = mem.writeable_slice(out_off, out_size);
+					ext.delegatecall(&call_gas, &value, input, &code_address, output)
+				};
+
+				return match call_result {
+					MessageCallResult::Success(gas_left) => {
+						stack.push(U256::one());
+						Ok(InstructionResult::UnusedGas(gas_left))
+					},
+					MessageCallResult::Failed  => {
+						stack.push(U256::zero());
+						Ok(InstructionResult::Ok)
+					}
+				};
+			},
+			instructions::CALL | instructions::CALLCODE => {
 				assert!(ext.schedule().call_value_transfer_gas > ext.schedule().call_stipend, "overflow possible");
 				let call_gas = stack.pop_back();
 				let code_address = stack.pop_back();
 				let code_address = u256_to_address(&code_address);
-				let is_delegatecall = instruction == instructions::DELEGATECALL;
 
-				let value = match is_delegatecall {
+				let value = stack.pop_back();
-					true => params.value,
-					false => stack.pop_back()
-				};
 
 				let address = match instruction == instructions::CALL {
 					true => &code_address,
@@ -586,12 +619,12 @@ impl Interpreter {
 				let out_off = stack.pop_back();
 				let out_size = stack.pop_back();
 
-				let call_gas = call_gas + match !is_delegatecall && value > U256::zero() {
+				let call_gas = call_gas + match value > U256::zero() {
 					true => U256::from(ext.schedule().call_stipend),
 					false => U256::zero()
 				};
 
-				let can_call = (is_delegatecall || ext.balance(&params.address) >= value) && ext.depth() < ext.schedule().max_depth;
+				let can_call = ext.balance(&params.address) >= value && ext.depth() < ext.schedule().max_depth;
 
 				if !can_call {
 					stack.push(U256::zero());

src/evm/tests.rs

@@ -69,6 +69,15 @@ impl Ext for FakeExt {
 		unimplemented!();
 	}
 
+	fn delegatecall(&mut self, 
+			_gas: &U256, 
+			_value: &U256, 
+			_data: &[u8], 
+			_address: &Address, 
+			_output: &mut [u8]) -> MessageCallResult {
+		unimplemented!();
+	}
+
 	fn extcode(&self, address: &Address) -> Bytes {
 		self.codes.get(address).unwrap_or(&Bytes::new()).clone()
 	}
@@ -110,7 +119,7 @@ fn test_stack_underflow() {
 	let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "01600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -137,7 +146,7 @@ fn test_add(factory: super::Factory) {
   let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff01600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -157,7 +166,7 @@ fn test_sha3(factory: super::Factory) {
 	let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "6000600020600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -177,7 +186,7 @@ fn test_address(factory: super::Factory) {
 	let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "30600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -198,7 +207,7 @@ fn test_origin(factory: super::Factory) {
 	let origin = Address::from_str("cd1722f2947def4cf144679da39c4c32bdc35681").unwrap();
 	let code = "32600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.origin = origin.clone();
 	params.gas = U256::from(100_000);
@@ -220,7 +229,7 @@ fn test_sender(factory: super::Factory) {
 	let sender = Address::from_str("cd1722f2947def4cf144679da39c4c32bdc35681").unwrap();
 	let code = "33600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.sender = sender.clone();
 	params.gas = U256::from(100_000);
@@ -254,7 +263,7 @@ fn test_extcodecopy(factory: super::Factory) {
 	let code = "333b60006000333c600051600055".from_hex().unwrap();
 	let sender_code = "6005600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.sender = sender.clone();
 	params.gas = U256::from(100_000);
@@ -276,7 +285,7 @@ fn test_log_empty(factory: super::Factory) {
 	let address = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "60006000a0".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -307,7 +316,7 @@ fn test_log_sender(factory: super::Factory) {
 	let sender = Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap();
 	let code = "60ff6000533360206000a1".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.sender = sender.clone();
 	params.gas = U256::from(100_000);
@@ -332,7 +341,7 @@ fn test_blockhash(factory: super::Factory) {
 	let code = "600040600055".from_hex().unwrap();
 	let blockhash = H256::from_str("123400000000000000000000cd1722f2947def4cf144679da39c4c32bdc35681").unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -354,7 +363,7 @@ fn test_calldataload(factory: super::Factory) {
 	let code = "600135600055".from_hex().unwrap();
 	let data = "0123ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff23".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.address = address.clone();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
@@ -376,7 +385,7 @@ fn test_author(factory: super::Factory) {
 	let author = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 	let code = "41600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
 	let mut ext = FakeExt::new();
@@ -396,7 +405,7 @@ fn test_timestamp(factory: super::Factory) {
 	let timestamp = 0x1234; 
 	let code = "42600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
 	let mut ext = FakeExt::new();
@@ -416,7 +425,7 @@ fn test_number(factory: super::Factory) {
 	let number = 0x1234; 
 	let code = "43600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
 	let mut ext = FakeExt::new();
@@ -436,7 +445,7 @@ fn test_difficulty(factory: super::Factory) {
 	let difficulty = U256::from(0x1234);
 	let code = "44600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
 	let mut ext = FakeExt::new();
@@ -456,7 +465,7 @@ fn test_gas_limit(factory: super::Factory) {
 	let gas_limit = U256::from(0x1234);
 	let code = "45600055".from_hex().unwrap();
 
-	let mut params = ActionParams::new();
+	let mut params = ActionParams::default();
 	params.gas = U256::from(100_000);
 	params.code = Some(code);
 	let mut ext = FakeExt::new();

src/executive.rs

@@ -134,6 +134,7 @@ impl<'a> Executive<'a> {
 					gas: init_gas,
 					gas_price: t.gas_price,
 					value: t.value,
+					is_value_transfer: true,
 					code: Some(t.data.clone()),
 					data: None,
 				};
@@ -148,6 +149,7 @@ impl<'a> Executive<'a> {
 					gas: init_gas,
 					gas_price: t.gas_price,
 					value: t.value,
+					is_value_transfer: true,
 					code: self.state.code(address),
 					data: Some(t.data.clone()),
 				};
@@ -166,11 +168,14 @@ impl<'a> Executive<'a> {
 	/// Modifies the substate and the output.
 	/// Returns either gas_left or `evm::Error`.
 	pub fn call(&mut self, params: ActionParams, substate: &mut Substate, mut output: BytesRef) -> evm::Result {
+    println!("Calling executive. Sender: {}", params.sender);
 		// backup used in case of running out of gas
 		let backup = self.state.clone();
 
 		// at first, transfer value to destination
-		self.state.transfer_balance(&params.sender, &params.address, &params.value);
+		if params.is_value_transfer {
+			self.state.transfer_balance(&params.sender, &params.address, &params.value);
+		}
 		trace!("Executive::call(params={:?}) self.env_info={:?}", params, self.info);
 
 		if self.engine.is_builtin(&params.code_address) {
@@ -227,7 +232,9 @@ impl<'a> Executive<'a> {
 		self.state.new_contract(&params.address);
 
 		// then transfer value to it
-		self.state.transfer_balance(&params.sender, &params.address, &params.value);
+		if params.is_value_transfer {
+			self.state.transfer_balance(&params.sender, &params.address, &params.value);
+		}
 
 		let res = {
 			let mut ext = self.to_externalities(OriginInfo::from(&params), &mut unconfirmed_substate, OutputPolicy::InitContract);
@@ -367,7 +374,7 @@ mod tests {
 	fn test_sender_balance(factory: Factory) {
 		let sender = Address::from_str("0f572e5295c57f15886f9b263e2f6d2d6c7b5ec6").unwrap();
 		let address = contract_address(&sender, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.sender = sender.clone();
 		params.gas = U256::from(100_000);
@@ -424,7 +431,7 @@ mod tests {
 		let address = contract_address(&sender, &U256::zero());
 		// TODO: add tests for 'callcreate'
 		//let next_address = contract_address(&address, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.sender = sender.clone();
 		params.origin = sender.clone();
@@ -477,7 +484,7 @@ mod tests {
 		let address = contract_address(&sender, &U256::zero());
 		// TODO: add tests for 'callcreate'
 		//let next_address = contract_address(&address, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.sender = sender.clone();
 		params.origin = sender.clone();
@@ -528,7 +535,7 @@ mod tests {
 		let sender = Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap();
 		let address = contract_address(&sender, &U256::zero());
 		let next_address = contract_address(&address, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.sender = sender.clone();
 		params.origin = sender.clone();
@@ -584,7 +591,7 @@ mod tests {
 		let address_b = Address::from_str("945304eb96065b2a98b57a48a06ae28d285a71b5" ).unwrap();
 		let sender = Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap();
 
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address_a.clone();
 		params.sender = sender.clone();
 		params.gas = U256::from(100_000);
@@ -633,7 +640,7 @@ mod tests {
 		let sender = Address::from_str("cd1722f3947def4cf144679da39c4c32bdc35681").unwrap();
 		let code = "600160005401600055600060006000600060003060e05a03f1600155".from_hex().unwrap();
 		let address = contract_address(&sender, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.gas = U256::from(100_000);
 		params.code = Some(code.clone());
@@ -789,7 +796,7 @@ mod tests {
 		let address = contract_address(&sender, &U256::zero());
 		// TODO: add tests for 'callcreate'
 		//let next_address = contract_address(&address, &U256::zero());
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		params.address = address.clone();
 		params.sender = sender.clone();
 		params.origin = sender.clone();

src/externalities.rs

@@ -17,6 +17,7 @@ pub enum OutputPolicy<'a> {
 
 /// Transaction properties that externalities need to know about.
 pub struct OriginInfo {
+	sender: Address,
 	address: Address,
 	origin: Address,
 	gas_price: U256
@@ -26,6 +27,7 @@ impl OriginInfo {
 	/// Populates origin info from action params.
 	pub fn from(params: &ActionParams) -> Self {
 		OriginInfo {
+			sender: params.sender.clone(),
 			address: params.address.clone(),
 			origin: params.origin.clone(),
 			gas_price: params.gas_price.clone()
@@ -112,6 +114,7 @@ impl<'a> Ext for Externalities<'a> {
 			gas: *gas,
 			gas_price: self.origin_info.gas_price.clone(),
 			value: value.clone(),
+			is_value_transfer: true,
 			code: Some(code.to_vec()),
 			data: None,
 		};
@@ -129,6 +132,34 @@ impl<'a> Ext for Externalities<'a> {
 		}
 	}
 
+	fn delegatecall(&mut self, 
+			gas: &U256, 
+			value: &U256, 
+			data: &[u8], 
+			code_address: &Address, 
+			output: &mut [u8]) -> MessageCallResult {
+
+		let params = ActionParams {
+			code_address: code_address.clone(),
+			address: self.origin_info.address.clone(), 
+			sender: self.origin_info.sender.clone(),
+			origin: self.origin_info.origin.clone(),
+			gas: *gas,
+			gas_price: self.origin_info.gas_price.clone(),
+			value: value.clone(),
+			is_value_transfer: false,
+			code: self.state.code(code_address),
+			data: Some(data.to_vec()),
+		};
+
+		let mut ex = Executive::from_parent(self.state, self.env_info, self.engine, self.depth);
+    
+		match ex.call(params, self.substate, BytesRef::Fixed(output)) {
+			Ok(gas_left) => MessageCallResult::Success(gas_left),
+			_ => MessageCallResult::Failed
+		}
+  }
+
 	fn call(&mut self, 
 			gas: &U256, 
 			address: &Address, 
@@ -145,6 +176,7 @@ impl<'a> Ext for Externalities<'a> {
 			gas: *gas,
 			gas_price: self.origin_info.gas_price.clone(),
 			value: value.clone(),
+			is_value_transfer: true,
 			code: self.state.code(code_address),
 			data: Some(data.to_vec()),
 		};

src/tests/executive.rs

@@ -115,6 +115,22 @@ impl<'a> Ext for TestExt<'a> {
 		MessageCallResult::Success(*gas)
 	}
 
+	fn delegatecall(&mut self, 
+			gas: &U256, 
+			value: &U256, 
+			data: &[u8], 
+			_code_address: &Address, 
+			_output: &mut [u8]) -> MessageCallResult {
+
+		self.callcreates.push(CallCreate {
+			data: data.to_vec(),
+			destination: None,
+			gas_limit: *gas,
+			value: *value
+		});
+		MessageCallResult::Success(*gas)
+	}
+
 	fn extcode(&self, address: &Address) -> Bytes  {
 		self.ext.extcode(address)
 	}
@@ -200,7 +216,7 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
 		let engine = TestEngine::new(1, vm.clone());
 
 		// params
-		let mut params = ActionParams::new();
+		let mut params = ActionParams::default();
 		test.find("exec").map(|exec| {
 			params.address = xjson!(&exec["address"]);
 			params.sender = xjson!(&exec["caller"]);