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VMCalls.cpp
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VMCalls.cpp
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/*
This file is part of cpp-ethereum.
cpp-ethereum is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
cpp-ethereum is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
#include "VM.h"
namespace dev
{
namespace eth
{
void VM::copyDataToMemory(bytesConstRef _data, u256*_sp)
{
auto offset = static_cast<size_t>(_sp[0]);
s512 bigIndex = _sp[1];
auto index = static_cast<size_t>(bigIndex);
auto size = static_cast<size_t>(_sp[2]);
size_t sizeToBeCopied = bigIndex + size > _data.size() ? _data.size() < bigIndex ? 0 : _data.size() - index : size;
if (sizeToBeCopied > 0)
std::memcpy(m_mem.data() + offset, _data.data() + index, sizeToBeCopied);
if (size > sizeToBeCopied)
std::memset(m_mem.data() + offset + sizeToBeCopied, 0, size - sizeToBeCopied);
}
// consolidate exception throws to avoid spraying boost code all over interpreter
void VM::throwOutOfGas()
{
BOOST_THROW_EXCEPTION(OutOfGas());
}
void VM::throwBadInstruction()
{
BOOST_THROW_EXCEPTION(BadInstruction());
}
void VM::throwBadJumpDestination()
{
BOOST_THROW_EXCEPTION(BadJumpDestination());
}
void VM::throwDisallowedStateChange()
{
BOOST_THROW_EXCEPTION(DisallowedStateChange());
}
// throwBadStack is called from fetchInstruction() -> adjustStack()
// its the only exception that can happen before ON_OP() log is done for an opcode case in VM.cpp
// so the call to m_onFail is needed here
void VM::throwBadStack(int _removed, int _added)
{
bigint size = m_stackEnd - m_SPP;
if (size < _removed)
BOOST_THROW_EXCEPTION(StackUnderflow() << RequirementError((bigint)_removed, size));
else
BOOST_THROW_EXCEPTION(OutOfStack() << RequirementError((bigint)(_added - _removed), size));
}
void VM::throwRevertInstruction(owning_bytes_ref&& _output)
{
// We can't use BOOST_THROW_EXCEPTION here because it makes a copy of exception inside and
// RevertInstruction has no copy constructor
throw RevertInstruction(std::move(_output));
}
void VM::throwBufferOverrun(bigint const& _endOfAccess)
{
BOOST_THROW_EXCEPTION(BufferOverrun() << RequirementError(_endOfAccess, bigint(m_returnData.size())));
}
int64_t VM::verifyJumpDest(u256 const& _dest, bool _throw)
{
// check for overflow
if (_dest <= 0x7FFFFFFFFFFFFFFF) {
// check for within bounds and to a jump destination
// use binary search of array because hashtable collisions are exploitable
uint64_t pc = uint64_t(_dest);
if (std::binary_search(m_jumpDests.begin(), m_jumpDests.end(), pc))
return pc;
}
if (_throw)
throwBadJumpDestination();
return -1;
}
//
// interpreter cases that call out
//
void VM::caseCreate()
{
m_bounce = &VM::interpretCases;
m_runGas = VMSchedule::createGas;
// Collect arguments.
u256 const endowment = m_SP[0];
u256 const initOff = m_SP[1];
u256 const initSize = m_SP[2];
u256 salt;
if (m_OP == Instruction::CREATE2)
{
salt = m_SP[3];
// charge for hashing initCode = GSHA3WORD * ceil(len(init_code) / 32)
m_runGas += toInt63((u512{initSize} + 31) / 32 * uint64_t{VMSchedule::sha3WordGas});
}
updateMem(memNeed(initOff, initSize));
updateIOGas();
// Clear the return data buffer. This will not free the memory.
m_returnData.clear();
u256 const balance = fromEvmC(m_context->host->get_balance(m_context, &m_message->destination));
if (balance >= endowment && m_message->depth < 1024)
{
evmc_message msg = {};
msg.gas = m_io_gas;
if (m_rev >= EVMC_TANGERINE_WHISTLE)
msg.gas -= msg.gas / 64;
// Get init code. Casts are safe because the memory cost has been paid.
auto off = static_cast<size_t>(initOff);
auto size = static_cast<size_t>(initSize);
msg.input_data = &m_mem[off];
msg.input_size = size;
msg.create2_salt = toEvmC(salt);
msg.sender = m_message->destination;
msg.depth = m_message->depth + 1;
msg.kind = m_OP == Instruction::CREATE ? EVMC_CREATE : EVMC_CREATE2; // FIXME: In EVMC move the kind to the top.
msg.value = toEvmC(endowment);
evmc_result result = m_context->host->call(m_context, &msg);
if (result.status_code == EVMC_SUCCESS)
m_SPP[0] = fromAddress(fromEvmC(result.create_address));
else
m_SPP[0] = 0;
m_returnData.assign(result.output_data, result.output_data + result.output_size);
m_io_gas -= (msg.gas - result.gas_left);
if (result.release)
result.release(&result);
}
else
m_SPP[0] = 0;
++m_PC;
}
void VM::caseCall()
{
m_bounce = &VM::interpretCases;
evmc_message msg = {};
// Clear the return data buffer. This will not free the memory.
m_returnData.clear();
bytesRef output;
if (caseCallSetup(msg, output))
{
evmc_result result = m_context->host->call(m_context, &msg);
m_returnData.assign(result.output_data, result.output_data + result.output_size);
bytesConstRef{&m_returnData}.copyTo(output);
m_SPP[0] = result.status_code == EVMC_SUCCESS ? 1 : 0;
m_io_gas += result.gas_left;
if (result.release)
result.release(&result);
}
else
{
m_SPP[0] = 0;
m_io_gas += msg.gas;
}
++m_PC;
}
bool VM::caseCallSetup(evmc_message& o_msg, bytesRef& o_output)
{
m_runGas = m_rev >= EVMC_TANGERINE_WHISTLE ? 700 : 40;
switch (m_OP)
{
case Instruction::CALL:
case Instruction::STATICCALL:
default:
o_msg.kind = EVMC_CALL;
break;
case Instruction::CALLCODE:
o_msg.kind = EVMC_CALLCODE;
break;
case Instruction::DELEGATECALL:
o_msg.kind = EVMC_DELEGATECALL;
break;
}
if (m_OP == Instruction::STATICCALL || m_message->flags & EVMC_STATIC)
o_msg.flags = EVMC_STATIC;
bool const haveValueArg = m_OP == Instruction::CALL || m_OP == Instruction::CALLCODE;
evmc_address destination = toEvmC(asAddress(m_SP[1]));
int destinationExists = m_context->host->account_exists(m_context, &destination);
if (m_OP == Instruction::CALL && !destinationExists)
{
if (m_SP[2] > 0 || m_rev < EVMC_SPURIOUS_DRAGON)
m_runGas += VMSchedule::callNewAccount;
}
if (haveValueArg && m_SP[2] > 0)
m_runGas += VMSchedule::valueTransferGas;
size_t const sizesOffset = haveValueArg ? 3 : 2;
u256 inputOffset = m_SP[sizesOffset];
u256 inputSize = m_SP[sizesOffset + 1];
u256 outputOffset = m_SP[sizesOffset + 2];
u256 outputSize = m_SP[sizesOffset + 3];
uint64_t inputMemNeed = memNeed(inputOffset, inputSize);
uint64_t outputMemNeed = memNeed(outputOffset, outputSize);
m_newMemSize = std::max(inputMemNeed, outputMemNeed);
updateMem(m_newMemSize);
updateIOGas();
// "Static" costs already applied. Calculate call gas.
u256 callGas = m_SP[0];
if (m_rev >= EVMC_TANGERINE_WHISTLE)
{
// Apply "all but one 64th" rule.
u256 maxAllowedCallGas = m_io_gas - m_io_gas / 64;
callGas = std::min(callGas, maxAllowedCallGas);
}
o_msg.gas = toInt63(callGas);
m_runGas = o_msg.gas;
updateIOGas();
o_msg.destination = destination;
o_msg.sender = m_message->destination;
o_msg.input_data = m_mem.data() + size_t(inputOffset);
o_msg.input_size = size_t(inputSize);
bool balanceOk = true;
if (haveValueArg)
{
u256 value = m_SP[2];
if (value > 0)
{
o_msg.value = toEvmC(m_SP[2]);
o_msg.gas += VMSchedule::callStipend;
{
u256 const balance =
fromEvmC(m_context->host->get_balance(m_context, &m_message->destination));
balanceOk = balance >= value;
}
}
}
else if (m_OP == Instruction::DELEGATECALL)
{
o_msg.sender = m_message->sender;
o_msg.value = m_message->value;
}
if (balanceOk && m_message->depth < 1024)
{
size_t outOff = size_t(outputOffset);
size_t outSize = size_t(outputSize);
o_output = bytesRef(m_mem.data() + outOff, outSize);
return true;
}
return false;
}
}
}