duytai/sguard

1. Getting started

Clone the project to project_folder/ and install dependencies

cd project_folder/
npm install && mkdir contracts/

Place the following contract to contracts/sample.sol

// contracts/sample.sol

pragma solidity^0.4.26;

contract Fund {
  mapping(address => uint) balances;
  uint counter = 0;
  uint dontFixMe = 0;

  function main(uint x) public {
    if (counter < 100) {
      msg.sender.send(x + 1);
      counter += 1;
      dontFixMe ++;
    }
  }
}

Run npm run dev to patch sample.sol. The fixed file is contracts/fixed.sol

//contracts/fixed.sol

contract sGuard{
  function add_uint256(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }

  bool internal locked_;
  constructor() internal {
    locked_ = false;
  }
  modifier nonReentrant_() {
    require(!locked_);
    locked_ = true;
    _;
    locked_ = false;
  }
}
pragma solidity^0.4.26;

contract Fund  is sGuard {
  mapping(address => uint) balances;
  uint counter = 0;
  uint dontFixMe = 0;

   function main(uint x) nonReentrant_  public {
    if (counter < 100) {
      msg.sender.send(add_uint256(x, 1));
      counter = add_uint256(counter, 1);
      dontFixMe ++;
    }
  }
}

Note: the source code is currently unstable. It will be refactored and updated soon