// SPDX-License-Identifier: MIT OR Apache-2.0 pragma solidity ^0.8.20; /// @dev copied from https://github.com/nomad-xyz/ExcessivelySafeCall/blob/main/src/ExcessivelySafeCall.sol. library SafeCall { /// @notice calls a contract with a specified gas limit and value and captures the return data /// @param _target The address to call /// @param _gas The amount of gas to forward to the remote contract /// @param _value The value in wei to send to the remote contract /// to memory. /// @param _maxCopy The maximum number of bytes of returndata to copy /// to memory. /// @param _calldata The data to send to the remote contract /// @return success and returndata, as `.call()`. Returndata is capped to /// `_maxCopy` bytes. function safeCall( address _target, uint256 _gas, uint256 _value, uint16 _maxCopy, bytes memory _calldata ) internal returns (bool, bytes memory) { // check that target has code uint size; assembly { size := extcodesize(_target) } if (size == 0) { return (false, new bytes(0)); } // set up for assembly call uint256 _toCopy; bool _success; bytes memory _returnData = new bytes(_maxCopy); // dispatch message to recipient // by assembly calling "handle" function // we call via assembly to avoid memcopying a very large returndata // returned by a malicious contract assembly { _success := call( _gas, // gas _target, // recipient _value, // ether value add(_calldata, 0x20), // inloc mload(_calldata), // inlen 0, // outloc 0 // outlen ) // limit our copy to 100 bytes _toCopy := returndatasize() if gt(_toCopy, _maxCopy) { _toCopy := _maxCopy } // Store the length of the copied bytes mstore(_returnData, _toCopy) // copy the bytes from returndata[0:_toCopy] returndatacopy(add(_returnData, 0x20), 0, _toCopy) } return (_success, _returnData); } /// @notice Use when you _really_ really _really_ don't trust the called /// contract. This prevents the called contract from causing reversion of /// the caller in as many ways as we can. /// @dev The main difference between this and a solidity low-level call is /// that we limit the number of bytes that the callee can cause to be /// copied to caller memory. This prevents stupid things like malicious /// contracts returning 10,000,000 bytes causing a local OOG when copying /// to memory. /// @param _target The address to call /// @param _gas The amount of gas to forward to the remote contract /// @param _maxCopy The maximum number of bytes of returndata to copy /// to memory. /// @param _calldata The data to send to the remote contract /// @return success and returndata, as `.call()`. Returndata is capped to /// `_maxCopy` bytes. function safeStaticCall( address _target, uint256 _gas, uint16 _maxCopy, bytes memory _calldata ) internal view returns (bool, bytes memory) { // check that target has code uint size; assembly { size := extcodesize(_target) } if (size == 0) { return (false, new bytes(0)); } // set up for assembly call uint256 _toCopy; bool _success; bytes memory _returnData = new bytes(_maxCopy); // dispatch message to recipient // by assembly calling "handle" function // we call via assembly to avoid memcopying a very large returndata // returned by a malicious contract assembly { _success := staticcall( _gas, // gas _target, // recipient add(_calldata, 0x20), // inloc mload(_calldata), // inlen 0, // outloc 0 // outlen ) // limit our copy to 256 bytes _toCopy := returndatasize() if gt(_toCopy, _maxCopy) { _toCopy := _maxCopy } // Store the length of the copied bytes mstore(_returnData, _toCopy) // copy the bytes from returndata[0:_toCopy] returndatacopy(add(_returnData, 0x20), 0, _toCopy) } return (_success, _returnData); } }