pragma solidity >=0.6.0; pragma solidity >=0.4.23; interface DSAuthority { function canCall( address src, address dst, bytes4 sig ) external view returns (bool); } contract DSAuthEvents { event LogSetAuthority (address indexed authority); event LogSetOwner (address indexed owner); } contract DSAuth is DSAuthEvents { DSAuthority public authority; address public owner; constructor() public { owner = msg.sender; emit LogSetOwner(msg.sender); } function setOwner(address owner_) public auth { owner = owner_; emit LogSetOwner(owner); } function setAuthority(DSAuthority authority_) public auth { authority = authority_; emit LogSetAuthority(address(authority)); } modifier auth { require(isAuthorized(msg.sender, msg.sig), "ds-auth-unauthorized"); _; } function isAuthorized(address src, bytes4 sig) internal view returns (bool) { if (src == address(this)) { return true; } else if (src == owner) { return true; } else if (authority == DSAuthority(0)) { return false; } else { return authority.canCall(src, address(this), sig); } } } contract DSNote { event LogNote( bytes4 indexed sig, address indexed guy, bytes32 indexed foo, bytes32 indexed bar, uint256 wad, bytes fax ) anonymous; modifier note { bytes32 foo; bytes32 bar; uint256 wad; assembly { foo := calldataload(4) bar := calldataload(36) wad := callvalue() } _; emit LogNote(msg.sig, msg.sender, foo, bar, wad, msg.data); } } // DSProxy // Allows code execution using a persistant identity This can be very // useful to execute a sequence of atomic actions. Since the owner of // the proxy can be changed, this allows for dynamic ownership models // i.e. a multisig contract DSProxy is DSAuth, DSNote { DSProxyCache public cache; // global cache for contracts constructor(address _cacheAddr) public { require(setCache(_cacheAddr)); } fallback() external payable { } receive() external payable { } // use the proxy to execute calldata _data on contract _code function execute(bytes memory _code, bytes memory _data) public payable returns (address target, bytes32 response) { target = cache.read(_code); if (target == address(0x0)) { // deploy contract & store its address in cache target = cache.write(_code); } response = execute(target, _data); } function execute(address _target, bytes memory _data) public auth note payable returns (bytes32 response) { require(_target != address(0x0)); // call contract in current context assembly { let succeeded := delegatecall(sub(gas(), 5000), _target, add(_data, 0x20), mload(_data), 0, 32) response := mload(0) // load delegatecall output switch iszero(succeeded) case 1 { // throw if delegatecall failed revert(0, 0) } } } //set new cache function setCache(address _cacheAddr) public auth note returns (bool) { require(_cacheAddr != address(0x0)); // invalid cache address cache = DSProxyCache(_cacheAddr); // overwrite cache return true; } } // DSProxyFactory // This factory deploys new proxy instances through build() // Deployed proxy addresses are logged contract DSProxyFactory { event Created(address indexed sender, address indexed owner, address proxy, address cache); mapping(address=>bool) public isProxy; DSProxyCache public cache = new DSProxyCache(); // deploys a new proxy instance // sets owner of proxy to caller function build() public returns (DSProxy proxy) { proxy = build(msg.sender); } // deploys a new proxy instance // sets custom owner of proxy function build(address owner) public returns (DSProxy proxy) { proxy = new DSProxy(address(cache)); emit Created(msg.sender, owner, address(proxy), address(cache)); proxy.setOwner(owner); isProxy[address(proxy)] = true; } } // DSProxyCache // This global cache stores addresses of contracts previously deployed // by a proxy. This saves gas from repeat deployment of the same // contracts and eliminates blockchain bloat. // By default, all proxies deployed from the same factory store // contracts in the same cache. The cache a proxy instance uses can be // changed. The cache uses the sha3 hash of a contract's bytecode to // lookup the address contract DSProxyCache { mapping(bytes32 => address) cache; function read(bytes memory _code) public view returns (address) { bytes32 hash = keccak256(_code); return cache[hash]; } function write(bytes memory _code) public returns (address target) { assembly { target := create(0, add(_code, 0x20), mload(_code)) switch iszero(extcodesize(target)) case 1 { // throw if contract failed to deploy revert(0, 0) } } bytes32 hash = keccak256(_code); cache[hash] = target; } }