Fountain 合约解析
2018-10-30 本文已影响64人
uestcAries
大体来说， 合约分为如下几个模块：
1： 合约逻辑控制分析、
2： FTN源码部分分析、
3： 合约安全性分析、
4： 合约合理性分析、
5：个人对FTN合约分析、
fountain官网： https://fountainhub.com/
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最近也在以太坊上看到部署了fountain ico的合约：https://etherscan.io/token/0x82cf44be0768a3600c4bdea58607783a3a7c51ae
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fountain白皮书： https://www.jianshu.com/p/1a73af5a2eeb
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上图可知fountain 已经转移了一部分代币到其他账户， 我们期待的FTN终于开始行动了， 不过作为我们个人似乎前面基本没戏进入私募轮， 所以我也只有期待A轮的公募
那么白皮书提到了关于TOKEN 初始化分配已经后面的增发， 还有FP等等， 又如何从合约去体现呢？ 那么下面我将仔细的来和大家聊一聊。
fountain 合约代码：
pragma solidity ^0.4.25;
library SafeMath {
function mul (uint256 a, uint256 b) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
uint256 c = a * b;
assert(c / a == b);
return c;
}
function div (uint256 a, uint256 b) internal pure returns (uint256) {
return a / b;
}
function sub (uint256 a, uint256 b) internal pure returns (uint256) {
assert(b <= a);
return a - b;
}
function add (uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
assert(c >= a);
return c;
}
}
contract ERCBasic {
event Transfer(address indexed from, address indexed to, uint256 value);
function totalSupply () public view returns (uint256);
function balanceOf (address who) public view returns (uint256);
function transfer (address to, uint256 value) public returns (bool);
}
contract ERC is ERCBasic {
event Approval(address indexed owner, address indexed spender, uint256 value);
function transferFrom (address from, address to, uint256 value) public returns (bool);
function allowance (address owner, address spender) public view returns (uint256);
function approve (address spender, uint256 value) public returns (bool);
}
contract Ownable {
event OwnershipTransferred(address indexed oldone, address indexed newone);
event FoundationOwnershipTransferred(address indexed oldFoundationOwner, address indexed newFoundationOwner);
address internal owner;
address internal foundationOwner;
constructor () public {
owner = msg.sender;
foundationOwner = owner;
}
modifier onlyOwner () {
require(msg.sender == owner);
_;
}
modifier hasMintability () {
require(msg.sender == owner || msg.sender == foundationOwner);
_;
}
function transferOwnership (address newOwner) public returns (bool);
function setFountainFoundationOwner (address foundation) public returns (bool);
}
contract Pausable is Ownable {
event ContractPause();
event ContractResume();
event ContractPauseSchedule(uint256 from, uint256 to);
uint256 internal pauseFrom;
uint256 internal pauseTo;
modifier whenRunning () {
require(now < pauseFrom || now > pauseTo);
_;
}
modifier whenPaused () {
require(now >= pauseFrom && now <= pauseTo);
_;
}
function pause () public onlyOwner {
pauseFrom = now - 1;
pauseTo = now + 30000 days;
emit ContractPause();
}
function pause (uint256 from, uint256 to) public onlyOwner {
require(to > from);
pauseFrom = from;
pauseTo = to;
emit ContractPauseSchedule(from, to);
}
function resume () public onlyOwner {
pauseFrom = now - 2;
pauseTo = now - 1;
emit ContractResume();
}
}
contract TokenForge is Ownable {
event ForgeStart();
event ForgeStop();
bool public forge_running = true;
modifier canForge () {
require(forge_running);
_;
}
modifier cannotForge () {
require(!forge_running);
_;
}
function startForge () public onlyOwner cannotForge returns (bool) {
forge_running = true;
emit ForgeStart();
return true;
}
function stopForge () public onlyOwner canForge returns (bool) {
forge_running = false;
emit ForgeStop();
return true;
}
}
contract CappedToken is Ownable {
using SafeMath for uint256;
uint256 public token_cap;
uint256 public token_created;
uint256 public token_foundation_cap;
uint256 public token_foundation_created;
constructor (uint256 _cap, uint256 _foundationCap) public {
token_cap = _cap;
token_foundation_cap = _foundationCap;
}
function changeCap (uint256 _cap) public onlyOwner returns (bool) {
if (_cap < token_created && _cap > 0) return false;
token_cap = _cap;
return true;
}
function canMint (uint256 amount) public view returns (bool) {
return (token_cap == 0) || (token_created.add(amount) <= token_cap);
}
function canMintFoundation(uint256 amount) internal view returns(bool) {
return(token_foundation_created.add(amount) <= token_foundation_cap);
}
}
contract BasicToken is ERCBasic, Pausable {
using SafeMath for uint256;
mapping(address => uint256) public wallets;
modifier canTransfer (address _from, address _to, uint256 amount) {
require((_from != address(0)) && (_to != address(0)));
require(_from != _to);
require(amount > 0);
_;
}
function balanceOf (address user) public view returns (uint256) {
return wallets[user];
}
}
contract DelegatableToken is ERC, BasicToken {
using SafeMath for uint256;
mapping(address => mapping(address => uint256)) public warrants;
function allowance (address owner, address delegator) public view returns (uint256) {
return warrants[owner][delegator];
}
function approve (address delegator, uint256 value) public whenRunning returns (bool) {
if (delegator == msg.sender) return true;
warrants[msg.sender][delegator] = value;
emit Approval(msg.sender, delegator, value);
return true;
}
function increaseApproval (address delegator, uint256 delta) public whenRunning returns (bool) {
if (delegator == msg.sender) return true;
uint256 value = warrants[msg.sender][delegator].add(delta);
warrants[msg.sender][delegator] = value;
emit Approval(msg.sender, delegator, value);
return true;
}
function decreaseApproval (address delegator, uint256 delta) public whenRunning returns (bool) {
if (delegator == msg.sender) return true;
uint256 value = warrants[msg.sender][delegator];
if (value < delta) {
value = 0;
}
else {
value = value.sub(delta);
}
warrants[msg.sender][delegator] = value;
emit Approval(msg.sender, delegator, value);
return true;
}
}
contract LockableProtocol is BasicToken {
function invest (address investor, uint256 amount) public returns (bool);
function getInvestedToken (address investor) public view returns (uint256);
function getLockedToken (address investor) public view returns (uint256);
function availableWallet (address user) public view returns (uint256) {
return wallets[user].sub(getLockedToken(user));
}
}
contract MintAndBurnToken is TokenForge, CappedToken, LockableProtocol {
using SafeMath for uint256;
event Mint(address indexed user, uint256 amount);
event Burn(address indexed user, uint256 amount);
constructor (uint256 _initial, uint256 _cap, uint256 _fountainCap) public CappedToken(_cap, _fountainCap) {
token_created = _initial;
wallets[msg.sender] = _initial;
emit Mint(msg.sender, _initial);
emit Transfer(address(0), msg.sender, _initial);
}
function totalSupply () public view returns (uint256) {
return token_created;
}
function totalFountainSupply() public view returns(uint256) {
return token_foundation_created;
}
function mint (address target, uint256 amount) public hasMintability whenRunning canForge returns (bool) {
require(target != owner && target != foundationOwner); // Owner和FoundationOwner不能成为mint的对象
require(canMint(amount));
if (msg.sender == foundationOwner) {
require(canMintFoundation(amount));
token_foundation_created = token_foundation_created.add(amount);
}
token_created = token_created.add(amount);
wallets[target] = wallets[target].add(amount);
emit Mint(target, amount);
emit Transfer(address(0), target, amount);
return true;
}
function burn (uint256 amount) public whenRunning canForge returns (bool) {
uint256 balance = availableWallet(msg.sender);
require(amount <= balance);
token_created = token_created.sub(amount);
wallets[msg.sender] -= amount;
emit Burn(msg.sender, amount);
emit Transfer(msg.sender, address(0), amount);
return true;
}
}
contract LockableToken is MintAndBurnToken, DelegatableToken {
using SafeMath for uint256;
struct LockBin {
uint256 start;
uint256 finish;
uint256 duration;
uint256 amount;
}
event InvestStart();
event InvestStop();
event NewInvest(uint256 release_start, uint256 release_duration);
uint256 public releaseStart;
uint256 public releaseDuration;
bool public forceStopInvest;
mapping(address => mapping(uint => LockBin)) public lockbins;
modifier canInvest () {
require(!forceStopInvest);
_;
}
constructor (uint256 _initial, uint256 _cap, uint256 _fountainCap) public MintAndBurnToken(_initial, _cap, _fountainCap) {
forceStopInvest = true;
}
function pauseInvest () public onlyOwner whenRunning returns (bool) {
require(!forceStopInvest);
forceStopInvest = true;
emit InvestStop();
return true;
}
function resumeInvest () public onlyOwner whenRunning returns (bool) {
require(forceStopInvest);
forceStopInvest = false;
emit InvestStart();
return true;
}
function setInvest (uint256 release_start, uint256 release_duration) public onlyOwner whenRunning returns (bool) {
releaseStart = release_start;
releaseDuration = release_duration;
forceStopInvest = false;
emit NewInvest(release_start, release_duration);
return true;
}
function invest (address investor, uint256 amount) public onlyOwner whenRunning canInvest returns (bool) {
require(investor != address(0));
require(investor != owner);
require(investor != foundationOwner);
require(amount > 0);
require(canMint(amount));
mapping(uint => LockBin) locks = lockbins[investor];
LockBin storage info = locks[0];
uint index = info.amount + 1;
locks[index] = LockBin({
start: releaseStart,
finish: releaseStart + releaseDuration,
duration: releaseDuration / (1 days),
amount: amount
});
info.amount = index;
token_created = token_created.add(amount);
wallets[investor] = wallets[investor].add(amount);
emit Mint(investor, amount);
emit Transfer(address(0), investor, amount);
return true;
}
function batchInvest (address[] investors, uint256 amount) public onlyOwner whenRunning canInvest returns (bool) {
require(amount > 0);
uint investorsLength = investors.length;
uint investorsCount = 0;
uint i;
address r;
for (i = 0; i < investorsLength; i ++) {
r = investors[i];
if (r == address(0) || r == owner || r == foundationOwner) continue;
investorsCount ++;
}
require(investorsCount > 0);
uint256 totalAmount = amount.mul(uint256(investorsCount));
require(canMint(totalAmount));
token_created = token_created.add(totalAmount);
for (i = 0; i < investorsLength; i ++) {
r = investors[i];
if (r == address(0) || r == owner || r == foundationOwner) continue;
mapping(uint => LockBin) locks = lockbins[r];
LockBin storage info = locks[0];
uint index = info.amount + 1;
locks[index] = LockBin({
start: releaseStart,
finish: releaseStart + releaseDuration,
duration: releaseDuration / (1 days),
amount: amount
});
info.amount = index;
wallets[r] = wallets[r].add(amount);
emit Mint(r, amount);
emit Transfer(address(0), r, amount);
}
return true;
}
function batchInvests (address[] investors, uint256[] amounts) public onlyOwner whenRunning canInvest returns (bool) {
uint investorsLength = investors.length;
require(investorsLength == amounts.length);
uint investorsCount = 0;
uint256 totalAmount = 0;
uint i;
address r;
for (i = 0; i < investorsLength; i ++) {
r = investors[i];
if (r == address(0) || r == owner) continue;
investorsCount ++;
totalAmount += amounts[i];
}
require(totalAmount > 0);
require(canMint(totalAmount));
uint256 amount;
token_created = token_created.add(totalAmount);
for (i = 0; i < investorsLength; i ++) {
r = investors[i];
if (r == address(0) || r == owner) continue;
amount = amounts[i];
wallets[r] = wallets[r].add(amount);
emit Mint(r, amount);
emit Transfer(address(0), r, amount);
mapping(uint => LockBin) locks = lockbins[r];
LockBin storage info = locks[0];
uint index = info.amount + 1;
locks[index] = LockBin({
start: releaseStart,
finish: releaseStart + releaseDuration,
duration: releaseDuration / (1 days),
amount: amount
});
info.amount = index;
}
return true;
}
function getInvestedToken (address investor) public view returns (uint256) {
require(investor != address(0) && investor != owner && investor != foundationOwner);
mapping(uint => LockBin) locks = lockbins[investor];
uint256 balance = 0;
uint l = locks[0].amount;
for (uint i = 1; i <= l; i ++) {
LockBin memory bin = locks[i];
balance = balance.add(bin.amount);
}
return balance;
}
function getLockedToken (address investor) public view returns (uint256) {
require(investor != address(0) && investor != owner && investor != foundationOwner);
mapping(uint => LockBin) locks = lockbins[investor];
uint256 balance = 0;
uint256 d = 1;
uint l = locks[0].amount;
for (uint i = 1; i <= l; i ++) {
LockBin memory bin = locks[i];
if (now <= bin.start) {
balance = balance.add(bin.amount);
}
else if (now < bin.finish) {
d = (now - bin.start) / (1 days);
balance = balance.add(bin.amount - bin.amount * d / bin.duration);
}
}
return balance;
}
function canPay (address user, uint256 amount) internal view returns (bool) {
uint256 balance = availableWallet(user);
return amount <= balance;
}
function transfer (address target, uint256 value) public whenRunning canTransfer(msg.sender, target, value) returns (bool) {
require(target != owner);
require(canPay(msg.sender, value));
wallets[msg.sender] = wallets[msg.sender].sub(value);
wallets[target] = wallets[target].add(value);
emit Transfer(msg.sender, target, value);
return true;
}
function batchTransfer (address[] receivers, uint256 amount) public whenRunning returns (bool) {
require(amount > 0);
uint receiveLength = receivers.length;
uint receiverCount = 0;
uint i;
address r;
for (i = 0; i < receiveLength; i ++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
receiverCount ++;
}
require(receiverCount > 0);
uint256 totalAmount = amount.mul(uint256(receiverCount));
require(canPay(msg.sender, totalAmount));
wallets[msg.sender] -= totalAmount;
for (i = 0; i < receiveLength; i++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
wallets[r] = wallets[r].add(amount);
emit Transfer(msg.sender, r, amount);
}
return true;
}
function batchTransfers (address[] receivers, uint256[] amounts) public whenRunning returns (bool) {
uint receiveLength = receivers.length;
require(receiveLength == amounts.length);
uint receiverCount = 0;
uint256 totalAmount = 0;
uint i;
address r;
for (i = 0; i < receiveLength; i ++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
receiverCount ++;
totalAmount += amounts[i];
}
require(totalAmount > 0);
require(canPay(msg.sender, totalAmount));
wallets[msg.sender] -= totalAmount;
uint256 amount;
for (i = 0; i < receiveLength; i++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
amount = amounts[i];
if (amount == 0) continue;
wallets[r] = wallets[r].add(amount);
emit Transfer(msg.sender, r, amount);
}
return true;
}
function transferFrom (address from, address to, uint256 value) public whenRunning canTransfer(from, to, value) returns (bool) {
require(from != owner);
require(to != owner);
require(canPay(from, value));
uint256 warrant;
if (msg.sender != from) {
warrant = warrants[from][msg.sender];
require(value <= warrant);
warrants[from][msg.sender] = warrant.sub(value);
}
wallets[from] = wallets[from].sub(value);
wallets[to] = wallets[to].add(value);
emit Transfer(from, to, value);
return true;
}
function batchTransferFrom (address from, address[] receivers, uint256 amount) public whenRunning returns (bool) {
require(from != address(0) && from != owner);
require(amount > 0);
uint receiveLength = receivers.length;
uint receiverCount = 0;
uint i;
address r;
for (i = 0; i < receiveLength; i ++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
receiverCount ++;
}
require(receiverCount > 0);
uint256 totalAmount = amount.mul(uint256(receiverCount));
require(canPay(from, totalAmount));
uint256 warrant;
if (msg.sender != from) {
warrant = warrants[from][msg.sender];
require(totalAmount <= warrant);
warrants[from][msg.sender] = warrant.sub(totalAmount);
}
wallets[from] -= totalAmount;
for (i = 0; i < receiveLength; i++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
wallets[r] = wallets[r].add(amount);
emit Transfer(from, r, amount);
}
return true;
}
function batchTransferFroms (address from, address[] receivers, uint256[] amounts) public whenRunning returns (bool) {
require(from != address(0) && from != owner);
uint receiveLength = receivers.length;
require(receiveLength == amounts.length);
uint receiverCount = 0;
uint256 totalAmount = 0;
uint i;
address r;
for (i = 0; i < receiveLength; i ++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
receiverCount ++;
totalAmount += amounts[i];
}
require(totalAmount > 0);
require(canPay(from, totalAmount));
uint256 warrant;
if (msg.sender != from) {
warrant = warrants[from][msg.sender];
require(totalAmount <= warrant);
warrants[from][msg.sender] = warrant.sub(totalAmount);
}
wallets[from] -= totalAmount;
uint256 amount;
for (i = 0; i < receiveLength; i++) {
r = receivers[i];
if (r == address(0) || r == owner) continue;
amount = amounts[i];
if (amount == 0) continue;
wallets[r] = wallets[r].add(amount);
emit Transfer(from, r, amount);
}
return true;
}
}
contract FountainToken is LockableToken {
string public constant name = "Fountain";
string public constant symbol = "FTN";
uint8 public constant decimals = 18;
uint256 private constant TOKEN_CAP = 10000000000 * 10 ** uint256(decimals);
uint256 private constant TOKEN_FOUNDATION_CAP = 300000000 * 10 ** uint256(decimals);
uint256 private constant TOKEN_INITIAL = 0 * 10 ** uint256(decimals);
constructor () public LockableToken(TOKEN_INITIAL, TOKEN_CAP, TOKEN_FOUNDATION_CAP) {
}
function suicide () public onlyOwner {
selfdestruct(owner);
}
function transferOwnership (address newOwner) public onlyOwner returns (bool) {
require(newOwner != address(0));
require(newOwner != owner);
require(newOwner != foundationOwner);
require(wallets[owner] == 0);
require(wallets[newOwner] == 0);
address oldOwner = owner;
owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
return true;
}
function setFountainFoundationOwner (address newFoundationOwner) public onlyOwner returns (bool) {
require(newFoundationOwner != address(0));
require(newFoundationOwner != foundationOwner);
require(newFoundationOwner != owner);
require(wallets[newFoundationOwner] == 0);
address oldFoundation = foundationOwner;
foundationOwner = newFoundationOwner;
emit FoundationOwnershipTransferred(oldFoundation, foundationOwner);
uint256 all = wallets[oldFoundation];
wallets[oldFoundation] -= all;
wallets[newFoundationOwner] = all;
emit Transfer(oldFoundation, newFoundationOwner, all);
return true;
}
}
1： 合约逻辑控制分析、
1.1 合约控制还是非常细化，使用安全计算法进行加减乘除运算（SafeMath）来控制所有计算操作
1.2 兼容官方基础 ERC20 代币协议， 也就是说能支持官方支持的钱包操作
contract ERCBasic {
event Transfer(address indexed from, address indexed to, uint256 value);
function totalSupply () public view returns (uint256);
function balanceOf (address who) public view returns (uint256);
function transfer (address to, uint256 value) public returns (bool);
}
1.3 合约可暂停
contract Pausable is Ownable
1.4 合约有自己独立的铸币厂
contract TokenForge is Ownable
1.5 铸币上限设置
contract CappedToken is Ownable
1.6 如何对FTN进行锁仓
contract LockableProtocol is BasicToke
1.7 FTN 代币主函数
contract FountainToken is LockableToken {
uint256 private constant TOKEN_CAP = 10000000000 * 10 ** uint256(decimals);
uint256 private constant TOKEN_FOUNDATION_CAP = 300000000 * 10 ** uint256(decimals);
uint256 private constant TOKEN_INITIAL = 0 * 10 ** uint256(decimals);
constructor () public LockableToken(TOKEN_INITIAL, TOKEN_CAP, TOKEN_FOUNDATION_CAP) {
}
}
2： FTN源码部分分析、
uint256 private constant TOKEN_CAP = 10000000000 * 10 ** uint256(decimals);
//TOKEN_CAP 说明这个FTN合约的增发上限， 不能超过这个值,
//后面这个函数看出始终是小于token_cap， 那么还得注意一点的是
//token_cap 此处为0， 那么就说明FTN可以无限制的增发，
//那么这样和比特币就有很大的差距， 那么官方给出的是有限制的
function canMint (uint256 amount) public view returns (bool) {
return (token_cap == 0) || (token_created.add(amount) <= token_cap);
}
uint256 private constant TOKEN_FOUNDATION_CAP = 300000000 * 10 ** uint256(decimals);
// fountain 基金会最大FTN
function canMintFoundation(uint256 amount) internal view returns(bool) {
return(token_foundation_created.add(amount) <= token_foundation_cap);
}
//说你基金会产生的不允许超过这个值， fountain 这个也是我比较满意的
//FTN初始化0
uint256 private constant TOKEN_INITIAL = 0 * 10 ** uint256(decimals);
struct LockBin {
uint256 start; //当前轮募资资金解冻开始时间
uint256 finish; // 当前轮募资解冻周期时长
uint256 duration;//解锁周期
uint256 amount; //FTN数量
}
//这个就比较重要 了， 这个可是保存了我们所有账户的FTN,
function invest (address investor, uint256 amount) public onlyOwner whenRunning canInvest returns (bool) {
require(investor != address(0));
require(investor != owner); // 管理员不能参与募资
require(investor != foundationOwner); // 基金会管理员也不行
require(amount > 0);
require(canMint(amount));
mapping(uint => LockBin) locks = lockbins[investor];
LockBin storage info = locks[0];
uint index = info.amount + 1;
locks[index] = LockBin({
start: releaseStart,
finish: releaseStart + releaseDuration,
duration: releaseDuration / (1 days),
amount: amount
});
info.amount = index;
token_created = token_created.add(amount);
wallets[investor] = wallets[investor].add(amount);
emit Mint(investor, amount);
emit Transfer(address(0), investor, amount);
return true;
}
//上面的函数： 就记录了各位什么时间参与的FTN购买记录，
//这个也是保存在以太坊的链上， 解锁周期就是
//每天解锁duration: releaseDuration / (1 days) 这个就记录了周期了
function availableWallet (address user) public view returns (uint256) {
return wallets[user].sub(getLockedToken(user));
}
//这个函数会告诉你，当前用户解锁了多少FTN， 解锁的才是可以交易的
function mint (address target, uint256 amount) public hasMintability whenRunning canForge returns (bool) {
require(target != owner && target != foundationOwner); // Owner和FoundationOwner不能成为mint的对象
require(canMint(amount));
if (msg.sender == foundationOwner) {
require(canMintFoundation(amount));//做增发判断不能超过100亿
token_foundation_created = token_foundation_created.add(amount);
}
token_created = token_created.add(amount);
wallets[target] = wallets[target].add(amount); //FTN进入target这个账户了
emit Mint(target, amount);
emit Transfer(address(0), target, amount);
return true;
}
//上面这个就是我最喜欢的函数了：
//增发函数， 可惜只有管理员有权限
//（发钱的人不能用钱， 用钱的人不能自己增发钱， 所以这个逻辑还是比较合理）
3： 合约安全性分析、
以太坊ICO合约也看了很多， 目前FTN这个合约是我看的比较完整的源码， 从安全上来说， 合约使用SafeMath 库， 同时合约也支持合约的暂停， 退一万步来说， 有一天合约出现了问题， fountain官方也可销毁合约， 最大程解决了安全和利益最大化
4： 合约合理性分析、
1： 合约本身来说是对FTN有总量控制， 那么也就是说fountain 官方不可能无穷无尽的增发， 那么FTN会像比特币一样有价值
2： 白皮书也借鉴了steem的转换机制， 以后FTN会变成FP（合约并未体现）
5：个人对FTN合约分析
FTN 合约很注重细节， 至于为什么， 简单的说说， 合约的逻辑， 增发FTN不能拥有FTN， 交易FTN者不增发FTN
个人比较在意的是： 合约未来的扩展， 一旦合约出现问题， 如何来补丁合约， 还有就是合约的管理员权限过大， 大到瞬间可以成为亿万富豪， 所以fountain的合约管理员至关重要
