// File: contracts/ComptrollerInterface.sol pragma solidity ^0.5.8; interface ComptrollerInterface { /** * @notice Marker function used for light validation when updating the comptroller of a market * @dev Implementations should simply return true. * @return true */ function isComptroller() external view returns (bool); /*** Assets You Are In ***/ function enterMarkets(address[] calldata cTokens) external returns (uint[] memory); function exitMarket(address cToken) external returns (uint); /*** Policy Hooks ***/ function mintAllowed(address cToken, address minter, uint mintAmount) external returns (uint); function mintVerify(address cToken, address minter, uint mintAmount, uint mintTokens) external; function redeemAllowed(address cToken, address redeemer, uint redeemTokens) external returns (uint); function redeemVerify(address cToken, address redeemer, uint redeemAmount, uint redeemTokens) external; function borrowAllowed(address cToken, address borrower, uint borrowAmount) external returns (uint); function borrowVerify(address cToken, address borrower, uint borrowAmount) external; function repayBorrowAllowed( address cToken, address payer, address borrower, uint repayAmount) external returns (uint); function repayBorrowVerify( address cToken, address payer, address borrower, uint repayAmount, uint borrowerIndex) external; function liquidateBorrowAllowed( address cTokenBorrowed, address cTokenCollateral, address liquidator, address borrower, uint repayAmount) external returns (uint); function liquidateBorrowVerify( address cTokenBorrowed, address cTokenCollateral, address liquidator, address borrower, uint repayAmount, uint seizeTokens) external; function seizeAllowed( address cTokenCollateral, address cTokenBorrowed, address liquidator, address borrower, uint seizeTokens) external returns (uint); function seizeVerify( address cTokenCollateral, address cTokenBorrowed, address liquidator, address borrower, uint seizeTokens) external; function transferAllowed(address cToken, address src, address dst, uint transferTokens) external returns (uint); function transferVerify(address cToken, address src, address dst, uint transferTokens) external; /*** Liquidity/Liquidation Calculations ***/ function liquidateCalculateSeizeTokens( address cTokenBorrowed, address cTokenCollateral, uint repayAmount) external view returns (uint, uint); } // File: contracts/ErrorReporter.sol pragma solidity ^0.5.8; contract ComptrollerErrorReporter { enum Error { NO_ERROR, UNAUTHORIZED, COMPTROLLER_MISMATCH, INSUFFICIENT_SHORTFALL, INSUFFICIENT_LIQUIDITY, INVALID_CLOSE_FACTOR, INVALID_COLLATERAL_FACTOR, INVALID_LIQUIDATION_INCENTIVE, MARKET_NOT_ENTERED, MARKET_NOT_LISTED, MARKET_ALREADY_LISTED, MATH_ERROR, NONZERO_BORROW_BALANCE, PRICE_ERROR, REJECTION, SNAPSHOT_ERROR, TOO_MANY_ASSETS, TOO_MUCH_REPAY } enum FailureInfo { ACCEPT_ADMIN_PENDING_ADMIN_CHECK, ACCEPT_PENDING_IMPLEMENTATION_ADDRESS_CHECK, EXIT_MARKET_BALANCE_OWED, EXIT_MARKET_REJECTION, SET_CLOSE_FACTOR_OWNER_CHECK, SET_CLOSE_FACTOR_VALIDATION, SET_COLLATERAL_FACTOR_OWNER_CHECK, SET_COLLATERAL_FACTOR_NO_EXISTS, SET_COLLATERAL_FACTOR_VALIDATION, SET_COLLATERAL_FACTOR_WITHOUT_PRICE, SET_IMPLEMENTATION_OWNER_CHECK, SET_LIQUIDATION_INCENTIVE_OWNER_CHECK, SET_LIQUIDATION_INCENTIVE_VALIDATION, SET_MAX_ASSETS_OWNER_CHECK, SET_PENDING_ADMIN_OWNER_CHECK, SET_PENDING_IMPLEMENTATION_OWNER_CHECK, SET_PRICE_ORACLE_OWNER_CHECK, SUPPORT_MARKET_EXISTS, SUPPORT_MARKET_OWNER_CHECK, ZUNUSED } /** * @dev `error` corresponds to enum Error; `info` corresponds to enum FailureInfo, and `detail` is an arbitrary * contract-specific code that enables us to report opaque error codes from upgradeable contracts. **/ event Failure(uint error, uint info, uint detail); /** * @dev use this when reporting a known error from the money market or a non-upgradeable collaborator */ function fail(Error err, FailureInfo info) internal returns (uint) { emit Failure(uint(err), uint(info), 0); return uint(err); } /** * @dev use this when reporting an opaque error from an upgradeable collaborator contract */ function failOpaque(Error err, FailureInfo info, uint opaqueError) internal returns (uint) { emit Failure(uint(err), uint(info), opaqueError); return uint(err); } } contract TokenErrorReporter { enum Error { NO_ERROR, UNAUTHORIZED, BAD_INPUT, COMPTROLLER_REJECTION, COMPTROLLER_CALCULATION_ERROR, INTEREST_RATE_MODEL_ERROR, INVALID_ACCOUNT_PAIR, INVALID_CLOSE_AMOUNT_REQUESTED, INVALID_COLLATERAL_FACTOR, MATH_ERROR, MARKET_NOT_FRESH, MARKET_NOT_LISTED, TOKEN_INSUFFICIENT_ALLOWANCE, TOKEN_INSUFFICIENT_BALANCE, TOKEN_INSUFFICIENT_CASH, TOKEN_TRANSFER_IN_FAILED, TOKEN_TRANSFER_OUT_FAILED } /* * Note: FailureInfo (but not Error) is kept in alphabetical order * This is because FailureInfo grows significantly faster, and * the order of Error has some meaning, while the order of FailureInfo * is entirely arbitrary. */ enum FailureInfo { ACCEPT_ADMIN_PENDING_ADMIN_CHECK, ACCRUE_INTEREST_ACCUMULATED_INTEREST_CALCULATION_FAILED, ACCRUE_INTEREST_BORROW_RATE_CALCULATION_FAILED, ACCRUE_INTEREST_NEW_BORROW_INDEX_CALCULATION_FAILED, ACCRUE_INTEREST_NEW_TOTAL_BORROWS_CALCULATION_FAILED, ACCRUE_INTEREST_NEW_TOTAL_RESERVES_CALCULATION_FAILED, ACCRUE_INTEREST_SIMPLE_INTEREST_FACTOR_CALCULATION_FAILED, BORROW_ACCUMULATED_BALANCE_CALCULATION_FAILED, BORROW_ACCRUE_INTEREST_FAILED, BORROW_CASH_NOT_AVAILABLE, BORROW_FRESHNESS_CHECK, BORROW_NEW_TOTAL_BALANCE_CALCULATION_FAILED, BORROW_NEW_ACCOUNT_BORROW_BALANCE_CALCULATION_FAILED, BORROW_MARKET_NOT_LISTED, BORROW_COMPTROLLER_REJECTION, LIQUIDATE_ACCRUE_BORROW_INTEREST_FAILED, LIQUIDATE_ACCRUE_COLLATERAL_INTEREST_FAILED, LIQUIDATE_COLLATERAL_FRESHNESS_CHECK, LIQUIDATE_COMPTROLLER_REJECTION, LIQUIDATE_COMPTROLLER_CALCULATE_AMOUNT_SEIZE_FAILED, LIQUIDATE_CLOSE_AMOUNT_IS_UINT_MAX, LIQUIDATE_CLOSE_AMOUNT_IS_ZERO, LIQUIDATE_FRESHNESS_CHECK, LIQUIDATE_LIQUIDATOR_IS_BORROWER, LIQUIDATE_REPAY_BORROW_FRESH_FAILED, LIQUIDATE_SEIZE_BALANCE_INCREMENT_FAILED, LIQUIDATE_SEIZE_BALANCE_DECREMENT_FAILED, LIQUIDATE_SEIZE_COMPTROLLER_REJECTION, LIQUIDATE_SEIZE_LIQUIDATOR_IS_BORROWER, LIQUIDATE_SEIZE_TOO_MUCH, MINT_ACCRUE_INTEREST_FAILED, MINT_COMPTROLLER_REJECTION, MINT_EXCHANGE_CALCULATION_FAILED, MINT_EXCHANGE_RATE_READ_FAILED, MINT_FRESHNESS_CHECK, MINT_NEW_ACCOUNT_BALANCE_CALCULATION_FAILED, MINT_NEW_TOTAL_SUPPLY_CALCULATION_FAILED, MINT_TRANSFER_IN_FAILED, MINT_TRANSFER_IN_NOT_POSSIBLE, REDEEM_ACCRUE_INTEREST_FAILED, REDEEM_COMPTROLLER_REJECTION, REDEEM_EXCHANGE_TOKENS_CALCULATION_FAILED, REDEEM_EXCHANGE_AMOUNT_CALCULATION_FAILED, REDEEM_EXCHANGE_RATE_READ_FAILED, REDEEM_FRESHNESS_CHECK, REDEEM_NEW_ACCOUNT_BALANCE_CALCULATION_FAILED, REDEEM_NEW_TOTAL_SUPPLY_CALCULATION_FAILED, REDEEM_TRANSFER_OUT_NOT_POSSIBLE, REDUCE_RESERVES_ACCRUE_INTEREST_FAILED, REDUCE_RESERVES_ADMIN_CHECK, REDUCE_RESERVES_CASH_NOT_AVAILABLE, REDUCE_RESERVES_FRESH_CHECK, REDUCE_RESERVES_VALIDATION, REPAY_BEHALF_ACCRUE_INTEREST_FAILED, REPAY_BORROW_ACCRUE_INTEREST_FAILED, REPAY_BORROW_ACCUMULATED_BALANCE_CALCULATION_FAILED, REPAY_BORROW_COMPTROLLER_REJECTION, REPAY_BORROW_FRESHNESS_CHECK, REPAY_BORROW_NEW_ACCOUNT_BORROW_BALANCE_CALCULATION_FAILED, REPAY_BORROW_NEW_TOTAL_BALANCE_CALCULATION_FAILED, REPAY_BORROW_TRANSFER_IN_NOT_POSSIBLE, SET_COLLATERAL_FACTOR_OWNER_CHECK, SET_COLLATERAL_FACTOR_VALIDATION, SET_COMPTROLLER_OWNER_CHECK, SET_INTEREST_RATE_MODEL_ACCRUE_INTEREST_FAILED, SET_INTEREST_RATE_MODEL_FRESH_CHECK, SET_INTEREST_RATE_MODEL_OWNER_CHECK, SET_MAX_ASSETS_OWNER_CHECK, SET_ORACLE_MARKET_NOT_LISTED, SET_PENDING_ADMIN_OWNER_CHECK, SET_RESERVE_FACTOR_ACCRUE_INTEREST_FAILED, SET_RESERVE_FACTOR_ADMIN_CHECK, SET_RESERVE_FACTOR_FRESH_CHECK, SET_RESERVE_FACTOR_BOUNDS_CHECK, TRANSFER_COMPTROLLER_REJECTION, TRANSFER_NOT_ALLOWED, TRANSFER_NOT_ENOUGH, TRANSFER_TOO_MUCH } /** * @dev `error` corresponds to enum Error; `info` corresponds to enum FailureInfo, and `detail` is an arbitrary * contract-specific code that enables us to report opaque error codes from upgradeable contracts. **/ event Failure(uint error, uint info, uint detail); /** * @dev use this when reporting a known error from the money market or a non-upgradeable collaborator */ function fail(Error err, FailureInfo info) internal returns (uint) { emit Failure(uint(err), uint(info), 0); return uint(err); } /** * @dev use this when reporting an opaque error from an upgradeable collaborator contract */ function failOpaque(Error err, FailureInfo info, uint opaqueError) internal returns (uint) { emit Failure(uint(err), uint(info), opaqueError); return uint(err); } } // File: contracts/CarefulMath.sol pragma solidity ^0.5.8; /** * @title Careful Math * @author Compound * @notice Derived from OpenZeppelin's SafeMath library * https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/math/SafeMath.sol */ contract CarefulMath { /** * @dev Possible error codes that we can return */ enum MathError { NO_ERROR, DIVISION_BY_ZERO, INTEGER_OVERFLOW, INTEGER_UNDERFLOW } /** * @dev Multiplies two numbers, returns an error on overflow. */ function mulUInt(uint a, uint b) internal pure returns (MathError, uint) { if (a == 0) { return (MathError.NO_ERROR, 0); } uint c = a * b; if (c / a != b) { return (MathError.INTEGER_OVERFLOW, 0); } else { return (MathError.NO_ERROR, c); } } /** * @dev Integer division of two numbers, truncating the quotient. */ function divUInt(uint a, uint b) internal pure returns (MathError, uint) { if (b == 0) { return (MathError.DIVISION_BY_ZERO, 0); } return (MathError.NO_ERROR, a / b); } /** * @dev Subtracts two numbers, returns an error on overflow (i.e. if subtrahend is greater than minuend). */ function subUInt(uint a, uint b) internal pure returns (MathError, uint) { if (b <= a) { return (MathError.NO_ERROR, a - b); } else { return (MathError.INTEGER_UNDERFLOW, 0); } } /** * @dev Adds two numbers, returns an error on overflow. */ function addUInt(uint a, uint b) internal pure returns (MathError, uint) { uint c = a + b; if (c >= a) { return (MathError.NO_ERROR, c); } else { return (MathError.INTEGER_OVERFLOW, 0); } } /** * @dev add a and b and then subtract c */ function addThenSubUInt(uint a, uint b, uint c) internal pure returns (MathError, uint) { (MathError err0, uint sum) = addUInt(a, b); if (err0 != MathError.NO_ERROR) { return (err0, 0); } return subUInt(sum, c); } } // File: contracts/Exponential.sol pragma solidity ^0.5.8; /** * @title Exponential module for storing fixed-decision decimals * @author Compound * @notice Exp is a struct which stores decimals with a fixed precision of 18 decimal places. * Thus, if we wanted to store the 5.1, mantissa would store 5.1e18. That is: * `Exp({mantissa: 5100000000000000000})`. */ contract Exponential is CarefulMath { uint constant expScale = 1e18; uint constant halfExpScale = expScale/2; uint constant mantissaOne = expScale; struct Exp { uint mantissa; } /** * @dev Creates an exponential from numerator and denominator values. * Note: Returns an error if (`num` * 10e18) > MAX_INT, * or if `denom` is zero. */ function getExp(uint num, uint denom) pure internal returns (MathError, Exp memory) { (MathError err0, uint scaledNumerator) = mulUInt(num, expScale); if (err0 != MathError.NO_ERROR) { return (err0, Exp({mantissa: 0})); } (MathError err1, uint rational) = divUInt(scaledNumerator, denom); if (err1 != MathError.NO_ERROR) { return (err1, Exp({mantissa: 0})); } return (MathError.NO_ERROR, Exp({mantissa: rational})); } /** * @dev Adds two exponentials, returning a new exponential. */ function addExp(Exp memory a, Exp memory b) pure internal returns (MathError, Exp memory) { (MathError error, uint result) = addUInt(a.mantissa, b.mantissa); return (error, Exp({mantissa: result})); } /** * @dev Subtracts two exponentials, returning a new exponential. */ function subExp(Exp memory a, Exp memory b) pure internal returns (MathError, Exp memory) { (MathError error, uint result) = subUInt(a.mantissa, b.mantissa); return (error, Exp({mantissa: result})); } /** * @dev Multiply an Exp by a scalar, returning a new Exp. */ function mulScalar(Exp memory a, uint scalar) pure internal returns (MathError, Exp memory) { (MathError err0, uint scaledMantissa) = mulUInt(a.mantissa, scalar); if (err0 != MathError.NO_ERROR) { return (err0, Exp({mantissa: 0})); } return (MathError.NO_ERROR, Exp({mantissa: scaledMantissa})); } /** * @dev Multiply an Exp by a scalar, then truncate to return an unsigned integer. */ function mulScalarTruncate(Exp memory a, uint scalar) pure internal returns (MathError, uint) { (MathError err, Exp memory product) = mulScalar(a, scalar); if (err != MathError.NO_ERROR) { return (err, 0); } return (MathError.NO_ERROR, truncate(product)); } /** * @dev Multiply an Exp by a scalar, truncate, then add an to an unsigned integer, returning an unsigned integer. */ function mulScalarTruncateAddUInt(Exp memory a, uint scalar, uint addend) pure internal returns (MathError, uint) { (MathError err, Exp memory product) = mulScalar(a, scalar); if (err != MathError.NO_ERROR) { return (err, 0); } return addUInt(truncate(product), addend); } /** * @dev Divide an Exp by a scalar, returning a new Exp. */ function divScalar(Exp memory a, uint scalar) pure internal returns (MathError, Exp memory) { (MathError err0, uint descaledMantissa) = divUInt(a.mantissa, scalar); if (err0 != MathError.NO_ERROR) { return (err0, Exp({mantissa: 0})); } return (MathError.NO_ERROR, Exp({mantissa: descaledMantissa})); } /** * @dev Divide a scalar by an Exp, returning a new Exp. */ function divScalarByExp(uint scalar, Exp memory divisor) pure internal returns (MathError, Exp memory) { /* We are doing this as: getExp(mulUInt(expScale, scalar), divisor.mantissa) How it works: Exp = a / b; Scalar = s; `s / (a / b)` = `b * s / a` and since for an Exp `a = mantissa, b = expScale` */ (MathError err0, uint numerator) = mulUInt(expScale, scalar); if (err0 != MathError.NO_ERROR) { return (err0, Exp({mantissa: 0})); } return getExp(numerator, divisor.mantissa); } /** * @dev Divide a scalar by an Exp, then truncate to return an unsigned integer. */ function divScalarByExpTruncate(uint scalar, Exp memory divisor) pure internal returns (MathError, uint) { (MathError err, Exp memory fraction) = divScalarByExp(scalar, divisor); if (err != MathError.NO_ERROR) { return (err, 0); } return (MathError.NO_ERROR, truncate(fraction)); } /** * @dev Multiplies two exponentials, returning a new exponential. */ function mulExp(Exp memory a, Exp memory b) pure internal returns (MathError, Exp memory) { (MathError err0, uint doubleScaledProduct) = mulUInt(a.mantissa, b.mantissa); if (err0 != MathError.NO_ERROR) { return (err0, Exp({mantissa: 0})); } // We add half the scale before dividing so that we get rounding instead of truncation. // See "Listing 6" and text above it at https://accu.org/index.php/journals/1717 // Without this change, a result like 6.6...e-19 will be truncated to 0 instead of being rounded to 1e-18. (MathError err1, uint doubleScaledProductWithHalfScale) = addUInt(halfExpScale, doubleScaledProduct); if (err1 != MathError.NO_ERROR) { return (err1, Exp({mantissa: 0})); } (MathError err2, uint product) = divUInt(doubleScaledProductWithHalfScale, expScale); // The only error `div` can return is MathError.DIVISION_BY_ZERO but we control `expScale` and it is not zero. assert(err2 == MathError.NO_ERROR); return (MathError.NO_ERROR, Exp({mantissa: product})); } /** * @dev Multiplies two exponentials given their mantissas, returning a new exponential. */ function mulExp(uint a, uint b) pure internal returns (MathError, Exp memory) { return mulExp(Exp({mantissa: a}), Exp({mantissa: b})); } /** * @dev Multiplies three exponentials, returning a new exponential. */ function mulExp3(Exp memory a, Exp memory b, Exp memory c) pure internal returns (MathError, Exp memory) { (MathError err, Exp memory ab) = mulExp(a, b); if (err != MathError.NO_ERROR) { return (err, ab); } return mulExp(ab, c); } /** * @dev Divides two exponentials, returning a new exponential. * (a/scale) / (b/scale) = (a/scale) * (scale/b) = a/b, * which we can scale as an Exp by calling getExp(a.mantissa, b.mantissa) */ function divExp(Exp memory a, Exp memory b) pure internal returns (MathError, Exp memory) { return getExp(a.mantissa, b.mantissa); } /** * @dev Truncates the given exp to a whole number value. * For example, truncate(Exp{mantissa: 15 * expScale}) = 15 */ function truncate(Exp memory exp) pure internal returns (uint) { // Note: We are not using careful math here as we're performing a division that cannot fail return exp.mantissa / expScale; } /** * @dev Checks if first Exp is less than second Exp. */ function lessThanExp(Exp memory left, Exp memory right) pure internal returns (bool) { return left.mantissa < right.mantissa; //TODO: Add some simple tests and this in another PR yo. } /** * @dev Checks if left Exp <= right Exp. */ function lessThanOrEqualExp(Exp memory left, Exp memory right) pure internal returns (bool) { return left.mantissa <= right.mantissa; } /** * @dev returns true if Exp is exactly zero */ function isZeroExp(Exp memory value) pure internal returns (bool) { return value.mantissa == 0; } } // File: contracts/EIP20Interface.sol pragma solidity ^0.5.8; /** * @title ERC 20 Token Standard Interface * https://eips.ethereum.org/EIPS/eip-20 */ interface EIP20Interface { /** * @notice Get the total number of tokens in circulation * @return The supply of tokens */ function totalSupply() external view returns (uint256); /** * @notice Gets the balance of the specified address * @param owner The address from which the balance will be retrieved * @return The balance */ function balanceOf(address owner) external view returns (uint256 balance); /** * @notice Transfer `amount` tokens from `msg.sender` to `dst` * @param dst The address of the destination account * @param amount The number of tokens to transfer * @return Whether or not the transfer succeeded */ function transfer(address dst, uint256 amount) external returns (bool success); /** * @notice Transfer `amount` tokens from `src` to `dst` * @param src The address of the source account * @param dst The address of the destination account * @param amount The number of tokens to transfer * @return Whether or not the transfer succeeded */ function transferFrom(address src, address dst, uint256 amount) external returns (bool success); /** * @notice Approve `spender` to transfer up to `amount` from `src` * @dev This will overwrite the approval amount for `spender` * and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve) * @param spender The address of the account which may transfer tokens * @param amount The number of tokens that are approved (-1 means infinite) * @return Whether or not the approval succeeded */ function approve(address spender, uint256 amount) external returns (bool success); /** * @notice Get the current allowance from `owner` for `spender` * @param owner The address of the account which owns the tokens to be spent * @param spender The address of the account which may transfer tokens * @return The number of tokens allowed to be spent (-1 means infinite) */ function allowance(address owner, address spender) external view returns (uint256 remaining); event Transfer(address indexed from, address indexed to, uint256 amount); event Approval(address indexed owner, address indexed spender, uint256 amount); } // File: contracts/EIP20NonStandardInterface.sol pragma solidity ^0.5.8; /** * @title EIP20NonStandardInterface * @dev Version of ERC20 with no return values for `transfer` and `transferFrom` * See https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca */ interface EIP20NonStandardInterface { /** * @notice Get the total number of tokens in circulation * @return The supply of tokens */ function totalSupply() external view returns (uint256); /** * @notice Gets the balance of the specified address * @param owner The address from which the balance will be retrieved * @return The balance */ function balanceOf(address owner) external view returns (uint256 balance); /// /// !!!!!!!!!!!!!! /// !!! NOTICE !!! `transfer` does not return a value, in violation of the ERC-20 specification /// !!!!!!!!!!!!!! /// /** * @notice Transfer `amount` tokens from `msg.sender` to `dst` * @param dst The address of the destination account * @param amount The number of tokens to transfer */ function transfer(address dst, uint256 amount) external; /// /// !!!!!!!!!!!!!! /// !!! NOTICE !!! `transferFrom` does not return a value, in violation of the ERC-20 specification /// !!!!!!!!!!!!!! /// /** * @notice Transfer `amount` tokens from `src` to `dst` * @param src The address of the source account * @param dst The address of the destination account * @param amount The number of tokens to transfer */ function transferFrom(address src, address dst, uint256 amount) external; /** * @notice Approve `spender` to transfer up to `amount` from `src` * @dev This will overwrite the approval amount for `spender` * and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve) * @param spender The address of the account which may transfer tokens * @param amount The number of tokens that are approved * @return Whether or not the approval succeeded */ function approve(address spender, uint256 amount) external returns (bool success); /** * @notice Get the current allowance from `owner` for `spender` * @param owner The address of the account which owns the tokens to be spent * @param spender The address of the account which may transfer tokens * @return The number of tokens allowed to be spent */ function allowance(address owner, address spender) external view returns (uint256 remaining); event Transfer(address indexed from, address indexed to, uint256 amount); event Approval(address indexed owner, address indexed spender, uint256 amount); } // File: contracts/ReentrancyGuard.sol pragma solidity ^0.5.8; /** * @title Helps contracts guard against reentrancy attacks. * @author Remco Bloemen , Eenae * @dev If you mark a function `nonReentrant`, you should also * mark it `external`. */ contract ReentrancyGuard { /// @dev counter to allow mutex lock with only one SSTORE operation uint256 private _guardCounter; constructor () internal { // The counter starts at one to prevent changing it from zero to a non-zero // value, which is a more expensive operation. _guardCounter = 1; } /** * @dev Prevents a contract from calling itself, directly or indirectly. * Calling a `nonReentrant` function from another `nonReentrant` * function is not supported. It is possible to prevent this from happening * by making the `nonReentrant` function external, and make it call a * `private` function that does the actual work. */ modifier nonReentrant() { _guardCounter += 1; uint256 localCounter = _guardCounter; _; require(localCounter == _guardCounter, "re-entered"); } } // File: contracts/InterestRateModel.sol pragma solidity ^0.5.8; /** * @title The Compound InterestRateModel Interface * @author Compound * @notice Any interest rate model should derive from this contract. * @dev These functions are specifically not marked `pure` as implementations of this * contract may read from storage variables. */ interface InterestRateModel { /** * @notice Gets the current borrow interest rate based on the given asset, total cash, total borrows * and total reserves. * @dev The return value should be scaled by 1e18, thus a return value of * `(true, 1000000000000)` implies an interest rate of 0.000001 or 0.0001% *per block*. * @param cash The total cash of the underlying asset in the CToken * @param borrows The total borrows of the underlying asset in the CToken * @param reserves The total reserves of the underlying asset in the CToken * @return Success or failure and the borrow interest rate per block scaled by 10e18 */ function getBorrowRate(uint cash, uint borrows, uint reserves) external view returns (uint, uint); /** * @notice Marker function used for light validation when updating the interest rate model of a market * @dev Marker function used for light validation when updating the interest rate model of a market. Implementations should simply return true. * @return Success or failure */ function isInterestRateModel() external view returns (bool); } // File: contracts/CToken.sol pragma solidity ^0.5.8; /** * @title Compound's CToken Contract * @notice Abstract base for CTokens * @author Compound */ contract CToken is EIP20Interface, Exponential, TokenErrorReporter, ReentrancyGuard { /** * @notice Indicator that this is a CToken contract (for inspection) */ bool public constant isCToken = true; /** * @notice EIP-20 token name for this token */ string public name; /** * @notice EIP-20 token symbol for this token */ string public symbol; /** * @notice EIP-20 token decimals for this token */ uint public decimals; /** * @notice Maximum borrow rate that can ever be applied (.0005% / block) */ uint constant borrowRateMaxMantissa = 5e14; /** * @notice Maximum fraction of interest that can be set aside for reserves */ uint constant reserveFactorMaxMantissa = 1e18; /** * @notice Administrator for this contract */ address payable public admin; /** * @notice Pending administrator for this contract */ address payable public pendingAdmin; /** * @notice Contract which oversees inter-cToken operations */ ComptrollerInterface public comptroller; /** * @notice Model which tells what the current interest rate should be */ InterestRateModel public interestRateModel; /** * @notice Initial exchange rate used when minting the first CTokens (used when totalSupply = 0) */ uint public initialExchangeRateMantissa; /** * @notice Fraction of interest currently set aside for reserves */ uint public reserveFactorMantissa; /** * @notice Block number that interest was last accrued at */ uint public accrualBlockNumber; /** * @notice Accumulator of total earned interest since the opening of the market */ uint public borrowIndex; /** * @notice Total amount of outstanding borrows of the underlying in this market */ uint public totalBorrows; /** * @notice Total amount of reserves of the underlying held in this market */ uint public totalReserves; /** * @notice Total number of tokens in circulation */ uint256 public totalSupply; /** * @notice Official record of token balances for each account */ mapping (address => uint256) accountTokens; /** * @notice Approved token transfer amounts on behalf of others */ mapping (address => mapping (address => uint256)) transferAllowances; /** * @notice Container for borrow balance information * @member principal Total balance (with accrued interest), after applying the most recent balance-changing action * @member interestIndex Global borrowIndex as of the most recent balance-changing action */ struct BorrowSnapshot { uint principal; uint interestIndex; } /** * @notice Mapping of account addresses to outstanding borrow balances */ mapping(address => BorrowSnapshot) accountBorrows; /*** Market Events ***/ /** * @notice Event emitted when interest is accrued */ event AccrueInterest(uint interestAccumulated, uint borrowIndex, uint totalBorrows); /** * @notice Event emitted when tokens are minted */ event Mint(address minter, uint mintAmount, uint mintTokens); /** * @notice Event emitted when tokens are redeemed */ event Redeem(address redeemer, uint redeemAmount, uint redeemTokens); /** * @notice Event emitted when underlying is borrowed */ event Borrow(address borrower, uint borrowAmount, uint accountBorrows, uint totalBorrows); /** * @notice Event emitted when a borrow is repaid */ event RepayBorrow(address payer, address borrower, uint repayAmount, uint accountBorrows, uint totalBorrows); /** * @notice Event emitted when a borrow is liquidated */ event LiquidateBorrow(address liquidator, address borrower, uint repayAmount, address cTokenCollateral, uint seizeTokens); /*** Admin Events ***/ /** * @notice Event emitted when pendingAdmin is changed */ event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin); /** * @notice Event emitted when pendingAdmin is accepted, which means admin is updated */ event NewAdmin(address oldAdmin, address newAdmin); /** * @notice Event emitted when comptroller is changed */ event NewComptroller(ComptrollerInterface oldComptroller, ComptrollerInterface newComptroller); /** * @notice Event emitted when interestRateModel is changed */ event NewMarketInterestRateModel(InterestRateModel oldInterestRateModel, InterestRateModel newInterestRateModel); /** * @notice Event emitted when the reserve factor is changed */ event NewReserveFactor(uint oldReserveFactorMantissa, uint newReserveFactorMantissa); /** * @notice Event emitted when the reserves are reduced */ event ReservesReduced(address admin, uint reduceAmount, uint newTotalReserves); /** * @notice Construct a new money market * @param comptroller_ The address of the Comptroller * @param interestRateModel_ The address of the interest rate model * @param initialExchangeRateMantissa_ The initial exchange rate, scaled by 1e18 * @param name_ EIP-20 name of this token * @param symbol_ EIP-20 symbol of this token * @param decimals_ EIP-20 decimal precision of this token */ constructor(ComptrollerInterface comptroller_, InterestRateModel interestRateModel_, uint initialExchangeRateMantissa_, string memory name_, string memory symbol_, uint decimals_) internal { // Set admin to msg.sender admin = msg.sender; // Set initial exchange rate initialExchangeRateMantissa = initialExchangeRateMantissa_; require(initialExchangeRateMantissa > 0, "Initial exchange rate must be greater than zero."); // Set the comptroller uint err = _setComptroller(comptroller_); require(err == uint(Error.NO_ERROR), "Setting comptroller failed"); // Initialize block number and borrow index (block number mocks depend on comptroller being set) accrualBlockNumber = getBlockNumber(); borrowIndex = mantissaOne; // Set the interest rate model (depends on block number / borrow index) err = _setInterestRateModelFresh(interestRateModel_); require(err == uint(Error.NO_ERROR), "Setting interest rate model failed"); name = name_; symbol = symbol_; decimals = decimals_; } /** * @notice Transfer `tokens` tokens from `src` to `dst` by `spender` * @dev Called by both `transfer` and `transferFrom` internally * @param spender The address of the account performing the transfer * @param src The address of the source account * @param dst The address of the destination account * @param tokens The number of tokens to transfer * @return Whether or not the transfer succeeded */ function transferTokens(address spender, address src, address dst, uint tokens) internal returns (uint) { /* Fail if transfer not allowed */ uint allowed = comptroller.transferAllowed(address(this), src, dst, tokens); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.TRANSFER_COMPTROLLER_REJECTION, allowed); } /* Do not allow self-transfers */ if (src == dst) { return fail(Error.BAD_INPUT, FailureInfo.TRANSFER_NOT_ALLOWED); } /* Get the allowance, infinite for the account owner */ uint startingAllowance = 0; if (spender == src) { startingAllowance = uint(-1); } else { startingAllowance = transferAllowances[src][spender]; } /* Do the calculations, checking for {under,over}flow */ MathError mathErr; uint allowanceNew; uint srcTokensNew; uint dstTokensNew; (mathErr, allowanceNew) = subUInt(startingAllowance, tokens); if (mathErr != MathError.NO_ERROR) { return fail(Error.MATH_ERROR, FailureInfo.TRANSFER_NOT_ALLOWED); } (mathErr, srcTokensNew) = subUInt(accountTokens[src], tokens); if (mathErr != MathError.NO_ERROR) { return fail(Error.MATH_ERROR, FailureInfo.TRANSFER_NOT_ENOUGH); } (mathErr, dstTokensNew) = addUInt(accountTokens[dst], tokens); if (mathErr != MathError.NO_ERROR) { return fail(Error.MATH_ERROR, FailureInfo.TRANSFER_TOO_MUCH); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) accountTokens[src] = srcTokensNew; accountTokens[dst] = dstTokensNew; /* Eat some of the allowance (if necessary) */ if (startingAllowance != uint(-1)) { transferAllowances[src][spender] = allowanceNew; } /* We emit a Transfer event */ emit Transfer(src, dst, tokens); /* We call the defense hook (which checks for under-collateralization) */ comptroller.transferVerify(address(this), src, dst, tokens); return uint(Error.NO_ERROR); } /** * @notice Transfer `amount` tokens from `msg.sender` to `dst` * @param dst The address of the destination account * @param amount The number of tokens to transfer * @return Whether or not the transfer succeeded */ function transfer(address dst, uint256 amount) external nonReentrant returns (bool) { return transferTokens(msg.sender, msg.sender, dst, amount) == uint(Error.NO_ERROR); } /** * @notice Transfer `amount` tokens from `src` to `dst` * @param src The address of the source account * @param dst The address of the destination account * @param amount The number of tokens to transfer * @return Whether or not the transfer succeeded */ function transferFrom(address src, address dst, uint256 amount) external nonReentrant returns (bool) { return transferTokens(msg.sender, src, dst, amount) == uint(Error.NO_ERROR); } /** * @notice Approve `spender` to transfer up to `amount` from `src` * @dev This will overwrite the approval amount for `spender` * and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve) * @param spender The address of the account which may transfer tokens * @param amount The number of tokens that are approved (-1 means infinite) * @return Whether or not the approval succeeded */ function approve(address spender, uint256 amount) external returns (bool) { address src = msg.sender; transferAllowances[src][spender] = amount; emit Approval(src, spender, amount); return true; } /** * @notice Get the current allowance from `owner` for `spender` * @param owner The address of the account which owns the tokens to be spent * @param spender The address of the account which may transfer tokens * @return The number of tokens allowed to be spent (-1 means infinite) */ function allowance(address owner, address spender) external view returns (uint256) { return transferAllowances[owner][spender]; } /** * @notice Get the token balance of the `owner` * @param owner The address of the account to query * @return The number of tokens owned by `owner` */ function balanceOf(address owner) external view returns (uint256) { return accountTokens[owner]; } /** * @notice Get the underlying balance of the `owner` * @dev This also accrues interest in a transaction * @param owner The address of the account to query * @return The amount of underlying owned by `owner` */ function balanceOfUnderlying(address owner) external returns (uint) { Exp memory exchangeRate = Exp({mantissa: exchangeRateCurrent()}); (MathError mErr, uint balance) = mulScalarTruncate(exchangeRate, accountTokens[owner]); require(mErr == MathError.NO_ERROR); return balance; } /** * @notice Get a snapshot of the account's balances, and the cached exchange rate * @dev This is used by comptroller to more efficiently perform liquidity checks. * @param account Address of the account to snapshot * @return (possible error, token balance, borrow balance, exchange rate mantissa) */ function getAccountSnapshot(address account) external view returns (uint, uint, uint, uint) { uint cTokenBalance = accountTokens[account]; uint borrowBalance; uint exchangeRateMantissa; MathError mErr; (mErr, borrowBalance) = borrowBalanceStoredInternal(account); if (mErr != MathError.NO_ERROR) { return (uint(Error.MATH_ERROR), 0, 0, 0); } (mErr, exchangeRateMantissa) = exchangeRateStoredInternal(); if (mErr != MathError.NO_ERROR) { return (uint(Error.MATH_ERROR), 0, 0, 0); } return (uint(Error.NO_ERROR), cTokenBalance, borrowBalance, exchangeRateMantissa); } /** * @dev Function to simply retrieve block number * This exists mainly for inheriting test contracts to stub this result. */ function getBlockNumber() internal view returns (uint) { return block.number; } /** * @notice Returns the current per-block borrow interest rate for this cToken * @return The borrow interest rate per block, scaled by 1e18 */ function borrowRatePerBlock() external view returns (uint) { (uint opaqueErr, uint borrowRateMantissa) = interestRateModel.getBorrowRate(getCashPrior(), totalBorrows, totalReserves); require(opaqueErr == 0, "borrowRatePerBlock: interestRateModel.borrowRate failed"); // semi-opaque return borrowRateMantissa; } /** * @notice Returns the current per-block supply interest rate for this cToken * @return The supply interest rate per block, scaled by 1e18 */ function supplyRatePerBlock() external view returns (uint) { /* We calculate the supply rate: * underlying = totalSupply × exchangeRate * borrowsPer = totalBorrows ÷ underlying * supplyRate = borrowRate × (1-reserveFactor) × borrowsPer */ uint exchangeRateMantissa = exchangeRateStored(); (uint e0, uint borrowRateMantissa) = interestRateModel.getBorrowRate(getCashPrior(), totalBorrows, totalReserves); require(e0 == 0, "supplyRatePerBlock: calculating borrowRate failed"); // semi-opaque (MathError e1, Exp memory underlying) = mulScalar(Exp({mantissa: exchangeRateMantissa}), totalSupply); require(e1 == MathError.NO_ERROR, "supplyRatePerBlock: calculating underlying failed"); (MathError e2, Exp memory borrowsPer) = divScalarByExp(totalBorrows, underlying); require(e2 == MathError.NO_ERROR, "supplyRatePerBlock: calculating borrowsPer failed"); (MathError e3, Exp memory oneMinusReserveFactor) = subExp(Exp({mantissa: mantissaOne}), Exp({mantissa: reserveFactorMantissa})); require(e3 == MathError.NO_ERROR, "supplyRatePerBlock: calculating oneMinusReserveFactor failed"); (MathError e4, Exp memory supplyRate) = mulExp3(Exp({mantissa: borrowRateMantissa}), oneMinusReserveFactor, borrowsPer); require(e4 == MathError.NO_ERROR, "supplyRatePerBlock: calculating supplyRate failed"); return supplyRate.mantissa; } /** * @notice Returns the current total borrows plus accrued interest * @return The total borrows with interest */ function totalBorrowsCurrent() external nonReentrant returns (uint) { require(accrueInterest() == uint(Error.NO_ERROR), "accrue interest failed"); return totalBorrows; } /** * @notice Accrue interest to updated borrowIndex and then calculate account's borrow balance using the updated borrowIndex * @param account The address whose balance should be calculated after updating borrowIndex * @return The calculated balance */ function borrowBalanceCurrent(address account) external nonReentrant returns (uint) { require(accrueInterest() == uint(Error.NO_ERROR), "accrue interest failed"); return borrowBalanceStored(account); } /** * @notice Return the borrow balance of account based on stored data * @param account The address whose balance should be calculated * @return The calculated balance */ function borrowBalanceStored(address account) public view returns (uint) { (MathError err, uint result) = borrowBalanceStoredInternal(account); require(err == MathError.NO_ERROR, "borrowBalanceStored: borrowBalanceStoredInternal failed"); return result; } /** * @notice Return the borrow balance of account based on stored data * @param account The address whose balance should be calculated * @return (error code, the calculated balance or 0 if error code is non-zero) */ function borrowBalanceStoredInternal(address account) internal view returns (MathError, uint) { /* Note: we do not assert that the market is up to date */ MathError mathErr; uint principalTimesIndex; uint result; /* Get borrowBalance and borrowIndex */ BorrowSnapshot storage borrowSnapshot = accountBorrows[account]; /* If borrowBalance = 0 then borrowIndex is likely also 0. * Rather than failing the calculation with a division by 0, we immediately return 0 in this case. */ if (borrowSnapshot.principal == 0) { return (MathError.NO_ERROR, 0); } /* Calculate new borrow balance using the interest index: * recentBorrowBalance = borrower.borrowBalance * market.borrowIndex / borrower.borrowIndex */ (mathErr, principalTimesIndex) = mulUInt(borrowSnapshot.principal, borrowIndex); if (mathErr != MathError.NO_ERROR) { return (mathErr, 0); } (mathErr, result) = divUInt(principalTimesIndex, borrowSnapshot.interestIndex); if (mathErr != MathError.NO_ERROR) { return (mathErr, 0); } return (MathError.NO_ERROR, result); } /** * @notice Accrue interest then return the up-to-date exchange rate * @return Calculated exchange rate scaled by 1e18 */ function exchangeRateCurrent() public nonReentrant returns (uint) { require(accrueInterest() == uint(Error.NO_ERROR), "accrue interest failed"); return exchangeRateStored(); } /** * @notice Calculates the exchange rate from the underlying to the CToken * @dev This function does not accrue interest before calculating the exchange rate * @return Calculated exchange rate scaled by 1e18 */ function exchangeRateStored() public view returns (uint) { (MathError err, uint result) = exchangeRateStoredInternal(); require(err == MathError.NO_ERROR, "exchangeRateStored: exchangeRateStoredInternal failed"); return result; } /** * @notice Calculates the exchange rate from the underlying to the CToken * @dev This function does not accrue interest before calculating the exchange rate * @return (error code, calculated exchange rate scaled by 1e18) */ function exchangeRateStoredInternal() internal view returns (MathError, uint) { if (totalSupply == 0) { /* * If there are no tokens minted: * exchangeRate = initialExchangeRate */ return (MathError.NO_ERROR, initialExchangeRateMantissa); } else { /* * Otherwise: * exchangeRate = (totalCash + totalBorrows - totalReserves) / totalSupply */ uint totalCash = getCashPrior(); uint cashPlusBorrowsMinusReserves; Exp memory exchangeRate; MathError mathErr; (mathErr, cashPlusBorrowsMinusReserves) = addThenSubUInt(totalCash, totalBorrows, totalReserves); if (mathErr != MathError.NO_ERROR) { return (mathErr, 0); } (mathErr, exchangeRate) = getExp(cashPlusBorrowsMinusReserves, totalSupply); if (mathErr != MathError.NO_ERROR) { return (mathErr, 0); } return (MathError.NO_ERROR, exchangeRate.mantissa); } } /** * @notice Get cash balance of this cToken in the underlying asset * @return The quantity of underlying asset owned by this contract */ function getCash() external view returns (uint) { return getCashPrior(); } struct AccrueInterestLocalVars { MathError mathErr; uint opaqueErr; uint borrowRateMantissa; uint currentBlockNumber; uint blockDelta; Exp simpleInterestFactor; uint interestAccumulated; uint totalBorrowsNew; uint totalReservesNew; uint borrowIndexNew; } /** * @notice Applies accrued interest to total borrows and reserves. * @dev This calculates interest accrued from the last checkpointed block * up to the current block and writes new checkpoint to storage. */ function accrueInterest() public returns (uint) { AccrueInterestLocalVars memory vars; /* Calculate the current borrow interest rate */ (vars.opaqueErr, vars.borrowRateMantissa) = interestRateModel.getBorrowRate(getCashPrior(), totalBorrows, totalReserves); require(vars.borrowRateMantissa <= borrowRateMaxMantissa, "borrow rate is absurdly high"); if (vars.opaqueErr != 0) { return failOpaque(Error.INTEREST_RATE_MODEL_ERROR, FailureInfo.ACCRUE_INTEREST_BORROW_RATE_CALCULATION_FAILED, vars.opaqueErr); } /* Remember the initial block number */ vars.currentBlockNumber = getBlockNumber(); /* Calculate the number of blocks elapsed since the last accrual */ (vars.mathErr, vars.blockDelta) = subUInt(vars.currentBlockNumber, accrualBlockNumber); assert(vars.mathErr == MathError.NO_ERROR); // Block delta should always succeed and if it doesn't, blow up. /* * Calculate the interest accumulated into borrows and reserves and the new index: * simpleInterestFactor = borrowRate * blockDelta * interestAccumulated = simpleInterestFactor * totalBorrows * totalBorrowsNew = interestAccumulated + totalBorrows * totalReservesNew = interestAccumulated * reserveFactor + totalReserves * borrowIndexNew = simpleInterestFactor * borrowIndex + borrowIndex */ (vars.mathErr, vars.simpleInterestFactor) = mulScalar(Exp({mantissa: vars.borrowRateMantissa}), vars.blockDelta); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.ACCRUE_INTEREST_SIMPLE_INTEREST_FACTOR_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.interestAccumulated) = mulScalarTruncate(vars.simpleInterestFactor, totalBorrows); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.ACCRUE_INTEREST_ACCUMULATED_INTEREST_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.totalBorrowsNew) = addUInt(vars.interestAccumulated, totalBorrows); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.ACCRUE_INTEREST_NEW_TOTAL_BORROWS_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.totalReservesNew) = mulScalarTruncateAddUInt(Exp({mantissa: reserveFactorMantissa}), vars.interestAccumulated, totalReserves); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.ACCRUE_INTEREST_NEW_TOTAL_RESERVES_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.borrowIndexNew) = mulScalarTruncateAddUInt(vars.simpleInterestFactor, borrowIndex, borrowIndex); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.ACCRUE_INTEREST_NEW_BORROW_INDEX_CALCULATION_FAILED, uint(vars.mathErr)); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* We write the previously calculated values into storage */ accrualBlockNumber = vars.currentBlockNumber; borrowIndex = vars.borrowIndexNew; totalBorrows = vars.totalBorrowsNew; totalReserves = vars.totalReservesNew; /* We emit an AccrueInterest event */ emit AccrueInterest(vars.interestAccumulated, vars.borrowIndexNew, totalBorrows); return uint(Error.NO_ERROR); } /** * @notice Sender supplies assets into the market and receives cTokens in exchange * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param mintAmount The amount of the underlying asset to supply * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function mintInternal(uint mintAmount) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted borrow failed return fail(Error(error), FailureInfo.MINT_ACCRUE_INTEREST_FAILED); } // mintFresh emits the actual Mint event if successful and logs on errors, so we don't need to return mintFresh(msg.sender, mintAmount); } struct MintLocalVars { Error err; MathError mathErr; uint exchangeRateMantissa; uint mintTokens; uint totalSupplyNew; uint accountTokensNew; } /** * @notice User supplies assets into the market and receives cTokens in exchange * @dev Assumes interest has already been accrued up to the current block * @param minter The address of the account which is supplying the assets * @param mintAmount The amount of the underlying asset to supply * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function mintFresh(address minter, uint mintAmount) internal returns (uint) { /* Fail if mint not allowed */ uint allowed = comptroller.mintAllowed(address(this), minter, mintAmount); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.MINT_COMPTROLLER_REJECTION, allowed); } /* Verify market's block number equals current block number */ if (accrualBlockNumber != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.MINT_FRESHNESS_CHECK); } MintLocalVars memory vars; /* Fail if checkTransferIn fails */ vars.err = checkTransferIn(minter, mintAmount); if (vars.err != Error.NO_ERROR) { return fail(vars.err, FailureInfo.MINT_TRANSFER_IN_NOT_POSSIBLE); } /* * We get the current exchange rate and calculate the number of cTokens to be minted: * mintTokens = mintAmount / exchangeRate */ (vars.mathErr, vars.exchangeRateMantissa) = exchangeRateStoredInternal(); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.MINT_EXCHANGE_RATE_READ_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.mintTokens) = divScalarByExpTruncate(mintAmount, Exp({mantissa: vars.exchangeRateMantissa})); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.MINT_EXCHANGE_CALCULATION_FAILED, uint(vars.mathErr)); } /* * We calculate the new total supply of cTokens and minter token balance, checking for overflow: * totalSupplyNew = totalSupply + mintTokens * accountTokensNew = accountTokens[minter] + mintTokens */ (vars.mathErr, vars.totalSupplyNew) = addUInt(totalSupply, vars.mintTokens); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.MINT_NEW_TOTAL_SUPPLY_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.accountTokensNew) = addUInt(accountTokens[minter], vars.mintTokens); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.MINT_NEW_ACCOUNT_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* * We call doTransferIn for the minter and the mintAmount * Note: The cToken must handle variations between ERC-20 and ETH underlying. * On success, the cToken holds an additional mintAmount of cash. * If doTransferIn fails despite the fact we checked pre-conditions, * we revert because we can't be sure if side effects occurred. */ vars.err = doTransferIn(minter, mintAmount); if (vars.err != Error.NO_ERROR) { return fail(vars.err, FailureInfo.MINT_TRANSFER_IN_FAILED); } /* We write previously calculated values into storage */ totalSupply = vars.totalSupplyNew; accountTokens[minter] = vars.accountTokensNew; /* We emit a Mint event, and a Transfer event */ emit Mint(minter, mintAmount, vars.mintTokens); emit Transfer(address(this), minter, vars.mintTokens); /* We call the defense hook */ comptroller.mintVerify(address(this), minter, mintAmount, vars.mintTokens); return uint(Error.NO_ERROR); } /** * @notice Sender redeems cTokens in exchange for the underlying asset * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param redeemTokens The number of cTokens to redeem into underlying * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function redeemInternal(uint redeemTokens) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted redeem failed return fail(Error(error), FailureInfo.REDEEM_ACCRUE_INTEREST_FAILED); } // redeemFresh emits redeem-specific logs on errors, so we don't need to return redeemFresh(msg.sender, redeemTokens, 0); } /** * @notice Sender redeems cTokens in exchange for a specified amount of underlying asset * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param redeemAmount The amount of underlying to redeem * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function redeemUnderlyingInternal(uint redeemAmount) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted redeem failed return fail(Error(error), FailureInfo.REDEEM_ACCRUE_INTEREST_FAILED); } // redeemFresh emits redeem-specific logs on errors, so we don't need to return redeemFresh(msg.sender, 0, redeemAmount); } struct RedeemLocalVars { Error err; MathError mathErr; uint exchangeRateMantissa; uint redeemTokens; uint redeemAmount; uint totalSupplyNew; uint accountTokensNew; } /** * @notice User redeems cTokens in exchange for the underlying asset * @dev Assumes interest has already been accrued up to the current block * @param redeemer The address of the account which is redeeming the tokens * @param redeemTokensIn The number of cTokens to redeem into underlying (only one of redeemTokensIn or redeemAmountIn may be zero) * @param redeemAmountIn The number of cTokens to redeem into underlying (only one of redeemTokensIn or redeemAmountIn may be zero) * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function redeemFresh(address payable redeemer, uint redeemTokensIn, uint redeemAmountIn) internal returns (uint) { require(redeemTokensIn == 0 || redeemAmountIn == 0, "one of redeemTokensIn or redeemAmountIn must be zero"); RedeemLocalVars memory vars; /* exchangeRate = invoke Exchange Rate Stored() */ (vars.mathErr, vars.exchangeRateMantissa) = exchangeRateStoredInternal(); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REDEEM_EXCHANGE_RATE_READ_FAILED, uint(vars.mathErr)); } /* If redeemTokensIn > 0: */ if (redeemTokensIn > 0) { /* * We calculate the exchange rate and the amount of underlying to be redeemed: * redeemTokens = redeemTokensIn * redeemAmount = redeemTokensIn x exchangeRateCurrent */ vars.redeemTokens = redeemTokensIn; (vars.mathErr, vars.redeemAmount) = mulScalarTruncate(Exp({mantissa: vars.exchangeRateMantissa}), redeemTokensIn); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REDEEM_EXCHANGE_TOKENS_CALCULATION_FAILED, uint(vars.mathErr)); } } else { /* * We get the current exchange rate and calculate the amount to be redeemed: * redeemTokens = redeemAmountIn / exchangeRate * redeemAmount = redeemAmountIn */ (vars.mathErr, vars.redeemTokens) = divScalarByExpTruncate(redeemAmountIn, Exp({mantissa: vars.exchangeRateMantissa})); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REDEEM_EXCHANGE_AMOUNT_CALCULATION_FAILED, uint(vars.mathErr)); } vars.redeemAmount = redeemAmountIn; } /* Fail if redeem not allowed */ uint allowed = comptroller.redeemAllowed(address(this), redeemer, vars.redeemTokens); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.REDEEM_COMPTROLLER_REJECTION, allowed); } /* Verify market's block number equals current block number */ if (accrualBlockNumber != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.REDEEM_FRESHNESS_CHECK); } /* * We calculate the new total supply and redeemer balance, checking for underflow: * totalSupplyNew = totalSupply - redeemTokens * accountTokensNew = accountTokens[redeemer] - redeemTokens */ (vars.mathErr, vars.totalSupplyNew) = subUInt(totalSupply, vars.redeemTokens); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REDEEM_NEW_TOTAL_SUPPLY_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.accountTokensNew) = subUInt(accountTokens[redeemer], vars.redeemTokens); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REDEEM_NEW_ACCOUNT_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } /* Fail gracefully if protocol has insufficient cash */ if (getCashPrior() < vars.redeemAmount) { return fail(Error.TOKEN_INSUFFICIENT_CASH, FailureInfo.REDEEM_TRANSFER_OUT_NOT_POSSIBLE); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* * We invoke doTransferOut for the redeemer and the redeemAmount. * Note: The cToken must handle variations between ERC-20 and ETH underlying. * On success, the cToken has redeemAmount less of cash. * If doTransferOut fails despite the fact we checked pre-conditions, * we revert because we can't be sure if side effects occurred. */ vars.err = doTransferOut(redeemer, vars.redeemAmount); require(vars.err == Error.NO_ERROR, "redeem transfer out failed"); /* We write previously calculated values into storage */ totalSupply = vars.totalSupplyNew; accountTokens[redeemer] = vars.accountTokensNew; /* We emit a Transfer event, and a Redeem event */ emit Transfer(redeemer, address(this), vars.redeemTokens); emit Redeem(redeemer, vars.redeemAmount, vars.redeemTokens); /* We call the defense hook */ comptroller.redeemVerify(address(this), redeemer, vars.redeemAmount, vars.redeemTokens); return uint(Error.NO_ERROR); } /** * @notice Sender borrows assets from the protocol to their own address * @param borrowAmount The amount of the underlying asset to borrow * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function borrowInternal(uint borrowAmount) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted borrow failed return fail(Error(error), FailureInfo.BORROW_ACCRUE_INTEREST_FAILED); } // borrowFresh emits borrow-specific logs on errors, so we don't need to return borrowFresh(msg.sender, borrowAmount); } struct BorrowLocalVars { Error err; MathError mathErr; uint accountBorrows; uint accountBorrowsNew; uint totalBorrowsNew; } /** * @notice Users borrow assets from the protocol to their own address * @param borrowAmount The amount of the underlying asset to borrow * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function borrowFresh(address payable borrower, uint borrowAmount) internal returns (uint) { /* Fail if borrow not allowed */ uint allowed = comptroller.borrowAllowed(address(this), borrower, borrowAmount); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.BORROW_COMPTROLLER_REJECTION, allowed); } /* Verify market's block number equals current block number */ if (accrualBlockNumber != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.BORROW_FRESHNESS_CHECK); } /* Fail gracefully if protocol has insufficient underlying cash */ if (getCashPrior() < borrowAmount) { return fail(Error.TOKEN_INSUFFICIENT_CASH, FailureInfo.BORROW_CASH_NOT_AVAILABLE); } BorrowLocalVars memory vars; /* * We calculate the new borrower and total borrow balances, failing on overflow: * accountBorrowsNew = accountBorrows + borrowAmount * totalBorrowsNew = totalBorrows + borrowAmount */ (vars.mathErr, vars.accountBorrows) = borrowBalanceStoredInternal(borrower); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.BORROW_ACCUMULATED_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.accountBorrowsNew) = addUInt(vars.accountBorrows, borrowAmount); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.BORROW_NEW_ACCOUNT_BORROW_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.totalBorrowsNew) = addUInt(totalBorrows, borrowAmount); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.BORROW_NEW_TOTAL_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* * We invoke doTransferOut for the borrower and the borrowAmount. * Note: The cToken must handle variations between ERC-20 and ETH underlying. * On success, the cToken borrowAmount less of cash. * If doTransferOut fails despite the fact we checked pre-conditions, * we revert because we can't be sure if side effects occurred. */ vars.err = doTransferOut(borrower, borrowAmount); require(vars.err == Error.NO_ERROR, "borrow transfer out failed"); /* We write the previously calculated values into storage */ accountBorrows[borrower].principal = vars.accountBorrowsNew; accountBorrows[borrower].interestIndex = borrowIndex; totalBorrows = vars.totalBorrowsNew; /* We emit a Borrow event */ emit Borrow(borrower, borrowAmount, vars.accountBorrowsNew, vars.totalBorrowsNew); /* We call the defense hook */ comptroller.borrowVerify(address(this), borrower, borrowAmount); return uint(Error.NO_ERROR); } /** * @notice Sender repays their own borrow * @param repayAmount The amount to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function repayBorrowInternal(uint repayAmount) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted borrow failed return fail(Error(error), FailureInfo.REPAY_BORROW_ACCRUE_INTEREST_FAILED); } // repayBorrowFresh emits repay-borrow-specific logs on errors, so we don't need to return repayBorrowFresh(msg.sender, msg.sender, repayAmount); } /** * @notice Sender repays a borrow belonging to borrower * @param borrower the account with the debt being payed off * @param repayAmount The amount to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function repayBorrowBehalfInternal(address borrower, uint repayAmount) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted borrow failed return fail(Error(error), FailureInfo.REPAY_BEHALF_ACCRUE_INTEREST_FAILED); } // repayBorrowFresh emits repay-borrow-specific logs on errors, so we don't need to return repayBorrowFresh(msg.sender, borrower, repayAmount); } struct RepayBorrowLocalVars { Error err; MathError mathErr; uint repayAmount; uint borrowerIndex; uint accountBorrows; uint accountBorrowsNew; uint totalBorrowsNew; } /** * @notice Borrows are repaid by another user (possibly the borrower). * @param payer the account paying off the borrow * @param borrower the account with the debt being payed off * @param repayAmount the amount of undelrying tokens being returned * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function repayBorrowFresh(address payer, address borrower, uint repayAmount) internal returns (uint) { /* Fail if repayBorrow not allowed */ uint allowed = comptroller.repayBorrowAllowed(address(this), payer, borrower, repayAmount); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.REPAY_BORROW_COMPTROLLER_REJECTION, allowed); } /* Verify market's block number equals current block number */ if (accrualBlockNumber != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.REPAY_BORROW_FRESHNESS_CHECK); } RepayBorrowLocalVars memory vars; /* We remember the original borrowerIndex for verification purposes */ vars.borrowerIndex = accountBorrows[borrower].interestIndex; /* We fetch the amount the borrower owes, with accumulated interest */ (vars.mathErr, vars.accountBorrows) = borrowBalanceStoredInternal(borrower); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REPAY_BORROW_ACCUMULATED_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } /* If repayAmount == -1, repayAmount = accountBorrows */ if (repayAmount == uint(-1)) { vars.repayAmount = vars.accountBorrows; } else { vars.repayAmount = repayAmount; } /* Fail if checkTransferIn fails */ vars.err = checkTransferIn(payer, vars.repayAmount); if (vars.err != Error.NO_ERROR) { return fail(vars.err, FailureInfo.REPAY_BORROW_TRANSFER_IN_NOT_POSSIBLE); } /* * We calculate the new borrower and total borrow balances, failing on underflow: * accountBorrowsNew = accountBorrows - repayAmount * totalBorrowsNew = totalBorrows - repayAmount */ (vars.mathErr, vars.accountBorrowsNew) = subUInt(vars.accountBorrows, vars.repayAmount); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REPAY_BORROW_NEW_ACCOUNT_BORROW_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } (vars.mathErr, vars.totalBorrowsNew) = subUInt(totalBorrows, vars.repayAmount); if (vars.mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.REPAY_BORROW_NEW_TOTAL_BALANCE_CALCULATION_FAILED, uint(vars.mathErr)); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* * We call doTransferIn for the payer and the repayAmount * Note: The cToken must handle variations between ERC-20 and ETH underlying. * On success, the cToken holds an additional repayAmount of cash. * If doTransferIn fails despite the fact we checked pre-conditions, * we revert because we can't be sure if side effects occurred. */ vars.err = doTransferIn(payer, vars.repayAmount); require(vars.err == Error.NO_ERROR, "repay borrow transfer in failed"); /* We write the previously calculated values into storage */ accountBorrows[borrower].principal = vars.accountBorrowsNew; accountBorrows[borrower].interestIndex = borrowIndex; totalBorrows = vars.totalBorrowsNew; /* We emit a RepayBorrow event */ emit RepayBorrow(payer, borrower, vars.repayAmount, vars.accountBorrowsNew, vars.totalBorrowsNew); /* We call the defense hook */ comptroller.repayBorrowVerify(address(this), payer, borrower, vars.repayAmount, vars.borrowerIndex); return uint(Error.NO_ERROR); } /** * @notice The sender liquidates the borrowers collateral. * The collateral seized is transferred to the liquidator. * @param borrower The borrower of this cToken to be liquidated * @param cTokenCollateral The market in which to seize collateral from the borrower * @param repayAmount The amount of the underlying borrowed asset to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function liquidateBorrowInternal(address borrower, uint repayAmount, CToken cTokenCollateral) internal nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted liquidation failed return fail(Error(error), FailureInfo.LIQUIDATE_ACCRUE_BORROW_INTEREST_FAILED); } error = cTokenCollateral.accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but we still want to log the fact that an attempted liquidation failed return fail(Error(error), FailureInfo.LIQUIDATE_ACCRUE_COLLATERAL_INTEREST_FAILED); } // liquidateBorrowFresh emits borrow-specific logs on errors, so we don't need to return liquidateBorrowFresh(msg.sender, borrower, repayAmount, cTokenCollateral); } /** * @notice The liquidator liquidates the borrowers collateral. * The collateral seized is transferred to the liquidator. * @param borrower The borrower of this cToken to be liquidated * @param liquidator The address repaying the borrow and seizing collateral * @param cTokenCollateral The market in which to seize collateral from the borrower * @param repayAmount The amount of the underlying borrowed asset to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function liquidateBorrowFresh(address liquidator, address borrower, uint repayAmount, CToken cTokenCollateral) internal returns (uint) { /* Fail if liquidate not allowed */ uint allowed = comptroller.liquidateBorrowAllowed(address(this), address(cTokenCollateral), liquidator, borrower, repayAmount); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.LIQUIDATE_COMPTROLLER_REJECTION, allowed); } /* Verify market's block number equals current block number */ if (accrualBlockNumber != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.LIQUIDATE_FRESHNESS_CHECK); } /* Verify cTokenCollateral market's block number equals current block number */ if (cTokenCollateral.accrualBlockNumber() != getBlockNumber()) { return fail(Error.MARKET_NOT_FRESH, FailureInfo.LIQUIDATE_COLLATERAL_FRESHNESS_CHECK); } /* Fail if borrower = liquidator */ if (borrower == liquidator) { return fail(Error.INVALID_ACCOUNT_PAIR, FailureInfo.LIQUIDATE_LIQUIDATOR_IS_BORROWER); } /* Fail if repayAmount = 0 */ if (repayAmount == 0) { return fail(Error.INVALID_CLOSE_AMOUNT_REQUESTED, FailureInfo.LIQUIDATE_CLOSE_AMOUNT_IS_ZERO); } /* Fail if repayAmount = -1 */ if (repayAmount == uint(-1)) { return fail(Error.INVALID_CLOSE_AMOUNT_REQUESTED, FailureInfo.LIQUIDATE_CLOSE_AMOUNT_IS_UINT_MAX); } /* We calculate the number of collateral tokens that will be seized */ (uint amountSeizeError, uint seizeTokens) = comptroller.liquidateCalculateSeizeTokens(address(this), address(cTokenCollateral), repayAmount); if (amountSeizeError != 0) { return failOpaque(Error.COMPTROLLER_CALCULATION_ERROR, FailureInfo.LIQUIDATE_COMPTROLLER_CALCULATE_AMOUNT_SEIZE_FAILED, amountSeizeError); } /* Fail if seizeTokens > borrower collateral token balance */ if (seizeTokens > cTokenCollateral.balanceOf(borrower)) { return fail(Error.TOKEN_INSUFFICIENT_BALANCE, FailureInfo.LIQUIDATE_SEIZE_TOO_MUCH); } /* Fail if repayBorrow fails */ uint repayBorrowError = repayBorrowFresh(liquidator, borrower, repayAmount); if (repayBorrowError != uint(Error.NO_ERROR)) { return fail(Error(repayBorrowError), FailureInfo.LIQUIDATE_REPAY_BORROW_FRESH_FAILED); } /* Revert if seize tokens fails (since we cannot be sure of side effects) */ uint seizeError = cTokenCollateral.seize(liquidator, borrower, seizeTokens); require(seizeError == uint(Error.NO_ERROR), "token seizure failed"); /* We emit a LiquidateBorrow event */ emit LiquidateBorrow(liquidator, borrower, repayAmount, address(cTokenCollateral), seizeTokens); /* We call the defense hook */ comptroller.liquidateBorrowVerify(address(this), address(cTokenCollateral), liquidator, borrower, repayAmount, seizeTokens); return uint(Error.NO_ERROR); } /** * @notice Transfers collateral tokens (this market) to the liquidator. * @dev Will fail unless called by another cToken during the process of liquidation. * Its absolutely critical to use msg.sender as the borrowed cToken and not a parameter. * @param liquidator The account receiving seized collateral * @param borrower The account having collateral seized * @param seizeTokens The number of cTokens to seize * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function seize(address liquidator, address borrower, uint seizeTokens) external nonReentrant returns (uint) { /* Fail if seize not allowed */ uint allowed = comptroller.seizeAllowed(address(this), msg.sender, liquidator, borrower, seizeTokens); if (allowed != 0) { return failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.LIQUIDATE_SEIZE_COMPTROLLER_REJECTION, allowed); } /* Fail if borrower = liquidator */ if (borrower == liquidator) { return fail(Error.INVALID_ACCOUNT_PAIR, FailureInfo.LIQUIDATE_SEIZE_LIQUIDATOR_IS_BORROWER); } MathError mathErr; uint borrowerTokensNew; uint liquidatorTokensNew; /* * We calculate the new borrower and liquidator token balances, failing on underflow/overflow: * borrowerTokensNew = accountTokens[borrower] - seizeTokens * liquidatorTokensNew = accountTokens[liquidator] + seizeTokens */ (mathErr, borrowerTokensNew) = subUInt(accountTokens[borrower], seizeTokens); if (mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.LIQUIDATE_SEIZE_BALANCE_DECREMENT_FAILED, uint(mathErr)); } (mathErr, liquidatorTokensNew) = addUInt(accountTokens[liquidator], seizeTokens); if (mathErr != MathError.NO_ERROR) { return failOpaque(Error.MATH_ERROR, FailureInfo.LIQUIDATE_SEIZE_BALANCE_INCREMENT_FAILED, uint(mathErr)); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) /* We write the previously calculated values into storage */ accountTokens[borrower] = borrowerTokensNew; accountTokens[liquidator] = liquidatorTokensNew; /* Emit a Transfer event */ emit Transfer(borrower, liquidator, seizeTokens); /* We call the defense hook */ comptroller.seizeVerify(address(this), msg.sender, liquidator, borrower, seizeTokens); return uint(Error.NO_ERROR); } /*** Admin Functions ***/ /** * @notice Begins transfer of admin rights. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer. * @dev Admin function to begin change of admin. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer. * @param newPendingAdmin New pending admin. * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) * * TODO: Should we add a second arg to verify, like a checksum of `newAdmin` address? */ function _setPendingAdmin(address payable newPendingAdmin) external returns (uint) { // Check caller = admin if (msg.sender != admin) { return fail(Error.UNAUTHORIZED, FailureInfo.SET_PENDING_ADMIN_OWNER_CHECK); } // Save current value, if any, for inclusion in log address oldPendingAdmin = pendingAdmin; // Store pendingAdmin with value newPendingAdmin pendingAdmin = newPendingAdmin; // Emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin) emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin); return uint(Error.NO_ERROR); } /** * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin * @dev Admin function for pending admin to accept role and update admin * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _acceptAdmin() external returns (uint) { // Check caller is pendingAdmin and pendingAdmin ≠ address(0) if (msg.sender != pendingAdmin || msg.sender == address(0)) { return fail(Error.UNAUTHORIZED, FailureInfo.ACCEPT_ADMIN_PENDING_ADMIN_CHECK); } // Save current values for inclusion in log address oldAdmin = admin; address oldPendingAdmin = pendingAdmin; // Store admin with value pendingAdmin admin = pendingAdmin; // Clear the pending value pendingAdmin = address(0); emit NewAdmin(oldAdmin, admin); emit NewPendingAdmin(oldPendingAdmin, pendingAdmin); return uint(Error.NO_ERROR); } /** * @notice Sets a new comptroller for the market * @dev Admin function to set a new comptroller * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _setComptroller(ComptrollerInterface newComptroller) public returns (uint) { // Check caller is admin if (msg.sender != admin) { return fail(Error.UNAUTHORIZED, FailureInfo.SET_COMPTROLLER_OWNER_CHECK); } ComptrollerInterface oldComptroller = comptroller; // Ensure invoke comptroller.isComptroller() returns true require(newComptroller.isComptroller(), "marker method returned false"); // Set market's comptroller to newComptroller comptroller = newComptroller; // Emit NewComptroller(oldComptroller, newComptroller) emit NewComptroller(oldComptroller, newComptroller); return uint(Error.NO_ERROR); } /** * @notice accrues interest and sets a new reserve factor for the protocol using _setReserveFactorFresh * @dev Admin function to accrue interest and set a new reserve factor * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _setReserveFactor(uint newReserveFactorMantissa) external nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but on top of that we want to log the fact that an attempted reserve factor change failed. return fail(Error(error), FailureInfo.SET_RESERVE_FACTOR_ACCRUE_INTEREST_FAILED); } // _setReserveFactorFresh emits reserve-factor-specific logs on errors, so we don't need to. return _setReserveFactorFresh(newReserveFactorMantissa); } /** * @notice Sets a new reserve factor for the protocol (*requires fresh interest accrual) * @dev Admin function to set a new reserve factor * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _setReserveFactorFresh(uint newReserveFactorMantissa) internal returns (uint) { // Check caller is admin if (msg.sender != admin) { return fail(Error.UNAUTHORIZED, FailureInfo.SET_RESERVE_FACTOR_ADMIN_CHECK); } // Verify market's block number equals current block number if (accrualBlockNumber != getBlockNumber()) { // TODO: static_assert + no error code? return fail(Error.MARKET_NOT_FRESH, FailureInfo.SET_RESERVE_FACTOR_FRESH_CHECK); } // Check newReserveFactor ≤ maxReserveFactor if (newReserveFactorMantissa > reserveFactorMaxMantissa) { return fail(Error.BAD_INPUT, FailureInfo.SET_RESERVE_FACTOR_BOUNDS_CHECK); } uint oldReserveFactorMantissa = reserveFactorMantissa; reserveFactorMantissa = newReserveFactorMantissa; emit NewReserveFactor(oldReserveFactorMantissa, newReserveFactorMantissa); return uint(Error.NO_ERROR); } /** * @notice Accrues interest and reduces reserves by transferring to admin * @param reduceAmount Amount of reduction to reserves * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _reduceReserves(uint reduceAmount) external nonReentrant returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but on top of that we want to log the fact that an attempted reduce reserves failed. return fail(Error(error), FailureInfo.REDUCE_RESERVES_ACCRUE_INTEREST_FAILED); } // _reduceReservesFresh emits reserve-reduction-specific logs on errors, so we don't need to. return _reduceReservesFresh(reduceAmount); } /** * @notice Reduces reserves by transferring to admin * @dev Requires fresh interest accrual * @param reduceAmount Amount of reduction to reserves * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _reduceReservesFresh(uint reduceAmount) internal returns (uint) { Error err; // totalReserves - reduceAmount uint totalReservesNew; // Check caller is admin if (msg.sender != admin) { return fail(Error.UNAUTHORIZED, FailureInfo.REDUCE_RESERVES_ADMIN_CHECK); } // We fail gracefully unless market's block number equals current block number if (accrualBlockNumber != getBlockNumber()) { // TODO: static_assert + no error code? return fail(Error.MARKET_NOT_FRESH, FailureInfo.REDUCE_RESERVES_FRESH_CHECK); } // Fail gracefully if protocol has insufficient underlying cash if (getCashPrior() < reduceAmount) { return fail(Error.TOKEN_INSUFFICIENT_CASH, FailureInfo.REDUCE_RESERVES_CASH_NOT_AVAILABLE); } // Check reduceAmount ≤ reserves[n] (totalReserves) // TODO: I'm following the spec literally here but I think we should we just use SafeMath instead and fail on an error (which would be underflow) if (reduceAmount > totalReserves) { return fail(Error.BAD_INPUT, FailureInfo.REDUCE_RESERVES_VALIDATION); } ///////////////////////// // EFFECTS & INTERACTIONS // (No safe failures beyond this point) totalReservesNew = totalReserves - reduceAmount; // We checked reduceAmount <= totalReserves above, so this should never revert. require(totalReservesNew <= totalReserves, "reduce reserves unexpected underflow"); // Store reserves[n+1] = reserves[n] - reduceAmount totalReserves = totalReservesNew; // invoke doTransferOut(reduceAmount, admin) err = doTransferOut(admin, reduceAmount); // we revert on the failure of this command require(err == Error.NO_ERROR, "reduce reserves transfer out failed"); emit ReservesReduced(admin, reduceAmount, totalReservesNew); return uint(Error.NO_ERROR); } /** * @notice accrues interest and updates the interest rate model using _setInterestRateModelFresh * @dev Admin function to accrue interest and update the interest rate model * @param newInterestRateModel the new interest rate model to use * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _setInterestRateModel(InterestRateModel newInterestRateModel) public returns (uint) { uint error = accrueInterest(); if (error != uint(Error.NO_ERROR)) { // accrueInterest emits logs on errors, but on top of that we want to log the fact that an attempted change of interest rate model failed return fail(Error(error), FailureInfo.SET_INTEREST_RATE_MODEL_ACCRUE_INTEREST_FAILED); } // _setInterestRateModelFresh emits interest-rate-model-update-specific logs on errors, so we don't need to. return _setInterestRateModelFresh(newInterestRateModel); } /** * @notice updates the interest rate model (*requires fresh interest accrual) * @dev Admin function to update the interest rate model * @param newInterestRateModel the new interest rate model to use * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function _setInterestRateModelFresh(InterestRateModel newInterestRateModel) internal returns (uint) { // Used to store old model for use in the event that is emitted on success InterestRateModel oldInterestRateModel; // Check caller is admin if (msg.sender != admin) { return fail(Error.UNAUTHORIZED, FailureInfo.SET_INTEREST_RATE_MODEL_OWNER_CHECK); } // We fail gracefully unless market's block number equals current block number if (accrualBlockNumber != getBlockNumber()) { // TODO: static_assert + no error code? return fail(Error.MARKET_NOT_FRESH, FailureInfo.SET_INTEREST_RATE_MODEL_FRESH_CHECK); } // Track the market's current interest rate model oldInterestRateModel = interestRateModel; // Ensure invoke newInterestRateModel.isInterestRateModel() returns true require(newInterestRateModel.isInterestRateModel(), "marker method returned false"); // Set the interest rate model to newInterestRateModel interestRateModel = newInterestRateModel; // Emit NewMarketInterestRateModel(oldInterestRateModel, newInterestRateModel) emit NewMarketInterestRateModel(oldInterestRateModel, newInterestRateModel); return uint(Error.NO_ERROR); } /*** Safe Token ***/ /** * @notice Gets balance of this contract in terms of the underlying * @dev This excludes the value of the current message, if any * @return The quantity of underlying owned by this contract */ function getCashPrior() internal view returns (uint); /** * @dev Checks whether or not there is sufficient allowance for this contract to move amount from `from` and * whether or not `from` has a balance of at least `amount`. Does NOT do a transfer. */ function checkTransferIn(address from, uint amount) internal view returns (Error); /** * @dev Performs a transfer in, ideally returning an explanatory error code upon failure rather than reverting. * If caller has not called `checkTransferIn`, this may revert due to insufficient balance or insufficient allowance. * If caller has called `checkTransferIn` successfully, this should not revert in normal conditions. */ function doTransferIn(address from, uint amount) internal returns (Error); /** * @dev Performs a transfer out, ideally returning an explanatory error code upon failure tather than reverting. * If caller has not called checked protocol's balance, may revert due to insufficient cash held in the contract. * If caller has checked protocol's balance, and verified it is >= amount, this should not revert in normal conditions. */ function doTransferOut(address payable to, uint amount) internal returns (Error); } // File: contracts/CErc20.sol pragma solidity ^0.5.8; /** * @title Compound's CErc20 Contract * @notice CTokens which wrap an EIP-20 underlying * @author Compound */ contract CErc20 is CToken { /** * @notice Underlying asset for this CToken */ address public underlying; /** * @notice Construct a new money market * @param underlying_ The address of the underlying asset * @param comptroller_ The address of the Comptroller * @param interestRateModel_ The address of the interest rate model * @param initialExchangeRateMantissa_ The initial exchange rate, scaled by 1e18 * @param name_ ERC-20 name of this token * @param symbol_ ERC-20 symbol of this token * @param decimals_ ERC-20 decimal precision of this token */ constructor(address underlying_, ComptrollerInterface comptroller_, InterestRateModel interestRateModel_, uint initialExchangeRateMantissa_, string memory name_, string memory symbol_, uint decimals_) public CToken(comptroller_, interestRateModel_, initialExchangeRateMantissa_, name_, symbol_, decimals_) { // Set underlying underlying = underlying_; EIP20Interface(underlying).totalSupply(); // Sanity check the underlying } /*** User Interface ***/ /** * @notice Sender supplies assets into the market and receives cTokens in exchange * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param mintAmount The amount of the underlying asset to supply * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function mint(uint mintAmount) external returns (uint) { return mintInternal(mintAmount); } /** * @notice Sender redeems cTokens in exchange for the underlying asset * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param redeemTokens The number of cTokens to redeem into underlying * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function redeem(uint redeemTokens) external returns (uint) { return redeemInternal(redeemTokens); } /** * @notice Sender redeems cTokens in exchange for a specified amount of underlying asset * @dev Accrues interest whether or not the operation succeeds, unless reverted * @param redeemAmount The amount of underlying to redeem * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function redeemUnderlying(uint redeemAmount) external returns (uint) { return redeemUnderlyingInternal(redeemAmount); } /** * @notice Sender borrows assets from the protocol to their own address * @param borrowAmount The amount of the underlying asset to borrow * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function borrow(uint borrowAmount) external returns (uint) { return borrowInternal(borrowAmount); } /** * @notice Sender repays their own borrow * @param repayAmount The amount to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function repayBorrow(uint repayAmount) external returns (uint) { return repayBorrowInternal(repayAmount); } /** * @notice Sender repays a borrow belonging to borrower * @param borrower the account with the debt being payed off * @param repayAmount The amount to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function repayBorrowBehalf(address borrower, uint repayAmount) external returns (uint) { return repayBorrowBehalfInternal(borrower, repayAmount); } /** * @notice The sender liquidates the borrowers collateral. * The collateral seized is transferred to the liquidator. * @param borrower The borrower of this cToken to be liquidated * @param cTokenCollateral The market in which to seize collateral from the borrower * @param repayAmount The amount of the underlying borrowed asset to repay * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details) */ function liquidateBorrow(address borrower, uint repayAmount, CToken cTokenCollateral) external returns (uint) { return liquidateBorrowInternal(borrower, repayAmount, cTokenCollateral); } /*** Safe Token ***/ /** * @notice Gets balance of this contract in terms of the underlying * @dev This excludes the value of the current message, if any * @return The quantity of underlying tokens owned by this contract */ function getCashPrior() internal view returns (uint) { EIP20Interface token = EIP20Interface(underlying); return token.balanceOf(address(this)); } /** * @dev Checks whether or not there is sufficient allowance for this contract to move amount from `from` and * whether or not `from` has a balance of at least `amount`. Does NOT do a transfer. */ function checkTransferIn(address from, uint amount) internal view returns (Error) { EIP20Interface token = EIP20Interface(underlying); if (token.allowance(from, address(this)) < amount) { return Error.TOKEN_INSUFFICIENT_ALLOWANCE; } if (token.balanceOf(from) < amount) { return Error.TOKEN_INSUFFICIENT_BALANCE; } return Error.NO_ERROR; } /** * @dev Similar to EIP20 transfer, except it handles a False result from `transferFrom` and returns an explanatory * error code rather than reverting. If caller has not called `checkTransferIn`, this may revert due to * insufficient balance or insufficient allowance. If caller has called `checkTransferIn` prior to this call, * and it returned Error.NO_ERROR, this should not revert in normal conditions. * * Note: This wrapper safely handles non-standard ERC-20 tokens that do not return a value. * See here: https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca */ function doTransferIn(address from, uint amount) internal returns (Error) { EIP20NonStandardInterface token = EIP20NonStandardInterface(underlying); bool result; token.transferFrom(from, address(this), amount); // solium-disable-next-line security/no-inline-assembly assembly { switch returndatasize() case 0 { // This is a non-standard ERC-20 result := not(0) // set result to true } case 32 { // This is a complaint ERC-20 returndatacopy(0, 0, 32) result := mload(0) // Set `result = returndata` of external call } default { // This is an excessively non-compliant ERC-20, revert. revert(0, 0) } } if (!result) { return Error.TOKEN_TRANSFER_IN_FAILED; } return Error.NO_ERROR; } /** * @dev Similar to EIP20 transfer, except it handles a False result from `transfer` and returns an explanatory * error code rather than reverting. If caller has not called checked protocol's balance, this may revert due to * insufficient cash held in this contract. If caller has checked protocol's balance prior to this call, and verified * it is >= amount, this should not revert in normal conditions. * * Note: This wrapper safely handles non-standard ERC-20 tokens that do not return a value. * See here: https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca */ function doTransferOut(address payable to, uint amount) internal returns (Error) { EIP20NonStandardInterface token = EIP20NonStandardInterface(underlying); bool result; token.transfer(to, amount); // solium-disable-next-line security/no-inline-assembly assembly { switch returndatasize() case 0 { // This is a non-standard ERC-20 result := not(0) // set result to true } case 32 { // This is a complaint ERC-20 returndatacopy(0, 0, 32) result := mload(0) // Set `result = returndata` of external call } default { // This is an excessively non-compliant ERC-20, revert. revert(0, 0) } } if (!result) { return Error.TOKEN_TRANSFER_OUT_FAILED; } return Error.NO_ERROR; } }

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