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Copy pathComptroller.sol
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Comptroller.sol
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pragma solidity ^0.5.16;
import "./CToken.sol";
import "./ErrorReporter.sol";
import "./PriceOracle.sol";
import "./ComptrollerInterface.sol";
import "./ComptrollerStorage.sol";
import "./Unitroller.sol";
import "./Governance/Comp.sol";
import "./EIP20Interface.sol";
/**
* @title Compound's Comptroller Contract
* @author Compound
*/
contract Comptroller is ComptrollerV5Storage, ComptrollerInterface, ComptrollerErrorReporter, ExponentialNoError {
/// @notice Emitted when an admin supports a market
event MarketListed(CToken cToken);
/// @notice Emitted when an account enters a market
event MarketEntered(CToken cToken, address account);
/// @notice Emitted when an account exits a market
event MarketExited(CToken cToken, address account);
/// @notice Emitted when close factor is changed by admin
event NewCloseFactor(uint oldCloseFactorMantissa, uint newCloseFactorMantissa);
/// @notice Emitted when a collateral factor is changed by admin
event NewCollateralFactor(CToken cToken, uint oldCollateralFactorMantissa, uint newCollateralFactorMantissa);
/// @notice Emitted when liquidation incentive is changed by admin
event NewLiquidationIncentive(uint oldLiquidationIncentiveMantissa, uint newLiquidationIncentiveMantissa);
/// @notice Emitted when price oracle is changed
event NewPriceOracle(PriceOracle oldPriceOracle, PriceOracle newPriceOracle);
/// @notice Emitted when pause guardian is changed
event NewPauseGuardian(address oldPauseGuardian, address newPauseGuardian);
/// @notice Emitted when an action is paused globally
event ActionPaused(string action, bool pauseState);
/// @notice Emitted when an action is paused on a market
event ActionPaused(CToken cToken, string action, bool pauseState);
/// @notice Emitted when a new COMP speed is calculated for a market
event CompSpeedUpdated(CToken indexed cToken, uint newSpeed);
/// @notice Emitted when a new COMP speed is set for a contributor
event ContributorCompSpeedUpdated(address indexed contributor, uint newSpeed);
/// @notice Emitted when COMP is distributed to a supplier
event DistributedSupplierComp(CToken indexed cToken, address indexed supplier, uint compDelta, uint compSupplyIndex);
/// @notice Emitted when COMP is distributed to a borrower
event DistributedBorrowerComp(CToken indexed cToken, address indexed borrower, uint compDelta, uint compBorrowIndex);
/// @notice Emitted when borrow cap for a cToken is changed
event NewBorrowCap(CToken indexed cToken, uint newBorrowCap);
/// @notice Emitted when borrow cap guardian is changed
event NewBorrowCapGuardian(address oldBorrowCapGuardian, address newBorrowCapGuardian);
/// @notice Emitted when COMP is granted by admin
event CompGranted(address recipient, uint amount);
event LiquidatorWhiteListOnUpdated(bool isOn);
event LiquidatorAdded(address indexed liquidator);
event LiquidatorRemoved(address indexed liquidator);
/// @notice The initial COMP index for a market
uint224 public constant compInitialIndex = 1e36;
// closeFactorMantissa must be strictly greater than this value
uint internal constant closeFactorMinMantissa = 0.05e18; // 0.05
// closeFactorMantissa must not exceed this value
uint internal constant closeFactorMaxMantissa = 0.9e18; // 0.9
// No collateralFactorMantissa may exceed this value
uint internal constant collateralFactorMaxMantissa = 0.9e18; // 0.9
constructor() public {
admin = msg.sender;
liquidatorWhiteListOn = false;
}
/*** Assets You Are In ***/
/**
* @notice Returns the assets an account has entered
* @param account The address of the account to pull assets for
* @return A dynamic list with the assets the account has entered
*/
function getAssetsIn(address account) external view returns (CToken[] memory) {
CToken[] memory assetsIn = accountAssets[account];
return assetsIn;
}
/**
* @notice Returns whether the given account is entered in the given asset
* @param account The address of the account to check
* @param cToken The cToken to check
* @return True if the account is in the asset, otherwise false.
*/
function checkMembership(address account, CToken cToken) external view returns (bool) {
return markets[address(cToken)].accountMembership[account];
}
/**
* @notice Add assets to be included in account liquidity calculation
* @param cTokens The list of addresses of the cToken markets to be enabled
* @return Success indicator for whether each corresponding market was entered
*/
function enterMarkets(address[] memory cTokens) public returns (uint[] memory) {
uint len = cTokens.length;
uint[] memory results = new uint[](len);
for (uint i = 0; i < len; i++) {
CToken cToken = CToken(cTokens[i]);
results[i] = uint(addToMarketInternal(cToken, msg.sender));
}
return results;
}
/**
* @notice Add the market to the borrower's "assets in" for liquidity calculations
* @param cToken The market to enter
* @param borrower The address of the account to modify
* @return Success indicator for whether the market was entered
*/
function addToMarketInternal(CToken cToken, address borrower) internal returns (Error) {
Market storage marketToJoin = markets[address(cToken)];
if (!marketToJoin.isListed) {
// market is not listed, cannot join
return Error.MARKET_NOT_LISTED;
}
if (marketToJoin.accountMembership[borrower] == true) {
// already joined
return Error.NO_ERROR;
}
// survived the gauntlet, add to list
// NOTE: we store these somewhat redundantly as a significant optimization
// this avoids having to iterate through the list for the most common use cases
// that is, only when we need to perform liquidity checks
// and not whenever we want to check if an account is in a particular market
marketToJoin.accountMembership[borrower] = true;
accountAssets[borrower].push(cToken);
emit MarketEntered(cToken, borrower);
return Error.NO_ERROR;
}
/**
* @notice Removes asset from sender's account liquidity calculation
* @dev Sender must not have an outstanding borrow balance in the asset,
* or be providing necessary collateral for an outstanding borrow.
* @param cTokenAddress The address of the asset to be removed
* @return Whether or not the account successfully exited the market
*/
function exitMarket(address cTokenAddress) external returns (uint) {
CToken cToken = CToken(cTokenAddress);
/* Get sender tokensHeld and amountOwed underlying from the cToken */
(uint oErr, uint tokensHeld, uint amountOwed, ) = cToken.getAccountSnapshot(msg.sender);
require(oErr == 0, "exitMarket: getAccountSnapshot failed"); // semi-opaque error code
/* Fail if the sender has a borrow balance */
if (amountOwed != 0) {
return fail(Error.NONZERO_BORROW_BALANCE, FailureInfo.EXIT_MARKET_BALANCE_OWED);
}
/* Fail if the sender is not permitted to redeem all of their tokens */
uint allowed = redeemAllowedInternal(cTokenAddress, msg.sender, tokensHeld);
if (allowed != 0) {
return failOpaque(Error.REJECTION, FailureInfo.EXIT_MARKET_REJECTION, allowed);
}
Market storage marketToExit = markets[address(cToken)];
/* Return true if the sender is not already ‘in’ the market */
if (!marketToExit.accountMembership[msg.sender]) {
return uint(Error.NO_ERROR);
}
/* Set cToken account membership to false */
delete marketToExit.accountMembership[msg.sender];
/* Delete cToken from the account’s list of assets */
// load into memory for faster iteration
CToken[] memory userAssetList = accountAssets[msg.sender];
uint len = userAssetList.length;
uint assetIndex = len;
for (uint i = 0; i < len; i++) {
if (userAssetList[i] == cToken) {
assetIndex = i;
break;
}
}
// We *must* have found the asset in the list or our redundant data structure is broken
assert(assetIndex < len);
// copy last item in list to location of item to be removed, reduce length by 1
CToken[] storage storedList = accountAssets[msg.sender];
storedList[assetIndex] = storedList[storedList.length - 1];
storedList.length--;
emit MarketExited(cToken, msg.sender);
return uint(Error.NO_ERROR);
}
/*** Policy Hooks ***/
/**
* @notice Checks if the account should be allowed to mint tokens in the given market
* @param cToken The market to verify the mint against
* @param minter The account which would get the minted tokens
* @param mintAmount The amount of underlying being supplied to the market in exchange for tokens
* @return 0 if the mint is allowed, otherwise a semi-opaque error code (See ErrorReporter.sol)
*/
function mintAllowed(address cToken, address minter, uint mintAmount) external returns (uint) {
// Pausing is a very serious situation - we revert to sound the alarms
require(!mintGuardianPaused[cToken], "mint is paused");
// Shh - currently unused
minter;
mintAmount;
if (!markets[cToken].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
// Keep the flywheel moving
updateCompSupplyIndex(cToken);
distributeSupplierComp(cToken, minter);
return uint(Error.NO_ERROR);
}
/**
* @notice Validates mint and reverts on rejection. May emit logs.
* @param cToken Asset being minted
* @param minter The address minting the tokens
* @param actualMintAmount The amount of the underlying asset being minted
* @param mintTokens The number of tokens being minted
*/
// function mintVerify(address cToken, address minter, uint actualMintAmount, uint mintTokens) external {
// // // Shh - currently unused
// // cToken;
// // minter;
// // actualMintAmount;
// // mintTokens;
// // // Shh - we don't ever want this hook to be marked pure
// // if (false) {
// // maxAssets = maxAssets;
// // }
// }
/**
* @notice Checks if the account should be allowed to redeem tokens in the given market
* @param cToken The market to verify the redeem against
* @param redeemer The account which would redeem the tokens
* @param redeemTokens The number of cTokens to exchange for the underlying asset in the market
* @return 0 if the redeem is allowed, otherwise a semi-opaque error code (See ErrorReporter.sol)
*/
function redeemAllowed(address cToken, address redeemer, uint redeemTokens) external returns (uint) {
uint allowed = redeemAllowedInternal(cToken, redeemer, redeemTokens);
if (allowed != uint(Error.NO_ERROR)) {
return allowed;
}
// Keep the flywheel moving
updateCompSupplyIndex(cToken);
distributeSupplierComp(cToken, redeemer);
return uint(Error.NO_ERROR);
}
function redeemAllowedInternal(address cToken, address redeemer, uint redeemTokens) internal view returns (uint) {
if (!markets[cToken].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
/* If the redeemer is not 'in' the market, then we can bypass the liquidity check */
if (!markets[cToken].accountMembership[redeemer]) {
return uint(Error.NO_ERROR);
}
/* Otherwise, perform a hypothetical liquidity check to guard against shortfall */
(Error err, , uint shortfall) = getHypotheticalAccountLiquidityInternal(redeemer, CToken(cToken), redeemTokens, 0);
if (err != Error.NO_ERROR) {
return uint(err);
}
if (shortfall > 0) {
return uint(Error.INSUFFICIENT_LIQUIDITY);
}
return uint(Error.NO_ERROR);
}
/**
* @notice Validates redeem and reverts on rejection. May emit logs.
* @param cToken Asset being redeemed
* @param redeemer The address redeeming the tokens
* @param redeemAmount The amount of the underlying asset being redeemed
* @param redeemTokens The number of tokens being redeemed
*/
// function redeemVerify(address cToken, address redeemer, uint redeemAmount, uint redeemTokens) external {
// // // Shh - currently unused
// // cToken;
// // redeemer;
// // // Require tokens is zero or amount is also zero
// // if (redeemTokens == 0 && redeemAmount > 0) {
// // revert("redeemTokens zero");
// // }
// }
/**
* @notice Checks if the account should be allowed to borrow the underlying asset of the given market
* @param cToken The market to verify the borrow against
* @param borrower The account which would borrow the asset
* @param borrowAmount The amount of underlying the account would borrow
* @return 0 if the borrow is allowed, otherwise a semi-opaque error code (See ErrorReporter.sol)
*/
function borrowAllowed(address cToken, address borrower, uint borrowAmount) external returns (uint) {
// Pausing is a very serious situation - we revert to sound the alarms
require(!borrowGuardianPaused[cToken], "borrow is paused");
if (!markets[cToken].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
if (!markets[cToken].accountMembership[borrower]) {
// only cTokens may call borrowAllowed if borrower not in market
require(msg.sender == cToken, "sender must be cToken");
// attempt to add borrower to the market
Error err = addToMarketInternal(CToken(msg.sender), borrower);
if (err != Error.NO_ERROR) {
return uint(err);
}
// it should be impossible to break the important invariant
assert(markets[cToken].accountMembership[borrower]);
}
if (oracle.getUnderlyingPrice(CToken(cToken)) == 0) {
return uint(Error.PRICE_ERROR);
}
uint borrowCap = borrowCaps[cToken];
// Borrow cap of 0 corresponds to unlimited borrowing
if (borrowCap != 0) {
uint totalBorrows = CToken(cToken).totalBorrows();
uint nextTotalBorrows = add_(totalBorrows, borrowAmount);
require(nextTotalBorrows < borrowCap, "market borrow cap reached");
}
(Error err, , uint shortfall) = getHypotheticalAccountLiquidityInternal(borrower, CToken(cToken), 0, borrowAmount);
if (err != Error.NO_ERROR) {
return uint(err);
}
if (shortfall > 0) {
return uint(Error.INSUFFICIENT_LIQUIDITY);
}
// Keep the flywheel moving
Exp memory borrowIndex = Exp({mantissa: CToken(cToken).borrowIndex()});
updateCompBorrowIndex(cToken, borrowIndex);
distributeBorrowerComp(cToken, borrower, borrowIndex);
return uint(Error.NO_ERROR);
}
/**
* @notice Validates borrow and reverts on rejection. May emit logs.
* @param cToken Asset whose underlying is being borrowed
* @param borrower The address borrowing the underlying
* @param borrowAmount The amount of the underlying asset requested to borrow
*/
// function borrowVerify(address cToken, address borrower, uint borrowAmount) external {
// // // Shh - currently unused
// // cToken;
// // borrower;
// // borrowAmount;
// // // Shh - we don't ever want this hook to be marked pure
// // if (false) {
// // maxAssets = maxAssets;
// // }
// }
/**
* @notice Checks if the account should be allowed to repay a borrow in the given market
* @param cToken The market to verify the repay against
* @param payer The account which would repay the asset
* @param borrower The account which would borrowed the asset
* @param repayAmount The amount of the underlying asset the account would repay
* @return 0 if the repay is allowed, otherwise a semi-opaque error code (See ErrorReporter.sol)
*/
function repayBorrowAllowed(
address cToken,
address payer,
address borrower,
uint repayAmount) external returns (uint) {
// Shh - currently unused
payer;
borrower;
repayAmount;
if (!markets[cToken].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
// Keep the flywheel moving
Exp memory borrowIndex = Exp({mantissa: CToken(cToken).borrowIndex()});
updateCompBorrowIndex(cToken, borrowIndex);
distributeBorrowerComp(cToken, borrower, borrowIndex);
return uint(Error.NO_ERROR);
}
/**
* @notice Validates repayBorrow and reverts on rejection. May emit logs.
* @param cToken Asset being repaid
* @param payer The address repaying the borrow
* @param borrower The address of the borrower
* @param actualRepayAmount The amount of underlying being repaid
*/
// function repayBorrowVerify(
// address cToken,
// address payer,
// address borrower,
// uint actualRepayAmount,
// uint borrowerIndex) external {
// // Shh - currently unused
// cToken;
// payer;
// borrower;
// actualRepayAmount;
// borrowerIndex;
// // Shh - we don't ever want this hook to be marked pure
// if (false) {
// maxAssets = maxAssets;
// }
// }
/**
* @notice Checks if the liquidation should be allowed to occur
* @param cTokenBorrowed Asset which was borrowed by the borrower
* @param cTokenCollateral Asset which was used as collateral and will be seized
* @param liquidator The address repaying the borrow and seizing the collateral
* @param borrower The address of the borrower
* @param repayAmount The amount of underlying being repaid
*/
function liquidateBorrowAllowed(
address cTokenBorrowed,
address cTokenCollateral,
address liquidator,
address borrower,
uint repayAmount) external returns (uint) {
// Shh - currently unused
liquidator;
if (!markets[cTokenBorrowed].isListed || !markets[cTokenCollateral].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
if (liquidatorWhiteListOn) {
require(liquidatorWhiteList[liquidator], "liquidator not in white list");
}
uint borrowBalance = CToken(cTokenBorrowed).borrowBalanceStored(borrower);
/* allow accounts to be liquidated if the market is deprecated */
if (isDeprecated(CToken(cTokenBorrowed))) {
require(borrowBalance >= repayAmount, "Can not repay more than the total borrow");
} else {
/* The borrower must have shortfall in order to be liquidatable */
(Error err, , uint shortfall) = getAccountLiquidityInternal(borrower);
if (err != Error.NO_ERROR) {
return uint(err);
}
if (shortfall == 0) {
return uint(Error.INSUFFICIENT_SHORTFALL);
}
/* The liquidator may not repay more than what is allowed by the closeFactor */
uint maxClose = mul_ScalarTruncate(Exp({mantissa: closeFactorMantissa}), borrowBalance);
if (repayAmount > maxClose) {
return uint(Error.TOO_MUCH_REPAY);
}
}
return uint(Error.NO_ERROR);
}
/**
* @notice Validates liquidateBorrow and reverts on rejection. May emit logs.
* @param cTokenBorrowed Asset which was borrowed by the borrower
* @param cTokenCollateral Asset which was used as collateral and will be seized
* @param liquidator The address repaying the borrow and seizing the collateral
* @param borrower The address of the borrower
* @param actualRepayAmount The amount of underlying being repaid
*/
// function liquidateBorrowVerify(
// address cTokenBorrowed,
// address cTokenCollateral,
// address liquidator,
// address borrower,
// uint actualRepayAmount,
// uint seizeTokens) external {
// // // Shh - currently unused
// // cTokenBorrowed;
// // cTokenCollateral;
// // liquidator;
// // borrower;
// // actualRepayAmount;
// // seizeTokens;
// // // Shh - we don't ever want this hook to be marked pure
// // if (false) {
// // maxAssets = maxAssets;
// // }
// }
/**
* @notice Checks if the seizing of assets should be allowed to occur
* @param cTokenCollateral Asset which was used as collateral and will be seized
* @param cTokenBorrowed Asset which was borrowed by the borrower
* @param liquidator The address repaying the borrow and seizing the collateral
* @param borrower The address of the borrower
* @param seizeTokens The number of collateral tokens to seize
*/
function seizeAllowed(
address cTokenCollateral,
address cTokenBorrowed,
address liquidator,
address borrower,
uint seizeTokens) external returns (uint) {
// Pausing is a very serious situation - we revert to sound the alarms
require(!seizeGuardianPaused, "seize is paused");
// Shh - currently unused
seizeTokens;
if (!markets[cTokenCollateral].isListed || !markets[cTokenBorrowed].isListed) {
return uint(Error.MARKET_NOT_LISTED);
}
if (CToken(cTokenCollateral).comptroller() != CToken(cTokenBorrowed).comptroller()) {
return uint(Error.COMPTROLLER_MISMATCH);
}
// Keep the flywheel moving
updateCompSupplyIndex(cTokenCollateral);
distributeSupplierComp(cTokenCollateral, borrower);
distributeSupplierComp(cTokenCollateral, liquidator);
return uint(Error.NO_ERROR);
}
/**
* @notice Validates seize and reverts on rejection. May emit logs.
* @param cTokenCollateral Asset which was used as collateral and will be seized
* @param cTokenBorrowed Asset which was borrowed by the borrower
* @param liquidator The address repaying the borrow and seizing the collateral
* @param borrower The address of the borrower
* @param seizeTokens The number of collateral tokens to seize
*/
// function seizeVerify(
// address cTokenCollateral,
// address cTokenBorrowed,
// address liquidator,
// address borrower,
// uint seizeTokens) external {
// // // Shh - currently unused
// // cTokenCollateral;
// // cTokenBorrowed;
// // liquidator;
// // borrower;
// // seizeTokens;
// // // Shh - we don't ever want this hook to be marked pure
// // if (false) {
// // maxAssets = maxAssets;
// // }
// }
/**
* @notice Checks if the account should be allowed to transfer tokens in the given market
* @param cToken The market to verify the transfer against
* @param src The account which sources the tokens
* @param dst The account which receives the tokens
* @param transferTokens The number of cTokens to transfer
* @return 0 if the transfer is allowed, otherwise a semi-opaque error code (See ErrorReporter.sol)
*/
function transferAllowed(address cToken, address src, address dst, uint transferTokens) external returns (uint) {
// Pausing is a very serious situation - we revert to sound the alarms
require(!transferGuardianPaused, "transfer is paused");
// Currently the only consideration is whether or not
// the src is allowed to redeem this many tokens
uint allowed = redeemAllowedInternal(cToken, src, transferTokens);
if (allowed != uint(Error.NO_ERROR)) {
return allowed;
}
// Keep the flywheel moving
updateCompSupplyIndex(cToken);
distributeSupplierComp(cToken, src);
distributeSupplierComp(cToken, dst);
return uint(Error.NO_ERROR);
}
/**
* @notice Validates transfer and reverts on rejection. May emit logs.
* @param cToken Asset being transferred
* @param src The account which sources the tokens
* @param dst The account which receives the tokens
* @param transferTokens The number of cTokens to transfer
*/
// function transferVerify(address cToken, address src, address dst, uint transferTokens) external {
// // // Shh - currently unused
// // cToken;
// // src;
// // dst;
// // transferTokens;
// // // Shh - we don't ever want this hook to be marked pure
// // if (false) {
// // maxAssets = maxAssets;
// // }
// }
/*** Liquidity/Liquidation Calculations ***/
/**
* @dev Local vars for avoiding stack-depth limits in calculating account liquidity.
* Note that `cTokenBalance` is the number of cTokens the account owns in the market,
* whereas `borrowBalance` is the amount of underlying that the account has borrowed.
*/
struct AccountLiquidityLocalVars {
uint sumCollateral;
uint sumBorrowPlusEffects;
uint cTokenBalance;
uint borrowBalance;
uint exchangeRateMantissa;
uint oraclePriceMantissa;
Exp collateralFactor;
Exp exchangeRate;
Exp oraclePrice;
Exp tokensToDenom;
}
/**
* @notice Determine the current account liquidity wrt collateral requirements
* @return (possible error code (semi-opaque),
account liquidity in excess of collateral requirements,
* account shortfall below collateral requirements)
*/
function getAccountLiquidity(address account) public view returns (uint, uint, uint) {
(Error err, uint liquidity, uint shortfall) = getHypotheticalAccountLiquidityInternal(account, CToken(0), 0, 0);
return (uint(err), liquidity, shortfall);
}
/**
* @notice Determine the current account liquidity wrt collateral requirements
* @return (possible error code,
account liquidity in excess of collateral requirements,
* account shortfall below collateral requirements)
*/
function getAccountLiquidityInternal(address account) internal view returns (Error, uint, uint) {
return getHypotheticalAccountLiquidityInternal(account, CToken(0), 0, 0);
}
/**
* @notice Determine what the account liquidity would be if the given amounts were redeemed/borrowed
* @param cTokenModify The market to hypothetically redeem/borrow in
* @param account The account to determine liquidity for
* @param redeemTokens The number of tokens to hypothetically redeem
* @param borrowAmount The amount of underlying to hypothetically borrow
* @return (possible error code (semi-opaque),
hypothetical account liquidity in excess of collateral requirements,
* hypothetical account shortfall below collateral requirements)
*/
function getHypotheticalAccountLiquidity(
address account,
address cTokenModify,
uint redeemTokens,
uint borrowAmount) public view returns (uint, uint, uint) {
(Error err, uint liquidity, uint shortfall) = getHypotheticalAccountLiquidityInternal(account, CToken(cTokenModify), redeemTokens, borrowAmount);
return (uint(err), liquidity, shortfall);
}
/**
* @notice Determine what the account liquidity would be if the given amounts were redeemed/borrowed
* @param cTokenModify The market to hypothetically redeem/borrow in
* @param account The account to determine liquidity for
* @param redeemTokens The number of tokens to hypothetically redeem
* @param borrowAmount The amount of underlying to hypothetically borrow
* @dev Note that we calculate the exchangeRateStored for each collateral cToken using stored data,
* without calculating accumulated interest.
* @return (possible error code,
hypothetical account liquidity in excess of collateral requirements,
* hypothetical account shortfall below collateral requirements)
*/
function getHypotheticalAccountLiquidityInternal(
address account,
CToken cTokenModify,
uint redeemTokens,
uint borrowAmount) internal view returns (Error, uint, uint) {
AccountLiquidityLocalVars memory vars; // Holds all our calculation results
uint oErr;
// For each asset the account is in
CToken[] memory assets = accountAssets[account];
for (uint i = 0; i < assets.length; i++) {
CToken asset = assets[i];
// Read the balances and exchange rate from the cToken
(oErr, vars.cTokenBalance, vars.borrowBalance, vars.exchangeRateMantissa) = asset.getAccountSnapshot(account);
if (oErr != 0) { // semi-opaque error code, we assume NO_ERROR == 0 is invariant between upgrades
return (Error.SNAPSHOT_ERROR, 0, 0);
}
vars.collateralFactor = Exp({mantissa: markets[address(asset)].collateralFactorMantissa});
vars.exchangeRate = Exp({mantissa: vars.exchangeRateMantissa});
// Get the normalized price of the asset
vars.oraclePriceMantissa = oracle.getUnderlyingPrice(asset);
if (vars.oraclePriceMantissa == 0) {
return (Error.PRICE_ERROR, 0, 0);
}
vars.oraclePrice = Exp({mantissa: vars.oraclePriceMantissa});
// Pre-compute a conversion factor from tokens -> ether (normalized price value)
vars.tokensToDenom = mul_(mul_(vars.collateralFactor, vars.exchangeRate), vars.oraclePrice);
// sumCollateral += tokensToDenom * cTokenBalance
vars.sumCollateral = mul_ScalarTruncateAddUInt(vars.tokensToDenom, vars.cTokenBalance, vars.sumCollateral);
// sumBorrowPlusEffects += oraclePrice * borrowBalance
vars.sumBorrowPlusEffects = mul_ScalarTruncateAddUInt(vars.oraclePrice, vars.borrowBalance, vars.sumBorrowPlusEffects);
// Calculate effects of interacting with cTokenModify
if (asset == cTokenModify) {
// redeem effect
// sumBorrowPlusEffects += tokensToDenom * redeemTokens
vars.sumBorrowPlusEffects = mul_ScalarTruncateAddUInt(vars.tokensToDenom, redeemTokens, vars.sumBorrowPlusEffects);
// borrow effect
// sumBorrowPlusEffects += oraclePrice * borrowAmount
vars.sumBorrowPlusEffects = mul_ScalarTruncateAddUInt(vars.oraclePrice, borrowAmount, vars.sumBorrowPlusEffects);
}
}
// These are safe, as the underflow condition is checked first
if (vars.sumCollateral > vars.sumBorrowPlusEffects) {
return (Error.NO_ERROR, vars.sumCollateral - vars.sumBorrowPlusEffects, 0);
} else {
return (Error.NO_ERROR, 0, vars.sumBorrowPlusEffects - vars.sumCollateral);
}
}
/**
* @notice Calculate number of tokens of collateral asset to seize given an underlying amount
* @dev Used in liquidation (called in cToken.liquidateBorrowFresh)
* @param cTokenBorrowed The address of the borrowed cToken
* @param cTokenCollateral The address of the collateral cToken
* @param actualRepayAmount The amount of cTokenBorrowed underlying to convert into cTokenCollateral tokens
* @return (errorCode, number of cTokenCollateral tokens to be seized in a liquidation)
*/
function liquidateCalculateSeizeTokens(address cTokenBorrowed, address cTokenCollateral, uint actualRepayAmount) external view returns (uint, uint) {
/* Read oracle prices for borrowed and collateral markets */
uint priceBorrowedMantissa = oracle.getUnderlyingPrice(CToken(cTokenBorrowed));
uint priceCollateralMantissa = oracle.getUnderlyingPrice(CToken(cTokenCollateral));
if (priceBorrowedMantissa == 0 || priceCollateralMantissa == 0) {
return (uint(Error.PRICE_ERROR), 0);
}
/*
* Get the exchange rate and calculate the number of collateral tokens to seize:
* seizeAmount = actualRepayAmount * liquidationIncentive * priceBorrowed / priceCollateral
* seizeTokens = seizeAmount / exchangeRate
* = actualRepayAmount * (liquidationIncentive * priceBorrowed) / (priceCollateral * exchangeRate)
*/
uint exchangeRateMantissa = CToken(cTokenCollateral).exchangeRateStored(); // Note: reverts on error
uint seizeTokens;
Exp memory numerator;
Exp memory denominator;
Exp memory ratio;
numerator = mul_(Exp({mantissa: liquidationIncentiveMantissa}), Exp({mantissa: priceBorrowedMantissa}));
denominator = mul_(Exp({mantissa: priceCollateralMantissa}), Exp({mantissa: exchangeRateMantissa}));
ratio = div_(numerator, denominator);
seizeTokens = mul_ScalarTruncate(ratio, actualRepayAmount);
return (uint(Error.NO_ERROR), seizeTokens);
}
/*** Admin Functions ***/
/**
* @notice Sets a new price oracle for the comptroller
* @dev Admin function to set a new price oracle
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function _setPriceOracle(PriceOracle newOracle) public returns (uint) {
// Check caller is admin
if (msg.sender != admin) {
return fail(Error.UNAUTHORIZED, FailureInfo.SET_PRICE_ORACLE_OWNER_CHECK);
}
// Track the old oracle for the comptroller
PriceOracle oldOracle = oracle;
// Set comptroller's oracle to newOracle
oracle = newOracle;
// Emit NewPriceOracle(oldOracle, newOracle)
emit NewPriceOracle(oldOracle, newOracle);
return uint(Error.NO_ERROR);
}
/**
* @notice Sets the closeFactor used when liquidating borrows
* @dev Admin function to set closeFactor
* @param newCloseFactorMantissa New close factor, scaled by 1e18
* @return uint 0=success, otherwise a failure
*/
function _setCloseFactor(uint newCloseFactorMantissa) external returns (uint) {
// Check caller is admin
require(msg.sender == admin, "only admin can set close factor");
uint oldCloseFactorMantissa = closeFactorMantissa;
closeFactorMantissa = newCloseFactorMantissa;
emit NewCloseFactor(oldCloseFactorMantissa, closeFactorMantissa);
return uint(Error.NO_ERROR);
}
/**
* @notice Sets the collateralFactor for a market
* @dev Admin function to set per-market collateralFactor
* @param cToken The market to set the factor on
* @param newCollateralFactorMantissa The new collateral factor, scaled by 1e18
* @return uint 0=success, otherwise a failure. (See ErrorReporter for details)
*/
function _setCollateralFactor(CToken cToken, uint newCollateralFactorMantissa) external returns (uint) {
// Check caller is admin
if (msg.sender != admin) {
return fail(Error.UNAUTHORIZED, FailureInfo.SET_COLLATERAL_FACTOR_OWNER_CHECK);
}
// Verify market is listed
Market storage market = markets[address(cToken)];
if (!market.isListed) {
return fail(Error.MARKET_NOT_LISTED, FailureInfo.SET_COLLATERAL_FACTOR_NO_EXISTS);
}
Exp memory newCollateralFactorExp = Exp({mantissa: newCollateralFactorMantissa});
// Check collateral factor <= 0.9
Exp memory highLimit = Exp({mantissa: collateralFactorMaxMantissa});
if (lessThanExp(highLimit, newCollateralFactorExp)) {
return fail(Error.INVALID_COLLATERAL_FACTOR, FailureInfo.SET_COLLATERAL_FACTOR_VALIDATION);
}
// If collateral factor != 0, fail if price == 0
if (newCollateralFactorMantissa != 0 && oracle.getUnderlyingPrice(cToken) == 0) {
return fail(Error.PRICE_ERROR, FailureInfo.SET_COLLATERAL_FACTOR_WITHOUT_PRICE);
}
// Set market's collateral factor to new collateral factor, remember old value
uint oldCollateralFactorMantissa = market.collateralFactorMantissa;
market.collateralFactorMantissa = newCollateralFactorMantissa;
// Emit event with asset, old collateral factor, and new collateral factor
emit NewCollateralFactor(cToken, oldCollateralFactorMantissa, newCollateralFactorMantissa);
return uint(Error.NO_ERROR);
}
/**
* @notice Sets liquidationIncentive
* @dev Admin function to set liquidationIncentive
* @param newLiquidationIncentiveMantissa New liquidationIncentive scaled by 1e18
* @return uint 0=success, otherwise a failure. (See ErrorReporter for details)
*/
function _setLiquidationIncentive(uint newLiquidationIncentiveMantissa) external returns (uint) {
// Check caller is admin
if (msg.sender != admin) {
return fail(Error.UNAUTHORIZED, FailureInfo.SET_LIQUIDATION_INCENTIVE_OWNER_CHECK);
}
// Save current value for use in log
uint oldLiquidationIncentiveMantissa = liquidationIncentiveMantissa;
// Set liquidation incentive to new incentive
liquidationIncentiveMantissa = newLiquidationIncentiveMantissa;
// Emit event with old incentive, new incentive
emit NewLiquidationIncentive(oldLiquidationIncentiveMantissa, newLiquidationIncentiveMantissa);
return uint(Error.NO_ERROR);
}
/**
* @notice Add the market to the markets mapping and set it as listed
* @dev Admin function to set isListed and add support for the market
* @param cToken The address of the market (token) to list
* @return uint 0=success, otherwise a failure. (See enum Error for details)
*/
function _supportMarket(CToken cToken) external returns (uint) {
if (msg.sender != admin) {
return fail(Error.UNAUTHORIZED, FailureInfo.SUPPORT_MARKET_OWNER_CHECK);
}
if (markets[address(cToken)].isListed) {
return fail(Error.MARKET_ALREADY_LISTED, FailureInfo.SUPPORT_MARKET_EXISTS);
}
cToken.isCToken(); // Sanity check to make sure its really a CToken
// Note that isComped is not in active use anymore
markets[address(cToken)] = Market({isListed: true, isComped: false, collateralFactorMantissa: 0});
_addMarketInternal(address(cToken));
emit MarketListed(cToken);
return uint(Error.NO_ERROR);
}
function _addMarketInternal(address cToken) internal {
for (uint i = 0; i < allMarkets.length; i ++) {
require(allMarkets[i] != CToken(cToken), "market already added");
}
allMarkets.push(CToken(cToken));
}
function _setLiquidatorWhiteListOn(bool isOn) external {
require(msg.sender == admin, "Only admin can call this");
liquidatorWhiteListOn = isOn;
emit LiquidatorWhiteListOnUpdated(isOn);
}
function _addLiquidator(address liquidator) external {
require(msg.sender == admin, "Only admin can call this");
require(liquidator != address(0), "liquidator is zero address");
liquidatorWhiteList[liquidator] = true;
emit LiquidatorAdded(liquidator);
}
function _removeLiquidator(address liquidator) external {
require(msg.sender == admin, "Only admin can call this");
require(liquidator != address(0), "liquidator is zero address");
require(liquidatorWhiteList[liquidator] == true, "liquidator not in");
liquidatorWhiteList[liquidator] = false;
emit LiquidatorRemoved(liquidator);
}
/**
* @notice Set the given borrow caps for the given cToken markets. Borrowing that brings total borrows to or above borrow cap will revert.
* @dev Admin or borrowCapGuardian function to set the borrow caps. A borrow cap of 0 corresponds to unlimited borrowing.
* @param cTokens The addresses of the markets (tokens) to change the borrow caps for
* @param newBorrowCaps The new borrow cap values in underlying to be set. A value of 0 corresponds to unlimited borrowing.
*/
function _setMarketBorrowCaps(CToken[] calldata cTokens, uint[] calldata newBorrowCaps) external {
require(msg.sender == admin || msg.sender == borrowCapGuardian, "only admin or borrow cap guardian can set borrow caps");
uint numMarkets = cTokens.length;
uint numBorrowCaps = newBorrowCaps.length;
require(numMarkets != 0 && numMarkets == numBorrowCaps, "invalid input");
for(uint i = 0; i < numMarkets; i++) {
borrowCaps[address(cTokens[i])] = newBorrowCaps[i];
emit NewBorrowCap(cTokens[i], newBorrowCaps[i]);
}