From 793e338dd3ebd84c2de9fbade3c63bc0c1ac39dc Mon Sep 17 00:00:00 2001
From: Amir Bandeali <abandeali1@gmail.com>
Date: Sun, 25 Aug 2019 17:06:52 -0700
Subject: [PATCH] Revert to old ReentrancyGuard implementation

---
 .../utils/contracts/src/ReentrancyGuard.sol   | 26 +++++++++++--------
 .../contracts/test/TestReentrancyGuard.sol    | 11 ++------
 2 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/contracts/utils/contracts/src/ReentrancyGuard.sol b/contracts/utils/contracts/src/ReentrancyGuard.sol
index c0b7e4750a..550e94ac90 100644
--- a/contracts/utils/contracts/src/ReentrancyGuard.sol
+++ b/contracts/utils/contracts/src/ReentrancyGuard.sol
@@ -24,22 +24,26 @@ import "./LibRichErrors.sol";
 
 contract ReentrancyGuard {
 
-    // Mutex counter.
-    // Starts at 1 and increases whenever a nonReentrant function is called.
-    uint256 private reentrancyGuardCounter = 1;
+    // Locked state of mutex.
+    bool private locked = false;
 
-    /// @dev Functions with this modifer cannot be reentered.
+    /// @dev Functions with this modifer cannot be reentered. The mutex will be locked
+    ///      before function execution and unlocked after.
     modifier nonReentrant() {
-        // Increment and remember the current counter value.
-        uint256 localCounter = ++reentrancyGuardCounter;
-        // Call the function.
-        _;
-        // If the counter value is different from what we remember, the function
-        // was called more than once and an illegal reentrancy occured.
-        if (localCounter != reentrancyGuardCounter) {
+        // Ensure mutex is unlocked.
+        if (locked) {
             LibRichErrors.rrevert(
                 LibReentrancyGuardRichErrors.IllegalReentrancyError()
             );
         }
+
+        // Lock mutex before function call
+        locked = true;
+
+        // Perform function call
+        _;
+
+        // Unlock mutex after function call
+        locked = false;
     }
 }
diff --git a/contracts/utils/contracts/test/TestReentrancyGuard.sol b/contracts/utils/contracts/test/TestReentrancyGuard.sol
index 7a878fd072..3bf6d3d274 100644
--- a/contracts/utils/contracts/test/TestReentrancyGuard.sol
+++ b/contracts/utils/contracts/test/TestReentrancyGuard.sol
@@ -24,8 +24,6 @@ import "../src/ReentrancyGuard.sol";
 contract TestReentrancyGuard is
     ReentrancyGuard
 {
-    uint256 internal counter = 2;
-
     /// @dev Exposes the nonReentrant modifier publicly.
     /// @param shouldBeAttacked True if the contract should be attacked.
     /// @return True if successful.
@@ -47,19 +45,14 @@ contract TestReentrancyGuard is
         external
         returns (bool)
     {
-        if (counter > 0) {
-            counter--;
-            this.guarded(true);
-        } else {
-            counter = 2;
-            return true;
-        }
+        return this.guarded(true);
     }
 
     /// @dev This is a function that will not reenter the current contract.
     /// @return True if successful.
     function nonExploitive()
         external
+        pure
         returns (bool)
     {
         return true;