[ETW] Fix infinite loop in ETWProvider::close (#3827)

Author: ThomsonTan

CHANGELOG.md

@@ -15,6 +15,9 @@ Increment the:
 
 ## [Unreleased]
 
+* [ETW] Fix infinite loop in ETWProvider::close
+  [#3827](https://github.com/open-telemetry/opentelemetry-cpp/pull/3827)
+
 * [CONFIGURATION] File configuration - remove zipkin
   [#3804](https://github.com/open-telemetry/opentelemetry-cpp/pull/3804)
 

exporters/etw/include/opentelemetry/exporters/etw/etw_provider.h

@@ -210,6 +210,11 @@ class ETWProvider
         auto &data           = it->second;
         unsigned long result = STATUS_OK;
 
+        if (data.refCount == 0)
+        {
+          return STATUS_ERROR;
+        }
+
         data.refCount--;
         if (data.refCount == 0)
         {
@@ -232,6 +237,7 @@ class ETWProvider
         }
         return result;
       }
+      ++it;
     }
     return STATUS_ERROR;
   }

exporters/etw/test/etw_provider_test.cc

@@ -61,4 +61,36 @@ TEST(ETWProvider, CheckCloseSuccess)
   ASSERT_FALSE(etw.is_registered(providerName));
 }
 
+TEST(ETWProvider, CheckCloseInfiniteLoop)
+{
+  std::string providerName1 = "Provider1";
+  std::string providerName2 = "Provider2";
+
+  static ETWProvider etw;
+  auto handle1 = etw.open(providerName1.c_str());
+  auto handle2 = etw.open(providerName2.c_str());
+
+  // This should not hang
+  auto result2 = etw.close(handle2);
+  ASSERT_EQ(result2, etw.STATUS_OK);
+  ASSERT_FALSE(etw.is_registered(providerName2));
+
+  auto result1 = etw.close(handle1);
+  ASSERT_EQ(result1, etw.STATUS_OK);
+  ASSERT_FALSE(etw.is_registered(providerName1));
+}
+
+TEST(ETWProvider, CheckCloseRefCountUnderflow)
+{
+  std::string providerName = "OpenTelemetry-ETW-Provider-Underflow";
+  static ETWProvider etw;
+  auto handle = etw.open(providerName.c_str());
+  auto result = etw.close(handle);
+  ASSERT_EQ(result, etw.STATUS_OK);
+
+  // Subsequent close should fail
+  result = etw.close(handle);
+  ASSERT_EQ(result, etw.STATUS_ERROR);
+}
+
 #endif