export fault injection suspend/resume from usersim.dll

inc/usersim/common.h

@@ -8,3 +8,26 @@
 #else
 #define USERSIM_API __declspec(dllimport)
 #endif
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/**
+ * @brief Suspend fault injection within usersim.dll.
+ *
+ * Calls may be nested and must be balanced by calls to usersim_fault_injection_resume().
+ */
+USERSIM_API void
+usersim_fault_injection_suspend();
+
+/**
+ * @brief Resume fault injection within usersim.dll after a matching suspension.
+ */
+USERSIM_API void
+usersim_fault_injection_resume();
+
+#ifdef __cplusplus
+}
+#endif

src/Source.def

@@ -51,3 +51,6 @@ EXPORTS
     NmrRegisterProvider
     NmrWaitForClientDeregisterComplete
     NmrWaitForProviderDeregisterComplete
+
+    usersim_fault_injection_resume
+    usersim_fault_injection_suspend

src/platform_user.cpp

@@ -4,6 +4,7 @@
 #include "cxplat.h"
 #include "cxplat_fault_injection.h"
 #include "tracelog.h"
+#include "usersim/common.h"
 #include "usersim/ex.h"
 #include "usersim/ke.h"
 #include "usersim/mm.h"
@@ -45,6 +46,18 @@ static bool _cxplat_initialized = false;
 // Used to compute the current CPU index.
 static std::vector<uint32_t> _usersim_platform_group_to_index_map;
 
+void
+usersim_fault_injection_suspend()
+{
+    cxplat_fault_injection_suspend();
+}
+
+void
+usersim_fault_injection_resume()
+{
+    cxplat_fault_injection_resume();
+}
+
 _Must_inspect_result_ usersim_result_t
 usersim_platform_initiate()
 {

tests/CMakeLists.txt

@@ -14,6 +14,7 @@ FetchContent_MakeAvailable(Catch2)
 add_executable(usersim_tests
   etw_test.cpp
   ex_test.cpp
+  fault_injection_test.cpp
   ke_test.cpp
   mm_test.cpp
   nmr_test.cpp

tests/fault_injection_test.cpp

@@ -0,0 +1,44 @@
+// Copyright (c) Microsoft Corporation
+// SPDX-License-Identifier: MIT
+
+#if !defined(CMAKE_NUGET)
+#include <catch2/catch_all.hpp>
+#else
+#include <catch2/catch.hpp>
+#endif
+
+#include "usersim/common.h"
+#include "usersim/ex.h"
+
+#include <cstdlib>
+
+static bool
+_is_fault_injection_enabled()
+{
+    char value[32] = {};
+    size_t required_size = 0;
+    getenv_s(&required_size, value, sizeof(value), "CXPLAT_FAULT_INJECTION_SIMULATION");
+    return required_size > 0 && std::strtoull(value, nullptr, 10) > 0;
+}
+
+TEST_CASE("usersim fault injection suspension", "[fault_injection]")
+{
+    auto call_fault_injected_usersim_api = []() {
+        UUID uuid = {};
+        return ExUuidCreate(&uuid);
+    };
+
+    usersim_fault_injection_suspend();
+    usersim_fault_injection_suspend();
+    NTSTATUS nested_suspension_status = call_fault_injected_usersim_api();
+
+    usersim_fault_injection_resume();
+    NTSTATUS single_suspension_status = call_fault_injected_usersim_api();
+
+    usersim_fault_injection_resume();
+    NTSTATUS resumed_status = call_fault_injected_usersim_api();
+
+    REQUIRE(nested_suspension_status == STATUS_SUCCESS);
+    REQUIRE(single_suspension_status == STATUS_SUCCESS);
+    REQUIRE(resumed_status == (_is_fault_injection_enabled() ? STATUS_NOT_SUPPORTED : STATUS_SUCCESS));
+}

tests/tests.vcxproj

@@ -74,6 +74,7 @@
   <ItemGroup>
     <ClCompile Include="etw_test.cpp" />
     <ClCompile Include="ex_test.cpp" />
+    <ClCompile Include="fault_injection_test.cpp" />
     <ClCompile Include="io_test.cpp" />
     <ClCompile Include="ke_test.cpp" />
     <ClCompile Include="mm_test.cpp" />