[java-interop, Java.Interop] Securely load native libs

Fixes: #676

Context: https://liquid.microsoft.com/Web/Object/Read/ms.security/Requirements/Microsoft.Security.SystemsADM.10039#guide

The current security guidance is that the
[`System.Runtime.InteropServices.DefaultDllImportSearchPathsAttribute`][0]
attribute should be placed either on the assembly or on `[DllImport]`
methods to control and constrain where [`LoadLibraryEx()`][1] will look
for native libraries, in particular to *prevent* looking for native
libraries within e.g. the current working directory or `%PATH%` or any
other "attacker-controlled" location.

Update `Java.Interop.dll` and `Java.Runtime.Environment.dll` so that
the [`DllImportSearchPath`][2] values `AssemblyDirectory` and
`SafeDirectories` are used:

  * `AssemblyDirectory`: "include the directory that contains the
    assembly itself, and search that directory first."

  * `SafeDirectories`: "Include the application directory, the
    `%WinDir%\System32` directory, and user directories in the DLL
    search path.

Additionally, update `src/java-interop` so that instead of requiring
the use of [**dlopen**(3)] on Windows, the following new exports are
added to support loading native libraries and resolving symbols from
those native libraries:

	void*   java_interop_load_library (const char *path, unsigned int flags, char **error);
	void*   java_interop_get_symbol_address (void* library, const char *symbol, char **error);
	int     java_interop_close_library (void* library, char **error);

On Windows, `java_interop_load_library()` will use
[`LoadLibraryEx()`][4] to load libraries from a constrained set of
directories:

  * `LOAD_LIBRARY_SEARCH_APPLICATION_DIR`: "the application's
    installation directory is searched for the DLL and its dependencies"

  * `LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR`: "the directory that contains
    the DLL is temporarily added to the beginning of the list of
    directories that are searched for the DLL's dependencies."

  * `LOAD_LIBRARY_SEARCH_USER_DIRS`: "directories added using the
    `AddDllDirectory()` or the `SetDllDirectory()` function are searched
    for the DLL and its dependencies"

In order to simplify the introduction of
`java_interop_load_library()`, start *requiring* the presence of the
symbols `mono_thread_get_managed_id` and `mono_thread_get_name_utf8`.
These symbols have been present within Mono for ages at this point,
and requiring means we don't need to support `dlopen(NULL)` semantics.

Update the `@(ClInclude)` item group and `BuildMac` and related targets
so that we properly rebuild things when e.g. `java-interop-dlfcn.h`
changes, as would "normally" be expected.

Finally, the continued use of `MONO_API` and other macros causes
"weird" compiler issues when integrating with xamarin-android.
Replace `MONO_API`/etc. use with `JAVA_INTEROP_API`/etc. instead.

[0]: https://docs.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.defaultdllimportsearchpathsattribute?view=netcore-3.1
[1]: https://docs.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa?redirectedfrom=MSDN
[2]: https://docs.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.dllimportsearchpath?view=netcore-3.1
[3]: https://linux.die.net/man/3/dlopen
[4]: https://docs.microsoft.com/en-us/windows/win32/api/libloaderapi/nf-libloaderapi-loadlibraryexa

src/Java.Interop/Java.Interop/JniRuntime.cs

@@ -9,6 +9,8 @@
 using System.Runtime.InteropServices;
 using System.Threading;
 
+[assembly: DefaultDllImportSearchPathsAttribute (DllImportSearchPath.SafeDirectories | DllImportSearchPath.AssemblyDirectory)]
+
 namespace Java.Interop
 {
 	delegate int DestroyJavaVMDelegate (IntPtr javavm);

src/Java.Runtime.Environment/Java.Interop/JreRuntime.cs

@@ -7,6 +7,8 @@
 using System.Runtime.InteropServices;
 using System.Threading;
 
+[assembly: DefaultDllImportSearchPathsAttribute (DllImportSearchPath.SafeDirectories | DllImportSearchPath.AssemblyDirectory)]
+
 namespace Java.Interop {
 
 	struct JavaVMInitArgs {

src/java-interop/java-interop-gc-bridge-mono.cc

@@ -24,8 +24,6 @@
 	#include "logger.h"
 #endif  /* !defined (ANDROID) */
 
-#include <dlfcn.h>
-
 #if defined (ANDROID) || defined (XAMARIN_ANDROID_DYLIB_MONO)
 using namespace xamarin::android;
 #endif
@@ -76,23 +74,6 @@ struct JavaInteropGCBridge {
 	int                                 gref_cleanup,   lref_cleanup;
 };
 
-typedef char* (*MonoThreadGetNameUtf8)(MonoThread*);
-typedef int32_t (*MonoThreadGetManagedId)(MonoThread*);
-
-static MonoThreadGetManagedId    _mono_thread_get_managed_id;
-static MonoThreadGetNameUtf8     _mono_thread_get_name_utf8;
-
-static void
-lookup_optional_mono_thread_functions (void)
-{
-	void *h = dlopen (NULL, RTLD_LAZY);
-	if (!h)
-		return;
-
-	_mono_thread_get_managed_id     = reinterpret_cast<MonoThreadGetManagedId>(dlsym (h, "mono_thread_get_managed_id"));
-	_mono_thread_get_name_utf8      = reinterpret_cast<MonoThreadGetNameUtf8>(dlsym (h, "mono_thread_get_name_utf8"));
-}
-
 static jobject
 lref_to_gref (JNIEnv *env, jobject lref)
 {
@@ -275,8 +256,6 @@ java_interop_gc_bridge_new (JavaVM *jvm)
 	}
 #endif  /* defined (XAMARIN_ANDROID_DYLIB_MONO) */
 
-	lookup_optional_mono_thread_functions ();
-
 	JavaInteropGCBridge bridge = {0};
 
 	bridge.jvm  = jvm;
@@ -1237,26 +1216,15 @@ gc_is_bridge_object (MonoObject *object)
 static char *
 get_thread_name (void)
 {
-	if (_mono_thread_get_name_utf8) {
-		MonoThread *thread = mono_thread_current ();
-		return _mono_thread_get_name_utf8 (thread);
-	}
-	return strdup ("finalizer");
+	MonoThread *thread = mono_thread_current ();
+	return mono_thread_get_name_utf8 (thread);
 }
 
 static int64_t
 get_thread_id (void)
 {
-	if (_mono_thread_get_managed_id) {
-		MonoThread *thread = mono_thread_current ();
-		return _mono_thread_get_managed_id (thread);
-	}
-#if __linux__
-	int64_t tid = (int64_t)((pid_t)syscall(SYS_gettid));
-#else
-	int64_t tid = (int64_t) pthread_self ();
-#endif
-	return tid;
+	MonoThread *thread = mono_thread_current ();
+	return mono_thread_get_managed_id (thread);
 }
 
 static void

src/java-interop/java-interop-gc-bridge.h

@@ -19,41 +19,41 @@ struct JavaInterop_System_RuntimeTypeHandle {
 	void   *value;
 };
 
-MONO_API    JavaInteropGCBridge    *java_interop_gc_bridge_get_current                  (void);
-MONO_API    int                     java_interop_gc_bridge_set_current_once             (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    JavaInteropGCBridge    *java_interop_gc_bridge_get_current                  (void);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_set_current_once             (JavaInteropGCBridge *bridge);
 
-MONO_API    JavaInteropGCBridge    *java_interop_gc_bridge_new                          (JavaVM *jvm);
-MONO_API    int                     java_interop_gc_bridge_free                         (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    JavaInteropGCBridge    *java_interop_gc_bridge_new                          (JavaVM *jvm);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_free                         (JavaInteropGCBridge *bridge);
 
-MONO_API    int                     java_interop_gc_bridge_register_hooks               (JavaInteropGCBridge *bridge, int weak_ref_kind);
-MONO_API    int                     java_interop_gc_bridge_wait_for_bridge_processing   (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_register_hooks               (JavaInteropGCBridge *bridge, int weak_ref_kind);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_wait_for_bridge_processing   (JavaInteropGCBridge *bridge);
 
-MONO_API    int                     java_interop_gc_bridge_add_current_app_domain       (JavaInteropGCBridge *bridge);
-MONO_API    int                     java_interop_gc_bridge_remove_current_app_domain    (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_add_current_app_domain       (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_remove_current_app_domain    (JavaInteropGCBridge *bridge);
 
-MONO_API    int                     java_interop_gc_bridge_set_bridge_processing_field  (JavaInteropGCBridge *bridge,   struct JavaInterop_System_RuntimeTypeHandle type_handle,    char *field_name);
-MONO_API    int                     java_interop_gc_bridge_register_bridgeable_type     (JavaInteropGCBridge *bridge,   struct JavaInterop_System_RuntimeTypeHandle type_handle);
-MONO_API    int                     java_interop_gc_bridge_enable                       (JavaInteropGCBridge *bridge,   int enable);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_set_bridge_processing_field  (JavaInteropGCBridge *bridge,   struct JavaInterop_System_RuntimeTypeHandle type_handle,    char *field_name);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_register_bridgeable_type     (JavaInteropGCBridge *bridge,   struct JavaInterop_System_RuntimeTypeHandle type_handle);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_enable                       (JavaInteropGCBridge *bridge,   int enable);
 
-MONO_API    int                     java_interop_gc_bridge_get_gref_count           (JavaInteropGCBridge *bridge);
-MONO_API    int                     java_interop_gc_bridge_get_weak_gref_count      (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_get_gref_count           (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_get_weak_gref_count      (JavaInteropGCBridge *bridge);
 
-MONO_API    int                     java_interop_gc_bridge_lref_set_log_file        (JavaInteropGCBridge *bridge,   const char *gref_log_file);
-MONO_API    FILE*                   java_interop_gc_bridge_lref_get_log_file        (JavaInteropGCBridge *bridge);
-MONO_API    int                     java_interop_gc_bridge_lref_set_log_level       (JavaInteropGCBridge *bridge,   int level);
-MONO_API    void                    java_interop_gc_bridge_lref_log_message         (JavaInteropGCBridge *bridge,   int level, const char *message);
-MONO_API    void                    java_interop_gc_bridge_lref_log_new             (JavaInteropGCBridge *bridge,   int lref_count,     jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,   int64_t thread_id,  const char *from);
-MONO_API    void                    java_interop_gc_bridge_lref_log_delete          (JavaInteropGCBridge *bridge,   int lref_count,     jobject handle,     char type,                                          const char *thread_name,   int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_lref_set_log_file        (JavaInteropGCBridge *bridge,   const char *gref_log_file);
+JAVA_INTEROP_API    FILE*                   java_interop_gc_bridge_lref_get_log_file        (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_lref_set_log_level       (JavaInteropGCBridge *bridge,   int level);
+JAVA_INTEROP_API    void                    java_interop_gc_bridge_lref_log_message         (JavaInteropGCBridge *bridge,   int level, const char *message);
+JAVA_INTEROP_API    void                    java_interop_gc_bridge_lref_log_new             (JavaInteropGCBridge *bridge,   int lref_count,     jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,   int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    void                    java_interop_gc_bridge_lref_log_delete          (JavaInteropGCBridge *bridge,   int lref_count,     jobject handle,     char type,                                          const char *thread_name,   int64_t thread_id,  const char *from);
 
-MONO_API    int                     java_interop_gc_bridge_gref_set_log_file        (JavaInteropGCBridge *bridge,   const char *gref_log_file);
-MONO_API    FILE*                   java_interop_gc_bridge_gref_get_log_file        (JavaInteropGCBridge *bridge);
-MONO_API    int                     java_interop_gc_bridge_gref_set_log_level       (JavaInteropGCBridge *bridge,   int level);
-MONO_API    void                    java_interop_gc_bridge_gref_log_message         (JavaInteropGCBridge *bridge,   int level, const char *message);
-MONO_API    int                     java_interop_gc_bridge_gref_log_new             (JavaInteropGCBridge *bridge,   jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,    int64_t thread_id,  const char *from);
-MONO_API    int                     java_interop_gc_bridge_gref_log_delete          (JavaInteropGCBridge *bridge,   jobject handle,     char type,                                          const char *thread_name,    int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_gref_set_log_file        (JavaInteropGCBridge *bridge,   const char *gref_log_file);
+JAVA_INTEROP_API    FILE*                   java_interop_gc_bridge_gref_get_log_file        (JavaInteropGCBridge *bridge);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_gref_set_log_level       (JavaInteropGCBridge *bridge,   int level);
+JAVA_INTEROP_API    void                    java_interop_gc_bridge_gref_log_message         (JavaInteropGCBridge *bridge,   int level, const char *message);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_gref_log_new             (JavaInteropGCBridge *bridge,   jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,    int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_gref_log_delete          (JavaInteropGCBridge *bridge,   jobject handle,     char type,                                          const char *thread_name,    int64_t thread_id,  const char *from);
 
-MONO_API    int                     java_interop_gc_bridge_weak_gref_log_new        (JavaInteropGCBridge *bridge,   jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,    int64_t thread_id,  const char *from);
-MONO_API    int                     java_interop_gc_bridge_weak_gref_log_delete     (JavaInteropGCBridge *bridge,   jobject handle,     char type,                                          const char *thread_name,    int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_weak_gref_log_new        (JavaInteropGCBridge *bridge,   jobject curHandle,  char curType,   jobject newHandle,  char newType,   const char *thread_name,    int64_t thread_id,  const char *from);
+JAVA_INTEROP_API    int                     java_interop_gc_bridge_weak_gref_log_delete     (JavaInteropGCBridge *bridge,   jobject handle,     char type,                                          const char *thread_name,    int64_t thread_id,  const char *from);
 
 JAVA_INTEROP_END_DECLS
 

src/java-interop/java-interop-jvm.cc

@@ -1,7 +1,7 @@
 #include <stdlib.h>
-#include <dlfcn.h>
 
 #include "java-interop-jvm.h"
+#include "java-interop-dlfcn.h"
 #include "java-interop-logger.h"
 #include "java-interop-util.h"
 
@@ -33,11 +33,13 @@ java_interop_jvm_load_with_error_message (const char *path, char **error_message
 		return JAVA_INTEROP_JVM_FAILED_OOM;
 	}
 
-	jvm->dl_handle = dlopen (path, RTLD_LAZY);
+	char *error    = nullptr;
+	jvm->dl_handle = java_interop_load_library (path, 0, &error);
 	if (!jvm->dl_handle) {
 		if (error_message) {
-			*error_message = java_interop_strdup (dlerror ());
+			*error_message = java_interop_strdup (error);
 		}
+		free (error);
 		free (jvm);
 		jvm = NULL;
 		return JAVA_INTEROP_JVM_FAILED_NOT_LOADED;
@@ -46,10 +48,13 @@ java_interop_jvm_load_with_error_message (const char *path, char **error_message
 	int symbols_missing = 0;
 
 #define LOAD_SYMBOL_CAST(symbol, Type) do { \
-		jvm->symbol = reinterpret_cast<Type>(dlsym (jvm->dl_handle, #symbol)); \
+		error = nullptr; \
+		jvm->symbol = reinterpret_cast<Type>(java_interop_get_symbol_address (jvm->dl_handle, #symbol, &error)); \
 		if (!jvm->symbol) { \
-			log_error (LOG_DEFAULT, "Failed to load JVM symbol: %s", #symbol); \
+			log_error (LOG_DEFAULT, "Failed to load JVM symbol: %s: %s", #symbol, error); \
 			symbols_missing = 1; \
+			free (error); \
+			error = nullptr; \
 		} \
 	} while (0)
 #define LOAD_SYMBOL(symbol) LOAD_SYMBOL_CAST(symbol, java_interop_ ## symbol ## _fptr)
@@ -61,7 +66,7 @@ java_interop_jvm_load_with_error_message (const char *path, char **error_message
 #undef LOAD_SYMBOL
 
 	if (symbols_missing) {
-		dlclose (jvm->dl_handle);
+		java_interop_close_library (jvm->dl_handle, nullptr);
 		free (jvm);
 		jvm = NULL;
 		return JAVA_INTEROP_JVM_FAILED_SYMBOL_MISSING;

src/java-interop/java-interop-jvm.h

@@ -13,10 +13,10 @@ JAVA_INTEROP_BEGIN_DECLS
 #define JAVA_INTEROP_JVM_FAILED_OOM             (JAVA_INTEROP_JVM_FAILED-3)
 #define JAVA_INTEROP_JVM_FAILED_SYMBOL_MISSING  (JAVA_INTEROP_JVM_FAILED-4)
 
-MONO_API    int java_interop_jvm_load (const char *path);
-MONO_API    int java_interop_jvm_load_with_error_message (const char *path, char **error);
-MONO_API    int java_interop_jvm_create (JavaVM **p_vm, void **p_env, void *vm_args);
-MONO_API    int java_interop_jvm_list (JavaVM **vmBuf, int bufLen, int *nVMs);
+JAVA_INTEROP_API    int java_interop_jvm_load (const char *path);
+JAVA_INTEROP_API    int java_interop_jvm_load_with_error_message (const char *path, char **error);
+JAVA_INTEROP_API    int java_interop_jvm_create (JavaVM **p_vm, void **p_env, void *vm_args);
+JAVA_INTEROP_API    int java_interop_jvm_list (JavaVM **vmBuf, int bufLen, int *nVMs);
 
 JAVA_INTEROP_END_DECLS
 

src/java-interop/java-interop-mono.h

@@ -3,43 +3,13 @@
 
 #include "java-interop.h"
 
-#if defined (XAMARIN_ANDROID_DYLIB_MONO)
-
-	#include "dylib-mono.h"
-	#include "monodroid-glue.h"
-
-	#define mono_class_from_mono_type               (monodroid_get_dylib ()->class_from_mono_type)
-	#define mono_class_from_name                    (monodroid_get_dylib ()->class_from_name)
-	#define mono_class_get_field_from_name          (monodroid_get_dylib ()->class_get_field_from_name)
-	#define mono_class_get_name                     (monodroid_get_dylib ()->class_get_name)
-	#define mono_class_get_namespace                (monodroid_get_dylib ()->class_get_namespace)
-	#define mono_class_is_subclass_of               (monodroid_get_dylib ()->class_is_subclass_of)
-	#define mono_class_vtable                       (monodroid_get_dylib ()->class_vtable)
-	#define mono_domain_get                         (monodroid_get_dylib ()->domain_get)
-	#define mono_field_get_value                    (monodroid_get_dylib ()->field_get_value)
-	#define mono_field_set_value                    (monodroid_get_dylib ()->field_set_value)
-	#define mono_field_static_set_value             (monodroid_get_dylib ()->field_static_set_value)
-	#define mono_object_get_class                   (monodroid_get_dylib ()->object_get_class)
-	#define mono_thread_attach                      (monodroid_get_dylib ()->thread_attach)
-	#define mono_thread_current                     (monodroid_get_dylib ()->thread_current)
-	#define mono_gc_register_bridge_callbacks       (monodroid_get_dylib ()->gc_register_bridge_callbacks)
-	#define mono_gc_wait_for_bridge_processing      (monodroid_get_dylib ()->gc_wait_for_bridge_processing)
-
-#else   /* !defined (XAMARIN_ANDROID_DYLIB_MONO) */
-
-	#undef MONO_API_EXPORT
-	#undef MONO_API_IMPORT
-	#undef MONO_API
-
-	#include <mono/metadata/assembly.h>
-	#include <mono/metadata/class.h>
-	#include <mono/metadata/object.h>
-	#include <mono/metadata/sgen-bridge.h>
-	#include <mono/metadata/threads.h>
-	#include <mono/utils/mono-counters.h>
-	#include <mono/utils/mono-dl-fallback.h>
-
-#endif  /* !defined (XAMARIN_ANDROID_DYLIB_MONO) */
+#include <mono/metadata/assembly.h>
+#include <mono/metadata/class.h>
+#include <mono/metadata/object.h>
+#include <mono/metadata/sgen-bridge.h>
+#include <mono/metadata/threads.h>
+#include <mono/utils/mono-counters.h>
+#include <mono/utils/mono-dl-fallback.h>
 
 JAVA_INTEROP_BEGIN_DECLS
 

src/java-interop/java-interop-util.h

@@ -1,6 +1,8 @@
 #ifndef __JAVA_INTEROP_UTIL_H__
 #define __JAVA_INTEROP_UTIL_H__
 
+#include <cstdlib>
+
 #ifdef WINDOWS
 /* Those two conversion functions are only properly implemented on Windows
  * because that's the only place where they should be useful.
@@ -44,7 +46,7 @@ _assert_valid_pointer (void *p, size_t size)
 		}
 
 		log_fatal (LOG_DEFAULT, "Out of memory!");
-		exit (FATAL_EXIT_OUT_OF_MEMORY);
+		std::exit (FATAL_EXIT_OUT_OF_MEMORY);
 	}
 
 	return p;

src/java-interop/java-interop.csproj

@@ -4,7 +4,7 @@
     <OutputPath>$(ToolOutputFullPath)</OutputPath>
     <JNIEnvGenPath>$(BuildToolOutputFullPath)</JNIEnvGenPath>
     <OutputName>java-interop</OutputName>
-    <DefineSymbols>JI_DLL_EXPORT MONODEVELOP MONO_DLL_EXPORT</DefineSymbols>
+    <DefineSymbols>JI_DLL_EXPORT MONODEVELOP JAVA_INTEROP_DLL_EXPORT</DefineSymbols>
     <SourceDirectory>.</SourceDirectory>
   </PropertyGroup>
 
@@ -18,8 +18,12 @@
 
   <ItemGroup>
     <ClInclude Include="java-interop.h" />
+    <ClInclude Include="java-interop-dlfcn.h" />
     <ClInclude Include="java-interop-gc-bridge.h" />
+    <ClInclude Include="java-interop-jvm.h" />
+    <ClInclude Include="java-interop-logger.h" />
     <ClInclude Include="java-interop-mono.h" />
+    <ClInclude Include="java-interop-util.h" />
   </ItemGroup>
 
   <PropertyGroup>
@@ -37,6 +41,7 @@
   <ItemGroup>
     <ClCompile Include="jni.c" />
     <ClCompile Include="java-interop.cc" />
+    <ClCompile Include="java-interop-dlfcn.cc" />
     <ClCompile Include="java-interop-jvm.cc" />
     <ClCompile Include="java-interop-logger.cc" />
     <ClCompile Include="java-interop-mono.cc" />

src/java-interop/java-interop.h

@@ -5,26 +5,26 @@
 
 #if defined(_MSC_VER)
 
-	#define MONO_API_EXPORT __declspec(dllexport)
-	#define MONO_API_IMPORT __declspec(dllimport)
+	#define JAVA_INTEROP_API_EXPORT __declspec(dllexport)
+	#define JAVA_INTEROP_API_IMPORT __declspec(dllimport)
 
 #else   /* defined(_MSC_VER */
 
 	#ifdef __GNUC__
-		#define MONO_API_EXPORT __attribute__ ((visibility ("default")))
+		#define JAVA_INTEROP_API_EXPORT __attribute__ ((visibility ("default")))
 	#else
-		#define MONO_API_EXPORT
+		#define JAVA_INTEROP_API_EXPORT
 	#endif
-	#define MONO_API_IMPORT
+	#define JAVA_INTEROP_API_IMPORT
 
 #endif  /* !defined(_MSC_VER) */
 
-#if defined(MONO_DLL_EXPORT)
-	#define MONO_API MONO_API_EXPORT
-#elif defined(MONO_DLL_IMPORT)
-	#define MONO_API MONO_API_IMPORT
-#else   /* !defined(MONO_DLL_IMPORT) && !defined(MONO_API_IMPORT) */
-	#define MONO_API
+#if defined(MONO_DLL_EXPORT) || defined(JAVA_INTEROP_DLL_EXPORT)
+	#define JAVA_INTEROP_API JAVA_INTEROP_API_EXPORT
+#elif defined(MONO_DLL_IMPORT) || defined(JAVA_INTEROP_DLL_IMPORT)
+	#define JAVA_INTEROP_API JAVA_INTEROP_API_IMPORT
+#else   /* !defined(MONO_DLL_IMPORT) && !defined(MONO_DLL_EXPORT) */
+	#define JAVA_INTEROP_API
 #endif  /* MONO_DLL_EXPORT... */
 
 #ifdef __cplusplus
@@ -37,8 +37,8 @@
 
 JAVA_INTEROP_BEGIN_DECLS
 
-MONO_API    char   *java_interop_strdup (const char* value);
-MONO_API    void    java_interop_free   (void *p);
+JAVA_INTEROP_API    char   *java_interop_strdup (const char* value);
+JAVA_INTEROP_API    void    java_interop_free   (void *p);
 
 JAVA_INTEROP_END_DECLS