Add compatibility with Oracle's JVM (#30)

* Add compatibility with Oracle's JVM

* do the fix a bit differently

* fix minor issue

---------

Co-authored-by: rdbo <rdbodev@gmail.com>

Author: nbs32k

src/jnihook.cpp

@@ -476,7 +476,7 @@ JNIHook_Init(JavaVM *jvm)
 
         // Force AllowRedefinitionToAddDeleteMethods
         auto jvm_flag_type_result = VMType::from_static("JVMFlag");
-        if (!jvm_flag_type_result) {
+        if (!jvm_flag_type_result && !(jvm_flag_type_result = VMType::from_static("Flag"))) {
                 LOG("Failed to parse VMStructs\n");
                 return JNIHOOK_ERR_UNKNOWN;
         }
@@ -496,7 +496,7 @@ JNIHook_Init(JavaVM *jvm)
         auto flags_buf = *(unsigned char **)flagsField; // flagTable
         auto numFlags = *numFlagsField;
         for (size_t i = 0; i < numFlags; ++i) {
-                auto flag = VMType::from_instance("JVMFlag", &flags_buf[i * jvm_flag_size]);
+                auto flag = VMType::from_instance(jvm_flag_type.get_type_name().c_str(), &flags_buf[i * jvm_flag_size]);
                 auto name_addr = flag->get_field<void *>("_name").value();
                 auto name = (char *)*name_addr;
                 LOG("FLAG: %s\n", name);

src/jvm.cpp

@@ -81,6 +81,7 @@ std::optional<VMType> VMType::from_static(const char *typeName)
 
         VMType vmtype;
         vmtype.instance = NULL;
+        vmtype.type_name = std::string(typeName);
         vmtype.type_entry = type.value();
         vmtype.fields = fields;
 

src/jvm.hpp

@@ -80,6 +80,7 @@ class VMTypes {
 
 class VMType {
 private:
+	std::string type_name;
 	VMTypeEntry *type_entry;
 	std::optional<std::reference_wrapper<VMTypes::struct_entry_t>> fields;
 	void *instance; // pointer to instantiated VM type
@@ -119,6 +120,11 @@ class VMType {
 		return reinterpret_cast<T *>(fieldAddress.value());
 	}
 
+	const std::string &get_type_name()
+	{
+		return this->type_name;
+	}
+
 	inline void *get_instance()
 	{
 		return this->instance;