test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadEventTest/libVThreadEventTest.cpp

@@ -63,10 +63,15 @@
  JNIEXPORT jint JNICALL
  Agent_OnAttach(JavaVM *vm, char *options, void *reserved) {
    jvmtiEventCallbacks callbacks;
    jvmtiCapabilities caps;
    jvmtiError err;
+   JNIEnv *env;
+   jsize nVMs;
+   jint res;
+   jclass clazz;
+   jmethodID mid;
  
    LOG("Agent_OnAttach started\n");
    if (vm->GetEnv(reinterpret_cast<void **>(&jvmti), JVMTI_VERSION) != JNI_OK || !jvmti) {
      LOG("Could not initialize JVMTI env\n");
      return JNI_ERR;

@@ -95,10 +100,45 @@
  
    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, nullptr);
    check_jvmti_error(err, "SetEventNotificationMode for VirtualThreadUnmount");
  
    LOG("vthread events enabled\n");
+ 
+   // call VThreadEventTest.agentStarted to notify test that agent has started
+ 
+   res = JNI_GetCreatedJavaVMs(&vm, 1, &nVMs);
+   if (res != JNI_OK) {
+       LOG("JNI_GetCreatedJavaVMs failed: %d\n", res);
+       return JNI_ERR;
+   }
+ 
+   res = vm->GetEnv((void **) &env, JNI_VERSION_21);
+   if (res != JNI_OK) {
+     LOG("GetEnv failed: %d\n", res);
+     return JNI_ERR;
+   }
+ 
+   clazz = env->FindClass("VThreadEventTest");
+   if (clazz == NULL) {
+       LOG("FindClass failed\n");
+       return JNI_ERR;
+   }
+ 
+   mid = env->GetStaticMethodID(clazz, "agentStarted", "()V");
+   if (mid == NULL) {
+       LOG("GetStaticMethodID failed\n");
+       return JNI_ERR;
+   }
+ 
+   env->CallStaticVoidMethod(clazz, mid);
+   if (env->ExceptionOccurred()) {
+       LOG("CallStaticVoidMethod failed\n");
+       return JNI_ERR;
+   }
+ 
+   LOG("Agent_OnAttach done\n");
+ 
    return JVMTI_ERROR_NONE;
  }
  
  } // extern "C"