1 /*
  2  * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  */
 23 
 24 #include <cstring>
 25 #include <jvmti.h>
 26 #include <atomic>
 27 #include "jvmti_common.h"
 28 
 29 extern "C" {
 30 
 31 static jvmtiEnv *jvmti = nullptr;
 32 static std::atomic<int> thread_end_cnt(0);
 33 static std::atomic<int> thread_unmount_cnt(0);
 34 static std::atomic<int> thread_mount_cnt(0);
 35 
 36 void JNICALL VirtualThreadEnd(jvmtiEnv *jvmti, JNIEnv* jni, jthread vthread) {
 37   thread_end_cnt++;
 38 }
 39 
 40 void JNICALL VirtualThreadMount(jvmtiEnv* jvmti, ...) {
 41   thread_mount_cnt++;
 42 }
 43 
 44 void JNICALL VirtualThreadUnmount(jvmtiEnv* jvmti, ...) {
 45   thread_unmount_cnt++;
 46 }
 47 
 48 JNIEXPORT jint JNICALL
 49 Java_VThreadEventTest_threadEndCount(JNIEnv* jni, jclass clazz) {
 50   return thread_end_cnt;
 51 }
 52 
 53 JNIEXPORT jint JNICALL
 54 Java_VThreadEventTest_threadMountCount(JNIEnv* jni, jclass clazz) {
 55   return thread_mount_cnt;
 56 }
 57 
 58 JNIEXPORT jint JNICALL
 59 Java_VThreadEventTest_threadUnmountCount(JNIEnv* jni, jclass clazz) {
 60   return thread_unmount_cnt;
 61 }
 62 
 63 JNIEXPORT jint JNICALL
 64 Agent_OnAttach(JavaVM *vm, char *options, void *reserved) {
 65   jvmtiEventCallbacks callbacks;
 66   jvmtiCapabilities caps;
 67   jvmtiError err;
 68 
 69   LOG("Agent_OnAttach started\n");
 70   if (vm->GetEnv(reinterpret_cast<void **>(&jvmti), JVMTI_VERSION) != JNI_OK || !jvmti) {
 71     LOG("Could not initialize JVMTI env\n");
 72     return JNI_ERR;
 73   }
 74   memset(&caps, 0, sizeof(caps));
 75   caps.can_support_virtual_threads = 1;
 76   check_jvmti_error(jvmti->AddCapabilities(&caps), "AddCapabilities");
 77 
 78   memset(&callbacks, 0, sizeof(callbacks));
 79   callbacks.VirtualThreadEnd = &VirtualThreadEnd;
 80 
 81   err = jvmti->SetEventCallbacks(&callbacks, (jint)sizeof(callbacks));
 82   check_jvmti_error(err, "SetEventCallbacks");
 83 
 84   err = set_ext_event_callback(jvmti, "VirtualThreadMount", VirtualThreadMount);
 85   check_jvmti_error(err, "SetExtEventCallback for VirtualThreadMount");
 86 
 87   err = set_ext_event_callback(jvmti, "VirtualThreadUnmount", VirtualThreadUnmount);
 88   check_jvmti_error(err, "SetExtEventCallback for VirtualThreadUnmount");
 89 
 90   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, JVMTI_EVENT_VIRTUAL_THREAD_END, nullptr);
 91   check_jvmti_error(err, "SetEventNotificationMode for VirtualThreadEnd");
 92 
 93   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_MOUNT, nullptr);
 94   check_jvmti_error(err, "SetEventNotificationMode for VirtualThreadMount");
 95 
 96   err = jvmti->SetEventNotificationMode(JVMTI_ENABLE, EXT_EVENT_VIRTUAL_THREAD_UNMOUNT, nullptr);
 97   check_jvmti_error(err, "SetEventNotificationMode for VirtualThreadUnmount");
 98 
 99   LOG("vthread events enabled\n");
100   return JVMTI_ERROR_NONE;
101 }
102 
103 } // extern "C"
104