1 /*
 2  * Copyright (c) 2024, 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 <stdio.h>
25 #include <string.h>
26 #include "jvmti.h"
27 #include "jni.h"
28 #include "jvmti_common.hpp"
29 
30 #ifdef __cplusplus
31 extern "C" {
32 #endif
33 
34 static jvmtiEnv *jvmti = nullptr;
35 
36 
37 JNIEXPORT jint JNICALL
38 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
39   jint res = jvm->GetEnv((void **) &jvmti, JVMTI_VERSION_1_1);
40   if (res != JNI_OK || jvmti == nullptr) {
41     LOG("GetEnv failed, res = %d", (int)res);
42     return JNI_ERR;
43   }
44 
45   jvmtiCapabilities caps;
46   memset(&caps, 0, sizeof(caps));
47   caps.can_get_monitor_info = 1;
48   jvmtiError err = jvmti->AddCapabilities(&caps);
49   if (err != JVMTI_ERROR_NONE) {
50     LOG("AddCapabilities failed: %s (%d)\n", TranslateError(err), err);
51     return JNI_ERR;
52   }
53 
54   return JNI_OK;
55 }
56 
57 JNIEXPORT jboolean JNICALL
58 Java_ValueGetObjectMonitorUsage_nTestGetObjectMonitorUsage(JNIEnv *jni, jclass thisClass, jobject obj) {
59   bool result = true;
60   jvmtiMonitorUsage info;
61   memset(&info, 0, sizeof(info));
62   check_jvmti_error(jvmti->GetObjectMonitorUsage(obj, &info), "GetObjectMonitorUsage");
63 
64   if (info.owner != nullptr) {
65     LOG("ERROR: owner is not nullptr\n");
66     result = false;
67   }
68   if (info.entry_count != 0) {
69     LOG("ERROR: entry_count is non-zero: %d\n", (int)info.entry_count);
70     result = false;
71   }
72   if (info.waiter_count != 0) {
73     LOG("ERROR: waiter_count is no-zero: %d\n", (int)info.waiter_count);
74     result = false;
75   }
76   if (info.notify_waiter_count != 0) {
77     LOG("ERROR: notify_waiter_count is no-zero: %d\n", (int)info.notify_waiter_count);
78     result = false;
79   }
80 
81   jvmti->Deallocate((unsigned char *)info.waiters);
82   jvmti->Deallocate((unsigned char *)info.notify_waiters);
83 
84   return result ? JNI_TRUE : JNI_FALSE;
85 }
86 
87 #ifdef __cplusplus
88 }
89 #endif
90