/*

 * Copyright (c) 2019 SAP SE. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <stdio.h>

#include <string.h>

#include "jvmti.h"

#include "jni.h"

#ifdef __cplusplus

extern "C" {

#endif

#ifndef JNI_ENV_ARG

#ifdef __cplusplus

#define JNI_ENV_ARG(x, y) y

#define JNI_ENV_PTR(x) x

#else

#define JNI_ENV_ARG(x,y) x, y

#define JNI_ENV_PTR(x) (*x)

#endif

#endif

#define FAILED -1

static jvmtiEnv *jvmti;

static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);

static void ShowErrorMessage(jvmtiEnv *jvmti, jvmtiError errCode, const char *message) {

    char *errMsg;

    jvmtiError result;

    result = (*jvmti)->GetErrorName(jvmti, errCode, &errMsg);

    if (result == JVMTI_ERROR_NONE) {

        fprintf(stderr, "%s: %s (%d)\n", message, errMsg, errCode);

        (*jvmti)->Deallocate(jvmti, (unsigned char *)errMsg);

    } else {

        fprintf(stderr, "%s (%d)\n", message, errCode);

    }

}

JNIEXPORT jint JNICALL

Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNICALL

Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNICALL

JNI_OnLoad(JavaVM *jvm, void *reserved) {

    jint res;

    JNIEnv *env;

    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &env),

                                   JNI_VERSION_9);

    if (res != JNI_OK || env == NULL) {

        fprintf(stderr, "Error: GetEnv call failed(%d)!\n", res);

        return JNI_ERR;

    }

    return JNI_VERSION_9;

}

static

jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {

    jint res;

    jvmtiError err;

    jvmtiCapabilities caps;

    printf("Agent_OnLoad started\n");

    memset(&caps, 0, sizeof(caps));

    res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti),

                                   JVMTI_VERSION_9);

    if (res != JNI_OK || jvmti == NULL) {

        fprintf(stderr, "Error: wrong result of a valid call to GetEnv!\n");

        return JNI_ERR;

    }

    caps.can_get_owned_monitor_info = 1;

    err = (*jvmti)->AddCapabilities(jvmti, &caps);

    if (err != JVMTI_ERROR_NONE) {

        ShowErrorMessage(jvmti, err,

                         "Agent_OnLoad: error in JVMTI AddCapabilities");

        return JNI_ERR;

    }

    err = (*jvmti)->GetCapabilities(jvmti, &caps);

    if (err != JVMTI_ERROR_NONE) {

        ShowErrorMessage(jvmti, err,

                         "Agent_OnLoad: error in JVMTI GetCapabilities");

        return JNI_ERR;

    }

    if (!caps.can_get_owned_monitor_info) {

        fprintf(stderr, "Warning: GetOwnedMonitorInfo is not implemented\n");

        return JNI_ERR;

    }

    printf("Agent_OnLoad finished\n");

    return JNI_OK;

}

JNIEXPORT jint JNICALL

Java_GetOwnedMonitorInfoWithEATest_getOwnedMonitorInfo(JNIEnv *env, jclass cls, jobject targetThread, jobjectArray resOwnedMonitors) {

    jvmtiError err;

    jvmtiThreadInfo threadInfo;

    jint monitorCount;

    jobject* monitors;

    jint idx;

    err = (*jvmti)->GetThreadInfo(jvmti, targetThread, &threadInfo);

    if (err != JVMTI_ERROR_NONE) {

        ShowErrorMessage(jvmti, err,

                "getOwnedMonitorsFor: error in JVMTI GetThreadInfo");

        return FAILED;

    }

    err = (*jvmti)->GetOwnedMonitorInfo(jvmti, targetThread, &monitorCount, &monitors);

    if (err != JVMTI_ERROR_NONE) {

        ShowErrorMessage(jvmti, err,

                "getOwnedMonitorsFor: error in JVMTI GetOwnedMonitorInfo");

        return FAILED;

    }

    printf("getOwnedMonitorsFor: %s owns %d monitor(s)\n", threadInfo.name, monitorCount);

    for (idx = 0; idx < monitorCount; idx++) {

      (*env)->SetObjectArrayElement(env, resOwnedMonitors, idx, monitors[idx]);

    }

    (*jvmti)->Deallocate(jvmti, (unsigned char *) monitors);

    (*jvmti)->Deallocate(jvmti, (unsigned char *) threadInfo.name);

    return monitorCount;

}

#ifdef __cplusplus

}

#endif