Java example source code file (versionCheck.c)

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Java - Java tags/keywords

compile, error, jni_ok, jnicall, jniexport, jvmti, jvmti_version_mask_major, jvmti_version_mask_micro, jvmti_version_mask_minor, jvmti_version_shift_major, jvmti_version_shift_micro, jvmti_version_shift_minor, run, time

The versionCheck.c Java example source code

/*
 * Copyright (c) 2004, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "jni.h"
#include "jvmti.h"

#include "agent_util.h"

/* Create major.minor.micro version string */
static void
version_check(jint cver, jint rver)
{
    jint cmajor, cminor, cmicro;
    jint rmajor, rminor, rmicro;

    cmajor = (cver & JVMTI_VERSION_MASK_MAJOR) >> JVMTI_VERSION_SHIFT_MAJOR;
    cminor = (cver & JVMTI_VERSION_MASK_MINOR) >> JVMTI_VERSION_SHIFT_MINOR;
    cmicro = (cver & JVMTI_VERSION_MASK_MICRO) >> JVMTI_VERSION_SHIFT_MICRO;
    rmajor = (rver & JVMTI_VERSION_MASK_MAJOR) >> JVMTI_VERSION_SHIFT_MAJOR;
    rminor = (rver & JVMTI_VERSION_MASK_MINOR) >> JVMTI_VERSION_SHIFT_MINOR;
    rmicro = (rver & JVMTI_VERSION_MASK_MICRO) >> JVMTI_VERSION_SHIFT_MICRO;
    stdout_message("Compile Time JVMTI Version: %d.%d.%d (0x%08x)\n",
                        cmajor, cminor, cmicro, cver);
    stdout_message("Run Time JVMTI Version: %d.%d.%d (0x%08x)\n",
                        rmajor, rminor, rmicro, rver);
    if ( (cmajor > rmajor) || (cmajor == rmajor && cminor > rminor) ) {
        fatal_error(
            "ERROR: Compile Time JVMTI and Run Time JVMTI are incompatible\n");
    }
}

/* Callback for JVMTI_EVENT_VM_INIT */
static void JNICALL
vm_init(jvmtiEnv *jvmti, JNIEnv *env, jthread thread)
{
    jvmtiError err;
    jint       runtime_version;

    /* The exact JVMTI version doesn't have to match, however this
     *  code demonstrates how you can check that the JVMTI version seen
     *  in the jvmti.h include file matches that being supplied at runtime
     *  by the VM.
     */
    err = (*jvmti)->GetVersionNumber(jvmti, &runtime_version);
    check_jvmti_error(jvmti, err, "get version number");
    version_check(JVMTI_VERSION, runtime_version);
}

/* Agent_OnLoad() is called first, we prepare for a VM_INIT event here. */
JNIEXPORT jint JNICALL
Agent_OnLoad(JavaVM *vm, char *options, void *reserved)
{
    jint                rc;
    jvmtiError          err;
    jvmtiEventCallbacks callbacks;
    jvmtiEnv           *jvmti;

    /* Get JVMTI environment */
    rc = (*vm)->GetEnv(vm, (void **)&jvmti, JVMTI_VERSION);
    if (rc != JNI_OK) {
        fatal_error("ERROR: Unable to create jvmtiEnv, GetEnv failed, error=%d\n", rc);
        return -1;
    }

    /* Set callbacks and enable event notifications */
    memset(&callbacks, 0, sizeof(callbacks));
    callbacks.VMInit                  = &vm_init;
    err = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, sizeof(callbacks));
    check_jvmti_error(jvmti, err, "set event callbacks");
    err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE,
                        JVMTI_EVENT_VM_INIT, NULL);
    check_jvmti_error(jvmti, err, "set event notify");
    return 0;
}

/* Agent_OnUnload() is called last */
JNIEXPORT void JNICALL
Agent_OnUnload(JavaVM *vm)
{
}