/*
 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. 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 "agent_common.h"
#include "JVMTITools.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 STATUS_FAILED 2
#define PASSED 0

static jvmtiEnv *jvmti = NULL;
static jvmtiCapabilities caps;

#ifdef STATIC_BUILD
JNIEXPORT jint JNICALL Agent_OnLoad_redefclass002(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNICALL Agent_OnAttach_redefclass002(JavaVM *jvm, char *options, void *reserved) {
    return Agent_Initialize(jvm, options, reserved);
}
JNIEXPORT jint JNI_OnLoad_redefclass002(JavaVM *jvm, char *options, void *reserved) {
    return JNI_VERSION_1_8;
}
#endif
jint  Agent_Initialize(JavaVM *vm, char *options, void *reserved) {
    jint res;
    jvmtiError err;

    if ((res = JNI_ENV_PTR(vm)->GetEnv(JNI_ENV_ARG(vm, (void **) &jvmti),
            JVMTI_VERSION_1_1)) != JNI_OK) {
        printf("%s: Failed to call GetEnv: error=%d\n", __FILE__, res);
        return JNI_ERR;
    }

    err = (*jvmti)->GetPotentialCapabilities(jvmti, &caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetPotentialCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = (*jvmti)->AddCapabilities(jvmti, &caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(AddCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    err = (*jvmti)->GetCapabilities(jvmti, &caps);
    if (err != JVMTI_ERROR_NONE) {
        printf("(GetCapabilities) unexpected error: %s (%d)\n",
               TranslateError(err), err);
        return JNI_ERR;
    }

    if (!caps.can_redefine_classes) {
        printf("Warning: RedefineClasses is not implemented\n");
    }

    if (!caps.can_suspend) {
        printf("Warning: suspend/resume is not implemented\n");
    }

    return JNI_OK;
}

JNIEXPORT jint JNICALL
Java_nsk_jvmti_RedefineClasses_redefclass002_suspThread(JNIEnv *env, jclass cls, jint vrb,
        jobject susThr) {
    jvmtiError err;

    if (vrb == 1)
        printf(">>>>>>>> Invoke SuspendThread()\n");
    if ((err = ((*jvmti)->SuspendThread(jvmti, susThr))) != JVMTI_ERROR_NONE) {
        printf("%s: Failed to call SuspendThread():\n\tthe function returned error %d: %s\n",
            __FILE__, err, TranslateError(err));
        printf("\tFor more info about this error see the JVMTI spec.\n");
        return JNI_ERR;
    }
    if (vrb == 1)
        printf("<<<<<<<< SuspendThread() is successfully done\n");
    return PASSED;
}

JNIEXPORT jint JNICALL
Java_nsk_jvmti_RedefineClasses_redefclass002_resThread(JNIEnv *env, jclass cls, jint vrb,
        jobject susThr) {
    jvmtiError err;

    if (vrb == 1)
        printf(">>>>>>>> Invoke ResumeThread()\n");
    if ((err = ((*jvmti)->ResumeThread(jvmti, susThr))) != JVMTI_ERROR_NONE) {
        printf("%s: Failed to call ResumThread():\n\tthe function returned error %d: %s\n",
            __FILE__, err, TranslateError(err));
        printf("\tFor more info about this error see the JVMTI spec.\n");
        return JNI_ERR;
    }
    if (vrb == 1)
        printf("<<<<<<<< ResumeThread() is successfully done\n");
    return PASSED;
}

JNIEXPORT jint JNICALL
Java_nsk_jvmti_RedefineClasses_redefclass002_makeRedefinition(JNIEnv *env, jclass cls, jint vrb,
        jclass redefCls, jbyteArray classBytes) {
    jvmtiClassDefinition classDef;
    jvmtiError err;

    if (jvmti == NULL) {
        printf("JVMTI client was not properly loaded!\n");
        return STATUS_FAILED;
    }

    if (!caps.can_redefine_classes || !caps.can_suspend) {
        return PASSED;
    }

/* filling the structure jvmtiClassDefinition */
    classDef.klass = redefCls;
    classDef.class_byte_count =
        JNI_ENV_PTR(env)->GetArrayLength(JNI_ENV_ARG(env, classBytes));
    classDef.class_bytes = (unsigned char *)
        JNI_ENV_PTR(env)->GetByteArrayElements(JNI_ENV_ARG(env, classBytes), NULL);

    if (vrb == 1)
        printf(">>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",
            classDef.class_byte_count);
    if ((err = ((*jvmti)->RedefineClasses(jvmti, 1, &classDef))) != JVMTI_ERROR_NONE) {
        printf("%s: Failed to call RedefineClasses():\n\tthe function returned error %d: %s\n",
            __FILE__, err, TranslateError(err));
        printf("\tFor more info about this error see the JVMTI spec.\n");
        return STATUS_FAILED;
    }
    if (vrb == 1)
        printf("<<<<<<<< RedefineClasses() is successfully done\n");

    return PASSED;
}

#ifdef __cplusplus
}
#endif