/*

 * 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"

extern "C" {

#define METH_NUM 4 /* overall number of methods */

#define STATUS_FAILED 2

#define PASSED 0

typedef struct {   /* local variable info */

    char *v_name;  /* a variable name */

    char *v_sign;  /* JVM type signature */

} localVar;

/* local variables of redefined methods */

static localVar constr_lv[] = { /* constructor's local variables */

    {(char*) "this", (char*) "Lnsk/jvmti/RedefineClasses/redefclass009r;"},

    {(char*) "constr_i", (char*) "I"},

    {(char*) "constr_l", (char*) "J"},

    {(char*) "constr_d", (char*) "D"},

    {(char*) "constr_f", (char*) "F"},

    {(char*) "constr_c", (char*) "C"}

};

static localVar checkIt_lv[] = { /* checkIt()'s local variables */

    {(char*) "this", (char*) "Lnsk/jvmti/RedefineClasses/redefclass009r;"},

    {(char*) "out", (char*) "Ljava/io/PrintStream;"},

    {(char*) "DEBUG_MODE", (char*) "Z"}

};

static localVar finMeth_lv[] = { /* finMethod()'s local variables */

    {(char*) "this", (char*) "Lnsk/jvmti/RedefineClasses/redefclass009r;"},

    {(char*) "fin_c", (char*) "C"},

    {(char*) "fin_i", (char*) "J"},

    {(char*) "fin_j", (char*) "I"},

    {(char*) "fin_k", (char*) "J"},

    {(char*) "fin_l", (char*) "J"},

    {(char*) "fin_f", (char*) "F"}

};

static localVar statMeth_lv[] = { /* statMethod()'s local variables */

    {(char*) "stat_x", (char*) "I"},

    {(char*) "stat_y", (char*) "I"},

    {(char*) "stat_z", (char*) "I"},

    {(char*) "stat_j", (char*) "D"},

    {(char*) "stat_i", (char*) "I"}

};

typedef struct {    /* local variables of a method */

    int inst;       /* type of a method: 0- static; 1- instance */

    char *m_name;   /* a method name */

    char *m_sign;   /* JVM signature of a method */

    int vcount;     /* overall number of local variables */

    localVar *vars;

    jmethodID mid;  /* JNI's method ID */

} methInfo;

/* list of original methods with NULL pointers to localVar */

static methInfo origMethInfo[] = {

    {1, (char*) "<init>", (char*) "()V", 1, NULL, NULL},

    {1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 4, NULL, NULL},

    {1, (char*) "finMethod", (char*) "(CJIJ)V", 5, NULL, NULL},

    {0, (char*) "statMethod", (char*) "(III)D", 3, NULL, NULL}

};

/* list of redefined methods */

static methInfo redefMethInfo[] = {

    {1, (char*) "<init>", (char*) "()V", 6, constr_lv, NULL},

    {1, (char*) "checkIt", (char*) "(Ljava/io/PrintStream;Z)I", 3, checkIt_lv, NULL},

    {1, (char*) "finMethod", (char*) "(CJIJ)V", 7, finMeth_lv, NULL},

    {0, (char*) "statMethod", (char*) "(III)D", 5, statMeth_lv, NULL}

};

static jvmtiEnv *jvmti = NULL;

static jvmtiCapabilities caps;

#ifdef STATIC_BUILD

JNIEXPORT jint JNICALL Agent_OnLoad_redefclass009(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNICALL Agent_OnAttach_redefclass009(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNI_OnLoad_redefclass009(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 = vm->GetEnv((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(&caps);

    if (err != JVMTI_ERROR_NONE) {

        printf("(GetPotentialCapabilities) unexpected error: %s (%d)\n",

               TranslateError(err), err);

        return JNI_ERR;

    }

    err = jvmti->AddCapabilities(&caps);

    if (err != JVMTI_ERROR_NONE) {

        printf("(AddCapabilities) unexpected error: %s (%d)\n",

               TranslateError(err), err);

        return JNI_ERR;

    }

    err = jvmti->GetCapabilities(&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_access_local_variables) {

        printf("Warning: Access to local variables is not implemented\n");

    }

    return JNI_OK;

}

int checkAttr(JNIEnv *env, jclass redefCls, methInfo methodsInfo[],

        jint vrb, int full) {

    jvmtiError err;

    int i, j, k;

    int totRes = PASSED;

    jint count = -1;

    jvmtiLocalVariableEntry *lv_table;

    if (!caps.can_access_local_variables) {

        return PASSED;

    }

    for (i=0; i<METH_NUM; i++) {

      /* get the JNI method ID for a method with name m_name and

         signature m_sign */

        if (methodsInfo[i].inst) { /* an instance method */

            methodsInfo[i].mid = env->GetMethodID(redefCls,

                methodsInfo[i].m_name, methodsInfo[i].m_sign);

        } else {                    /* a static method */

            methodsInfo[i].mid = env->GetStaticMethodID(redefCls,

                methodsInfo[i].m_name, methodsInfo[i].m_sign);

        }

        if (methodsInfo[i].mid == NULL) {

                __FILE__, full?" ":" original ", methodsInfo[i].inst?"instance":"static",

                methodsInfo[i].m_name, methodsInfo[i].m_sign);

            return STATUS_FAILED;

        }

        /* get the LocalVariableTable attribute */

        if ((err = (jvmti->GetLocalVariableTable(methodsInfo[i].mid,

                &count, &lv_table))) != JVMTI_ERROR_NONE) {

            printf("%s: Failed to call GetLocalVariableTable(): error=%d: %s\n",

                __FILE__, err, TranslateError(err));

            printf("\tfor the%s%s method \"%s\", signature \"%s\"\n\n",

                full?" ":" original ", methodsInfo[i].inst?"instance":"static",

                methodsInfo[i].m_name, methodsInfo[i].m_sign);

            return STATUS_FAILED;

        } else {

            if (count != methodsInfo[i].vcount) {

                    full?" ":" original ", methodsInfo[i].inst?"instance":"static",

                    methodsInfo[i].m_name, methodsInfo[i].m_sign,

                    count, methodsInfo[i].vcount);

                totRes = STATUS_FAILED;

                continue;

            }

            else if (vrb)

                    methodsInfo[i].inst?"instance":"static",

                    methodsInfo[i].m_name, methodsInfo[i].m_sign, count);

            if (full) {

                for (j=0; j<count; j++) {

                    for (k=0; k<count; k++) {

                        if (strcmp(lv_table[j].name, methodsInfo[i].vars[k].v_name) == 0) {

                            if (strcmp(lv_table[j].signature, methodsInfo[i].vars[k].v_sign) != 0) {

                                    methodsInfo[i].inst?"instance":"static",

                                    methodsInfo[i].m_name, methodsInfo[i].m_sign,

                                    lv_table[j].name, lv_table[j].signature,

                                    methodsInfo[i].vars[k].v_sign);

                                totRes = STATUS_FAILED;

                                break;

                            }

                            else if (vrb)

                                printf("\tfound var \"%s\", signature \"%s\" as expected\n",

                                    lv_table[j].name, lv_table[j].signature);

                        }

                    }

                }

            }

        }

    }

    return totRes;

}

JNIEXPORT jint JNICALL

Java_nsk_jvmti_RedefineClasses_redefclass009_checkOrigAttr(JNIEnv *env,

        jclass cls, jobject redefObj) {

    jclass redefCls = env->GetObjectClass(redefObj);

    /* check only the number of local variables */

    return checkAttr(env, redefCls, origMethInfo, 0, 0);

}

JNIEXPORT jint JNICALL

Java_nsk_jvmti_RedefineClasses_redefclass009_makeRedefinition(JNIEnv *env,

        jclass cls, jint vrb, jclass redefCls, jbyteArray classBytes) {

    jvmtiError err;

    jvmtiClassDefinition classDef;

    if (jvmti == NULL) {

        printf("JVMTI client was not properly loaded!\n");

        return STATUS_FAILED;

    }

    if (!caps.can_redefine_classes) {

        return PASSED;

    }

    /* fill the structure jvmtiClassDefinition */

    classDef.klass = redefCls;

    classDef.class_byte_count = env->GetArrayLength(classBytes);

    classDef.class_bytes = (unsigned char *) env->GetByteArrayElements(classBytes, NULL);

    if (vrb)

        printf("\n>>>>>>>> Invoke RedefineClasses():\n\tnew class byte count=%d\n",

            classDef.class_byte_count);

    if ((err = (jvmti->RedefineClasses(1, &classDef))) != JVMTI_ERROR_NONE) {

        printf("%s: Failed to call RedefineClasses(): 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)

        printf("<<<<<<<< RedefineClasses() is successfully done\n\n");

    return PASSED;

}

JNIEXPORT jint JNICALL

Java_nsk_jvmti_RedefineClasses_redefclass009_getResult(JNIEnv *env,

        jclass cls, jint vrb, jobject redefObj) {

    jclass redefCls = env->GetObjectClass(redefObj);

    return checkAttr(env, redefCls, redefMethInfo, vrb, 1);

}

}