/*

 * 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 PASSED 0

#define STATUS_FAILED 2

static jvmtiEnv *jvmti = NULL;

static jvmtiCapabilities caps;

static jvmtiEventCallbacks callbacks;

static jint result = PASSED;

static jboolean printdump = JNI_FALSE;

static jmethodID mid = NULL;

static jint bpeakpointsExpected = 0;

static jint bpeakpointsCount = 0;

static jlocation loc = 0;

static jbyteArray classBytes;

static jint magicNumber;

void check(jvmtiEnv *jvmti_env, jthread thr, jclass cls, jmethodID mid, jint i) {

    jvmtiError err;

    char *sigClass, *name, *sig, *generic;

    jvmtiLocalVariableEntry *table = NULL;

    jint entryCount = 0;

    jint varValue = -1;

    jint j;

    err = jvmti_env->GetClassSignature(cls, &sigClass, &generic);

    if (err != JVMTI_ERROR_NONE) {

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

               i, TranslateError(err), err);

        result = STATUS_FAILED;

    }

    err = jvmti_env->GetMethodName(mid, &name, &sig, &generic);

    if (err != JVMTI_ERROR_NONE) {

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

               i, TranslateError(err), err);

        result = STATUS_FAILED;

    }

    err = jvmti_env->GetLocalVariableTable(mid,

        &entryCount, &table);

    if (err != JVMTI_ERROR_NONE) {

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

               i, TranslateError(err), err);

        result = STATUS_FAILED;

    }

    if (table != NULL) {

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

            if (strcmp(table[j].name, "localVar") == 0) {

                err = jvmti_env->GetLocalInt(thr, 0,

                    table[j].slot, &varValue);

                if (err != JVMTI_ERROR_NONE) {

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

                           i, TranslateError(err), err);

                    result = STATUS_FAILED;

                }

            }

        }

    }

    if (printdump == JNI_TRUE) {

        printf(">>> bp %d: \"%s.%s%s\"", i, sigClass, name, sig);

        printf(", localVar value: %d\n", varValue);

    }

    if (varValue != i) {

        printf("(bp %d) wrong localVar value: %d,", i, varValue);

        printf(" expected: %d\n", i);

        result = STATUS_FAILED;

    }

    if (sigClass != NULL) {

        jvmti_env->Deallocate((unsigned char*)sigClass);

    }

    if (name != NULL) {

        jvmti_env->Deallocate((unsigned char*)name);

    }

    if (sig != NULL) {

        jvmti_env->Deallocate((unsigned char*)sig);

    }

    if (table != NULL) {

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

            jvmti_env->Deallocate((unsigned char*)(table[j].name));

            jvmti_env->Deallocate((unsigned char*)(table[j].signature));

        }

        jvmti_env->Deallocate((unsigned char*)table);

    }

}

void JNICALL Breakpoint(jvmtiEnv *jvmti_env, JNIEnv *env,

        jthread thread, jmethodID method, jlocation location) {

    jvmtiError err;

    jclass klass;

    unsigned char *bytes;

    jvmtiClassDefinition classDef;

    jboolean found = JNI_FALSE;

    jint i;

    if (mid != method) {

        printf("bp: don't know where we get called from");

        result = STATUS_FAILED;

        return;

    }

    err = jvmti_env->GetMethodDeclaringClass(method, &klass);

    if (err != JVMTI_ERROR_NONE) {

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

               bpeakpointsCount, TranslateError(err), err);

        result = STATUS_FAILED;

        return;

    }

    check(jvmti_env, thread, klass, method, bpeakpointsCount);

    bpeakpointsCount++;

    classDef.klass = klass;

    for (i = 0; i < classDef.class_byte_count - 3; i++) {

        if (((jint)bytes[i+3] |

            ((jint)bytes[i+2] << 8) |

            ((jint)bytes[i+1] << 16) |

            ((jint)bytes[i] << 24)) == magicNumber) {

            found = JNI_TRUE;

            break;

        }

    }

    if (found == JNI_TRUE) {

        bytes[i] = 0;

        bytes[i+1] = 0;

        bytes[i+2] = 0;

        bytes[i+3] = (jbyte)bpeakpointsCount;

    } else {

        printf("Cannot find magic number\n");

        result = STATUS_FAILED;

        return;

    }

    classDef.class_bytes = bytes;

    err = jvmti_env->RedefineClasses(1, &classDef);

    if (err != JVMTI_ERROR_NONE) {

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

               bpeakpointsCount, TranslateError(err), err);

        result = STATUS_FAILED;

    }

    err = jvmti_env->SetBreakpoint(mid, loc);

    if (err != JVMTI_ERROR_NONE) {

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

               bpeakpointsCount, TranslateError(err), err);

        result = STATUS_FAILED;

    }

}

#ifdef STATIC_BUILD

JNIEXPORT jint JNICALL Agent_OnLoad_redefclass016(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNICALL Agent_OnAttach_redefclass016(JavaVM *jvm, char *options, void *reserved) {

    return Agent_Initialize(jvm, options, reserved);

}

JNIEXPORT jint JNI_OnLoad_redefclass016(JavaVM *jvm, char *options, void *reserved) {

    return JNI_VERSION_1_8;

}

#endif

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

    jvmtiError err;

    jint res;

    if (options != NULL && strcmp(options, "printdump") == 0) {

        printdump = JNI_TRUE;

    }

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

        printf("Wrong result of a valid call to GetEnv!\n");

        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_get_line_numbers) {

        printf("Warning: GetLineNumberTable is not implemented\n");

    }

    if (!caps.can_access_local_variables) {

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

    }

    if (caps.can_generate_breakpoint_events) {

        callbacks.Breakpoint = &Breakpoint;

        err = jvmti->SetEventCallbacks(&callbacks, sizeof(callbacks));

        if (err != JVMTI_ERROR_NONE) {

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

                   TranslateError(err), err);

            return JNI_ERR;

        }

    } else {

        printf("Warning: Breakpoint event is not implemented\n");

    }

    return JNI_OK;

}

JNIEXPORT void JNICALL

Java_nsk_jvmti_RedefineClasses_redefclass016_getReady(JNIEnv *env, jclass cls,

        jclass clazz, jbyteArray bytes, jint magic, jint line) {

    jvmtiError err;

    jvmtiLineNumberEntry *lines = NULL;

    jint i = 0, entryCount = 0;

    if (jvmti == NULL) {

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

        result = STATUS_FAILED;

        return;

    }

    if (!caps.can_redefine_classes ||

        !caps.can_generate_breakpoint_events ||

        !caps.can_get_line_numbers ||

        !caps.can_access_local_variables) return;

    if (mid == NULL) {

        printf("Cannot find Method ID for method run\n");

        result = STATUS_FAILED;

        return;

    }

    err = jvmti->GetLineNumberTable(mid, &entryCount, &lines);

    if (err != JVMTI_ERROR_NONE) {

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

               TranslateError(err), err);

        result = STATUS_FAILED;

        return;

    }

    if (lines != NULL && entryCount > 0) {

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

            if (line == lines[i].line_number) {

                loc = lines[i].start_location;

                break;

            }

        }

    }

    if (i == entryCount) {

        printf("Cannot find line number entry for %d\n", line);

        result = STATUS_FAILED;

        return;

    }

    err = jvmti->SetBreakpoint(mid, loc);

    if (err != JVMTI_ERROR_NONE) {

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

               TranslateError(err), err);

        result = STATUS_FAILED;

        return;

    }

    err = jvmti->SetEventNotificationMode(JVMTI_ENABLE,

        JVMTI_EVENT_BREAKPOINT, NULL);

    if (err != JVMTI_ERROR_NONE) {

        printf("Failed to enable BREAKPOINT event: %s (%d)\n",

               TranslateError(err), err);

        result = STATUS_FAILED;

    }

    magicNumber = magic;

    bpeakpointsExpected = 8;

}

JNIEXPORT jint JNICALL

Java_nsk_jvmti_RedefineClasses_redefclass016_check(JNIEnv *env, jclass cls) {

    if (bpeakpointsCount != bpeakpointsExpected) {

        printf("Wrong number of breakpoints: %d, expected: %d\n",

            bpeakpointsCount, bpeakpointsExpected);

        result = STATUS_FAILED;

    }

    return result;

}

}