| /* |
| * Copyright (c) 2017, 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" |
| |
| #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 TranslateError(err) "JVMTI error" |
| |
| static jvmtiEnv *jvmti = NULL; |
| |
| static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved); |
| |
| 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) { |
| return JNI_VERSION_9; |
| } |
| |
| |
| static jint newClassDataLen = 0; |
| static unsigned char* newClassData = NULL; |
| |
| static jint |
| getBytecodes(jvmtiEnv *jvmti_env, |
| jint class_data_len, const unsigned char* class_data) { |
| int i; |
| jint res; |
| |
| newClassDataLen = class_data_len; |
| res = (*jvmti_env)->Allocate(jvmti_env, newClassDataLen, &newClassData); |
| if (res != JNI_OK) { |
| printf(" Unable to allocate bytes\n"); |
| return JNI_ERR; |
| } |
| for (i = 0; i < newClassDataLen; i++) { |
| newClassData[i] = class_data[i]; |
| // Rewrite oo in class to aa |
| if (i > 0 && class_data[i] == 'o' && class_data[i-1] == 'o') { |
| newClassData[i] = newClassData[i-1] = 'a'; |
| } |
| } |
| printf(" ... copied bytecode: %d bytes\n", (int)newClassDataLen); |
| return JNI_OK; |
| } |
| |
| |
| static void JNICALL |
| Callback_ClassFileLoadHook(jvmtiEnv *jvmti_env, JNIEnv *env, |
| jclass class_being_redefined, |
| jobject loader, const char* name, jobject protection_domain, |
| jint class_data_len, const unsigned char* class_data, |
| jint *new_class_data_len, unsigned char** new_class_data) { |
| if (name != NULL && strcmp(name, "RedefineDoubleDelete$B") == 0) { |
| if (newClassData == NULL) { |
| jint res = getBytecodes(jvmti_env, class_data_len, class_data); |
| if (res == JNI_ERR) { |
| printf(">>> ClassFileLoadHook event: class name %s FAILED\n", name); |
| return; |
| } |
| // Only change for first CFLH event. |
| *new_class_data_len = newClassDataLen; |
| *new_class_data = newClassData; |
| } |
| printf(">>> ClassFileLoadHook event: class name %s\n", name); |
| } |
| } |
| |
| static |
| jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved) { |
| jint res, size; |
| jvmtiCapabilities caps; |
| jvmtiEventCallbacks callbacks; |
| jvmtiError err; |
| |
| res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti), |
| JVMTI_VERSION_9); |
| if (res != JNI_OK || jvmti == NULL) { |
| printf(" Error: wrong result of a valid call to GetEnv!\n"); |
| return JNI_ERR; |
| } |
| |
| printf("Enabling following capabilities: can_generate_all_class_hook_events, " |
| "can_retransform_classes, can_redefine_classes"); |
| memset(&caps, 0, sizeof(caps)); |
| caps.can_generate_all_class_hook_events = 1; |
| caps.can_retransform_classes = 1; |
| caps.can_redefine_classes = 1; |
| printf("\n"); |
| |
| err = (*jvmti)->AddCapabilities(jvmti, &caps); |
| if (err != JVMTI_ERROR_NONE) { |
| printf(" Error in AddCapabilites: %s (%d)\n", TranslateError(err), err); |
| return JNI_ERR; |
| } |
| |
| size = (jint)sizeof(callbacks); |
| |
| memset(&callbacks, 0, sizeof(callbacks)); |
| callbacks.ClassFileLoadHook = Callback_ClassFileLoadHook; |
| |
| err = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, size); |
| if (err != JVMTI_ERROR_NONE) { |
| printf(" Error in SetEventCallbacks: %s (%d)\n", TranslateError(err), err); |
| return JNI_ERR; |
| } |
| |
| err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL); |
| if (err != JVMTI_ERROR_NONE) { |
| printf(" Error in SetEventNotificationMode: %s (%d)\n", TranslateError(err), err); |
| return JNI_ERR; |
| } |
| |
| return JNI_OK; |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |