Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * 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_1_8;

 }

 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_1_2);

     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