1 /*
   2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 #include <stdint.h>
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include "jvmti.h"
  29 
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33 
  34 #ifndef JNI_ENV_ARG
  35 
  36 #ifdef __cplusplus
  37 #define JNI_ENV_ARG(x, y) y
  38 #define JNI_ENV_PTR(x) x
  39 #else
  40 #define JNI_ENV_ARG(x,y) x, y
  41 #define JNI_ENV_PTR(x) (*x)
  42 #endif
  43 
  44 #endif
  45 
  46 #define PASSED 0
  47 #define FAILED 2
  48 
  49 static jvmtiEnv* jvmti = NULL;
  50 
  51 static jint Agent_Initialize(JavaVM *jvm, char *options, void *reserved);
  52 
  53 JNIEXPORT jint JNICALL
  54 Agent_OnLoad(JavaVM *jvm, char *options, void *reserved) {
  55     return Agent_Initialize(jvm, options, reserved);
  56 }
  57 
  58 JNIEXPORT jint JNICALL
  59 Agent_OnAttach(JavaVM *jvm, char *options, void *reserved) {
  60     return Agent_Initialize(jvm, options, reserved);
  61 }
  62 
  63 JNIEXPORT jint JNICALL
  64 JNI_OnLoad(JavaVM *jvm, void *reserved) {
  65     return JNI_VERSION_9;
  66 }
  67 
  68 static void
  69 check_jvmti_error(jvmtiEnv *jvmti, char* fname, jvmtiError err) {
  70     if (err != JVMTI_ERROR_NONE) {
  71         printf("  ## %s error: %d\n", fname, err);
  72         fflush(0);
  73         exit(err);
  74     }
  75 }
  76 
  77 static char*
  78 get_class_signature(jvmtiEnv *jvmti, jclass klass) {
  79     char* sign = NULL;
  80     jvmtiError err = (*jvmti)->GetClassSignature(jvmti, klass, &sign, NULL);
  81 
  82     check_jvmti_error(jvmti, "GetClassSignature", err);
  83     return sign;
  84 }
  85 
  86 static jboolean
  87 is_class_status_prepared(jvmtiEnv *jvmti, jclass klass) {
  88     char* sign = get_class_signature(jvmti, klass);
  89     jint status = 0;
  90     jvmtiError err = (*jvmti)->GetClassStatus(jvmti, klass, &status);
  91 
  92     check_jvmti_error(jvmti, "GetClassStatus", err);
  93     printf("    Class %s status: 0x%08x\n", sign, status);
  94     printf("    Class %s is prepared: %d\n", sign, (status & JVMTI_CLASS_STATUS_PREPARED) != 0);
  95     fflush(0);
  96 
  97     return (status & JVMTI_CLASS_STATUS_PREPARED) != 0;
  98 }
  99 
 100 static jboolean
 101 is_class_in_loaded_classes(JNIEnv *env, jclass klass) {
 102     char* sign = get_class_signature(jvmti, klass);
 103     jint class_count = 0;
 104     jclass* classes = NULL;
 105     jvmtiError err = (*jvmti)->GetLoadedClasses(jvmti, &class_count, &classes);
 106 
 107     check_jvmti_error(jvmti, "GetLoadedClasses", err);
 108 
 109     for (int i = 0; i < class_count; i++) {
 110         jclass cls = classes[i];
 111         jboolean same = (*env)->IsSameObject(env, cls, klass);
 112         if (same) {
 113             printf("Found class %s in the list of loaded classes\n", sign);
 114             fflush(0);
 115             return JNI_TRUE;
 116         }
 117     }
 118     printf("Error: Have not found class %s in the list of loaded classes\n", sign);
 119     fflush(0);
 120     return JNI_FALSE;
 121 }
 122 
 123 static void JNICALL
 124 ClassPrepare(jvmtiEnv *jvmti, JNIEnv *env, jthread thread, jclass klass) {
 125     char* sign = get_class_signature(jvmti, klass);
 126 
 127     sign = (sign == NULL) ? "NULL" : sign;
 128 
 129     if (strcmp(sign, "LFoo2;") == 0 || strcmp(sign, "LFoo3;") == 0) {
 130         printf("ClassPrepare event for class: %s\n", sign);
 131         fflush(0);
 132     }
 133 }
 134 
 135 static jint
 136 Agent_Initialize(JavaVM *jvm, char *options, void *reserved) {
 137     jvmtiError err;
 138     jint size;
 139     jint res;
 140     jvmtiEventCallbacks callbacks;
 141 
 142     printf("Agent_Initialize started\n");
 143     fflush(0);
 144     res = JNI_ENV_PTR(jvm)->GetEnv(JNI_ENV_ARG(jvm, (void **) &jvmti), JVMTI_VERSION_9);
 145     if (res != JNI_OK || jvmti == NULL) {
 146         printf("## Agent_Initialize: Error in GetEnv: res: %d, jvmti env: %p\n", res, jvmti);
 147         return JNI_ERR;
 148     }
 149 
 150     size = (jint)sizeof(callbacks);
 151     memset(&callbacks, 0, size);
 152     callbacks.ClassPrepare = ClassPrepare;
 153 
 154     err = (*jvmti)->SetEventCallbacks(jvmti, &callbacks, size);
 155     check_jvmti_error(jvmti, "## Agent_Initialize: SetEventCallbacks", err);
 156 
 157     err = (*jvmti)->SetEventNotificationMode(jvmti, JVMTI_ENABLE, JVMTI_EVENT_CLASS_PREPARE, NULL);
 158     check_jvmti_error(jvmti, "## Agent_Initialize: SetEventNotificationMode CLASS_PREPARE", err);
 159     return JNI_OK;
 160 }
 161 
 162 JNIEXPORT jint JNICALL
 163 Java_ClassStatus_check(JNIEnv *env, jclass cls, jclass klass) {
 164     if (is_class_in_loaded_classes(env, klass) != JNI_TRUE ||
 165         is_class_status_prepared(jvmti, klass)  != JNI_TRUE) {
 166         return FAILED;
 167     }
 168     return PASSED;
 169 }
 170 
 171 #ifdef __cplusplus
 172 }
 173 #endif