1 /*
   2  * Copyright (c) 2007, 2018, 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 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <jni.h>
  27 #include <jvmti.h>
  28 #include <aod.h>
  29 #include <jvmti_aod.h>
  30 
  31 extern "C" {
  32 
  33 /*
  34  * Expected agent work scenario:
  35  *  - receive ClassFileLoadHook event for class 'ClassToRedefine'
  36  *  - receive ClassLoad event for class 'ClassToRedefine' and redefine class from ClassLoad event handler
  37  *  - receive one more ClassFileLoadHook event for class 'ClassToRedefine'
  38  *  - receive ClassPrepare event for class 'ClassToRedefine' and finish work
  39  */
  40 
  41 #define REDEFINED_CLASS_NAME "Lnsk/jvmti/AttachOnDemand/attach002/ClassToRedefine;"
  42 #define REDEFINED_CLASS_FILE_NAME "nsk/jvmti/AttachOnDemand/attach002/ClassToRedefine"
  43 
  44 // class name in the ClassFileLoadHook callback
  45 #define REDEFINED_CLASS_NAME_INTERNAL "nsk/jvmti/AttachOnDemand/attach002/ClassToRedefine"
  46 
  47 static Options* options = NULL;
  48 static const char* agentName;
  49 
  50 static volatile jboolean agentGotCapabilities = JNI_FALSE;
  51 
  52 static jvmtiEvent testEvents[] = {
  53         JVMTI_EVENT_CLASS_LOAD,
  54         JVMTI_EVENT_CLASS_PREPARE,
  55         JVMTI_EVENT_CLASS_FILE_LOAD_HOOK};
  56 
  57 static const int testEventsNumber = 3;
  58 
  59 static volatile int classLoadReceived = 0;
  60 static volatile int classFileLoadHookReceived = 0;
  61 
  62 JNIEXPORT jboolean JNICALL
  63 Java_nsk_jvmti_AttachOnDemand_attach002_attach002Target_agentGotCapabilities(JNIEnv * jni,
  64         jclass klass, jobject obj) {
  65     return agentGotCapabilities;
  66 }
  67 
  68 #define ATTACH002_TARGET_APP_CLASS_NAME "nsk/jvmti/AttachOnDemand/attach002/attach002Target"
  69 
  70 int registerNativeMethods(JNIEnv* jni) {
  71     jclass appClass;
  72     JNINativeMethod nativeMethods[] = {
  73             {(char*) "agentGotCapabilities", (char*) "()Z", (void*) Java_nsk_jvmti_AttachOnDemand_attach002_attach002Target_agentGotCapabilities}};
  74     jint nativeMethodsNumber = 1;
  75 
  76     if (!NSK_JNI_VERIFY(jni, (appClass =
  77         jni->FindClass(ATTACH002_TARGET_APP_CLASS_NAME)) != NULL)) {
  78         return NSK_FALSE;
  79     }
  80 
  81     if (!NSK_JNI_VERIFY(jni,
  82             (jni->RegisterNatives(appClass, nativeMethods, nativeMethodsNumber) == 0))) {
  83         return NSK_FALSE;
  84     }
  85 
  86     return NSK_TRUE;
  87 }
  88 
  89 void JNICALL  classLoadHandler(
  90         jvmtiEnv *jvmti,
  91         JNIEnv* jni,
  92         jthread thread,
  93         jclass klass) {
  94     char className[MAX_STRING_LENGTH];
  95 
  96     if (!nsk_jvmti_aod_getClassName(jvmti, klass, className)) {
  97         nsk_jvmti_aod_disableEventsAndFinish(agentName, testEvents, testEventsNumber, 0, jvmti, jni);
  98         return;
  99     }
 100 
 101     NSK_DISPLAY2("%s: ClassLoad event was received for class '%s'\n", agentName, className);
 102 
 103     if (!strcmp(className, REDEFINED_CLASS_NAME)) {
 104 
 105         classLoadReceived = 1;
 106 
 107         NSK_DISPLAY1("%s: redefining class\n", agentName);
 108 
 109         if (!NSK_VERIFY(nsk_jvmti_aod_redefineClass(options, jvmti, klass, REDEFINED_CLASS_FILE_NAME))) {
 110             NSK_COMPLAIN1("%s: failed to redefine class\n", agentName);
 111             nsk_jvmti_aod_disableEventsAndFinish(agentName, testEvents, testEventsNumber, 0, jvmti, jni);
 112         }
 113     }
 114 }
 115 
 116 void JNICALL classPrepareHandler(
 117         jvmtiEnv *jvmti,
 118         JNIEnv* jni,
 119         jthread thread,
 120         jclass klass) {
 121     char className[MAX_STRING_LENGTH];
 122 
 123     if (!nsk_jvmti_aod_getClassName(jvmti, klass, className)) {
 124         nsk_jvmti_aod_disableEventsAndFinish(agentName, testEvents, testEventsNumber, 0, jvmti, jni);
 125         return;
 126     }
 127 
 128     NSK_DISPLAY2("%s: ClassPrepare event received for class '%s'\n", agentName, REDEFINED_CLASS_NAME);
 129 
 130     if (!strcmp(className, REDEFINED_CLASS_NAME)) {
 131         int success = 1;
 132 
 133         if (!classLoadReceived) {
 134             success = 0;
 135             NSK_COMPLAIN2("%s: expected ClassLoad event wasn't received for class '%s'\n", agentName, REDEFINED_CLASS_NAME);
 136         }
 137 
 138         /*
 139          * ClassFileLoadHook event should be received twice - when class is loaded and when class is redefined
 140          */
 141         if (classFileLoadHookReceived != 2) {
 142             success = 0;
 143             NSK_COMPLAIN2("%s: expected ClassFileLoadHook event wasn't received for class '%s'\n", agentName, REDEFINED_CLASS_NAME);
 144         }
 145 
 146         nsk_jvmti_aod_disableEventsAndFinish(agentName, testEvents, testEventsNumber, success, jvmti, jni);
 147     }
 148 }
 149 
 150 void JNICALL classFileLoadHoockHandler(
 151         jvmtiEnv * jvmti,
 152         JNIEnv * jni,
 153         jclass class_beeing_redefined,
 154         jobject loader,
 155         const char * name,
 156         jobject protection_domain,
 157         jint class_data_len,
 158         const unsigned char * class_data,
 159         jint * new_class_data_len,
 160         unsigned char** new_class_data) {
 161 
 162     if (name != NULL) {
 163         NSK_DISPLAY2("%s: ClassFileLoadHook event received for class '%s'\n", agentName, name);
 164         if (!strcmp(name, REDEFINED_CLASS_NAME_INTERNAL)) {
 165             classFileLoadHookReceived++;
 166         }
 167     } else {
 168         NSK_DISPLAY1("%s: ClassFileLoadHook event received for class with NULL name\n", agentName);
 169     }
 170 }
 171 
 172 #ifdef STATIC_BUILD
 173 JNIEXPORT jint JNI_OnLoad_attach002Agent00(JavaVM *jvm, char *options, void *reserved) {
 174     return JNI_VERSION_1_8;
 175 }
 176 #endif
 177 
 178 JNIEXPORT jint JNICALL
 179 #ifdef STATIC_BUILD
 180 Agent_OnAttach_attach002Agent00(JavaVM *vm, char *optionsString, void *reserved)
 181 #else
 182 Agent_OnAttach(JavaVM *vm, char *optionsString, void *reserved)
 183 #endif
 184 {
 185     jvmtiEventCallbacks eventCallbacks;
 186     jvmtiCapabilities caps;
 187     jvmtiEnv* jvmti = NULL;
 188     JNIEnv* jni = NULL;
 189 
 190     if (!NSK_VERIFY((options = (Options*) nsk_aod_createOptions(optionsString)) != NULL))
 191         return JNI_ERR;
 192 
 193     agentName = nsk_aod_getOptionValue(options, NSK_AOD_AGENT_NAME_OPTION);
 194 
 195     if ((jni = (JNIEnv*) nsk_aod_createJNIEnv(vm)) == NULL)
 196         return NSK_FALSE;
 197 
 198     if (!NSK_VERIFY((jvmti = nsk_jvmti_createJVMTIEnv(vm, reserved)) != NULL))
 199         return JNI_ERR;
 200 
 201     if (!NSK_VERIFY(registerNativeMethods(jni))) {
 202         return JNI_ERR;
 203     }
 204 
 205     memset(&caps, 0, sizeof(caps));
 206     caps.can_generate_all_class_hook_events = 1;
 207     caps.can_redefine_classes = 1;
 208     if (!NSK_JVMTI_VERIFY(jvmti->AddCapabilities(&caps))) {
 209         /*
 210          * If VM is run with -Xshare:on agent can't get required capabilities (see 6718407)
 211          */
 212         NSK_DISPLAY1("%s: warning: agent failed to get required capabilities, agent finishing\n", agentName);
 213 
 214         if (!NSK_VERIFY(nsk_aod_agentLoaded(jni, agentName)))
 215             return JNI_ERR;
 216 
 217         nsk_aod_agentFinished(jni, agentName, 1);
 218     } else {
 219         agentGotCapabilities = JNI_TRUE;
 220 
 221         memset(&eventCallbacks,0, sizeof(eventCallbacks));
 222         eventCallbacks.ClassLoad = classLoadHandler;
 223         eventCallbacks.ClassPrepare = classPrepareHandler;
 224         eventCallbacks.ClassFileLoadHook = classFileLoadHoockHandler;
 225         if (!NSK_JVMTI_VERIFY(jvmti->SetEventCallbacks(&eventCallbacks, sizeof(eventCallbacks)))) {
 226             return JNI_ERR;
 227         }
 228 
 229         if (!(nsk_jvmti_aod_enableEvents(jvmti, testEvents, testEventsNumber))) {
 230             return JNI_ERR;
 231         }
 232 
 233         NSK_DISPLAY1("%s: initialization was done\n", agentName);
 234 
 235         if (!NSK_VERIFY(nsk_aod_agentLoaded(jni, agentName)))
 236             return JNI_ERR;
 237     }
 238 
 239     return JNI_OK;
 240 }
 241 
 242 }