1 /* 2 * Copyright (c) 2016, 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 25 #include "precompiled.hpp" 26 #include "jvm.h" 27 #include "jfr/instrumentation/jfrJvmtiAgent.hpp" 28 #include "jfr/jni/jfrJavaSupport.hpp" 29 #include "jfr/jni/jfrUpcalls.hpp" 30 #include "jfr/recorder/access/jfrEventClass.hpp" 31 #include "jfr/recorder/access/jfrOptionSet.hpp" 32 #include "jfr/recorder/checkpoint/constant/traceid/jfrTraceId.inline.hpp" 33 #include "jfr/utilities/jfrLog.hpp" 34 #include "memory/resourceArea.hpp" 35 #include "prims/jvmtiExport.hpp" 36 #include "runtime/interfaceSupport.hpp" 37 #include "runtime/thread.inline.hpp" 38 #include "utilities/exceptions.hpp" 39 40 static const size_t ERROR_MSG_BUFFER_SIZE = 256; 41 static JfrJvmtiAgent* agent = NULL; 42 static jvmtiEnv* jfr_jvmti_env = NULL; 43 44 static void check_jvmti_error(jvmtiEnv* jvmti, jvmtiError errnum, const char* str) { 45 if (errnum != JVMTI_ERROR_NONE) { 46 char* errnum_str = NULL; 47 jvmti->GetErrorName(errnum, &errnum_str); 48 log_error(jfr, system)("ERROR: JfrJvmtiAgent: " INT32_FORMAT " (%s): %s\n", 49 errnum, 50 NULL == errnum_str ? "Unknown" : errnum_str, 51 NULL == str ? "" : str); 52 } 53 } 54 55 static jvmtiError set_event_notification_mode(jvmtiEventMode mode, 56 jvmtiEvent event, 57 jthread event_thread, 58 ...) { 59 if (jfr_jvmti_env == NULL) { 60 return JVMTI_ERROR_NONE; 61 } 62 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventNotificationMode(mode, event, event_thread); 63 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventNotificationMode"); 64 return jvmti_ret_code; 65 } 66 67 static jvmtiError update_class_file_load_hook_event(jvmtiEventMode mode) { 68 return set_event_notification_mode(mode, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL); 69 } 70 71 static JavaThread* current_java_thread() { 72 Thread* this_thread = Thread::current(); 73 assert(this_thread != NULL && this_thread->is_Java_thread(), "invariant"); 74 return static_cast<JavaThread*>(this_thread); 75 } 76 77 // jvmti event callbacks require C linkage 78 extern "C" void JNICALL jfr_on_class_file_load_hook(jvmtiEnv *jvmti_env, 79 JNIEnv* jni_env, 80 jclass class_being_redefined, 81 jobject loader, 82 const char* name, 83 jobject protection_domain, 84 jint class_data_len, 85 const unsigned char* class_data, 86 jint* new_class_data_len, 87 unsigned char** new_class_data) { 88 if (class_being_redefined == NULL) { 89 return; 90 } 91 JavaThread* jt = JavaThread::thread_from_jni_environment(jni_env); 92 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));; 93 ThreadInVMfromNative tvmfn(jt); 94 JfrUpcalls::on_retransform(JfrTraceId::get(class_being_redefined), 95 class_being_redefined, 96 class_data_len, 97 class_data, 98 new_class_data_len, 99 new_class_data, 100 jt); 101 } 102 103 // caller needs ResourceMark 104 static jclass* create_classes_array(jint classes_count, TRAPS) { 105 assert(classes_count > 0, "invariant"); 106 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD)); 107 ThreadInVMfromNative tvmfn((JavaThread*)THREAD); 108 jclass* const classes = NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(THREAD, jclass, classes_count); 109 if (NULL == classes) { 110 char error_buffer[ERROR_MSG_BUFFER_SIZE]; 111 jio_snprintf(error_buffer, ERROR_MSG_BUFFER_SIZE, 112 "Thread local allocation (native) of " SIZE_FORMAT " bytes failed " 113 "in retransform classes", sizeof(jclass) * classes_count); 114 log_error(jfr, system)("%s", error_buffer); 115 JfrJavaSupport::throw_out_of_memory_error(error_buffer, CHECK_NULL); 116 } 117 return classes; 118 } 119 120 static void log_and_throw(TRAPS) { 121 if (!HAS_PENDING_EXCEPTION) { 122 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD)); 123 ThreadInVMfromNative tvmfn((JavaThread*)THREAD); 124 log_error(jfr, system)("JfrJvmtiAgent::retransformClasses failed"); 125 JfrJavaSupport::throw_class_format_error("JfrJvmtiAgent::retransformClasses failed", THREAD); 126 } 127 } 128 129 static void check_exception_and_log(JNIEnv* env, TRAPS) { 130 assert(env != NULL, "invariant"); 131 if (env->ExceptionOccurred()) { 132 // array index out of bound 133 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD)); 134 ThreadInVMfromNative tvmfn((JavaThread*)THREAD); 135 log_error(jfr, system)("GetObjectArrayElement threw an exception"); 136 return; 137 } 138 } 139 140 void JfrJvmtiAgent::retransform_classes(JNIEnv* env, jobjectArray classes_array, TRAPS) { 141 assert(env != NULL, "invariant"); 142 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD)); 143 if (classes_array == NULL) { 144 return; 145 } 146 const jint classes_count = env->GetArrayLength(classes_array); 147 if (classes_count <= 0) { 148 return; 149 } 150 ResourceMark rm(THREAD); 151 jclass* const classes = create_classes_array(classes_count, CHECK); 152 assert(classes != NULL, "invariant"); 153 for (jint i = 0; i < classes_count; i++) { 154 jclass clz = (jclass)env->GetObjectArrayElement(classes_array, i); 155 check_exception_and_log(env, THREAD); 156 157 // inspecting the oop/klass requires a thread transition 158 { 159 ThreadInVMfromNative transition((JavaThread*)THREAD); 160 if (JdkJfrEvent::is_a(clz)) { 161 // should have been tagged already 162 assert(JdkJfrEvent::is_subklass(clz), "invariant"); 163 } else { 164 // outside the event hierarchy 165 JdkJfrEvent::tag_as_host(clz); 166 } 167 } 168 169 classes[i] = clz; 170 } 171 if (jfr_jvmti_env->RetransformClasses(classes_count, classes) != JVMTI_ERROR_NONE) { 172 log_and_throw(THREAD); 173 } 174 } 175 176 static jvmtiError register_callbacks(JavaThread* jt) { 177 assert(jfr_jvmti_env != NULL, "invariant"); 178 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt)); 179 jvmtiEventCallbacks callbacks; 180 /* Set callbacks */ 181 memset(&callbacks, 0, sizeof(callbacks)); 182 callbacks.ClassFileLoadHook = jfr_on_class_file_load_hook; 183 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks)); 184 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks"); 185 return jvmti_ret_code; 186 } 187 188 static jvmtiError register_capabilities(JavaThread* jt) { 189 assert(jfr_jvmti_env != NULL, "invariant"); 190 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt)); 191 jvmtiCapabilities capabilities; 192 /* Add JVMTI capabilities */ 193 (void)memset(&capabilities, 0, sizeof(capabilities)); 194 capabilities.can_retransform_classes = 1; 195 capabilities.can_retransform_any_class = 1; 196 const jvmtiError jvmti_ret_code = jfr_jvmti_env->AddCapabilities(&capabilities); 197 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "Add Capabilities"); 198 return jvmti_ret_code; 199 } 200 201 static jint create_jvmti_env(JavaThread* jt) { 202 assert(jfr_jvmti_env == NULL, "invariant"); 203 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt)); 204 extern struct JavaVM_ main_vm; 205 JavaVM* vm = &main_vm; 206 return vm->GetEnv((void **)&jfr_jvmti_env, JVMTI_VERSION); 207 } 208 209 static jvmtiError unregister_callbacks(JavaThread* jt) { 210 if (jfr_jvmti_env == NULL) { 211 return JVMTI_ERROR_NONE; 212 } 213 jvmtiEventCallbacks callbacks; 214 /* Set empty callbacks */ 215 memset(&callbacks, 0, sizeof(callbacks)); 216 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks)); 217 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks"); 218 return jvmti_ret_code; 219 } 220 221 JfrJvmtiAgent::JfrJvmtiAgent() {} 222 223 JfrJvmtiAgent::~JfrJvmtiAgent() { 224 JavaThread* jt = current_java_thread(); 225 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt)); 226 ThreadToNativeFromVM transition(jt); 227 update_class_file_load_hook_event(JVMTI_DISABLE); 228 unregister_callbacks(jt); 229 if (jfr_jvmti_env != NULL) { 230 jfr_jvmti_env->DisposeEnvironment(); 231 jfr_jvmti_env = NULL; 232 } 233 agent = NULL; 234 } 235 236 static bool initialize() { 237 JavaThread* const jt = current_java_thread(); 238 assert(jt != NULL, "invariant"); 239 assert(jt->thread_state() == _thread_in_vm, "invariant"); 240 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt)); 241 ThreadToNativeFromVM transition(jt); 242 if (create_jvmti_env(jt) == JNI_ERR) { 243 assert(jfr_jvmti_env == NULL, "invariant"); 244 return false; 245 } 246 assert(jfr_jvmti_env != NULL, "invariant"); 247 if (register_capabilities(jt) != JVMTI_ERROR_NONE) { 248 return false; 249 } 250 if (register_callbacks(jt) != JVMTI_ERROR_NONE) { 251 return false; 252 } 253 if (update_class_file_load_hook_event(JVMTI_ENABLE) != JVMTI_ERROR_NONE) { 254 return false; 255 } 256 return true; 257 } 258 259 bool JfrJvmtiAgent::create() { 260 assert(jfr_jvmti_env == NULL, "invariant"); 261 agent = new JfrJvmtiAgent(); 262 if (agent == NULL) { 263 return false; 264 } 265 if (!initialize()) { 266 delete agent; 267 agent = NULL; 268 return false; 269 } 270 return true; 271 } 272 273 void JfrJvmtiAgent::destroy() { 274 if (agent != NULL) { 275 delete agent; 276 agent = NULL; 277 } 278 } 279