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/checkpoint/types/traceid/jfrTraceId.inline.hpp"
31 #include "jfr/recorder/service/jfrOptionSet.hpp"
32 #include "jfr/support/jfrEventClass.hpp"
33 #include "logging/log.hpp"
34 #include "memory/resourceArea.hpp"
35 #include "prims/jvmtiEnvBase.hpp"
36 #include "prims/jvmtiExport.hpp"
37 #include "prims/jvmtiUtil.hpp"
38 #include "runtime/interfaceSupport.inline.hpp"
39 #include "runtime/thread.inline.hpp"
40 #include "utilities/exceptions.hpp"
41
42 static const size_t ERROR_MSG_BUFFER_SIZE = 256;
43 static JfrJvmtiAgent* agent = NULL;
44 static jvmtiEnv* jfr_jvmti_env = NULL;
45
check_jvmti_error(jvmtiEnv * jvmti,jvmtiError errnum,const char * str)46 static void check_jvmti_error(jvmtiEnv* jvmti, jvmtiError errnum, const char* str) {
47 if (errnum != JVMTI_ERROR_NONE) {
48 char* errnum_str = NULL;
49 jvmti->GetErrorName(errnum, &errnum_str);
50 log_error(jfr, system)("ERROR: JfrJvmtiAgent: " INT32_FORMAT " (%s): %s\n",
51 errnum,
52 NULL == errnum_str ? "Unknown" : errnum_str,
53 NULL == str ? "" : str);
54 }
55 }
56
set_event_notification_mode(jvmtiEventMode mode,jvmtiEvent event,jthread event_thread,...)57 static bool set_event_notification_mode(jvmtiEventMode mode,
58 jvmtiEvent event,
59 jthread event_thread,
60 ...) {
61 assert(jfr_jvmti_env != NULL, "invariant");
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 == JVMTI_ERROR_NONE;
65 }
66
update_class_file_load_hook_event(jvmtiEventMode mode)67 static bool update_class_file_load_hook_event(jvmtiEventMode mode) {
68 return set_event_notification_mode(mode, JVMTI_EVENT_CLASS_FILE_LOAD_HOOK, NULL);
69 }
70
current_java_thread()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
jfr_on_class_file_load_hook(jvmtiEnv * jvmti_env,JNIEnv * jni_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)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
create_classes_array(jint classes_count,TRAPS)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 // caller needs ResourceMark
log_and_throw(jvmtiError error,TRAPS)121 static void log_and_throw(jvmtiError error, TRAPS) {
122 if (!HAS_PENDING_EXCEPTION) {
123 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
124 ThreadInVMfromNative tvmfn((JavaThread*)THREAD);
125 const char base_error_msg[] = "JfrJvmtiAgent::retransformClasses failed: ";
126 size_t length = sizeof base_error_msg; // includes terminating null
127 const char* const jvmti_error_name = JvmtiUtil::error_name(error);
128 assert(jvmti_error_name != NULL, "invariant");
129 length += strlen(jvmti_error_name);
130 char* error_msg = NEW_RESOURCE_ARRAY(char, length);
131 jio_snprintf(error_msg, length, "%s%s", base_error_msg, jvmti_error_name);
132 if (JVMTI_ERROR_INVALID_CLASS_FORMAT == error) {
133 JfrJavaSupport::throw_class_format_error(error_msg, THREAD);
134 } else {
135 JfrJavaSupport::throw_runtime_exception(error_msg, THREAD);
136 }
137 }
138 }
139
check_exception_and_log(JNIEnv * env,TRAPS)140 static void check_exception_and_log(JNIEnv* env, TRAPS) {
141 assert(env != NULL, "invariant");
142 if (env->ExceptionOccurred()) {
143 // array index out of bound
144 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
145 ThreadInVMfromNative tvmfn((JavaThread*)THREAD);
146 log_error(jfr, system)("GetObjectArrayElement threw an exception");
147 return;
148 }
149 }
150
is_valid_jvmti_phase()151 static bool is_valid_jvmti_phase() {
152 return JvmtiEnvBase::get_phase() == JVMTI_PHASE_LIVE;
153 }
154
retransform_classes(JNIEnv * env,jobjectArray classes_array,TRAPS)155 void JfrJvmtiAgent::retransform_classes(JNIEnv* env, jobjectArray classes_array, TRAPS) {
156 assert(env != NULL, "invariant");
157 assert(classes_array != NULL, "invariant");
158 assert(is_valid_jvmti_phase(), "invariant");
159 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
160 const jint classes_count = env->GetArrayLength(classes_array);
161 if (classes_count <= 0) {
162 return;
163 }
164 ResourceMark rm(THREAD);
165 jclass* const classes = create_classes_array(classes_count, CHECK);
166 assert(classes != NULL, "invariant");
167 for (jint i = 0; i < classes_count; i++) {
168 jclass clz = (jclass)env->GetObjectArrayElement(classes_array, i);
169 check_exception_and_log(env, THREAD);
170 classes[i] = clz;
171 }
172 {
173 // inspecting the oop/klass requires a thread transition
174 ThreadInVMfromNative transition((JavaThread*)THREAD);
175 for (jint i = 0; i < classes_count; ++i) {
176 jclass clz = classes[i];
177 if (!JdkJfrEvent::is_a(clz)) {
178 // outside the event hierarchy
179 JdkJfrEvent::tag_as_host(clz);
180 }
181 }
182 }
183 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
184 const jvmtiError result = jfr_jvmti_env->RetransformClasses(classes_count, classes);
185 if (result != JVMTI_ERROR_NONE) {
186 log_and_throw(result, THREAD);
187 }
188 }
189
register_callbacks(JavaThread * jt)190 static bool register_callbacks(JavaThread* jt) {
191 assert(jfr_jvmti_env != NULL, "invariant");
192 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
193 jvmtiEventCallbacks callbacks;
194 /* Set callbacks */
195 memset(&callbacks, 0, sizeof(callbacks));
196 callbacks.ClassFileLoadHook = jfr_on_class_file_load_hook;
197 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks));
198 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks");
199 return jvmti_ret_code == JVMTI_ERROR_NONE;
200 }
201
register_capabilities(JavaThread * jt)202 static bool register_capabilities(JavaThread* jt) {
203 assert(jfr_jvmti_env != NULL, "invariant");
204 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
205 jvmtiCapabilities capabilities;
206 /* Add JVMTI capabilities */
207 (void)memset(&capabilities, 0, sizeof(capabilities));
208 capabilities.can_retransform_classes = 1;
209 capabilities.can_retransform_any_class = 1;
210 const jvmtiError jvmti_ret_code = jfr_jvmti_env->AddCapabilities(&capabilities);
211 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "Add Capabilities");
212 return jvmti_ret_code == JVMTI_ERROR_NONE;
213 }
214
create_jvmti_env(JavaThread * jt)215 static jint create_jvmti_env(JavaThread* jt) {
216 assert(jfr_jvmti_env == NULL, "invariant");
217 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
218 extern struct JavaVM_ main_vm;
219 JavaVM* vm = &main_vm;
220 return vm->GetEnv((void **)&jfr_jvmti_env, JVMTI_VERSION);
221 }
222
unregister_callbacks(JavaThread * jt)223 static bool unregister_callbacks(JavaThread* jt) {
224 assert(jfr_jvmti_env != NULL, "invariant");
225 jvmtiEventCallbacks callbacks;
226 /* Set empty callbacks */
227 memset(&callbacks, 0, sizeof(callbacks));
228 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks));
229 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks");
230 return jvmti_ret_code == JVMTI_ERROR_NONE;
231 }
232
JfrJvmtiAgent()233 JfrJvmtiAgent::JfrJvmtiAgent() {}
234
~JfrJvmtiAgent()235 JfrJvmtiAgent::~JfrJvmtiAgent() {
236 JavaThread* jt = current_java_thread();
237 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
238 if (jfr_jvmti_env != NULL) {
239 ThreadToNativeFromVM transition(jt);
240 update_class_file_load_hook_event(JVMTI_DISABLE);
241 unregister_callbacks(jt);
242 jfr_jvmti_env->DisposeEnvironment();
243 jfr_jvmti_env = NULL;
244 }
245 }
246
initialize(JavaThread * jt)247 static bool initialize(JavaThread* jt) {
248 assert(jt != NULL, "invariant");
249 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
250 ThreadToNativeFromVM transition(jt);
251 if (create_jvmti_env(jt) != JNI_OK) {
252 assert(jfr_jvmti_env == NULL, "invariant");
253 return false;
254 }
255 assert(jfr_jvmti_env != NULL, "invariant");
256 if (!register_capabilities(jt)) {
257 return false;
258 }
259 if (!register_callbacks(jt)) {
260 return false;
261 }
262 return update_class_file_load_hook_event(JVMTI_ENABLE);
263 }
264
log_and_throw_illegal_state_exception(TRAPS)265 static void log_and_throw_illegal_state_exception(TRAPS) {
266 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
267 const char* const illegal_state_msg = "An attempt was made to start JFR too early in the VM initialization sequence.";
268 log_error(jfr, system)(illegal_state_msg);
269 log_error(jfr, system)("JFR uses JVMTI RetransformClasses and requires the JVMTI state to have entered JVMTI_PHASE_LIVE.");
270 log_error(jfr, system)("Please initialize JFR in response to event JVMTI_EVENT_VM_INIT instead of JVMTI_EVENT_VM_START.");
271 JfrJavaSupport::throw_illegal_state_exception(illegal_state_msg, THREAD);
272 }
273
create()274 bool JfrJvmtiAgent::create() {
275 assert(agent == NULL, "invariant");
276 JavaThread* const jt = current_java_thread();
277 if (!is_valid_jvmti_phase()) {
278 log_and_throw_illegal_state_exception(jt);
279 return false;
280 }
281 agent = new JfrJvmtiAgent();
282 if (agent == NULL) {
283 return false;
284 }
285 if (!initialize(jt)) {
286 delete agent;
287 agent = NULL;
288 return false;
289 }
290 return true;
291 }
292
destroy()293 void JfrJvmtiAgent::destroy() {
294 if (agent != NULL) {
295 delete agent;
296 agent = NULL;
297 }
298 }
299