1 /*
2 * Copyright (c) 2016, 2020, 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/jfrJdkJfrEvent.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
71 // 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)72 extern "C" void JNICALL jfr_on_class_file_load_hook(jvmtiEnv *jvmti_env,
73 JNIEnv* jni_env,
74 jclass class_being_redefined,
75 jobject loader,
76 const char* name,
77 jobject protection_domain,
78 jint class_data_len,
79 const unsigned char* class_data,
80 jint* new_class_data_len,
81 unsigned char** new_class_data) {
82 if (class_being_redefined == NULL) {
83 return;
84 }
85 JavaThread* jt = JavaThread::thread_from_jni_environment(jni_env);
86 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));;
87 ThreadInVMfromNative tvmfn(jt);
88 JfrUpcalls::on_retransform(JfrTraceId::load_raw(class_being_redefined),
89 class_being_redefined,
90 class_data_len,
91 class_data,
92 new_class_data_len,
93 new_class_data,
94 jt);
95 }
96
97 // caller needs ResourceMark
create_classes_array(jint classes_count,TRAPS)98 static jclass* create_classes_array(jint classes_count, TRAPS) {
99 assert(classes_count > 0, "invariant");
100 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
101 ThreadInVMfromNative tvmfn(THREAD->as_Java_thread());
102 jclass* const classes = NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(THREAD, jclass, classes_count);
103 if (NULL == classes) {
104 char error_buffer[ERROR_MSG_BUFFER_SIZE];
105 jio_snprintf(error_buffer, ERROR_MSG_BUFFER_SIZE,
106 "Thread local allocation (native) of " SIZE_FORMAT " bytes failed "
107 "in retransform classes", sizeof(jclass) * classes_count);
108 log_error(jfr, system)("%s", error_buffer);
109 JfrJavaSupport::throw_out_of_memory_error(error_buffer, CHECK_NULL);
110 }
111 return classes;
112 }
113
114 // caller needs ResourceMark
log_and_throw(jvmtiError error,TRAPS)115 static void log_and_throw(jvmtiError error, TRAPS) {
116 if (!HAS_PENDING_EXCEPTION) {
117 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
118 ThreadInVMfromNative tvmfn(THREAD->as_Java_thread());
119 const char base_error_msg[] = "JfrJvmtiAgent::retransformClasses failed: ";
120 size_t length = sizeof base_error_msg; // includes terminating null
121 const char* const jvmti_error_name = JvmtiUtil::error_name(error);
122 assert(jvmti_error_name != NULL, "invariant");
123 length += strlen(jvmti_error_name);
124 char* error_msg = NEW_RESOURCE_ARRAY(char, length);
125 jio_snprintf(error_msg, length, "%s%s", base_error_msg, jvmti_error_name);
126 if (JVMTI_ERROR_INVALID_CLASS_FORMAT == error) {
127 JfrJavaSupport::throw_class_format_error(error_msg, THREAD);
128 } else {
129 JfrJavaSupport::throw_runtime_exception(error_msg, THREAD);
130 }
131 }
132 }
133
check_exception_and_log(JNIEnv * env,TRAPS)134 static void check_exception_and_log(JNIEnv* env, TRAPS) {
135 assert(env != NULL, "invariant");
136 if (env->ExceptionOccurred()) {
137 // array index out of bound
138 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
139 ThreadInVMfromNative tvmfn(THREAD->as_Java_thread());
140 log_error(jfr, system)("GetObjectArrayElement threw an exception");
141 return;
142 }
143 }
144
is_valid_jvmti_phase()145 static bool is_valid_jvmti_phase() {
146 return JvmtiEnvBase::get_phase() == JVMTI_PHASE_LIVE;
147 }
148
retransform_classes(JNIEnv * env,jobjectArray classes_array,TRAPS)149 void JfrJvmtiAgent::retransform_classes(JNIEnv* env, jobjectArray classes_array, TRAPS) {
150 assert(env != NULL, "invariant");
151 assert(classes_array != NULL, "invariant");
152 assert(is_valid_jvmti_phase(), "invariant");
153 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
154 const jint classes_count = env->GetArrayLength(classes_array);
155 if (classes_count <= 0) {
156 return;
157 }
158 ResourceMark rm(THREAD);
159 jclass* const classes = create_classes_array(classes_count, CHECK);
160 assert(classes != NULL, "invariant");
161 for (jint i = 0; i < classes_count; i++) {
162 jclass clz = (jclass)env->GetObjectArrayElement(classes_array, i);
163 check_exception_and_log(env, THREAD);
164 classes[i] = clz;
165 }
166 {
167 // inspecting the oop/klass requires a thread transition
168 ThreadInVMfromNative transition(THREAD->as_Java_thread());
169 for (jint i = 0; i < classes_count; ++i) {
170 jclass clz = classes[i];
171 if (!JdkJfrEvent::is_a(clz)) {
172 // outside the event hierarchy
173 JdkJfrEvent::tag_as_host(clz);
174 }
175 }
176 }
177 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(THREAD));
178 const jvmtiError result = jfr_jvmti_env->RetransformClasses(classes_count, classes);
179 if (result != JVMTI_ERROR_NONE) {
180 log_and_throw(result, THREAD);
181 }
182 }
183
register_callbacks(JavaThread * jt)184 static bool register_callbacks(JavaThread* jt) {
185 assert(jfr_jvmti_env != NULL, "invariant");
186 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
187 jvmtiEventCallbacks callbacks;
188 /* Set callbacks */
189 memset(&callbacks, 0, sizeof(callbacks));
190 callbacks.ClassFileLoadHook = jfr_on_class_file_load_hook;
191 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks));
192 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks");
193 return jvmti_ret_code == JVMTI_ERROR_NONE;
194 }
195
register_capabilities(JavaThread * jt)196 static bool register_capabilities(JavaThread* jt) {
197 assert(jfr_jvmti_env != NULL, "invariant");
198 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
199 jvmtiCapabilities capabilities;
200 /* Add JVMTI capabilities */
201 (void)memset(&capabilities, 0, sizeof(capabilities));
202 capabilities.can_retransform_classes = 1;
203 capabilities.can_retransform_any_class = 1;
204 const jvmtiError jvmti_ret_code = jfr_jvmti_env->AddCapabilities(&capabilities);
205 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "Add Capabilities");
206 return jvmti_ret_code == JVMTI_ERROR_NONE;
207 }
208
create_jvmti_env(JavaThread * jt)209 static jint create_jvmti_env(JavaThread* jt) {
210 assert(jfr_jvmti_env == NULL, "invariant");
211 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_native(jt));
212 extern struct JavaVM_ main_vm;
213 JavaVM* vm = &main_vm;
214 return vm->GetEnv((void **)&jfr_jvmti_env, JVMTI_VERSION);
215 }
216
unregister_callbacks(JavaThread * jt)217 static bool unregister_callbacks(JavaThread* jt) {
218 assert(jfr_jvmti_env != NULL, "invariant");
219 jvmtiEventCallbacks callbacks;
220 /* Set empty callbacks */
221 memset(&callbacks, 0, sizeof(callbacks));
222 const jvmtiError jvmti_ret_code = jfr_jvmti_env->SetEventCallbacks(&callbacks, sizeof(callbacks));
223 check_jvmti_error(jfr_jvmti_env, jvmti_ret_code, "SetEventCallbacks");
224 return jvmti_ret_code == JVMTI_ERROR_NONE;
225 }
226
JfrJvmtiAgent()227 JfrJvmtiAgent::JfrJvmtiAgent() {}
228
~JfrJvmtiAgent()229 JfrJvmtiAgent::~JfrJvmtiAgent() {
230 JavaThread* jt = JavaThread::current();
231 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
232 if (jfr_jvmti_env != NULL) {
233 ThreadToNativeFromVM transition(jt);
234 update_class_file_load_hook_event(JVMTI_DISABLE);
235 unregister_callbacks(jt);
236 jfr_jvmti_env->DisposeEnvironment();
237 jfr_jvmti_env = NULL;
238 }
239 }
240
initialize(JavaThread * jt)241 static bool initialize(JavaThread* jt) {
242 assert(jt != NULL, "invariant");
243 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(jt));
244 ThreadToNativeFromVM transition(jt);
245 if (create_jvmti_env(jt) != JNI_OK) {
246 assert(jfr_jvmti_env == NULL, "invariant");
247 return false;
248 }
249 assert(jfr_jvmti_env != NULL, "invariant");
250 if (!register_capabilities(jt)) {
251 return false;
252 }
253 if (!register_callbacks(jt)) {
254 return false;
255 }
256 return update_class_file_load_hook_event(JVMTI_ENABLE);
257 }
258
log_and_throw_illegal_state_exception(TRAPS)259 static void log_and_throw_illegal_state_exception(TRAPS) {
260 DEBUG_ONLY(JfrJavaSupport::check_java_thread_in_vm(THREAD));
261 const char* const illegal_state_msg = "An attempt was made to start JFR too early in the VM initialization sequence.";
262 log_error(jfr, system)(illegal_state_msg);
263 log_error(jfr, system)("JFR uses JVMTI RetransformClasses and requires the JVMTI state to have entered JVMTI_PHASE_LIVE.");
264 log_error(jfr, system)("Please initialize JFR in response to event JVMTI_EVENT_VM_INIT instead of JVMTI_EVENT_VM_START.");
265 JfrJavaSupport::throw_illegal_state_exception(illegal_state_msg, THREAD);
266 }
267
create()268 bool JfrJvmtiAgent::create() {
269 assert(agent == NULL, "invariant");
270 JavaThread* const jt = JavaThread::current();
271 if (!is_valid_jvmti_phase()) {
272 log_and_throw_illegal_state_exception(jt);
273 return false;
274 }
275 agent = new JfrJvmtiAgent();
276 if (agent == NULL) {
277 return false;
278 }
279 if (!initialize(jt)) {
280 delete agent;
281 agent = NULL;
282 return false;
283 }
284 return true;
285 }
286
destroy()287 void JfrJvmtiAgent::destroy() {
288 if (agent != NULL) {
289 delete agent;
290 agent = NULL;
291 }
292 }
293