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