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 "logging/log.hpp"
34#include "memory/resourceArea.hpp"
35#include "prims/jvmtiExport.hpp"
36#include "runtime/interfaceSupport.inline.hpp"
37#include "runtime/thread.inline.hpp"
38#include "utilities/exceptions.hpp"
39
40static const size_t ERROR_MSG_BUFFER_SIZE = 256;
41static JfrJvmtiAgent* agent = NULL;
42static jvmtiEnv* jfr_jvmti_env = NULL;
43
44static 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
55static 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
67static 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
71static 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
78extern "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
104static 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
120static 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
129static 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
140void 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
176static 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
188static 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
201static 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
209static 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
221JfrJvmtiAgent::JfrJvmtiAgent() {}
222
223JfrJvmtiAgent::~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
236static 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_OK) {
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
259bool 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
273void JfrJvmtiAgent::destroy() {
274 if (agent != NULL) {
275 delete agent;
276 agent = NULL;
277 }
278}
279
280