1 /*
2  * Copyright (C) 2016 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ART_OPENJDKJVMTI_EVENTS_H_
18 #define ART_OPENJDKJVMTI_EVENTS_H_
19 
20 #include <bitset>
21 #include <vector>
22 
23 #include <android-base/logging.h>
24 
25 #include "base/macros.h"
26 #include "base/mutex.h"
27 #include "jvmti.h"
28 #include "thread.h"
29 
30 namespace openjdkjvmti {
31 
32 struct ArtJvmTiEnv;
33 class JvmtiAllocationListener;
34 class JvmtiDdmChunkListener;
35 class JvmtiGcPauseListener;
36 class JvmtiMethodTraceListener;
37 class JvmtiMonitorListener;
38 
39 // an enum for ArtEvents. This differs from the JVMTI events only in that we distinguish between
40 // retransformation capable and incapable loading
41 enum class ArtJvmtiEvent : jint {
42     kMinEventTypeVal = JVMTI_MIN_EVENT_TYPE_VAL,
43     kVmInit = JVMTI_EVENT_VM_INIT,
44     kVmDeath = JVMTI_EVENT_VM_DEATH,
45     kThreadStart = JVMTI_EVENT_THREAD_START,
46     kThreadEnd = JVMTI_EVENT_THREAD_END,
47     kClassFileLoadHookNonRetransformable = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
48     kClassLoad = JVMTI_EVENT_CLASS_LOAD,
49     kClassPrepare = JVMTI_EVENT_CLASS_PREPARE,
50     kVmStart = JVMTI_EVENT_VM_START,
51     kException = JVMTI_EVENT_EXCEPTION,
52     kExceptionCatch = JVMTI_EVENT_EXCEPTION_CATCH,
53     kSingleStep = JVMTI_EVENT_SINGLE_STEP,
54     kFramePop = JVMTI_EVENT_FRAME_POP,
55     kBreakpoint = JVMTI_EVENT_BREAKPOINT,
56     kFieldAccess = JVMTI_EVENT_FIELD_ACCESS,
57     kFieldModification = JVMTI_EVENT_FIELD_MODIFICATION,
58     kMethodEntry = JVMTI_EVENT_METHOD_ENTRY,
59     kMethodExit = JVMTI_EVENT_METHOD_EXIT,
60     kNativeMethodBind = JVMTI_EVENT_NATIVE_METHOD_BIND,
61     kCompiledMethodLoad = JVMTI_EVENT_COMPILED_METHOD_LOAD,
62     kCompiledMethodUnload = JVMTI_EVENT_COMPILED_METHOD_UNLOAD,
63     kDynamicCodeGenerated = JVMTI_EVENT_DYNAMIC_CODE_GENERATED,
64     kDataDumpRequest = JVMTI_EVENT_DATA_DUMP_REQUEST,
65     kMonitorWait = JVMTI_EVENT_MONITOR_WAIT,
66     kMonitorWaited = JVMTI_EVENT_MONITOR_WAITED,
67     kMonitorContendedEnter = JVMTI_EVENT_MONITOR_CONTENDED_ENTER,
68     kMonitorContendedEntered = JVMTI_EVENT_MONITOR_CONTENDED_ENTERED,
69     kResourceExhausted = JVMTI_EVENT_RESOURCE_EXHAUSTED,
70     kGarbageCollectionStart = JVMTI_EVENT_GARBAGE_COLLECTION_START,
71     kGarbageCollectionFinish = JVMTI_EVENT_GARBAGE_COLLECTION_FINISH,
72     kObjectFree = JVMTI_EVENT_OBJECT_FREE,
73     kVmObjectAlloc = JVMTI_EVENT_VM_OBJECT_ALLOC,
74     kClassFileLoadHookRetransformable = JVMTI_MAX_EVENT_TYPE_VAL + 1,
75     kDdmPublishChunk = JVMTI_MAX_EVENT_TYPE_VAL + 2,
76     kMaxEventTypeVal = kDdmPublishChunk,
77 };
78 
79 using ArtJvmtiEventDdmPublishChunk = void (*)(jvmtiEnv *jvmti_env,
80                                               JNIEnv* jni_env,
81                                               jint data_type,
82                                               jint data_len,
83                                               const jbyte* data);
84 
85 struct ArtJvmtiEventCallbacks : jvmtiEventCallbacks {
ArtJvmtiEventCallbacksArtJvmtiEventCallbacks86   ArtJvmtiEventCallbacks() : DdmPublishChunk(nullptr) {
87     memset(this, 0, sizeof(jvmtiEventCallbacks));
88   }
89 
90   // Copies extension functions from other callback struct if it exists. There must not have been
91   // any modifications to this struct when it is called.
92   void CopyExtensionsFrom(const ArtJvmtiEventCallbacks* cb);
93 
94   jvmtiError Set(jint index, jvmtiExtensionEvent cb);
95 
96   ArtJvmtiEventDdmPublishChunk DdmPublishChunk;
97 };
98 
99 bool IsExtensionEvent(jint e);
100 bool IsExtensionEvent(ArtJvmtiEvent e);
101 
102 // Convert a jvmtiEvent into a ArtJvmtiEvent
103 ALWAYS_INLINE static inline ArtJvmtiEvent GetArtJvmtiEvent(ArtJvmTiEnv* env, jvmtiEvent e);
104 
GetJvmtiEvent(ArtJvmtiEvent e)105 static inline jvmtiEvent GetJvmtiEvent(ArtJvmtiEvent e) {
106   if (UNLIKELY(e == ArtJvmtiEvent::kClassFileLoadHookRetransformable)) {
107     return JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
108   } else {
109     return static_cast<jvmtiEvent>(e);
110   }
111 }
112 
113 struct EventMask {
114   static constexpr size_t kEventsSize =
115       static_cast<size_t>(ArtJvmtiEvent::kMaxEventTypeVal) -
116       static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal) + 1;
117   std::bitset<kEventsSize> bit_set;
118 
EventIsInRangeEventMask119   static bool EventIsInRange(ArtJvmtiEvent event) {
120     return event >= ArtJvmtiEvent::kMinEventTypeVal && event <= ArtJvmtiEvent::kMaxEventTypeVal;
121   }
122 
123   void Set(ArtJvmtiEvent event, bool value = true) {
124     DCHECK(EventIsInRange(event));
125     bit_set.set(static_cast<size_t>(event) - static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal),
126                 value);
127   }
128 
TestEventMask129   bool Test(ArtJvmtiEvent event) const {
130     DCHECK(EventIsInRange(event));
131     return bit_set.test(
132         static_cast<size_t>(event) - static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal));
133   }
134 };
135 
136 struct EventMasks {
137   // The globally enabled events.
138   EventMask global_event_mask;
139 
140   // The per-thread enabled events.
141 
142   // It is not enough to store a Thread pointer, as these may be reused. Use the pointer and the
143   // thread id.
144   // Note: We could just use the tid like tracing does.
145   using UniqueThread = std::pair<art::Thread*, uint32_t>;
146   // TODO: Native thread objects are immovable, so we can use them as keys in an (unordered) map,
147   //       if necessary.
148   std::vector<std::pair<UniqueThread, EventMask>> thread_event_masks;
149 
150   // A union of the per-thread events, for fast-pathing.
151   EventMask unioned_thread_event_mask;
152 
153   EventMask& GetEventMask(art::Thread* thread);
154   EventMask* GetEventMaskOrNull(art::Thread* thread);
155   // Circular dependencies mean we cannot see the definition of ArtJvmTiEnv so the mutex is simply
156   // asserted in the function.
157   // Note that the 'env' passed in must be the same env this EventMasks is associated with.
158   void EnableEvent(ArtJvmTiEnv* env, art::Thread* thread, ArtJvmtiEvent event);
159       // REQUIRES(env->event_info_mutex_);
160   // Circular dependencies mean we cannot see the definition of ArtJvmTiEnv so the mutex is simply
161   // asserted in the function.
162   // Note that the 'env' passed in must be the same env this EventMasks is associated with.
163   void DisableEvent(ArtJvmTiEnv* env, art::Thread* thread, ArtJvmtiEvent event);
164       // REQUIRES(env->event_info_mutex_);
165   bool IsEnabledAnywhere(ArtJvmtiEvent event);
166   // Make any changes to event masks needed for the given capability changes. If caps_added is true
167   // then caps is all the newly set capabilities of the jvmtiEnv. If it is false then caps is the
168   // set of all capabilities that were removed from the jvmtiEnv.
169   void HandleChangedCapabilities(const jvmtiCapabilities& caps, bool caps_added);
170 };
171 
172 namespace impl {
173 template <ArtJvmtiEvent kEvent> struct EventHandlerFunc { };
174 }  // namespace impl
175 
176 // Helper class for event handling.
177 class EventHandler {
178  public:
179   EventHandler();
180   ~EventHandler();
181 
182   // do cleanup for the event handler.
183   void Shutdown();
184 
185   // Register an env. It is assumed that this happens on env creation, that is, no events are
186   // enabled, yet.
187   void RegisterArtJvmTiEnv(ArtJvmTiEnv* env) REQUIRES(!envs_lock_);
188 
189   // Remove an env.
190   void RemoveArtJvmTiEnv(ArtJvmTiEnv* env) REQUIRES(!envs_lock_);
191 
IsEventEnabledAnywhere(ArtJvmtiEvent event)192   bool IsEventEnabledAnywhere(ArtJvmtiEvent event) const {
193     if (!EventMask::EventIsInRange(event)) {
194       return false;
195     }
196     return global_mask.Test(event);
197   }
198 
199   jvmtiError SetEvent(ArtJvmTiEnv* env,
200                       art::Thread* thread,
201                       ArtJvmtiEvent event,
202                       jvmtiEventMode mode)
203       REQUIRES(!envs_lock_);
204 
205   // Dispatch event to all registered environments. Since this one doesn't have a JNIEnv* it doesn't
206   // matter if it has the mutator_lock.
207   template <ArtJvmtiEvent kEvent, typename ...Args>
208   ALWAYS_INLINE
209   inline void DispatchEvent(art::Thread* thread, Args... args) const
210       REQUIRES(!envs_lock_);
211 
212   // Dispatch event to all registered environments stashing exceptions as needed. This works since
213   // JNIEnv* is always the second argument if it is passed to an event. Needed since C++ does not
214   // allow partial template function specialization.
215   //
216   // We need both of these since we want to make sure to push a stack frame when it is possible for
217   // the event to allocate local references.
218   template <ArtJvmtiEvent kEvent, typename ...Args>
219   ALWAYS_INLINE
220   inline void DispatchEvent(art::Thread* thread, JNIEnv* jnienv, Args... args) const
221       REQUIRES(!envs_lock_);
222 
223   // Tell the event handler capabilities were added/lost so it can adjust the sent events.If
224   // caps_added is true then caps is all the newly set capabilities of the jvmtiEnv. If it is false
225   // then caps is the set of all capabilities that were removed from the jvmtiEnv.
226   ALWAYS_INLINE
227   inline void HandleChangedCapabilities(ArtJvmTiEnv* env,
228                                         const jvmtiCapabilities& caps,
229                                         bool added)
230       REQUIRES(!envs_lock_);
231 
232   // Dispatch event to the given environment, only.
233   template <ArtJvmtiEvent kEvent, typename ...Args>
234   ALWAYS_INLINE
235   inline void DispatchEventOnEnv(ArtJvmTiEnv* env,
236                                  art::Thread* thread,
237                                  JNIEnv* jnienv,
238                                  Args... args) const
239       REQUIRES(!envs_lock_);
240 
241   // Dispatch event to the given environment, only.
242   template <ArtJvmtiEvent kEvent, typename ...Args>
243   ALWAYS_INLINE
244   inline void DispatchEventOnEnv(ArtJvmTiEnv* env, art::Thread* thread, Args... args) const
245       REQUIRES(!envs_lock_);
246 
247  private:
248   void SetupTraceListener(JvmtiMethodTraceListener* listener, ArtJvmtiEvent event, bool enable);
249 
250   template <ArtJvmtiEvent kEvent, typename ...Args>
251   ALWAYS_INLINE
252   inline std::vector<impl::EventHandlerFunc<kEvent>> CollectEvents(art::Thread* thread,
253                                                                    Args... args) const
254       REQUIRES(!envs_lock_);
255 
256   template <ArtJvmtiEvent kEvent>
257   ALWAYS_INLINE
258   inline bool ShouldDispatchOnThread(ArtJvmTiEnv* env, art::Thread* thread) const;
259 
260   template <ArtJvmtiEvent kEvent, typename ...Args>
261   ALWAYS_INLINE
262   static inline void ExecuteCallback(impl::EventHandlerFunc<kEvent> handler,
263                                      JNIEnv* env,
264                                      Args... args)
265       REQUIRES(!envs_lock_);
266 
267   template <ArtJvmtiEvent kEvent, typename ...Args>
268   ALWAYS_INLINE
269   static inline void ExecuteCallback(impl::EventHandlerFunc<kEvent> handler, Args... args)
270       REQUIRES(!envs_lock_);
271 
272   // Public for use to collect dispatches
273   template <ArtJvmtiEvent kEvent, typename ...Args>
274   ALWAYS_INLINE
275   inline bool ShouldDispatch(ArtJvmTiEnv* env, art::Thread* thread, Args... args) const;
276 
277   ALWAYS_INLINE
278   inline bool NeedsEventUpdate(ArtJvmTiEnv* env,
279                                const jvmtiCapabilities& caps,
280                                bool added);
281 
282   // Recalculates the event mask for the given event.
283   ALWAYS_INLINE
284   inline void RecalculateGlobalEventMask(ArtJvmtiEvent event) REQUIRES(!envs_lock_);
285   ALWAYS_INLINE
286   inline void RecalculateGlobalEventMaskLocked(ArtJvmtiEvent event) REQUIRES_SHARED(envs_lock_);
287 
288   template <ArtJvmtiEvent kEvent>
289   ALWAYS_INLINE inline void DispatchClassFileLoadHookEvent(art::Thread* thread,
290                                                            JNIEnv* jnienv,
291                                                            jclass class_being_redefined,
292                                                            jobject loader,
293                                                            const char* name,
294                                                            jobject protection_domain,
295                                                            jint class_data_len,
296                                                            const unsigned char* class_data,
297                                                            jint* new_class_data_len,
298                                                            unsigned char** new_class_data) const
299       REQUIRES(!envs_lock_);
300 
301   void HandleEventType(ArtJvmtiEvent event, bool enable);
302   void HandleLocalAccessCapabilityAdded();
303   void HandleBreakpointEventsChanged(bool enable);
304 
305   bool OtherMonitorEventsEnabledAnywhere(ArtJvmtiEvent event);
306 
307   // List of all JvmTiEnv objects that have been created, in their creation order. It is a std::list
308   // since we mostly access it by iterating over the entire thing, only ever append to the end, and
309   // need to be able to remove arbitrary elements from it.
310   std::list<ArtJvmTiEnv*> envs GUARDED_BY(envs_lock_);
311 
312   // Top level lock. Nothing at all should be held when we lock this.
313   mutable art::ReaderWriterMutex envs_lock_
314       ACQUIRED_BEFORE(art::Locks::instrument_entrypoints_lock_);
315 
316   // A union of all enabled events, anywhere.
317   EventMask global_mask;
318 
319   std::unique_ptr<JvmtiAllocationListener> alloc_listener_;
320   std::unique_ptr<JvmtiDdmChunkListener> ddm_listener_;
321   std::unique_ptr<JvmtiGcPauseListener> gc_pause_listener_;
322   std::unique_ptr<JvmtiMethodTraceListener> method_trace_listener_;
323   std::unique_ptr<JvmtiMonitorListener> monitor_listener_;
324 
325   // True if frame pop has ever been enabled. Since we store pointers to stack frames we need to
326   // continue to listen to this event even if it has been disabled.
327   // TODO We could remove the listeners once all jvmtiEnvs have drained their shadow-frame vectors.
328   bool frame_pop_enabled;
329 };
330 
331 }  // namespace openjdkjvmti
332 
333 #endif  // ART_OPENJDKJVMTI_EVENTS_H_
334