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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 <unordered_map>
22 #include <vector>
23 
24 #include <android-base/logging.h>
25 #include <android-base/thread_annotations.h>
26 
27 #include "android-base/thread_annotations.h"
28 #include "base/macros.h"
29 #include "base/mutex.h"
30 #include "jvmti.h"
31 #include "managed_stack.h"
32 #include "thread.h"
33 
34 namespace openjdkjvmti {
35 
36 struct ArtJvmTiEnv;
37 class JvmtiEventAllocationListener;
38 class JvmtiDdmChunkListener;
39 class JvmtiGcPauseListener;
40 class JvmtiMethodTraceListener;
41 class JvmtiMonitorListener;
42 class JvmtiParkListener;
43 
44 // an enum for ArtEvents. This differs from the JVMTI events only in that we distinguish between
45 // retransformation capable and incapable loading
46 enum class ArtJvmtiEvent : jint {
47     kMinEventTypeVal = JVMTI_MIN_EVENT_TYPE_VAL,
48     kVmInit = JVMTI_EVENT_VM_INIT,
49     kVmDeath = JVMTI_EVENT_VM_DEATH,
50     kThreadStart = JVMTI_EVENT_THREAD_START,
51     kThreadEnd = JVMTI_EVENT_THREAD_END,
52     kClassFileLoadHookNonRetransformable = JVMTI_EVENT_CLASS_FILE_LOAD_HOOK,
53     kClassLoad = JVMTI_EVENT_CLASS_LOAD,
54     kClassPrepare = JVMTI_EVENT_CLASS_PREPARE,
55     kVmStart = JVMTI_EVENT_VM_START,
56     kException = JVMTI_EVENT_EXCEPTION,
57     kExceptionCatch = JVMTI_EVENT_EXCEPTION_CATCH,
58     kSingleStep = JVMTI_EVENT_SINGLE_STEP,
59     kFramePop = JVMTI_EVENT_FRAME_POP,
60     kBreakpoint = JVMTI_EVENT_BREAKPOINT,
61     kFieldAccess = JVMTI_EVENT_FIELD_ACCESS,
62     kFieldModification = JVMTI_EVENT_FIELD_MODIFICATION,
63     kMethodEntry = JVMTI_EVENT_METHOD_ENTRY,
64     kMethodExit = JVMTI_EVENT_METHOD_EXIT,
65     kNativeMethodBind = JVMTI_EVENT_NATIVE_METHOD_BIND,
66     kCompiledMethodLoad = JVMTI_EVENT_COMPILED_METHOD_LOAD,
67     kCompiledMethodUnload = JVMTI_EVENT_COMPILED_METHOD_UNLOAD,
68     kDynamicCodeGenerated = JVMTI_EVENT_DYNAMIC_CODE_GENERATED,
69     kDataDumpRequest = JVMTI_EVENT_DATA_DUMP_REQUEST,
70     kMonitorWait = JVMTI_EVENT_MONITOR_WAIT,
71     kMonitorWaited = JVMTI_EVENT_MONITOR_WAITED,
72     kMonitorContendedEnter = JVMTI_EVENT_MONITOR_CONTENDED_ENTER,
73     kMonitorContendedEntered = JVMTI_EVENT_MONITOR_CONTENDED_ENTERED,
74     kResourceExhausted = JVMTI_EVENT_RESOURCE_EXHAUSTED,
75     kGarbageCollectionStart = JVMTI_EVENT_GARBAGE_COLLECTION_START,
76     kGarbageCollectionFinish = JVMTI_EVENT_GARBAGE_COLLECTION_FINISH,
77     kObjectFree = JVMTI_EVENT_OBJECT_FREE,
78     kVmObjectAlloc = JVMTI_EVENT_VM_OBJECT_ALLOC,
79     // Internal event to mark a ClassFileLoadHook as one created with the can_retransform_classes
80     // capability.
81     kClassFileLoadHookRetransformable = JVMTI_MAX_EVENT_TYPE_VAL + 1,
82     kDdmPublishChunk = JVMTI_MAX_EVENT_TYPE_VAL + 2,
83     kObsoleteObjectCreated = JVMTI_MAX_EVENT_TYPE_VAL + 3,
84     kStructuralDexFileLoadHook = JVMTI_MAX_EVENT_TYPE_VAL + 4,
85     kMaxNormalEventTypeVal = kStructuralDexFileLoadHook,
86 
87     // All that follow are events used to implement internal JVMTI functions. They are not settable
88     // directly by agents.
89     kMinInternalEventTypeVal = kMaxNormalEventTypeVal + 1,
90 
91     // Internal event we use to implement the ForceEarlyReturn functions.
92     kForceEarlyReturnUpdateReturnValue = kMinInternalEventTypeVal,
93     kMaxInternalEventTypeVal = kForceEarlyReturnUpdateReturnValue,
94 
95     kMaxEventTypeVal = kMaxInternalEventTypeVal,
96 };
97 
98 constexpr jint kInternalEventCount = static_cast<jint>(ArtJvmtiEvent::kMaxInternalEventTypeVal) -
99                                      static_cast<jint>(ArtJvmtiEvent::kMinInternalEventTypeVal) + 1;
100 
101 using ArtJvmtiEventDdmPublishChunk = void (*)(jvmtiEnv *jvmti_env,
102                                               jint data_type,
103                                               jint data_len,
104                                               const jbyte* data);
105 
106 using ArtJvmtiEventObsoleteObjectCreated = void (*)(jvmtiEnv *jvmti_env,
107                                                     jlong* obsolete_tag,
108                                                     jlong* new_tag);
109 
110 using ArtJvmtiEventStructuralDexFileLoadHook = void (*)(jvmtiEnv *jvmti_env,
111                                                         JNIEnv* jni_env,
112                                                         jclass class_being_redefined,
113                                                         jobject loader,
114                                                         const char* name,
115                                                         jobject protection_domain,
116                                                         jint dex_data_len,
117                                                         const unsigned char* dex_data,
118                                                         jint* new_dex_data_len,
119                                                         unsigned char** new_dex_data);
120 
121 // It is not enough to store a Thread pointer, as these may be reused. Use the pointer and the
122 // thread id.
123 // Note: We could just use the tid like tracing does.
124 using UniqueThread = std::pair<art::Thread*, uint32_t>;
125 
126 struct UniqueThreadHasher {
operatorUniqueThreadHasher127   std::size_t operator()(const UniqueThread& k) const {
128     return std::hash<uint32_t>{}(k.second) ^ (std::hash<void*>{}(k.first) << 1);
129   }
130 };
131 
132 struct ArtJvmtiEventCallbacks : jvmtiEventCallbacks {
ArtJvmtiEventCallbacksArtJvmtiEventCallbacks133   ArtJvmtiEventCallbacks()
134       : DdmPublishChunk(nullptr),
135         ObsoleteObjectCreated(nullptr),
136         StructuralDexFileLoadHook(nullptr) {
137     memset(this, 0, sizeof(jvmtiEventCallbacks));
138   }
139 
140   // Copies extension functions from other callback struct if it exists. There must not have been
141   // any modifications to this struct when it is called.
142   void CopyExtensionsFrom(const ArtJvmtiEventCallbacks* cb);
143 
144   jvmtiError Set(jint index, jvmtiExtensionEvent cb);
145 
146   ArtJvmtiEventDdmPublishChunk DdmPublishChunk;
147   ArtJvmtiEventObsoleteObjectCreated ObsoleteObjectCreated;
148   ArtJvmtiEventStructuralDexFileLoadHook StructuralDexFileLoadHook;
149 };
150 
151 bool IsExtensionEvent(jint e);
152 bool IsExtensionEvent(ArtJvmtiEvent e);
153 
154 // Convert a jvmtiEvent into a ArtJvmtiEvent
155 ALWAYS_INLINE static inline ArtJvmtiEvent GetArtJvmtiEvent(ArtJvmTiEnv* env, jvmtiEvent e);
156 
GetJvmtiEvent(ArtJvmtiEvent e)157 static inline jvmtiEvent GetJvmtiEvent(ArtJvmtiEvent e) {
158   if (UNLIKELY(e == ArtJvmtiEvent::kClassFileLoadHookRetransformable)) {
159     return JVMTI_EVENT_CLASS_FILE_LOAD_HOOK;
160   } else {
161     return static_cast<jvmtiEvent>(e);
162   }
163 }
164 
165 struct EventMask {
166   static constexpr size_t kEventsSize =
167       static_cast<size_t>(ArtJvmtiEvent::kMaxEventTypeVal) -
168       static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal) + 1;
169   std::bitset<kEventsSize> bit_set;
170 
EventIsInRangeEventMask171   static bool EventIsInRange(ArtJvmtiEvent event) {
172     return event >= ArtJvmtiEvent::kMinEventTypeVal && event <= ArtJvmtiEvent::kMaxEventTypeVal;
173   }
174 
175   void Set(ArtJvmtiEvent event, bool value = true) {
176     DCHECK(EventIsInRange(event));
177     bit_set.set(static_cast<size_t>(event) - static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal),
178                 value);
179   }
180 
TestEventMask181   bool Test(ArtJvmtiEvent event) const {
182     DCHECK(EventIsInRange(event));
183     return bit_set.test(
184         static_cast<size_t>(event) - static_cast<size_t>(ArtJvmtiEvent::kMinEventTypeVal));
185   }
186 };
187 
188 struct EventMasks {
189   // The globally enabled events.
190   EventMask global_event_mask;
191 
192   // The per-thread enabled events.
193 
194   // TODO: Native thread objects are immovable, so we can use them as keys in an (unordered) map,
195   //       if necessary.
196   std::vector<std::pair<UniqueThread, EventMask>> thread_event_masks;
197 
198   // A union of the per-thread events, for fast-pathing.
199   EventMask unioned_thread_event_mask;
200 
201   EventMask& GetEventMask(art::Thread* thread);
202   EventMask* GetEventMaskOrNull(art::Thread* thread);
203   // Circular dependencies mean we cannot see the definition of ArtJvmTiEnv so the mutex is simply
204   // asserted in the function.
205   // Note that the 'env' passed in must be the same env this EventMasks is associated with.
206   void EnableEvent(ArtJvmTiEnv* env, art::Thread* thread, ArtJvmtiEvent event);
207       // REQUIRES(env->event_info_mutex_);
208   // Circular dependencies mean we cannot see the definition of ArtJvmTiEnv so the mutex is simply
209   // asserted in the function.
210   // Note that the 'env' passed in must be the same env this EventMasks is associated with.
211   void DisableEvent(ArtJvmTiEnv* env, art::Thread* thread, ArtJvmtiEvent event);
212       // REQUIRES(env->event_info_mutex_);
213   bool IsEnabledAnywhere(ArtJvmtiEvent event);
214   // Make any changes to event masks needed for the given capability changes. If caps_added is true
215   // then caps is all the newly set capabilities of the jvmtiEnv. If it is false then caps is the
216   // set of all capabilities that were removed from the jvmtiEnv.
217   void HandleChangedCapabilities(const jvmtiCapabilities& caps, bool caps_added);
218 };
219 
220 namespace impl {
221 template <ArtJvmtiEvent kEvent> struct EventHandlerFunc { };
222 }  // namespace impl
223 
224 // Helper class for event handling.
225 class EventHandler {
226  public:
227   EventHandler();
228   ~EventHandler();
229 
230   // do cleanup for the event handler.
231   void Shutdown();
232 
233   // Register an env. It is assumed that this happens on env creation, that is, no events are
234   // enabled, yet.
235   void RegisterArtJvmTiEnv(ArtJvmTiEnv* env) REQUIRES(!envs_lock_);
236 
237   // Remove an env.
238   void RemoveArtJvmTiEnv(ArtJvmTiEnv* env) REQUIRES(!envs_lock_);
239 
IsEventEnabledAnywhere(ArtJvmtiEvent event)240   bool IsEventEnabledAnywhere(ArtJvmtiEvent event) const {
241     if (!EventMask::EventIsInRange(event)) {
242       return false;
243     }
244     return global_mask.Test(event);
245   }
246 
247   // Sets an internal event. Unlike normal JVMTI events internal events are not associated with any
248   // particular jvmtiEnv and are refcounted. This refcounting is done to allow us to easily enable
249   // events during functions and disable them during the requested event callback. Since these are
250   // used to implement various JVMTI functions these events always have a single target thread. If
251   // target is null the current thread is used.
252   jvmtiError SetInternalEvent(jthread target,
253                               ArtJvmtiEvent event,
254                               jvmtiEventMode mode)
255       REQUIRES(!envs_lock_, !art::Locks::mutator_lock_);
256 
257   jvmtiError SetEvent(ArtJvmTiEnv* env,
258                       jthread thread,
259                       ArtJvmtiEvent event,
260                       jvmtiEventMode mode)
261       REQUIRES(!envs_lock_);
262 
263   // Dispatch event to all registered environments. Since this one doesn't have a JNIEnv* it doesn't
264   // matter if it has the mutator_lock.
265   template <ArtJvmtiEvent kEvent, typename ...Args>
266   ALWAYS_INLINE
267   inline void DispatchEvent(art::Thread* thread, Args... args) const
268       REQUIRES(!envs_lock_);
269 
270   // Dispatch event to all registered environments stashing exceptions as needed. This works since
271   // JNIEnv* is always the second argument if it is passed to an event. Needed since C++ does not
272   // allow partial template function specialization.
273   //
274   // We need both of these since we want to make sure to push a stack frame when it is possible for
275   // the event to allocate local references.
276   template <ArtJvmtiEvent kEvent, typename ...Args>
277   ALWAYS_INLINE
278   inline void DispatchEvent(art::Thread* thread, JNIEnv* jnienv, Args... args) const
279       REQUIRES(!envs_lock_);
280 
281   // Tell the event handler capabilities were added/lost so it can adjust the sent events.If
282   // caps_added is true then caps is all the newly set capabilities of the jvmtiEnv. If it is false
283   // then caps is the set of all capabilities that were removed from the jvmtiEnv.
284   ALWAYS_INLINE
285   inline void HandleChangedCapabilities(ArtJvmTiEnv* env,
286                                         const jvmtiCapabilities& caps,
287                                         bool added)
288       REQUIRES(!envs_lock_);
289 
290   // Dispatch event to the given environment, only.
291   template <ArtJvmtiEvent kEvent, typename ...Args>
292   ALWAYS_INLINE
293   inline void DispatchEventOnEnv(ArtJvmTiEnv* env,
294                                  art::Thread* thread,
295                                  JNIEnv* jnienv,
296                                  Args... args) const
297       REQUIRES(!envs_lock_);
298 
299   // Dispatch event to the given environment, only.
300   template <ArtJvmtiEvent kEvent, typename ...Args>
301   ALWAYS_INLINE
302   inline void DispatchEventOnEnv(ArtJvmTiEnv* env, art::Thread* thread, Args... args) const
303       REQUIRES(!envs_lock_);
304 
305   void AddDelayedNonStandardExitEvent(const art::ShadowFrame* frame, bool is_object, jvalue val)
306       REQUIRES_SHARED(art::Locks::mutator_lock_)
307       REQUIRES(art::Locks::user_code_suspension_lock_, art::Locks::thread_list_lock_);
308 
309   template<typename Visitor>
ForEachEnv(art::Thread * self,Visitor v)310   void ForEachEnv(art::Thread* self, Visitor v) REQUIRES(!envs_lock_) {
311     art::ReaderMutexLock mu(self, envs_lock_);
312     for (ArtJvmTiEnv* e : envs) {
313       if (e != nullptr) {
314         v(e);
315       }
316     }
317   }
318 
319  private:
320   void SetupTraceListener(JvmtiMethodTraceListener* listener, ArtJvmtiEvent event, bool enable);
321 
322   uint32_t GetInstrumentationEventsFor(ArtJvmtiEvent event);
323 
324   // Specifically handle the FramePop event which it might not always be possible to turn off.
325   void SetupFramePopTraceListener(bool enable);
326 
327   template <ArtJvmtiEvent kEvent, typename ...Args>
328   ALWAYS_INLINE
329   inline std::vector<impl::EventHandlerFunc<kEvent>> CollectEvents(art::Thread* thread,
330                                                                    Args... args) const
331       REQUIRES(!envs_lock_);
332 
333   template <ArtJvmtiEvent kEvent>
334   ALWAYS_INLINE
335   inline bool ShouldDispatchOnThread(ArtJvmTiEnv* env, art::Thread* thread) const;
336 
337   template <ArtJvmtiEvent kEvent, typename ...Args>
338   ALWAYS_INLINE
339   static inline void ExecuteCallback(impl::EventHandlerFunc<kEvent> handler,
340                                      JNIEnv* env,
341                                      Args... args)
342       REQUIRES(!envs_lock_);
343 
344   template <ArtJvmtiEvent kEvent, typename ...Args>
345   ALWAYS_INLINE
346   static inline void ExecuteCallback(impl::EventHandlerFunc<kEvent> handler, Args... args)
347       REQUIRES(!envs_lock_);
348 
349   // Public for use to collect dispatches
350   template <ArtJvmtiEvent kEvent, typename ...Args>
351   ALWAYS_INLINE
352   inline bool ShouldDispatch(ArtJvmTiEnv* env, art::Thread* thread, Args... args) const;
353 
354   ALWAYS_INLINE
355   inline bool NeedsEventUpdate(ArtJvmTiEnv* env,
356                                const jvmtiCapabilities& caps,
357                                bool added);
358 
359   // Recalculates the event mask for the given event.
360   ALWAYS_INLINE
361   inline void RecalculateGlobalEventMask(ArtJvmtiEvent event) REQUIRES(!envs_lock_);
362   ALWAYS_INLINE
363   inline void RecalculateGlobalEventMaskLocked(ArtJvmtiEvent event) REQUIRES_SHARED(envs_lock_);
364 
365   // Returns whether there are any active requests for the given event on the given thread. This
366   // should only be used while modifying the events for a thread.
367   bool GetThreadEventState(ArtJvmtiEvent event, art::Thread* thread)
368       REQUIRES(envs_lock_, art::Locks::thread_list_lock_);
369 
370   template <ArtJvmtiEvent kEvent>
371   ALWAYS_INLINE inline void DispatchClassFileLoadHookEvent(art::Thread* thread,
372                                                            JNIEnv* jnienv,
373                                                            jclass class_being_redefined,
374                                                            jobject loader,
375                                                            const char* name,
376                                                            jobject protection_domain,
377                                                            jint class_data_len,
378                                                            const unsigned char* class_data,
379                                                            jint* new_class_data_len,
380                                                            unsigned char** new_class_data) const
381       REQUIRES(!envs_lock_);
382 
383   template <ArtJvmtiEvent kEvent>
384   ALWAYS_INLINE inline void DispatchClassLoadOrPrepareEvent(art::Thread* thread,
385                                                             JNIEnv* jnienv,
386                                                             jthread jni_thread,
387                                                             jclass klass) const
388       REQUIRES(!envs_lock_);
389 
390   // Sets up the global state needed for the first/last enable of an event across all threads
391   void HandleEventType(ArtJvmtiEvent event, bool enable);
392   // Perform deopts required for enabling the event on the given thread. Null thread indicates
393   // global event enabled.
394   jvmtiError HandleEventDeopt(ArtJvmtiEvent event, jthread thread, bool enable);
395   void HandleLocalAccessCapabilityAdded();
396   void HandleBreakpointEventsChanged(bool enable);
397 
398   bool OtherMonitorEventsEnabledAnywhere(ArtJvmtiEvent event);
399 
400   int32_t GetInternalEventRefcount(ArtJvmtiEvent event) const REQUIRES(envs_lock_);
401   // Increment internal event refcount for the given event and return the new count.
402   int32_t IncrInternalEventRefcount(ArtJvmtiEvent event) REQUIRES(envs_lock_);
403   // Decrement internal event refcount for the given event and return the new count.
404   int32_t DecrInternalEventRefcount(ArtJvmtiEvent event) REQUIRES(envs_lock_);
405 
406   int32_t& GetInternalEventThreadRefcount(ArtJvmtiEvent event, art::Thread* target)
407       REQUIRES(envs_lock_, art::Locks::thread_list_lock_);
408   // Increment internal event refcount for the given event and return the new count.
409   int32_t IncrInternalEventThreadRefcount(ArtJvmtiEvent event, art::Thread* target)
410       REQUIRES(envs_lock_, art::Locks::thread_list_lock_);
411   // Decrement internal event refcount for the given event and return the new count.
412   int32_t DecrInternalEventThreadRefcount(ArtJvmtiEvent event, art::Thread* target)
413       REQUIRES(envs_lock_, art::Locks::thread_list_lock_);
414 
415   // List of all JvmTiEnv objects that have been created, in their creation order. It is a std::list
416   // since we mostly access it by iterating over the entire thing, only ever append to the end, and
417   // need to be able to remove arbitrary elements from it.
418   std::list<ArtJvmTiEnv*> envs GUARDED_BY(envs_lock_);
419 
420   // Close to top level lock. Nothing should be held when we lock this (except for mutator_lock_
421   // which is needed when setting new events).
422   mutable art::ReaderWriterMutex envs_lock_ ACQUIRED_AFTER(art::Locks::mutator_lock_);
423 
424   // A union of all enabled events, anywhere.
425   EventMask global_mask;
426 
427   std::unique_ptr<JvmtiEventAllocationListener> alloc_listener_;
428   std::unique_ptr<JvmtiDdmChunkListener> ddm_listener_;
429   std::unique_ptr<JvmtiGcPauseListener> gc_pause_listener_;
430   std::unique_ptr<JvmtiMethodTraceListener> method_trace_listener_;
431   std::unique_ptr<JvmtiMonitorListener> monitor_listener_;
432   std::unique_ptr<JvmtiParkListener> park_listener_;
433 
434   // True if frame pop has ever been enabled. Since we store pointers to stack frames we need to
435   // continue to listen to this event even if it has been disabled.
436   // TODO We could remove the listeners once all jvmtiEnvs have drained their shadow-frame vectors.
437   bool frame_pop_enabled;
438 
439   // The overall refcount for each internal event across all threads.
440   std::array<int32_t, kInternalEventCount> internal_event_refcount_ GUARDED_BY(envs_lock_);
441   // The refcount for each thread for each internal event.
442   // TODO We should clean both this and the normal EventMask lists up when threads end.
443   std::array<std::unordered_map<UniqueThread, int32_t, UniqueThreadHasher>, kInternalEventCount>
444       internal_event_thread_refcount_
445           GUARDED_BY(envs_lock_) GUARDED_BY(art::Locks::thread_list_lock_);
446 
447   friend class JvmtiMethodTraceListener;
448 };
449 
450 }  // namespace openjdkjvmti
451 
452 #endif  // ART_OPENJDKJVMTI_EVENTS_H_
453