1 /* Copyright (C) 2016 The Android Open Source Project
2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3  *
4  * This file implements interfaces from the file jvmti.h. This implementation
5  * is licensed under the same terms as the file jvmti.h.  The
6  * copyright and license information for the file jvmti.h follows.
7  *
8  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
9  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
10  *
11  * This code is free software; you can redistribute it and/or modify it
12  * under the terms of the GNU General Public License version 2 only, as
13  * published by the Free Software Foundation.  Oracle designates this
14  * particular file as subject to the "Classpath" exception as provided
15  * by Oracle in the LICENSE file that accompanied this code.
16  *
17  * This code is distributed in the hope that it will be useful, but WITHOUT
18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
20  * version 2 for more details (a copy is included in the LICENSE file that
21  * accompanied this code).
22  *
23  * You should have received a copy of the GNU General Public License version
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31 
32 #include <error.h>
33 #include <stddef.h>
34 #include <sys/types.h>
35 
36 #include <unordered_map>
37 #include <unordered_set>
38 
39 #include "transform.h"
40 
41 #include "art_method.h"
42 #include "base/array_ref.h"
43 #include "base/globals.h"
44 #include "base/logging.h"
45 #include "base/mem_map.h"
46 #include "class_linker.h"
47 #include "dex/dex_file.h"
48 #include "dex/dex_file_types.h"
49 #include "dex/utf.h"
50 #include "events-inl.h"
51 #include "events.h"
52 #include "fault_handler.h"
53 #include "gc_root-inl.h"
54 #include "handle_scope-inl.h"
55 #include "jni/jni_env_ext-inl.h"
56 #include "jvalue.h"
57 #include "jvmti.h"
58 #include "linear_alloc.h"
59 #include "mirror/array.h"
60 #include "mirror/class-inl.h"
61 #include "mirror/class_ext.h"
62 #include "mirror/class_loader-inl.h"
63 #include "mirror/string-inl.h"
64 #include "oat_file.h"
65 #include "scoped_thread_state_change-inl.h"
66 #include "stack.h"
67 #include "thread_list.h"
68 #include "ti_redefine.h"
69 #include "ti_logging.h"
70 #include "transform.h"
71 #include "utils/dex_cache_arrays_layout-inl.h"
72 
73 namespace openjdkjvmti {
74 
75 // A FaultHandler that will deal with initializing ClassDefinitions when they are actually needed.
76 class TransformationFaultHandler final : public art::FaultHandler {
77  public:
TransformationFaultHandler(art::FaultManager * manager)78   explicit TransformationFaultHandler(art::FaultManager* manager)
79       : art::FaultHandler(manager),
80         uninitialized_class_definitions_lock_("JVMTI Initialized class definitions lock",
81                                               art::LockLevel::kSignalHandlingLock),
82         class_definition_initialized_cond_("JVMTI Initialized class definitions condition",
83                                            uninitialized_class_definitions_lock_) {
84     manager->AddHandler(this, /* generated_code= */ false);
85   }
86 
~TransformationFaultHandler()87   ~TransformationFaultHandler() {
88     art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
89     uninitialized_class_definitions_.clear();
90   }
91 
Action(int sig,siginfo_t * siginfo,void * context ATTRIBUTE_UNUSED)92   bool Action(int sig, siginfo_t* siginfo, void* context ATTRIBUTE_UNUSED) override {
93     DCHECK_EQ(sig, SIGSEGV);
94     art::Thread* self = art::Thread::Current();
95     uintptr_t ptr = reinterpret_cast<uintptr_t>(siginfo->si_addr);
96     if (UNLIKELY(uninitialized_class_definitions_lock_.IsExclusiveHeld(self))) {
97       // It's possible this is just some other unrelated segv that should be
98       // handled separately, continue to later handlers. This is likely due to
99       // running out of memory somewhere along the FixedUpDexFile pipeline and
100       // is likely unrecoverable. By returning false here though we will get a
101       // better, more accurate, stack-trace later that points to the actual
102       // issue.
103       LOG(WARNING) << "Recursive SEGV occurred during Transformation dequickening at 0x" << std::hex
104                    << ptr;
105       return false;
106     }
107     ArtClassDefinition* res = nullptr;
108 
109     {
110       // NB Technically using a mutex and condition variables here is non-posix compliant but
111       // everything should be fine since both glibc and bionic implementations of mutexs and
112       // condition variables work fine so long as the thread was not interrupted during a
113       // lock/unlock (which it wasn't) on all architectures we care about.
114       art::MutexLock mu(self, uninitialized_class_definitions_lock_);
115       auto it = std::find_if(uninitialized_class_definitions_.begin(),
116                              uninitialized_class_definitions_.end(),
117                              [&](const auto op) { return op->ContainsAddress(ptr); });
118       if (it != uninitialized_class_definitions_.end()) {
119         res = *it;
120         // Remove the class definition.
121         uninitialized_class_definitions_.erase(it);
122         // Put it in the initializing list
123         initializing_class_definitions_.push_back(res);
124       } else {
125         // Wait for the ptr to be initialized (if it is currently initializing).
126         while (DefinitionIsInitializing(ptr)) {
127           WaitForClassInitializationToFinish();
128         }
129         // Return true (continue with user code) if we find that the definition has been
130         // initialized. Return false (continue on to next signal handler) if the definition is not
131         // initialized or found.
132         return std::find_if(initialized_class_definitions_.begin(),
133                             initialized_class_definitions_.end(),
134                             [&](const auto op) { return op->ContainsAddress(ptr); }) !=
135             initialized_class_definitions_.end();
136       }
137     }
138 
139     if (LIKELY(self != nullptr)) {
140       CHECK_EQ(self->GetState(), art::ThreadState::kNative)
141           << "Transformation fault handler occurred outside of native mode";
142     }
143 
144     VLOG(signals) << "Lazy initialization of dex file for transformation of " << res->GetName()
145                   << " during SEGV";
146     res->InitializeMemory();
147 
148     {
149       art::MutexLock mu(self, uninitialized_class_definitions_lock_);
150       // Move to initialized state and notify waiters.
151       initializing_class_definitions_.erase(std::find(initializing_class_definitions_.begin(),
152                                                       initializing_class_definitions_.end(),
153                                                       res));
154       initialized_class_definitions_.push_back(res);
155       class_definition_initialized_cond_.Broadcast(self);
156     }
157 
158     return true;
159   }
160 
RemoveDefinition(ArtClassDefinition * def)161   void RemoveDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
162     art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
163     auto it = std::find(uninitialized_class_definitions_.begin(),
164                         uninitialized_class_definitions_.end(),
165                         def);
166     if (it != uninitialized_class_definitions_.end()) {
167       uninitialized_class_definitions_.erase(it);
168       return;
169     }
170     while (std::find(initializing_class_definitions_.begin(),
171                      initializing_class_definitions_.end(),
172                      def) != initializing_class_definitions_.end()) {
173       WaitForClassInitializationToFinish();
174     }
175     it = std::find(initialized_class_definitions_.begin(),
176                    initialized_class_definitions_.end(),
177                    def);
178     CHECK(it != initialized_class_definitions_.end()) << "Could not find class definition for "
179                                                       << def->GetName();
180     initialized_class_definitions_.erase(it);
181   }
182 
AddArtDefinition(ArtClassDefinition * def)183   void AddArtDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
184     DCHECK(def->IsLazyDefinition());
185     art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
186     uninitialized_class_definitions_.push_back(def);
187   }
188 
189  private:
DefinitionIsInitializing(uintptr_t ptr)190   bool DefinitionIsInitializing(uintptr_t ptr) REQUIRES(uninitialized_class_definitions_lock_) {
191     return std::find_if(initializing_class_definitions_.begin(),
192                         initializing_class_definitions_.end(),
193                         [&](const auto op) { return op->ContainsAddress(ptr); }) !=
194         initializing_class_definitions_.end();
195   }
196 
WaitForClassInitializationToFinish()197   void WaitForClassInitializationToFinish() REQUIRES(uninitialized_class_definitions_lock_) {
198     class_definition_initialized_cond_.Wait(art::Thread::Current());
199   }
200 
201   art::Mutex uninitialized_class_definitions_lock_ ACQUIRED_BEFORE(art::Locks::abort_lock_);
202   art::ConditionVariable class_definition_initialized_cond_
203       GUARDED_BY(uninitialized_class_definitions_lock_);
204 
205   // A list of the class definitions that have a non-readable map.
206   std::vector<ArtClassDefinition*> uninitialized_class_definitions_
207       GUARDED_BY(uninitialized_class_definitions_lock_);
208 
209   // A list of class definitions that are currently undergoing unquickening. Threads should wait
210   // until the definition is no longer in this before returning.
211   std::vector<ArtClassDefinition*> initializing_class_definitions_
212       GUARDED_BY(uninitialized_class_definitions_lock_);
213 
214   // A list of class definitions that are already unquickened. Threads should immediately return if
215   // it is here.
216   std::vector<ArtClassDefinition*> initialized_class_definitions_
217       GUARDED_BY(uninitialized_class_definitions_lock_);
218 };
219 
220 static TransformationFaultHandler* gTransformFaultHandler = nullptr;
221 static EventHandler* gEventHandler = nullptr;
222 
223 
Register(EventHandler * eh)224 void Transformer::Register(EventHandler* eh) {
225   // Although we create this the fault handler is actually owned by the 'art::fault_manager' which
226   // will take care of destroying it.
227   if (art::MemMap::kCanReplaceMapping && ArtClassDefinition::kEnableOnDemandDexDequicken) {
228     gTransformFaultHandler = new TransformationFaultHandler(&art::fault_manager);
229   }
230   gEventHandler = eh;
231 }
232 
233 // Simple helper to add and remove the class definition from the fault handler.
234 class ScopedDefinitionHandler {
235  public:
ScopedDefinitionHandler(ArtClassDefinition * def)236   explicit ScopedDefinitionHandler(ArtClassDefinition* def)
237       : def_(def), is_lazy_(def_->IsLazyDefinition()) {
238     if (is_lazy_) {
239       gTransformFaultHandler->AddArtDefinition(def_);
240     }
241   }
242 
~ScopedDefinitionHandler()243   ~ScopedDefinitionHandler() {
244     if (is_lazy_) {
245       gTransformFaultHandler->RemoveDefinition(def_);
246     }
247   }
248 
249  private:
250   ArtClassDefinition* def_;
251   bool is_lazy_;
252 };
253 
254 // Initialize templates.
255 template
256 void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookNonRetransformable>(
257     EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
258 template
259 void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookRetransformable>(
260     EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
261 template
262 void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kStructuralDexFileLoadHook>(
263     EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
264 
265 template<ArtJvmtiEvent kEvent>
TransformSingleClassDirect(EventHandler * event_handler,art::Thread * self,ArtClassDefinition * def)266 void Transformer::TransformSingleClassDirect(EventHandler* event_handler,
267                                              art::Thread* self,
268                                              /*in-out*/ArtClassDefinition* def) {
269   static_assert(kEvent == ArtJvmtiEvent::kClassFileLoadHookNonRetransformable ||
270                 kEvent == ArtJvmtiEvent::kClassFileLoadHookRetransformable ||
271                 kEvent == ArtJvmtiEvent::kStructuralDexFileLoadHook,
272                 "bad event type");
273   // We don't want to do transitions between calling the event and setting the new data so change to
274   // native state early. This also avoids any problems that the FaultHandler might have in
275   // determining if an access to the dex_data is from generated code or not.
276   art::ScopedThreadStateChange stsc(self, art::ThreadState::kNative);
277   ScopedDefinitionHandler handler(def);
278   jint new_len = -1;
279   unsigned char* new_data = nullptr;
280   art::ArrayRef<const unsigned char> dex_data = def->GetDexData();
281   event_handler->DispatchEvent<kEvent>(
282       self,
283       static_cast<JNIEnv*>(self->GetJniEnv()),
284       def->GetClass(),
285       def->GetLoader(),
286       def->GetName().c_str(),
287       def->GetProtectionDomain(),
288       static_cast<jint>(dex_data.size()),
289       dex_data.data(),
290       /*out*/&new_len,
291       /*out*/&new_data);
292   def->SetNewDexData(new_len, new_data, kEvent);
293 }
294 
295 template <RedefinitionType kType>
RetransformClassesDirect(art::Thread * self,std::vector<ArtClassDefinition> * definitions)296 void Transformer::RetransformClassesDirect(
297     art::Thread* self,
298     /*in-out*/ std::vector<ArtClassDefinition>* definitions) {
299   constexpr ArtJvmtiEvent kEvent = kType == RedefinitionType::kNormal
300                                        ? ArtJvmtiEvent::kClassFileLoadHookRetransformable
301                                        : ArtJvmtiEvent::kStructuralDexFileLoadHook;
302   for (ArtClassDefinition& def : *definitions) {
303     TransformSingleClassDirect<kEvent>(gEventHandler, self, &def);
304   }
305 }
306 
307 template void Transformer::RetransformClassesDirect<RedefinitionType::kNormal>(
308       art::Thread* self, /*in-out*/std::vector<ArtClassDefinition>* definitions);
309 template void Transformer::RetransformClassesDirect<RedefinitionType::kStructural>(
310       art::Thread* self, /*in-out*/std::vector<ArtClassDefinition>* definitions);
311 
RetransformClasses(jvmtiEnv * env,jint class_count,const jclass * classes)312 jvmtiError Transformer::RetransformClasses(jvmtiEnv* env,
313                                            jint class_count,
314                                            const jclass* classes) {
315   if (class_count < 0) {
316     JVMTI_LOG(WARNING, env) << "FAILURE TO RETRANSFORM class_count was less then 0";
317     return ERR(ILLEGAL_ARGUMENT);
318   } else if (class_count == 0) {
319     // We don't actually need to do anything. Just return OK.
320     return OK;
321   } else if (classes == nullptr) {
322     JVMTI_LOG(WARNING, env) << "FAILURE TO RETRANSFORM null classes!";
323     return ERR(NULL_POINTER);
324   }
325   art::Thread* self = art::Thread::Current();
326   art::Runtime* runtime = art::Runtime::Current();
327   // A holder that will Deallocate all the class bytes buffers on destruction.
328   std::string error_msg;
329   std::vector<ArtClassDefinition> definitions;
330   jvmtiError res = OK;
331   for (jint i = 0; i < class_count; i++) {
332     res = Redefiner::GetClassRedefinitionError<RedefinitionType::kNormal>(classes[i], &error_msg);
333     if (res != OK) {
334       JVMTI_LOG(WARNING, env) << "FAILURE TO RETRANSFORM " << error_msg;
335       return res;
336     }
337     ArtClassDefinition def;
338     res = def.Init(self, classes[i]);
339     if (res != OK) {
340       JVMTI_LOG(WARNING, env) << "FAILURE TO RETRANSFORM definition init failed";
341       return res;
342     }
343     definitions.push_back(std::move(def));
344   }
345   RetransformClassesDirect<RedefinitionType::kStructural>(self, &definitions);
346   RetransformClassesDirect<RedefinitionType::kNormal>(self, &definitions);
347   RedefinitionType redef_type =
348       std::any_of(definitions.cbegin(),
349                   definitions.cend(),
350                   [](const auto& it) { return it.HasStructuralChanges(); })
351           ? RedefinitionType::kStructural
352           : RedefinitionType::kNormal;
353   res = Redefiner::RedefineClassesDirect(
354       ArtJvmTiEnv::AsArtJvmTiEnv(env), runtime, self, definitions, redef_type, &error_msg);
355   if (res != OK) {
356     JVMTI_LOG(WARNING, env) << "FAILURE TO RETRANSFORM " << error_msg;
357   }
358   return res;
359 }
360 
361 // TODO Move this somewhere else, ti_class?
GetClassLocation(ArtJvmTiEnv * env,jclass klass,std::string * location)362 jvmtiError GetClassLocation(ArtJvmTiEnv* env, jclass klass, /*out*/std::string* location) {
363   JNIEnv* jni_env = nullptr;
364   jint ret = env->art_vm->GetEnv(reinterpret_cast<void**>(&jni_env), JNI_VERSION_1_1);
365   if (ret != JNI_OK) {
366     // TODO Different error might be better?
367     return ERR(INTERNAL);
368   }
369   art::ScopedObjectAccess soa(jni_env);
370   art::StackHandleScope<1> hs(art::Thread::Current());
371   art::Handle<art::mirror::Class> hs_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
372   const art::DexFile& dex = hs_klass->GetDexFile();
373   *location = dex.GetLocation();
374   return OK;
375 }
376 
377 }  // namespace openjdkjvmti
378