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
24 * 2 along with this work; if not, write to the Free Software Foundation,
25 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
26 *
27 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
28 * or visit www.oracle.com if you need additional information or have any
29 * questions.
30 */
31
32 #include <stddef.h>
33 #include <sys/types.h>
34
35 #include <unordered_map>
36 #include <unordered_set>
37
38 #include "transform.h"
39
40 #include "art_method.h"
41 #include "base/array_ref.h"
42 #include "base/globals.h"
43 #include "base/logging.h"
44 #include "base/mem_map.h"
45 #include "class_linker.h"
46 #include "dex/dex_file.h"
47 #include "dex/dex_file_types.h"
48 #include "dex/utf.h"
49 #include "events-inl.h"
50 #include "fault_handler.h"
51 #include "gc_root-inl.h"
52 #include "handle_scope-inl.h"
53 #include "jni/jni_env_ext-inl.h"
54 #include "jvalue.h"
55 #include "jvmti.h"
56 #include "linear_alloc.h"
57 #include "mirror/array.h"
58 #include "mirror/class-inl.h"
59 #include "mirror/class_ext.h"
60 #include "mirror/class_loader-inl.h"
61 #include "mirror/string-inl.h"
62 #include "oat_file.h"
63 #include "scoped_thread_state_change-inl.h"
64 #include "stack.h"
65 #include "thread_list.h"
66 #include "ti_redefine.h"
67 #include "transform.h"
68 #include "utils/dex_cache_arrays_layout-inl.h"
69
70 namespace openjdkjvmti {
71
72 // A FaultHandler that will deal with initializing ClassDefinitions when they are actually needed.
73 class TransformationFaultHandler final : public art::FaultHandler {
74 public:
TransformationFaultHandler(art::FaultManager * manager)75 explicit TransformationFaultHandler(art::FaultManager* manager)
76 : art::FaultHandler(manager),
77 uninitialized_class_definitions_lock_("JVMTI Initialized class definitions lock",
78 art::LockLevel::kSignalHandlingLock),
79 class_definition_initialized_cond_("JVMTI Initialized class definitions condition",
80 uninitialized_class_definitions_lock_) {
81 manager->AddHandler(this, /* generated_code= */ false);
82 }
83
~TransformationFaultHandler()84 ~TransformationFaultHandler() {
85 art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
86 uninitialized_class_definitions_.clear();
87 }
88
Action(int sig,siginfo_t * siginfo,void * context ATTRIBUTE_UNUSED)89 bool Action(int sig, siginfo_t* siginfo, void* context ATTRIBUTE_UNUSED) override {
90 DCHECK_EQ(sig, SIGSEGV);
91 art::Thread* self = art::Thread::Current();
92 if (UNLIKELY(uninitialized_class_definitions_lock_.IsExclusiveHeld(self))) {
93 if (self != nullptr) {
94 LOG(FATAL) << "Recursive call into Transformation fault handler!";
95 UNREACHABLE();
96 } else {
97 LOG(ERROR) << "Possible deadlock due to recursive signal delivery of segv.";
98 }
99 }
100 uintptr_t ptr = reinterpret_cast<uintptr_t>(siginfo->si_addr);
101 ArtClassDefinition* res = nullptr;
102
103 {
104 // NB Technically using a mutex and condition variables here is non-posix compliant but
105 // everything should be fine since both glibc and bionic implementations of mutexs and
106 // condition variables work fine so long as the thread was not interrupted during a
107 // lock/unlock (which it wasn't) on all architectures we care about.
108 art::MutexLock mu(self, uninitialized_class_definitions_lock_);
109 auto it = std::find_if(uninitialized_class_definitions_.begin(),
110 uninitialized_class_definitions_.end(),
111 [&](const auto op) { return op->ContainsAddress(ptr); });
112 if (it != uninitialized_class_definitions_.end()) {
113 res = *it;
114 // Remove the class definition.
115 uninitialized_class_definitions_.erase(it);
116 // Put it in the initializing list
117 initializing_class_definitions_.push_back(res);
118 } else {
119 // Wait for the ptr to be initialized (if it is currently initializing).
120 while (DefinitionIsInitializing(ptr)) {
121 WaitForClassInitializationToFinish();
122 }
123 // Return true (continue with user code) if we find that the definition has been
124 // initialized. Return false (continue on to next signal handler) if the definition is not
125 // initialized or found.
126 return std::find_if(initialized_class_definitions_.begin(),
127 initialized_class_definitions_.end(),
128 [&](const auto op) { return op->ContainsAddress(ptr); }) !=
129 initialized_class_definitions_.end();
130 }
131 }
132
133 if (LIKELY(self != nullptr)) {
134 CHECK_EQ(self->GetState(), art::ThreadState::kNative)
135 << "Transformation fault handler occurred outside of native mode";
136 }
137
138 VLOG(signals) << "Lazy initialization of dex file for transformation of " << res->GetName()
139 << " during SEGV";
140 res->InitializeMemory();
141
142 {
143 art::MutexLock mu(self, uninitialized_class_definitions_lock_);
144 // Move to initialized state and notify waiters.
145 initializing_class_definitions_.erase(std::find(initializing_class_definitions_.begin(),
146 initializing_class_definitions_.end(),
147 res));
148 initialized_class_definitions_.push_back(res);
149 class_definition_initialized_cond_.Broadcast(self);
150 }
151
152 return true;
153 }
154
RemoveDefinition(ArtClassDefinition * def)155 void RemoveDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
156 art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
157 auto it = std::find(uninitialized_class_definitions_.begin(),
158 uninitialized_class_definitions_.end(),
159 def);
160 if (it != uninitialized_class_definitions_.end()) {
161 uninitialized_class_definitions_.erase(it);
162 return;
163 }
164 while (std::find(initializing_class_definitions_.begin(),
165 initializing_class_definitions_.end(),
166 def) != initializing_class_definitions_.end()) {
167 WaitForClassInitializationToFinish();
168 }
169 it = std::find(initialized_class_definitions_.begin(),
170 initialized_class_definitions_.end(),
171 def);
172 CHECK(it != initialized_class_definitions_.end()) << "Could not find class definition for "
173 << def->GetName();
174 initialized_class_definitions_.erase(it);
175 }
176
AddArtDefinition(ArtClassDefinition * def)177 void AddArtDefinition(ArtClassDefinition* def) REQUIRES(!uninitialized_class_definitions_lock_) {
178 DCHECK(def->IsLazyDefinition());
179 art::MutexLock mu(art::Thread::Current(), uninitialized_class_definitions_lock_);
180 uninitialized_class_definitions_.push_back(def);
181 }
182
183 private:
DefinitionIsInitializing(uintptr_t ptr)184 bool DefinitionIsInitializing(uintptr_t ptr) REQUIRES(uninitialized_class_definitions_lock_) {
185 return std::find_if(initializing_class_definitions_.begin(),
186 initializing_class_definitions_.end(),
187 [&](const auto op) { return op->ContainsAddress(ptr); }) !=
188 initializing_class_definitions_.end();
189 }
190
WaitForClassInitializationToFinish()191 void WaitForClassInitializationToFinish() REQUIRES(uninitialized_class_definitions_lock_) {
192 class_definition_initialized_cond_.Wait(art::Thread::Current());
193 }
194
195 art::Mutex uninitialized_class_definitions_lock_ ACQUIRED_BEFORE(art::Locks::abort_lock_);
196 art::ConditionVariable class_definition_initialized_cond_
197 GUARDED_BY(uninitialized_class_definitions_lock_);
198
199 // A list of the class definitions that have a non-readable map.
200 std::vector<ArtClassDefinition*> uninitialized_class_definitions_
201 GUARDED_BY(uninitialized_class_definitions_lock_);
202
203 // A list of class definitions that are currently undergoing unquickening. Threads should wait
204 // until the definition is no longer in this before returning.
205 std::vector<ArtClassDefinition*> initializing_class_definitions_
206 GUARDED_BY(uninitialized_class_definitions_lock_);
207
208 // A list of class definitions that are already unquickened. Threads should immediately return if
209 // it is here.
210 std::vector<ArtClassDefinition*> initialized_class_definitions_
211 GUARDED_BY(uninitialized_class_definitions_lock_);
212 };
213
214 static TransformationFaultHandler* gTransformFaultHandler = nullptr;
215
Setup()216 void Transformer::Setup() {
217 // Although we create this the fault handler is actually owned by the 'art::fault_manager' which
218 // will take care of destroying it.
219 if (art::MemMap::kCanReplaceMapping && ArtClassDefinition::kEnableOnDemandDexDequicken) {
220 gTransformFaultHandler = new TransformationFaultHandler(&art::fault_manager);
221 }
222 }
223
224 // Simple helper to add and remove the class definition from the fault handler.
225 class ScopedDefinitionHandler {
226 public:
ScopedDefinitionHandler(ArtClassDefinition * def)227 explicit ScopedDefinitionHandler(ArtClassDefinition* def)
228 : def_(def), is_lazy_(def_->IsLazyDefinition()) {
229 if (is_lazy_) {
230 gTransformFaultHandler->AddArtDefinition(def_);
231 }
232 }
233
~ScopedDefinitionHandler()234 ~ScopedDefinitionHandler() {
235 if (is_lazy_) {
236 gTransformFaultHandler->RemoveDefinition(def_);
237 }
238 }
239
240 private:
241 ArtClassDefinition* def_;
242 bool is_lazy_;
243 };
244
245 // Initialize templates.
246 template
247 void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookNonRetransformable>(
248 EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
249 template
250 void Transformer::TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookRetransformable>(
251 EventHandler* event_handler, art::Thread* self, /*in-out*/ArtClassDefinition* def);
252
253 template<ArtJvmtiEvent kEvent>
TransformSingleClassDirect(EventHandler * event_handler,art::Thread * self,ArtClassDefinition * def)254 void Transformer::TransformSingleClassDirect(EventHandler* event_handler,
255 art::Thread* self,
256 /*in-out*/ArtClassDefinition* def) {
257 static_assert(kEvent == ArtJvmtiEvent::kClassFileLoadHookNonRetransformable ||
258 kEvent == ArtJvmtiEvent::kClassFileLoadHookRetransformable,
259 "bad event type");
260 // We don't want to do transitions between calling the event and setting the new data so change to
261 // native state early. This also avoids any problems that the FaultHandler might have in
262 // determining if an access to the dex_data is from generated code or not.
263 art::ScopedThreadStateChange stsc(self, art::ThreadState::kNative);
264 ScopedDefinitionHandler handler(def);
265 jint new_len = -1;
266 unsigned char* new_data = nullptr;
267 art::ArrayRef<const unsigned char> dex_data = def->GetDexData();
268 event_handler->DispatchEvent<kEvent>(
269 self,
270 static_cast<JNIEnv*>(self->GetJniEnv()),
271 def->GetClass(),
272 def->GetLoader(),
273 def->GetName().c_str(),
274 def->GetProtectionDomain(),
275 static_cast<jint>(dex_data.size()),
276 dex_data.data(),
277 /*out*/&new_len,
278 /*out*/&new_data);
279 def->SetNewDexData(new_len, new_data);
280 }
281
RetransformClassesDirect(EventHandler * event_handler,art::Thread * self,std::vector<ArtClassDefinition> * definitions)282 jvmtiError Transformer::RetransformClassesDirect(
283 EventHandler* event_handler,
284 art::Thread* self,
285 /*in-out*/std::vector<ArtClassDefinition>* definitions) {
286 for (ArtClassDefinition& def : *definitions) {
287 TransformSingleClassDirect<ArtJvmtiEvent::kClassFileLoadHookRetransformable>(event_handler,
288 self,
289 &def);
290 }
291 return OK;
292 }
293
RetransformClasses(ArtJvmTiEnv * env,EventHandler * event_handler,art::Runtime * runtime,art::Thread * self,jint class_count,const jclass * classes,std::string * error_msg)294 jvmtiError Transformer::RetransformClasses(ArtJvmTiEnv* env,
295 EventHandler* event_handler,
296 art::Runtime* runtime,
297 art::Thread* self,
298 jint class_count,
299 const jclass* classes,
300 /*out*/std::string* error_msg) {
301 if (env == nullptr) {
302 *error_msg = "env was null!";
303 return ERR(INVALID_ENVIRONMENT);
304 } else if (class_count < 0) {
305 *error_msg = "class_count was less then 0";
306 return ERR(ILLEGAL_ARGUMENT);
307 } else if (class_count == 0) {
308 // We don't actually need to do anything. Just return OK.
309 return OK;
310 } else if (classes == nullptr) {
311 *error_msg = "null classes!";
312 return ERR(NULL_POINTER);
313 }
314 // A holder that will Deallocate all the class bytes buffers on destruction.
315 std::vector<ArtClassDefinition> definitions;
316 jvmtiError res = OK;
317 for (jint i = 0; i < class_count; i++) {
318 res = Redefiner::GetClassRedefinitionError(classes[i], error_msg);
319 if (res != OK) {
320 return res;
321 }
322 ArtClassDefinition def;
323 res = def.Init(self, classes[i]);
324 if (res != OK) {
325 return res;
326 }
327 definitions.push_back(std::move(def));
328 }
329 res = RetransformClassesDirect(event_handler, self, &definitions);
330 if (res != OK) {
331 return res;
332 }
333 return Redefiner::RedefineClassesDirect(env, runtime, self, definitions, error_msg);
334 }
335
336 // TODO Move this somewhere else, ti_class?
GetClassLocation(ArtJvmTiEnv * env,jclass klass,std::string * location)337 jvmtiError GetClassLocation(ArtJvmTiEnv* env, jclass klass, /*out*/std::string* location) {
338 JNIEnv* jni_env = nullptr;
339 jint ret = env->art_vm->GetEnv(reinterpret_cast<void**>(&jni_env), JNI_VERSION_1_1);
340 if (ret != JNI_OK) {
341 // TODO Different error might be better?
342 return ERR(INTERNAL);
343 }
344 art::ScopedObjectAccess soa(jni_env);
345 art::StackHandleScope<1> hs(art::Thread::Current());
346 art::Handle<art::mirror::Class> hs_klass(hs.NewHandle(soa.Decode<art::mirror::Class>(klass)));
347 const art::DexFile& dex = hs_klass->GetDexFile();
348 *location = dex.GetLocation();
349 return OK;
350 }
351
352 } // namespace openjdkjvmti
353