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