class_loader_context.cc revision 095c6c96236476b605b3ac672f6d2b8c151e9479
1/* 2 * Copyright (C) 2017 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#include "class_loader_context.h" 18 19#include <stdlib.h> 20 21#include "android-base/file.h" 22#include "art_field-inl.h" 23#include "base/dchecked_vector.h" 24#include "base/stl_util.h" 25#include "class_linker.h" 26#include "class_loader_utils.h" 27#include "dex_file.h" 28#include "dex_file_loader.h" 29#include "handle_scope-inl.h" 30#include "jni_internal.h" 31#include "oat_file_assistant.h" 32#include "obj_ptr-inl.h" 33#include "runtime.h" 34#include "scoped_thread_state_change-inl.h" 35#include "thread.h" 36#include "well_known_classes.h" 37 38namespace art { 39 40static constexpr char kPathClassLoaderString[] = "PCL"; 41static constexpr char kDelegateLastClassLoaderString[] = "DLC"; 42static constexpr char kClassLoaderOpeningMark = '['; 43static constexpr char kClassLoaderClosingMark = ']'; 44static constexpr char kClassLoaderSeparator = ';'; 45static constexpr char kClasspathSeparator = ':'; 46static constexpr char kDexFileChecksumSeparator = '*'; 47 48ClassLoaderContext::ClassLoaderContext() 49 : special_shared_library_(false), 50 dex_files_open_attempted_(false), 51 dex_files_open_result_(false), 52 owns_the_dex_files_(true) {} 53 54ClassLoaderContext::ClassLoaderContext(bool owns_the_dex_files) 55 : special_shared_library_(false), 56 dex_files_open_attempted_(true), 57 dex_files_open_result_(true), 58 owns_the_dex_files_(owns_the_dex_files) {} 59 60ClassLoaderContext::~ClassLoaderContext() { 61 if (!owns_the_dex_files_) { 62 // If the context does not own the dex/oat files release the unique pointers to 63 // make sure we do not de-allocate them. 64 for (ClassLoaderInfo& info : class_loader_chain_) { 65 for (std::unique_ptr<OatFile>& oat_file : info.opened_oat_files) { 66 oat_file.release(); 67 } 68 for (std::unique_ptr<const DexFile>& dex_file : info.opened_dex_files) { 69 dex_file.release(); 70 } 71 } 72 } 73} 74 75std::unique_ptr<ClassLoaderContext> ClassLoaderContext::Default() { 76 return Create(""); 77} 78 79std::unique_ptr<ClassLoaderContext> ClassLoaderContext::Create(const std::string& spec) { 80 std::unique_ptr<ClassLoaderContext> result(new ClassLoaderContext()); 81 if (result->Parse(spec)) { 82 return result; 83 } else { 84 return nullptr; 85 } 86} 87 88// The expected format is: "ClassLoaderType1[ClasspathElem1*Checksum1:ClasspathElem2*Checksum2...]". 89// The checksum part of the format is expected only if parse_cheksums is true. 90bool ClassLoaderContext::ParseClassLoaderSpec(const std::string& class_loader_spec, 91 ClassLoaderType class_loader_type, 92 bool parse_checksums) { 93 const char* class_loader_type_str = GetClassLoaderTypeName(class_loader_type); 94 size_t type_str_size = strlen(class_loader_type_str); 95 96 CHECK_EQ(0, class_loader_spec.compare(0, type_str_size, class_loader_type_str)); 97 98 // Check the opening and closing markers. 99 if (class_loader_spec[type_str_size] != kClassLoaderOpeningMark) { 100 return false; 101 } 102 if (class_loader_spec[class_loader_spec.length() - 1] != kClassLoaderClosingMark) { 103 return false; 104 } 105 106 // At this point we know the format is ok; continue and extract the classpath. 107 // Note that class loaders with an empty class path are allowed. 108 std::string classpath = class_loader_spec.substr(type_str_size + 1, 109 class_loader_spec.length() - type_str_size - 2); 110 111 class_loader_chain_.push_back(ClassLoaderInfo(class_loader_type)); 112 113 if (!parse_checksums) { 114 Split(classpath, kClasspathSeparator, &class_loader_chain_.back().classpath); 115 } else { 116 std::vector<std::string> classpath_elements; 117 Split(classpath, kClasspathSeparator, &classpath_elements); 118 for (const std::string& element : classpath_elements) { 119 std::vector<std::string> dex_file_with_checksum; 120 Split(element, kDexFileChecksumSeparator, &dex_file_with_checksum); 121 if (dex_file_with_checksum.size() != 2) { 122 return false; 123 } 124 uint32_t checksum = 0; 125 if (!ParseInt(dex_file_with_checksum[1].c_str(), &checksum)) { 126 return false; 127 } 128 class_loader_chain_.back().classpath.push_back(dex_file_with_checksum[0]); 129 class_loader_chain_.back().checksums.push_back(checksum); 130 } 131 } 132 133 return true; 134} 135 136// Extracts the class loader type from the given spec. 137// Return ClassLoaderContext::kInvalidClassLoader if the class loader type is not 138// recognized. 139ClassLoaderContext::ClassLoaderType 140ClassLoaderContext::ExtractClassLoaderType(const std::string& class_loader_spec) { 141 const ClassLoaderType kValidTypes[] = {kPathClassLoader, kDelegateLastClassLoader}; 142 for (const ClassLoaderType& type : kValidTypes) { 143 const char* type_str = GetClassLoaderTypeName(type); 144 if (class_loader_spec.compare(0, strlen(type_str), type_str) == 0) { 145 return type; 146 } 147 } 148 return kInvalidClassLoader; 149} 150 151// The format: ClassLoaderType1[ClasspathElem1:ClasspathElem2...];ClassLoaderType2[...]... 152// ClassLoaderType is either "PCL" (PathClassLoader) or "DLC" (DelegateLastClassLoader). 153// ClasspathElem is the path of dex/jar/apk file. 154bool ClassLoaderContext::Parse(const std::string& spec, bool parse_checksums) { 155 if (spec.empty()) { 156 // By default we load the dex files in a PathClassLoader. 157 // So an empty spec is equivalent to an empty PathClassLoader (this happens when running 158 // tests) 159 class_loader_chain_.push_back(ClassLoaderInfo(kPathClassLoader)); 160 return true; 161 } 162 163 // Stop early if we detect the special shared library, which may be passed as the classpath 164 // for dex2oat when we want to skip the shared libraries check. 165 if (spec == OatFile::kSpecialSharedLibrary) { 166 LOG(INFO) << "The ClassLoaderContext is a special shared library."; 167 special_shared_library_ = true; 168 return true; 169 } 170 171 std::vector<std::string> class_loaders; 172 Split(spec, kClassLoaderSeparator, &class_loaders); 173 174 for (const std::string& class_loader : class_loaders) { 175 ClassLoaderType type = ExtractClassLoaderType(class_loader); 176 if (type == kInvalidClassLoader) { 177 LOG(ERROR) << "Invalid class loader type: " << class_loader; 178 return false; 179 } 180 if (!ParseClassLoaderSpec(class_loader, type, parse_checksums)) { 181 LOG(ERROR) << "Invalid class loader spec: " << class_loader; 182 return false; 183 } 184 } 185 return true; 186} 187 188// Opens requested class path files and appends them to opened_dex_files. If the dex files have 189// been stripped, this opens them from their oat files (which get added to opened_oat_files). 190bool ClassLoaderContext::OpenDexFiles(InstructionSet isa, const std::string& classpath_dir) { 191 if (dex_files_open_attempted_) { 192 // Do not attempt to re-open the files if we already tried. 193 return dex_files_open_result_; 194 } 195 196 dex_files_open_attempted_ = true; 197 // Assume we can open all dex files. If not, we will set this to false as we go. 198 dex_files_open_result_ = true; 199 200 if (special_shared_library_) { 201 // Nothing to open if the context is a special shared library. 202 return true; 203 } 204 205 // Note that we try to open all dex files even if some fail. 206 // We may get resource-only apks which we cannot load. 207 // TODO(calin): Refine the dex opening interface to be able to tell if an archive contains 208 // no dex files. So that we can distinguish the real failures... 209 for (ClassLoaderInfo& info : class_loader_chain_) { 210 size_t opened_dex_files_index = info.opened_dex_files.size(); 211 for (const std::string& cp_elem : info.classpath) { 212 // If path is relative, append it to the provided base directory. 213 std::string raw_location = cp_elem; 214 if (raw_location[0] != '/' && !classpath_dir.empty()) { 215 raw_location = classpath_dir + '/' + raw_location; 216 } 217 218 std::string location; // the real location of the class path element. 219 220 if (!android::base::Realpath(raw_location, &location)) { 221 // If we can't get the realpath of the location there might be something wrong with the 222 // classpath (maybe the file was deleted). 223 // Do not continue in this case and return false. 224 PLOG(WARNING) << "Could not get the realpath of dex location " << raw_location; 225 return false; 226 } 227 228 std::string error_msg; 229 // When opening the dex files from the context we expect their checksum to match their 230 // contents. So pass true to verify_checksum. 231 if (!DexFileLoader::Open(location.c_str(), 232 location.c_str(), 233 /*verify*/ true, 234 /*verify_checksum*/ true, 235 &error_msg, 236 &info.opened_dex_files)) { 237 // If we fail to open the dex file because it's been stripped, try to open the dex file 238 // from its corresponding oat file. 239 // This could happen when we need to recompile a pre-build whose dex code has been stripped. 240 // (for example, if the pre-build is only quicken and we want to re-compile it 241 // speed-profile). 242 // TODO(calin): Use the vdex directly instead of going through the oat file. 243 OatFileAssistant oat_file_assistant(location.c_str(), isa, false); 244 std::unique_ptr<OatFile> oat_file(oat_file_assistant.GetBestOatFile()); 245 std::vector<std::unique_ptr<const DexFile>> oat_dex_files; 246 if (oat_file != nullptr && 247 OatFileAssistant::LoadDexFiles(*oat_file, location, &oat_dex_files)) { 248 info.opened_oat_files.push_back(std::move(oat_file)); 249 info.opened_dex_files.insert(info.opened_dex_files.end(), 250 std::make_move_iterator(oat_dex_files.begin()), 251 std::make_move_iterator(oat_dex_files.end())); 252 } else { 253 LOG(WARNING) << "Could not open dex files from location: " << location; 254 dex_files_open_result_ = false; 255 } 256 } 257 } 258 259 // We finished opening the dex files from the classpath. 260 // Now update the classpath and the checksum with the locations of the dex files. 261 // 262 // We do this because initially the classpath contains the paths of the dex files; and 263 // some of them might be multi-dexes. So in order to have a consistent view we replace all the 264 // file paths with the actual dex locations being loaded. 265 // This will allow the context to VerifyClassLoaderContextMatch which expects or multidex 266 // location in the class paths. 267 // Note that this will also remove the paths that could not be opened. 268 info.classpath.clear(); 269 info.checksums.clear(); 270 for (size_t k = opened_dex_files_index; k < info.opened_dex_files.size(); k++) { 271 std::unique_ptr<const DexFile>& dex = info.opened_dex_files[k]; 272 info.classpath.push_back(dex->GetLocation()); 273 info.checksums.push_back(dex->GetLocationChecksum()); 274 } 275 } 276 277 return dex_files_open_result_; 278} 279 280bool ClassLoaderContext::RemoveLocationsFromClassPaths( 281 const dchecked_vector<std::string>& locations) { 282 CHECK(!dex_files_open_attempted_) 283 << "RemoveLocationsFromClasspaths cannot be call after OpenDexFiles"; 284 285 std::set<std::string> canonical_locations; 286 for (const std::string& location : locations) { 287 canonical_locations.insert(DexFileLoader::GetDexCanonicalLocation(location.c_str())); 288 } 289 bool removed_locations = false; 290 for (ClassLoaderInfo& info : class_loader_chain_) { 291 size_t initial_size = info.classpath.size(); 292 auto kept_it = std::remove_if( 293 info.classpath.begin(), 294 info.classpath.end(), 295 [canonical_locations](const std::string& location) { 296 return ContainsElement(canonical_locations, 297 DexFileLoader::GetDexCanonicalLocation(location.c_str())); 298 }); 299 info.classpath.erase(kept_it, info.classpath.end()); 300 if (initial_size != info.classpath.size()) { 301 removed_locations = true; 302 } 303 } 304 return removed_locations; 305} 306 307std::string ClassLoaderContext::EncodeContextForDex2oat(const std::string& base_dir) const { 308 return EncodeContext(base_dir, /*for_dex2oat*/ true); 309} 310 311std::string ClassLoaderContext::EncodeContextForOatFile(const std::string& base_dir) const { 312 return EncodeContext(base_dir, /*for_dex2oat*/ false); 313} 314 315std::string ClassLoaderContext::EncodeContext(const std::string& base_dir, 316 bool for_dex2oat) const { 317 CheckDexFilesOpened("EncodeContextForOatFile"); 318 if (special_shared_library_) { 319 return OatFile::kSpecialSharedLibrary; 320 } 321 322 std::ostringstream out; 323 if (class_loader_chain_.empty()) { 324 // We can get in this situation if the context was created with a class path containing the 325 // source dex files which were later removed (happens during run-tests). 326 out << GetClassLoaderTypeName(kPathClassLoader) 327 << kClassLoaderOpeningMark 328 << kClassLoaderClosingMark; 329 return out.str(); 330 } 331 332 for (size_t i = 0; i < class_loader_chain_.size(); i++) { 333 const ClassLoaderInfo& info = class_loader_chain_[i]; 334 if (i > 0) { 335 out << kClassLoaderSeparator; 336 } 337 out << GetClassLoaderTypeName(info.type); 338 out << kClassLoaderOpeningMark; 339 std::set<std::string> seen_locations; 340 for (size_t k = 0; k < info.opened_dex_files.size(); k++) { 341 const std::unique_ptr<const DexFile>& dex_file = info.opened_dex_files[k]; 342 if (for_dex2oat) { 343 // dex2oat only needs the base location. It cannot accept multidex locations. 344 // So ensure we only add each file once. 345 bool new_insert = seen_locations.insert( 346 DexFileLoader::GetBaseLocation(dex_file->GetLocation())).second; 347 if (!new_insert) { 348 continue; 349 } 350 } 351 const std::string& location = dex_file->GetLocation(); 352 if (k > 0) { 353 out << kClasspathSeparator; 354 } 355 // Find paths that were relative and convert them back from absolute. 356 if (!base_dir.empty() && location.substr(0, base_dir.length()) == base_dir) { 357 out << location.substr(base_dir.length() + 1).c_str(); 358 } else { 359 out << dex_file->GetLocation().c_str(); 360 } 361 // dex2oat does not need the checksums. 362 if (!for_dex2oat) { 363 out << kDexFileChecksumSeparator; 364 out << dex_file->GetLocationChecksum(); 365 } 366 } 367 out << kClassLoaderClosingMark; 368 } 369 return out.str(); 370} 371 372jobject ClassLoaderContext::CreateClassLoader( 373 const std::vector<const DexFile*>& compilation_sources) const { 374 CheckDexFilesOpened("CreateClassLoader"); 375 376 Thread* self = Thread::Current(); 377 ScopedObjectAccess soa(self); 378 379 ClassLinker* const class_linker = Runtime::Current()->GetClassLinker(); 380 381 if (class_loader_chain_.empty()) { 382 return class_linker->CreatePathClassLoader(self, compilation_sources); 383 } 384 385 // Create the class loaders starting from the top most parent (the one on the last position 386 // in the chain) but omit the first class loader which will contain the compilation_sources and 387 // needs special handling. 388 jobject current_parent = nullptr; // the starting parent is the BootClassLoader. 389 for (size_t i = class_loader_chain_.size() - 1; i > 0; i--) { 390 std::vector<const DexFile*> class_path_files = MakeNonOwningPointerVector( 391 class_loader_chain_[i].opened_dex_files); 392 current_parent = class_linker->CreateWellKnownClassLoader( 393 self, 394 class_path_files, 395 GetClassLoaderClass(class_loader_chain_[i].type), 396 current_parent); 397 } 398 399 // We set up all the parents. Move on to create the first class loader. 400 // Its classpath comes first, followed by compilation sources. This ensures that whenever 401 // we need to resolve classes from it the classpath elements come first. 402 403 std::vector<const DexFile*> first_class_loader_classpath = MakeNonOwningPointerVector( 404 class_loader_chain_[0].opened_dex_files); 405 first_class_loader_classpath.insert(first_class_loader_classpath.end(), 406 compilation_sources.begin(), 407 compilation_sources.end()); 408 409 return class_linker->CreateWellKnownClassLoader( 410 self, 411 first_class_loader_classpath, 412 GetClassLoaderClass(class_loader_chain_[0].type), 413 current_parent); 414} 415 416std::vector<const DexFile*> ClassLoaderContext::FlattenOpenedDexFiles() const { 417 CheckDexFilesOpened("FlattenOpenedDexFiles"); 418 419 std::vector<const DexFile*> result; 420 for (const ClassLoaderInfo& info : class_loader_chain_) { 421 for (const std::unique_ptr<const DexFile>& dex_file : info.opened_dex_files) { 422 result.push_back(dex_file.get()); 423 } 424 } 425 return result; 426} 427 428const char* ClassLoaderContext::GetClassLoaderTypeName(ClassLoaderType type) { 429 switch (type) { 430 case kPathClassLoader: return kPathClassLoaderString; 431 case kDelegateLastClassLoader: return kDelegateLastClassLoaderString; 432 default: 433 LOG(FATAL) << "Invalid class loader type " << type; 434 UNREACHABLE(); 435 } 436} 437 438void ClassLoaderContext::CheckDexFilesOpened(const std::string& calling_method) const { 439 CHECK(dex_files_open_attempted_) 440 << "Dex files were not successfully opened before the call to " << calling_method 441 << "attempt=" << dex_files_open_attempted_ << ", result=" << dex_files_open_result_; 442} 443 444// Collects the dex files from the give Java dex_file object. Only the dex files with 445// at least 1 class are collected. If a null java_dex_file is passed this method does nothing. 446static bool CollectDexFilesFromJavaDexFile(ObjPtr<mirror::Object> java_dex_file, 447 ArtField* const cookie_field, 448 std::vector<const DexFile*>* out_dex_files) 449 REQUIRES_SHARED(Locks::mutator_lock_) { 450 if (java_dex_file == nullptr) { 451 return true; 452 } 453 // On the Java side, the dex files are stored in the cookie field. 454 mirror::LongArray* long_array = cookie_field->GetObject(java_dex_file)->AsLongArray(); 455 if (long_array == nullptr) { 456 // This should never happen so log a warning. 457 LOG(ERROR) << "Unexpected null cookie"; 458 return false; 459 } 460 int32_t long_array_size = long_array->GetLength(); 461 // Index 0 from the long array stores the oat file. The dex files start at index 1. 462 for (int32_t j = 1; j < long_array_size; ++j) { 463 const DexFile* cp_dex_file = reinterpret_cast<const DexFile*>(static_cast<uintptr_t>( 464 long_array->GetWithoutChecks(j))); 465 if (cp_dex_file != nullptr && cp_dex_file->NumClassDefs() > 0) { 466 // TODO(calin): It's unclear why the dex files with no classes are skipped here and when 467 // cp_dex_file can be null. 468 out_dex_files->push_back(cp_dex_file); 469 } 470 } 471 return true; 472} 473 474// Collects all the dex files loaded by the given class loader. 475// Returns true for success or false if an unexpected state is discovered (e.g. a null dex cookie, 476// a null list of dex elements or a null dex element). 477static bool CollectDexFilesFromSupportedClassLoader(ScopedObjectAccessAlreadyRunnable& soa, 478 Handle<mirror::ClassLoader> class_loader, 479 std::vector<const DexFile*>* out_dex_files) 480 REQUIRES_SHARED(Locks::mutator_lock_) { 481 CHECK(IsPathOrDexClassLoader(soa, class_loader) || IsDelegateLastClassLoader(soa, class_loader)); 482 483 // All supported class loaders inherit from BaseDexClassLoader. 484 // We need to get the DexPathList and loop through it. 485 ArtField* const cookie_field = 486 jni::DecodeArtField(WellKnownClasses::dalvik_system_DexFile_cookie); 487 ArtField* const dex_file_field = 488 jni::DecodeArtField(WellKnownClasses::dalvik_system_DexPathList__Element_dexFile); 489 ObjPtr<mirror::Object> dex_path_list = 490 jni::DecodeArtField(WellKnownClasses::dalvik_system_BaseDexClassLoader_pathList)-> 491 GetObject(class_loader.Get()); 492 CHECK(cookie_field != nullptr); 493 CHECK(dex_file_field != nullptr); 494 if (dex_path_list == nullptr) { 495 // This may be null if the current class loader is under construction and it does not 496 // have its fields setup yet. 497 return true; 498 } 499 // DexPathList has an array dexElements of Elements[] which each contain a dex file. 500 ObjPtr<mirror::Object> dex_elements_obj = 501 jni::DecodeArtField(WellKnownClasses::dalvik_system_DexPathList_dexElements)-> 502 GetObject(dex_path_list); 503 // Loop through each dalvik.system.DexPathList$Element's dalvik.system.DexFile and look 504 // at the mCookie which is a DexFile vector. 505 if (dex_elements_obj == nullptr) { 506 // TODO(calin): It's unclear if we should just assert here. For now be prepared for the worse 507 // and assume we have no elements. 508 return true; 509 } else { 510 StackHandleScope<1> hs(soa.Self()); 511 Handle<mirror::ObjectArray<mirror::Object>> dex_elements( 512 hs.NewHandle(dex_elements_obj->AsObjectArray<mirror::Object>())); 513 for (int32_t i = 0; i < dex_elements->GetLength(); ++i) { 514 mirror::Object* element = dex_elements->GetWithoutChecks(i); 515 if (element == nullptr) { 516 // Should never happen, log an error and break. 517 // TODO(calin): It's unclear if we should just assert here. 518 // This code was propagated to oat_file_manager from the class linker where it would 519 // throw a NPE. For now, return false which will mark this class loader as unsupported. 520 LOG(ERROR) << "Unexpected null in the dex element list"; 521 return false; 522 } 523 ObjPtr<mirror::Object> dex_file = dex_file_field->GetObject(element); 524 if (!CollectDexFilesFromJavaDexFile(dex_file, cookie_field, out_dex_files)) { 525 return false; 526 } 527 } 528 } 529 530 return true; 531} 532 533static bool GetDexFilesFromDexElementsArray( 534 ScopedObjectAccessAlreadyRunnable& soa, 535 Handle<mirror::ObjectArray<mirror::Object>> dex_elements, 536 std::vector<const DexFile*>* out_dex_files) REQUIRES_SHARED(Locks::mutator_lock_) { 537 DCHECK(dex_elements != nullptr); 538 539 ArtField* const cookie_field = 540 jni::DecodeArtField(WellKnownClasses::dalvik_system_DexFile_cookie); 541 ArtField* const dex_file_field = 542 jni::DecodeArtField(WellKnownClasses::dalvik_system_DexPathList__Element_dexFile); 543 ObjPtr<mirror::Class> const element_class = soa.Decode<mirror::Class>( 544 WellKnownClasses::dalvik_system_DexPathList__Element); 545 ObjPtr<mirror::Class> const dexfile_class = soa.Decode<mirror::Class>( 546 WellKnownClasses::dalvik_system_DexFile); 547 548 for (int32_t i = 0; i < dex_elements->GetLength(); ++i) { 549 mirror::Object* element = dex_elements->GetWithoutChecks(i); 550 // We can hit a null element here because this is invoked with a partially filled dex_elements 551 // array from DexPathList. DexPathList will open each dex sequentially, each time passing the 552 // list of dex files which were opened before. 553 if (element == nullptr) { 554 continue; 555 } 556 557 // We support this being dalvik.system.DexPathList$Element and dalvik.system.DexFile. 558 // TODO(calin): Code caried over oat_file_manager: supporting both classes seem to be 559 // a historical glitch. All the java code opens dex files using an array of Elements. 560 ObjPtr<mirror::Object> dex_file; 561 if (element_class == element->GetClass()) { 562 dex_file = dex_file_field->GetObject(element); 563 } else if (dexfile_class == element->GetClass()) { 564 dex_file = element; 565 } else { 566 LOG(ERROR) << "Unsupported element in dex_elements: " 567 << mirror::Class::PrettyClass(element->GetClass()); 568 return false; 569 } 570 571 if (!CollectDexFilesFromJavaDexFile(dex_file, cookie_field, out_dex_files)) { 572 return false; 573 } 574 } 575 return true; 576} 577 578// Adds the `class_loader` info to the `context`. 579// The dex file present in `dex_elements` array (if not null) will be added at the end of 580// the classpath. 581// This method is recursive (w.r.t. the class loader parent) and will stop once it reaches the 582// BootClassLoader. Note that the class loader chain is expected to be short. 583bool ClassLoaderContext::AddInfoToContextFromClassLoader( 584 ScopedObjectAccessAlreadyRunnable& soa, 585 Handle<mirror::ClassLoader> class_loader, 586 Handle<mirror::ObjectArray<mirror::Object>> dex_elements) 587 REQUIRES_SHARED(Locks::mutator_lock_) { 588 if (ClassLinker::IsBootClassLoader(soa, class_loader.Get())) { 589 // Nothing to do for the boot class loader as we don't add its dex files to the context. 590 return true; 591 } 592 593 ClassLoaderContext::ClassLoaderType type; 594 if (IsPathOrDexClassLoader(soa, class_loader)) { 595 type = kPathClassLoader; 596 } else if (IsDelegateLastClassLoader(soa, class_loader)) { 597 type = kDelegateLastClassLoader; 598 } else { 599 LOG(WARNING) << "Unsupported class loader"; 600 return false; 601 } 602 603 // Inspect the class loader for its dex files. 604 std::vector<const DexFile*> dex_files_loaded; 605 CollectDexFilesFromSupportedClassLoader(soa, class_loader, &dex_files_loaded); 606 607 // If we have a dex_elements array extract its dex elements now. 608 // This is used in two situations: 609 // 1) when a new ClassLoader is created DexPathList will open each dex file sequentially 610 // passing the list of already open dex files each time. This ensures that we see the 611 // correct context even if the ClassLoader under construction is not fully build. 612 // 2) when apk splits are loaded on the fly, the framework will load their dex files by 613 // appending them to the current class loader. When the new code paths are loaded in 614 // BaseDexClassLoader, the paths already present in the class loader will be passed 615 // in the dex_elements array. 616 if (dex_elements != nullptr) { 617 GetDexFilesFromDexElementsArray(soa, dex_elements, &dex_files_loaded); 618 } 619 620 class_loader_chain_.push_back(ClassLoaderContext::ClassLoaderInfo(type)); 621 ClassLoaderInfo& info = class_loader_chain_.back(); 622 for (const DexFile* dex_file : dex_files_loaded) { 623 info.classpath.push_back(dex_file->GetLocation()); 624 info.checksums.push_back(dex_file->GetLocationChecksum()); 625 info.opened_dex_files.emplace_back(dex_file); 626 } 627 628 // We created the ClassLoaderInfo for the current loader. Move on to its parent. 629 630 StackHandleScope<1> hs(Thread::Current()); 631 Handle<mirror::ClassLoader> parent = hs.NewHandle(class_loader->GetParent()); 632 633 // Note that dex_elements array is null here. The elements are considered to be part of the 634 // current class loader and are not passed to the parents. 635 ScopedNullHandle<mirror::ObjectArray<mirror::Object>> null_dex_elements; 636 return AddInfoToContextFromClassLoader(soa, parent, null_dex_elements); 637} 638 639std::unique_ptr<ClassLoaderContext> ClassLoaderContext::CreateContextForClassLoader( 640 jobject class_loader, 641 jobjectArray dex_elements) { 642 CHECK(class_loader != nullptr); 643 644 ScopedObjectAccess soa(Thread::Current()); 645 StackHandleScope<2> hs(soa.Self()); 646 Handle<mirror::ClassLoader> h_class_loader = 647 hs.NewHandle(soa.Decode<mirror::ClassLoader>(class_loader)); 648 Handle<mirror::ObjectArray<mirror::Object>> h_dex_elements = 649 hs.NewHandle(soa.Decode<mirror::ObjectArray<mirror::Object>>(dex_elements)); 650 651 std::unique_ptr<ClassLoaderContext> result(new ClassLoaderContext(/*owns_the_dex_files*/ false)); 652 if (result->AddInfoToContextFromClassLoader(soa, h_class_loader, h_dex_elements)) { 653 return result; 654 } else { 655 return nullptr; 656 } 657} 658 659static bool IsAbsoluteLocation(const std::string& location) { 660 return !location.empty() && location[0] == '/'; 661} 662 663bool ClassLoaderContext::VerifyClassLoaderContextMatch(const std::string& context_spec) const { 664 DCHECK(dex_files_open_attempted_); 665 DCHECK(dex_files_open_result_); 666 667 ClassLoaderContext expected_context; 668 if (!expected_context.Parse(context_spec, /*parse_checksums*/ true)) { 669 LOG(WARNING) << "Invalid class loader context: " << context_spec; 670 return false; 671 } 672 673 // Special shared library contexts always match. They essentially instruct the runtime 674 // to ignore the class path check because the oat file is known to be loaded in different 675 // contexts. OatFileManager will further verify if the oat file can be loaded based on the 676 // collision check. 677 if (special_shared_library_ || expected_context.special_shared_library_) { 678 return true; 679 } 680 681 if (expected_context.class_loader_chain_.size() != class_loader_chain_.size()) { 682 LOG(WARNING) << "ClassLoaderContext size mismatch. expected=" 683 << expected_context.class_loader_chain_.size() 684 << ", actual=" << class_loader_chain_.size() 685 << " (" << context_spec << " | " << EncodeContextForOatFile("") << ")"; 686 return false; 687 } 688 689 for (size_t i = 0; i < class_loader_chain_.size(); i++) { 690 const ClassLoaderInfo& info = class_loader_chain_[i]; 691 const ClassLoaderInfo& expected_info = expected_context.class_loader_chain_[i]; 692 if (info.type != expected_info.type) { 693 LOG(WARNING) << "ClassLoaderContext type mismatch for position " << i 694 << ". expected=" << GetClassLoaderTypeName(expected_info.type) 695 << ", found=" << GetClassLoaderTypeName(info.type) 696 << " (" << context_spec << " | " << EncodeContextForOatFile("") << ")"; 697 return false; 698 } 699 if (info.classpath.size() != expected_info.classpath.size()) { 700 LOG(WARNING) << "ClassLoaderContext classpath size mismatch for position " << i 701 << ". expected=" << expected_info.classpath.size() 702 << ", found=" << info.classpath.size() 703 << " (" << context_spec << " | " << EncodeContextForOatFile("") << ")"; 704 return false; 705 } 706 707 DCHECK_EQ(info.classpath.size(), info.checksums.size()); 708 DCHECK_EQ(expected_info.classpath.size(), expected_info.checksums.size()); 709 710 for (size_t k = 0; k < info.classpath.size(); k++) { 711 // Compute the dex location that must be compared. 712 // We shouldn't do a naive comparison `info.classpath[k] == expected_info.classpath[k]` 713 // because even if they refer to the same file, one could be encoded as a relative location 714 // and the other as an absolute one. 715 bool is_dex_name_absolute = IsAbsoluteLocation(info.classpath[k]); 716 bool is_expected_dex_name_absolute = IsAbsoluteLocation(expected_info.classpath[k]); 717 std::string dex_name; 718 std::string expected_dex_name; 719 720 if (is_dex_name_absolute == is_expected_dex_name_absolute) { 721 // If both locations are absolute or relative then compare them as they are. 722 // This is usually the case for: shared libraries and secondary dex files. 723 dex_name = info.classpath[k]; 724 expected_dex_name = expected_info.classpath[k]; 725 } else if (is_dex_name_absolute) { 726 // The runtime name is absolute but the compiled name (the expected one) is relative. 727 // This is the case for split apks which depend on base or on other splits. 728 dex_name = info.classpath[k]; 729 expected_dex_name = OatFile::ResolveRelativeEncodedDexLocation( 730 info.classpath[k].c_str(), expected_info.classpath[k]); 731 } else { 732 // The runtime name is relative but the compiled name is absolute. 733 // There is no expected use case that would end up here as dex files are always loaded 734 // with their absolute location. However, be tolerant and do the best effort (in case 735 // there are unexpected new use case...). 736 DCHECK(is_expected_dex_name_absolute); 737 dex_name = OatFile::ResolveRelativeEncodedDexLocation( 738 expected_info.classpath[k].c_str(), info.classpath[k]); 739 expected_dex_name = expected_info.classpath[k]; 740 } 741 742 // Compare the locations. 743 if (dex_name != expected_dex_name) { 744 LOG(WARNING) << "ClassLoaderContext classpath element mismatch for position " << i 745 << ". expected=" << expected_info.classpath[k] 746 << ", found=" << info.classpath[k] 747 << " (" << context_spec << " | " << EncodeContextForOatFile("") << ")"; 748 return false; 749 } 750 751 // Compare the checksums. 752 if (info.checksums[k] != expected_info.checksums[k]) { 753 LOG(WARNING) << "ClassLoaderContext classpath element checksum mismatch for position " << i 754 << ". expected=" << expected_info.checksums[k] 755 << ", found=" << info.checksums[k] 756 << " (" << context_spec << " | " << EncodeContextForOatFile("") << ")"; 757 return false; 758 } 759 } 760 } 761 return true; 762} 763 764jclass ClassLoaderContext::GetClassLoaderClass(ClassLoaderType type) { 765 switch (type) { 766 case kPathClassLoader: return WellKnownClasses::dalvik_system_PathClassLoader; 767 case kDelegateLastClassLoader: return WellKnownClasses::dalvik_system_DelegateLastClassLoader; 768 case kInvalidClassLoader: break; // will fail after the switch. 769 } 770 LOG(FATAL) << "Invalid class loader type " << type; 771 UNREACHABLE(); 772} 773 774} // namespace art 775 776