libdexfile/dex/dex_file_loader.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "dex_file_loader.h"

 #include "android-base/stringprintf.h"

 #include "base/stl_util.h"
 #include "compact_dex_file.h"
 #include "dex_file.h"
 #include "dex_file_verifier.h"
 #include "standard_dex_file.h"
 #include "ziparchive/zip_archive.h"

 namespace art {

 namespace {

 class VectorContainer : public DexFileContainer {
  public:
   explicit VectorContainer(std::vector<uint8_t>&& vector) : vector_(std::move(vector)) { }
   ~VectorContainer() override { }

   int GetPermissions() override {
     return 0;
   }

   bool IsReadOnly() override {
     return true;
   }

   bool EnableWrite() override {
     return false;
   }

   bool DisableWrite() override {
     return false;
   }

  private:
   std::vector<uint8_t> vector_;
   DISALLOW_COPY_AND_ASSIGN(VectorContainer);
 };

 }  // namespace

 using android::base::StringPrintf;

 class DexZipArchive;

 class DexZipEntry {
  public:
   // Extract this entry to memory.
   // Returns null on failure and sets error_msg.
   const std::vector<uint8_t> Extract(std::string* error_msg) {
     std::vector<uint8_t> map(GetUncompressedLength());
     if (map.size() == 0) {
       DCHECK(!error_msg->empty());
       return map;
     }
     const int32_t error = ExtractToMemory(handle_, zip_entry_, map.data(), map.size());
     if (error) {
       *error_msg = std::string(ErrorCodeString(error));
     }
     return map;
   }

   virtual ~DexZipEntry() {
     delete zip_entry_;
   }

   uint32_t GetUncompressedLength() {
     return zip_entry_->uncompressed_length;
   }

   uint32_t GetCrc32() {
     return zip_entry_->crc32;
   }

  private:
   DexZipEntry(ZipArchiveHandle handle,
               ::ZipEntry* zip_entry,
            const std::string& entry_name)
     : handle_(handle), zip_entry_(zip_entry), entry_name_(entry_name) {}

   ZipArchiveHandle handle_;
   ::ZipEntry* const zip_entry_;
   std::string const entry_name_;

   friend class DexZipArchive;
   DISALLOW_COPY_AND_ASSIGN(DexZipEntry);
 };

 class DexZipArchive {
  public:
   // return new DexZipArchive instance on success, null on error.
   static DexZipArchive* Open(const uint8_t* base, size_t size, std::string* error_msg) {
     ZipArchiveHandle handle;
     uint8_t* nonconst_base = const_cast<uint8_t*>(base);
     const int32_t error = OpenArchiveFromMemory(nonconst_base, size, "ZipArchiveMemory", &handle);
     if (error) {
       *error_msg = std::string(ErrorCodeString(error));
       CloseArchive(handle);
       return nullptr;
     }
     return new DexZipArchive(handle);
   }

   DexZipEntry* Find(const char* name, std::string* error_msg) const {
     DCHECK(name != nullptr);
     // Resist the urge to delete the space. <: is a bigraph sequence.
     std::unique_ptr< ::ZipEntry> zip_entry(new ::ZipEntry);
     const int32_t error = FindEntry(handle_, ZipString(name), zip_entry.get());
     if (error) {
       *error_msg = std::string(ErrorCodeString(error));
       return nullptr;
     }
     return new DexZipEntry(handle_, zip_entry.release(), name);
   }

   ~DexZipArchive() {
     CloseArchive(handle_);
   }


  private:
   explicit DexZipArchive(ZipArchiveHandle handle) : handle_(handle) {}
   ZipArchiveHandle handle_;

   friend class DexZipEntry;
   DISALLOW_COPY_AND_ASSIGN(DexZipArchive);
 };

 static bool IsZipMagic(uint32_t magic) {
   return (('P' == ((magic >> 0) & 0xff)) &&
           ('K' == ((magic >> 8) & 0xff)));
 }

 bool DexFileLoader::IsMagicValid(uint32_t magic) {
   return IsMagicValid(reinterpret_cast<uint8_t*>(&magic));
 }

 bool DexFileLoader::IsMagicValid(const uint8_t* magic) {
   return StandardDexFile::IsMagicValid(magic) ||
       CompactDexFile::IsMagicValid(magic);
 }

 bool DexFileLoader::IsVersionAndMagicValid(const uint8_t* magic) {
   if (StandardDexFile::IsMagicValid(magic)) {
     return StandardDexFile::IsVersionValid(magic);
   }
   if (CompactDexFile::IsMagicValid(magic)) {
     return CompactDexFile::IsVersionValid(magic);
   }
   return false;
 }

 bool DexFileLoader::IsMultiDexLocation(const char* location) {
   return strrchr(location, kMultiDexSeparator) != nullptr;
 }

 std::string DexFileLoader::GetMultiDexClassesDexName(size_t index) {
   return (index == 0) ? "classes.dex" : StringPrintf("classes%zu.dex", index + 1);
 }

 std::string DexFileLoader::GetMultiDexLocation(size_t index, const char* dex_location) {
   return (index == 0)
       ? dex_location
       : StringPrintf("%s%cclasses%zu.dex", dex_location, kMultiDexSeparator, index + 1);
 }

 std::string DexFileLoader::GetDexCanonicalLocation(const char* dex_location) {
   CHECK_NE(dex_location, static_cast<const char*>(nullptr));
   std::string base_location = GetBaseLocation(dex_location);
   const char* suffix = dex_location + base_location.size();
   DCHECK(suffix[0] == 0 || suffix[0] == kMultiDexSeparator);
 #ifdef _WIN32
   // Warning: No symbolic link processing here.
   PLOG(WARNING) << "realpath is unsupported on Windows.";
 #else
   // Warning: Bionic implementation of realpath() allocates > 12KB on the stack.
   // Do not run this code on a small stack, e.g. in signal handler.
   UniqueCPtr<const char[]> path(realpath(base_location.c_str(), nullptr));
   if (path != nullptr && path.get() != base_location) {
     return std::string(path.get()) + suffix;
   }
 #endif
   if (suffix[0] == 0) {
     return base_location;
   } else {
     return dex_location;
   }
 }

 // All of the implementations here should be independent of the runtime.
 // TODO: implement all the virtual methods.

 bool DexFileLoader::GetMultiDexChecksums(
     const char* filename ATTRIBUTE_UNUSED,
     std::vector<uint32_t>* checksums ATTRIBUTE_UNUSED,
     std::string* error_msg,
     int zip_fd ATTRIBUTE_UNUSED,
     bool* zip_file_only_contains_uncompress_dex ATTRIBUTE_UNUSED) const {
   *error_msg = "UNIMPLEMENTED";
   return false;
 }

 std::unique_ptr<const DexFile> DexFileLoader::Open(
     const uint8_t* base,
     size_t size,
     const std::string& location,
     uint32_t location_checksum,
     const OatDexFile* oat_dex_file,
     bool verify,
     bool verify_checksum,
     std::string* error_msg,
     std::unique_ptr<DexFileContainer> container) const {
   return OpenCommon(base,
                     size,
                     /*data_base=*/ nullptr,
                     /*data_size=*/ 0,
                     location,
                     location_checksum,
                     oat_dex_file,
                     verify,
                     verify_checksum,
                     error_msg,
                     std::move(container),
                     /*verify_result=*/ nullptr);
 }

 std::unique_ptr<const DexFile> DexFileLoader::OpenWithDataSection(
     const uint8_t* base,
     size_t size,
     const uint8_t* data_base,
     size_t data_size,
     const std::string& location,
     uint32_t location_checksum,
     const OatDexFile* oat_dex_file,
     bool verify,
     bool verify_checksum,
     std::string* error_msg) const {
   return OpenCommon(base,
                     size,
                     data_base,
                     data_size,
                     location,
                     location_checksum,
                     oat_dex_file,
                     verify,
                     verify_checksum,
                     error_msg,
                     /*container=*/ nullptr,
                     /*verify_result=*/ nullptr);
 }

 bool DexFileLoader::OpenAll(
     const uint8_t* base,
     size_t size,
     const std::string& location,
     bool verify,
     bool verify_checksum,
     DexFileLoaderErrorCode* error_code,
     std::string* error_msg,
     std::vector<std::unique_ptr<const DexFile>>* dex_files) const {
   DCHECK(dex_files != nullptr) << "DexFile::Open: out-param is nullptr";
   uint32_t magic = *reinterpret_cast<const uint32_t*>(base);
   if (IsZipMagic(magic)) {
     std::unique_ptr<DexZipArchive> zip_archive(DexZipArchive::Open(base, size, error_msg));
     if (zip_archive.get() == nullptr) {
       DCHECK(!error_msg->empty());
       return false;
     }
     return OpenAllDexFilesFromZip(*zip_archive.get(),
                                   location,
                                   verify,
                                   verify_checksum,
                                   error_code,
                                   error_msg,
                                   dex_files);
   }
   if (IsMagicValid(magic)) {
     const DexFile::Header* dex_header = reinterpret_cast<const DexFile::Header*>(base);
     std::unique_ptr<const DexFile> dex_file(Open(base,
                                                  size,
                                                  location,
                                                  dex_header->checksum_,
                                                  /*oat_dex_file=*/ nullptr,
                                                  verify,
                                                  verify_checksum,
                                                  error_msg));
     if (dex_file.get() != nullptr) {
       dex_files->push_back(std::move(dex_file));
       return true;
     } else {
       return false;
     }
   }
   *error_msg = StringPrintf("Expected valid zip or dex file");
   return false;
 }

 std::unique_ptr<DexFile> DexFileLoader::OpenCommon(const uint8_t* base,
                                                    size_t size,
                                                    const uint8_t* data_base,
                                                    size_t data_size,
                                                    const std::string& location,
                                                    uint32_t location_checksum,
                                                    const OatDexFile* oat_dex_file,
                                                    bool verify,
                                                    bool verify_checksum,
                                                    std::string* error_msg,
                                                    std::unique_ptr<DexFileContainer> container,
                                                    VerifyResult* verify_result) {
   if (verify_result != nullptr) {
     *verify_result = VerifyResult::kVerifyNotAttempted;
   }
   std::unique_ptr<DexFile> dex_file;
   if (size >= sizeof(StandardDexFile::Header) && StandardDexFile::IsMagicValid(base)) {
     if (data_size != 0) {
       CHECK_EQ(base, data_base) << "Unsupported for standard dex";
     }
     dex_file.reset(new StandardDexFile(base,
                                        size,
                                        location,
                                        location_checksum,
                                        oat_dex_file,
                                        std::move(container)));
   } else if (size >= sizeof(CompactDexFile::Header) && CompactDexFile::IsMagicValid(base)) {
     if (data_base == nullptr) {
       // TODO: Is there a clean way to support both an explicit data section and reading the one
       // from the header.
       CHECK_EQ(data_size, 0u);
       const CompactDexFile::Header* const header = CompactDexFile::Header::At(base);
       data_base = base + header->data_off_;
       data_size = header->data_size_;
     }
     dex_file.reset(new CompactDexFile(base,
                                       size,
                                       data_base,
                                       data_size,
                                       location,
                                       location_checksum,
                                       oat_dex_file,
                                       std::move(container)));
     // Disable verification for CompactDex input.
     verify = false;
   } else {
     *error_msg = "Invalid or truncated dex file";
   }
   if (dex_file == nullptr) {
     *error_msg = StringPrintf("Failed to open dex file '%s' from memory: %s", location.c_str(),
                               error_msg->c_str());
     return nullptr;
   }
   if (!dex_file->Init(error_msg)) {
     dex_file.reset();
     return nullptr;
   }
   if (verify && !DexFileVerifier::Verify(dex_file.get(),
                                          dex_file->Begin(),
                                          dex_file->Size(),
                                          location.c_str(),
                                          verify_checksum,
                                          error_msg)) {
     if (verify_result != nullptr) {
       *verify_result = VerifyResult::kVerifyFailed;
     }
     return nullptr;
   }
   if (verify_result != nullptr) {
     *verify_result = VerifyResult::kVerifySucceeded;
   }
   return dex_file;
 }

 std::unique_ptr<const DexFile> DexFileLoader::OpenOneDexFileFromZip(
     const DexZipArchive& zip_archive,
     const char* entry_name,
     const std::string& location,
     bool verify,
     bool verify_checksum,
     DexFileLoaderErrorCode* error_code,
     std::string* error_msg) const {
   CHECK(!location.empty());
   std::unique_ptr<DexZipEntry> zip_entry(zip_archive.Find(entry_name, error_msg));
   if (zip_entry == nullptr) {
     *error_code = DexFileLoaderErrorCode::kEntryNotFound;
     return nullptr;
   }
   if (zip_entry->GetUncompressedLength() == 0) {
     *error_msg = StringPrintf("Dex file '%s' has zero length", location.c_str());
     *error_code = DexFileLoaderErrorCode::kDexFileError;
     return nullptr;
   }

   std::vector<uint8_t> map(zip_entry->Extract(error_msg));
   if (map.size() == 0) {
     *error_msg = StringPrintf("Failed to extract '%s' from '%s': %s", entry_name, location.c_str(),
                               error_msg->c_str());
     *error_code = DexFileLoaderErrorCode::kExtractToMemoryError;
     return nullptr;
   }
   VerifyResult verify_result;
   std::unique_ptr<const DexFile> dex_file = OpenCommon(
       map.data(),
       map.size(),
       /*data_base=*/ nullptr,
       /*data_size=*/ 0u,
       location,
       zip_entry->GetCrc32(),
       /*oat_dex_file=*/ nullptr,
       verify,
       verify_checksum,
       error_msg,
       std::make_unique<VectorContainer>(std::move(map)),
       &verify_result);
   if (verify_result != VerifyResult::kVerifySucceeded) {
     if (verify_result == VerifyResult::kVerifyNotAttempted) {
       *error_code = DexFileLoaderErrorCode::kDexFileError;
     } else {
       *error_code = DexFileLoaderErrorCode::kVerifyError;
     }
     return nullptr;
   }
   *error_code = DexFileLoaderErrorCode::kNoError;
   return dex_file;
 }

 // Technically we do not have a limitation with respect to the number of dex files that can be in a
 // multidex APK. However, it's bad practice, as each dex file requires its own tables for symbols
 // (types, classes, methods, ...) and dex caches. So warn the user that we open a zip with what
 // seems an excessive number.
 static constexpr size_t kWarnOnManyDexFilesThreshold = 100;

 bool DexFileLoader::OpenAllDexFilesFromZip(
     const DexZipArchive& zip_archive,
     const std::string& location,
     bool verify,
     bool verify_checksum,
     DexFileLoaderErrorCode* error_code,
     std::string* error_msg,
     std::vector<std::unique_ptr<const DexFile>>* dex_files) const {
   DCHECK(dex_files != nullptr) << "DexFile::OpenFromZip: out-param is nullptr";
   std::unique_ptr<const DexFile> dex_file(OpenOneDexFileFromZip(zip_archive,
                                                                 kClassesDex,
                                                                 location,
                                                                 verify,
                                                                 verify_checksum,
                                                                 error_code,
                                                                 error_msg));
   if (*error_code != DexFileLoaderErrorCode::kNoError) {
     return false;
   } else {
     // Had at least classes.dex.
     dex_files->push_back(std::move(dex_file));

     // Now try some more.

     // We could try to avoid std::string allocations by working on a char array directly. As we
     // do not expect a lot of iterations, this seems too involved and brittle.

     for (size_t i = 1; ; ++i) {
       std::string name = GetMultiDexClassesDexName(i);
       std::string fake_location = GetMultiDexLocation(i, location.c_str());
       std::unique_ptr<const DexFile> next_dex_file(OpenOneDexFileFromZip(zip_archive,
                                                                          name.c_str(),
                                                                          fake_location,
                                                                          verify,
                                                                          verify_checksum,
                                                                          error_code,
                                                                          error_msg));
       if (next_dex_file.get() == nullptr) {
         if (*error_code != DexFileLoaderErrorCode::kEntryNotFound) {
           LOG(WARNING) << "Zip open failed: " << *error_msg;
         }
         break;
       } else {
         dex_files->push_back(std::move(next_dex_file));
       }

       if (i == kWarnOnManyDexFilesThreshold) {
         LOG(WARNING) << location << " has in excess of " << kWarnOnManyDexFilesThreshold
                      << " dex files. Please consider coalescing and shrinking the number to "
                         " avoid runtime overhead.";
       }

       if (i == std::numeric_limits<size_t>::max()) {
         LOG(ERROR) << "Overflow in number of dex files!";
         break;
       }
     }

     return true;
   }
 }
 }  // namespace art
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "dex_file_loader.h"

	#include "android-base/stringprintf.h"

	#include "base/stl_util.h"
	#include "compact_dex_file.h"
	#include "dex_file.h"
	#include "dex_file_verifier.h"
	#include "standard_dex_file.h"
	#include "ziparchive/zip_archive.h"

	namespace art {

	namespace {

	class VectorContainer : public DexFileContainer {
	public:
	explicit VectorContainer(std::vector<uint8_t>&& vector) : vector_(std::move(vector)) { }
	~VectorContainer() override { }

	int GetPermissions() override {
	return 0;
	}

	bool IsReadOnly() override {
	return true;
	}

	bool EnableWrite() override {
	return false;
	}

	bool DisableWrite() override {
	return false;
	}

	private:
	std::vector<uint8_t> vector_;
	DISALLOW_COPY_AND_ASSIGN(VectorContainer);
	};

	} // namespace

	using android::base::StringPrintf;

	class DexZipArchive;

	class DexZipEntry {
	public:
	// Extract this entry to memory.
	// Returns null on failure and sets error_msg.
	const std::vector<uint8_t> Extract(std::string* error_msg) {
	std::vector<uint8_t> map(GetUncompressedLength());
	if (map.size() == 0) {
	DCHECK(!error_msg->empty());
	return map;
	}
	const int32_t error = ExtractToMemory(handle_, zip_entry_, map.data(), map.size());
	if (error) {
	*error_msg = std::string(ErrorCodeString(error));
	}
	return map;
	}

	virtual ~DexZipEntry() {
	delete zip_entry_;
	}

	uint32_t GetUncompressedLength() {
	return zip_entry_->uncompressed_length;
	}

	uint32_t GetCrc32() {
	return zip_entry_->crc32;
	}

	private:
	DexZipEntry(ZipArchiveHandle handle,
	::ZipEntry* zip_entry,
	const std::string& entry_name)
	: handle_(handle), zip_entry_(zip_entry), entry_name_(entry_name) {}

	ZipArchiveHandle handle_;
	::ZipEntry* const zip_entry_;
	std::string const entry_name_;

	friend class DexZipArchive;
	DISALLOW_COPY_AND_ASSIGN(DexZipEntry);
	};

	class DexZipArchive {
	public:
	// return new DexZipArchive instance on success, null on error.
	static DexZipArchive* Open(const uint8_t* base, size_t size, std::string* error_msg) {
	ZipArchiveHandle handle;
	uint8_t* nonconst_base = const_cast<uint8_t*>(base);
	const int32_t error = OpenArchiveFromMemory(nonconst_base, size, "ZipArchiveMemory", &handle);
	if (error) {
	*error_msg = std::string(ErrorCodeString(error));
	CloseArchive(handle);
	return nullptr;
	}
	return new DexZipArchive(handle);
	}

	DexZipEntry* Find(const char* name, std::string* error_msg) const {
	DCHECK(name != nullptr);
	// Resist the urge to delete the space. <: is a bigraph sequence.
	std::unique_ptr< ::ZipEntry> zip_entry(new ::ZipEntry);
	const int32_t error = FindEntry(handle_, ZipString(name), zip_entry.get());
	if (error) {
	*error_msg = std::string(ErrorCodeString(error));
	return nullptr;
	}
	return new DexZipEntry(handle_, zip_entry.release(), name);
	}

	~DexZipArchive() {
	CloseArchive(handle_);
	}


	private:
	explicit DexZipArchive(ZipArchiveHandle handle) : handle_(handle) {}
	ZipArchiveHandle handle_;

	friend class DexZipEntry;
	DISALLOW_COPY_AND_ASSIGN(DexZipArchive);
	};

	static bool IsZipMagic(uint32_t magic) {
	return (('P' == ((magic >> 0) & 0xff)) &&
	('K' == ((magic >> 8) & 0xff)));
	}

	bool DexFileLoader::IsMagicValid(uint32_t magic) {
	return IsMagicValid(reinterpret_cast<uint8_t*>(&magic));
	}

	bool DexFileLoader::IsMagicValid(const uint8_t* magic) {
	return StandardDexFile::IsMagicValid(magic) \|\|
	CompactDexFile::IsMagicValid(magic);
	}

	bool DexFileLoader::IsVersionAndMagicValid(const uint8_t* magic) {
	if (StandardDexFile::IsMagicValid(magic)) {
	return StandardDexFile::IsVersionValid(magic);
	}
	if (CompactDexFile::IsMagicValid(magic)) {
	return CompactDexFile::IsVersionValid(magic);
	}
	return false;
	}

	bool DexFileLoader::IsMultiDexLocation(const char* location) {
	return strrchr(location, kMultiDexSeparator) != nullptr;
	}

	std::string DexFileLoader::GetMultiDexClassesDexName(size_t index) {
	return (index == 0) ? "classes.dex" : StringPrintf("classes%zu.dex", index + 1);
	}

	std::string DexFileLoader::GetMultiDexLocation(size_t index, const char* dex_location) {
	return (index == 0)
	? dex_location
	: StringPrintf("%s%cclasses%zu.dex", dex_location, kMultiDexSeparator, index + 1);
	}

	std::string DexFileLoader::GetDexCanonicalLocation(const char* dex_location) {
	CHECK_NE(dex_location, static_cast<const char*>(nullptr));
	std::string base_location = GetBaseLocation(dex_location);
	const char* suffix = dex_location + base_location.size();
	DCHECK(suffix[0] == 0 \|\| suffix[0] == kMultiDexSeparator);
	#ifdef _WIN32
	// Warning: No symbolic link processing here.
	PLOG(WARNING) << "realpath is unsupported on Windows.";
	#else
	// Warning: Bionic implementation of realpath() allocates > 12KB on the stack.
	// Do not run this code on a small stack, e.g. in signal handler.
	UniqueCPtr<const char[]> path(realpath(base_location.c_str(), nullptr));
	if (path != nullptr && path.get() != base_location) {
	return std::string(path.get()) + suffix;
	}
	#endif
	if (suffix[0] == 0) {
	return base_location;
	} else {
	return dex_location;
	}
	}

	// All of the implementations here should be independent of the runtime.
	// TODO: implement all the virtual methods.

	bool DexFileLoader::GetMultiDexChecksums(
	const char* filename ATTRIBUTE_UNUSED,
	std::vector<uint32_t>* checksums ATTRIBUTE_UNUSED,
	std::string* error_msg,
	int zip_fd ATTRIBUTE_UNUSED,
	bool* zip_file_only_contains_uncompress_dex ATTRIBUTE_UNUSED) const {
	*error_msg = "UNIMPLEMENTED";
	return false;
	}

	std::unique_ptr<const DexFile> DexFileLoader::Open(
	const uint8_t* base,
	size_t size,
	const std::string& location,
	uint32_t location_checksum,
	const OatDexFile* oat_dex_file,
	bool verify,
	bool verify_checksum,
	std::string* error_msg,
	std::unique_ptr<DexFileContainer> container) const {
	return OpenCommon(base,
	size,
	/data_base=/ nullptr,
	/data_size=/ 0,
	location,
	location_checksum,
	oat_dex_file,
	verify,
	verify_checksum,
	error_msg,
	std::move(container),
	/verify_result=/ nullptr);
	}

	std::unique_ptr<const DexFile> DexFileLoader::OpenWithDataSection(
	const uint8_t* base,
	size_t size,
	const uint8_t* data_base,
	size_t data_size,
	const std::string& location,
	uint32_t location_checksum,
	const OatDexFile* oat_dex_file,
	bool verify,
	bool verify_checksum,
	std::string* error_msg) const {
	return OpenCommon(base,
	size,
	data_base,
	data_size,
	location,
	location_checksum,
	oat_dex_file,
	verify,
	verify_checksum,
	error_msg,
	/container=/ nullptr,
	/verify_result=/ nullptr);
	}

	bool DexFileLoader::OpenAll(
	const uint8_t* base,
	size_t size,
	const std::string& location,
	bool verify,
	bool verify_checksum,
	DexFileLoaderErrorCode* error_code,
	std::string* error_msg,
	std::vector<std::unique_ptr<const DexFile>>* dex_files) const {
	DCHECK(dex_files != nullptr) << "DexFile::Open: out-param is nullptr";
	uint32_t magic = reinterpret_cast<const uint32_t>(base);
	if (IsZipMagic(magic)) {
	std::unique_ptr<DexZipArchive> zip_archive(DexZipArchive::Open(base, size, error_msg));
	if (zip_archive.get() == nullptr) {
	DCHECK(!error_msg->empty());
	return false;
	}
	return OpenAllDexFilesFromZip(*zip_archive.get(),
	location,
	verify,
	verify_checksum,
	error_code,
	error_msg,
	dex_files);
	}
	if (IsMagicValid(magic)) {
	const DexFile::Header* dex_header = reinterpret_cast<const DexFile::Header*>(base);
	std::unique_ptr<const DexFile> dex_file(Open(base,
	size,
	location,
	dex_header->checksum_,
	/oat_dex_file=/ nullptr,
	verify,
	verify_checksum,
	error_msg));
	if (dex_file.get() != nullptr) {
	dex_files->push_back(std::move(dex_file));
	return true;
	} else {
	return false;
	}
	}
	*error_msg = StringPrintf("Expected valid zip or dex file");
	return false;
	}

	std::unique_ptr<DexFile> DexFileLoader::OpenCommon(const uint8_t* base,
	size_t size,
	const uint8_t* data_base,
	size_t data_size,
	const std::string& location,
	uint32_t location_checksum,
	const OatDexFile* oat_dex_file,
	bool verify,
	bool verify_checksum,
	std::string* error_msg,
	std::unique_ptr<DexFileContainer> container,
	VerifyResult* verify_result) {
	if (verify_result != nullptr) {
	*verify_result = VerifyResult::kVerifyNotAttempted;
	}
	std::unique_ptr<DexFile> dex_file;
	if (size >= sizeof(StandardDexFile::Header) && StandardDexFile::IsMagicValid(base)) {
	if (data_size != 0) {
	CHECK_EQ(base, data_base) << "Unsupported for standard dex";
	}
	dex_file.reset(new StandardDexFile(base,
	size,
	location,
	location_checksum,
	oat_dex_file,
	std::move(container)));
	} else if (size >= sizeof(CompactDexFile::Header) && CompactDexFile::IsMagicValid(base)) {
	if (data_base == nullptr) {
	// TODO: Is there a clean way to support both an explicit data section and reading the one
	// from the header.
	CHECK_EQ(data_size, 0u);
	const CompactDexFile::Header* const header = CompactDexFile::Header::At(base);
	data_base = base + header->data_off_;
	data_size = header->data_size_;
	}
	dex_file.reset(new CompactDexFile(base,
	size,
	data_base,
	data_size,
	location,
	location_checksum,
	oat_dex_file,
	std::move(container)));
	// Disable verification for CompactDex input.
	verify = false;
	} else {
	*error_msg = "Invalid or truncated dex file";
	}
	if (dex_file == nullptr) {
	*error_msg = StringPrintf("Failed to open dex file '%s' from memory: %s", location.c_str(),
	error_msg->c_str());
	return nullptr;
	}
	if (!dex_file->Init(error_msg)) {
	dex_file.reset();
	return nullptr;
	}
	if (verify && !DexFileVerifier::Verify(dex_file.get(),
	dex_file->Begin(),
	dex_file->Size(),
	location.c_str(),
	verify_checksum,
	error_msg)) {
	if (verify_result != nullptr) {
	*verify_result = VerifyResult::kVerifyFailed;
	}
	return nullptr;
	}
	if (verify_result != nullptr) {
	*verify_result = VerifyResult::kVerifySucceeded;
	}
	return dex_file;
	}

	std::unique_ptr<const DexFile> DexFileLoader::OpenOneDexFileFromZip(
	const DexZipArchive& zip_archive,
	const char* entry_name,
	const std::string& location,
	bool verify,
	bool verify_checksum,
	DexFileLoaderErrorCode* error_code,
	std::string* error_msg) const {
	CHECK(!location.empty());
	std::unique_ptr<DexZipEntry> zip_entry(zip_archive.Find(entry_name, error_msg));
	if (zip_entry == nullptr) {
	*error_code = DexFileLoaderErrorCode::kEntryNotFound;
	return nullptr;
	}
	if (zip_entry->GetUncompressedLength() == 0) {
	*error_msg = StringPrintf("Dex file '%s' has zero length", location.c_str());
	*error_code = DexFileLoaderErrorCode::kDexFileError;
	return nullptr;
	}

	std::vector<uint8_t> map(zip_entry->Extract(error_msg));
	if (map.size() == 0) {
	*error_msg = StringPrintf("Failed to extract '%s' from '%s': %s", entry_name, location.c_str(),
	error_msg->c_str());
	*error_code = DexFileLoaderErrorCode::kExtractToMemoryError;
	return nullptr;
	}
	VerifyResult verify_result;
	std::unique_ptr<const DexFile> dex_file = OpenCommon(
	map.data(),
	map.size(),
	/data_base=/ nullptr,
	/data_size=/ 0u,
	location,
	zip_entry->GetCrc32(),
	/oat_dex_file=/ nullptr,
	verify,
	verify_checksum,
	error_msg,
	std::make_unique<VectorContainer>(std::move(map)),
	&verify_result);
	if (verify_result != VerifyResult::kVerifySucceeded) {
	if (verify_result == VerifyResult::kVerifyNotAttempted) {
	*error_code = DexFileLoaderErrorCode::kDexFileError;
	} else {
	*error_code = DexFileLoaderErrorCode::kVerifyError;
	}
	return nullptr;
	}
	*error_code = DexFileLoaderErrorCode::kNoError;
	return dex_file;
	}

	// Technically we do not have a limitation with respect to the number of dex files that can be in a
	// multidex APK. However, it's bad practice, as each dex file requires its own tables for symbols
	// (types, classes, methods, ...) and dex caches. So warn the user that we open a zip with what
	// seems an excessive number.
	static constexpr size_t kWarnOnManyDexFilesThreshold = 100;

	bool DexFileLoader::OpenAllDexFilesFromZip(
	const DexZipArchive& zip_archive,
	const std::string& location,
	bool verify,
	bool verify_checksum,
	DexFileLoaderErrorCode* error_code,
	std::string* error_msg,
	std::vector<std::unique_ptr<const DexFile>>* dex_files) const {
	DCHECK(dex_files != nullptr) << "DexFile::OpenFromZip: out-param is nullptr";
	std::unique_ptr<const DexFile> dex_file(OpenOneDexFileFromZip(zip_archive,
	kClassesDex,
	location,
	verify,
	verify_checksum,
	error_code,
	error_msg));
	if (*error_code != DexFileLoaderErrorCode::kNoError) {
	return false;
	} else {
	// Had at least classes.dex.
	dex_files->push_back(std::move(dex_file));

	// Now try some more.

	// We could try to avoid std::string allocations by working on a char array directly. As we
	// do not expect a lot of iterations, this seems too involved and brittle.

	for (size_t i = 1; ; ++i) {
	std::string name = GetMultiDexClassesDexName(i);
	std::string fake_location = GetMultiDexLocation(i, location.c_str());
	std::unique_ptr<const DexFile> next_dex_file(OpenOneDexFileFromZip(zip_archive,
	name.c_str(),
	fake_location,
	verify,
	verify_checksum,
	error_code,
	error_msg));
	if (next_dex_file.get() == nullptr) {
	if (*error_code != DexFileLoaderErrorCode::kEntryNotFound) {
	LOG(WARNING) << "Zip open failed: " << *error_msg;
	}
	break;
	} else {
	dex_files->push_back(std::move(next_dex_file));
	}

	if (i == kWarnOnManyDexFilesThreshold) {
	LOG(WARNING) << location << " has in excess of " << kWarnOnManyDexFilesThreshold
	<< " dex files. Please consider coalescing and shrinking the number to "
	" avoid runtime overhead.";
	}

	if (i == std::numeric_limits<size_t>::max()) {
	LOG(ERROR) << "Overflow in number of dex files!";
	break;
	}
	}

	return true;
	}
	}
	} // namespace art