libdexfile/external/dex_file_ext.cc - platform/art - Git at Google

 /*
  * Copyright (C) 2018 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 "art_api/dex_file_external.h"

 #include <inttypes.h>
 #include <stdint.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>

 #include <cerrno>
 #include <cstring>
 #include <map>
 #include <memory>
 #include <string>
 #include <utility>
 #include <vector>

 #include <android-base/logging.h>
 #include <android-base/macros.h>
 #include <android-base/mapped_file.h>
 #include <android-base/stringprintf.h>

 #include <dex/class_accessor-inl.h>
 #include <dex/code_item_accessors-inl.h>
 #include <dex/dex_file-inl.h>
 #include <dex/dex_file_loader.h>

 namespace art {
 namespace {

 struct MethodCacheEntry {
   int32_t offset;  // Offset relative to the start of the dex file header.
   int32_t len;
   int32_t index;  // Method index.
 };

 class MappedFileContainer : public DexFileContainer {
  public:
   explicit MappedFileContainer(std::unique_ptr<android::base::MappedFile>&& map)
       : map_(std::move(map)) {}
   ~MappedFileContainer() override {}
   int GetPermissions() override { return 0; }
   bool IsReadOnly() override { return true; }
   bool EnableWrite() override { return false; }
   bool DisableWrite() override { return false; }

  private:
   std::unique_ptr<android::base::MappedFile> map_;
   DISALLOW_COPY_AND_ASSIGN(MappedFileContainer);
 };

 }  // namespace
 }  // namespace art

 extern "C" {

 struct ExtDexFileString {
   const std::string str_;
 };

 static const ExtDexFileString empty_string{""};

 const ExtDexFileString* ExtDexFileMakeString(const char* str, size_t size) {
   if (size == 0) {
     return &empty_string;
   }
   return new ExtDexFileString{std::string(str, size)};
 }

 const char* ExtDexFileGetString(const ExtDexFileString* ext_string, /*out*/ size_t* size) {
   DCHECK(ext_string != nullptr);
   *size = ext_string->str_.size();
   return ext_string->str_.data();
 }

 void ExtDexFileFreeString(const ExtDexFileString* ext_string) {
   DCHECK(ext_string != nullptr);
   if (ext_string != &empty_string) {
     delete (ext_string);
   }
 }

 // Wraps DexFile to add the caching needed by the external interface. This is
 // what gets passed over as ExtDexFile*.
 struct ExtDexFile {
  private:
   // Method cache for GetMethodInfoForOffset. This is populated as we iterate
   // sequentially through the class defs. MethodCacheEntry.name is only set for
   // methods returned by GetMethodInfoForOffset.
   std::map<int32_t, art::MethodCacheEntry> method_cache_;

   // Index of first class def for which method_cache_ isn't complete.
   uint32_t class_def_index_ = 0;

  public:
   std::unique_ptr<const art::DexFile> dex_file_;
   explicit ExtDexFile(std::unique_ptr<const art::DexFile>&& dex_file)
       : dex_file_(std::move(dex_file)) {}

   art::MethodCacheEntry* GetMethodCacheEntryForOffset(int64_t dex_offset) {
     // First look in the method cache.
     auto it = method_cache_.upper_bound(dex_offset);
     if (it != method_cache_.end() && dex_offset >= it->second.offset) {
       return &it->second;
     }

     for (; class_def_index_ < dex_file_->NumClassDefs(); class_def_index_++) {
       art::ClassAccessor accessor(*dex_file_, class_def_index_);

       for (const art::ClassAccessor::Method& method : accessor.GetMethods()) {
         art::CodeItemInstructionAccessor code = method.GetInstructions();
         if (!code.HasCodeItem()) {
           continue;
         }

         int32_t offset = reinterpret_cast<const uint8_t*>(code.Insns()) - dex_file_->Begin();
         int32_t len = code.InsnsSizeInBytes();
         int32_t index = method.GetIndex();
         auto res = method_cache_.emplace(offset + len, art::MethodCacheEntry{offset, len, index});
         if (offset <= dex_offset && dex_offset < offset + len) {
           return &res.first->second;
         }
       }
     }

     return nullptr;
   }
 };

 int ExtDexFileOpenFromMemory(const void* addr,
                              /*inout*/ size_t* size,
                              const char* location,
                              /*out*/ const ExtDexFileString** ext_error_msg,
                              /*out*/ ExtDexFile** ext_dex_file) {
   if (*size < sizeof(art::DexFile::Header)) {
     *size = sizeof(art::DexFile::Header);
     *ext_error_msg = nullptr;
     return false;
   }

   const art::DexFile::Header* header = reinterpret_cast<const art::DexFile::Header*>(addr);
   uint32_t file_size = header->file_size_;
   if (art::CompactDexFile::IsMagicValid(header->magic_)) {
     // Compact dex files store the data section separately so that it can be shared.
     // Therefore we need to extend the read memory range to include it.
     // TODO: This might be wasteful as we might read data in between as well.
     //       In practice, this should be fine, as such sharing only happens on disk.
     uint32_t computed_file_size;
     if (__builtin_add_overflow(header->data_off_, header->data_size_, &computed_file_size)) {
       *ext_error_msg = new ExtDexFileString{
           android::base::StringPrintf("Corrupt CompactDexFile header in '%s'", location)};
       return false;
     }
     if (computed_file_size > file_size) {
       file_size = computed_file_size;
     }
   } else if (!art::StandardDexFile::IsMagicValid(header->magic_)) {
     *ext_error_msg = new ExtDexFileString{
         android::base::StringPrintf("Unrecognized dex file header in '%s'", location)};
     return false;
   }

   if (*size < file_size) {
     *size = file_size;
     *ext_error_msg = nullptr;
     return false;
   }

   std::string loc_str(location);
   art::DexFileLoader loader;
   std::string error_msg;
   std::unique_ptr<const art::DexFile> dex_file = loader.Open(static_cast<const uint8_t*>(addr),
                                                              *size,
                                                              loc_str,
                                                              header->checksum_,
                                                              /*oat_dex_file=*/nullptr,
                                                              /*verify=*/false,
                                                              /*verify_checksum=*/false,
                                                              &error_msg);
   if (dex_file == nullptr) {
     *ext_error_msg = new ExtDexFileString{std::move(error_msg)};
     return false;
   }

   *ext_dex_file = new ExtDexFile(std::move(dex_file));
   return true;
 }

 int ExtDexFileOpenFromFd(int fd,
                          off_t offset,
                          const char* location,
                          /*out*/ const ExtDexFileString** ext_error_msg,
                          /*out*/ ExtDexFile** ext_dex_file) {
   size_t length;
   {
     struct stat sbuf;
     std::memset(&sbuf, 0, sizeof(sbuf));
     if (fstat(fd, &sbuf) == -1) {
       *ext_error_msg = new ExtDexFileString{
           android::base::StringPrintf("fstat '%s' failed: %s", location, std::strerror(errno))};
       return false;
     }
     if (S_ISDIR(sbuf.st_mode)) {
       *ext_error_msg = new ExtDexFileString{
           android::base::StringPrintf("Attempt to mmap directory '%s'", location)};
       return false;
     }
     length = sbuf.st_size;
   }

   if (length < offset + sizeof(art::DexFile::Header)) {
     *ext_error_msg = new ExtDexFileString{android::base::StringPrintf(
         "Offset %" PRId64 " too large for '%s' of size %zu",
         int64_t{offset},
         location,
         length)};
     return false;
   }

   // Cannot use MemMap in libartbase here, because it pulls in dlopen which we
   // can't have when being compiled statically.
   std::unique_ptr<android::base::MappedFile> map =
       android::base::MappedFile::FromFd(fd, offset, length, PROT_READ);
   if (map == nullptr) {
     *ext_error_msg = new ExtDexFileString{
         android::base::StringPrintf("mmap '%s' failed: %s", location, std::strerror(errno))};
     return false;
   }

   const art::DexFile::Header* header = reinterpret_cast<const art::DexFile::Header*>(map->data());
   uint32_t file_size;
   if (__builtin_add_overflow(offset, header->file_size_, &file_size)) {
     *ext_error_msg =
         new ExtDexFileString{android::base::StringPrintf("Corrupt header in '%s'", location)};
     return false;
   }
   if (length < file_size) {
     *ext_error_msg = new ExtDexFileString{
         android::base::StringPrintf("Dex file '%s' too short: expected %" PRIu32 ", got %" PRIu64,
                                     location,
                                     file_size,
                                     uint64_t{length})};
     return false;
   }

   void* addr = map->data();
   size_t size = map->size();
   auto container = std::make_unique<art::MappedFileContainer>(std::move(map));

   std::string loc_str(location);
   std::string error_msg;
   art::DexFileLoader loader;
   std::unique_ptr<const art::DexFile> dex_file = loader.Open(reinterpret_cast<const uint8_t*>(addr),
                                                              size,
                                                              loc_str,
                                                              header->checksum_,
                                                              /*oat_dex_file=*/nullptr,
                                                              /*verify=*/false,
                                                              /*verify_checksum=*/false,
                                                              &error_msg,
                                                              std::move(container));
   if (dex_file == nullptr) {
     *ext_error_msg = new ExtDexFileString{std::move(error_msg)};
     return false;
   }
   *ext_dex_file = new ExtDexFile(std::move(dex_file));
   return true;
 }

 int ExtDexFileGetMethodInfoForOffset(ExtDexFile* ext_dex_file,
                                      int64_t dex_offset,
                                      int with_signature,
                                      /*out*/ ExtDexFileMethodInfo* method_info) {
   if (!ext_dex_file->dex_file_->IsInDataSection(ext_dex_file->dex_file_->Begin() + dex_offset)) {
     return false;  // The DEX offset is not within the bytecode of this dex file.
   }

   if (ext_dex_file->dex_file_->IsCompactDexFile()) {
     // The data section of compact dex files might be shared.
     // Check the subrange unique to this compact dex.
     const art::CompactDexFile::Header& cdex_header =
         ext_dex_file->dex_file_->AsCompactDexFile()->GetHeader();
     uint32_t begin = cdex_header.data_off_ + cdex_header.OwnedDataBegin();
     uint32_t end = cdex_header.data_off_ + cdex_header.OwnedDataEnd();
     if (dex_offset < begin || dex_offset >= end) {
       return false;  // The DEX offset is not within the bytecode of this dex file.
     }
   }

   art::MethodCacheEntry* entry = ext_dex_file->GetMethodCacheEntryForOffset(dex_offset);
   if (entry != nullptr) {
     method_info->offset = entry->offset;
     method_info->len = entry->len;
     method_info->name =
         new ExtDexFileString{ext_dex_file->dex_file_->PrettyMethod(entry->index, with_signature)};
     return true;
   }

   return false;
 }

 void ExtDexFileGetAllMethodInfos(ExtDexFile* ext_dex_file,
                                  int with_signature,
                                  ExtDexFileMethodInfoCallback* method_info_cb,
                                  void* user_data) {
   for (art::ClassAccessor accessor : ext_dex_file->dex_file_->GetClasses()) {
     for (const art::ClassAccessor::Method& method : accessor.GetMethods()) {
       art::CodeItemInstructionAccessor code = method.GetInstructions();
       if (!code.HasCodeItem()) {
         continue;
       }

       ExtDexFileMethodInfo method_info;
       method_info.offset = static_cast<int32_t>(reinterpret_cast<const uint8_t*>(code.Insns()) -
                                                 ext_dex_file->dex_file_->Begin());
       method_info.len = code.InsnsSizeInBytes();
       method_info.name = new ExtDexFileString{
           ext_dex_file->dex_file_->PrettyMethod(method.GetIndex(), with_signature)};
       method_info_cb(&method_info, user_data);
     }
   }
 }

 void ExtDexFileFree(ExtDexFile* ext_dex_file) { delete (ext_dex_file); }

 }  // extern "C"
	/*
	* Copyright (C) 2018 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 "art_api/dex_file_external.h"

	#include <inttypes.h>
	#include <stdint.h>
	#include <sys/mman.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>

	#include <cerrno>
	#include <cstring>
	#include <map>
	#include <memory>
	#include <string>
	#include <utility>
	#include <vector>

	#include <android-base/logging.h>
	#include <android-base/macros.h>
	#include <android-base/mapped_file.h>
	#include <android-base/stringprintf.h>

	#include <dex/class_accessor-inl.h>
	#include <dex/code_item_accessors-inl.h>
	#include <dex/dex_file-inl.h>
	#include <dex/dex_file_loader.h>

	namespace art {
	namespace {

	struct MethodCacheEntry {
	int32_t offset; // Offset relative to the start of the dex file header.
	int32_t len;
	int32_t index; // Method index.
	};

	class MappedFileContainer : public DexFileContainer {
	public:
	explicit MappedFileContainer(std::unique_ptr<android::base::MappedFile>&& map)
	: map_(std::move(map)) {}
	~MappedFileContainer() override {}
	int GetPermissions() override { return 0; }
	bool IsReadOnly() override { return true; }
	bool EnableWrite() override { return false; }
	bool DisableWrite() override { return false; }

	private:
	std::unique_ptr<android::base::MappedFile> map_;
	DISALLOW_COPY_AND_ASSIGN(MappedFileContainer);
	};

	} // namespace
	} // namespace art

	extern "C" {

	struct ExtDexFileString {
	const std::string str_;
	};

	static const ExtDexFileString empty_string{""};

	const ExtDexFileString* ExtDexFileMakeString(const char* str, size_t size) {
	if (size == 0) {
	return &empty_string;
	}
	return new ExtDexFileString{std::string(str, size)};
	}

	const char* ExtDexFileGetString(const ExtDexFileString* ext_string, /out/ size_t* size) {
	DCHECK(ext_string != nullptr);
	*size = ext_string->str_.size();
	return ext_string->str_.data();
	}

	void ExtDexFileFreeString(const ExtDexFileString* ext_string) {
	DCHECK(ext_string != nullptr);
	if (ext_string != &empty_string) {
	delete (ext_string);
	}
	}

	// Wraps DexFile to add the caching needed by the external interface. This is
	// what gets passed over as ExtDexFile*.
	struct ExtDexFile {
	private:
	// Method cache for GetMethodInfoForOffset. This is populated as we iterate
	// sequentially through the class defs. MethodCacheEntry.name is only set for
	// methods returned by GetMethodInfoForOffset.
	std::map<int32_t, art::MethodCacheEntry> method_cache_;

	// Index of first class def for which method_cache_ isn't complete.
	uint32_t class_def_index_ = 0;

	public:
	std::unique_ptr<const art::DexFile> dex_file_;
	explicit ExtDexFile(std::unique_ptr<const art::DexFile>&& dex_file)
	: dex_file_(std::move(dex_file)) {}

	art::MethodCacheEntry* GetMethodCacheEntryForOffset(int64_t dex_offset) {
	// First look in the method cache.
	auto it = method_cache_.upper_bound(dex_offset);
	if (it != method_cache_.end() && dex_offset >= it->second.offset) {
	return &it->second;
	}

	for (; class_def_index_ < dex_file_->NumClassDefs(); class_def_index_++) {
	art::ClassAccessor accessor(*dex_file_, class_def_index_);

	for (const art::ClassAccessor::Method& method : accessor.GetMethods()) {
	art::CodeItemInstructionAccessor code = method.GetInstructions();
	if (!code.HasCodeItem()) {
	continue;
	}

	int32_t offset = reinterpret_cast<const uint8_t*>(code.Insns()) - dex_file_->Begin();
	int32_t len = code.InsnsSizeInBytes();
	int32_t index = method.GetIndex();
	auto res = method_cache_.emplace(offset + len, art::MethodCacheEntry{offset, len, index});
	if (offset <= dex_offset && dex_offset < offset + len) {
	return &res.first->second;
	}
	}
	}

	return nullptr;
	}
	};

	int ExtDexFileOpenFromMemory(const void* addr,
	/inout/ size_t* size,
	const char* location,
	/out/ const ExtDexFileString** ext_error_msg,
	/out/ ExtDexFile** ext_dex_file) {
	if (*size < sizeof(art::DexFile::Header)) {
	*size = sizeof(art::DexFile::Header);
	*ext_error_msg = nullptr;
	return false;
	}

	const art::DexFile::Header* header = reinterpret_cast<const art::DexFile::Header*>(addr);
	uint32_t file_size = header->file_size_;
	if (art::CompactDexFile::IsMagicValid(header->magic_)) {
	// Compact dex files store the data section separately so that it can be shared.
	// Therefore we need to extend the read memory range to include it.
	// TODO: This might be wasteful as we might read data in between as well.
	// In practice, this should be fine, as such sharing only happens on disk.
	uint32_t computed_file_size;
	if (__builtin_add_overflow(header->data_off_, header->data_size_, &computed_file_size)) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("Corrupt CompactDexFile header in '%s'", location)};
	return false;
	}
	if (computed_file_size > file_size) {
	file_size = computed_file_size;
	}
	} else if (!art::StandardDexFile::IsMagicValid(header->magic_)) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("Unrecognized dex file header in '%s'", location)};
	return false;
	}

	if (*size < file_size) {
	*size = file_size;
	*ext_error_msg = nullptr;
	return false;
	}

	std::string loc_str(location);
	art::DexFileLoader loader;
	std::string error_msg;
	std::unique_ptr<const art::DexFile> dex_file = loader.Open(static_cast<const uint8_t*>(addr),
	*size,
	loc_str,
	header->checksum_,
	/oat_dex_file=/nullptr,
	/verify=/false,
	/verify_checksum=/false,
	&error_msg);
	if (dex_file == nullptr) {
	*ext_error_msg = new ExtDexFileString{std::move(error_msg)};
	return false;
	}

	*ext_dex_file = new ExtDexFile(std::move(dex_file));
	return true;
	}

	int ExtDexFileOpenFromFd(int fd,
	off_t offset,
	const char* location,
	/out/ const ExtDexFileString** ext_error_msg,
	/out/ ExtDexFile** ext_dex_file) {
	size_t length;
	{
	struct stat sbuf;
	std::memset(&sbuf, 0, sizeof(sbuf));
	if (fstat(fd, &sbuf) == -1) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("fstat '%s' failed: %s", location, std::strerror(errno))};
	return false;
	}
	if (S_ISDIR(sbuf.st_mode)) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("Attempt to mmap directory '%s'", location)};
	return false;
	}
	length = sbuf.st_size;
	}

	if (length < offset + sizeof(art::DexFile::Header)) {
	*ext_error_msg = new ExtDexFileString{android::base::StringPrintf(
	"Offset %" PRId64 " too large for '%s' of size %zu",
	int64_t{offset},
	location,
	length)};
	return false;
	}

	// Cannot use MemMap in libartbase here, because it pulls in dlopen which we
	// can't have when being compiled statically.
	std::unique_ptr<android::base::MappedFile> map =
	android::base::MappedFile::FromFd(fd, offset, length, PROT_READ);
	if (map == nullptr) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("mmap '%s' failed: %s", location, std::strerror(errno))};
	return false;
	}

	const art::DexFile::Header* header = reinterpret_cast<const art::DexFile::Header*>(map->data());
	uint32_t file_size;
	if (__builtin_add_overflow(offset, header->file_size_, &file_size)) {
	*ext_error_msg =
	new ExtDexFileString{android::base::StringPrintf("Corrupt header in '%s'", location)};
	return false;
	}
	if (length < file_size) {
	*ext_error_msg = new ExtDexFileString{
	android::base::StringPrintf("Dex file '%s' too short: expected %" PRIu32 ", got %" PRIu64,
	location,
	file_size,
	uint64_t{length})};
	return false;
	}

	void* addr = map->data();
	size_t size = map->size();
	auto container = std::make_unique<art::MappedFileContainer>(std::move(map));

	std::string loc_str(location);
	std::string error_msg;
	art::DexFileLoader loader;
	std::unique_ptr<const art::DexFile> dex_file = loader.Open(reinterpret_cast<const uint8_t*>(addr),
	size,
	loc_str,
	header->checksum_,
	/oat_dex_file=/nullptr,
	/verify=/false,
	/verify_checksum=/false,
	&error_msg,
	std::move(container));
	if (dex_file == nullptr) {
	*ext_error_msg = new ExtDexFileString{std::move(error_msg)};
	return false;
	}
	*ext_dex_file = new ExtDexFile(std::move(dex_file));
	return true;
	}

	int ExtDexFileGetMethodInfoForOffset(ExtDexFile* ext_dex_file,
	int64_t dex_offset,
	int with_signature,
	/out/ ExtDexFileMethodInfo* method_info) {
	if (!ext_dex_file->dex_file_->IsInDataSection(ext_dex_file->dex_file_->Begin() + dex_offset)) {
	return false; // The DEX offset is not within the bytecode of this dex file.
	}

	if (ext_dex_file->dex_file_->IsCompactDexFile()) {
	// The data section of compact dex files might be shared.
	// Check the subrange unique to this compact dex.
	const art::CompactDexFile::Header& cdex_header =
	ext_dex_file->dex_file_->AsCompactDexFile()->GetHeader();
	uint32_t begin = cdex_header.data_off_ + cdex_header.OwnedDataBegin();
	uint32_t end = cdex_header.data_off_ + cdex_header.OwnedDataEnd();
	if (dex_offset < begin \|\| dex_offset >= end) {
	return false; // The DEX offset is not within the bytecode of this dex file.
	}
	}

	art::MethodCacheEntry* entry = ext_dex_file->GetMethodCacheEntryForOffset(dex_offset);
	if (entry != nullptr) {
	method_info->offset = entry->offset;
	method_info->len = entry->len;
	method_info->name =
	new ExtDexFileString{ext_dex_file->dex_file_->PrettyMethod(entry->index, with_signature)};
	return true;
	}

	return false;
	}

	void ExtDexFileGetAllMethodInfos(ExtDexFile* ext_dex_file,
	int with_signature,
	ExtDexFileMethodInfoCallback* method_info_cb,
	void* user_data) {
	for (art::ClassAccessor accessor : ext_dex_file->dex_file_->GetClasses()) {
	for (const art::ClassAccessor::Method& method : accessor.GetMethods()) {
	art::CodeItemInstructionAccessor code = method.GetInstructions();
	if (!code.HasCodeItem()) {
	continue;
	}

	ExtDexFileMethodInfo method_info;
	method_info.offset = static_cast<int32_t>(reinterpret_cast<const uint8_t*>(code.Insns()) -
	ext_dex_file->dex_file_->Begin());
	method_info.len = code.InsnsSizeInBytes();
	method_info.name = new ExtDexFileString{
	ext_dex_file->dex_file_->PrettyMethod(method.GetIndex(), with_signature)};
	method_info_cb(&method_info, user_data);
	}
	}
	}

	void ExtDexFileFree(ExtDexFile* ext_dex_file) { delete (ext_dex_file); }

	} // extern "C"