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      1 /*
      2  * Copyright (C) 2012 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 "elf_writer.h"
     18 
     19 #include "base/unix_file/fd_file.h"
     20 #include "elf_file.h"
     21 
     22 namespace art {
     23 namespace linker {
     24 
     25 uintptr_t ElfWriter::GetOatDataAddress(ElfFile* elf_file) {
     26   uintptr_t oatdata_address = elf_file->FindSymbolAddress(SHT_DYNSYM,
     27                                                            "oatdata",
     28                                                            false);
     29   CHECK_NE(0U, oatdata_address);
     30   return oatdata_address;
     31 }
     32 
     33 void ElfWriter::GetOatElfInformation(File* file,
     34                                      size_t* oat_loaded_size,
     35                                      size_t* oat_data_offset) {
     36   std::string error_msg;
     37   std::unique_ptr<ElfFile> elf_file(ElfFile::Open(file,
     38                                                   false,
     39                                                   false,
     40                                                   /*low_4gb*/false,
     41                                                   &error_msg));
     42   CHECK(elf_file.get() != nullptr) << error_msg;
     43 
     44   bool success = elf_file->GetLoadedSize(oat_loaded_size, &error_msg);
     45   CHECK(success) << error_msg;
     46   CHECK_NE(0U, *oat_loaded_size);
     47   *oat_data_offset = GetOatDataAddress(elf_file.get());
     48   CHECK_NE(0U, *oat_data_offset);
     49 }
     50 
     51 bool ElfWriter::Fixup(File* file, uintptr_t oat_data_begin) {
     52   std::string error_msg;
     53   std::unique_ptr<ElfFile> elf_file(ElfFile::Open(file, true, false, /*low_4gb*/false, &error_msg));
     54   CHECK(elf_file.get() != nullptr) << error_msg;
     55 
     56   // Lookup "oatdata" symbol address.
     57   uintptr_t oatdata_address = ElfWriter::GetOatDataAddress(elf_file.get());
     58   uintptr_t base_address = oat_data_begin - oatdata_address;
     59 
     60   return elf_file->Fixup(base_address);
     61 }
     62 
     63 }  // namespace linker
     64 }  // namespace art
     65