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 
GetOatDataAddress(ElfFile * elf_file)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 
GetOatElfInformation(File * file,size_t * oat_loaded_size,size_t * oat_data_offset)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 
Fixup(File * file,uintptr_t oat_data_begin)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