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