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Brian Carlstrom6a47b9d2013-05-17 10:58:25 -07001/*
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_fixup.h"
18
Nicolas Geoffray50cfe742014-02-19 13:27:42 +000019#include <inttypes.h>
Ian Rogers700a4022014-05-19 16:49:03 -070020#include <memory>
Nicolas Geoffray50cfe742014-02-19 13:27:42 +000021
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070022#include "base/logging.h"
23#include "base/stringprintf.h"
24#include "elf_file.h"
25#include "elf_writer.h"
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070026
27namespace art {
28
29static const bool DEBUG_FIXUP = false;
30
31bool ElfFixup::Fixup(File* file, uintptr_t oat_data_begin) {
Ian Rogers8d31bbd2013-10-13 10:44:14 -070032 std::string error_msg;
Ian Rogers700a4022014-05-19 16:49:03 -070033 std::unique_ptr<ElfFile> elf_file(ElfFile::Open(file, true, false, &error_msg));
Ian Rogers8d31bbd2013-10-13 10:44:14 -070034 CHECK(elf_file.get() != nullptr) << error_msg;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070035
36 // Lookup "oatdata" symbol address.
Nicolas Geoffray50cfe742014-02-19 13:27:42 +000037 Elf32_Addr oatdata_address = ElfWriter::GetOatDataAddress(elf_file.get());
38 Elf32_Off base_address = oat_data_begin - oatdata_address;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070039
40 if (!FixupDynamic(*elf_file.get(), base_address)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070041 LOG(WARNING) << "Failed to fixup .dynamic in " << file->GetPath();
42 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070043 }
44 if (!FixupSectionHeaders(*elf_file.get(), base_address)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070045 LOG(WARNING) << "Failed to fixup section headers in " << file->GetPath();
46 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070047 }
48 if (!FixupProgramHeaders(*elf_file.get(), base_address)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070049 LOG(WARNING) << "Failed to fixup program headers in " << file->GetPath();
50 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070051 }
52 if (!FixupSymbols(*elf_file.get(), base_address, true)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070053 LOG(WARNING) << "Failed to fixup .dynsym in " << file->GetPath();
54 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070055 }
56 if (!FixupSymbols(*elf_file.get(), base_address, false)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070057 LOG(WARNING) << "Failed to fixup .symtab in " << file->GetPath();
58 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070059 }
60 if (!FixupRelocations(*elf_file.get(), base_address)) {
Yevgeny Roubane3ea8382014-08-08 16:29:38 +070061 LOG(WARNING) << "Failed to fixup .rel.dyn in " << file->GetPath();
62 return false;
63 }
64 if (!elf_file->FixupDebugSections(base_address)) {
65 LOG(WARNING) << "Failed to fixup debug sections in " << file->GetPath();
66 return false;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070067 }
68 return true;
69}
70
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070071
72bool ElfFixup::FixupDynamic(ElfFile& elf_file, uintptr_t base_address) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +000073 for (Elf32_Word i = 0; i < elf_file.GetDynamicNum(); i++) {
74 Elf32_Dyn& elf_dyn = elf_file.GetDynamic(i);
75 Elf32_Word d_tag = elf_dyn.d_tag;
Alex Light53cb16b2014-06-12 11:26:29 -070076 if (IsDynamicSectionPointer(d_tag, elf_file.GetHeader().e_machine)) {
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070077 uint32_t d_ptr = elf_dyn.d_un.d_ptr;
78 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -080079 LOG(INFO) << StringPrintf("In %s moving Elf32_Dyn[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070080 elf_file.GetFile().GetPath().c_str(), i,
81 d_ptr, d_ptr + base_address);
82 }
83 d_ptr += base_address;
84 elf_dyn.d_un.d_ptr = d_ptr;
85 }
86 }
87 return true;
88}
89
90bool ElfFixup::FixupSectionHeaders(ElfFile& elf_file, uintptr_t base_address) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +000091 for (Elf32_Word i = 0; i < elf_file.GetSectionHeaderNum(); i++) {
92 Elf32_Shdr& sh = elf_file.GetSectionHeader(i);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070093 // 0 implies that the section will not exist in the memory of the process
94 if (sh.sh_addr == 0) {
95 continue;
96 }
97 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -080098 LOG(INFO) << StringPrintf("In %s moving Elf32_Shdr[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -070099 elf_file.GetFile().GetPath().c_str(), i,
100 sh.sh_addr, sh.sh_addr + base_address);
101 }
102 sh.sh_addr += base_address;
103 }
104 return true;
105}
106
107bool ElfFixup::FixupProgramHeaders(ElfFile& elf_file, uintptr_t base_address) {
108 // TODO: ELFObjectFile doesn't have give to Elf32_Phdr, so we do that ourselves for now.
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000109 for (Elf32_Word i = 0; i < elf_file.GetProgramHeaderNum(); i++) {
110 Elf32_Phdr& ph = elf_file.GetProgramHeader(i);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700111 CHECK_EQ(ph.p_vaddr, ph.p_paddr) << elf_file.GetFile().GetPath() << " i=" << i;
112 CHECK((ph.p_align == 0) || (0 == ((ph.p_vaddr - ph.p_offset) & (ph.p_align - 1))))
113 << elf_file.GetFile().GetPath() << " i=" << i;
114 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -0800115 LOG(INFO) << StringPrintf("In %s moving Elf32_Phdr[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700116 elf_file.GetFile().GetPath().c_str(), i,
117 ph.p_vaddr, ph.p_vaddr + base_address);
118 }
119 ph.p_vaddr += base_address;
120 ph.p_paddr += base_address;
121 CHECK((ph.p_align == 0) || (0 == ((ph.p_vaddr - ph.p_offset) & (ph.p_align - 1))))
122 << elf_file.GetFile().GetPath() << " i=" << i;
123 }
124 return true;
125}
126
127bool ElfFixup::FixupSymbols(ElfFile& elf_file, uintptr_t base_address, bool dynamic) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000128 Elf32_Word section_type = dynamic ? SHT_DYNSYM : SHT_SYMTAB;
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700129 // TODO: Unfortunate ELFObjectFile has protected symbol access, so use ElfFile
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000130 Elf32_Shdr* symbol_section = elf_file.FindSectionByType(section_type);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700131 if (symbol_section == NULL) {
132 // file is missing optional .symtab
133 CHECK(!dynamic) << elf_file.GetFile().GetPath();
134 return true;
135 }
136 for (uint32_t i = 0; i < elf_file.GetSymbolNum(*symbol_section); i++) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000137 Elf32_Sym& symbol = elf_file.GetSymbol(section_type, i);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700138 if (symbol.st_value != 0) {
139 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -0800140 LOG(INFO) << StringPrintf("In %s moving Elf32_Sym[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700141 elf_file.GetFile().GetPath().c_str(), i,
142 symbol.st_value, symbol.st_value + base_address);
143 }
144 symbol.st_value += base_address;
145 }
146 }
147 return true;
148}
149
150bool ElfFixup::FixupRelocations(ElfFile& elf_file, uintptr_t base_address) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000151 for (Elf32_Word i = 0; i < elf_file.GetSectionHeaderNum(); i++) {
152 Elf32_Shdr& sh = elf_file.GetSectionHeader(i);
153 if (sh.sh_type == SHT_REL) {
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700154 for (uint32_t i = 0; i < elf_file.GetRelNum(sh); i++) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000155 Elf32_Rel& rel = elf_file.GetRel(sh, i);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700156 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -0800157 LOG(INFO) << StringPrintf("In %s moving Elf32_Rel[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700158 elf_file.GetFile().GetPath().c_str(), i,
159 rel.r_offset, rel.r_offset + base_address);
160 }
161 rel.r_offset += base_address;
162 }
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000163 } else if (sh.sh_type == SHT_RELA) {
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700164 for (uint32_t i = 0; i < elf_file.GetRelaNum(sh); i++) {
Nicolas Geoffray50cfe742014-02-19 13:27:42 +0000165 Elf32_Rela& rela = elf_file.GetRela(sh, i);
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700166 if (DEBUG_FIXUP) {
Ian Rogersef7d42f2014-01-06 12:55:46 -0800167 LOG(INFO) << StringPrintf("In %s moving Elf32_Rela[%d] from 0x%08x to 0x%08" PRIxPTR,
Brian Carlstrom6a47b9d2013-05-17 10:58:25 -0700168 elf_file.GetFile().GetPath().c_str(), i,
169 rela.r_offset, rela.r_offset + base_address);
170 }
171 rela.r_offset += base_address;
172 }
173 }
174 }
175 return true;
176}
177
178} // namespace art