1 /*
2 * Copyright (C) 2016 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 "vdex_file.h"
18
19 #include <sys/mman.h> // For the PROT_* and MAP_* constants.
20
21 #include <memory>
22
23 #include "base/logging.h"
24 #include "base/stl_util.h"
25 #include "base/unix_file/fd_file.h"
26 #include "dex_file.h"
27 #include "dex_to_dex_decompiler.h"
28
29 namespace art {
30
31 constexpr uint8_t VdexFile::Header::kVdexInvalidMagic[4];
32 constexpr uint8_t VdexFile::Header::kVdexMagic[4];
33 constexpr uint8_t VdexFile::Header::kVdexVersion[4];
34
IsMagicValid() const35 bool VdexFile::Header::IsMagicValid() const {
36 return (memcmp(magic_, kVdexMagic, sizeof(kVdexMagic)) == 0);
37 }
38
IsVersionValid() const39 bool VdexFile::Header::IsVersionValid() const {
40 return (memcmp(version_, kVdexVersion, sizeof(kVdexVersion)) == 0);
41 }
42
Header(uint32_t number_of_dex_files,uint32_t dex_size,uint32_t verifier_deps_size,uint32_t quickening_info_size)43 VdexFile::Header::Header(uint32_t number_of_dex_files,
44 uint32_t dex_size,
45 uint32_t verifier_deps_size,
46 uint32_t quickening_info_size)
47 : number_of_dex_files_(number_of_dex_files),
48 dex_size_(dex_size),
49 verifier_deps_size_(verifier_deps_size),
50 quickening_info_size_(quickening_info_size) {
51 memcpy(magic_, kVdexMagic, sizeof(kVdexMagic));
52 memcpy(version_, kVdexVersion, sizeof(kVdexVersion));
53 DCHECK(IsMagicValid());
54 DCHECK(IsVersionValid());
55 }
56
Open(const std::string & vdex_filename,bool writable,bool low_4gb,bool unquicken,std::string * error_msg)57 std::unique_ptr<VdexFile> VdexFile::Open(const std::string& vdex_filename,
58 bool writable,
59 bool low_4gb,
60 bool unquicken,
61 std::string* error_msg) {
62 if (!OS::FileExists(vdex_filename.c_str())) {
63 *error_msg = "File " + vdex_filename + " does not exist.";
64 return nullptr;
65 }
66
67 std::unique_ptr<File> vdex_file;
68 if (writable) {
69 vdex_file.reset(OS::OpenFileReadWrite(vdex_filename.c_str()));
70 } else {
71 vdex_file.reset(OS::OpenFileForReading(vdex_filename.c_str()));
72 }
73 if (vdex_file == nullptr) {
74 *error_msg = "Could not open file " + vdex_filename +
75 (writable ? " for read/write" : "for reading");
76 return nullptr;
77 }
78
79 int64_t vdex_length = vdex_file->GetLength();
80 if (vdex_length == -1) {
81 *error_msg = "Could not read the length of file " + vdex_filename;
82 return nullptr;
83 }
84
85 return Open(vdex_file->Fd(), vdex_length, vdex_filename, writable, low_4gb, unquicken, error_msg);
86 }
87
Open(int file_fd,size_t vdex_length,const std::string & vdex_filename,bool writable,bool low_4gb,bool unquicken,std::string * error_msg)88 std::unique_ptr<VdexFile> VdexFile::Open(int file_fd,
89 size_t vdex_length,
90 const std::string& vdex_filename,
91 bool writable,
92 bool low_4gb,
93 bool unquicken,
94 std::string* error_msg) {
95 std::unique_ptr<MemMap> mmap(MemMap::MapFile(
96 vdex_length,
97 (writable || unquicken) ? PROT_READ | PROT_WRITE : PROT_READ,
98 unquicken ? MAP_PRIVATE : MAP_SHARED,
99 file_fd,
100 0 /* start offset */,
101 low_4gb,
102 vdex_filename.c_str(),
103 error_msg));
104 if (mmap == nullptr) {
105 *error_msg = "Failed to mmap file " + vdex_filename + " : " + *error_msg;
106 return nullptr;
107 }
108
109 std::unique_ptr<VdexFile> vdex(new VdexFile(mmap.release()));
110 if (!vdex->IsValid()) {
111 *error_msg = "Vdex file is not valid";
112 return nullptr;
113 }
114
115 if (unquicken) {
116 std::vector<std::unique_ptr<const DexFile>> unique_ptr_dex_files;
117 if (!vdex->OpenAllDexFiles(&unique_ptr_dex_files, error_msg)) {
118 return nullptr;
119 }
120 Unquicken(MakeNonOwningPointerVector(unique_ptr_dex_files), vdex->GetQuickeningInfo());
121 // Update the quickening info size to pretend there isn't any.
122 reinterpret_cast<Header*>(vdex->mmap_->Begin())->quickening_info_size_ = 0;
123 }
124
125 *error_msg = "Success";
126 return vdex;
127 }
128
GetNextDexFileData(const uint8_t * cursor) const129 const uint8_t* VdexFile::GetNextDexFileData(const uint8_t* cursor) const {
130 DCHECK(cursor == nullptr || (cursor > Begin() && cursor <= End()));
131 if (cursor == nullptr) {
132 // Beginning of the iteration, return the first dex file if there is one.
133 return HasDexSection() ? DexBegin() : nullptr;
134 } else {
135 // Fetch the next dex file. Return null if there is none.
136 const uint8_t* data = cursor + reinterpret_cast<const DexFile::Header*>(cursor)->file_size_;
137 return (data == DexEnd()) ? nullptr : data;
138 }
139 }
140
OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>> * dex_files,std::string * error_msg)141 bool VdexFile::OpenAllDexFiles(std::vector<std::unique_ptr<const DexFile>>* dex_files,
142 std::string* error_msg) {
143 size_t i = 0;
144 for (const uint8_t* dex_file_start = GetNextDexFileData(nullptr);
145 dex_file_start != nullptr;
146 dex_file_start = GetNextDexFileData(dex_file_start), ++i) {
147 size_t size = reinterpret_cast<const DexFile::Header*>(dex_file_start)->file_size_;
148 // TODO: Supply the location information for a vdex file.
149 static constexpr char kVdexLocation[] = "";
150 std::string location = DexFile::GetMultiDexLocation(i, kVdexLocation);
151 std::unique_ptr<const DexFile> dex(DexFile::Open(dex_file_start,
152 size,
153 location,
154 GetLocationChecksum(i),
155 nullptr /*oat_dex_file*/,
156 false /*verify*/,
157 false /*verify_checksum*/,
158 error_msg));
159 if (dex == nullptr) {
160 return false;
161 }
162 dex_files->push_back(std::move(dex));
163 }
164 return true;
165 }
166
Unquicken(const std::vector<const DexFile * > & dex_files,const ArrayRef<const uint8_t> & quickening_info)167 void VdexFile::Unquicken(const std::vector<const DexFile*>& dex_files,
168 const ArrayRef<const uint8_t>& quickening_info) {
169 if (quickening_info.size() == 0) {
170 // If there is no quickening info, we bail early, as the code below expects at
171 // least the size of quickening data for each method that has a code item.
172 return;
173 }
174 const uint8_t* quickening_info_ptr = quickening_info.data();
175 const uint8_t* const quickening_info_end = quickening_info.data() + quickening_info.size();
176 for (const DexFile* dex_file : dex_files) {
177 for (uint32_t i = 0; i < dex_file->NumClassDefs(); ++i) {
178 const DexFile::ClassDef& class_def = dex_file->GetClassDef(i);
179 const uint8_t* class_data = dex_file->GetClassData(class_def);
180 if (class_data == nullptr) {
181 continue;
182 }
183 ClassDataItemIterator it(*dex_file, class_data);
184 // Skip fields
185 while (it.HasNextStaticField()) {
186 it.Next();
187 }
188 while (it.HasNextInstanceField()) {
189 it.Next();
190 }
191
192 while (it.HasNextDirectMethod()) {
193 const DexFile::CodeItem* code_item = it.GetMethodCodeItem();
194 if (code_item != nullptr) {
195 uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
196 quickening_info_ptr += sizeof(uint32_t);
197 optimizer::ArtDecompileDEX(*code_item,
198 ArrayRef<const uint8_t>(quickening_info_ptr, quickening_size),
199 /* decompile_return_instruction */ false);
200 quickening_info_ptr += quickening_size;
201 }
202 it.Next();
203 }
204
205 while (it.HasNextVirtualMethod()) {
206 const DexFile::CodeItem* code_item = it.GetMethodCodeItem();
207 if (code_item != nullptr) {
208 uint32_t quickening_size = *reinterpret_cast<const uint32_t*>(quickening_info_ptr);
209 quickening_info_ptr += sizeof(uint32_t);
210 optimizer::ArtDecompileDEX(*code_item,
211 ArrayRef<const uint8_t>(quickening_info_ptr, quickening_size),
212 /* decompile_return_instruction */ false);
213 quickening_info_ptr += quickening_size;
214 }
215 it.Next();
216 }
217 DCHECK(!it.HasNext());
218 }
219 }
220 if (quickening_info_ptr != quickening_info_end) {
221 LOG(FATAL) << "Failed to use all quickening info";
222 }
223 }
224
225 } // namespace art
226