Martin Stjernholm | b3d2e83 | 2018-11-15 18:09:35 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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 | #ifndef ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_EXT_DEX_FILE_H_ |
| 18 | #define ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_EXT_DEX_FILE_H_ |
| 19 | |
| 20 | // Dex file external API |
| 21 | |
| 22 | #include <sys/types.h> |
| 23 | |
| 24 | #include <cstring> |
| 25 | #include <memory> |
| 26 | #include <string> |
| 27 | #include <string_view> |
| 28 | #include <vector> |
| 29 | |
| 30 | #include <android-base/macros.h> |
| 31 | |
| 32 | extern "C" { |
| 33 | |
| 34 | // This is the stable C ABI that backs art_api::dex below. Structs and functions |
| 35 | // may only be added here. |
| 36 | // TODO(b/120978655): Move this to a separate pure C header. |
| 37 | // |
| 38 | // Clients should use the C++ wrappers in art_api::dex instead. |
| 39 | |
| 40 | // Opaque wrapper for an std::string allocated in libdexfile which must be freed |
| 41 | // using ExtDexFileFreeString. |
| 42 | class ExtDexFileString; |
| 43 | |
| 44 | // Returns an ExtDexFileString initialized to the given string. |
| 45 | const ExtDexFileString* ExtDexFileMakeString(const char* str); |
| 46 | |
| 47 | // Returns a pointer to the underlying null-terminated character array and its |
| 48 | // size for the given ExtDexFileString. |
| 49 | const char* ExtDexFileGetString(const ExtDexFileString* ext_string, /*out*/ size_t* size); |
| 50 | |
| 51 | // Frees an ExtDexFileString. |
| 52 | void ExtDexFileFreeString(const ExtDexFileString* ext_string); |
| 53 | |
| 54 | struct ExtDexFileMethodInfo { |
| 55 | int32_t offset; |
| 56 | int32_t len; |
| 57 | const ExtDexFileString* name; |
| 58 | }; |
| 59 | |
| 60 | class ExtDexFile; |
| 61 | |
| 62 | // See art_api::dex::DexFile::OpenFromMemory. Returns true on success. |
| 63 | int ExtDexFileOpenFromMemory(const void* addr, |
| 64 | /*inout*/ size_t* size, |
| 65 | const char* location, |
| 66 | /*out*/ const ExtDexFileString** error_msg, |
| 67 | /*out*/ ExtDexFile** ext_dex_file); |
| 68 | |
| 69 | // See art_api::dex::DexFile::OpenFromFd. Returns true on success. |
| 70 | int ExtDexFileOpenFromFd(int fd, |
| 71 | off_t offset, |
| 72 | const char* location, |
| 73 | /*out*/ const ExtDexFileString** error_msg, |
| 74 | /*out*/ ExtDexFile** ext_dex_file); |
| 75 | |
| 76 | // See art_api::dex::DexFile::GetMethodInfoForOffset. Returns true on success. |
| 77 | int ExtDexFileGetMethodInfoForOffset(ExtDexFile* ext_dex_file, |
| 78 | int64_t dex_offset, |
| 79 | /*out*/ ExtDexFileMethodInfo* method_info); |
| 80 | |
| 81 | typedef void ExtDexFileMethodInfoCallback(const ExtDexFileMethodInfo* ext_method_info, |
| 82 | void* user_data); |
| 83 | |
| 84 | // See art_api::dex::DexFile::GetAllMethodInfos. |
| 85 | void ExtDexFileGetAllMethodInfos(ExtDexFile* ext_dex_file, |
| 86 | int with_signature, |
| 87 | ExtDexFileMethodInfoCallback* method_info_cb, |
| 88 | void* user_data); |
| 89 | |
| 90 | // Frees an ExtDexFile. |
| 91 | void ExtDexFileFree(ExtDexFile* ext_dex_file); |
| 92 | |
| 93 | } // extern "C" |
| 94 | |
| 95 | namespace art_api { |
| 96 | namespace dex { |
| 97 | |
| 98 | // Minimal std::string look-alike for a string returned from libdexfile. |
| 99 | class DexString final { |
| 100 | public: |
| 101 | DexString(DexString&& dex_str) { ReplaceExtString(std::move(dex_str)); } |
| 102 | explicit DexString(const char* str = "") : ext_string_(ExtDexFileMakeString(str)) {} |
| 103 | ~DexString() { ExtDexFileFreeString(ext_string_); } |
| 104 | |
| 105 | DexString& operator=(DexString&& dex_str) { |
| 106 | ReplaceExtString(std::move(dex_str)); |
| 107 | return *this; |
| 108 | } |
| 109 | |
| 110 | const char* data() const { |
| 111 | size_t ignored; |
| 112 | return ExtDexFileGetString(ext_string_, &ignored); |
| 113 | } |
| 114 | const char* c_str() const { return data(); } |
| 115 | |
| 116 | size_t size() const { |
| 117 | size_t len; |
| 118 | (void)ExtDexFileGetString(ext_string_, &len); |
| 119 | return len; |
| 120 | } |
| 121 | size_t length() const { return size(); } |
| 122 | |
| 123 | operator std::string_view() const { |
| 124 | size_t len; |
| 125 | const char* chars = ExtDexFileGetString(ext_string_, &len); |
| 126 | return std::string_view(chars, len); |
| 127 | } |
| 128 | |
| 129 | private: |
| 130 | friend class DexFile; |
| 131 | friend bool operator==(const DexString&, const DexString&); |
| 132 | explicit DexString(const ExtDexFileString* ext_string) : ext_string_(ext_string) {} |
| 133 | const ExtDexFileString* ext_string_; // Owned instance. Never nullptr. |
| 134 | |
| 135 | void ReplaceExtString(DexString&& dex_str) { |
| 136 | ext_string_ = dex_str.ext_string_; |
| 137 | dex_str.ext_string_ = ExtDexFileMakeString(""); |
| 138 | } |
| 139 | |
| 140 | DISALLOW_COPY_AND_ASSIGN(DexString); |
| 141 | }; |
| 142 | |
| 143 | inline bool operator==(const DexString& s1, const DexString& s2) { |
| 144 | size_t l1, l2; |
| 145 | const char* str1 = ExtDexFileGetString(s1.ext_string_, &l1); |
| 146 | const char* str2 = ExtDexFileGetString(s2.ext_string_, &l2); |
| 147 | // Use memcmp to avoid assumption about absence of null characters in the strings. |
| 148 | return l1 == l2 && !std::memcmp(str1, str2, l1); |
| 149 | } |
| 150 | |
| 151 | struct MethodInfo { |
| 152 | int32_t offset; // Code offset relative to the start of the dex file header |
| 153 | int32_t len; // Code length |
| 154 | DexString name; |
| 155 | }; |
| 156 | |
| 157 | inline bool operator==(const MethodInfo& s1, const MethodInfo& s2) { |
| 158 | return s1.offset == s2.offset && s1.len == s2.len && s1.name == s2.name; |
| 159 | } |
| 160 | |
| 161 | // External stable API to access ordinary dex files and CompactDex. This wraps |
| 162 | // the stable C ABI and handles instance ownership. Thread-compatible but not |
| 163 | // thread-safe. |
| 164 | class DexFile { |
| 165 | public: |
| 166 | DexFile(DexFile&& dex_file) { |
| 167 | ext_dex_file_ = dex_file.ext_dex_file_; |
| 168 | dex_file.ext_dex_file_ = nullptr; |
| 169 | } |
| 170 | virtual ~DexFile(); |
| 171 | |
| 172 | // Interprets a chunk of memory as a dex file. As long as *size is too small, |
| 173 | // returns nullptr, sets *size to a new size to try again with, and sets |
| 174 | // *error_msg to "". That might happen repeatedly. Also returns nullptr |
| 175 | // on error in which case *error_msg is set to a nonempty string. |
| 176 | // |
| 177 | // location is a string that describes the dex file, and is preferably its |
| 178 | // path. It is mostly used to make error messages better, and may be "". |
| 179 | // |
| 180 | // The caller must retain the memory. |
| 181 | static std::unique_ptr<DexFile> OpenFromMemory(const void* addr, |
| 182 | size_t* size, |
| 183 | const std::string& location, |
| 184 | /*out*/ std::string* error_msg) { |
| 185 | ExtDexFile* ext_dex_file; |
| 186 | const ExtDexFileString* ext_error_msg = nullptr; |
| 187 | if (ExtDexFileOpenFromMemory(addr, size, location.c_str(), &ext_error_msg, &ext_dex_file)) { |
| 188 | return std::unique_ptr<DexFile>(new DexFile(ext_dex_file)); |
| 189 | } |
| 190 | *error_msg = (ext_error_msg == nullptr) ? "" : std::string(DexString(ext_error_msg)); |
| 191 | return nullptr; |
| 192 | } |
| 193 | |
| 194 | // mmaps the given file offset in the open fd and reads a dexfile from there. |
| 195 | // Returns nullptr on error in which case *error_msg is set. |
| 196 | // |
| 197 | // location is a string that describes the dex file, and is preferably its |
| 198 | // path. It is mostly used to make error messages better, and may be "". |
| 199 | static std::unique_ptr<DexFile> OpenFromFd(int fd, |
| 200 | off_t offset, |
| 201 | const std::string& location, |
| 202 | /*out*/ std::string* error_msg) { |
| 203 | ExtDexFile* ext_dex_file; |
| 204 | const ExtDexFileString* ext_error_msg = nullptr; |
| 205 | if (ExtDexFileOpenFromFd(fd, offset, location.c_str(), &ext_error_msg, &ext_dex_file)) { |
| 206 | return std::unique_ptr<DexFile>(new DexFile(ext_dex_file)); |
| 207 | } |
| 208 | *error_msg = std::string(DexString(ext_error_msg)); |
| 209 | return nullptr; |
| 210 | } |
| 211 | |
| 212 | // Given an offset relative to the start of the dex file header, if there is a |
| 213 | // method whose instruction range includes that offset then returns info about |
| 214 | // it, otherwise returns a struct with offset == 0. |
| 215 | MethodInfo GetMethodInfoForOffset(int64_t dex_offset) { |
| 216 | ExtDexFileMethodInfo ext_method_info; |
| 217 | if (ExtDexFileGetMethodInfoForOffset(ext_dex_file_, dex_offset, &ext_method_info)) { |
| 218 | return AbsorbMethodInfo(ext_method_info); |
| 219 | } |
| 220 | return {/*offset=*/0, /*len=*/0, /*name=*/DexString()}; |
| 221 | } |
| 222 | |
| 223 | // Returns info structs about all methods in the dex file. MethodInfo.name |
| 224 | // receives the full function signature if with_signature is set, otherwise it |
| 225 | // gets the class and method name only. |
| 226 | std::vector<MethodInfo> GetAllMethodInfos(bool with_signature = true) { |
| 227 | MethodInfoVector res; |
| 228 | ExtDexFileGetAllMethodInfos( |
| 229 | ext_dex_file_, with_signature, AddMethodInfoCallback, static_cast<void*>(&res)); |
| 230 | return res; |
| 231 | } |
| 232 | |
| 233 | private: |
| 234 | explicit DexFile(ExtDexFile* ext_dex_file) : ext_dex_file_(ext_dex_file) {} |
| 235 | ExtDexFile* ext_dex_file_; // Owned instance. nullptr only in moved-from zombies. |
| 236 | |
| 237 | typedef std::vector<MethodInfo> MethodInfoVector; |
| 238 | |
| 239 | static MethodInfo AbsorbMethodInfo(const ExtDexFileMethodInfo& ext_method_info); |
| 240 | static void AddMethodInfoCallback(const ExtDexFileMethodInfo* ext_method_info, void* user_data); |
| 241 | |
| 242 | DISALLOW_COPY_AND_ASSIGN(DexFile); |
| 243 | }; |
| 244 | |
| 245 | } // namespace dex |
| 246 | } // namespace art_api |
| 247 | |
| 248 | #endif // ART_LIBDEXFILE_EXTERNAL_INCLUDE_ART_API_EXT_DEX_FILE_H_ |