1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/pickle.h" 6 7 #include <stdlib.h> 8 9 #include <algorithm> // for max() 10 11 //------------------------------------------------------------------------------ 12 13 // static 14 const int Pickle::kPayloadUnit = 64; 15 16 static const size_t kCapacityReadOnly = static_cast<size_t>(-1); 17 18 PickleIterator::PickleIterator(const Pickle& pickle) 19 : read_ptr_(pickle.payload()), 20 read_end_ptr_(pickle.end_of_payload()) { 21 } 22 23 template <typename Type> 24 inline bool PickleIterator::ReadBuiltinType(Type* result) { 25 const char* read_from = GetReadPointerAndAdvance<Type>(); 26 if (!read_from) 27 return false; 28 if (sizeof(Type) > sizeof(uint32)) 29 memcpy(result, read_from, sizeof(*result)); 30 else 31 *result = *reinterpret_cast<const Type*>(read_from); 32 return true; 33 } 34 35 template<typename Type> 36 inline const char* PickleIterator::GetReadPointerAndAdvance() { 37 const char* current_read_ptr = read_ptr_; 38 if (read_ptr_ + sizeof(Type) > read_end_ptr_) 39 return NULL; 40 if (sizeof(Type) < sizeof(uint32)) 41 read_ptr_ += AlignInt(sizeof(Type), sizeof(uint32)); 42 else 43 read_ptr_ += sizeof(Type); 44 return current_read_ptr; 45 } 46 47 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) { 48 if (num_bytes < 0 || read_end_ptr_ - read_ptr_ < num_bytes) 49 return NULL; 50 const char* current_read_ptr = read_ptr_; 51 read_ptr_ += AlignInt(num_bytes, sizeof(uint32)); 52 return current_read_ptr; 53 } 54 55 inline const char* PickleIterator::GetReadPointerAndAdvance(int num_elements, 56 size_t size_element) { 57 // Check for int32 overflow. 58 int64 num_bytes = static_cast<int64>(num_elements) * size_element; 59 int num_bytes32 = static_cast<int>(num_bytes); 60 if (num_bytes != static_cast<int64>(num_bytes32)) 61 return NULL; 62 return GetReadPointerAndAdvance(num_bytes32); 63 } 64 65 bool PickleIterator::ReadBool(bool* result) { 66 return ReadBuiltinType(result); 67 } 68 69 bool PickleIterator::ReadInt(int* result) { 70 return ReadBuiltinType(result); 71 } 72 73 bool PickleIterator::ReadLong(long* result) { 74 return ReadBuiltinType(result); 75 } 76 77 bool PickleIterator::ReadUInt16(uint16* result) { 78 return ReadBuiltinType(result); 79 } 80 81 bool PickleIterator::ReadUInt32(uint32* result) { 82 return ReadBuiltinType(result); 83 } 84 85 bool PickleIterator::ReadInt64(int64* result) { 86 return ReadBuiltinType(result); 87 } 88 89 bool PickleIterator::ReadUInt64(uint64* result) { 90 return ReadBuiltinType(result); 91 } 92 93 bool PickleIterator::ReadFloat(float* result) { 94 return ReadBuiltinType(result); 95 } 96 97 bool PickleIterator::ReadString(std::string* result) { 98 int len; 99 if (!ReadInt(&len)) 100 return false; 101 const char* read_from = GetReadPointerAndAdvance(len); 102 if (!read_from) 103 return false; 104 105 result->assign(read_from, len); 106 return true; 107 } 108 109 bool PickleIterator::ReadWString(std::wstring* result) { 110 int len; 111 if (!ReadInt(&len)) 112 return false; 113 const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t)); 114 if (!read_from) 115 return false; 116 117 result->assign(reinterpret_cast<const wchar_t*>(read_from), len); 118 return true; 119 } 120 121 bool PickleIterator::ReadString16(string16* result) { 122 int len; 123 if (!ReadInt(&len)) 124 return false; 125 const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16)); 126 if (!read_from) 127 return false; 128 129 result->assign(reinterpret_cast<const char16*>(read_from), len); 130 return true; 131 } 132 133 bool PickleIterator::ReadData(const char** data, int* length) { 134 *length = 0; 135 *data = 0; 136 137 if (!ReadInt(length)) 138 return false; 139 140 return ReadBytes(data, *length); 141 } 142 143 bool PickleIterator::ReadBytes(const char** data, int length) { 144 const char* read_from = GetReadPointerAndAdvance(length); 145 if (!read_from) 146 return false; 147 *data = read_from; 148 return true; 149 } 150 151 // Payload is uint32 aligned. 152 153 Pickle::Pickle() 154 : header_(NULL), 155 header_size_(sizeof(Header)), 156 capacity_(0), 157 variable_buffer_offset_(0) { 158 Resize(kPayloadUnit); 159 header_->payload_size = 0; 160 } 161 162 Pickle::Pickle(int header_size) 163 : header_(NULL), 164 header_size_(AlignInt(header_size, sizeof(uint32))), 165 capacity_(0), 166 variable_buffer_offset_(0) { 167 DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header)); 168 DCHECK_LE(header_size, kPayloadUnit); 169 Resize(kPayloadUnit); 170 header_->payload_size = 0; 171 } 172 173 Pickle::Pickle(const char* data, int data_len) 174 : header_(reinterpret_cast<Header*>(const_cast<char*>(data))), 175 header_size_(0), 176 capacity_(kCapacityReadOnly), 177 variable_buffer_offset_(0) { 178 if (data_len >= static_cast<int>(sizeof(Header))) 179 header_size_ = data_len - header_->payload_size; 180 181 if (header_size_ > static_cast<unsigned int>(data_len)) 182 header_size_ = 0; 183 184 if (header_size_ != AlignInt(header_size_, sizeof(uint32))) 185 header_size_ = 0; 186 187 // If there is anything wrong with the data, we're not going to use it. 188 if (!header_size_) 189 header_ = NULL; 190 } 191 192 Pickle::Pickle(const Pickle& other) 193 : header_(NULL), 194 header_size_(other.header_size_), 195 capacity_(0), 196 variable_buffer_offset_(other.variable_buffer_offset_) { 197 size_t payload_size = header_size_ + other.header_->payload_size; 198 bool resized = Resize(payload_size); 199 CHECK(resized); // Realloc failed. 200 memcpy(header_, other.header_, payload_size); 201 } 202 203 Pickle::~Pickle() { 204 if (capacity_ != kCapacityReadOnly) 205 free(header_); 206 } 207 208 Pickle& Pickle::operator=(const Pickle& other) { 209 if (this == &other) { 210 NOTREACHED(); 211 return *this; 212 } 213 if (capacity_ == kCapacityReadOnly) { 214 header_ = NULL; 215 capacity_ = 0; 216 } 217 if (header_size_ != other.header_size_) { 218 free(header_); 219 header_ = NULL; 220 header_size_ = other.header_size_; 221 } 222 bool resized = Resize(other.header_size_ + other.header_->payload_size); 223 CHECK(resized); // Realloc failed. 224 memcpy(header_, other.header_, 225 other.header_size_ + other.header_->payload_size); 226 variable_buffer_offset_ = other.variable_buffer_offset_; 227 return *this; 228 } 229 230 bool Pickle::WriteString(const std::string& value) { 231 if (!WriteInt(static_cast<int>(value.size()))) 232 return false; 233 234 return WriteBytes(value.data(), static_cast<int>(value.size())); 235 } 236 237 bool Pickle::WriteWString(const std::wstring& value) { 238 if (!WriteInt(static_cast<int>(value.size()))) 239 return false; 240 241 return WriteBytes(value.data(), 242 static_cast<int>(value.size() * sizeof(wchar_t))); 243 } 244 245 bool Pickle::WriteString16(const string16& value) { 246 if (!WriteInt(static_cast<int>(value.size()))) 247 return false; 248 249 return WriteBytes(value.data(), 250 static_cast<int>(value.size()) * sizeof(char16)); 251 } 252 253 bool Pickle::WriteData(const char* data, int length) { 254 return length >= 0 && WriteInt(length) && WriteBytes(data, length); 255 } 256 257 bool Pickle::WriteBytes(const void* data, int data_len) { 258 DCHECK_NE(kCapacityReadOnly, capacity_) << "oops: pickle is readonly"; 259 260 char* dest = BeginWrite(data_len); 261 if (!dest) 262 return false; 263 264 memcpy(dest, data, data_len); 265 266 EndWrite(dest, data_len); 267 return true; 268 } 269 270 char* Pickle::BeginWriteData(int length) { 271 DCHECK_EQ(variable_buffer_offset_, 0U) << 272 "There can only be one variable buffer in a Pickle"; 273 274 if (length < 0 || !WriteInt(length)) 275 return NULL; 276 277 char *data_ptr = BeginWrite(length); 278 if (!data_ptr) 279 return NULL; 280 281 variable_buffer_offset_ = 282 data_ptr - reinterpret_cast<char*>(header_) - sizeof(int); 283 284 // EndWrite doesn't necessarily have to be called after the write operation, 285 // so we call it here to pad out what the caller will eventually write. 286 EndWrite(data_ptr, length); 287 return data_ptr; 288 } 289 290 void Pickle::TrimWriteData(int new_length) { 291 DCHECK_NE(variable_buffer_offset_, 0U); 292 293 // Fetch the the variable buffer size 294 int* cur_length = reinterpret_cast<int*>( 295 reinterpret_cast<char*>(header_) + variable_buffer_offset_); 296 297 if (new_length < 0 || new_length > *cur_length) { 298 NOTREACHED() << "Invalid length in TrimWriteData."; 299 return; 300 } 301 302 // Update the payload size and variable buffer size 303 header_->payload_size -= (*cur_length - new_length); 304 *cur_length = new_length; 305 } 306 307 char* Pickle::BeginWrite(size_t length) { 308 // write at a uint32-aligned offset from the beginning of the header 309 size_t offset = AlignInt(header_->payload_size, sizeof(uint32)); 310 311 size_t new_size = offset + length; 312 size_t needed_size = header_size_ + new_size; 313 if (needed_size > capacity_ && !Resize(std::max(capacity_ * 2, needed_size))) 314 return NULL; 315 316 #ifdef ARCH_CPU_64_BITS 317 DCHECK_LE(length, kuint32max); 318 #endif 319 320 header_->payload_size = static_cast<uint32>(new_size); 321 return mutable_payload() + offset; 322 } 323 324 void Pickle::EndWrite(char* dest, int length) { 325 // Zero-pad to keep tools like valgrind from complaining about uninitialized 326 // memory. 327 if (length % sizeof(uint32)) 328 memset(dest + length, 0, sizeof(uint32) - (length % sizeof(uint32))); 329 } 330 331 bool Pickle::Resize(size_t new_capacity) { 332 new_capacity = AlignInt(new_capacity, kPayloadUnit); 333 334 CHECK_NE(capacity_, kCapacityReadOnly); 335 void* p = realloc(header_, new_capacity); 336 if (!p) 337 return false; 338 339 header_ = reinterpret_cast<Header*>(p); 340 capacity_ = new_capacity; 341 return true; 342 } 343 344 // static 345 const char* Pickle::FindNext(size_t header_size, 346 const char* start, 347 const char* end) { 348 DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32))); 349 DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit)); 350 351 if (static_cast<size_t>(end - start) < sizeof(Header)) 352 return NULL; 353 354 const Header* hdr = reinterpret_cast<const Header*>(start); 355 const char* payload_base = start + header_size; 356 const char* payload_end = payload_base + hdr->payload_size; 357 if (payload_end < payload_base) 358 return NULL; 359 360 return (payload_end > end) ? NULL : payload_end; 361 } 362
