base/pickle.cc

   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 using base::char16;
  14 using base::string16;
  15
  16 // static
  17 const int Pickle::kPayloadUnit = 64;
  18
  19 static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
  20
  21 PickleIterator::PickleIterator(const Pickle& pickle)
  22     : payload_(pickle.payload()),
  23       read_index_(0),
  24       end_index_(pickle.payload_size()) {
  25 }
  26
  27 template <typename Type>
  28 inline bool PickleIterator::ReadBuiltinType(Type* result) {
  29   const char* read_from = GetReadPointerAndAdvance<Type>();
  30   if (!read_from)
  31     return false;
  32   if (sizeof(Type) > sizeof(uint32))
  33     memcpy(result, read_from, sizeof(*result));
  34   else
  35     *result = *reinterpret_cast<const Type*>(read_from);
  36   return true;
  37 }
  38
  39 inline void PickleIterator::Advance(size_t size) {
  40   size_t aligned_size = AlignInt(size, sizeof(uint32_t));
  41   if (end_index_ - read_index_ < aligned_size) {
  42     read_index_ = end_index_;
  43   } else {
  44     read_index_ += aligned_size;
  45   }
  46 }
  47
  48 template<typename Type>
  49 inline const char* PickleIterator::GetReadPointerAndAdvance() {
  50   if (sizeof(Type) > end_index_ - read_index_) {
  51     read_index_ = end_index_;
  52     return NULL;
  53   }
  54   const char* current_read_ptr = payload_ + read_index_;
  55   Advance(sizeof(Type));
  56   return current_read_ptr;
  57 }
  58
  59 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
  60   if (num_bytes < 0 ||
  61       end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
  62     read_index_ = end_index_;
  63     return NULL;
  64   }
  65   const char* current_read_ptr = payload_ + read_index_;
  66   Advance(num_bytes);
  67   return current_read_ptr;
  68 }
  69
  70 inline const char* PickleIterator::GetReadPointerAndAdvance(
  71     int num_elements,
  72     size_t size_element) {
  73   // Check for int32 overflow.
  74   int64 num_bytes = static_cast<int64>(num_elements) * size_element;
  75   int num_bytes32 = static_cast<int>(num_bytes);
  76   if (num_bytes != static_cast<int64>(num_bytes32))
  77     return NULL;
  78   return GetReadPointerAndAdvance(num_bytes32);
  79 }
  80
  81 bool PickleIterator::ReadBool(bool* result) {
  82   return ReadBuiltinType(result);
  83 }
  84
  85 bool PickleIterator::ReadInt(int* result) {
  86   return ReadBuiltinType(result);
  87 }
  88
  89 bool PickleIterator::ReadLong(long* result) {
  90   return ReadBuiltinType(result);
  91 }
  92
  93 bool PickleIterator::ReadUInt16(uint16* result) {
  94   return ReadBuiltinType(result);
  95 }
  96
  97 bool PickleIterator::ReadUInt32(uint32* result) {
  98   return ReadBuiltinType(result);
  99 }
 100
 101 bool PickleIterator::ReadInt64(int64* result) {
 102   return ReadBuiltinType(result);
 103 }
 104
 105 bool PickleIterator::ReadUInt64(uint64* result) {
 106   return ReadBuiltinType(result);
 107 }
 108
 109 bool PickleIterator::ReadSizeT(size_t* result) {
 110   // Always read size_t as a 64-bit value to ensure compatibility between 32-bit
 111   // and 64-bit processes.
 112   uint64 result_uint64 = 0;
 113   bool success = ReadBuiltinType(&result_uint64);
 114   *result = static_cast<size_t>(result_uint64);
 115   // Fail if the cast above truncates the value.
 116   return success && (*result == result_uint64);
 117 }
 118
 119 bool PickleIterator::ReadFloat(float* result) {
 120   // crbug.com/315213
 121   // The source data may not be properly aligned, and unaligned float reads
 122   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 123   // into the result.
 124   const char* read_from = GetReadPointerAndAdvance<float>();
 125   if (!read_from)
 126     return false;
 127   memcpy(result, read_from, sizeof(*result));
 128   return true;
 129 }
 130
 131 bool PickleIterator::ReadDouble(double* result) {
 132   // crbug.com/315213
 133   // The source data may not be properly aligned, and unaligned double reads
 134   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 135   // into the result.
 136   const char* read_from = GetReadPointerAndAdvance<double>();
 137   if (!read_from)
 138     return false;
 139   memcpy(result, read_from, sizeof(*result));
 140   return true;
 141 }
 142
 143 bool PickleIterator::ReadString(std::string* result) {
 144   int len;
 145   if (!ReadInt(&len))
 146     return false;
 147   const char* read_from = GetReadPointerAndAdvance(len);
 148   if (!read_from)
 149     return false;
 150
 151   result->assign(read_from, len);
 152   return true;
 153 }
 154
 155 bool PickleIterator::ReadWString(std::wstring* result) {
 156   int len;
 157   if (!ReadInt(&len))
 158     return false;
 159   const char* read_from = GetReadPointerAndAdvance(len, sizeof(wchar_t));
 160   if (!read_from)
 161     return false;
 162
 163   result->assign(reinterpret_cast<const wchar_t*>(read_from), len);
 164   return true;
 165 }
 166
 167 bool PickleIterator::ReadString16(string16* result) {
 168   int len;
 169   if (!ReadInt(&len))
 170     return false;
 171   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
 172   if (!read_from)
 173     return false;
 174
 175   result->assign(reinterpret_cast<const char16*>(read_from), len);
 176   return true;
 177 }
 178
 179 bool PickleIterator::ReadData(const char** data, int* length) {
 180   *length = 0;
 181   *data = 0;
 182
 183   if (!ReadInt(length))
 184     return false;
 185
 186   return ReadBytes(data, *length);
 187 }
 188
 189 bool PickleIterator::ReadBytes(const char** data, int length) {
 190   const char* read_from = GetReadPointerAndAdvance(length);
 191   if (!read_from)
 192     return false;
 193   *data = read_from;
 194   return true;
 195 }
 196
 197 // Payload is uint32 aligned.
 198
 199 Pickle::Pickle()
 200     : header_(NULL),
 201       header_size_(sizeof(Header)),
 202       capacity_after_header_(0),
 203       write_offset_(0) {
 204   Resize(kPayloadUnit);
 205   header_->payload_size = 0;
 206 }
 207
 208 Pickle::Pickle(int header_size)
 209     : header_(NULL),
 210       header_size_(AlignInt(header_size, sizeof(uint32))),
 211       capacity_after_header_(0),
 212       write_offset_(0) {
 213   DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
 214   DCHECK_LE(header_size, kPayloadUnit);
 215   Resize(kPayloadUnit);
 216   header_->payload_size = 0;
 217 }
 218
 219 Pickle::Pickle(const char* data, int data_len)
 220     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
 221       header_size_(0),
 222       capacity_after_header_(kCapacityReadOnly),
 223       write_offset_(0) {
 224   if (data_len >= static_cast<int>(sizeof(Header)))
 225     header_size_ = data_len - header_->payload_size;
 226
 227   if (header_size_ > static_cast<unsigned int>(data_len))
 228     header_size_ = 0;
 229
 230   if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
 231     header_size_ = 0;
 232
 233   // If there is anything wrong with the data, we're not going to use it.
 234   if (!header_size_)
 235     header_ = NULL;
 236 }
 237
 238 Pickle::Pickle(const Pickle& other)
 239     : header_(NULL),
 240       header_size_(other.header_size_),
 241       capacity_after_header_(0),
 242       write_offset_(other.write_offset_) {
 243   size_t payload_size = header_size_ + other.header_->payload_size;
 244   Resize(payload_size);
 245   memcpy(header_, other.header_, payload_size);
 246 }
 247
 248 Pickle::~Pickle() {
 249   if (capacity_after_header_ != kCapacityReadOnly)
 250     free(header_);
 251 }
 252
 253 Pickle& Pickle::operator=(const Pickle& other) {
 254   if (this == &other) {
 255     NOTREACHED();
 256     return *this;
 257   }
 258   if (capacity_after_header_ == kCapacityReadOnly) {
 259     header_ = NULL;
 260     capacity_after_header_ = 0;
 261   }
 262   if (header_size_ != other.header_size_) {
 263     free(header_);
 264     header_ = NULL;
 265     header_size_ = other.header_size_;
 266   }
 267   Resize(other.header_->payload_size);
 268   memcpy(header_, other.header_,
 269          other.header_size_ + other.header_->payload_size);
 270   write_offset_ = other.write_offset_;
 271   return *this;
 272 }
 273
 274 bool Pickle::WriteString(const std::string& value) {
 275   if (!WriteInt(static_cast<int>(value.size())))
 276     return false;
 277
 278   return WriteBytes(value.data(), static_cast<int>(value.size()));
 279 }
 280
 281 bool Pickle::WriteWString(const std::wstring& value) {
 282   if (!WriteInt(static_cast<int>(value.size())))
 283     return false;
 284
 285   return WriteBytes(value.data(),
 286                     static_cast<int>(value.size() * sizeof(wchar_t)));
 287 }
 288
 289 bool Pickle::WriteString16(const string16& value) {
 290   if (!WriteInt(static_cast<int>(value.size())))
 291     return false;
 292
 293   return WriteBytes(value.data(),
 294                     static_cast<int>(value.size()) * sizeof(char16));
 295 }
 296
 297 bool Pickle::WriteData(const char* data, int length) {
 298   return length >= 0 && WriteInt(length) && WriteBytes(data, length);
 299 }
 300
 301 bool Pickle::WriteBytes(const void* data, int length) {
 302   WriteBytesCommon(data, length);
 303   return true;
 304 }
 305
 306 void Pickle::Reserve(size_t length) {
 307   size_t data_len = AlignInt(length, sizeof(uint32));
 308   DCHECK_GE(data_len, length);
 309 #ifdef ARCH_CPU_64_BITS
 310   DCHECK_LE(data_len, kuint32max);
 311 #endif
 312   DCHECK_LE(write_offset_, kuint32max - data_len);
 313   size_t new_size = write_offset_ + data_len;
 314   if (new_size > capacity_after_header_)
 315     Resize(capacity_after_header_ * 2 + new_size);
 316 }
 317
 318 void Pickle::Resize(size_t new_capacity) {
 319   new_capacity = AlignInt(new_capacity, kPayloadUnit);
 320
 321   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
 322   void* p = realloc(header_, header_size_ + new_capacity);
 323   CHECK(p);
 324   header_ = reinterpret_cast<Header*>(p);
 325   capacity_after_header_ = new_capacity;
 326 }
 327
 328 // static
 329 const char* Pickle::FindNext(size_t header_size,
 330                              const char* start,
 331                              const char* end) {
 332   DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
 333   DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
 334
 335   size_t length = static_cast<size_t>(end - start);
 336   if (length < sizeof(Header))
 337     return NULL;
 338
 339   const Header* hdr = reinterpret_cast<const Header*>(start);
 340   if (length < header_size || length - header_size < hdr->payload_size)
 341     return NULL;
 342   return start + header_size + hdr->payload_size;
 343 }
 344
 345 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
 346   WriteBytesCommon(data, length);
 347 }
 348
 349 template void Pickle::WriteBytesStatic<2>(const void* data);
 350 template void Pickle::WriteBytesStatic<4>(const void* data);
 351 template void Pickle::WriteBytesStatic<8>(const void* data);
 352
 353 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
 354   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
 355       << "oops: pickle is readonly";
 356   size_t data_len = AlignInt(length, sizeof(uint32));
 357   DCHECK_GE(data_len, length);
 358 #ifdef ARCH_CPU_64_BITS
 359   DCHECK_LE(data_len, kuint32max);
 360 #endif
 361   DCHECK_LE(write_offset_, kuint32max - data_len);
 362   size_t new_size = write_offset_ + data_len;
 363   if (new_size > capacity_after_header_) {
 364     Resize(std::max(capacity_after_header_ * 2, new_size));
 365   }
 366
 367   char* write = mutable_payload() + write_offset_;
 368   memcpy(write, data, length);
 369   memset(write + length, 0, data_len - length);
 370   header_->payload_size = static_cast<uint32>(new_size);
 371   write_offset_ = new_size;
 372 }