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 namespace base {
  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     : payload_(pickle.payload()),
  20       read_index_(0),
  21       end_index_(pickle.payload_size()) {
  22 }
  23
  24 template <typename Type>
  25 inline bool PickleIterator::ReadBuiltinType(Type* result) {
  26   const char* read_from = GetReadPointerAndAdvance<Type>();
  27   if (!read_from)
  28     return false;
  29   if (sizeof(Type) > sizeof(uint32))
  30     memcpy(result, read_from, sizeof(*result));
  31   else
  32     *result = *reinterpret_cast<const Type*>(read_from);
  33   return true;
  34 }
  35
  36 inline void PickleIterator::Advance(size_t size) {
  37   size_t aligned_size = AlignInt(size, sizeof(uint32_t));
  38   if (end_index_ - read_index_ < aligned_size) {
  39     read_index_ = end_index_;
  40   } else {
  41     read_index_ += aligned_size;
  42   }
  43 }
  44
  45 template<typename Type>
  46 inline const char* PickleIterator::GetReadPointerAndAdvance() {
  47   if (sizeof(Type) > end_index_ - read_index_) {
  48     read_index_ = end_index_;
  49     return NULL;
  50   }
  51   const char* current_read_ptr = payload_ + read_index_;
  52   Advance(sizeof(Type));
  53   return current_read_ptr;
  54 }
  55
  56 const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
  57   if (num_bytes < 0 ||
  58       end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
  59     read_index_ = end_index_;
  60     return NULL;
  61   }
  62   const char* current_read_ptr = payload_ + read_index_;
  63   Advance(num_bytes);
  64   return current_read_ptr;
  65 }
  66
  67 inline const char* PickleIterator::GetReadPointerAndAdvance(
  68     int num_elements,
  69     size_t size_element) {
  70   // Check for int32 overflow.
  71   int64 num_bytes = static_cast<int64>(num_elements) * size_element;
  72   int num_bytes32 = static_cast<int>(num_bytes);
  73   if (num_bytes != static_cast<int64>(num_bytes32))
  74     return NULL;
  75   return GetReadPointerAndAdvance(num_bytes32);
  76 }
  77
  78 bool PickleIterator::ReadBool(bool* result) {
  79   return ReadBuiltinType(result);
  80 }
  81
  82 bool PickleIterator::ReadInt(int* result) {
  83   return ReadBuiltinType(result);
  84 }
  85
  86 bool PickleIterator::ReadLong(long* result) {
  87   return ReadBuiltinType(result);
  88 }
  89
  90 bool PickleIterator::ReadUInt16(uint16* result) {
  91   return ReadBuiltinType(result);
  92 }
  93
  94 bool PickleIterator::ReadUInt32(uint32* result) {
  95   return ReadBuiltinType(result);
  96 }
  97
  98 bool PickleIterator::ReadInt64(int64* result) {
  99   return ReadBuiltinType(result);
 100 }
 101
 102 bool PickleIterator::ReadUInt64(uint64* result) {
 103   return ReadBuiltinType(result);
 104 }
 105
 106 bool PickleIterator::ReadSizeT(size_t* result) {
 107   // Always read size_t as a 64-bit value to ensure compatibility between 32-bit
 108   // and 64-bit processes.
 109   uint64 result_uint64 = 0;
 110   bool success = ReadBuiltinType(&result_uint64);
 111   *result = static_cast<size_t>(result_uint64);
 112   // Fail if the cast above truncates the value.
 113   return success && (*result == result_uint64);
 114 }
 115
 116 bool PickleIterator::ReadFloat(float* result) {
 117   // crbug.com/315213
 118   // The source data may not be properly aligned, and unaligned float reads
 119   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 120   // into the result.
 121   const char* read_from = GetReadPointerAndAdvance<float>();
 122   if (!read_from)
 123     return false;
 124   memcpy(result, read_from, sizeof(*result));
 125   return true;
 126 }
 127
 128 bool PickleIterator::ReadDouble(double* result) {
 129   // crbug.com/315213
 130   // The source data may not be properly aligned, and unaligned double reads
 131   // cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
 132   // into the result.
 133   const char* read_from = GetReadPointerAndAdvance<double>();
 134   if (!read_from)
 135     return false;
 136   memcpy(result, read_from, sizeof(*result));
 137   return true;
 138 }
 139
 140 bool PickleIterator::ReadString(std::string* result) {
 141   int len;
 142   if (!ReadInt(&len))
 143     return false;
 144   const char* read_from = GetReadPointerAndAdvance(len);
 145   if (!read_from)
 146     return false;
 147
 148   result->assign(read_from, len);
 149   return true;
 150 }
 151
 152 bool PickleIterator::ReadStringPiece(StringPiece* result) {
 153   int len;
 154   if (!ReadInt(&len))
 155     return false;
 156   const char* read_from = GetReadPointerAndAdvance(len);
 157   if (!read_from)
 158     return false;
 159
 160   *result = StringPiece(read_from, len);
 161   return true;
 162 }
 163
 164 bool PickleIterator::ReadString16(string16* result) {
 165   int len;
 166   if (!ReadInt(&len))
 167     return false;
 168   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
 169   if (!read_from)
 170     return false;
 171
 172   result->assign(reinterpret_cast<const char16*>(read_from), len);
 173   return true;
 174 }
 175
 176 bool PickleIterator::ReadStringPiece16(StringPiece16* result) {
 177   int len;
 178   if (!ReadInt(&len))
 179     return false;
 180   const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16));
 181   if (!read_from)
 182     return false;
 183
 184   *result = StringPiece16(reinterpret_cast<const char16*>(read_from), len);
 185   return true;
 186 }
 187
 188 bool PickleIterator::ReadData(const char** data, int* length) {
 189   *length = 0;
 190   *data = 0;
 191
 192   if (!ReadInt(length))
 193     return false;
 194
 195   return ReadBytes(data, *length);
 196 }
 197
 198 bool PickleIterator::ReadBytes(const char** data, int length) {
 199   const char* read_from = GetReadPointerAndAdvance(length);
 200   if (!read_from)
 201     return false;
 202   *data = read_from;
 203   return true;
 204 }
 205
 206 // Payload is uint32 aligned.
 207
 208 Pickle::Pickle()
 209     : header_(NULL),
 210       header_size_(sizeof(Header)),
 211       capacity_after_header_(0),
 212       write_offset_(0) {
 213   Resize(kPayloadUnit);
 214   header_->payload_size = 0;
 215 }
 216
 217 Pickle::Pickle(int header_size)
 218     : header_(NULL),
 219       header_size_(AlignInt(header_size, sizeof(uint32))),
 220       capacity_after_header_(0),
 221       write_offset_(0) {
 222   DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
 223   DCHECK_LE(header_size, kPayloadUnit);
 224   Resize(kPayloadUnit);
 225   header_->payload_size = 0;
 226 }
 227
 228 Pickle::Pickle(const char* data, int data_len)
 229     : header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
 230       header_size_(0),
 231       capacity_after_header_(kCapacityReadOnly),
 232       write_offset_(0) {
 233   if (data_len >= static_cast<int>(sizeof(Header)))
 234     header_size_ = data_len - header_->payload_size;
 235
 236   if (header_size_ > static_cast<unsigned int>(data_len))
 237     header_size_ = 0;
 238
 239   if (header_size_ != AlignInt(header_size_, sizeof(uint32)))
 240     header_size_ = 0;
 241
 242   // If there is anything wrong with the data, we're not going to use it.
 243   if (!header_size_)
 244     header_ = NULL;
 245 }
 246
 247 Pickle::Pickle(const Pickle& other)
 248     : header_(NULL),
 249       header_size_(other.header_size_),
 250       capacity_after_header_(0),
 251       write_offset_(other.write_offset_) {
 252   size_t payload_size = header_size_ + other.header_->payload_size;
 253   Resize(payload_size);
 254   memcpy(header_, other.header_, payload_size);
 255 }
 256
 257 Pickle::~Pickle() {
 258   if (capacity_after_header_ != kCapacityReadOnly)
 259     free(header_);
 260 }
 261
 262 Pickle& Pickle::operator=(const Pickle& other) {
 263   if (this == &other) {
 264     NOTREACHED();
 265     return *this;
 266   }
 267   if (capacity_after_header_ == kCapacityReadOnly) {
 268     header_ = NULL;
 269     capacity_after_header_ = 0;
 270   }
 271   if (header_size_ != other.header_size_) {
 272     free(header_);
 273     header_ = NULL;
 274     header_size_ = other.header_size_;
 275   }
 276   Resize(other.header_->payload_size);
 277   memcpy(header_, other.header_,
 278          other.header_size_ + other.header_->payload_size);
 279   write_offset_ = other.write_offset_;
 280   return *this;
 281 }
 282
 283 bool Pickle::WriteString(const StringPiece& value) {
 284   if (!WriteInt(static_cast<int>(value.size())))
 285     return false;
 286
 287   return WriteBytes(value.data(), static_cast<int>(value.size()));
 288 }
 289
 290 bool Pickle::WriteString16(const StringPiece16& value) {
 291   if (!WriteInt(static_cast<int>(value.size())))
 292     return false;
 293
 294   return WriteBytes(value.data(),
 295                     static_cast<int>(value.size()) * sizeof(char16));
 296 }
 297
 298 bool Pickle::WriteData(const char* data, int length) {
 299   return length >= 0 && WriteInt(length) && WriteBytes(data, length);
 300 }
 301
 302 bool Pickle::WriteBytes(const void* data, int length) {
 303   WriteBytesCommon(data, length);
 304   return true;
 305 }
 306
 307 void Pickle::Reserve(size_t length) {
 308   size_t data_len = AlignInt(length, sizeof(uint32));
 309   DCHECK_GE(data_len, length);
 310 #ifdef ARCH_CPU_64_BITS
 311   DCHECK_LE(data_len, kuint32max);
 312 #endif
 313   DCHECK_LE(write_offset_, kuint32max - data_len);
 314   size_t new_size = write_offset_ + data_len;
 315   if (new_size > capacity_after_header_)
 316     Resize(capacity_after_header_ * 2 + new_size);
 317 }
 318
 319 void Pickle::Resize(size_t new_capacity) {
 320   new_capacity = AlignInt(new_capacity, kPayloadUnit);
 321
 322   CHECK_NE(capacity_after_header_, kCapacityReadOnly);
 323   void* p = realloc(header_, header_size_ + new_capacity);
 324   CHECK(p);
 325   header_ = reinterpret_cast<Header*>(p);
 326   capacity_after_header_ = new_capacity;
 327 }
 328
 329 // static
 330 const char* Pickle::FindNext(size_t header_size,
 331                              const char* start,
 332                              const char* end) {
 333   DCHECK_EQ(header_size, AlignInt(header_size, sizeof(uint32)));
 334   DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
 335
 336   size_t length = static_cast<size_t>(end - start);
 337   if (length < sizeof(Header))
 338     return NULL;
 339
 340   const Header* hdr = reinterpret_cast<const Header*>(start);
 341   if (length < header_size || length - header_size < hdr->payload_size)
 342     return NULL;
 343   return start + header_size + hdr->payload_size;
 344 }
 345
 346 template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
 347   WriteBytesCommon(data, length);
 348 }
 349
 350 template void Pickle::WriteBytesStatic<2>(const void* data);
 351 template void Pickle::WriteBytesStatic<4>(const void* data);
 352 template void Pickle::WriteBytesStatic<8>(const void* data);
 353
 354 inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
 355   DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
 356       << "oops: pickle is readonly";
 357   MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
 358   size_t data_len = AlignInt(length, sizeof(uint32));
 359   DCHECK_GE(data_len, length);
 360 #ifdef ARCH_CPU_64_BITS
 361   DCHECK_LE(data_len, kuint32max);
 362 #endif
 363   DCHECK_LE(write_offset_, kuint32max - data_len);
 364   size_t new_size = write_offset_ + data_len;
 365   if (new_size > capacity_after_header_) {
 366     Resize(std::max(capacity_after_header_ * 2, new_size));
 367   }
 368
 369   char* write = mutable_payload() + write_offset_;
 370   memcpy(write, data, length);
 371   memset(write + length, 0, data_len - length);
 372   header_->payload_size = static_cast<uint32>(new_size);
 373   write_offset_ = new_size;
 374 }
 375
 376 }  // namespace base