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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/pickle.h"
#include <stdlib.h>
#include <algorithm> // for max()
#include <limits>
#include "base/bits.h"
#include "base/numerics/safe_conversions.h"
#include "base/numerics/safe_math.h"
#include "build/build_config.h"
namespace base {
// static
const int Pickle::kPayloadUnit = 64;
static const size_t kCapacityReadOnly = static_cast<size_t>(-1);
PickleIterator::PickleIterator(const Pickle& pickle)
: payload_(pickle.payload()),
read_index_(0),
end_index_(pickle.payload_size()) {
}
template <typename Type>
inline bool PickleIterator::ReadBuiltinType(Type* result) {
const char* read_from = GetReadPointerAndAdvance<Type>();
if (!read_from)
return false;
if (sizeof(Type) > sizeof(uint32_t))
memcpy(result, read_from, sizeof(*result));
else
*result = *reinterpret_cast<const Type*>(read_from);
return true;
}
inline void PickleIterator::Advance(size_t size) {
size_t aligned_size = bits::AlignUp(size, sizeof(uint32_t));
if (end_index_ - read_index_ < aligned_size) {
read_index_ = end_index_;
} else {
read_index_ += aligned_size;
}
}
template<typename Type>
inline const char* PickleIterator::GetReadPointerAndAdvance() {
if (sizeof(Type) > end_index_ - read_index_) {
read_index_ = end_index_;
return nullptr;
}
const char* current_read_ptr = payload_ + read_index_;
Advance(sizeof(Type));
return current_read_ptr;
}
const char* PickleIterator::GetReadPointerAndAdvance(int num_bytes) {
if (num_bytes < 0 ||
end_index_ - read_index_ < static_cast<size_t>(num_bytes)) {
read_index_ = end_index_;
return nullptr;
}
const char* current_read_ptr = payload_ + read_index_;
Advance(num_bytes);
return current_read_ptr;
}
inline const char* PickleIterator::GetReadPointerAndAdvance(
int num_elements,
size_t size_element) {
// Check for int32_t overflow.
int num_bytes;
if (!CheckMul(num_elements, size_element).AssignIfValid(&num_bytes))
return nullptr;
return GetReadPointerAndAdvance(num_bytes);
}
bool PickleIterator::ReadBool(bool* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadInt(int* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadLong(long* result) {
// Always read long as a 64-bit value to ensure compatibility between 32-bit
// and 64-bit processes.
int64_t result_int64 = 0;
if (!ReadBuiltinType(&result_int64))
return false;
// CHECK if the cast truncates the value so that we know to change this IPC
// parameter to use int64_t.
*result = base::checked_cast<long>(result_int64);
return true;
}
bool PickleIterator::ReadUInt16(uint16_t* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadUInt32(uint32_t* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadInt64(int64_t* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadUInt64(uint64_t* result) {
return ReadBuiltinType(result);
}
bool PickleIterator::ReadFloat(float* result) {
// crbug.com/315213
// The source data may not be properly aligned, and unaligned float reads
// cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
// into the result.
const char* read_from = GetReadPointerAndAdvance<float>();
if (!read_from)
return false;
memcpy(result, read_from, sizeof(*result));
return true;
}
bool PickleIterator::ReadDouble(double* result) {
// crbug.com/315213
// The source data may not be properly aligned, and unaligned double reads
// cause SIGBUS on some ARM platforms, so force using memcpy to copy the data
// into the result.
const char* read_from = GetReadPointerAndAdvance<double>();
if (!read_from)
return false;
memcpy(result, read_from, sizeof(*result));
return true;
}
bool PickleIterator::ReadString(std::string* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len);
if (!read_from)
return false;
result->assign(read_from, len);
return true;
}
bool PickleIterator::ReadStringPiece(StringPiece* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len);
if (!read_from)
return false;
*result = StringPiece(read_from, len);
return true;
}
bool PickleIterator::ReadString16(std::u16string* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16_t));
if (!read_from)
return false;
result->assign(reinterpret_cast<const char16_t*>(read_from), len);
return true;
}
bool PickleIterator::ReadStringPiece16(StringPiece16* result) {
int len;
if (!ReadInt(&len))
return false;
const char* read_from = GetReadPointerAndAdvance(len, sizeof(char16_t));
if (!read_from)
return false;
*result = StringPiece16(reinterpret_cast<const char16_t*>(read_from), len);
return true;
}
bool PickleIterator::ReadData(const char** data, int* length) {
*length = 0;
*data = nullptr;
if (!ReadInt(length))
return false;
return ReadBytes(data, *length);
}
bool PickleIterator::ReadData(base::span<const uint8_t>* data) {
const char* ptr;
int length;
if (!ReadData(&ptr, &length))
return false;
*data = base::as_bytes(base::make_span(ptr, length));
return true;
}
bool PickleIterator::ReadBytes(const char** data, int length) {
const char* read_from = GetReadPointerAndAdvance(length);
if (!read_from)
return false;
*data = read_from;
return true;
}
Pickle::Attachment::Attachment() = default;
Pickle::Attachment::~Attachment() = default;
// Payload is uint32_t aligned.
Pickle::Pickle()
: header_(nullptr),
header_size_(sizeof(Header)),
capacity_after_header_(0),
write_offset_(0) {
static_assert(base::bits::IsPowerOfTwo(Pickle::kPayloadUnit),
"Pickle::kPayloadUnit must be a power of two");
Resize(kPayloadUnit);
header_->payload_size = 0;
}
Pickle::Pickle(int header_size)
: header_(nullptr),
header_size_(bits::AlignUp(header_size, sizeof(uint32_t))),
capacity_after_header_(0),
write_offset_(0) {
DCHECK_GE(static_cast<size_t>(header_size), sizeof(Header));
DCHECK_LE(header_size, kPayloadUnit);
Resize(kPayloadUnit);
header_->payload_size = 0;
}
Pickle::Pickle(const char* data, size_t data_len)
: header_(reinterpret_cast<Header*>(const_cast<char*>(data))),
header_size_(0),
capacity_after_header_(kCapacityReadOnly),
write_offset_(0) {
if (data_len >= static_cast<int>(sizeof(Header)))
header_size_ = data_len - header_->payload_size;
if (header_size_ > static_cast<unsigned int>(data_len))
header_size_ = 0;
if (header_size_ != bits::AlignUp(header_size_, sizeof(uint32_t)))
header_size_ = 0;
// If there is anything wrong with the data, we're not going to use it.
if (!header_size_)
header_ = nullptr;
}
Pickle::Pickle(const Pickle& other)
: header_(nullptr),
header_size_(other.header_size_),
capacity_after_header_(0),
write_offset_(other.write_offset_) {
Resize(other.header_->payload_size);
memcpy(header_, other.header_, header_size_ + other.header_->payload_size);
}
Pickle::~Pickle() {
if (capacity_after_header_ != kCapacityReadOnly)
free(header_);
}
Pickle& Pickle::operator=(const Pickle& other) {
if (this == &other) {
return *this;
}
if (capacity_after_header_ == kCapacityReadOnly) {
header_ = nullptr;
capacity_after_header_ = 0;
}
if (header_size_ != other.header_size_) {
free(header_);
header_ = nullptr;
header_size_ = other.header_size_;
}
Resize(other.header_->payload_size);
memcpy(header_, other.header_,
other.header_size_ + other.header_->payload_size);
write_offset_ = other.write_offset_;
return *this;
}
void Pickle::WriteString(const StringPiece& value) {
WriteInt(static_cast<int>(value.size()));
WriteBytes(value.data(), static_cast<int>(value.size()));
}
void Pickle::WriteString16(const StringPiece16& value) {
WriteInt(static_cast<int>(value.size()));
WriteBytes(value.data(), static_cast<int>(value.size()) * sizeof(char16_t));
}
void Pickle::WriteData(const char* data, int length) {
DCHECK_GE(length, 0);
WriteInt(length);
WriteBytes(data, length);
}
void Pickle::WriteBytes(const void* data, int length) {
WriteBytesCommon(data, length);
}
void Pickle::Reserve(size_t length) {
size_t data_len = bits::AlignUp(length, sizeof(uint32_t));
DCHECK_GE(data_len, length);
#ifdef ARCH_CPU_64_BITS
DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
#endif
DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
size_t new_size = write_offset_ + data_len;
if (new_size > capacity_after_header_)
Resize(capacity_after_header_ * 2 + new_size);
}
bool Pickle::WriteAttachment(scoped_refptr<Attachment> attachment) {
return false;
}
bool Pickle::ReadAttachment(base::PickleIterator* iter,
scoped_refptr<Attachment>* attachment) const {
return false;
}
bool Pickle::HasAttachments() const {
return false;
}
void Pickle::Resize(size_t new_capacity) {
CHECK_NE(capacity_after_header_, kCapacityReadOnly);
capacity_after_header_ = bits::AlignUp(new_capacity, kPayloadUnit);
void* p = realloc(header_, GetTotalAllocatedSize());
CHECK(p);
header_ = reinterpret_cast<Header*>(p);
}
void* Pickle::ClaimBytes(size_t num_bytes) {
void* p = ClaimUninitializedBytesInternal(num_bytes);
CHECK(p);
memset(p, 0, num_bytes);
return p;
}
size_t Pickle::GetTotalAllocatedSize() const {
if (capacity_after_header_ == kCapacityReadOnly)
return 0;
return header_size_ + capacity_after_header_;
}
// static
const char* Pickle::FindNext(size_t header_size,
const char* start,
const char* end) {
size_t pickle_size = 0;
if (!PeekNext(header_size, start, end, &pickle_size))
return nullptr;
if (pickle_size > static_cast<size_t>(end - start))
return nullptr;
return start + pickle_size;
}
// static
bool Pickle::PeekNext(size_t header_size,
const char* start,
const char* end,
size_t* pickle_size) {
DCHECK_EQ(header_size, bits::AlignUp(header_size, sizeof(uint32_t)));
DCHECK_GE(header_size, sizeof(Header));
DCHECK_LE(header_size, static_cast<size_t>(kPayloadUnit));
size_t length = static_cast<size_t>(end - start);
if (length < sizeof(Header))
return false;
const Header* hdr = reinterpret_cast<const Header*>(start);
if (length < header_size)
return false;
// If payload_size causes an overflow, we return maximum possible
// pickle size to indicate that.
*pickle_size = ClampAdd(header_size, hdr->payload_size);
return true;
}
template <size_t length> void Pickle::WriteBytesStatic(const void* data) {
WriteBytesCommon(data, length);
}
template void Pickle::WriteBytesStatic<2>(const void* data);
template void Pickle::WriteBytesStatic<4>(const void* data);
template void Pickle::WriteBytesStatic<8>(const void* data);
inline void* Pickle::ClaimUninitializedBytesInternal(size_t length) {
DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
<< "oops: pickle is readonly";
size_t data_len = bits::AlignUp(length, sizeof(uint32_t));
DCHECK_GE(data_len, length);
#ifdef ARCH_CPU_64_BITS
DCHECK_LE(data_len, std::numeric_limits<uint32_t>::max());
#endif
DCHECK_LE(write_offset_, std::numeric_limits<uint32_t>::max() - data_len);
size_t new_size = write_offset_ + data_len;
if (new_size > capacity_after_header_) {
size_t new_capacity = capacity_after_header_ * 2;
const size_t kPickleHeapAlign = 4096;
if (new_capacity > kPickleHeapAlign) {
new_capacity =
bits::AlignUp(new_capacity, kPickleHeapAlign) - kPayloadUnit;
}
Resize(std::max(new_capacity, new_size));
}
char* write = mutable_payload() + write_offset_;
memset(write + length, 0, data_len - length); // Always initialize padding
header_->payload_size = static_cast<uint32_t>(new_size);
write_offset_ = new_size;
return write;
}
inline void Pickle::WriteBytesCommon(const void* data, size_t length) {
DCHECK_NE(kCapacityReadOnly, capacity_after_header_)
<< "oops: pickle is readonly";
MSAN_CHECK_MEM_IS_INITIALIZED(data, length);
void* write = ClaimUninitializedBytesInternal(length);
memcpy(write, data, length);
}
} // namespace base