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// Copyright 2013 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 "mojo/edk/system/message_in_transit.h"
#include <string.h>
#include <ostream>
#include "base/logging.h"
#include "mojo/edk/system/configuration.h"
#include "mojo/edk/system/transport_data.h"
namespace mojo {
namespace edk {
MOJO_STATIC_CONST_MEMBER_DEFINITION const size_t
MessageInTransit::kMessageAlignment;
struct MessageInTransit::PrivateStructForCompileAsserts {
// The size of |Header| must be a multiple of the alignment.
static_assert(sizeof(Header) % kMessageAlignment == 0,
"sizeof(MessageInTransit::Header) invalid");
};
MessageInTransit::View::View(size_t message_size, const void* buffer)
: buffer_(buffer) {
size_t next_message_size = 0;
DCHECK(MessageInTransit::GetNextMessageSize(buffer_, message_size,
&next_message_size));
DCHECK_EQ(message_size, next_message_size);
// This should be equivalent.
DCHECK_EQ(message_size, total_size());
}
bool MessageInTransit::View::IsValid(size_t serialized_platform_handle_size,
const char** error_message) const {
size_t max_message_num_bytes = GetConfiguration().max_message_num_bytes;
// Avoid dangerous situations, but making sure that the size of the "header" +
// the size of the data fits into a 31-bit number.
DCHECK_LE(static_cast<uint64_t>(sizeof(Header)) + max_message_num_bytes,
0x7fffffffULL)
<< "GetConfiguration().max_message_num_bytes too big";
// We assume (to avoid extra rounding code) that the maximum message (data)
// size is a multiple of the alignment.
DCHECK_EQ(max_message_num_bytes % kMessageAlignment, 0U)
<< "GetConfiguration().max_message_num_bytes not a multiple of alignment";
// Note: This also implies a check on the |main_buffer_size()|, which is just
// |RoundUpMessageAlignment(sizeof(Header) + num_bytes())|.
if (num_bytes() > max_message_num_bytes) {
*error_message = "Message data payload too large";
return false;
}
if (transport_data_buffer_size() > 0) {
const char* e = TransportData::ValidateBuffer(
serialized_platform_handle_size, transport_data_buffer(),
transport_data_buffer_size());
if (e) {
*error_message = e;
return false;
}
}
return true;
}
MessageInTransit::MessageInTransit(Type type,
uint32_t num_bytes,
const void* bytes)
: main_buffer_size_(RoundUpMessageAlignment(sizeof(Header) + num_bytes)),
main_buffer_(static_cast<char*>(
base::AlignedAlloc(main_buffer_size_, kMessageAlignment))) {
ConstructorHelper(type, num_bytes);
if (bytes) {
memcpy(MessageInTransit::bytes(), bytes, num_bytes);
memset(static_cast<char*>(MessageInTransit::bytes()) + num_bytes, 0,
main_buffer_size_ - sizeof(Header) - num_bytes);
} else {
memset(MessageInTransit::bytes(), 0, main_buffer_size_ - sizeof(Header));
}
}
MessageInTransit::MessageInTransit(const View& message_view)
: main_buffer_size_(message_view.main_buffer_size()),
main_buffer_(static_cast<char*>(
base::AlignedAlloc(main_buffer_size_, kMessageAlignment))) {
DCHECK_GE(main_buffer_size_, sizeof(Header));
DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
memcpy(main_buffer_.get(), message_view.main_buffer(), main_buffer_size_);
DCHECK_EQ(main_buffer_size_,
RoundUpMessageAlignment(sizeof(Header) + num_bytes()));
}
MessageInTransit::~MessageInTransit() {
if (dispatchers_) {
for (size_t i = 0; i < dispatchers_->size(); i++) {
if (!(*dispatchers_)[i])
continue;
(*dispatchers_)[i]->Close();
}
}
}
// static
bool MessageInTransit::GetNextMessageSize(const void* buffer,
size_t buffer_size,
size_t* next_message_size) {
DCHECK(next_message_size);
if (!buffer_size)
return false;
DCHECK(buffer);
DCHECK_EQ(
reinterpret_cast<uintptr_t>(buffer) % MessageInTransit::kMessageAlignment,
0u);
if (buffer_size < sizeof(Header))
return false;
const Header* header = static_cast<const Header*>(buffer);
*next_message_size = header->total_size;
DCHECK_EQ(*next_message_size % kMessageAlignment, 0u);
return true;
}
void MessageInTransit::SetDispatchers(
scoped_ptr<DispatcherVector> dispatchers) {
DCHECK(dispatchers);
DCHECK(!dispatchers_);
DCHECK(!transport_data_);
dispatchers_ = dispatchers.Pass();
}
void MessageInTransit::SetTransportData(
scoped_ptr<TransportData> transport_data) {
DCHECK(transport_data);
DCHECK(!transport_data_);
DCHECK(!dispatchers_);
transport_data_ = transport_data.Pass();
UpdateTotalSize();
}
void MessageInTransit::SerializeAndCloseDispatchers() {
DCHECK(!transport_data_);
if (!dispatchers_ || !dispatchers_->size())
return;
transport_data_.reset(new TransportData(dispatchers_.Pass()));
// Update the sizes in the message header.
UpdateTotalSize();
}
void MessageInTransit::ConstructorHelper(Type type,
uint32_t num_bytes) {
DCHECK_LE(num_bytes, GetConfiguration().max_message_num_bytes);
// |total_size| is updated below, from the other values.
header()->type = type;
header()->num_bytes = num_bytes;
header()->unused = 0;
// Note: If dispatchers are subsequently attached, then |total_size| will have
// to be adjusted.
UpdateTotalSize();
}
void MessageInTransit::UpdateTotalSize() {
DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
header()->total_size = static_cast<uint32_t>(main_buffer_size_);
if (transport_data_) {
header()->total_size +=
static_cast<uint32_t>(transport_data_->buffer_size());
}
}
} // namespace edk
} // namespace mojo
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