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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/system/message_in_transit.h"
#include <string.h>
#include <new>
#include "base/compiler_specific.h"
#include "base/logging.h"
#include "base/memory/aligned_memory.h"
#include "mojo/system/constants.h"
namespace mojo {
namespace system {
struct MessageInTransit::PrivateStructForCompileAsserts {
// The size of |Header| must be appropriate to maintain alignment of the
// following data.
COMPILE_ASSERT(sizeof(Header) % kMessageAlignment == 0,
sizeof_MessageInTransit_Header_invalid);
// Avoid dangerous situations, but making sure that the size of the "header" +
// the size of the data fits into a 31-bit number.
COMPILE_ASSERT(static_cast<uint64_t>(sizeof(Header)) + kMaxMessageNumBytes <=
0x7fffffffULL,
kMaxMessageNumBytes_too_big);
// The size of |HandleTableEntry| must be appropriate to maintain alignment.
COMPILE_ASSERT(sizeof(HandleTableEntry) % kMessageAlignment == 0,
sizeof_MessageInTransit_HandleTableEntry_invalid);
};
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
MessageInTransit::kTypeMessagePipeEndpoint;
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
MessageInTransit::kTypeMessagePipe;
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Type
MessageInTransit::kTypeChannel;
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
MessageInTransit::kSubtypeMessagePipeEndpointData;
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::Subtype
MessageInTransit::kSubtypeMessagePipePeerClosed;
STATIC_CONST_MEMBER_DEFINITION const MessageInTransit::EndpointId
MessageInTransit::kInvalidEndpointId;
STATIC_CONST_MEMBER_DEFINITION const size_t MessageInTransit::kMessageAlignment;
MessageInTransit::View::View(size_t message_size, const void* buffer)
: message_size_(message_size),
buffer_(buffer) {
size_t next_message_size = 0;
DCHECK(MessageInTransit::GetNextMessageSize(buffer_, message_size_,
&next_message_size));
DCHECK_EQ(message_size_, next_message_size);
}
MessageInTransit::MessageInTransit(Type type,
Subtype subtype,
uint32_t num_bytes,
uint32_t num_handles,
const void* bytes)
: main_buffer_size_(RoundUpMessageAlignment(sizeof(Header) + num_bytes)),
main_buffer_(base::AlignedAlloc(main_buffer_size_, kMessageAlignment)),
secondary_buffer_size_(0),
secondary_buffer_(NULL) {
DCHECK_LE(num_bytes, kMaxMessageNumBytes);
DCHECK_LE(num_handles, kMaxMessageNumHandles);
// |total_size| is updated below, from the other values.
header()->type = type;
header()->subtype = subtype;
header()->source_id = kInvalidEndpointId;
header()->destination_id = kInvalidEndpointId;
header()->num_bytes = num_bytes;
header()->num_handles = num_handles;
// Note: If dispatchers are subsequently attached (in particular, if
// |num_handles| is nonzero), then |total_size| will have to be adjusted.
UpdateTotalSize();
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_(base::AlignedAlloc(main_buffer_size_, kMessageAlignment)),
secondary_buffer_size_(message_view.secondary_buffer_size()),
secondary_buffer_(secondary_buffer_size_ ?
base::AlignedAlloc(secondary_buffer_size_,
kMessageAlignment) : NULL) {
DCHECK_GE(main_buffer_size_, sizeof(Header));
DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
memcpy(main_buffer_, message_view.main_buffer(), main_buffer_size_);
memcpy(secondary_buffer_, message_view.secondary_buffer(),
secondary_buffer_size_);
DCHECK_EQ(main_buffer_size_,
RoundUpMessageAlignment(sizeof(Header) + num_bytes()));
}
MessageInTransit::~MessageInTransit() {
base::AlignedFree(main_buffer_);
base::AlignedFree(secondary_buffer_); // Okay if null.
#ifndef NDEBUG
main_buffer_size_ = 0;
main_buffer_ = NULL;
secondary_buffer_size_ = 0;
secondary_buffer_ = NULL;
#endif
if (dispatchers_.get()) {
for (size_t i = 0; i < dispatchers_->size(); i++) {
if (!(*dispatchers_)[i])
continue;
DCHECK((*dispatchers_)[i]->HasOneRef());
(*dispatchers_)[i]->Close();
}
dispatchers_.reset();
}
}
// static
bool MessageInTransit::GetNextMessageSize(const void* buffer,
size_t buffer_size,
size_t* next_message_size) {
DCHECK(buffer);
DCHECK_EQ(reinterpret_cast<uintptr_t>(buffer) %
MessageInTransit::kMessageAlignment, 0u);
DCHECK(next_message_size);
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<std::vector<scoped_refptr<Dispatcher> > > dispatchers) {
DCHECK(dispatchers.get());
DCHECK(!dispatchers_.get());
dispatchers_ = dispatchers.Pass();
#ifndef NDEBUG
for (size_t i = 0; i < dispatchers_->size(); i++)
DCHECK(!(*dispatchers_)[i] || (*dispatchers_)[i]->HasOneRef());
#endif
}
void MessageInTransit::SerializeAndCloseDispatchers(Channel* channel) {
DCHECK(channel);
DCHECK(!secondary_buffer_);
CHECK_EQ(num_handles(),
dispatchers_.get() ? dispatchers_->size() : static_cast<size_t>(0));
if (!num_handles())
return;
size_t handle_table_size = num_handles() * sizeof(HandleTableEntry);
// The size of the secondary buffer. We'll start with the size of the handle
// table, and add to it as we go along.
size_t size = handle_table_size;
for (size_t i = 0; i < dispatchers_->size(); i++) {
if (Dispatcher* dispatcher = (*dispatchers_)[i]) {
size += RoundUpMessageAlignment(
Dispatcher::MessageInTransitAccess::GetMaximumSerializedSize(
dispatcher, channel));
// TODO(vtl): Check for overflow?
}
}
secondary_buffer_ = base::AlignedAlloc(size, kMessageAlignment);
// TODO(vtl): Check for overflow?
secondary_buffer_size_ = static_cast<uint32_t>(size);
// Entirely clear out the secondary buffer, since then we won't have to worry
// about clearing padding or unused space (e.g., if a dispatcher fails to
// serialize).
memset(secondary_buffer_, 0, size);
HandleTableEntry* handle_table =
static_cast<HandleTableEntry*>(secondary_buffer_);
size_t current_offset = handle_table_size;
for (size_t i = 0; i < dispatchers_->size(); i++) {
Dispatcher* dispatcher = (*dispatchers_)[i];
if (!dispatcher) {
COMPILE_ASSERT(Dispatcher::kTypeUnknown == 0,
need_Dispatcher_kTypeUnknown_to_be_zero);
continue;
}
size_t actual_size = 0;
if (Dispatcher::MessageInTransitAccess::SerializeAndClose(
dispatcher, static_cast<char*>(secondary_buffer_) + current_offset,
channel, &actual_size)) {
handle_table[i].type = static_cast<int32_t>(dispatcher->GetType());
handle_table[i].offset = static_cast<uint32_t>(current_offset);
handle_table[i].size = static_cast<uint32_t>(actual_size);
}
// (Nothing to do on failure, since |secondary_buffer_| was cleared, and
// |kTypeUnknown| is zero.)
current_offset += RoundUpMessageAlignment(actual_size);
DCHECK_LE(current_offset, size);
}
UpdateTotalSize();
}
void MessageInTransit::UpdateTotalSize() {
DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
DCHECK_EQ(secondary_buffer_size_ % kMessageAlignment, 0u);
header()->total_size =
static_cast<uint32_t>(main_buffer_size_ + secondary_buffer_size_);
}
} // namespace system
} // namespace mojo
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