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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_not_a_multiple_of_alignment);
// 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);
};
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::MessageInTransit(OwnedBuffer,
Type type,
Subtype subtype,
uint32_t num_bytes,
uint32_t num_handles,
const void* bytes)
: owns_buffers_(true),
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;
header()->reserved0 = 0;
header()->reserved1 = 0;
// 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(OwnedBuffer,
const MessageInTransit& other)
: owns_buffers_(true),
main_buffer_size_(other.main_buffer_size()),
main_buffer_(base::AlignedAlloc(main_buffer_size_, kMessageAlignment)),
secondary_buffer_size_(other.secondary_buffer_size()),
secondary_buffer_(secondary_buffer_size_ ?
base::AlignedAlloc(secondary_buffer_size_,
kMessageAlignment) : NULL) {
DCHECK(!other.dispatchers_.get());
DCHECK_GE(main_buffer_size_, sizeof(Header));
DCHECK_EQ(main_buffer_size_ % kMessageAlignment, 0u);
memcpy(main_buffer_, other.main_buffer(), main_buffer_size_);
memcpy(secondary_buffer_, other.secondary_buffer(), secondary_buffer_size_);
DCHECK_EQ(main_buffer_size_,
RoundUpMessageAlignment(sizeof(Header) + num_bytes()));
}
MessageInTransit::MessageInTransit(UnownedBuffer,
size_t message_size,
void* buffer)
: owns_buffers_(false),
main_buffer_size_(0),
main_buffer_(NULL),
secondary_buffer_size_(0),
secondary_buffer_(NULL) {
DCHECK_GE(message_size, sizeof(Header));
DCHECK_EQ(message_size % kMessageAlignment, 0u);
DCHECK(buffer);
Header* header = static_cast<Header*>(buffer);
DCHECK_EQ(header->total_size, message_size);
main_buffer_size_ =
RoundUpMessageAlignment(sizeof(Header) + header->num_bytes);
DCHECK_LE(main_buffer_size_, message_size);
main_buffer_ = buffer;
DCHECK_EQ(reinterpret_cast<uintptr_t>(main_buffer_) % kMessageAlignment, 0u);
if (message_size > main_buffer_size_) {
secondary_buffer_size_ = message_size - main_buffer_size_;
secondary_buffer_ = static_cast<char*>(buffer) + main_buffer_size_;
DCHECK_EQ(reinterpret_cast<uintptr_t>(secondary_buffer_) %
kMessageAlignment, 0u);
}
}
MessageInTransit::~MessageInTransit() {
if (owns_buffers_) {
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(owns_buffers_);
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(owns_buffers_);
DCHECK(!secondary_buffer_);
CHECK_EQ(num_handles(),
dispatchers_.get() ? dispatchers_->size() : static_cast<size_t>(0));
if (!num_handles())
return;
// The size of the secondary buffer. We'll start with the size of the entry
// size table (which will contain the size of the data for each handle), and
// add to it as we go along.
size_t size = RoundUpMessageAlignment(num_handles() * sizeof(uint32_t));
// The maximum size that we'll need for the secondary buffer. We'll allocate
// this much.
size_t max_size = size;
// TODO(vtl): Iterate through dispatchers and query their maximum size (and
// add each, rounded up, to |max_size|).
secondary_buffer_ = base::AlignedAlloc(max_size, kMessageAlignment);
// TODO(vtl): I wonder if it's faster to clear everything once, or to only
// clear padding as needed.
memset(secondary_buffer_, 0, max_size);
uint32_t* entry_size_table = static_cast<uint32_t*>(secondary_buffer_);
for (size_t i = 0; i < dispatchers_->size(); i++) {
// The entry size table entry is already zero by default.
if (!(*dispatchers_)[i])
continue;
// TODO(vtl): Serialize this dispatcher (getting its actual size, and adding
// that (rounded up) to |size|.
entry_size_table[i] = 0;
DCHECK((*dispatchers_)[i]->HasOneRef());
(*dispatchers_)[i]->Close();
}
secondary_buffer_size_ = static_cast<uint32_t>(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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