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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 "ipc/ipc_channel_reader.h"
#include <stddef.h>
#include <algorithm>
#include "base/logging.h"
#include "base/threading/thread_task_runner_handle.h"
#include "ipc/ipc_listener.h"
#include "ipc/ipc_logging.h"
#include "ipc/ipc_message.h"
#include "ipc/ipc_message_attachment_set.h"
#include "ipc/ipc_message_macros.h"
namespace IPC {
namespace internal {
#if BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
namespace {
std::string GetMessageText(const Message& message) {
std::string name;
Logging::GetInstance()->GetMessageText(
message.type(), &name, &message, nullptr);
return name;
}
} // namespace
#define EMIT_TRACE_EVENT(message) \
TRACE_EVENT_WITH_FLOW1( \
"ipc,toplevel", "ChannelReader::DispatchInputData", \
(message).flags(), TRACE_EVENT_FLAG_FLOW_IN, "name", \
GetMessageText(message));
#else
#define EMIT_TRACE_EVENT(message) \
TRACE_EVENT_WITH_FLOW2("ipc,toplevel", "ChannelReader::DispatchInputData", \
(message).flags(), TRACE_EVENT_FLAG_FLOW_IN, "class", \
IPC_MESSAGE_ID_CLASS((message).type()), "line", \
IPC_MESSAGE_ID_LINE((message).type()));
#endif // BUILDFLAG(IPC_MESSAGE_LOG_ENABLED)
ChannelReader::ChannelReader(Listener* listener)
: listener_(listener),
max_input_buffer_size_(Channel::kMaximumReadBufferSize) {
memset(input_buf_, 0, sizeof(input_buf_));
}
ChannelReader::~ChannelReader() = default;
ChannelReader::DispatchState ChannelReader::ProcessIncomingMessages() {
while (true) {
int bytes_read = 0;
ReadState read_state = ReadData(input_buf_, Channel::kReadBufferSize,
&bytes_read);
if (read_state == READ_FAILED)
return DISPATCH_ERROR;
if (read_state == READ_PENDING)
return DISPATCH_FINISHED;
DCHECK(bytes_read > 0);
if (!TranslateInputData(input_buf_, bytes_read))
return DISPATCH_ERROR;
}
}
ChannelReader::DispatchState ChannelReader::AsyncReadComplete(int bytes_read) {
if (!TranslateInputData(input_buf_, bytes_read))
return DISPATCH_ERROR;
return DISPATCH_FINISHED;
}
bool ChannelReader::IsInternalMessage(const Message& m) {
return m.routing_id() == MSG_ROUTING_NONE &&
m.type() >= Channel::CLOSE_FD_MESSAGE_TYPE &&
m.type() <= Channel::HELLO_MESSAGE_TYPE;
}
bool ChannelReader::IsHelloMessage(const Message& m) {
return m.routing_id() == MSG_ROUTING_NONE &&
m.type() == Channel::HELLO_MESSAGE_TYPE;
}
void ChannelReader::CleanUp() {
}
void ChannelReader::DispatchMessage(Message* m) {
EMIT_TRACE_EVENT(*m);
listener_->OnMessageReceived(*m);
HandleDispatchError(*m);
}
bool ChannelReader::TranslateInputData(const char* input_data,
int input_data_len) {
const char* p;
const char* end;
// Possibly combine with the overflow buffer to make a larger buffer.
if (input_overflow_buf_.empty()) {
p = input_data;
end = input_data + input_data_len;
} else {
if (!CheckMessageSize(input_overflow_buf_.size() + input_data_len))
return false;
input_overflow_buf_.append(input_data, input_data_len);
p = input_overflow_buf_.data();
end = p + input_overflow_buf_.size();
}
size_t next_message_size = 0;
// Dispatch all complete messages in the data buffer.
while (p < end) {
Message::NextMessageInfo info;
Message::FindNext(p, end, &info);
if (info.message_found) {
int pickle_len = static_cast<int>(info.pickle_end - p);
Message translated_message(p, pickle_len);
if (!HandleTranslatedMessage(&translated_message))
return false;
p = info.message_end;
} else {
// Last message is partial.
next_message_size = info.message_size;
if (!CheckMessageSize(next_message_size))
return false;
break;
}
}
// Account for the case where last message's byte is in the next data chunk.
size_t next_message_buffer_size = next_message_size ?
next_message_size + Channel::kReadBufferSize - 1:
0;
// Save any partial data in the overflow buffer.
if (p != input_overflow_buf_.data())
input_overflow_buf_.assign(p, end - p);
if (!input_overflow_buf_.empty()) {
// We have something in the overflow buffer, which means that we will
// append the next data chunk (instead of parsing it directly). So we
// resize the buffer to fit the next message, to avoid repeatedly
// growing the buffer as we receive all message' data chunks.
if (next_message_buffer_size > input_overflow_buf_.capacity()) {
input_overflow_buf_.reserve(next_message_buffer_size);
}
}
// Trim the buffer if we can
if (next_message_buffer_size < max_input_buffer_size_ &&
input_overflow_buf_.size() < max_input_buffer_size_ &&
input_overflow_buf_.capacity() > max_input_buffer_size_) {
// std::string doesn't really have a method to shrink capacity to
// a specific value, so we have to swap with another string.
std::string trimmed_buf;
trimmed_buf.reserve(max_input_buffer_size_);
if (trimmed_buf.capacity() > max_input_buffer_size_) {
// Since we don't control how much space reserve() actually reserves,
// we have to go other way around and change the max size to avoid
// getting into the outer if() again.
max_input_buffer_size_ = trimmed_buf.capacity();
}
trimmed_buf.assign(input_overflow_buf_.data(),
input_overflow_buf_.size());
input_overflow_buf_.swap(trimmed_buf);
}
if (input_overflow_buf_.empty() && !DidEmptyInputBuffers())
return false;
return true;
}
bool ChannelReader::HandleTranslatedMessage(Message* translated_message) {
// Immediately handle internal messages.
if (IsInternalMessage(*translated_message)) {
EMIT_TRACE_EVENT(*translated_message);
HandleInternalMessage(*translated_message);
HandleDispatchError(*translated_message);
return true;
}
return HandleExternalMessage(translated_message);
}
bool ChannelReader::HandleExternalMessage(Message* external_message) {
if (!GetAttachments(external_message))
return false;
DispatchMessage(external_message);
return true;
}
void ChannelReader::HandleDispatchError(const Message& message) {
if (message.dispatch_error())
listener_->OnBadMessageReceived(message);
}
bool ChannelReader::CheckMessageSize(size_t size) {
if (size <= Channel::kMaximumMessageSize) {
return true;
}
input_overflow_buf_.clear();
LOG(ERROR) << "IPC message is too big: " << size;
return false;
}
} // namespace internal
} // namespace IPC
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