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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/ByteBuffer.h>
#include <LibCore/Event.h>
#include <LibCore/EventLoop.h>
#include <LibCore/LocalSocket.h>
#include <LibCore/Object.h>
#include <LibCore/Timer.h>
#include <LibIPC/Endpoint.h>
#include <LibIPC/Message.h>
#include <errno.h>
#include <stdio.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
namespace IPC {
class Event : public Core::Event {
public:
enum Type {
Invalid = 2000,
Disconnected,
};
Event() {}
explicit Event(Type type)
: Core::Event(type)
{
}
};
class DisconnectedEvent : public Event {
public:
explicit DisconnectedEvent(int client_id)
: Event(Disconnected)
, m_client_id(client_id)
{
}
int client_id() const { return m_client_id; }
private:
int m_client_id { 0 };
};
template<typename T, class... Args>
NonnullRefPtr<T> new_client_connection(Args&&... args)
{
return T::construct(forward<Args>(args)...) /* arghs */;
}
template<typename Endpoint>
class ClientConnection : public Core::Object {
public:
ClientConnection(Endpoint& endpoint, Core::LocalSocket& socket, int client_id)
: m_endpoint(endpoint)
, m_socket(socket)
, m_client_id(client_id)
{
ASSERT(socket.is_connected());
ucred creds;
socklen_t creds_size = sizeof(creds);
if (getsockopt(m_socket->fd(), SOL_SOCKET, SO_PEERCRED, &creds, &creds_size) < 0) {
ASSERT_NOT_REACHED();
}
m_client_pid = creds.pid;
add_child(socket);
m_socket->on_ready_to_read = [this] { drain_messages_from_client(); };
m_responsiveness_timer = Core::Timer::create_single_shot(3000, [this] { may_have_become_unresponsive(); });
}
virtual ~ClientConnection() override
{
}
virtual void may_have_become_unresponsive() {}
virtual void did_become_responsive() {}
void post_message(const Message& message)
{
// NOTE: If this connection is being shut down, but has not yet been destroyed,
// the socket will be closed. Don't try to send more messages.
if (!m_socket->is_open())
return;
auto buffer = message.encode();
int nwritten = write(m_socket->fd(), buffer.data(), buffer.size());
if (nwritten < 0) {
switch (errno) {
case EPIPE:
dbg() << *this << "::post_message: Disconnected from peer";
shutdown();
return;
case EAGAIN:
dbg() << *this << "::post_message: Client buffer overflowed.";
did_misbehave();
return;
default:
perror("Connection::post_message write");
shutdown();
return;
}
}
ASSERT(static_cast<size_t>(nwritten) == buffer.size());
m_responsiveness_timer->start();
}
void drain_messages_from_client()
{
if (!m_socket->is_open())
return;
Vector<u8> bytes;
for (;;) {
u8 buffer[4096];
ssize_t nread = recv(m_socket->fd(), buffer, sizeof(buffer), MSG_DONTWAIT);
if (nread == 0 || (nread == -1 && errno == EAGAIN)) {
if (bytes.is_empty()) {
Core::EventLoop::current().post_event(*this, make<DisconnectedEvent>(client_id()));
return;
}
break;
}
if (nread < 0) {
perror("recv");
shutdown();
return;
}
bytes.append(buffer, nread);
}
if (!bytes.is_empty()) {
m_responsiveness_timer->stop();
did_become_responsive();
}
size_t decoded_bytes = 0;
for (size_t index = 0; index < bytes.size(); index += decoded_bytes) {
auto remaining_bytes = ByteBuffer::wrap(bytes.data() + index, bytes.size() - index);
auto message = Endpoint::decode_message(remaining_bytes, decoded_bytes);
if (!message) {
dbg() << "drain_messages_from_client: Endpoint didn't recognize message";
did_misbehave();
return;
}
if (auto response = m_endpoint.handle(*message))
post_message(*response);
ASSERT(decoded_bytes);
}
}
void did_misbehave()
{
dbg() << *this << " (id=" << m_client_id << ", pid=" << m_client_pid << ") misbehaved, disconnecting.";
shutdown();
}
void did_misbehave(const char* message)
{
dbg() << *this << " (id=" << m_client_id << ", pid=" << m_client_pid << ") misbehaved (" << message << "), disconnecting.";
shutdown();
}
void shutdown()
{
m_socket->close();
die();
}
int client_id() const { return m_client_id; }
pid_t client_pid() const { return m_client_pid; }
virtual void die() = 0;
protected:
void event(Core::Event& event) override
{
if (event.type() == Event::Disconnected) {
int client_id = static_cast<const DisconnectedEvent&>(event).client_id();
dbg() << *this << ": Client disconnected: " << client_id;
die();
return;
}
Core::Object::event(event);
}
private:
Endpoint& m_endpoint;
RefPtr<Core::LocalSocket> m_socket;
RefPtr<Core::Timer> m_responsiveness_timer;
int m_client_id { -1 };
int m_client_pid { -1 };
};
}
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