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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 <AK/NonnullOwnPtrVector.h>
#include <LibCore/Event.h>
#include <LibCore/LocalSocket.h>
#include <LibCore/Notifier.h>
#include <LibCore/SyscallUtils.h>
#include <LibIPC/Message.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/select.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
namespace IPC {
template<typename LocalEndpoint, typename PeerEndpoint>
class ServerConnection : public Core::Object {
public:
ServerConnection(LocalEndpoint& local_endpoint, const StringView& address)
: m_local_endpoint(local_endpoint)
, m_connection(Core::LocalSocket::construct(this))
, m_notifier(Core::Notifier::construct(m_connection->fd(), Core::Notifier::Read, this))
{
// We want to rate-limit our clients
m_connection->set_blocking(true);
m_notifier->on_ready_to_read = [this] {
drain_messages_from_server();
handle_messages();
};
int retries = 100000;
while (retries) {
if (m_connection->connect(Core::SocketAddress::local(address))) {
break;
}
dbgprintf("Client::Connection: connect failed: %d, %s\n", errno, strerror(errno));
usleep(10000);
--retries;
}
ucred creds;
socklen_t creds_size = sizeof(creds);
if (getsockopt(m_connection->fd(), SOL_SOCKET, SO_PEERCRED, &creds, &creds_size) < 0) {
ASSERT_NOT_REACHED();
}
m_server_pid = creds.pid;
ASSERT(m_connection->is_connected());
}
virtual void handshake() = 0;
pid_t server_pid() const { return m_server_pid; }
void set_my_client_id(int id) { m_my_client_id = id; }
int my_client_id() const { return m_my_client_id; }
template<typename MessageType>
OwnPtr<MessageType> wait_for_specific_message()
{
// Double check we don't already have the event waiting for us.
// Otherwise we might end up blocked for a while for no reason.
for (size_t i = 0; i < m_unprocessed_messages.size(); ++i) {
if (m_unprocessed_messages[i]->message_id() == MessageType::static_message_id()) {
auto message = move(m_unprocessed_messages[i]);
m_unprocessed_messages.remove(i);
return message.template release_nonnull<MessageType>();
}
}
for (;;) {
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(m_connection->fd(), &rfds);
int rc = Core::safe_syscall(select, m_connection->fd() + 1, &rfds, nullptr, nullptr, nullptr);
if (rc < 0) {
perror("select");
}
ASSERT(rc > 0);
ASSERT(FD_ISSET(m_connection->fd(), &rfds));
if (!drain_messages_from_server())
return nullptr;
for (size_t i = 0; i < m_unprocessed_messages.size(); ++i) {
if (m_unprocessed_messages[i]->message_id() == MessageType::static_message_id()) {
auto message = move(m_unprocessed_messages[i]);
m_unprocessed_messages.remove(i);
return message.template release_nonnull<MessageType>();
}
}
}
}
bool post_message(const Message& message)
{
auto buffer = message.encode();
int nwritten = write(m_connection->fd(), buffer.data(), buffer.size());
if (nwritten < 0) {
perror("write");
ASSERT_NOT_REACHED();
return false;
}
ASSERT(static_cast<size_t>(nwritten) == buffer.size());
return true;
}
template<typename RequestType, typename... Args>
OwnPtr<typename RequestType::ResponseType> send_sync(Args&&... args)
{
bool success = post_message(RequestType(forward<Args>(args)...));
ASSERT(success);
auto response = wait_for_specific_message<typename RequestType::ResponseType>();
ASSERT(response);
return response;
}
private:
bool drain_messages_from_server()
{
Vector<u8> bytes;
for (;;) {
u8 buffer[4096];
ssize_t nread = recv(m_connection->fd(), buffer, sizeof(buffer), MSG_DONTWAIT);
if (nread < 0) {
if (errno == EAGAIN)
break;
perror("read");
exit(1);
return false;
}
if (nread == 0) {
dbg() << "EOF on IPC fd";
// FIXME: Dying is definitely not always appropriate!
exit(1);
return false;
}
bytes.append(buffer, nread);
}
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);
if (auto message = LocalEndpoint::decode_message(remaining_bytes, decoded_bytes)) {
m_unprocessed_messages.append(move(message));
} else if (auto message = PeerEndpoint::decode_message(remaining_bytes, decoded_bytes)) {
m_unprocessed_messages.append(move(message));
} else {
ASSERT_NOT_REACHED();
}
ASSERT(decoded_bytes);
}
if (!m_unprocessed_messages.is_empty()) {
deferred_invoke([this](auto&) {
handle_messages();
});
}
return true;
}
void handle_messages()
{
auto messages = move(m_unprocessed_messages);
for (auto& message : messages) {
if (message->endpoint_magic() == LocalEndpoint::static_magic())
m_local_endpoint.handle(*message);
}
}
LocalEndpoint& m_local_endpoint;
RefPtr<Core::LocalSocket> m_connection;
RefPtr<Core::Notifier> m_notifier;
Vector<OwnPtr<Message>> m_unprocessed_messages;
int m_server_pid { -1 };
int m_my_client_id { -1 };
};
}
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