mpd/src/system/EventPipe.cxx

106 lines
2.7 KiB
C++

/*
* Copyright 2003-2021 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "EventPipe.hxx"
#include "io/FileDescriptor.hxx"
#include "system/Error.hxx"
#include "util/Compiler.h"
#include <cassert>
#include <unistd.h>
#ifdef _WIN32
#include "net/IPv4Address.hxx"
#include "net/StaticSocketAddress.hxx"
#include "net/UniqueSocketDescriptor.hxx"
#include "net/SocketError.hxx"
#endif
#ifdef _WIN32
static void PoorSocketPair(UniqueSocketDescriptor &socket0,
UniqueSocketDescriptor &socket01);
#endif
EventPipe::EventPipe()
{
#ifdef _WIN32
PoorSocketPair(r, w);
#else
if (!UniqueFileDescriptor::CreatePipeNonBlock(r, w))
throw MakeErrno("pipe() has failed");
#endif
}
EventPipe::~EventPipe() noexcept = default;
bool
EventPipe::Read() noexcept
{
assert(r.IsDefined());
assert(w.IsDefined());
char buffer[256];
return r.Read(buffer, sizeof(buffer)) > 0;
}
void
EventPipe::Write() noexcept
{
assert(r.IsDefined());
assert(w.IsDefined());
w.Write("", 1);
}
#ifdef _WIN32
/* Our poor man's socketpair() implementation
* Due to limited protocol/address family support
* it's better to keep this as a private implementation detail of EventPipe
* rather than wide-available API.
*/
static void
PoorSocketPair(UniqueSocketDescriptor &socket0, UniqueSocketDescriptor &socket1)
{
UniqueSocketDescriptor listen_socket;
if (!listen_socket.Create(AF_INET, SOCK_STREAM, IPPROTO_TCP))
throw MakeSocketError("Failed to create socket");
if (!listen_socket.Bind(IPv4Address(IPv4Address::Loopback(), 0)))
throw MakeSocketError("Failed to create socket");
if (!listen_socket.Listen(1))
throw MakeSocketError("Failed to listen on socket");
if (!socket0.Create(AF_INET, SOCK_STREAM, IPPROTO_TCP))
throw MakeSocketError("Failed to create socket");
if (!socket0.Connect(listen_socket.GetLocalAddress()))
throw MakeSocketError("Failed to connect socket");
socket0.SetNonBlocking();
socket1 = listen_socket.AcceptNonBlock();
if (!socket1.IsDefined())
throw MakeSocketError("Failed to accept connection");
}
#endif