mpd/src/Listen.cxx

165 lines
4.1 KiB
C++

/*
* Copyright 2003-2022 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 "config.h"
#include "Listen.hxx"
#include "Log.hxx"
#include "client/Listener.hxx"
#include "config/Param.hxx"
#include "config/Data.hxx"
#include "config/Option.hxx"
#include "config/Net.hxx"
#include "lib/fmt/ExceptionFormatter.hxx"
#include "lib/fmt/PathFormatter.hxx"
#include "net/AllocatedSocketAddress.hxx"
#include "net/UniqueSocketDescriptor.hxx"
#include "net/SocketUtil.hxx"
#include "system/Error.hxx"
#include "fs/AllocatedPath.hxx"
#include "fs/StandardDirectory.hxx"
#include "fs/XDG.hxx"
#include "util/Domain.hxx"
#include "util/RuntimeError.hxx"
#include <sys/stat.h>
#ifdef ENABLE_SYSTEMD_DAEMON
#include <systemd/sd-daemon.h>
#endif
#define DEFAULT_PORT 6600
#if defined(USE_XDG) && defined(HAVE_UN)
static constexpr Domain listen_domain("listen");
#endif
int listen_port;
#ifdef ENABLE_SYSTEMD_DAEMON
static bool
listen_systemd_activation(ClientListener &listener)
{
int n = sd_listen_fds(true);
if (n <= 0) {
if (n < 0)
throw MakeErrno(-n, "sd_listen_fds() failed");
return false;
}
for (int i = SD_LISTEN_FDS_START, end = SD_LISTEN_FDS_START + n;
i != end; ++i)
listener.AddFD(UniqueSocketDescriptor(i));
return true;
}
#endif
/**
* Listen on "$XDG_RUNTIME_DIR/mpd/socket" (if applicable).
*
* @return true if a listener socket was added
*/
static bool
ListenXdgRuntimeDir(ClientListener &listener) noexcept
{
#if defined(USE_XDG) && defined(HAVE_UN)
if (geteuid() == 0)
/* this MPD instance is a system-wide daemon; don't
use $XDG_RUNTIME_DIR */
return false;
const auto mpd_runtime_dir = GetAppRuntimeDir();
if (mpd_runtime_dir.IsNull())
return false;
const auto socket_path = mpd_runtime_dir / Path::FromFS("socket");
unlink(socket_path.c_str());
AllocatedSocketAddress address;
address.SetLocal(socket_path.c_str());
try {
auto fd = socket_bind_listen(AF_LOCAL, SOCK_STREAM, 0,
address, 5);
chmod(socket_path.c_str(), 0600);
listener.AddFD(std::move(fd), std::move(address));
return true;
} catch (...) {
FmtError(listen_domain,
"Failed to listen on '{}' (not fatal): {}",
socket_path, std::current_exception());
return false;
}
#else
(void)listener;
return false;
#endif
}
void
listen_global_init(const ConfigData &config, ClientListener &listener)
{
int port = config.GetPositive(ConfigOption::PORT, DEFAULT_PORT);
#ifdef ENABLE_SYSTEMD_DAEMON
if (listen_systemd_activation(listener))
return;
#endif
for (const auto &param : config.GetParamList(ConfigOption::BIND_TO_ADDRESS)) {
try {
ServerSocketAddGeneric(listener, param.value.c_str(),
port);
} catch (...) {
std::throw_with_nested(FormatRuntimeError("Failed to listen on %s (line %i)",
param.value.c_str(),
param.line));
}
}
bool have_xdg_runtime_listener = false;
if (listener.IsEmpty()) {
/* no "bind_to_address" configured, bind the
configured port on all interfaces */
have_xdg_runtime_listener = ListenXdgRuntimeDir(listener);
try {
listener.AddPort(port);
} catch (...) {
std::throw_with_nested(FormatRuntimeError("Failed to listen on *:%d: ", port));
}
}
try {
listener.Open();
} catch (...) {
if (have_xdg_runtime_listener)
LogError(std::current_exception(),
"Default TCP listener setup failed, but this is okay because we have a $XDG_RUNTIME_DIR listener");
else
throw;
}
listen_port = port;
}