mpd/src/event/ServerSocket.cxx

398 lines
7.9 KiB
C++

/*
* Copyright 2003-2017 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 "ServerSocket.hxx"
#include "net/IPv4Address.hxx"
#include "net/StaticSocketAddress.hxx"
#include "net/AllocatedSocketAddress.hxx"
#include "net/SocketAddress.hxx"
#include "net/SocketUtil.hxx"
#include "net/SocketError.hxx"
#include "net/UniqueSocketDescriptor.hxx"
#include "net/Resolver.hxx"
#include "net/ToString.hxx"
#include "event/SocketMonitor.hxx"
#include "fs/AllocatedPath.hxx"
#include "fs/FileSystem.hxx"
#include "util/RuntimeError.hxx"
#include "util/Domain.hxx"
#include "util/ScopeExit.hxx"
#include "Log.hxx"
#include <string>
#include <algorithm>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#ifdef _WIN32
#include <ws2tcpip.h>
#include <winsock.h>
#else
#include <sys/socket.h>
#include <netdb.h>
#endif
class OneServerSocket final : private SocketMonitor {
ServerSocket &parent;
const unsigned serial;
#ifdef HAVE_UN
AllocatedPath path;
#endif
const AllocatedSocketAddress address;
public:
template<typename A>
OneServerSocket(EventLoop &_loop, ServerSocket &_parent,
unsigned _serial,
A &&_address)
:SocketMonitor(_loop),
parent(_parent), serial(_serial),
#ifdef HAVE_UN
path(nullptr),
#endif
address(std::forward<A>(_address))
{
}
OneServerSocket(const OneServerSocket &other) = delete;
OneServerSocket &operator=(const OneServerSocket &other) = delete;
~OneServerSocket() {
if (IsDefined())
Close();
}
unsigned GetSerial() const {
return serial;
}
#ifdef HAVE_UN
void SetPath(AllocatedPath &&_path) {
assert(path.IsNull());
path = std::move(_path);
}
#endif
void Open();
using SocketMonitor::IsDefined;
using SocketMonitor::Close;
gcc_pure
std::string ToString() const noexcept {
return ::ToString(address);
}
void SetFD(SocketDescriptor _fd) noexcept {
SocketMonitor::Open(_fd);
SocketMonitor::ScheduleRead();
}
void Accept() noexcept;
private:
bool OnSocketReady(unsigned flags) noexcept override;
};
static constexpr Domain server_socket_domain("server_socket");
static int
get_remote_uid(int fd)
{
#ifdef HAVE_STRUCT_UCRED
struct ucred cred;
socklen_t len = sizeof (cred);
if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cred, &len) < 0)
return -1;
return cred.uid;
#else
#ifdef HAVE_GETPEEREID
uid_t euid;
gid_t egid;
if (getpeereid(fd, &euid, &egid) == 0)
return euid;
#else
(void)fd;
#endif
return -1;
#endif
}
inline void
OneServerSocket::Accept() noexcept
{
StaticSocketAddress peer_address;
UniqueSocketDescriptor peer_fd(GetSocket().AcceptNonBlock(peer_address));
if (!peer_fd.IsDefined()) {
const SocketErrorMessage msg;
FormatError(server_socket_domain,
"accept() failed: %s", (const char *)msg);
return;
}
if (!peer_fd.SetKeepAlive()) {
const SocketErrorMessage msg;
FormatError(server_socket_domain,
"Could not set TCP keepalive option: %s",
(const char *)msg);
}
parent.OnAccept(std::move(peer_fd), peer_address,
get_remote_uid(peer_fd.Get()));
}
bool
OneServerSocket::OnSocketReady(gcc_unused unsigned flags) noexcept
{
Accept();
return true;
}
inline void
OneServerSocket::Open()
{
assert(!IsDefined());
auto _fd = socket_bind_listen(address.GetFamily(),
SOCK_STREAM, 0,
address, 5);
/* register in the EventLoop */
SetFD(_fd.Release());
}
ServerSocket::ServerSocket(EventLoop &_loop)
:loop(_loop), next_serial(1) {}
/* this is just here to allow the OneServerSocket forward
declaration */
ServerSocket::~ServerSocket() {}
void
ServerSocket::Open()
{
OneServerSocket *good = nullptr, *bad = nullptr;
std::exception_ptr last_error;
for (auto &i : sockets) {
assert(i.GetSerial() > 0);
assert(good == nullptr || i.GetSerial() >= good->GetSerial());
if (bad != nullptr && i.GetSerial() != bad->GetSerial()) {
Close();
std::rethrow_exception(last_error);
}
try {
i.Open();
} catch (...) {
if (good != nullptr && good->GetSerial() == i.GetSerial()) {
const auto address_string = i.ToString();
const auto good_string = good->ToString();
FormatError(std::current_exception(),
"bind to '%s' failed "
"(continuing anyway, because "
"binding to '%s' succeeded)",
address_string.c_str(),
good_string.c_str());
} else if (bad == nullptr) {
bad = &i;
const auto address_string = i.ToString();
try {
std::throw_with_nested(FormatRuntimeError("Failed to bind to '%s'",
address_string.c_str()));
} catch (...) {
last_error = std::current_exception();
}
}
continue;
}
/* mark this socket as "good", and clear previous
errors */
good = &i;
if (bad != nullptr) {
bad = nullptr;
last_error = nullptr;
}
}
if (bad != nullptr) {
Close();
std::rethrow_exception(last_error);
}
}
void
ServerSocket::Close()
{
for (auto &i : sockets)
if (i.IsDefined())
i.Close();
}
OneServerSocket &
ServerSocket::AddAddress(SocketAddress address)
{
sockets.emplace_back(loop, *this, next_serial,
address);
return sockets.back();
}
OneServerSocket &
ServerSocket::AddAddress(AllocatedSocketAddress &&address)
{
sockets.emplace_back(loop, *this, next_serial,
std::move(address));
return sockets.back();
}
void
ServerSocket::AddFD(int _fd)
{
assert(_fd >= 0);
SocketDescriptor fd(_fd);
StaticSocketAddress address = fd.GetLocalAddress();
if (!address.IsDefined())
throw MakeSocketError("Failed to get socket address");
OneServerSocket &s = AddAddress(address);
s.SetFD(fd);
}
#ifdef HAVE_TCP
inline void
ServerSocket::AddPortIPv4(unsigned port)
{
AddAddress(IPv4Address(port));
}
#ifdef HAVE_IPV6
inline void
ServerSocket::AddPortIPv6(unsigned port)
{
struct sockaddr_in6 sin;
memset(&sin, 0, sizeof(sin));
sin.sin6_port = htons(port);
sin.sin6_family = AF_INET6;
AddAddress({(const sockaddr *)&sin, sizeof(sin)});
}
/**
* Is IPv6 supported by the kernel?
*/
gcc_pure
static bool
SupportsIPv6() noexcept
{
int fd = socket(AF_INET6, SOCK_STREAM, 0);
if (fd < 0)
return false;
close(fd);
return true;
}
#endif /* HAVE_IPV6 */
#endif /* HAVE_TCP */
void
ServerSocket::AddPort(unsigned port)
{
#ifdef HAVE_TCP
if (port == 0 || port > 0xffff)
throw std::runtime_error("Invalid TCP port");
#ifdef HAVE_IPV6
if (SupportsIPv6())
AddPortIPv6(port);
#endif
AddPortIPv4(port);
++next_serial;
#else /* HAVE_TCP */
(void)port;
throw std::runtime_error("TCP support is disabled");
#endif /* HAVE_TCP */
}
void
ServerSocket::AddHost(const char *hostname, unsigned port)
{
#ifdef HAVE_TCP
struct addrinfo *ai = resolve_host_port(hostname, port,
AI_PASSIVE, SOCK_STREAM);
AtScopeExit(ai) { freeaddrinfo(ai); };
for (const struct addrinfo *i = ai; i != nullptr; i = i->ai_next)
AddAddress(SocketAddress(i->ai_addr, i->ai_addrlen));
++next_serial;
#else /* HAVE_TCP */
(void)hostname;
(void)port;
throw std::runtime_error("TCP support is disabled");
#endif /* HAVE_TCP */
}
void
ServerSocket::AddPath(AllocatedPath &&path)
{
#ifdef HAVE_UN
unlink(path.c_str());
AllocatedSocketAddress address;
address.SetLocal(path.c_str());
OneServerSocket &s = AddAddress(std::move(address));
s.SetPath(std::move(path));
#else /* !HAVE_UN */
(void)path;
throw std::runtime_error("UNIX domain socket support is disabled");
#endif /* !HAVE_UN */
}