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Diffstat (limited to 'src/event/WakeFD.cxx')
| -rw-r--r-- | src/event/WakeFD.cxx | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/src/event/WakeFD.cxx b/src/event/WakeFD.cxx new file mode 100644 index 000000000..1a84f5645 --- /dev/null +++ b/src/event/WakeFD.cxx @@ -0,0 +1,225 @@ +/* + * Copyright (C) 2003-2013 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 "WakeFD.hxx" +#include "fd_util.h" +#include "gcc.h" + +#include <unistd.h> + +#ifdef WIN32 +#include <ws2tcpip.h> +#include <winsock2.h> +#include <cstring> /* for memset() */ +#endif + +#ifdef HAVE_EVENTFD +#include <sys/eventfd.h> +#endif + +#ifdef WIN32 +static bool PoorSocketPair(int fd[2]); +#endif + +bool +WakeFD::Create() +{ + assert(fds[0] == -1); + assert(fds[1] == -1); + +#ifdef WIN32 + return PoorSocketPair(fds); +#else +#ifdef HAVE_EVENTFD + fds[0] = eventfd_cloexec_nonblock(0, 0); + if (fds[0] >= 0) { + fds[1] = -2; + return true; + } +#endif + return pipe_cloexec_nonblock(fds) >= 0; +#endif +} + +void +WakeFD::Destroy() +{ +#ifdef WIN32 + closesocket(fds[0]); + closesocket(fds[1]); +#else + close(fds[0]); +#ifdef HAVE_EVENTFD + if (!IsEventFD()) +#endif + close(fds[1]); +#endif + +#ifndef NDEBUG + fds[0] = -1; + fds[1] = -1; +#endif +} + +bool +WakeFD::Read() +{ + assert(fds[0] >= 0); + +#ifdef WIN32 + assert(fds[1] >= 0); + char buffer[256]; + return recv(fds[0], buffer, sizeof(buffer), 0) > 0; +#else + +#ifdef HAVE_EVENTFD + if (IsEventFD()) { + eventfd_t value; + return read(fds[0], &value, + sizeof(value)) == (ssize_t)sizeof(value); + } +#endif + + assert(fds[1] >= 0); + + char buffer[256]; + return read(fds[0], buffer, sizeof(buffer)) > 0; +#endif +} + +void +WakeFD::Write() +{ + assert(fds[0] >= 0); + +#ifdef WIN32 + assert(fds[1] >= 0); + + send(fds[1], "", 1, 0); +#else + +#ifdef HAVE_EVENTFD + if (IsEventFD()) { + static constexpr eventfd_t value = 1; + gcc_unused ssize_t nbytes = + write(fds[0], &value, sizeof(value)); + return; + } +#endif + + assert(fds[1] >= 0); + + gcc_unused ssize_t nbytes = write(fds[1], "", 1); +#endif +} + +#ifdef WIN32 + +static void SafeCloseSocket(SOCKET s) +{ + int error = WSAGetLastError(); + closesocket(s); + WSASetLastError(error); +} + +/* Our poor man's socketpair() implementation + * Due to limited protocol/address family support and primitive error handling + * it's better to keep this as a private implementation detail of WakeFD + * rather than wide-available API. + */ +static bool PoorSocketPair(int fd[2]) +{ + assert (fd != nullptr); + + SOCKET listen_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); + if (listen_socket == INVALID_SOCKET) + return false; + + sockaddr_in address; + std::memset(&address, 0, sizeof(address)); + address.sin_family = AF_INET; + address.sin_addr.s_addr = htonl(INADDR_LOOPBACK); + + int ret = bind(listen_socket, + reinterpret_cast<sockaddr*>(&address), + sizeof(address)); + + if (ret < 0) { + SafeCloseSocket(listen_socket); + return false; + } + + ret = listen(listen_socket, 1); + + if (ret < 0) { + SafeCloseSocket(listen_socket); + return false; + } + + int address_len = sizeof(address); + ret = getsockname(listen_socket, + reinterpret_cast<sockaddr*>(&address), + &address_len); + + if (ret < 0) { + SafeCloseSocket(listen_socket); + return false; + } + + SOCKET socket0 = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); + if (socket0 == INVALID_SOCKET) { + SafeCloseSocket(listen_socket); + return false; + } + + ret = connect(socket0, + reinterpret_cast<sockaddr*>(&address), + sizeof(address)); + + if (ret < 0) { + SafeCloseSocket(listen_socket); + SafeCloseSocket(socket0); + return false; + } + + SOCKET socket1 = accept(listen_socket, nullptr, nullptr); + if (socket1 == INVALID_SOCKET) { + SafeCloseSocket(listen_socket); + SafeCloseSocket(socket0); + return false; + } + + SafeCloseSocket(listen_socket); + + u_long non_block = 1; + if (ioctlsocket(socket0, FIONBIO, &non_block) < 0 + || ioctlsocket(socket1, FIONBIO, &non_block) < 0) { + SafeCloseSocket(socket0); + SafeCloseSocket(socket1); + return false; + } + + fd[0] = static_cast<int>(socket0); + fd[1] = static_cast<int>(socket1); + + return true; +} + +#endif |