event/EventFD: move to libsystem

src/system/EventFD.cxx

@@ -0,0 +1,65 @@
+/*
+ * 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"
+#ifdef USE_EVENTFD
+#include "EventFD.hxx"
+#include "system/fd_util.h"
+#include "system/FatalError.hxx"
+#include "gcc.h"
+
+#include <assert.h>
+#include <unistd.h>
+
+#include <sys/eventfd.h>
+
+EventFD::EventFD()
+	:fd(eventfd_cloexec_nonblock(0, 0))
+{
+	if (fd < 0)
+		FatalSystemError("eventfd() failed");
+}
+
+EventFD::~EventFD()
+{
+	assert(fd >= 0);
+
+	close(fd);
+}
+
+bool
+EventFD::Read()
+{
+	assert(fd >= 0);
+
+	eventfd_t value;
+	return read(fd, &value, sizeof(value)) == (ssize_t)sizeof(value);
+}
+
+void
+EventFD::Write()
+{
+	assert(fd >= 0);
+
+	static constexpr eventfd_t value = 1;
+	gcc_unused ssize_t nbytes =
+		write(fd, &value, sizeof(value));
+}
+
+#endif /* USE_EVENTFD */

src/system/EventFD.hxx

@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_EVENT_FD_HXX
+#define MPD_EVENT_FD_HXX
+
+#include "check.h"
+
+/**
+ * A class that wraps eventfd().
+ *
+ * Errors in the constructor are fatal.
+ */
+class EventFD {
+	int fd;
+
+public:
+	EventFD();
+	~EventFD();
+
+	EventFD(const EventFD &other) = delete;
+	EventFD &operator=(const EventFD &other) = delete;
+
+	int Get() const {
+		return fd;
+	}
+
+	/**
+	 * Checks if Write() was called at least once since the last
+	 * Read() call.
+	 */
+	bool Read();
+
+	/**
+	 * Wakes up the reader.  Multiple calls to this function will
+	 * be combined to one wakeup.
+	 */
+	void Write();
+};
+
+#endif

src/system/EventPipe.cxx

@@ -0,0 +1,180 @@
+/*
+ * 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 "EventPipe.hxx"
+#include "system/fd_util.h"
+#include "system/FatalError.hxx"
+#include "gcc.h"
+
+#include <assert.h>
+#include <unistd.h>
+
+#ifdef WIN32
+#include <ws2tcpip.h>
+#include <winsock2.h>
+#include <cstring> /* for memset() */
+#endif
+
+#ifdef WIN32
+static bool PoorSocketPair(int fd[2]);
+#endif
+
+EventPipe::EventPipe()
+{
+#ifdef WIN32
+	bool success = PoorSocketPair(fds);
+#else
+	bool success = pipe_cloexec_nonblock(fds) >= 0;
+#endif
+	if (!success)
+		FatalSystemError("pipe() has failed");
+}
+
+EventPipe::~EventPipe()
+{
+#ifdef WIN32
+	closesocket(fds[0]);
+	closesocket(fds[1]);
+#else
+	close(fds[0]);
+	close(fds[1]);
+#endif
+}
+
+bool
+EventPipe::Read()
+{
+	assert(fds[0] >= 0);
+	assert(fds[1] >= 0);
+
+	char buffer[256];
+#ifdef WIN32
+	return recv(fds[0], buffer, sizeof(buffer), 0) > 0;
+#else
+	return read(fds[0], buffer, sizeof(buffer)) > 0;
+#endif
+}
+
+void
+EventPipe::Write()
+{
+	assert(fds[0] >= 0);
+	assert(fds[1] >= 0);
+
+#ifdef WIN32
+	send(fds[1], "", 1, 0);
+#else
+	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 EventPipe
+ * 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

src/system/EventPipe.hxx

@@ -0,0 +1,57 @@
+/*
+ * 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.
+ */
+
+#ifndef MPD_EVENT_PIPE_HXX
+#define MPD_EVENT_PIPE_HXX
+
+#include "check.h"
+
+/**
+ * A pipe that can be used to trigger an event to the read side.
+ *
+ * Errors in the constructor are fatal.
+ */
+class EventPipe {
+	int fds[2];
+
+public:
+	EventPipe();
+	~EventPipe();
+
+	EventPipe(const EventPipe &other) = delete;
+	EventPipe &operator=(const EventPipe &other) = delete;
+
+	int Get() const {
+		return fds[0];
+	}
+
+	/**
+	 * Checks if Write() was called at least once since the last
+	 * Read() call.
+	 */
+	bool Read();
+
+	/**
+	 * Wakes up the reader.  Multiple calls to this function will
+	 * be combined to one wakeup.
+	 */
+	void Write();
+};
+
+#endif /* MAIN_NOTIFY_H */