18 files changed, 1262 insertions, 0 deletions
diff --git a/src/client/Client.cxx b/src/client/Client.cxx
new file mode 100644
index 000000000..ce99faa89
--- /dev/null
+++ b/src/client/Client.cxx
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "util/Domain.hxx"
+
+const Domain client_domain("client");
diff --git a/src/client/Client.hxx b/src/client/Client.hxx
new file mode 100644
index 000000000..ec7d2d741
--- /dev/null
+++ b/src/client/Client.hxx
@@ -0,0 +1,192 @@
+/*
+ * Copyright (C) 2003-2014 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_CLIENT_H
+#define MPD_CLIENT_H
+
+#include "check.h"
+#include "ClientMessage.hxx"
+#include "command/CommandListBuilder.hxx"
+#include "event/FullyBufferedSocket.hxx"
+#include "event/TimeoutMonitor.hxx"
+#include "Compiler.h"
+
+#include <set>
+#include <string>
+#include <list>
+
+#include <stddef.h>
+#include <stdarg.h>
+
+struct sockaddr;
+class EventLoop;
+struct Partition;
+
+class Client final : private FullyBufferedSocket, TimeoutMonitor {
+public:
+	Partition &partition;
+	struct playlist &playlist;
+	struct PlayerControl &player_control;
+
+	unsigned permission;
+
+	/** the uid of the client process, or -1 if unknown */
+	int uid;
+
+	CommandListBuilder cmd_list;
+
+	unsigned int num;	/* client number */
+
+	/** is this client waiting for an "idle" response? */
+	bool idle_waiting;
+
+	/** idle flags pending on this client, to be sent as soon as
+	    the client enters "idle" */
+	unsigned idle_flags;
+
+	/** idle flags that the client wants to receive */
+	unsigned idle_subscriptions;
+
+	/**
+	 * A list of channel names this client is subscribed to.
+	 */
+	std::set<std::string> subscriptions;
+
+	/**
+	 * The number of subscriptions in #subscriptions.  Used to
+	 * limit the number of subscriptions.
+	 */
+	unsigned num_subscriptions;
+
+	/**
+	 * A list of messages this client has received.
+	 */
+	std::list<ClientMessage> messages;
+
+	Client(EventLoop &loop, Partition &partition,
+	       int fd, int uid, int num);
+
+	~Client() {
+		if (FullyBufferedSocket::IsDefined())
+			FullyBufferedSocket::Close();
+	}
+
+	bool IsConnected() const {
+		return FullyBufferedSocket::IsDefined();
+	}
+
+	gcc_pure
+	bool IsExpired() const {
+		return !FullyBufferedSocket::IsDefined();
+	}
+
+	void Close();
+	void SetExpired();
+
+	using FullyBufferedSocket::Write;
+
+	/**
+	 * returns the uid of the client process, or a negative value
+	 * if the uid is unknown
+	 */
+	int GetUID() const {
+		return uid;
+	}
+
+	/**
+	 * Is this client running on the same machine, connected with
+	 * a local (UNIX domain) socket?
+	 */
+	bool IsLocal() const {
+		return uid > 0;
+	}
+
+	unsigned GetPermission() const {
+		return permission;
+	}
+
+	void SetPermission(unsigned _permission) {
+		permission = _permission;
+	}
+
+	/**
+	 * Send "idle" response to this client.
+	 */
+	void IdleNotify();
+	void IdleAdd(unsigned flags);
+	bool IdleWait(unsigned flags);
+
+	enum class SubscribeResult {
+		/** success */
+		OK,
+
+		/** invalid channel name */
+		INVALID,
+
+		/** already subscribed to this channel */
+		ALREADY,
+
+		/** too many subscriptions */
+		FULL,
+	};
+
+	gcc_pure
+	bool IsSubscribed(const char *channel_name) const {
+		return subscriptions.find(channel_name) != subscriptions.end();
+	}
+
+	SubscribeResult Subscribe(const char *channel);
+	bool Unsubscribe(const char *channel);
+	void UnsubscribeAll();
+	bool PushMessage(const ClientMessage &msg);
+
+private:
+	/* virtual methods from class BufferedSocket */
+	virtual InputResult OnSocketInput(void *data, size_t length) override;
+	virtual void OnSocketError(Error &&error) override;
+	virtual void OnSocketClosed() override;
+
+	/* virtual methods from class TimeoutMonitor */
+	virtual void OnTimeout() override;
+};
+
+void client_manager_init(void);
+
+void
+client_new(EventLoop &loop, Partition &partition,
+	   int fd, const sockaddr *sa, size_t sa_length, int uid);
+
+/**
+ * Write a C string to the client.
+ */
+void client_puts(Client &client, const char *s);
+
+/**
+ * Write a printf-like formatted string to the client.
+ */
+void client_vprintf(Client &client, const char *fmt, va_list args);
+
+/**
+ * Write a printf-like formatted string to the client.
+ */
+gcc_printf(2,3)
+void
+client_printf(Client &client, const char *fmt, ...);
+
+#endif
diff --git a/src/client/ClientEvent.cxx b/src/client/ClientEvent.cxx
new file mode 100644
index 000000000..fd9f24b0d
--- /dev/null
+++ b/src/client/ClientEvent.cxx
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "util/Error.hxx"
+#include "Log.hxx"
+
+void
+Client::OnSocketError(Error &&error)
+{
+	FormatError(error, "error on client %d", num);
+
+	SetExpired();
+}
+
+void
+Client::OnSocketClosed()
+{
+	SetExpired();
+}
diff --git a/src/client/ClientExpire.cxx b/src/client/ClientExpire.cxx
new file mode 100644
index 000000000..5891756b6
--- /dev/null
+++ b/src/client/ClientExpire.cxx
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "Log.hxx"
+
+void
+Client::SetExpired()
+{
+	if (IsExpired())
+		return;
+
+	FullyBufferedSocket::Close();
+	TimeoutMonitor::Schedule(0);
+}
+
+void
+Client::OnTimeout()
+{
+	if (!IsExpired()) {
+		assert(!idle_waiting);
+		FormatDebug(client_domain, "[%u] timeout", num);
+	}
+
+	Close();
+}
diff --git a/src/client/ClientFile.cxx b/src/client/ClientFile.cxx
new file mode 100644
index 000000000..bdd9b0426
--- /dev/null
+++ b/src/client/ClientFile.cxx
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientFile.hxx"
+#include "Client.hxx"
+#include "protocol/Ack.hxx"
+#include "fs/Path.hxx"
+#include "fs/FileSystem.hxx"
+#include "util/Error.hxx"
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+bool
+client_allow_file(const Client &client, Path path_fs, Error &error)
+{
+#ifdef WIN32
+	(void)client;
+	(void)path_fs;
+
+	error.Set(ack_domain, ACK_ERROR_PERMISSION, "Access denied");
+	return false;
+#else
+	const int uid = client.GetUID();
+	if (uid >= 0 && (uid_t)uid == geteuid())
+		/* always allow access if user runs his own MPD
+		   instance */
+		return true;
+
+	if (uid <= 0) {
+		/* unauthenticated client */
+		error.Set(ack_domain, ACK_ERROR_PERMISSION, "Access denied");
+		return false;
+	}
+
+	struct stat st;
+	if (!StatFile(path_fs, st)) {
+		error.SetErrno();
+		return false;
+	}
+
+	if (st.st_uid != (uid_t)uid && (st.st_mode & 0444) != 0444) {
+		/* client is not owner */
+		error.Set(ack_domain, ACK_ERROR_PERMISSION, "Access denied");
+		return false;
+	}
+
+	return true;
+#endif
+}
diff --git a/src/client/ClientFile.hxx b/src/client/ClientFile.hxx
new file mode 100644
index 000000000..5a02a8df7
--- /dev/null
+++ b/src/client/ClientFile.hxx
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2003-2014 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_CLIENT_FILE_HXX
+#define MPD_CLIENT_FILE_HXX
+
+class Client;
+class Path;
+class Error;
+
+/**
+ * Is this client allowed to use the specified local file?
+ *
+ * Note that this function is vulnerable to timing/symlink attacks.
+ * We cannot fix this as long as there are plugins that open a file by
+ * its name, and not by file descriptor / callbacks.
+ *
+ * @param path_fs the absolute path name in filesystem encoding
+ * @return true if access is allowed
+ */
+bool
+client_allow_file(const Client &client, Path path_fs, Error &error);
+
+#endif
diff --git a/src/client/ClientGlobal.cxx b/src/client/ClientGlobal.cxx
new file mode 100644
index 000000000..8d90721e9
--- /dev/null
+++ b/src/client/ClientGlobal.cxx
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "config/ConfigGlobal.hxx"
+
+#define CLIENT_TIMEOUT_DEFAULT			(60)
+#define CLIENT_MAX_COMMAND_LIST_DEFAULT		(2048*1024)
+#define CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT	(8192*1024)
+
+int client_timeout;
+size_t client_max_command_list_size;
+size_t client_max_output_buffer_size;
+
+void client_manager_init(void)
+{
+	client_timeout = config_get_positive(CONF_CONN_TIMEOUT,
+					     CLIENT_TIMEOUT_DEFAULT);
+	client_max_command_list_size =
+		config_get_positive(CONF_MAX_COMMAND_LIST_SIZE,
+				    CLIENT_MAX_COMMAND_LIST_DEFAULT / 1024)
+		* 1024;
+
+	client_max_output_buffer_size =
+		config_get_positive(CONF_MAX_OUTPUT_BUFFER_SIZE,
+				    CLIENT_MAX_OUTPUT_BUFFER_SIZE_DEFAULT / 1024)
+		* 1024;
+}
diff --git a/src/client/ClientIdle.cxx b/src/client/ClientIdle.cxx
new file mode 100644
index 000000000..0b4fa5751
--- /dev/null
+++ b/src/client/ClientIdle.cxx
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "Idle.hxx"
+
+#include <assert.h>
+
+void
+Client::IdleNotify()
+{
+	assert(idle_waiting);
+	assert(idle_flags != 0);
+
+	unsigned flags = idle_flags;
+	idle_flags = 0;
+	idle_waiting = false;
+
+	const char *const*idle_names = idle_get_names();
+	for (unsigned i = 0; idle_names[i]; ++i) {
+		if (flags & (1 << i) & idle_subscriptions)
+			client_printf(*this, "changed: %s\n",
+				      idle_names[i]);
+	}
+
+	client_puts(*this, "OK\n");
+
+	TimeoutMonitor::ScheduleSeconds(client_timeout);
+}
+
+void
+Client::IdleAdd(unsigned flags)
+{
+	if (IsExpired())
+		return;
+
+	idle_flags |= flags;
+	if (idle_waiting && (idle_flags & idle_subscriptions))
+		IdleNotify();
+}
+
+bool
+Client::IdleWait(unsigned flags)
+{
+	assert(!idle_waiting);
+
+	idle_waiting = true;
+	idle_subscriptions = flags;
+
+	if (idle_flags & idle_subscriptions) {
+		IdleNotify();
+		return true;
+	} else {
+		/* disable timeouts while in "idle" */
+		TimeoutMonitor::Cancel();
+		return false;
+	}
+}
diff --git a/src/client/ClientInternal.hxx b/src/client/ClientInternal.hxx
new file mode 100644
index 000000000..a819d64b8
--- /dev/null
+++ b/src/client/ClientInternal.hxx
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2003-2014 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_CLIENT_INTERNAL_HXX
+#define MPD_CLIENT_INTERNAL_HXX
+
+#include "check.h"
+#include "Client.hxx"
+#include "command/CommandResult.hxx"
+
+static constexpr unsigned CLIENT_MAX_SUBSCRIPTIONS = 16;
+static constexpr unsigned CLIENT_MAX_MESSAGES = 64;
+
+extern const class Domain client_domain;
+
+extern int client_timeout;
+extern size_t client_max_command_list_size;
+extern size_t client_max_output_buffer_size;
+
+CommandResult
+client_process_line(Client &client, char *line);
+
+#endif
diff --git a/src/client/ClientList.cxx b/src/client/ClientList.cxx
new file mode 100644
index 000000000..101802479
--- /dev/null
+++ b/src/client/ClientList.cxx
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientList.hxx"
+#include "ClientInternal.hxx"
+
+#include <algorithm>
+
+#include <assert.h>
+
+void
+ClientList::Remove(Client &client)
+{
+	assert(size > 0);
+	assert(!list.empty());
+
+	auto i = std::find(list.begin(), list.end(), &client);
+	assert(i != list.end());
+	list.erase(i);
+	--size;
+}
+
+void
+ClientList::CloseAll()
+{
+	while (!list.empty()) {
+		delete list.front();
+		list.pop_front();
+
+#ifndef NDEBUG
+		--size;
+#endif
+	}
+
+	assert(size == 0);
+}
+
+void
+ClientList::IdleAdd(unsigned flags)
+{
+	assert(flags != 0);
+
+	for (const auto &client : list)
+		client->IdleAdd(flags);
+}
diff --git a/src/client/ClientList.hxx b/src/client/ClientList.hxx
new file mode 100644
index 000000000..35022fbf1
--- /dev/null
+++ b/src/client/ClientList.hxx
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2003-2014 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_CLIENT_LIST_HXX
+#define MPD_CLIENT_LIST_HXX
+
+#include <list>
+
+class Client;
+
+class ClientList {
+	const unsigned max_size;
+
+	unsigned size;
+	std::list<Client *> list;
+
+public:
+	ClientList(unsigned _max_size)
+		:max_size(_max_size), size(0) {}
+	~ClientList() {
+		CloseAll();
+	}
+
+	std::list<Client *>::iterator begin() {
+		return list.begin();
+	}
+
+	std::list<Client *>::iterator end() {
+		return list.end();
+	}
+
+	bool IsFull() const {
+		return size >= max_size;
+	}
+
+	void Add(Client &client) {
+		list.push_front(&client);
+		++size;
+	}
+
+	void Remove(Client &client);
+
+	void CloseAll();
+
+	void IdleAdd(unsigned flags);
+};
+
+#endif
diff --git a/src/client/ClientMessage.cxx b/src/client/ClientMessage.cxx
new file mode 100644
index 000000000..be6d2f007
--- /dev/null
+++ b/src/client/ClientMessage.cxx
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientMessage.hxx"
+#include "util/CharUtil.hxx"
+#include "Compiler.h"
+
+gcc_const
+static bool
+valid_channel_char(const char ch)
+{
+	return IsAlphaNumericASCII(ch) ||
+		ch == '_' || ch == '-' || ch == '.' || ch == ':';
+}
+
+bool
+client_message_valid_channel_name(const char *name)
+{
+	do {
+		if (!valid_channel_char(*name))
+			return false;
+	} while (*++name != 0);
+
+	return true;
+}
diff --git a/src/client/ClientMessage.hxx b/src/client/ClientMessage.hxx
new file mode 100644
index 000000000..3d28e01dc
--- /dev/null
+++ b/src/client/ClientMessage.hxx
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2003-2014 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_CLIENT_MESSAGE_H
+#define MPD_CLIENT_MESSAGE_H
+
+#include "Compiler.h"
+
+#include <string>
+
+/**
+ * A client-to-client message.
+ */
+class ClientMessage {
+	std::string channel, message;
+
+public:
+	template<typename T, typename U>
+	ClientMessage(T &&_channel, U &&_message)
+		:channel(std::forward<T>(_channel)),
+		 message(std::forward<U>(_message)) {}
+
+	const char *GetChannel() const {
+		return channel.c_str();
+	}
+
+	const char *GetMessage() const {
+		return message.c_str();
+	}
+};
+
+gcc_pure
+bool
+client_message_valid_channel_name(const char *name);
+
+#endif
diff --git a/src/client/ClientNew.cxx b/src/client/ClientNew.cxx
new file mode 100644
index 000000000..a080e9ec6
--- /dev/null
+++ b/src/client/ClientNew.cxx
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "ClientList.hxx"
+#include "Partition.hxx"
+#include "Instance.hxx"
+#include "system/fd_util.h"
+#include "system/Resolver.hxx"
+#include "Permission.hxx"
+#include "util/Error.hxx"
+#include "Log.hxx"
+
+#include <assert.h>
+#ifdef WIN32
+#include <winsock2.h>
+#else
+#include <sys/socket.h>
+#endif
+
+#ifdef HAVE_LIBWRAP
+#include <tcpd.h>
+#endif
+
+static const char GREETING[] = "OK MPD " PROTOCOL_VERSION "\n";
+
+Client::Client(EventLoop &_loop, Partition &_partition,
+	       int _fd, int _uid, int _num)
+	:FullyBufferedSocket(_fd, _loop, 16384, client_max_output_buffer_size),
+	 TimeoutMonitor(_loop),
+	 partition(_partition),
+	 playlist(partition.playlist), player_control(partition.pc),
+	 permission(getDefaultPermissions()),
+	 uid(_uid),
+	 num(_num),
+	 idle_waiting(false), idle_flags(0),
+	 num_subscriptions(0)
+{
+	TimeoutMonitor::ScheduleSeconds(client_timeout);
+}
+
+void
+client_new(EventLoop &loop, Partition &partition,
+	   int fd, const struct sockaddr *sa, size_t sa_length, int uid)
+{
+	static unsigned int next_client_num;
+	const auto remote = sockaddr_to_string(sa, sa_length);
+
+	assert(fd >= 0);
+
+#ifdef HAVE_LIBWRAP
+	if (sa->sa_family != AF_UNIX) {
+		// TODO: shall we obtain the program name from argv[0]?
+		const char *progname = "mpd";
+
+		struct request_info req;
+		request_init(&req, RQ_FILE, fd, RQ_DAEMON, progname, 0);
+
+		fromhost(&req);
+
+		if (!hosts_access(&req)) {
+			/* tcp wrappers says no */
+			FormatWarning(client_domain,
+				      "libwrap refused connection (libwrap=%s) from %s",
+				      progname, remote.c_str());
+
+			close_socket(fd);
+			return;
+		}
+	}
+#endif	/* HAVE_WRAP */
+
+	ClientList &client_list = *partition.instance.client_list;
+	if (client_list.IsFull()) {
+		LogWarning(client_domain, "Max connections reached");
+		close_socket(fd);
+		return;
+	}
+
+	Client *client = new Client(loop, partition, fd, uid,
+				    next_client_num++);
+
+	(void)send(fd, GREETING, sizeof(GREETING) - 1, 0);
+
+	client_list.Add(*client);
+
+	FormatInfo(client_domain, "[%u] opened from %s",
+		   client->num, remote.c_str());
+}
+
+void
+Client::Close()
+{
+	partition.instance.client_list->Remove(*this);
+
+	SetExpired();
+
+	FormatInfo(client_domain, "[%u] closed", num);
+	delete this;
+}
diff --git a/src/client/ClientProcess.cxx b/src/client/ClientProcess.cxx
new file mode 100644
index 000000000..96099a91c
--- /dev/null
+++ b/src/client/ClientProcess.cxx
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "protocol/Result.hxx"
+#include "command/AllCommands.hxx"
+#include "Log.hxx"
+
+#include <string.h>
+
+#define CLIENT_LIST_MODE_BEGIN "command_list_begin"
+#define CLIENT_LIST_OK_MODE_BEGIN "command_list_ok_begin"
+#define CLIENT_LIST_MODE_END "command_list_end"
+
+static CommandResult
+client_process_command_list(Client &client, bool list_ok,
+			    std::list<std::string> &&list)
+{
+	CommandResult ret = CommandResult::OK;
+	unsigned num = 0;
+
+	for (auto &&i : list) {
+		char *cmd = &*i.begin();
+
+		FormatDebug(client_domain, "process command \"%s\"", cmd);
+		ret = command_process(client, num++, cmd);
+		FormatDebug(client_domain, "command returned %i", ret);
+		if (ret != CommandResult::OK || client.IsExpired())
+			break;
+		else if (list_ok)
+			client_puts(client, "list_OK\n");
+	}
+
+	return ret;
+}
+
+CommandResult
+client_process_line(Client &client, char *line)
+{
+	CommandResult ret;
+
+	if (strcmp(line, "noidle") == 0) {
+		if (client.idle_waiting) {
+			/* send empty idle response and leave idle mode */
+			client.idle_waiting = false;
+			command_success(client);
+		}
+
+		/* do nothing if the client wasn't idling: the client
+		   has already received the full idle response from
+		   client_idle_notify(), which he can now evaluate */
+
+		return CommandResult::OK;
+	} else if (client.idle_waiting) {
+		/* during idle mode, clients must not send anything
+		   except "noidle" */
+		FormatWarning(client_domain,
+			      "[%u] command \"%s\" during idle",
+			      client.num, line);
+		return CommandResult::CLOSE;
+	}
+
+	if (client.cmd_list.IsActive()) {
+		if (strcmp(line, CLIENT_LIST_MODE_END) == 0) {
+			FormatDebug(client_domain,
+				    "[%u] process command list",
+				    client.num);
+
+			auto &&cmd_list = client.cmd_list.Commit();
+
+			ret = client_process_command_list(client,
+							  client.cmd_list.IsOKMode(),
+							  std::move(cmd_list));
+			FormatDebug(client_domain,
+				    "[%u] process command "
+				    "list returned %i", client.num, ret);
+
+			if (ret == CommandResult::CLOSE ||
+			    client.IsExpired())
+				return CommandResult::CLOSE;
+
+			if (ret == CommandResult::OK)
+				command_success(client);
+
+			client.cmd_list.Reset();
+		} else {
+			if (!client.cmd_list.Add(line)) {
+				FormatWarning(client_domain,
+					      "[%u] command list size "
+					      "is larger than the max (%lu)",
+					      client.num,
+					      (unsigned long)client_max_command_list_size);
+				return CommandResult::CLOSE;
+			}
+
+			ret = CommandResult::OK;
+		}
+	} else {
+		if (strcmp(line, CLIENT_LIST_MODE_BEGIN) == 0) {
+			client.cmd_list.Begin(false);
+			ret = CommandResult::OK;
+		} else if (strcmp(line, CLIENT_LIST_OK_MODE_BEGIN) == 0) {
+			client.cmd_list.Begin(true);
+			ret = CommandResult::OK;
+		} else {
+			FormatDebug(client_domain,
+				    "[%u] process command \"%s\"",
+				    client.num, line);
+			ret = command_process(client, 0, line);
+			FormatDebug(client_domain,
+				    "[%u] command returned %i",
+				    client.num, ret);
+
+			if (ret == CommandResult::CLOSE ||
+			    client.IsExpired())
+				return CommandResult::CLOSE;
+
+			if (ret == CommandResult::OK)
+				command_success(client);
+		}
+	}
+
+	return ret;
+}
diff --git a/src/client/ClientRead.cxx b/src/client/ClientRead.cxx
new file mode 100644
index 000000000..19deebd52
--- /dev/null
+++ b/src/client/ClientRead.cxx
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "Main.hxx"
+#include "event/Loop.hxx"
+#include "util/CharUtil.hxx"
+
+#include <string.h>
+
+BufferedSocket::InputResult
+Client::OnSocketInput(void *data, size_t length)
+{
+	char *p = (char *)data;
+	char *newline = (char *)memchr(p, '\n', length);
+	if (newline == nullptr)
+		return InputResult::MORE;
+
+	TimeoutMonitor::ScheduleSeconds(client_timeout);
+
+	BufferedSocket::ConsumeInput(newline + 1 - p);
+
+	/* skip whitespace at the end of the line */
+	while (newline > p && IsWhitespaceOrNull(newline[-1]))
+		--newline;
+
+	/* terminate the string at the end of the line */
+	*newline = 0;
+
+	CommandResult result = client_process_line(*this, p);
+	switch (result) {
+	case CommandResult::OK:
+	case CommandResult::IDLE:
+	case CommandResult::ERROR:
+		break;
+
+	case CommandResult::KILL:
+		Close();
+		main_loop->Break();
+		return InputResult::CLOSED;
+
+	case CommandResult::FINISH:
+		if (Flush())
+			Close();
+		return InputResult::CLOSED;
+
+	case CommandResult::CLOSE:
+		Close();
+		return InputResult::CLOSED;
+	}
+
+	if (IsExpired()) {
+		Close();
+		return InputResult::CLOSED;
+	}
+
+	return InputResult::AGAIN;
+}
diff --git a/src/client/ClientSubscribe.cxx b/src/client/ClientSubscribe.cxx
new file mode 100644
index 000000000..8ea2e363b
--- /dev/null
+++ b/src/client/ClientSubscribe.cxx
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "Idle.hxx"
+
+#include <assert.h>
+
+Client::SubscribeResult
+Client::Subscribe(const char *channel)
+{
+	assert(channel != nullptr);
+
+	if (!client_message_valid_channel_name(channel))
+		return Client::SubscribeResult::INVALID;
+
+	if (num_subscriptions >= CLIENT_MAX_SUBSCRIPTIONS)
+		return Client::SubscribeResult::FULL;
+
+	auto r = subscriptions.insert(channel);
+	if (!r.second)
+		return Client::SubscribeResult::ALREADY;
+
+	++num_subscriptions;
+
+	idle_add(IDLE_SUBSCRIPTION);
+
+	return Client::SubscribeResult::OK;
+}
+
+bool
+Client::Unsubscribe(const char *channel)
+{
+	const auto i = subscriptions.find(channel);
+	if (i == subscriptions.end())
+		return false;
+
+	assert(num_subscriptions > 0);
+
+	subscriptions.erase(i);
+	--num_subscriptions;
+
+	idle_add(IDLE_SUBSCRIPTION);
+
+	assert((num_subscriptions == 0) ==
+	       subscriptions.empty());
+
+	return true;
+}
+
+void
+Client::UnsubscribeAll()
+{
+	subscriptions.clear();
+	num_subscriptions = 0;
+}
+
+bool
+Client::PushMessage(const ClientMessage &msg)
+{
+	if (messages.size() >= CLIENT_MAX_MESSAGES ||
+	    !IsSubscribed(msg.GetChannel()))
+		return false;
+
+	if (messages.empty())
+		IdleAdd(IDLE_MESSAGE);
+
+	messages.push_back(msg);
+	return true;
+}
diff --git a/src/client/ClientWrite.cxx b/src/client/ClientWrite.cxx
new file mode 100644
index 000000000..b5d172a8d
--- /dev/null
+++ b/src/client/ClientWrite.cxx
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2003-2014 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 "ClientInternal.hxx"
+#include "util/FormatString.hxx"
+
+#include <string.h>
+
+/**
+ * Write a block of data to the client.
+ */
+static void
+client_write(Client &client, const char *data, size_t length)
+{
+	/* if the client is going to be closed, do nothing */
+	if (client.IsExpired() || length == 0)
+		return;
+
+	client.Write(data, length);
+}
+
+void
+client_puts(Client &client, const char *s)
+{
+	client_write(client, s, strlen(s));
+}
+
+void
+client_vprintf(Client &client, const char *fmt, va_list args)
+{
+	char *p = FormatNewV(fmt, args);
+	client_write(client, p, strlen(p));
+	delete[] p;
+}
+
+void
+client_printf(Client &client, const char *fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	client_vprintf(client, fmt, args);
+	va_end(args);
+}