main: Add Windows Service support

I've added PIPE_EVENT_SHUTDOWN because calling g_main_loop_quit() do not work when called from another thread.
Main thread was sleeping in g_poll() so I needed some way to wake it up.

By some strange reason call close(event_pipe[0]) in event_pipe_deinit() hangs.
In current implementation that code never reached so that was not a problem :-)
I've added a conditional to leave event_pipe[0] open on Win32.

Makefile.am

@@ -278,6 +278,7 @@ src_mpd_SOURCES = \
 	src/log.c \
 	src/ls.c \
 	src/main.c \
+	src/main_win32.c \
 	src/event_pipe.c \
 	src/daemon.c \
 	src/AudioCompress/compress.c \

src/event_pipe.c

@@ -116,7 +116,10 @@ void event_pipe_deinit(void)
 	g_source_remove(event_pipe_source_id);
 	g_io_channel_unref(event_channel);
 
+#ifndef WIN32
+	/* By some strange reason this call hangs on Win32 */
 	close(event_pipe[0]);
+#endif
 	close(event_pipe[1]);
 }
 

src/event_pipe.h

@@ -44,6 +44,9 @@ enum pipe_event {
 	/** a hardware mixer plugin has detected a change */
 	PIPE_EVENT_MIXER,
 
+	/** shutdown requested */
+	PIPE_EVENT_SHUTDOWN,
+
 	PIPE_EVENT_MAX
 };
 

src/main.c

@@ -269,7 +269,25 @@ idle_event_emitted(void)
 		client_manager_idle_add(flags);
 }
 
+/**
+ * event_pipe callback function for PIPE_EVENT_SHUTDOWN
+ */
+static void
+shutdown_event_emitted(void)
+{
+	g_main_loop_quit(main_loop);
+}
+
 int main(int argc, char *argv[])
+{
+#ifdef WIN32
+	return win32_main(argc, argv);
+#else
+	return mpd_main(argc, argv);
+#endif
+}
+
+int mpd_main(int argc, char *argv[])
 {
 	struct options options;
 	clock_t start;
@@ -324,6 +342,7 @@ int main(int argc, char *argv[])
 
 	event_pipe_init();
 	event_pipe_register(PIPE_EVENT_IDLE, idle_event_emitted);
+	event_pipe_register(PIPE_EVENT_SHUTDOWN, shutdown_event_emitted);
 
 	path_global_init();
 	glue_mapper_init();
@@ -392,10 +411,17 @@ int main(int argc, char *argv[])
 	   playlist_state_restore() */
 	pc_update_audio();
 
-	/* run the main loop */
+#ifdef WIN32
+	win32_app_started();
+#endif
 
+	/* run the main loop */
 	g_main_loop_run(main_loop);
 
+#ifdef WIN32
+	win32_app_stopping();
+#endif
+
 	/* cleanup */
 
 	g_main_loop_unref(main_loop);

src/main.h

@@ -28,4 +28,45 @@ extern GMainLoop *main_loop;
 
 extern GCond *main_cond;
 
+/**
+ * A entry point for application.
+ * On non-Windows platforms this is called directly from main()
+ * On Windows platform this is called from win32_main()
+ * after doing some initialization.
+ */
+int mpd_main(int argc, char *argv[]);
+
+#ifdef WIN32
+
+/**
+ * If program is run as windows service performs nessesary initialization
+ * and then calls mpd_main() with specified arguments.
+ * If program is run as a regular application calls mpd_main() immediately.
+ */
+int
+win32_main(int argc, char *argv[]);
+
+/**
+ * When running as a service reports to service control manager
+ * that our service is started.
+ * When running as a console application enables console handler that will
+ * trigger PIPE_EVENT_SHUTDOWN when user closes console window
+ * or presses Ctrl+C.
+ * This function should be called just before entering main loop.
+ */
+void
+win32_app_started(void);
+
+/**
+ * When running as a service reports to service control manager
+ * that our service is about to stop.
+ * When running as a console application enables console handler that will
+ * catch all shutdown requests and ignore them.
+ * This function should be called just after leaving main loop.
+ */
+void
+win32_app_stopping(void);
+
+#endif
+
 #endif

src/main_win32.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2003-2010 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 "main.h"
+
+#ifdef WIN32
+
+#include "event_pipe.h"
+
+#include <glib.h>
+
+#define WINVER 0x0501
+#include <windows.h>
+
+static int service_argc;
+static char **service_argv;
+static char service_name[] = "";
+static BOOL ignore_console_events;
+static SERVICE_STATUS_HANDLE service_handle;
+
+static void WINAPI
+service_main(DWORD argc, CHAR *argv[]);
+
+static SERVICE_TABLE_ENTRY service_registry[] = {
+	{service_name, service_main},
+	{NULL, NULL}
+};
+
+static void
+service_notify_status(DWORD status_code)
+{
+	SERVICE_STATUS current_status;
+
+	current_status.dwServiceType = SERVICE_WIN32_OWN_PROCESS;
+	current_status.dwControlsAccepted = status_code == SERVICE_START_PENDING
+		? 0
+		: SERVICE_ACCEPT_SHUTDOWN | SERVICE_ACCEPT_STOP;
+
+	current_status.dwCurrentState = status_code;
+	current_status.dwWin32ExitCode = NO_ERROR;
+	current_status.dwCheckPoint = 0;
+	current_status.dwWaitHint = 1000;
+
+	SetServiceStatus(service_handle, &current_status);
+}
+
+static DWORD WINAPI
+service_dispatcher(G_GNUC_UNUSED DWORD control, G_GNUC_UNUSED DWORD event_type,
+		   G_GNUC_UNUSED void *event_data, G_GNUC_UNUSED void *context)
+{
+	switch (control) {
+	case SERVICE_CONTROL_SHUTDOWN:
+	case SERVICE_CONTROL_STOP:
+		event_pipe_emit(PIPE_EVENT_SHUTDOWN);
+		return NO_ERROR;
+	default:
+		return NO_ERROR;
+	}
+}
+
+static void WINAPI
+service_main(G_GNUC_UNUSED DWORD argc, G_GNUC_UNUSED CHAR *argv[])
+{
+	DWORD error_code;
+	gchar* error_message;
+
+	service_handle =
+		RegisterServiceCtrlHandlerEx(service_name,
+					     service_dispatcher, NULL);
+
+	if (service_handle == 0) {
+		error_code = GetLastError();
+		error_message = g_win32_error_message(error_code);
+		g_error("RegisterServiceCtrlHandlerEx() failed: %s",
+			error_message);
+	}
+
+	service_notify_status(SERVICE_START_PENDING);
+	mpd_main(service_argc, service_argv);
+	service_notify_status(SERVICE_STOPPED);
+}
+
+static BOOL WINAPI
+console_handler(DWORD event)
+{
+	switch (event) {
+	case CTRL_C_EVENT:
+	case CTRL_CLOSE_EVENT:
+		if (!ignore_console_events)
+			event_pipe_emit(PIPE_EVENT_SHUTDOWN);
+		return TRUE;
+	default:
+		return FALSE;
+	}
+}
+
+int win32_main(int argc, char *argv[])
+{
+	DWORD error_code;
+	gchar* error_message;
+
+	service_argc = argc;
+	service_argv = argv;
+
+	if (StartServiceCtrlDispatcher(service_registry))
+		return 0; /* run as service successefully */
+
+	error_code = GetLastError();
+	if (error_code == ERROR_FAILED_SERVICE_CONTROLLER_CONNECT) {
+		/* running as console app */
+		SetConsoleTitle("Music Player Daemon");
+		ignore_console_events = TRUE;
+		SetConsoleCtrlHandler(console_handler, TRUE);
+		return mpd_main(argc, argv);
+	}
+
+	error_message = g_win32_error_message(error_code);
+	g_error("StartServiceCtrlDispatcher() failed: %s", error_message);
+}
+
+void win32_app_started()
+{
+	if (service_handle != 0)
+		service_notify_status(SERVICE_RUNNING);
+	else
+		ignore_console_events = FALSE;
+}
+
+void win32_app_stopping()
+{
+	if (service_handle != 0)
+		service_notify_status(SERVICE_STOP_PENDING);
+	else
+		ignore_console_events = TRUE;
+}
+
+#endif