Gamemode/daemon/main.c

/*

Copyright (c) 2017, Feral Interactive
All rights reserved.

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 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
 * Neither the name of Feral Interactive nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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 */

/**
 * Simple daemon to allow user space programs to control the CPU governors
 *
 * The main process is responsible for bootstrapping the D-BUS daemon, caching
 * the initial governor settings, and then responding to requests over D-BUS.
 *
 * Clients register their pid(s) with the service, which are routinely checked
 * to see if they've expired. Once we reach our first actively registered client
 * we put the system into "game mode", i.e. move the CPU governor into a performance
 * mode.
 *
 * Upon exit, or when all clients have stopped running, we put the system back
 * into the default governor policy, which is invariably powersave or similar
 * on laptops. This ensures that the system is obtaining the maximum performance
 * whilst gaming, and allowed to sanely return to idle once the workload is
 * complete.
 */

#define _GNU_SOURCE

#include "daemonize.h"
#include "dbus_messaging.h"
#include "gamemode.h"
#include "logging.h"

#include <signal.h>
#include <string.h>
#include <unistd.h>

static void sigint_handler(__attribute__((unused)) int signo)
{
	LOG_MSG("Quitting by request...\n");

	/* Clean up nicely */
	game_mode_context_destroy(game_mode_context_instance());

	exit(EXIT_SUCCESS);
}

/**
 * Main bootstrap entry into gamemoded
 */
int main(int argc, char *argv[])
{
	GameModeContext *context = NULL;

	/* Gather command line options */
	bool daemon = false;
	bool use_syslog = false;
	int opt = 0;
	while ((opt = getopt(argc, argv, "dl")) != -1) {
		switch (opt) {
		case 'd':
			daemon = true;
			break;
		case 'l':
			use_syslog = true;
			break;
		default:
			fprintf(stderr, "Usage: %s [-d] [-l]\n", argv[0]);
			exit(EXIT_FAILURE);
			break;
		}
	}

	/* If syslog is requested, set it up with our process name */
	if (use_syslog) {
		set_use_syslog(argv[0]);
	}

	/* Daemonize ourselves first if asked */
	if (daemon) {
		daemonize(argv[0]);
	}

	/* Set up the game mode context */
	context = game_mode_context_instance();
	game_mode_context_init(context);

	/* Handle quits cleanly */
	if (signal(SIGINT, sigint_handler) == SIG_ERR) {
		FATAL_ERRORNO("Could not catch SIGINT");
	}

	/* Run the main dbus message loop */
	game_mode_context_loop(context);

	game_mode_context_destroy(context);

	/* Log we're finished */
	LOG_MSG("Quitting naturally...\n");
}