Initial 0.1 commit

This is a small daemon/libary to enable games to request a
performance "game mode" from the system.

Currently only implemented to upgrade the CPU governor and
automatically downgrade it once done.

A game only needs to load libgamemodeauto to activate the request.
Which means an LD_PRELOAD can be applied to any game to activate
the mode as needed.

However gamemode_client.h can be used to manually activate/deactivate
the mode as needed, and also perform error checking.

The libs are miminal loaders to call into an installed libgamemode
which, if the daemon is installed and running, will send through
the equivelant game mode request, and magic will happen.

See the README.md for more details.

Currently licensed under the BSD 3 clause license.

.gitignore

@@ -0,0 +1,2 @@
+build/
+*.swp

LICENSE.txt

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+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.

README.md

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+# GameMode
+
+A preliminary implementation of a daemon/lib combo to allow games to request a performance mode from the host OS on Linux. It was designed primarily as a stop-gap solution to problems with the Intel and AMD CPU powersave or ondemand governors, but is intended to be expanded beyond just CPU power states as needed.
+
+Currently using `sd-bus` on the user bus internally for messaging
+
+---
+## Components
+
+### Host
+#### gamemoded
+Runs in the background, waits for requests, refcounts and also checks caller PID lifetime.
+
+Accepts `-d` (daemonize) and `-l` (log to syslog)
+
+#### libgamemode
+Dynamic library to dispatch requests to the daemon
+
+Note: Behaviour of `gamemoded` may change, so `libgamemode` should never be linked with directly.
+
+#### cpugovctl
+Small program used to to control the cpu governor.
+
+Accepts `get` (gets current governor) and `set <GOVERNOR>` (sets the current governor).
+
+### Clients
+#### libgamemodeauto
+Simple dynamic library that automatically requests game mode when loaded. Minimal dependencies.
+
+Useful to `LD_PRELOAD` into any game as needed.
+
+#### gamemode\_client.h
+Very small header only lib that lets a game request game mode and handle errors. Minimal dependencies.
+
+Can also be included with `GAMEMODE_AUTO` defined to behave automatically.
+
+---
+## Build and install
+
+### Daemon and host library
+
+#### Dependencies
+* meson
+* systemd
+
+```bash
+# Ubuntu
+apt install meson libsystemd-dev
+# Arch
+pacman -S meson systemd
+```
+
+```bash
+git clone <git repo>
+cd gamemode
+meson --prefix=/usr build
+cd build
+ninja
+sudo ninja install
+```
+
+---
+## Using with any game or program
+
+After installing `libgamemodeauto.so` simple preload it into the program. Examples:
+```bash
+LD_PRELOAD=/usr/lib/libgamemodeauto.so ./game
+```
+Or steam launch options
+```bash
+LD_PRELOAD=/usr/lib/libgamemodeauto.so %command%
+```
+
+---
+## Building into a game or program
+
+You may want to build in functionality directly into an app, this stops the need for users to have to manually set anything up.
+
+`gamemode_client.h` and `libgamemodeauto` are safe to use regardless of whether libgamemode and gamemoded are installed on the system. They also do not require `systemd`.
+
+### Using directly
+```C
+#include "gamemode_client.h"
+
+	if( gamemode_request_start() < 0 )
+		fprintf( stderr, "gamemode request failed: %s\n", gamemode_error_string() );
+
+	/* run game... */
+
+	gamemode_request_end(); // Not required, gamemoded will clean up after game exists anyway
+```
+
+### Using automatically
+
+#### Option 1: Include in code
+```C
+#define GAMEMODE_AUTO
+#include "gamemode_client.h"
+```
+
+#### Option 2: Link and distribute
+Add `-lgamemodeauto` to linker arguments and distribute `libgamemodeauto.so` with the game
+
+#### Option 3: Distribute and script
+Distribute `libgamemodeauto.so` with the game and add to LD\_PRELOAD in a launch script
+
+---
+## TODO
+
+* Use polkit for cpugovctl (currently simply using chmod +4555)
+* Implement some kind of user confuguration to allow for whitelists, extra behaviour, etc.

bootstrap.sh

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+#!/bin/bash
+# Simple bootstrap script to build and run the daemon
+set -e
+
+# Echo the rest so it's obvious
+set -x
+meson --prefix=/usr build
+cd build
+ninja
+
+# Verify user wants to install
+set +x
+read -p "Install to /usr? [Yy] " -r
+[[ $REPLY =~ ^[Yy]$ ]]
+set -x
+
+sudo ninja install
+
+# Verify user wants to run the daemon
+set +x
+read -p "Enable and run the daemon? [Yy] " -r
+[[ $REPLY =~ ^[Yy]$ ]]
+set -x
+
+systemctl --user daemon-reload
+systemctl --user enable gamemoded
+systemctl --user start gamemoded
+systemctl --user status gamemoded

daemon/cpugovctl.c

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+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "logging.h"
+
+#include <sys/types.h>
+#include <dirent.h>
+#include <ctype.h>
+
+static const int max_governors       = 128;
+static const int max_governor_length = PATH_MAX+1;
+
+// Governers are located at /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
+static int fetch_governors( char governors[max_governors][max_governor_length] )
+{
+	const char* cpu_base_path = "/sys/devices/system/cpu/";
+	DIR* dir = opendir( cpu_base_path );
+	if( !dir )
+		FATAL_ERRORNO( "cpu device path not found" );
+
+	int num_governors = 0;
+
+	// Explore the directory
+	struct dirent* ent;
+	while( ( ent = readdir(dir) ) && num_governors < max_governors )
+	{
+		// CPU directories all start with "cpu"
+		if( strncmp( ent->d_name, "cpu", 3 ) == 0 )
+		{
+			// Check if this matches "cpu\d+"
+			const int len = strlen( ent->d_name );
+			if( len > 3 && len < 5
+				&& isdigit( ent->d_name[3] ) )
+			{
+				// Construct the full path
+				char path[PATH_MAX] = {};
+				snprintf( path, sizeof(path), "%s%s/cpufreq/scaling_governor", cpu_base_path, ent->d_name );
+
+				// Get the real path to the file
+				// Traditionally cpufreq symlinks to a policy directory that can be shared
+				// So let's prevent duplicates
+				char fullpath[PATH_MAX] = {};
+				const char* ptr = realpath( path, fullpath );
+				if( fullpath != ptr )
+					continue;
+
+				// Only add if unique
+				for( int i = 0; i < num_governors; i++ )
+				{
+					if( strncmp( fullpath, governors[i], max_governor_length ) == 0 )
+						continue;
+				}
+
+				strncpy( governors[num_governors], fullpath, max_governor_length );
+				num_governors++;
+			}
+		}
+	}
+	closedir(dir);
+
+	return num_governors;
+}
+
+// Get the current governor state
+const char* get_gov_state()
+{
+	// To be returned
+	static char governor[64];
+	memset( governor, 0, sizeof(governor) );
+
+	// State of all the overnors
+	char governors[max_governors][max_governor_length];
+	memset( governors, 0, sizeof(governors) );
+	int num = fetch_governors( governors );
+
+	// Check the list
+	for( int i = 0; i < num; i++ )
+	{
+		const char* gov = governors[i];
+
+		FILE* f = fopen( gov, "r" );
+		if( !f )
+		{
+			LOG_ERROR( "Failed to open file for read %s\n", gov );
+			continue;
+		}
+
+		// Pull out the file contents
+		fseek( f, 0, SEEK_END );
+		int length = ftell(f);
+		fseek( f, 0, SEEK_SET );
+
+		char contents[length];
+
+		if( fread(contents, 1, length, f) > 0 )
+		{
+			// Files have a newline
+			strtok(contents, "\n");
+			if( strlen(governor) > 0 && strncmp( governor, contents, 64 ) != 0 )
+			{
+				// Don't handle the mixed case, this shouldn't ever happen
+				// But it is a clear sign we shouldn't carry on
+				LOG_ERROR( "Governors malformed: got \"%s\", expected \"%s\"", contents, governor );
+				return "malformed";
+			}
+				
+			strncpy( governor, contents, sizeof(governor) );
+		}
+		else
+		{
+			LOG_ERROR( "Failed to read contents of %s\n", gov );
+		}
+
+		fclose( f );
+	}
+
+	return governor;
+}
+
+// Sets all governors to a value
+void set_gov_state( const char* value )
+{
+	char governors[max_governors][max_governor_length];
+	memset( governors, 0, sizeof(governors) );
+	int num = fetch_governors( governors );
+
+	LOG_MSG( "Setting governors to %s\n", value );
+	for( int i = 0; i < num; i++ )
+	{
+		const char* gov = governors[i];
+		FILE* f = fopen( gov, "w" );
+		if( !f )
+		{
+			LOG_ERROR( "Failed to open file for write %s\n", gov );
+			continue;
+		}
+
+		fprintf( f, "%s\n", value );
+		fclose( f );
+	}
+}
+
+// Main entry point
+int main( int argc, char *argv[] )
+{
+	if( argc < 2 )
+	{
+		fprintf( stderr, "usage: cpugovctl [get] [set VALUE]\n" );
+		exit( EXIT_FAILURE );
+	}
+
+	if( strncmp( argv[1], "get", 3 ) == 0 )
+	{
+		printf( "%s", get_gov_state() );
+	}
+	else if( strncmp( argv[1], "set", 3 ) == 0 )
+	{
+		const char* value = argv[2];
+		set_gov_state( value );
+	}
+	else
+	{
+		exit( EXIT_FAILURE );
+	}
+}
+

daemon/daemonize.c

@@ -0,0 +1,69 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "daemonize.h"
+#include "logging.h"
+
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+// function to daemonize the process
+void daemonize( char* name )
+{
+	// Fork once
+	pid_t pid = fork();
+	if( pid < 0 )
+		FATAL_ERRORNO( "Failed to fork" );
+
+	if( pid != 0 )
+	{
+		LOG_MSG( "Daemon launched...\n" );
+		exit( EXIT_SUCCESS );
+	}
+
+	// Fork a second time
+	pid = fork();
+	if( pid < 0 )
+		FATAL_ERRORNO( "Failed to fork" );
+	else if( pid > 0 )
+		exit( EXIT_SUCCESS );
+
+	// Continue to set up as a daemon
+	umask(0);
+	if ( setsid() < 0 )
+		FATAL_ERRORNO( "Failed to create process group\n" );
+	if ( chdir( "/" ) < 0 )
+		FATAL_ERRORNO( "Failed to change to root directory\n" );
+	close( STDIN_FILENO );
+	close( STDOUT_FILENO );
+	close( STDERR_FILENO );
+}

daemon/daemonize.h

@@ -0,0 +1,38 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _DAEMONIZE_GAMEMODE_H_
+#define _DAEMONIZE_GAMEMODE_H_
+
+// Function to daemonize the process
+// Exits with error in case of failure
+void daemonize( char* name );
+
+#endif // _DAEMONIZE_GAMEMODE_H_

daemon/dbus_messaging.c

@@ -0,0 +1,154 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "dbus_messaging.h"
+#include "logging.h"
+#include "gamemode.h"
+#include "governors.h"
+#include "daemonize.h"
+
+#include <stdlib.h>
+
+#include <systemd/sd-bus.h>
+
+// sd-bus tracker values
+static sd_bus*      bus  = NULL;
+static sd_bus_slot* slot = NULL;
+
+// Clean up any resources as needed
+static void clean_up()
+{
+	if( slot )
+		sd_bus_slot_unref( slot );
+	slot = NULL;
+	if( bus )
+		sd_bus_unref( bus );
+	bus = NULL;
+}
+
+// Callback for RegisterGame
+static int method_register_game( sd_bus_message *m,
+		void *userdata,
+		sd_bus_error *ret_error )
+{
+	int pid = 0;
+
+	int ret = sd_bus_message_read( m, "i", &pid );
+	if( ret < 0 )
+	{
+		LOG_ERROR( "Failed to parse input parameters: %s\n", strerror(-ret) );
+		return ret;
+	}
+
+	register_game( pid );
+
+	return sd_bus_reply_method_return( m, "i", 0 );
+}
+
+// Callback for UnregisterGame
+static int method_unregister_game( sd_bus_message *m,
+		void *userdata,
+		sd_bus_error *ret_error )
+{
+	int pid = 0;
+
+	int ret = sd_bus_message_read( m, "i", &pid );
+	if( ret < 0 )
+	{
+		LOG_ERROR( "Failed to parse input parameters: %s\n", strerror(-ret) );
+		return ret;
+	}
+
+	unregister_game( pid );
+
+	return sd_bus_reply_method_return( m, "i", 0 );
+}
+
+// Vtable for function dispatch
+static const sd_bus_vtable gamemode_vtable[] = {
+	SD_BUS_VTABLE_START( 0 ),
+	SD_BUS_METHOD( "RegisterGame",   "i", "i", method_register_game,     SD_BUS_VTABLE_UNPRIVILEGED ),
+	SD_BUS_METHOD( "UnregisterGame", "i", "i", method_unregister_game,   SD_BUS_VTABLE_UNPRIVILEGED ),
+	SD_BUS_VTABLE_END
+};
+
+// Main loop, will not return until something request a quit
+void run_dbus_main_loop( bool system_dbus )
+{
+	// Set up function to handle clean up of resources
+	atexit( clean_up );
+	int ret = 0;
+	
+	// Connec to the desired bus
+	if( system_dbus )
+		ret = sd_bus_open_system( &bus );
+	else
+		ret = sd_bus_open_user( &bus );
+
+	if( ret < 0 )
+		FATAL_ERROR( "Failed to connect to the bus: %s", strerror(-ret) );
+
+	// Create the object to allow connections
+	ret = sd_bus_add_object_vtable( bus,
+			&slot,
+			"/com/feralinteractive/GameMode",
+			"com.feralinteractive.GameMode",
+			gamemode_vtable,
+			NULL );
+
+	if( ret < 0 )
+		FATAL_ERROR( "Failed to install GameMode object: %s", strerror(-ret) );
+
+	// Request our name
+	ret = sd_bus_request_name( bus, "com.feralinteractive.GameMode", 0 );
+	if( ret < 0 )
+		FATAL_ERROR( "Failed to acquire service name: %s", strerror(-ret) );
+
+	LOG_MSG( "Successfully initialised bus with name [%s]...\n", "com.feralinteractive.GameMode" );
+
+	// Now loop, waiting for callbacks
+	for(;;)
+	{
+		ret = sd_bus_process( bus, NULL );
+		if( ret < 0 )
+			FATAL_ERROR( "Failure when processing the bus: %s", strerror(-ret) );
+
+		// We're done processing
+		if( ret > 0 )
+			continue;
+
+		// Wait for more
+		ret = sd_bus_wait( bus, (uint64_t)-1 );
+		if( ret < 0 && -ret != EINTR )
+			FATAL_ERROR( "Failure when waiting on bus: %s", strerror(-ret) );
+	}
+}
+
+

daemon/dbus_messaging.h

@@ -0,0 +1,40 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _DBUS_MESSAGING_GAMEMODE_H_
+#define _DBUS_MESSAGING_GAMEMODE_H_
+
+#include <stdbool.h>
+
+// Run the main dbus loop
+// Will not return until finished
+void run_dbus_main_loop( bool system_dbus );
+
+#endif // _DBUS_MESSAGING_GAMEMODE_H_

daemon/gamemode.c

@@ -0,0 +1,177 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "gamemode.h"
+#include "logging.h"
+#include "governors.h"
+
+#include <signal.h>
+#include <string.h>
+
+// Storage for game PIDs
+#define MAX_GAMES 16
+static int game_pids[MAX_GAMES];
+static int num_games = 0;
+
+// Constant to control how often we'll wake up and check process ids
+static const int wakeup_timer = 5;
+static void start_alarm_timer();
+
+// Called once to enter game mode
+// Must be followed by a call to leave_game_mode
+// Must be called after init_game_mode
+static void enter_game_mode()
+{
+	LOG_MSG( "Entering Game Mode...\n" );
+	set_governors( "performance" );
+
+	// Set up the alarm callback
+	start_alarm_timer();
+}
+
+// Called once to leave game mode
+// Must be called after an equivelant call to enter_game_mode
+static void leave_game_mode()
+{
+	LOG_MSG( "Leaving Game Mode...\n" );
+	set_governors( NULL );
+}
+
+// Set up an alarm callback to check for current process ids
+static void alarm_handler( int sig )
+{
+	// Quick return if no games, and don't register another callback
+	if( num_games == 0 )
+		return;
+
+	// Check if games are alive at all
+	for( int i = 0; i < num_games; )
+	{
+		int game = game_pids[i];
+
+		if( kill( game, 0 ) != 0 )
+		{
+			LOG_MSG( "Removing expired game [%i]...\n", game );
+			memmove( &game_pids[i], &game_pids[i+1], MAX_GAMES - (i+1) );
+			num_games--;
+		}
+		else
+			i++;
+	}
+
+	// Either trigger another alarm, or reset the governors
+	if( num_games )
+		start_alarm_timer();
+	else
+		leave_game_mode();
+}
+
+// Call to trigger starting the alarm timer for pid checks
+static void start_alarm_timer()
+{
+	// Set up process check alarms
+	signal( SIGALRM, alarm_handler );
+	alarm( wakeup_timer );
+}
+
+// Intialise any game mode needs
+void init_game_mode()
+{
+	// Read current governer state before setting up any message handling
+	update_initial_gov_state();
+	LOG_MSG( "governor is set to [%s]\n", get_initial_governor() );
+}
+
+// Called on exit to clean up the governors if appropriate
+void term_game_mode()
+{
+	if( num_games )
+		leave_game_mode();
+}
+
+// Register a game pid with the game mode
+// Will trigger enter game mode if appropriate
+void register_game( int pid )
+{
+	// Check for duplicates
+	for( int i = 0; i < num_games; i++ )
+	{
+		if( game_pids[i] == pid )
+		{
+			LOG_ERROR( "Addition requested for already known process [%i]\n", pid );
+			return;
+		}
+	}
+
+	// Check we've not already hit max
+	if( num_games == MAX_GAMES )
+	{
+		LOG_ERROR( "Max games (%i) reached, could not add [%i]\n", MAX_GAMES, pid );
+		return;
+	}
+
+	// Add the game to the database
+	LOG_MSG( "Adding game: %i\n", pid );
+	game_pids[num_games] = pid;
+	num_games++;
+
+	if( num_games == 1 )
+		enter_game_mode();
+}
+
+// Remove a game from game mode
+// Will exit game mode if appropriate
+void unregister_game( int pid )
+{
+	bool found = false;
+
+	// Check list even contains this entry
+	for( int i = 0; i < num_games; i++ )
+	{
+		if( game_pids[i] == pid )
+		{
+			LOG_MSG( "Removing game: %i\n", pid );
+			memmove( &game_pids[i], &game_pids[i+1], MAX_GAMES - (i+1) );
+			num_games--;
+			found = true;
+		}
+	}
+
+	if( !found )
+	{
+		LOG_ERROR( "Removal requested for unknown process [%i]\n", pid );
+		return;
+	}
+
+	// Leave game mode if needed
+	if( num_games == 0 )
+		leave_game_mode();
+}
+

daemon/gamemode.h

@@ -0,0 +1,43 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _GAME_MODE_GAMEMODE_H_
+#define _GAME_MODE_GAMEMODE_H_
+
+// Initialise or terminate the game mode system
+void init_game_mode();
+void term_game_mode();
+
+// Add or remove games to the tracker
+// Tracker will automatically start and stop game mode as appropriate
+void register_game( int pid );
+void unregister_game( int pid );
+
+#endif // _GAME_MODE_GAMEMODE_H_

daemon/governors.c

@@ -0,0 +1,78 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "governors.h"
+#include "logging.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <linux/limits.h>
+
+static char initial[32];
+
+// Store the initial governor state to be referenced later
+void update_initial_gov_state()
+{
+	static char* command = "cpugovctl get";
+
+	FILE* f = popen( command, "r" );
+	if( !f )
+		FATAL_ERRORNO( "Failed to launch \"%s\" script", command );
+
+	if( !fgets( initial, sizeof(initial)-1, f ) )
+		FATAL_ERROR( "Failed to get output from \"%s\"", command );
+
+	pclose(f);
+
+	strtok( initial, "\n" );
+}
+
+// Sets all governors to a value, if NULL argument provided, will reset them back
+void set_governors( const char* value )
+{
+	const char* newval = value ? value : initial;
+	LOG_MSG("Setting governors to %s\n", newval ? newval : "initial values");
+
+	char command[PATH_MAX] = {};
+	snprintf( command, sizeof(command), "cpugovctl set %s", newval );
+
+	FILE* f = popen( command, "r" );
+	if( !f )
+		FATAL_ERRORNO( "Failed to launch %s script", command );
+
+	pclose(f);
+}
+
+// Return the initial governor
+const char* get_initial_governor()
+{
+	return initial;
+}
+

daemon/governors.h

@@ -0,0 +1,43 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _GOVERNORS_GAMEMODE_H_
+#define _GOVERNORS_GAMEMODE_H_
+
+// Store the initial governor state to be referenced later
+void update_initial_gov_state();
+
+// Get the initial governor state
+const char* get_initial_governor();
+
+// Sets all governors to a value, if null argument provided, will reset them back
+void set_governors( const char* value );
+
+#endif // _GOVERNORS_GAMEMODE_H_

daemon/logging.c

@@ -0,0 +1,48 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "logging.h"
+#include "syslog.h"
+
+static bool use_syslog = false;
+
+// Control if we want to use the system logger
+void set_use_syslog( const char* name )
+{
+	// Open the syslog
+	openlog( name, LOG_PID, LOG_DAEMON );
+	use_syslog = true;
+}
+
+// Simple getter for the syslog var
+bool get_use_syslog()
+{
+	return use_syslog;
+}

daemon/logging.h

@@ -0,0 +1,59 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _LOGGING_GAMEMODE_H_
+#define _LOGGING_GAMEMODE_H_
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+#include <stdbool.h>
+
+// Logging helpers
+#define PLOG_MSG( msg, ... ) printf( msg, ##__VA_ARGS__ )
+#define SYSLOG_MSG( msg, ... ) syslog( LOG_INFO, msg, ##__VA_ARGS__ )
+#define LOG_MSG( msg, ... ) do { if( get_use_syslog() ) SYSLOG_MSG( msg, ##__VA_ARGS__ ); else PLOG_MSG( msg, ##__VA_ARGS__ );  } while(0)
+
+#define PLOG_ERROR( msg, ... ) fprintf( stderr, msg, ##__VA_ARGS__ )
+#define SYSLOG_ERROR( msg, ... ) syslog( LOG_ERR, msg, ##__VA_ARGS__ )
+#define LOG_ERROR( msg, ... ) do { if( get_use_syslog() ) SYSLOG_MSG( msg, ##__VA_ARGS__ ); else PLOG_MSG( msg, ##__VA_ARGS__ );  } while(0)
+
+// Fatal errors trigger an exit
+#define FATAL_ERRORNO( msg, ... ) do { LOG_ERROR( msg " (%s)\n", ##__VA_ARGS__, strerror(errno) ); exit(EXIT_FAILURE); } while(0)
+#define FATAL_ERROR( msg, ... ) do { LOG_ERROR( msg, ##__VA_ARGS__ ); exit(EXIT_FAILURE); } while(0)
+
+// Control if we want to use the system logger
+void set_use_syslog( const char* name );
+bool get_use_syslog();
+
+#endif //_LOGGING_GAMEMODE_H_

daemon/main.c

@@ -0,0 +1,99 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+// Simple daemon to allow user space programs to control the CPU governors
+#include "gamemode.h"
+#include "dbus_messaging.h"
+#include "logging.h"
+#include "daemonize.h"
+
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+
+static void sigint_handler(int signo)
+{
+	LOG_MSG( "Quitting by request...\n" );
+
+	// Terminate the game mode
+	term_game_mode();
+
+	exit( EXIT_SUCCESS );
+}
+
+// Main entry point
+int main( int argc, char *argv[] )
+{
+	// Gather command line options
+	bool daemon = false;
+	bool system_dbus = false;
+	bool use_syslog = false;
+	int opt = 0;
+	while( ( opt = getopt( argc, argv, "dsl") ) != -1 )
+	{
+		switch( opt )
+		{
+			case 'd':
+				daemon = true;
+				break;
+			case 's':
+				system_dbus = true;
+				break;
+			case 'l':
+				use_syslog = true;
+				break;
+			default:
+				fprintf( stderr, "Usage: %s [-d] [-s] [-l]\n", argv[0] );
+				exit( EXIT_FAILURE );
+				break;
+		}
+	}
+
+	// Use syslog if requested
+	if( use_syslog )
+		set_use_syslog( argv[0] );
+
+	// Daemonize ourselves first if asked
+	if ( daemon )
+		daemonize( argv[0] );
+
+	// Set up the game mode
+	init_game_mode();
+
+	// Set up the SIGINT handler
+	if( signal( SIGINT, sigint_handler ) == SIG_ERR )
+		FATAL_ERRORNO( "Could not catch SIGINT" );
+
+	// Run the main dbus message loop
+	run_dbus_main_loop( system_dbus );
+
+	// Log we're finished
+	LOG_MSG( "Quitting naturally...\n" );
+}

data/cpugovctl_perms.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# Allow cpugovctl to control the governors
+chmod +4555 ${MESON_INSTALL_PREFIX}/bin/cpugovctl
+

data/gamemoded.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=gamemoded
+
+[Service]
+Type=dbus
+BusName=com.feralinteractive.GameMode
+ExecStart=/usr/bin/gamemoded -l
+
+[Install]
+WantedBy=default.target

example/main.c

@@ -0,0 +1,48 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include "gamemode_client.h"
+
+#include <unistd.h>
+#include <stdio.h>
+
+int main(){
+	// Request we start game mode
+	if( gamemode_request_start() != 0 )
+		printf( "Failed to request gamemode start: %s...\n", gamemode_error_string() );
+
+	// Simulate running a game
+	sleep( 10 );
+
+	// Request we end game mode (optional)
+	if( gamemode_request_end() != 0 )
+		printf( "Failed to request gamemode end: %s...\n", gamemode_error_string() );
+}
+

lib/client_impl.c

@@ -0,0 +1,97 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <string.h>
+#include <systemd/sd-bus.h>
+
+// Storage for error strings
+static char error_string[512] = {};
+
+// Simple requestor function for a gamemode
+static int gamemode_request( const char* function )
+{
+	sd_bus_message* msg = NULL;
+	sd_bus* bus = NULL;
+
+	int result = -1;
+
+	// Open the user bus
+	int ret = sd_bus_open_user(&bus);
+	if( ret < 0 )
+		snprintf( error_string, sizeof(error_string), "Could not connect to bus: %s", strerror(-ret) );
+	else
+	{
+		// Attempt to send the requested function
+		ret = sd_bus_call_method( bus,
+			"com.feralinteractive.GameMode",
+			"/com/feralinteractive/GameMode",
+			"com.feralinteractive.GameMode",
+			function,
+			NULL,
+			&msg,
+			"i",
+			getpid() );
+		if( ret < 0 )
+			snprintf( error_string, sizeof(error_string), "Could not call method on bus: %s", strerror(-ret) );
+		else
+		{
+			// Read the reply
+			ret = sd_bus_message_read( msg, "i", &result );
+			if( ret < 0 )
+				snprintf( error_string, sizeof(error_string), "Failure to parse response: %s", strerror(-ret) );
+		}
+	}
+
+	return result;
+}
+
+// Get the error string
+extern const char* real_gamemode_error_string()
+{
+	return error_string;
+}
+
+// Wrapper to call RegisterGame
+extern int real_gamemode_request_start()
+{
+	return gamemode_request( "RegisterGame" );
+}
+
+// Wrapper to call UnregisterGame
+extern int real_gamemode_request_end()
+{
+	return gamemode_request( "UnregisterGame" );
+}
+

lib/client_loader.c

@@ -0,0 +1,35 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+
+// Simply include the header with GAMEMODE_AUTO set
+// This will ensure it calls the functions when it's loaded
+#define GAMEMODE_AUTO
+#include "gamemode_client.h"

lib/gamemode_client.h

@@ -0,0 +1,165 @@
+/*
+
+Copyright (c) 2017, Feral Interactive
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+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
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+ */
+#ifndef _CLIENT_GAMEMODE_H_
+#define _CLIENT_GAMEMODE_H_
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include <dlfcn.h>
+#include <errno.h>
+#include <string.h>
+
+char _client_error_string[512] = {};
+
+// Load libgamemode dynamically to dislodge us from most dependencies
+// This allows clients to link and/or use this regardless of runtime
+// See SDL2 for an example of the reasoning behind this in terms of
+// dynamic versioning as well
+int _libgamemode_loaded = 1;
+
+// Typedefs for the functions to load
+typedef int(*_gamemode_request_start)();
+typedef int(*_gamemode_request_end)();
+typedef const char*(*_gamemode_error_string)();
+
+// Storage for functors
+_gamemode_request_start _REAL_gamemode_request_start = NULL;
+_gamemode_request_end   _REAL_gamemode_request_end   = NULL;
+_gamemode_error_string  _REAL_gamemode_error_string  = NULL;
+
+// Loads libgamemode and needed functions
+// returns 0 on success and -1 on failure
+__attribute__((always_inline))
+inline int _load_libgamemode()
+{
+	// We start at 1, 0 is a success and -1 is a fail
+	if ( _libgamemode_loaded != 1 )
+		return _libgamemode_loaded;
+
+	void* libgamemode = NULL;
+
+	// Try and load libgamemode
+	libgamemode = dlopen( "libgamemode.so", RTLD_NOW );
+	if( !libgamemode )
+		snprintf( _client_error_string, sizeof(_client_error_string), "dylopen failed - %s", dlerror() );
+	else
+	{
+		_REAL_gamemode_request_start = (_gamemode_request_start)dlsym( libgamemode, "real_gamemode_request_start" );
+		_REAL_gamemode_request_end   = (_gamemode_request_end)  dlsym( libgamemode, "real_gamemode_request_end" );
+		_REAL_gamemode_error_string  = (_gamemode_error_string) dlsym( libgamemode, "real_gamemode_error_string" );
+
+		// Verify we have the functions we want
+		if( _REAL_gamemode_request_start && _REAL_gamemode_request_end && _REAL_gamemode_error_string )
+		{
+			_libgamemode_loaded = 0;
+			return 0;
+		}
+		else
+			snprintf( _client_error_string, sizeof(_client_error_string), "dlsym failed - %s", dlerror() );
+	}
+
+	_libgamemode_loaded = -1;
+	return -1;
+}
+
+// Redirect to the real libgamemode
+__attribute__((always_inline))
+inline const char* gamemode_error_string()
+{
+	// If we fail to load the system gamemode, return our error string
+	if( _load_libgamemode() < 0 )
+		return _client_error_string;
+
+	return _REAL_gamemode_error_string();
+}
+
+// Redirect to the real libgamemode
+// Allow automatically requesting game mode
+// Also prints errors as they happen
+#ifdef GAMEMODE_AUTO
+__attribute__((constructor))
+#else
+__attribute__((always_inline))
+inline
+#endif
+int gamemode_request_start()
+{
+	// Need to load gamemode
+	if( _load_libgamemode() < 0 )
+	{
+#ifdef GAMEMODE_AUTO
+		fprintf( stderr, "gamemodeauto: %s\n", gamemode_error_string() );
+#endif
+		return -1;
+	}
+
+	if( _REAL_gamemode_request_start() < 0 )
+	{
+#ifdef GAMEMODE_AUTO
+		fprintf( stderr, "gamemodeauto: %s\n", gamemode_error_string() );
+#endif
+		return -1;
+	}
+
+	return 0;
+}
+
+// Redirect to the real libgamemode
+#ifdef GAMEMODE_AUTO
+__attribute__((destructor))
+#else
+__attribute__((always_inline))
+inline
+#endif
+int gamemode_request_end()
+{
+	// Need to load gamemode
+	if( _load_libgamemode() < 0 )
+	{
+#ifdef GAMEMODE_AUTO
+		fprintf( stderr, "gamemodeauto: %s\n", gamemode_error_string() );
+#endif
+		return -1;
+	}
+
+	if( _REAL_gamemode_request_end() < 0 )
+	{
+#ifdef GAMEMODE_AUTO
+		fprintf( stderr, "gamemodeauto: %s\n", gamemode_error_string() );
+#endif
+		return -1;
+	}
+
+	return 0;
+}
+
+#endif // _CLIENT_GAMEMODE_H_

meson.build

@@ -0,0 +1,53 @@
+project('gamemode', 'c',
+	version : '0.1',
+	license : 'BSD' )
+cc = meson.get_compiler('c')
+
+libsystemd = cc.find_library('systemd')
+libdl = cc.find_library('dl')
+
+executable( 'gamemoded',
+	'daemon/main.c',
+	'daemon/gamemode.c',
+	'daemon/logging.c',
+	'daemon/daemonize.c',
+	'daemon/dbus_messaging.c',
+	'daemon/governors.c',
+	dependencies: libsystemd,
+	install: true )
+
+# Main client library to message the daemon
+shared_library( 'gamemode',
+	'lib/client_impl.c',
+	dependencies: libsystemd,
+	install : true )
+
+# install the service file
+install_data( 'data/gamemoded.service', install_dir: '/etc/systemd/user' )
+
+# Small target util to get and set cpu governors
+executable( 'cpugovctl',
+	'daemon/cpugovctl.c',
+	'daemon/logging.c',
+	install : true )
+
+# Give cpugovctl the permissions it needs
+meson.add_install_script( 'data/cpugovctl_perms.sh',
+	dependencies : 'cpugovctl' )
+
+# Small library to automatically use gamemode
+shared_library( 'gamemodeauto',
+	'lib/client_loader.c',
+	dependencies : libdl,
+	install : true )
+
+# Install the gamemode_client header
+install_headers( 'lib/gamemode_client.h' )
+
+# An example game
+libdir = include_directories('lib')
+executable( 'example',
+	'example/main.c',
+	dependencies : libdl,
+	include_directories : libdir )
+