Add support for user defined local script plugins

	A much requested feature, this allows for providing custom scripts in the config file. An example in the man page is below and would trigger both a system notification, and allow control over a background crypto mining script automatically in gamemode.

	[custom]
	; Custom scripts (executed using the shell) when gamemode starts and ends
	start=notify-send "GameMode started"
	    /home/me/bin/stop_ethmining.sh

	end=notify-send "GameMode ended"
	    /home/me/bin/start_ethmining.sh

	Scripts are run with system() and do not have any special privilages, as with the rest of the daemon, custom scripts that require root will need their own permissions set up externally.

	This commit also renames two defines as they needed to be moved to the public interface.

README.md

@@ -93,7 +93,6 @@ clang-format -i $(find . -name '*.[ch]')
 
 ### Planned Features
 * Additional mode-switch plugins
-* User configuration for local mode-switch plugins
 * Improved client state tracking (PID is unreliable)
 * API to query if game mode is active
 

daemon/daemon_config.c

@@ -45,15 +45,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #define CONFIG_NAME "gamemode.ini"
 #define CONFIG_DIR "/usr/share/gamemode/"
 
-/* Maximum values in a config list */
-#define MAX_LIST_VALUES 32
-
-/*
- * Maximum length of values in a config list
- * In practice inih has a INI_MAX_LINE value of 200, so this should never get hit
- */
-#define MAX_LIST_VALUE_LENGTH 256
-
 /* Default value for the reaper frequency */
 #define DEFAULT_REAPER_FREQ 5
 
@@ -66,8 +57,11 @@ struct GameModeConfig {
 	int inotfd;
 	int inotwd;
 
-	char whitelist[MAX_LIST_VALUES][MAX_LIST_VALUE_LENGTH];
-	char blacklist[MAX_LIST_VALUES][MAX_LIST_VALUE_LENGTH];
+	char whitelist[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
+	char blacklist[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
+
+	char startscripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
+	char endscripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
 
 	long reaper_frequency;
 };
@@ -76,20 +70,20 @@ struct GameModeConfig {
  * Add values to a char list
  */
 static bool append_value_to_list(const char *list_name, const char *value,
-                                 char list[MAX_LIST_VALUES][MAX_LIST_VALUE_LENGTH])
+                                 char list[CONFIG_LIST_MAX][CONFIG_VALUE_MAX])
 {
 	unsigned int i = 0;
-	while (*list[i] && ++i < MAX_LIST_VALUES)
+	while (*list[i] && ++i < CONFIG_LIST_MAX)
 		;
 
-	if (i < MAX_LIST_VALUES) {
-		strncpy(list[i], value, MAX_LIST_VALUE_LENGTH);
+	if (i < CONFIG_LIST_MAX) {
+		strncpy(list[i], value, CONFIG_VALUE_MAX);
 
-		if (list[i][MAX_LIST_VALUE_LENGTH - 1] != '\0') {
+		if (list[i][CONFIG_VALUE_MAX - 1] != '\0') {
 			LOG_ERROR("Config: Could not add [%s] to [%s], exceeds length limit of %d\n",
 			          value,
 			          list_name,
-			          MAX_LIST_VALUE_LENGTH);
+			          CONFIG_VALUE_MAX);
 
 			memset(list[i], 0, sizeof(list[i]));
 			return false;
@@ -98,7 +92,7 @@ static bool append_value_to_list(const char *list_name, const char *value,
 		LOG_ERROR("Config: Could not add [%s] to [%s], exceeds number of %d\n",
 		          value,
 		          list_name,
-		          MAX_LIST_VALUES);
+		          CONFIG_LIST_MAX);
 		return false;
 	}
 
@@ -146,6 +140,13 @@ static int inih_handler(void *user, const char *section, const char *name, const
 		if (strcmp(name, "reaper_freq") == 0) {
 			valid = get_long_value(name, value, &self->reaper_frequency);
 		}
+	} else if (strcmp(section, "custom") == 0) {
+		/* Custom subsection */
+		if (strcmp(name, "start") == 0) {
+			valid = append_value_to_list(name, value, self->startscripts);
+		} else if (strcmp(name, "end") == 0) {
+			valid = append_value_to_list(name, value, self->endscripts);
+		}
 	}
 
 	if (!valid) {
@@ -167,6 +168,8 @@ static void load_config_file(GameModeConfig *self)
 	/* Clear our config values */
 	memset(self->whitelist, 0, sizeof(self->whitelist));
 	memset(self->blacklist, 0, sizeof(self->blacklist));
+	memset(self->startscripts, 0, sizeof(self->startscripts));
+	memset(self->endscripts, 0, sizeof(self->endscripts));
 	self->reaper_frequency = DEFAULT_REAPER_FREQ;
 
 	/* try locally first */
@@ -252,7 +255,7 @@ bool config_get_client_whitelisted(GameModeConfig *self, const char *client)
 		 * Currently is a simple strstr check, but could be modified for wildcards etc.
 		 */
 		found = false;
-		for (unsigned int i = 0; i < MAX_LIST_VALUES && self->whitelist[i][0]; i++) {
+		for (unsigned int i = 0; i < CONFIG_LIST_MAX && self->whitelist[i][0]; i++) {
 			if (strstr(client, self->whitelist[i])) {
 				found = true;
 			}
@@ -277,7 +280,7 @@ bool config_get_client_blacklisted(GameModeConfig *self, const char *client)
 	 * Currently is a simple strstr check, but could be modified for wildcards etc.
 	 */
 	bool found = false;
-	for (unsigned int i = 0; i < MAX_LIST_VALUES && self->blacklist[i][0]; i++) {
+	for (unsigned int i = 0; i < CONFIG_LIST_MAX && self->blacklist[i][0]; i++) {
 		if (strstr(client, self->blacklist[i])) {
 			found = true;
 		}
@@ -303,3 +306,33 @@ long config_get_reaper_thread_frequency(GameModeConfig *self)
 	pthread_rwlock_unlock(&self->rwlock);
 	return value;
 }
+
+/*
+ * Get a set of scripts to call when gamemode starts
+ */
+void config_get_gamemode_start_scripts(GameModeConfig *self,
+                                       char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX])
+{
+	/* Take the read lock */
+	pthread_rwlock_rdlock(&self->rwlock);
+
+	memcpy(scripts, self->startscripts, sizeof(self->startscripts));
+
+	/* release the lock */
+	pthread_rwlock_unlock(&self->rwlock);
+}
+
+/*
+ * Get a set of scripts to call when gamemode ends
+ */
+void config_get_gamemode_end_scripts(GameModeConfig *self,
+                                     char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX])
+{
+	/* Take the read lock */
+	pthread_rwlock_rdlock(&self->rwlock);
+
+	memcpy(scripts, self->endscripts, sizeof(self->startscripts));
+
+	/* release the lock */
+	pthread_rwlock_unlock(&self->rwlock);
+}

daemon/daemon_config.h

@@ -32,6 +32,13 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <stdbool.h>
 
+/*
+ * Maximum sizes values in a config list
+ * In practice inih has a INI_MAX_LINE value of 200 so the length is just a safeguard
+ */
+#define CONFIG_LIST_MAX 32
+#define CONFIG_VALUE_MAX 256
+
 /*
  * Opaque config context type
  */
@@ -75,3 +82,14 @@ bool config_get_client_blacklisted(GameModeConfig *self, const char *client);
  * Get the frequency (in seconds) for the reaper thread
  */
 long config_get_reaper_thread_frequency(GameModeConfig *self);
+
+/*
+ * Get a set of scripts to call when gamemode starts
+ */
+void config_get_gamemode_start_scripts(GameModeConfig *self,
+                                       char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX]);
+/*
+ * Get a set of scripts to call when gamemode ends
+ */
+void config_get_gamemode_end_scripts(GameModeConfig *self,
+                                     char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX]);

daemon/gamemode.c

@@ -161,6 +161,21 @@ static void game_mode_context_enter(GameModeContext *self)
 	LOG_MSG("Entering Game Mode...\n");
 	sd_notifyf(0, "STATUS=%sGameMode is now active.%s\n", "\x1B[1;32m", "\x1B[0m");
 
+	char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
+	memset(scripts, 0, sizeof(scripts));
+	config_get_gamemode_start_scripts(self->config, scripts);
+
+	unsigned int i = 0;
+	while (*scripts[i] != '\0' && i < CONFIG_LIST_MAX) {
+		LOG_MSG("Executing script [%s]\n", scripts[i]);
+		int err;
+		if ((err = system(scripts[i])) != 0) {
+			/* Log the failure, but this is not fatal */
+			LOG_ERROR("Script [%s] failed with error %d\n", scripts[i], err);
+		}
+		i++;
+	}
+
 	if (!self->performance_mode && set_governors("performance")) {
 		self->performance_mode = true;
 	}
@@ -180,6 +195,21 @@ static void game_mode_context_leave(GameModeContext *self)
 	if (self->performance_mode && set_governors(NULL)) {
 		self->performance_mode = false;
 	}
+
+	char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];
+	memset(scripts, 0, sizeof(scripts));
+	config_get_gamemode_end_scripts(self->config, scripts);
+
+	unsigned int i = 0;
+	while (*scripts[i] != '\0' && i < CONFIG_LIST_MAX) {
+		LOG_MSG("Executing script [%s]\n", scripts[i]);
+		int err;
+		if ((err = system(scripts[i])) != 0) {
+			/* Log the failure, but this is not fatal */
+			LOG_ERROR("Script [%s] failed with error %d\n", scripts[i], err);
+		}
+		i++;
+	}
 }
 
 /**

data/gamemoded.1

@@ -86,6 +86,14 @@ reaper_freq=10
 ; Gamemode will always reject anything in the blacklist
 blacklist=HalfLife3
     glxgears
+
+[custom]
+; Custom scripts (executed using the shell) when gamemode starts and ends
+start=notify-send "GameMode started"
+    /home/me/bin/stop_ethmining.sh
+
+end=notify-send "GameMode ended"
+    /home/me/bin/start_ethmining.sh
 .fi
 .RE