Refactor to store the initial governor state when gamemode is entered

Rather than when gamemoded is started. As see in Issue #52.

	A small refactor here to ensure things stay consistent, especially
	to stop storing a pointer from get_gov_state that might have had
	it's memory changed at some point, confusingly.

CHANGELOG

@@ -1,3 +1,7 @@
+1.2
+
+Store the initial governor state on mode enter
+
 1.1
 
 Cascaded config file loading

daemon/gamemode.c

@@ -33,6 +33,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "gamemode.h"
 #include "daemon_config.h"
+#include "governors-query.h"
 #include "governors.h"
 #include "logging.h"
 
@@ -60,7 +61,7 @@ struct GameModeContext {
 
 	GameModeConfig *config; /**<Pointer to config object */
 
-	bool performance_mode; /**<Only updates when we can */
+	char initial_cpu_mode[64]; /**<Only updates when we can */
 
 	/* Reaper control */
 	struct {
@@ -99,14 +100,13 @@ void game_mode_context_init(GameModeContext *self)
 	had_context_init = true;
 	self->refcount = ATOMIC_VAR_INIT(0);
 
+	/* clear the initial string */
+	memset(self->initial_cpu_mode, 0, sizeof(self->initial_cpu_mode));
+
 	/* Initialise the config */
 	self->config = config_create();
 	config_init(self->config);
 
-	/* 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());
-
 	pthread_rwlock_init(&self->rwlock, NULL);
 	pthread_mutex_init(&self->reaper.mutex, NULL);
 	pthread_cond_init(&self->reaper.condition, NULL);
@@ -176,8 +176,20 @@ static void game_mode_context_enter(GameModeContext *self)
 		i++;
 	}
 
-	if (!self->performance_mode && set_governors("performance")) {
-		self->performance_mode = true;
+	/* Read the initial governor state so we can revert it correctly */
+	const char *initial_state = get_gov_state();
+	if (initial_state) {
+		/* store the initial cpu governor mode */
+		strncpy(self->initial_cpu_mode, initial_state, sizeof(self->initial_cpu_mode) - 1);
+		self->initial_cpu_mode[sizeof(self->initial_cpu_mode) - 1] = '\0';
+		LOG_MSG("governor was initially set to [%s]\n", initial_state);
+
+		/* set the governor to performance */
+		if (!set_governors("performance")) {
+			/* if the set fails, clear the initial mode so we don't try and reset it back and fail
+			 * again, presumably */
+			memset(self->initial_cpu_mode, 0, sizeof(self->initial_cpu_mode));
+		}
 	}
 }
 
@@ -192,8 +204,10 @@ static void game_mode_context_leave(GameModeContext *self)
 	LOG_MSG("Leaving Game Mode...\n");
 	sd_notifyf(0, "STATUS=%sGameMode is currently deactivated.%s\n", "\x1B[1;36m", "\x1B[0m");
 
-	if (self->performance_mode && set_governors(NULL)) {
-		self->performance_mode = false;
+	/* Reset the governer state back to initial */
+	if (self->initial_cpu_mode[0] != '\0') {
+		set_governors(self->initial_cpu_mode);
+		memset(self->initial_cpu_mode, 0, sizeof(self->initial_cpu_mode));
 	}
 
 	char scripts[CONFIG_LIST_MAX][CONFIG_VALUE_MAX];

daemon/governors-query.c

@@ -99,8 +99,9 @@ int fetch_governors(char governors[MAX_GOVERNORS][MAX_GOVERNOR_LENGTH])
  */
 const char *get_gov_state(void)
 {
-	/* Cached primary governor state */
+	/* Persistent governor state */
 	static char governor[64] = { 0 };
+	memset(governor, 0, sizeof(governor));
 
 	/* State for all governors */
 	char governors[MAX_GOVERNORS][MAX_GOVERNOR_LENGTH] = { { 0 } };

daemon/governors.c

@@ -41,16 +41,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include <sys/wait.h>
 #include <unistd.h>
 
-static const char *initial = NULL;
-
-/**
- * Cache the governor state as seen at startup
- */
-void update_initial_gov_state(void)
-{
-	initial = get_gov_state();
-}
-
 /**
  * Update the governors to the given argument, via pkexec
  */
@@ -61,12 +51,11 @@ bool set_governors(const char *value)
 	int ret = 0;
 	int r = -1;
 
-	const char *const govern = value ? value : initial;
 	const char *const exec_args[] = {
-		"/usr/bin/pkexec", LIBEXECDIR "/cpugovctl", "set", govern, NULL,
+		"/usr/bin/pkexec", LIBEXECDIR "/cpugovctl", "set", value, NULL,
 	};
 
-	LOG_MSG("Requesting update of governor policy to %s\n", govern);
+	LOG_MSG("Requesting update of governor policy to %s\n", value);
 
 	if ((p = fork()) < 0) {
 		LOG_ERROR("Failed to fork(): %s\n", strerror(errno));
@@ -102,11 +91,3 @@ bool set_governors(const char *value)
 
 	return true;
 }
-
-/**
- * Return the cached governor seen at startup
- */
-const char *get_initial_governor(void)
-{
-	return initial;
-}

daemon/governors.h

@@ -33,16 +33,6 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include <stdbool.h>
 
-/**
- * Store initial governor so we can use it again
- */
-void update_initial_gov_state(void);
-
-/**
- * Return the governer set in update_initial_gov_state
- */
-const char *get_initial_governor(void);
-
 /**
  * Update all governors to the given value. If this is NULL, restore the
  * initial governor.