gamemode-context: Ignore Steam client processes

If you want to run your whole Steam client under gamemode to not adjust
each game individually, we certainly should leave the Steam client
processes alone as we don't want them to take resources away from the
game. Otherwise, Steam client processes may run with `SCHED_ISO`.

Closes: FeralInteractive#67
Signed-off-by: Kai Krakow <kai@kaishome.de>

daemon/gamemode-context.c

@@ -581,10 +581,19 @@ int game_mode_context_register(GameModeContext *self, pid_t client, pid_t reques
 		goto error_cleanup;
 
 	/* Check for forced exceptions */
+	char *exe = NULL;
 	if (strstr(executable, "/wineserver") != NULL) {
 		/* wineserver from wine-staging has its own means of setting priorities */
 		LOG_MSG("Client [%s] was rejected (forced to ignore wineserver)\n", executable);
 		goto error_cleanup;
+	} else if (((exe = strstr(executable, "/steam")) != NULL) && (strlen(exe) == 6)) {
+		/* we don't want to touch steam if the whole steam client runs in gamemode */
+		LOG_MSG("Client [%s] was rejected (forced to ignore steam)\n", executable);
+		goto error_cleanup;
+	} else if (strstr(executable, "/steamwebhelper") != NULL) {
+		/* we don't want to touch steamwebhelper if the whole steam client runs in gamemode */
+		LOG_MSG("Client [%s] was rejected (forced to ignore steamwebhelper)\n", executable);
+		goto error_cleanup;
 	}
 
 	/* Check our blacklist and whitelist */