Fix multiple memory issues with the help of asan

Fix buffer overflows and memory leaks.

cg.c

@@ -55,8 +55,10 @@ bool cg_get_metrics(int no, struct cg_metrics *dst)
 		break;
 	default:
 		WARNING("Unknown CG type (CG %d)", no);
+		ald_free_data(dfile);
 		return false;
 	}
+	ald_free_data(dfile);
 	return true;
 }
 
@@ -68,6 +70,7 @@ void _cg_free(struct cg *cg)
 		if (cg->pixel_alloc)
 			free(cg->s->pixels);
 		SDL_FreeSurface(cg->s);
+		SDL_DestroyTexture(cg->t);
 	}
 }
 

page.c

@@ -56,7 +56,7 @@ struct page *_alloc_page(int nr_vars)
 void free_page(struct page *page)
 {
 	int cache_no = page->nr_vars - 1;
-	if (cache_no >= NR_CACHES || page_cache[cache_no].cached >= CACHE_SIZE) {
+	if (cache_no < 0 || cache_no >= NR_CACHES || page_cache[cache_no].cached >= CACHE_SIZE) {
 		free(page);
 		return;
 	}

sact_graphics.c

@@ -254,6 +254,7 @@ int sact_SP_SetCG(int sp_no, int cg_no)
 		WARNING("Failed to create sprite");
 		return 0;
 	}
+	cg_reinit(sp->cg);
 	if (!cg_load(sp->cg, cg_no - 1))
 		return 0;
 	sp->rect.w = sp->cg->s->w;

savedata.c

@@ -267,6 +267,7 @@ static union vm_value json_to_vm_value(enum ain_data_type type, enum ain_data_ty
 		}
 		rank = get_json_array_rank(json, &dims);
 		heap[slot].page = alloc_array(rank, dims, array_type(type), struct_type, false);
+		free(dims);
 		load_page(heap[slot].page, json);
 		return vm_int(slot);
 	case AIN_REF_TYPE:
@@ -295,7 +296,8 @@ static cJSON *read_save_file(const char *filename)
 	len = ftell(f);
 	fseek(f, 0, SEEK_SET);
 
-	buf = xmalloc(len);
+	buf = xmalloc(len+1);
+	buf[len] = '\0';
 	if (fread(buf, len, 1, f) != 1) {
 		WARNING("Failed to read save file: %s", filename);
 		free(buf);

sdl_video.c

@@ -39,6 +39,7 @@ int sdl_initialize(void)
 
 	sdl.renderer = SDL_CreateRenderer(sdl.window, -1, 0);
 	sdl_set_window_size(config.view_width, config.view_height);
+	atexit(sdl_remove);
 	return 0;
 }
 
@@ -48,7 +49,9 @@ void sdl_remove(void)
 		return;
 
 	SDL_DestroyRenderer(sdl.renderer);
+	SDL_FreeFormat(sdl.format);
 	SDL_Quit();
+	sdl.window = NULL;
 }
 
 void sdl_fullscreen(bool on)

system4.c

@@ -128,6 +128,7 @@ static void init_gamedata_dir(const char *path)
 	if (ald_count[ALDFILE_WAVE] > 0)
 		ald_init(ALDFILE_WAVE, ald_filenames[ALDFILE_WAVE], ald_count[ALDFILE_WAVE]);
 
+	closedir(dir);
 }
 
 static char *get_xsystem4_home(void)
@@ -150,7 +151,7 @@ static char *get_xsystem4_home(void)
 	// $HOME/.xsystem4
 	env_home = getenv("HOME");
 	if (env_home && *env_home) {
-		char *home = xmalloc(strlen(env_home) + strlen("/.xsystem4"));
+		char *home = xmalloc(strlen(env_home) + strlen("/.xsystem4") + 1);
 		strcpy(home, env_home);
 		strcat(home, "/.xsystem4");
 		return home;
@@ -165,11 +166,10 @@ static char *get_save_path(const char *dir_name)
 	if (!dir_name)
 		dir_name = "SaveData";
 
-	const char *home = get_xsystem4_home();
 	char *utf8_game_name = sjis2utf(config.game_name, strlen(config.game_name));
 	char *utf8_dir_name = sjis2utf(dir_name, strlen(dir_name));
-	char *save_dir = xmalloc(strlen(home) + 1 + strlen(utf8_game_name) + 1 + strlen(utf8_dir_name) + 1);
-	strcpy(save_dir, home);
+	char *save_dir = xmalloc(strlen(config.home_dir) + 1 + strlen(utf8_game_name) + 1 + strlen(utf8_dir_name) + 1);
+	strcpy(save_dir, config.home_dir);
 	strcat(save_dir, "/");
 	strcat(save_dir, utf8_game_name);
 	strcat(save_dir, "/");