Use safer string copying in gui for file list

stm-firmware/ui/gui.c

@@ -374,6 +374,36 @@ static void gui_menu_constant_temperature_driver(struct lcd_menu *menu, enum men
 
 }
 
+/**
+ * @brief A safe strncpy which ensures thtat the copied string ends in a null character
+ * @param dest Destiantion ptr
+ * @param src Source pointer
+ * @param max_size maximum size of the destination (including null terminator)
+ * @return 0 if successful, positive, if string was to short to hold all data, negative if parameter error
+ */
+static int safe_strncpy(char *dest, const char *src, size_t max_size) {
+	size_t idx;
+	bool terminated = false;
+
+	if (!dest || !src || !max_size)
+		return -1000;
+
+	for (idx = 0; idx < max_size; idx++) {
+		dest[idx] = src[idx];
+		if (src[idx] == '\0') {
+			terminated = true;
+			break;
+		}
+	}
+
+	if (!terminated) {
+		dest[max_size - 1] = 0;
+		return 1;
+	}
+
+	return 0;
+}
+
 /**
  * @brief load_temperature_file_list_from_sdcard
  * @return -1 File error, 0 successful
@@ -385,6 +415,7 @@ static int load_temperature_file_list_from_sdcard(char (*list)[17], uint32_t len
 	FILINFO finfo;
 	FRESULT fres;
 
+
 	if (!list)
 		return -1001;
 
@@ -399,7 +430,7 @@ static int load_temperature_file_list_from_sdcard(char (*list)[17], uint32_t len
 	fres = f_findfirst(&directory, &finfo, "/", "*.tpr");
 	i = 0;
 	while (fres == FR_OK && finfo.fname[0]) {
-		strncpy(list[i], finfo.fname, sizeof(*list));
+		safe_strncpy(&list[i][0], finfo.fname, sizeof(*list));
 		fres = f_findnext(&directory, &finfo);
 		i++;
 		if (i >= len)