populate_string_buffer
ret = populate_string_buffer(start, a_name_size, a_name);
ret = populate_string_buffer(start, a_value_size, a_value);
ssize_t populate_string_buffer(char *buffer, size_t buffer_len, const char *str);
ret = populate_string_buffer(start, password_type_size, password_type);
ret = populate_string_buffer(start, current_password_size, current_password);
ret = populate_string_buffer(start, new_size, new);