MAX_INPUT_BUF_SZ
char input_buf[MAX_INPUT_BUF_SZ];
memset(input_buf, 0, MAX_INPUT_BUF_SZ);
if (copy_from_user(input_buf, buf, min_t(size_t, count, MAX_INPUT_BUF_SZ)))
input_buf[MAX_INPUT_BUF_SZ - 1] = '\0';
char file_path[MAX_INPUT_BUF_SZ];