dbg("read sbbuf len:0x%llx", (unsigned long long) (off + len));
lseek(id->fd, 0, SEEK_SET);
buf_len = read(id->fd, id->sbbuf, off + len);
dbg("read sbbuf len:0x%llx", (unsigned long long) (off + len));
lseek(id->fd, 0, SEEK_SET);
buf_len = read(id->fd, id->sbbuf, off + len);