if executing command below yields: The system has no more ptys.
1 | expect -c "spawn passwd root" |
we can check whether /dev/ptmx exists, if not, just create it:
1 2 | mknod /dev/ptmx c 5 2 chmod 666 /dev/ptmx |
refer to:
https://www.linuxfromscratch.org/lfs/faq.html#no-ptys