Description
System information
| Type | Version/Name |
|---|---|
| Distribution Name | Void Linux |
| Distribution Version | rolling release |
| Linux Kernel | 5.9.3 |
| Architecture | x86_64 |
| ZFS Version | 2.0.0-rc5 |
| SPL Version | 2.0.0-rc5 |
Describe the problem you're observing
When building an initramfs using dracut, I get errors in the part where it calls zgenhostid:
# Synchronize initramfs and system hostid
zgenhostid -o "${initdir}/etc/hostid" "$(hostid)"
Since current musl versions implement gethostid(3), which is what hostid(1) uses, as a stub that returns 0, this command fails, because zgenhostid.c has a check for that argument, which rejects any value smaller than 1: if (input_i < 0x1 || input_i > UINT32_MAX) {.
I have a patch in the musl ML for implementing the behavior where gethostid(3) reads /etc/hostid, but that hasn't been merged yet, and any systems that don't have latest musl will still be affected.
I checked the final initramfs, and it doesn't have a /etc/hostid file.
Describe how to reproduce the problem
Generate an initramfs using dracut in a musl based system with ZFS versions after 9cc177b.
Include any warning/errors/backtraces from the system logs
The dracut command printed out the help text for zgenhostid, since the error path includes a call to usage().
Possible solutions
The zfs module for dracut before 9cc177b still did the wrong thing on musl, since it would end up with a zeroed out /etc/hostid in the initramfs; but it still managed to write the file into the initramfs and didn't pollute the initramfs tool output with error messages from zgenhostid. If we want to return to this state, it would be enough to simply allow input_i in zgenhostid.c to be 0.
Otherwise, zgenhostid could be extended to read /etc/hostid itself or the initramfs generation could copy /etc/hostid from the host system if it exists. The disadvantage here is that it will be a workaround for a musl limitation that should be solved at some point in the future.
I am open to discussing possible solutions and fixes, including making PRs for them.