reboot: Add sanity checking of write to nextboot.conf

[imp]

Summary

Add sanity checking to the write to nextboot. Move to separate function
and allow force to override all errors. If we can't write nextboot.conf,
don't silently fail anymore.

Sponsored by: Netflix

[kib]

sbin/reboot/reboot.c

77

Since you use asprintf() anyway, why not use stdio to write the nextboot.conf? IMO it would trim a lot of convoluted code.

[imp]

update per kib to use stdio directly.

[imp]

rebase / refresh

[markj]

Not a problem with this revision, but does this functionality work at all on ZFS? There's no use of zfsbootcfg.

sbin/reboot/reboot.c

92

Extra newline.

[imp]

In D43803#999837, @markj wrote:

Not a problem with this revision, but does this functionality work at all on ZFS? There's no use of zfsbootcfg.

See later changes in the series. I may have forgotten to include you on all of them.

[markj]

In D43803#999837, @markj wrote:

Not a problem with this revision, but does this functionality work at all on ZFS? There's no use of zfsbootcfg.

Never mind, I see the later patches in the series.

[kevans]

sbin/reboot/reboot.c

83

Would perhaps be a bit more consistent

[imp]

sbin/reboot/reboot.c

83

I overlooked this before I pushed. You are correct.