kexec-select-boot: Find a way to not search whole partition

[paulmenzel]

With devices, where /boot is not on a separate partition, but also on the / partition, the find call takes a very long time.

  for i in `find $bootdir -name "$config"`; do
          kexec-parse-boot "$bootdir" "$i" >> $option_file
  done

Passing -b /boot/boot does not work, as the Linux image is only searched in /boot.

No idea, what an elegant solution would be. Maybe the path to /boot/grub (/boot/boot/grub) should be made configurable?

[rminnich]

how long is long? What is the media? is this an intrinsic issue with traversing the file system or is find slow?

[paulmenzel]

Am 08.09.2018 um 18:09 schrieb ron minnich:

how long is long? What is the media?

It’s a 64 GB AHCI SSD connected over SATA. I just rebooted after waiting ten seconds. I did not try the 1 TB HDD yet.

is this an intrinsic issue with traversing the file system or is find slow?

I’d say it’s wrong to search anything else then the files, under `/boot` (in the end file system, not initramfs).

[flammit]

Thanks @paulmenzel! The searching was set to be quite permissive because of the wide variation of boot config files on install/live distro ISOs. Agree though that on the fixed media devices we can be much more selective and assume grub/freedesktop style paths

[merge]

while finding boot options is slow in this case, it's more extreme when it comes to hashing. hashing the whole system is not desired in this case.

[Thrilleratplay]

/boot is assumed to be the boot partition. It is not the most elegant but what about where ever kexec-select-boot passes in /boot replace it with a variable and check if there

bootdir= "/boot"
if [ -d "/boot/boot/" ]; then
  bootdir= "/boot/boot"
fi
kexec-select-boot -m -b "$bootdir" -c "grub.cfg"

There a few places where checking for the specific boot directory would be useful like the oem factory reset where all files in are run through sha256sum

https://github.com/osresearch/heads/blob/master/initrd/bin/oem-factory-reset#L122