[systemd-devel] EXT :Re: Systemd udev add tag for boot device

[Boyce, Kevin P. (AS)]

Thank you Lennart.

I'm thinking I will create my own sort of "built-in" command that can 
parse /proc/cmdline to look for the root= variable early in udev rules 
so I can create the tag.

Kevin

On 1/13/20 4:42 AM, Lennart Poettering wrote:
> eOn Fr, 06.12.19 14:35, Boyce, Kevin P [US] (AS) (Kevin.Boyce at ngc.com) wrote:
>
>> Good Morning List,
>>
>> Does anyone know of a good way to use udev to set a TAG property on every partition of a disk  that was used to boot the system?
>>
>> In other words, I want a udev rule that adds a TAG to every
>> partition on the same disk /boot was found on containing the running
>> kernel and intiramfs.
> On EFI systems with compliant GPT boot loaders
> systemd-gpt-auto-generator implements something like that.
>
> But in the general case: the information which boot device was used is
> not available, unless the boot loader explicitly passes this
> information somewhow.
>
> We generally recommend that EFI boot loaders at least pass this
> information via the LoaderDevicePartUUID EFI variable, see this spec
> for details:
>
> https://systemd.io/BOOT_LOADER_INTERFACE
>
> For non-EFI there's no spec like this, since there's no generic way to
> pass arbitrary data from boot loader to OS, sorry.
>
> Lennart
>
> --
> Lennart Poettering, Berlin