[syslinux] [PATCH] : Adding dlabel option to chain.c32

[Michal Soltys]

On 2016-06-30 19:41, Erwan Velu via Syslinux wrote:
> The exisiting label= option offer to boot on a gpt partition that have
> a particular label.
> The existing guuid= option offer to boot on a disk or partition with a
> particular label.
> 
> This new option offer to boot the disk that have a partition which
> have a given label.
> The label is so just a way to detect a disk to boot.
> 
> A typical use is for making an intelligent localboot like :
> 
>     label localboot
>         com32 chain.c32
>         append dlabel=datapartition
> 
> This allow booting on a disk that sports a least one partition
> labelled "datapartition".
> 
> You can consider dlabel= doing almost what mbr= does but by inspecting
> the gpt partitions label.
> 

Btw, I'm fine with the patch (functionally). As for the name for the
option I'm not sure (and I can see it spawned lots of discussion).

To not keep it too long, maybe something like

diskbypname

or

diskbyplabel

(or even both available)

As for the patch, I'd change one comment:

Return drive and iterator at proper position.

to

Return drive and iterator at 0th position.

To follow the same "scheme" as in find_by_sig(). And move the code under
that function maybe (so stuff returning drive is in one place). It's
just nitpicking though.

For the record, the whole iterator stuff is missing one thing I've had
patch prepared a while ago (but I've been stomped with RL stuff for a
while ...) that would also allow choosing GPT drive by MBR sig; gotta
dig it up and test at some point. Not sure if that would be useful for
you (or anyone ;) ).