[systemd-devel] implementation status of http://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/ ?

[Kay Sievers]

On Tue, Jun 11, 2013 at 11:14 PM, Colin Walters <walters at verbum.org> wrote:
> On Tue, 2013-06-04 at 15:30 +0200, Lennart Poettering wrote:
>> On Mon, 03.06.13 19:10, Colin Walters (walters at verbum.org) wrote:
>>
>> > What's the implementation status of
>> > http://www.freedesktop.org/wiki/Specifications/BootLoaderSpec/ ?
>> >
>> > For example, do any patches exist for grub or syslinux to read
>> > from /boot/loader (either at runtime or to generate a bootloader-native
>> > config file statically?)
>> >
>> > I'm aware gummiboot does (and its wiki page should probably crosslink
>> > with the above).  But any others?
>>
>> The Grub patch I did (that Kay linked exists), but this isn't polished
>> and fully integrated into Fedora yet.
>
> The question I had looking at this is: what determines the ordering?  I
> guess it's intended to be the version field, but what if I have both
> Debian and Fedora installed, the default comes down to whichever has a
> newer kernel?

Gummiboot does have a config file which contains a pattern match,
which carries the machine-id, it will always pick the latest kernel
for that given machine:
  $ sudo cat /boot/loader/loader.conf
  #timeout 3
  default 6a9857a393724b7a981ebb5b8495b9ea-*

> Or should bootloaders only use the version field to sort within say a
> given machine-id, and retain their own custom config files for global
> ordering?  That'd make the most sense to me.

Right, that part is not specified in the spec.

> BTW, there is quite a lot of semantics that comes with the phrase
> "Debian-style version sorts".  gummiboot appears to use "strverscmp"
> from glibc, but that doesn't do the "~" character for example.

I think glibc's version is more complex, isn't it? I don't know
exactly where gummiboot's version is coming from, might be just the
simplest working version:
  http://cgit.freedesktop.org/gummiboot/tree/src/efi/gummiboot.c#n984

Kay