[parted-devel] [PATCH] More correct handling of the HeaderSize field in GPT labels

[Otavio Salvador]

"Matthew S. Harris" <mharris312 at gmail.com> writes:

> On 7/8/07, Otavio Salvador <otavio at debian.org> wrote:
>> "Matthew S. Harris" <mharris312 at gmail.com> writes:
>>
>> > In general, if there end up being multiple, backwards-compatible
>> > versions of the EFI spec, then Parted should be able to operate on the
>> > set of headers it knows about and ignore the rest.
>>
>> That's the major issue. I personally dislike to believe on that.
>
> I see.  Is your concern that changes to the EFI spec won't be
> backwards-compatible, or that Parted will not be careful enough in its
> handling of the part of the header it doesn't understand?

I think if there're things we're not aware of we ought to abort
instead of continue the work and _guess_ it'll work properly. Think if
something would be need to be changed on those "new headers" to the
system work properly and due it we might break a user system.

>> > In this case, the EFI spec shows a table of the fields in the header,
>> > and it includes as the last "field" all the remaining space in the
>> > block.  OpenSolaris interprets this to mean that HeaderSize is the
>> > size of the block; Parted obviously does not.  This is significant
>> > because the CRC of the header is supposed to be of HeaderSize bytes.
>> > That's why this change is needed.
>>
>> Sorry but I didn't get what you mean by the way of OpenSolaris to
>> work.
>>
>> You mean that OpenSolaris cannot check the CRC since it interprets the
>> size wrongly, is it?
>
> No, I mean that Parted cannot check the CRC of an OpenSolaris
> partition because Parted uses a constant rather than the value of
> HeaderSize in the disk label to determine how many bytes to compute
> the CRC over.

Isn't it a bug then?

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