[PATCH 1/2] lib: fwts_uefi: add the function to check the efivars interface existence

[Colin Ian King]

On 17/05/13 13:02, Matt Fleming wrote:
> On Fri, 17 May, at 06:15:04PM, IvanHu wrote:
>> Actually , I found that checking the secure boot variables db and
>> kek via the vars interface will fail.
>> using hexdump and cat for these variables also failed,
>> u at u-HP-Pavilion-m4-Notebook-PC:/sys/firmware$ sudo hexdump
>> efi/vars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f/data hexdump:
>> efi/vars/db-d719b2cb-3d3a-4596-a3bc-dad00e67656f/data: Input/output
>> error
>> ,but efivars works fine. That's why I add the patches to specify
>> using efivars interface for running the securebootcert test to avoid
>> the unintentional fail from using vars interface.
> 
> The issue you may be running into here is that the old EFI variable
> sysfs interface cannot handle variables that are larger than 1024 bytes.
> This is in fact the reason that the efivarfs file system was created -
> to address this limitation.
> 

Matt, so is it the case that while the old sysfs interface valid, it
should probably be avoided?