[PATCH] efi_loader: silence 'Failed to load EFI variables' if the file is missing

[Heinrich Schuchardt]

On 1/19/23 12:45, Ilias Apalodimas wrote:
> Hi Etienne,
>
> On Thu, 19 Jan 2023 at 13:17, Etienne Carriere
> <etienne.carriere at linaro.org> wrote:
>>
>> On Wed, 18 Jan 2023 at 17:12, Ilias Apalodimas
>> <ilias.apalodimas at linaro.org> wrote:
>>>
>>> When we try to load EFI variables from a file in the ESP partition and the
>>> file is missing We print a scary error looking like
>>> => printenv -e
>>> ** Unable to read file ubootefi.var **

This message is in line fs/fat/fat.c:1297:
printf("** Unable to read file %s **\n", filename);

The message is misplaced. If any message is written, it should be in
fat_read_at().

But I think fat_read_at() should also be quiet. It is the task of the
calling application to shout out if a file cannot be read.

I have not checked if a test in test/py/tests/test_fs/ relies on the
error message.

>>> Failed to load EFI variables

If there is a writable ESP, file ubootefi.var is created on first boot.
So this message should only once in the lifecycle of the board.

Afterwards this message indicates that something is really wrong.

If board vendors doesn't like it, they can create a dummy file.

Best regards

Heinrich

>>>
>>> This is not an error though since the file wasn't there to begin with.
>>> So silence the warning by aborting the load if the file is not there,
>>> instead of failing the load.
>>>
>>> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
>>> ---
>>>   lib/efi_loader/efi_var_file.c | 6 ++++++
>>>   1 file changed, 6 insertions(+)
>>>
>>> diff --git a/lib/efi_loader/efi_var_file.c b/lib/efi_loader/efi_var_file.c
>>> index 62e071bd8341..7d7141473634 100644
>>> --- a/lib/efi_loader/efi_var_file.c
>>> +++ b/lib/efi_loader/efi_var_file.c
>>> @@ -223,6 +223,12 @@ efi_status_t efi_var_from_file(void)
>>>                  return EFI_OUT_OF_RESOURCES;
>>>          }
>>>
>>> +       ret = efi_set_blk_dev_to_system_partition();
>>> +       if (ret != EFI_SUCCESS)
>>> +               goto error;
>>> +       if (!fs_exists(EFI_VAR_FILE_NAME))
>>> +               goto error;
>>> +
>>>          ret = efi_set_blk_dev_to_system_partition();
>>>          if (ret != EFI_SUCCESS)
>>>                  goto error;
>>
>> This later call to efi_set_blk_dev_to_system_partition() can be
>> removed since already done above.
>>
>
> iirc fs_exists() unconditionally calls fs_close() so we need that double call
>
> Cheers
> /Ilias
>> Etienne
>>
>>> --
>>> 2.38.1
>>>