Re: [PATCH v6 0/2] Enable capsule loader interface for efi firmware updating

[Andy Lutomirski <luto@amacapital.net>]

On Mon, Oct 5, 2015 at 8:33 AM, Kweh, Hock Leong
<hock.leong.kweh@intel.com> wrote:
>> -----Original Message-----
>> From: Borislav Petkov [mailto:bp@alien8.de]
>> Sent: Saturday, October 03, 2015 5:06 PM
>> On Sat, Oct 03, 2015 at 03:18:41AM +0000, Kweh, Hock Leong wrote:
>> > > What does the error case look like? A standard glibc message about
>> > > write(2) failing?
>> > >
>> >
>> > Any upload fail error like -ENOMEM, -EINVAL, -EIO as well as error
>> > returned by efi_capsule_update() API.
>>
>> All I'm asking is, how does the user know that the upload didn't succeed?
>>
>
> I think it should depend on user app about which API they are using.
> If they are using syscall then errors would be returned through write(2).
> If they are using libc APIs fwrite, fputs and fprintf, then the errors would
> return through those APIs. However, this design is targeting the simple
> upload action "cat capsule.bin > /dev/efi_capsule_loader", so the errors
> should be returned through cat() or I/O redirection mechanism from
> shell terminal. Am I answered your question?
>
> Btw, I have an out topic question: I do notice you guys wrote in the message
> that a function look like write(2) or close(2). What actually the "2" mean there?

It's the manpage section.  Typing 'man 2 write' will give you the
manpage 'WRITE(2)'.  Section 2 is syscalls.

--Andy