Re: [Qemu-trivial] [Qemu-devel] [PATCH] sockets: avoid formatting buffer that may not be NULL terminated

[Markus Armbruster]

Stefan Hajnoczi <address@hidden> writes:

> On Mon, Jun 26, 2017 at 12:19:40PM +0200, Thomas Huth wrote:
>> On 26.06.2017 12:11, Daniel P. Berrange wrote:
>> > The 'sun_path' field in the sockaddr_un struct is not required
>> > to be NULL termianted, so when reporting an error, we must use
>> 
>> s/NULL/NUL/
>> 
>> NULL is a pointer, NUL is the '\0' character.
>
> I wanted to point out the same thing to someone recently, so I chased up
> a reference to the NUL character in RFC 20 "ASCII format for Network
> Interchange".  After all, no one can argue with an RFC.
>
> What I found shocked me!  There must be a typo in the ASCII RFC:
> https://tools.ietf.org/html/rfc20#section-5.2
>
> I closed my browser tab quickly and headed to Wikipedia instead.  If the
> primary source didn't support my argument, I could always count on good
> old Wikipedia...
>
> But do you know what I found?  Someone had conflated nul and null on the
> Wikipedia entry:
> https://en.wikipedia.org/wiki/Null_character
>
> Amateurs!  The Wikipedia editors probably didn't have the intellectual
> calibre to question the correctness of the RFC text the way I did.
>
> But to cut a long story short, as my search continued the evidence
> became overwhelming.  It is acceptable to refer to the nul character as
> the null character.
>
> Coming back to the patch in question, although we can't complain about
> the "NULL" it's with considerable joy that I'd like to highlight:
>
> s/termianted/terminated/
>
> :)
> Stefan

Despite this shocking, shocking precedence, I formally object to the use
of NULL in the context of C for anything other than "one particular null
pointer".  C's confusing enough without overloading identifiers.