Re: [PATCH 2/2] util: Consolidate and improve workarounds for clang-tidy issue 58992

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Sep 18, 2023 at 10:16:08AM +0200, Stefano Brivio wrote:
> On Fri, 15 Sep 2023 16:43:37 +1000
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > We have several workarounds for a clang-tidy bug where the checker doesn't
> > recognize that a number of system calls write to - and therefore initialise
> > - a socket address.  We can't neatly use a suppression, because the bogus
> > warning shows up some time after the actual system call, when we access
> > a field of the socket address which clang-tidy erroneously thinks is
> > uninitialised.
> > 
> > Consolidate these workarounds into one place by using macros to implement
> > wrappers around affected system calls which add a memset() of the sockaddr
> > to silence clang-tidy.  This removes the need for the individual memset()
> > workarounds at the callers - and the somewhat longwinded explanatory
> > comments.
> > 
> > We can then use a #define to not include the hack in "real" builds, but
> > only consider it for clang-tidy.
> 
> I'm probably missing something, but wouldn't it be more obvious to
> conditionally define the wrapper itself? That is,
> 
> #ifdef CLANG_TIDY_58992
> # define recvfrom(s, buf, len, flags, src, addrlen)		\
> 	wrap_recvfrom((s), (buf), (len), (flags), (src), (addrlen))
> #endif
> 
> instead of doing that in sa_init()?

Eh.. maybe?  I was going for minimal differences in the preprocessed
code between the two cases, to reduce the chances of missing some
unrelated real problem due to the fact we're kind of lying to our
static checker.

I don't feel that strongly about it though, so whichever you'd prefer
is fine.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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