On Mon, 11 May 2015, Nicholas Mc Guire wrote:
> On Sun, 10 May 2015, Dan Carpenter wrote:
>
> > I don't really have a strong opinion either way... It's unlikely that
> > we will introduce a bug here and if we did, I think it would be caught
> > immediately in testing.
> >
> > It's pretty common to treat the first member of a struct as special.
> > What annoys me is when people do
> >
> > struct foo {
> > int one, two, three;
> > whatever;
> > };
> >
> > memcpy(&foo.one, src, sizoef(struct foo));
> >
> > Argh!? These triger buffer overflows warnings in Smatch and I don't
> > see the point since &foo.one is less readable than &foo! Oh well, I
> > think these were common enough, I had to treat it as idiomatic and add a
> > special case for them.
> >
> just ran a naive scanner for that pattern but only could find this one instance
>
> ./net/sctp/sm_make_chunk.c:3103 ugly memset
> 3102 if (af->is_any(&addr))
> 3103 memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
>
> my scanner ist:
>
> @uses_first@
> identifier f;
> idexpression s;
Maybe generalize s (ie expression) and the size (ie, don't specify
anything)? The sizeof could be a type also.
julia
> identifier e;
> position p;
> @@
>
> f(...){
> <+...
> * memcpy@p(&s.e,...,sizeof(s));
> ...+>
> }
>
> @script:python@
> p << uses_first.p;
> @@
> print "%s:%s ugly memset" % (p[0].file,p[0].line)
>
> so is my scanner broken/incomplete or has this pattern lost its popularity ?
>
> thx!
> hofrat
>
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