Re: Analysis of clang results against the nmap-npingchanges branch for nping directory only.

[James Rogers <jamesmrogers () gmail com>]

On Wed, Jun 13, 2012 at 2:09 PM, David Fifield <david () bamsoftware com> wrote:
> On Wed, Jun 13, 2012 at 02:05:55PM -0400, James Rogers wrote:
> > Only found two real issues:
> >
> > API           Argument with 'nonnull' attribute passed null   nping
> > /common_modified.cc   490     20
> > 490   s = strchr(addy[i],',');
> >                  ^^^^
> >       20 Null pointer passed as an argument to a 'nonnull' parameter
> >
> >       Is a bug.  hostexp is never checked to make sure it is not NULL.
> >       371     char *hostexp = strdup(target_expr);
> >       386     addy[0] = addy[1] = addy[2] = addy[3] = addy[4] = NULL;
> >       387     addy[0] = r = hostexp;
> >
> >
> > Dead store    Dead assignment                                 nping /EchoServer.cc            1507    1
> > 1507  loopret=nsock_loop(nsp, 1000);
> >
> >       Value stored to 'loopret' is never read
> >
> >       This is a bug.  Easy to fix.
> >       There were a lot more references to loopret that have been removed in
> > this branch, this looks like the last one remaining.
> >
> > The rest of the bugs were generated by clang not recognizing that
> > nping_fatal() and fatal() do not return.
>
> Is there a way to annotate these functions so that Clang can know they
> don't return? In nmap_error.h we have for example,
>
> void fatal(const char *fmt, ...)
>     __attribute__ ((noreturn))
>
> But that's missing in nping/output.h. If you add it, do those spurious
> warnings go away?
>
> David Fifield

The documentation talked about ways to mark things in general, but I
didn't see any detailed explanation of how to do that.

I'll add that attribute to the nmap-npingchanges version I have and
see if it stops these bugs from being reported when I run the tool
again.

James Rogers
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