On Fri, Dec 16, 2016 at 08:21:35PM +0100, Julia Lawall wrote:
> The problem for the vset function is that a pattern like
>
> A
> ...
>
> requires that there be no A along all paths leaving from the matched A.
> Your code matching the first pattern is in a loop, so obviously there is
> at least one path that reaches A again. So the rule doesn't match. If
> you want to consider the region until A optionally occurs again, then you
> can write:
>
> A
> ...
> ?A
>
> The ? makes it optional.
Ah. I think I understand that, Julia. If I blindly modify the strdup rule to
this:
T = strdup(...);
+ if (T == NULL)
+ pkg_emit_errno("strdup", __func__);
?... when != (T == NULL)
? when != (T != NULL)
And then run:
spatch --in-place --sp-file ~/unchecked_malloc.cocci libpkg/pkg.c
This now captures the other remaining strdup() calls which were going
undetected. However, as a side-effect of this, the matching rule is adding in
the same NULL checks for function calls which already has them; hence a
doubling-up.
I appreciate I've just blindly followed your advice; could you perhaps
elaborate (and educate me) as to the correct way to ammend this rule?
Thanks.
Thomas
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