On Thu, 22 Dec 2016, Thomas Adam wrote:
> On Tue, Dec 20, 2016 at 08:45:26PM +0100, SF Markus Elfring wrote:
> > * A filter criterium like “T = strdup(...);” was specified.
> > How do you think about to use a SmPL disjunction (or an advanced SmPL
> > constraint
> > on a metavariable with the type “identifier” instead)?
> >
> > * Can the function call “pkg_emit_errno” become a bit more generic by
> > passing
> > a string from previously matched data?
> >
> > * Would you like to check any more cases so that the technology “data flow
> > analysis”
> > will be also needed here?
>
> You're right. The next step I'm looking at is making my checks automatable so
> that they can truly patch code properly. Right now, what I have is merely a
> "best guess" placeholder which is inserted, leaving the programmer having to
> go in and correct the compilation.
>
> Consider the following rule:
>
> T = strdup(...);
> + if (T == NULL) {
> + pkg_errno("strdup", __func__);
> + return (EPKG_FATAL);
> + }
> ... when != (T == NULL)
> when != (T != NULL)
> ? T = strdup(...);
>
> The problem is that if this rule matches, the inserted code will always be:
>
> pkg_errno("stdup", __func__);
> return (EPKG_FATAL);
>
> That return should *not* be there if the return type of the function the code
> is
> being inserted to is anything other than "int". Likewise, if the function
> returns void, it should be "return;", or a pointer should be "NULL".
>
> Is there a clever way of conditionally making this change?
Doing something based on the type would be possible. For example, you can
have a pattern like (simplified version):
void f(...) { <...
x = foo();
+ if (!foo) return;
...> }
Choosing real error handling code that would free the previously allocated
resources is probably beyond the abilities of Coccinelle.
julia_______________________________________________
Cocci mailing list
[email protected]
https://systeme.lip6.fr/mailman/listinfo/cocci
