[libvirt] [PATCH 1/7] Coverity: Fix the forward_null error in Python binding codes

[Daniel P. Berrange]

On Wed, May 02, 2012 at 10:51:32PM +0800, Osier Yang wrote:
> Related coverity log:
> 
> Error: FORWARD_NULL:
> /builddir/build/BUILD/libvirt-0.9.10/python/libvirt-override.c:355:
> assign_zero: Assigning: "params" = 0.
> /builddir/build/BUILD/libvirt-0.9.10/python/libvirt-override.c:458:
> var_deref_model: Passing null variable "params" to function
> "getPyVirTypedParameter", which dereferences it. (The dereference is assumed on
> the basis of the 'nonnull' parameter attribute.)
> ---
>  python/libvirt-override.c |   10 +++++-----
>  1 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/python/libvirt-override.c b/python/libvirt-override.c
> index 56f96ba..7fd7cb7 100644
> --- a/python/libvirt-override.c
> +++ b/python/libvirt-override.c
> @@ -435,14 +435,14 @@ libvirt_virDomainGetCPUStats(PyObject *self ATTRIBUTE_UNUSED, PyObject *args)
>              goto error;
>          }
>  
> +        if (VIR_ALLOC_N(params, nparams) < 0) {
> +            error = PyErr_NoMemory();
> +            goto error;
> +        }
> +
>          if (nparams) {
>              sumparams = nparams;
>  
> -            if (VIR_ALLOC_N(params, nparams) < 0) {
> -                error = PyErr_NoMemory();
> -                goto error;
> -            }
> -
>              LIBVIRT_BEGIN_ALLOW_THREADS;
>              i_retval = virDomainGetCPUStats(domain, params, nparams, -1, 1, flags);
>              LIBVIRT_END_ALLOW_THREADS;

NACK, the correct fix is to remove teh NONNULL annotation from
getPyVirTypedParameter() since it is perfectly acceptable to
pass in NULL there & the code handles it fine.

Daniel
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