[libvirt] [PATCH 9/9] virstoragefile: Resolve Coverity DEADCODE

[Eric Blake]

On 09/11/2014 06:06 PM, John Ferlan wrote:
> Coverity complains that the condition "size + 1 == 0" cannot happen.
> Since 'size' is unsigned 32bit value set using virReadBufInt32BE.
> Thus rather than + 1, it seems the comparison should be is it at
> max now and if so, return the failure.
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
>  src/util/virstoragefile.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
> index 299edcd..0219ce8 100644
> --- a/src/util/virstoragefile.c
> +++ b/src/util/virstoragefile.c
> @@ -393,7 +393,7 @@ qcowXGetBackingStore(char **res,
>      }
>      if (offset + size > buf_size || offset + size < offset)
>          return BACKING_STORE_INVALID;
> -    if (size + 1 == 0)
> +    if (size == UINT_MAX)

Is this dead code?  After all, we just checked that offset+size is not
larger than buf_size (and buf_size is smaller than UINT_MAX); and also
that offset+size didn't overflow.

>          return BACKING_STORE_INVALID;
>      if (VIR_ALLOC_N(*res, size + 1) < 0)
>          return BACKING_STORE_ERROR;
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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