On 06.07.2016 15:47, Marc Hartmayer wrote:
> The virDomainGetCPUStats() API contract permits nparams ==
> 0. print_cpu_usage() assumes nparams > 0 because the domtop example
> application isn't very useful if there are no statistics. Explicitly
> error out to avoid potentially using the local variable pos
> uninitialized.
>
> Reviewed-by: Boris Fiuczynski <fiuczy@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Sascha Silbe <silbe@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Bjoern Walk <bwalk@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxxxxxxx>
> ---
> examples/domtop/domtop.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/examples/domtop/domtop.c b/examples/domtop/domtop.c
> index 2283994..f8e250b 100644
> --- a/examples/domtop/domtop.c
> +++ b/examples/domtop/domtop.c
> @@ -203,6 +203,11 @@ print_cpu_usage(const char *dom_name,
> size_t nparams = now_nparams;
> bool delim = false;
>
> + if (nparams == 0) {
> + ERROR("parameter count is zero");
> + return;
> + }
> +
> if (then_nparams != now_nparams) {
> /* this should not happen (TM) */
> ERROR("parameters counts don't match");
>
Not that I dislike this patch, but I fail to see how can @pos be used
uninitialized if @nparams == 0. I mean, if @nparams == 0 and control
gets to line 221 where @j is set to 0. Since the condition is false, the
loop body is never executed leaving @pos unset. But, right after the
loop, there's check 'if (j == nparams)', which appears like true to me,
so and error is printed out and control jumps out from the function.
Or am I missing something?
Michal
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list