[libvirt] [PATCHv3 3/4] Simplify linuxNodeGetCPUStats

Eric Blake eblake at redhat.com
Mon Jan 27 16:16:21 UTC 2014


On 01/22/2014 06:37 AM, Ján Tomko wrote:
> Split out the repetitive code.
> ---
>  src/nodeinfo.c | 77 +++++++++++++++++++++++-----------------------------------
>  1 file changed, 30 insertions(+), 47 deletions(-)
> 

ACK.


> @@ -722,51 +734,22 @@ linuxNodeGetCPUStats(FILE *procstat,
>                  continue;
>              }
>  
> -            for (i = 0; i < *nparams; i++) {
> -                virNodeCPUStatsPtr param = &params[i];

The old loop terminates early if *nparams < 4.

> +            if (virNodeCPUStatsAssign(&params[0], VIR_NODE_CPU_STATS_KERNEL,
> +                                      (sys + irq + softirq) * TICK_TO_NSEC) < 0)
> +                goto cleanup;
> +
> +            if (virNodeCPUStatsAssign(&params[1], VIR_NODE_CPU_STATS_USER,
> +                                      (usr + ni) * TICK_TO_NSEC) < 0)
> +                goto cleanup;
> +
> +            if (virNodeCPUStatsAssign(&params[2], VIR_NODE_CPU_STATS_IDLE,
> +                                      idle * TICK_TO_NSEC) < 0)
> +                goto cleanup;
> +
> +            if (virNodeCPUStatsAssign(&params[3], VIR_NODE_CPU_STATS_IOWAIT,
> +                                      iowait * TICK_TO_NSEC) < 0)
> +                goto cleanup;

whereas the new code blindly dereferences past the end of the array.
Needs another spin that avoids that issue.

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

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