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Re: [libvirt] [PATCH v2] Avoid integer wrap on remotePortMax in QEMU driver



On 01/17/2013 06:00 AM, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange redhat com>
> 
> The QEMU driver default max port is 65535, but it then increments
> this by 1 to 65536. This maps to 0 in an unsigned short :-( This
> was apparently done so that for() loops could use "< max" instead
> of "<= max". Remove this insanity and just make the loop do the
> right thing.
> ---
>  src/qemu/qemu_conf.c         | 4 ----
>  src/util/virportallocator.c  | 6 +++---
>  tests/virportallocatortest.c | 2 +-
>  3 files changed, 4 insertions(+), 8 deletions(-)
> 

> @@ -103,7 +103,7 @@ int virPortAllocatorAcquire(virPortAllocatorPtr pa,
>      *port = 0;
>      virObjectLock(pa);
>  
> -    for (i = pa->start ; i < pa->end && !*port; i++) {
> +    for (i = pa->start ; i <= pa->end && !*port; i++) {
>          int reuse = 1;

This loop is still broken, unless you change the type of 'i' to be wider
than unsigned short.

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

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