Re: [Qemu-devel] [PATCH V3] net/colo-compare.c: Fix memory leak and code style issue.

["Zhang, Chen" <chen.zhang@intel.com>]

> -----Original Message-----
> From: Philippe Mathieu-Daudé [mailto:philmd@redhat.com]
> Sent: Thursday, July 18, 2019 6:54 PM
> To: Peter Maydell <peter.maydell@linaro.org>
> Cc: Zhang, Chen <chen.zhang@intel.com>; Li Zhijian <lizhijian@cn.fujitsu.com>;
> Jason Wang <jasowang@redhat.com>; qemu-dev <qemu-devel@nongnu.org>;
> Zhang Chen <zhangckid@gmail.com>
> Subject: Re: [Qemu-devel] [PATCH V3] net/colo-compare.c: Fix memory leak
> and code style issue.
> 
> On 7/18/19 12:37 PM, Peter Maydell wrote:
> > On Thu, 18 Jul 2019 at 11:28, Philippe Mathieu-Daudé <philmd@redhat.com>
> wrote:
> >>
> >> On 7/18/19 11:22 AM, Zhang Chen wrote:
> >>> From: Zhang Chen <chen.zhang@intel.com>
> >>>
> >>> This patch to fix the origin "char *data" menory leak, code style
> >>> issue
> >>
> >> "memory"

Oh, I will fix this typo in next version.

> >>
> >>> and add necessary check here.
> >>> Reported-by: Coverity (CID 1402785)
> >>>
> >>> Signed-off-by: Zhang Chen <chen.zhang@intel.com>
> >>> ---
> >>>  net/colo-compare.c | 28 +++++++++++++++++++++-------
> >>>  1 file changed, 21 insertions(+), 7 deletions(-)
> >>>
> >>> diff --git a/net/colo-compare.c b/net/colo-compare.c index
> >>> 909dd6c6eb..fcccb4c6f6 100644
> >>> --- a/net/colo-compare.c
> >>> +++ b/net/colo-compare.c
> >>> @@ -127,6 +127,17 @@ static int compare_chr_send(CompareState *s,
> >>>                              uint32_t vnet_hdr_len,
> >>>                              bool notify_remote_frame);
> >>>
> >>> +static bool packet_matches_str(const char *str,
> >>> +                               uint8_t *buf,
> >>
> >> You can use 'uint8_t *buf'.
> >
> > ?? that seems to be the same as what is written...
> 
> Oops sorry, I copy/pasted and  did not noticed I removed the 'const'
> word. So I meant: You can use 'const uint8_t *buf'

OK.

Thanks
Zhang Chen

> 
> >>
> >>> +                               uint32_t packet_len) {
> >>> +    if (packet_len != strlen(str)) {
> >>> +        return false;
> >>> +    }
> >>> +
> >>> +    return !memcmp(str, buf, strlen(str));
> >>
> >> If you don't want to use a local variable to hold strlen(str), you
> >> can reuse packet_len since it is the same value:
> >>
> >>        return !memcmp(str, buf, packet_len);
> >>
> >> However it makes the review harder, so I'd prefer using a str_len local var.
> >
> > I'm pretty sure the compiler is going to optimise the
> > strlen() away into a compile time constant anyway, so this is somewhat
> > unnecessary micro-optimisation I think.
> 
> I was not sure, I'm glad to learn that :)
> 
> Thanks,
> 
> Phil.