Re: bin/50909: src/sbin/ifconfig/env.c: 2 * clumsy call to memset ?

[David Young <dyoung%pobox.com@localhost>]

On Mon, Mar 07, 2016 at 12:20:00PM +0000, dcb314%hotmail.com@localhost wrote:
> >Number:         50909
> >Category:       bin
> >Synopsis:       src/sbin/ifconfig/env.c: 2 * clumsy call to memset ?
> 
> [src/sbin/ifconfig/env.c:145]: (performance) Buffer 'buf' is being written before its old content has been used.
> 
> Source code is
> 
>     memset(buf, 0, buflen);
>     memcpy(buf, prop_data_data_nocopy(data), datalen);
> 
> Maybe better code
>    
>    memcpy(buf, prop_data_data_nocopy(data), datalen);
>    memset(buf + datalen, 0, buflen - datalen);

Hold on a minute.  The previous code was simpler and more obviously
harmless.  Is this change *really* justified on performance grounds? :-)

Dave

-- 
David Young
dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981