linux-kernel - Re: [PATCH] vsprintf: replace space with readable '=' before crng is ready

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Message-ID: <20180213194618.GA2999@eros>
Date:   Wed, 14 Feb 2018 06:46:18 +1100
From:   "Tobin C. Harding" <me@...in.cc>
To:     Rasmus Villemoes <linux@...musvillemoes.dk>
Cc:     Shunyong Yang <shunyong.yang@...-semitech.com>,
        linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Joey Zheng <yu.zheng@...-semitech.com>
Subject: Re: [PATCH] vsprintf: replace space with readable '=' before crng is
 ready

On Tue, Feb 13, 2018 at 08:16:57AM +0100, Rasmus Villemoes wrote:
> On 13 February 2018 at 07:20, Shunyong Yang
> <shunyong.yang@...-semitech.com> wrote:
> 
> >
> > This patch replaces space with readable "=" when output needs padding.
> > Following is the output after applying the patch,
> 
> > Suggested-by: Rasmus Villemoes <linux@...musvillemoes.dk>
> >
> >         if (unlikely(!have_filled_random_ptr_key)) {
> > +               char *ptrval_str = "(ptrval)";
> > +               char str[default_width + 1];
> > +               int len = strlen(ptrval_str);
> > +
> > +               if (default_width > len) {
> > +                       int pos;
> > +
> > +                       pos = (default_width - len) / 2;
> > +                       memset(str, '=', default_width);
> > +                       memcpy(str + pos + 1, ptrval_str + 1, len - 2);
> > +                       str[0] = '(';
> > +                       str[default_width - 1] = ')';
> > +                       str[default_width] = 0;
> > +                       ptrval_str = str;
> > +               }
> > +
> 
> I'm sorry, but that's way too convoluted.
> 
> >                 spec.field_width = default_width;
> >                 /* string length must be less than default_width */
> > -               return string(buf, end, "(ptrval)", spec);
> > +               return string(buf, end, ptrval_str, spec);
> >         }
> 
> I was thinking of just doing something like
> 
> -               return string(buf, end, "(ptrval)", spec);
> +               return string(buf, end, sizeof(void *) == 8 ?
> "(====ptrval====)" : "(ptrval)", spec);

Awesome.