linux-kernel - Re: [PATCH v2 04/10] lib/vsprintf: add %*pE[achnops] format specifier

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Message-ID: <1404807878.5102.85.camel@smile.fi.intel.com>
Date:	Tue, 08 Jul 2014 11:24:38 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Joe Perches <joe@...ches.com>
Cc:	"John W . Linville" <linville@...driver.com>,
	Johannes Berg <johannes@...solutions.net>,
	devel@...verdev.osuosl.org, linux-wireless@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2 04/10] lib/vsprintf: add %*pE[achnops] format
 specifier

On Mon, 2014-07-07 at 09:50 -0700, Joe Perches wrote:
> On Mon, 2014-07-07 at 18:21 +0300, Andy Shevchenko wrote:
> 
> > diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> []
> >  static noinline_for_stack
> > +char *escaped_string(char *buf, char *end, u8 *addr, struct printf_spec spec,
> > +		     const char *fmt)
> []
> > +	if (spec.field_width == 0)
> > +		/* nothing to print */
> > +		return buf;
> []
> > +	len = spec.field_width < 0 ? 1 : spec.field_width;
> 
> If field_width is not specified, emit a single byte?

A single byte to be escaped (it might be \000, for example, on output).

> Perhaps better if -1 was accepted by string_escape_mem
> as a strlen request or just ignored as a 0 length is
> above.

Would it be any benefit here?

> fyi: hex_string emits nothing on printk("%ph", buf);

Works just fine. How did you check it?

pr_info("%ph\n", in); => test_string_helpers: 1b

(I suppose "\n" flushes a buffer for me.)

-- 
Andy Shevchenko <andriy.shevchenko@...el.com>
Intel Finland Oy

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