From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753940AbcBVKNB (ORCPT ); Mon, 22 Feb 2016 05:13:01 -0500 Received: from mga03.intel.com ([134.134.136.65]:47159 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781AbcBVKNA (ORCPT ); Mon, 22 Feb 2016 05:13:00 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,483,1449561600"; d="scan'208";a="657050159" Message-ID: <1456136021.13244.21.camel@linux.intel.com> Subject: Re: [PATCH 1/1] sscanf: implement basic character sets From: Andy Shevchenko To: Jessica Yu , Andrew Morton Cc: Rasmus Villemoes , Kees Cook , linux-kernel@vger.kernel.org Date: Mon, 22 Feb 2016 12:13:41 +0200 In-Reply-To: <1455931322-27170-1-git-send-email-jeyu@redhat.com> References: <1455931322-27170-1-git-send-email-jeyu@redhat.com> Organization: Intel Finland Oy Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.3-1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2016-02-19 at 20:22 -0500, Jessica Yu wrote: > Implement basic character sets for the '%[]' conversion specifier. > > The '%[]' conversion specifier matches a nonempty sequence of > characters > from the specified set of accepted (or with '^', rejected) characters > between the brackets. The substring matched is to be made up of > characters > in (or not in) the set. This implementation differs from its glibc > counterpart in that it does not support character ranges (e.g., 'a-z' > or > '0-9'), the hyphen '-' is *not* a special character, and the brackets > themselves cannot be matched. > > Signed-off-by: Jessica Yu > --- >  lib/vsprintf.c | 35 +++++++++++++++++++++++++++++++++++ >  1 file changed, 35 insertions(+) > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 525c8e1..6ee3e7f 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -2714,6 +2714,41 @@ int vsscanf(const char *buf, const char *fmt, > va_list args) >   num++; >   } >   continue; > + case '[': > + { > + char *s = (char *)va_arg(args, char *); > + char set[U8_MAX] = { 0 }; Hmm... 255 on stack, not the best idea. > + size_t (*op)(const char *str, const char > *set); > + size_t len = 0; > + bool negate = (*(fmt) == '^'); > + > + if (field_width == -1) > + field_width = SHRT_MAX; > + > + op = negate ? &strcspn : &strspn; > + if (negate) > + fmt++; > + > + len = strcspn(fmt, "]"); > + /* invalid format; stop here */ > + if (!len) > + return num; > + > + strncpy(set, fmt, len); Perhaps here you may allocate memory on heap and copy the given set. IIRC kstrndup() does this. > + /* advance fmt past ']' */ > + fmt += len + 1; > + > + len = (*op)(str, set); > + /* no matches */ > + if (!len) > + return num; > + > + while (*str && len-- && field_width--) > + *s++ = *str++; > + *s = '\0'; > + num++; > + } > + continue; >   case 'o': >   base = 8; >   break; -- Andy Shevchenko Intel Finland Oy