From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752630Ab2GZApQ (ORCPT ); Wed, 25 Jul 2012 20:45:16 -0400 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:49218 "EHLO LGEMRELSE6Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735Ab2GZApP convert rfc822-to-8bit (ORCPT ); Wed, 25 Jul 2012 20:45:15 -0400 X-AuditID: 9c930179-b7bdcae000003d91-15-501093185657 From: Namhyung Kim To: Arnaldo Carvalho de Melo Cc: Ingo Molnar , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Paul Mackerras , Peter Zijlstra , Ulrich Drepper , Arnaldo Carvalho de Melo Subject: Re: [PATCH 15/19] perf tools: use XSI-complaint version of strerror_r() instead of GNU-specific References: <1343238094-12481-1-git-send-email-acme@infradead.org> <1343238094-12481-16-git-send-email-acme@infradead.org> Date: Thu, 26 Jul 2012 09:39:59 +0900 In-Reply-To: <1343238094-12481-16-git-send-email-acme@infradead.org> (Arnaldo Carvalho de Melo's message of "Wed, 25 Jul 2012 14:41:30 -0300") Message-ID: <87lii75p9c.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.97 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 25 Jul 2012 14:41:30 -0300, Arnaldo Carvalho de Melo wrote: > From: Kirill A. Shutemov > > Perf uses GNU-specific version of strerror_r(). The GNU-specific strerror_r() > returns a pointer to a string containing the error message. This may be either > a pointer to a string that the function stores in buf, or a pointer to some > (immutable) static string (in which case buf is unused). > > In glibc-2.16 GNU version was marked with attribute warn_unused_result. It > triggers few warnings in perf: > > util/target.c: In function ‘perf_target__strerror’: > util/target.c:114:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result] > ui/browsers/hists.c: In function ‘hist_browser__dump’: > ui/browsers/hists.c:981:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result] > > They are bugs. > > Let's fix strerror_r() usage. > > Signed-off-by: Kirill A. Shutemov > Acked-by: Ulrich Drepper > Cc: Ingo Molnar > Cc: Paul Mackerras > Cc: Peter Zijlstra > Cc: Ulrich Drepper > Link: http://lkml.kernel.org/r/20120723210654.GA25248@shutemov.name > [ committer note: s/assert/BUG_ON/g ] > Signed-off-by: Arnaldo Carvalho de Melo > --- > tools/perf/ui/browsers/hists.c | 4 ++-- > tools/perf/util/target.c | 11 ++++++++++- > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c > index 482f051..413bd62 100644 > --- a/tools/perf/ui/browsers/hists.c > +++ b/tools/perf/ui/browsers/hists.c > @@ -978,8 +978,8 @@ static int hist_browser__dump(struct hist_browser *browser) > fp = fopen(filename, "w"); > if (fp == NULL) { > char bf[64]; > - strerror_r(errno, bf, sizeof(bf)); > - ui_helpline__fpush("Couldn't write to %s: %s", filename, bf); > + const char *err = strerror_r(errno, bf, sizeof(bf)); > + ui_helpline__fpush("Couldn't write to %s: %s", filename, err); > return -1; > } > > diff --git a/tools/perf/util/target.c b/tools/perf/util/target.c > index 1064d5b..3f59c49 100644 > --- a/tools/perf/util/target.c > +++ b/tools/perf/util/target.c > @@ -110,8 +110,17 @@ int perf_target__strerror(struct perf_target *target, int errnum, > int idx; > const char *msg; > > + BUG_ON(buflen > 0); > + No! It should be BUG_ON(buflen == 0); Thanks, Namhyung > if (errnum >= 0) { > - strerror_r(errnum, buf, buflen); > + const char *err = strerror_r(errnum, buf, buflen); > + > + if (err != buf) { > + size_t len = strlen(err); > + char *c = mempcpy(buf, err, min(buflen - 1, len)); > + *c = '\0'; > + } > + > return 0; > }