From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.formilux.org (mta1.formilux.org [51.159.59.229]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7851130CDAB for ; Sun, 22 Mar 2026 08:43:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=51.159.59.229 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774169034; cv=none; b=LCt88oTouE+/zVGiJipu8m1G4C+Dk7hUffUY+xoLKboCdlMjBdC4S7+7YZJ4Ydqitbm9dYX3tvhZpgKKWJ+cdubJTBq7McSKW0bObuhSw/0YY/sRgOk2Znk3xX3wkP5Pi+uD3IECDZybiCT3+cnF3STtyXV/5fJRJGVBxge7v18= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774169034; c=relaxed/simple; bh=UDtqkcQloH0rDK7cyqLMAcXseggA0Tvjwj2AoZASyM4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E5iSDvxLMMvkwkPbuHlELa83+cDb9tI7LH/Zp9nPX/3gVjCcXgVur3o/a+HOZbZuxBw1pVL0IxD+rMLPyZ0yNLqzPpJXPTMs5NJ8JlRnrjWPnZFWUIEmwpMpHQRmHerfQTWEJidAQkJ4j8JRpCrAsU7kDNfIfe8h3tJTj9KrALY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=1wt.eu; spf=pass smtp.mailfrom=1wt.eu; dkim=pass (1024-bit key) header.d=1wt.eu header.i=@1wt.eu header.b=vJyrhOqq; arc=none smtp.client-ip=51.159.59.229 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=1wt.eu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=1wt.eu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=1wt.eu header.i=@1wt.eu header.b="vJyrhOqq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1wt.eu; s=mail; t=1774169030; bh=KHpXrO0XcjOlnxtT18NlIBTjIG9VhyPyOX7bAUWKvjc=; h=From:Message-ID:From; b=vJyrhOqqF0b3uXFD4+d4z0Cbjj2tv5sA+e4EwEZ3qzQUeR23rDmbQf1uEkNwRKGqA inyrLJOyVhoBcHirxKCcHbWr2PRlHufA6/0EjjVgl9VD/Wrl2/om7KK9S5+Ddh2TCj w+SypcL8lxAbeODXs0nW6Njl3YJe/EftnUqPAdXc= Received: from 1wt.eu (ded1.1wt.eu [163.172.96.212]) by mta1.formilux.org (Postfix) with ESMTP id 96697C0A63; Sun, 22 Mar 2026 09:43:50 +0100 (CET) Date: Sun, 22 Mar 2026 09:43:50 +0100 From: Willy Tarreau To: David Laight Cc: Thomas =?iso-8859-1?Q?Wei=DFschuh?= , Daniel Palmer , linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/nolibc: fix libc-test with musl libc Message-ID: References: <20260318-nolibc-tests-musl-v1-1-884cd7f48646@weissschuh.net> <20260318225231.00b2f462@pumpkin> <20260319105207.07b66eea@pumpkin> <021586fd-ef90-4b8f-9d04-8055d457ff89@t-8ch.de> <20260319224436.554d2ad4@pumpkin> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260319224436.554d2ad4@pumpkin> On Thu, Mar 19, 2026 at 10:44:36PM +0000, David Laight wrote: > On Thu, 19 Mar 2026 17:18:33 +0100 > Thomas Weißschuh wrote: > > > On 2026-03-19 10:52:07+0000, David Laight wrote: > > > On Wed, 18 Mar 2026 22:52:31 +0000 > > > David Laight wrote: > > > > > > > On Wed, 18 Mar 2026 18:20:46 +0100 > > > > Thomas Weißschuh wrote: > > > > > > > > > Some of the nolibc testcases fail on musl. In these cases nolibc mirrors > > > > > the non-standard behavior of glibc. > > > > > > > > > > Avoid the failures by only running these testcases on nolibc itself. > > > > > > > > > > Fixes: a5f00be9b3b0 ("tools/nolibc: Add a simple test for writing to a FILE and reading it back") > > > > > Fixes: d94393e48c09 ("tools/nolibc/printf: Add support for length modifiers tzqL and formats iX") > > > > > Fixes: c2d234d3dc56 ("tools/nolibc/printf: Special case 0 and add support for %#x") > > > > > Fixes: 63befd993da4 ("tools/nolibc/printf: Add support for zero padding and field precision") > > > > > Fixes: d94393e48c09 ("tools/nolibc/printf: Add support for length modifiers tzqL and formats iX") > > > > > Signed-off-by: Thomas Weißschuh > > > > > --- > > > > > I am thinking about folding the printf fixups directly into the original > > > > > patches. Any objections? > > > > > --- > > > > > tools/testing/selftests/nolibc/nolibc-test.c | 12 ++++++------ > > > > > 1 file changed, 6 insertions(+), 6 deletions(-) > > > > > > > > > > diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c > > > > > index 180611aabbfb..b03fb9aeb54e 100644 > > > > > --- a/tools/testing/selftests/nolibc/nolibc-test.c > > > > > +++ b/tools/testing/selftests/nolibc/nolibc-test.c > > > > > @@ -867,7 +867,7 @@ int test_file_stream(void) > > > > > > > > > > errno = 0; > > > > > r = fwrite("foo", 1, 3, f); > > > > > - if (r != 0 || errno != EBADF) { > > > > > + if (r != 0 || (is_nolibc && errno != EBADF)) { > > > > > fclose(f); > > > > > return -1; > > > > > } > > > > > @@ -1824,13 +1824,13 @@ static int run_printf(int min, int max) > > > > > CASE_TEST(hex_alt_prec); EXPECT_VFPRINTF(1, "| 0x02|0x03| 0x123|", "|%#5.2x|%#04x|%#6.2x|", 2, 3, 0x123); break; > > > > > CASE_TEST(hex_0_alt); EXPECT_VFPRINTF(1, "|0|0000| 00|", "|%#x|%#04x|%#5.2x|", 0, 0, 0); break; > > > > > CASE_TEST(pointer); EXPECT_VFPRINTF(1, "0x1", "%p", (void *) 0x1); break; > > > > > - CASE_TEST(pointer_NULL); EXPECT_VFPRINTF(1, "|(nil)|(nil)|", "|%p|%.4p|", (void *)0, (void *)0); break; > > > > > - CASE_TEST(string_NULL); EXPECT_VFPRINTF(1, "|(null)||(null)|", "|%s|%.5s|%.6s|", (void *)0, (void *)0, (void *)0); break; > > > > > + CASE_TEST(pointer_NULL); EXPECT_VFPRINTF(is_nolibc, "|(nil)|(nil)|", "|%p|%.4p|", (void *)0, (void *)0); break; > > > > > + CASE_TEST(string_NULL); EXPECT_VFPRINTF(is_nolibc, "|(null)||(null)|", "|%s|%.5s|%.6s|", (void *)0, (void *)0, (void *)0); break; > > > > > CASE_TEST(percent); EXPECT_VFPRINTF(1, "a%d42%69%", "a%%d%d%%%d%%", 42, 69); break; > > > > > - CASE_TEST(perc_qual); EXPECT_VFPRINTF(1, "a%d2", "a%-14l%d%d", 2); break; > > > > > - CASE_TEST(invalid); EXPECT_VFPRINTF(1, "a%12yx3%y42%P", "a%12yx%d%y%d%P", 3, 42); break; > > > > > + CASE_TEST(perc_qual); EXPECT_VFPRINTF(is_nolibc, "a%d2", "a%-14l%d%d", 2); break; > > > > > + CASE_TEST(invalid); EXPECT_VFPRINTF(is_nolibc, "a%12yx3%y42%P", "a%12yx%d%y%d%P", 3, 42); break; > > > > > CASE_TEST(intmax_max); EXPECT_VFPRINTF(1, "9223372036854775807", "%lld", ~0ULL >> 1); break; > > > > > - CASE_TEST(intmax_min); EXPECT_VFPRINTF(1, "-9223372036854775808", "%Li", (~0ULL >> 1) + 1); break; > > > > > + CASE_TEST(intmax_min); EXPECT_VFPRINTF(is_nolibc, "-9223372036854775808", "%Li", (~0ULL >> 1) + 1); break; > > > > > CASE_TEST(uintmax_max); EXPECT_VFPRINTF(1, "18446744073709551615", "%ju", ~0ULL); break; > > > > > CASE_TEST(truncation); EXPECT_VFPRINTF(1, "012345678901234567890123456789", "%s", "012345678901234567890123456789"); break; > > > > > CASE_TEST(string_width); EXPECT_VFPRINTF(1, " 1", "%10s", "1"); break; > > > > > > > > Hmmm.... > > > > Those are deliberately matching glibc behaviour, at least annotating that > > > > might be useful. > > > > Can you think of a way of detecting whether glibc is being used? > > > > Even !is_musl might be better than is_nolibc - even even they are the same. > > > > > > Thinking more, the nil/null tests want is_nolibc || is_glibc. > > > Setting is_glibc might be hard (unless done from the command line). > > > > We already have a test for __GLIBC__. We can also use that for > > is_glibc. > > > > > The musl people think you don't need to know because their library is conformant. > > > I found something from someone trying to detect pthread_setname_np(), > > > glibc's features.h will set __USE_GNU (and similar) that musl doesn't set. > > > There might also be issues with bionic and uClibc. > > > > Why would __GLIBC__ not work? > > It wasn't mentioned in the stack overflow article I found :-( I confirm, I'm using it all the time as well, the macro contains the lib's major version (2). David you can check for such macros this way if you're interested: $ printf "#include \n" | gcc -dM -E -xc -|grep GLIBC Willy