From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailtransmit04.runbox.com (mailtransmit04.runbox.com [185.226.149.37]) (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 C239439B964 for ; Mon, 2 Mar 2026 10:18:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.37 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772446743; cv=none; b=OT0Ft0JlexfLrl8ygC0e7GibcGlJjs1vhqLARTxt/rk4qJuELNn+SRdUOp5zvdS8P5FzuEvv4P3zTQTQc8MBR7IDK6BDjpwXOC85HswylFdP6h4YVMgug8921+5qlto8uoIv7iEf462PW/PoD2N/MqK36vd+dod+PYW4kOffbuM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772446743; c=relaxed/simple; bh=GTP3oRZVXjBN+khWC+cEI8DoN0ewVC9GlCDUeil1B/M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=CN2jP8LGiJVk2vNcZPeuLAEJD7pMlbXzYVbq5+OcwlJDRuXY829DM4j8cngiN/W2GygXklXaPtA4ZIvh4ZUJaM+L3clzbKkB2EbjC2zDSSHXiy81uPhz5ZOSpqIvAafB1Z6JdvOk+rcLhOLYT20Z+ChiqD5CTo5arDuokODWYR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=runbox.com; dkim=pass (2048-bit key) header.d=runbox.com header.i=@runbox.com header.b=QUKd00yf; arc=none smtp.client-ip=185.226.149.37 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=runbox.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=runbox.com header.i=@runbox.com header.b="QUKd00yf" Received: from mailtransmit02.runbox ([10.9.9.162] helo=aibo.runbox.com) by mailtransmit04.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1vx0MZ-00385a-4C; Mon, 02 Mar 2026 11:18:55 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=runbox.com; s=selector2; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To :Message-Id:Date:Subject:Cc:To:From; bh=88M3sbDF/zPomo+REuKBu8a/s7isuTXZs+VJlaLgUfQ=; b=QUKd00yf69Ncnacv/1+mZuIxSI TQgWzIIT9Hrn/34V1d2yk4+aTiXlOL3M48MpF/kQnvdE22b0Mk/OqtkvIFEwGK1bgb7ZUJFJiEP7/ klJPfVwPGC8/yec4XDjxf7WyMGeCU8rM65Rh3kxTlI2FL9WztKiTEFkAvscDPjurQfRRbj4Wep0Q7 uu5z6+qZH8YC3WrTr/+f1IzD4+iTc2w+v4x4pRLSZoNKtoHFprx7jyrS7AwMGANsybVan0H5uuGdu XPMvVWJquo55gcXbhVCiIr5dVGXfEii06OEbVSezeVKaYl0GlSwvoDGPDtDPcYFovjLll+hJhWB9c ZBRykfPQ==; Received: from [10.9.9.72] (helo=submission01.runbox) by mailtransmit02.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1vx0MY-00056B-QN; Mon, 02 Mar 2026 11:18:54 +0100 Received: by submission01.runbox with esmtpsa [Authenticated ID (1493616)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1vx0MD-006y7o-Et; Mon, 02 Mar 2026 11:18:33 +0100 From: david.laight.linux@gmail.com To: Willy Tarreau , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , linux-kernel@vger.kernel.org, Cheng Li Cc: David Laight Subject: [PATCH v4 next 19/23] tools/nolibc/printf: Special case 0 and add support for %#x Date: Mon, 2 Mar 2026 10:18:11 +0000 Message-Id: <20260302101815.3043-20-david.laight.linux@gmail.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260302101815.3043-1-david.laight.linux@gmail.com> References: <20260302101815.3043-1-david.laight.linux@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: David Laight The output for %#x is almost the same as that for %p, both output in hexadecimal with a leading "0x". However for zero %#x should just output "0" (the same as decimal and ocal). For %p match glibc and output "(nil)" rather than "0x0" or "0". Add tests for "%#x", "% d", "%+d" and passing NULL to "%p". Signed-off-by: David Laight --- v4: Split into its' own patch. tools/include/nolibc/stdio.h | 38 ++++++++++++++------ tools/testing/selftests/nolibc/nolibc-test.c | 3 ++ 2 files changed, 30 insertions(+), 11 deletions(-) diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h index 5d75e8530ce2..ef8e7069d5cf 100644 --- a/tools/include/nolibc/stdio.h +++ b/tools/include/nolibc/stdio.h @@ -296,7 +296,7 @@ int fseek(FILE *stream, long offset, int whence) * - %% generates a single % * - %m outputs strerror(errno). * - %X outputs a..f the same as %x. - * - The modifiers [#-0] are currently ignored. + * - The modifiers [-0] are currently ignored. * - No support for precision or variable widths. * - No support for floating point or wide characters. * - Invalid formats are copied to the output buffer. @@ -410,8 +410,11 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list * so that 'X' can be allowed through. * 'X' gets treated and 'x' because _NOLIBC_PF_FLAG() returns the same * value for both. + * + * We need to check for "%p" or "%#x" later, merging here gives better code. + * But '#' collides with 'c' so shift right. */ - ch_flag = _NOLIBC_PF_FLAG(ch); + ch_flag = _NOLIBC_PF_FLAG(ch) | (flags & _NOLIBC_PF_FLAG('#')) >> 1; if (((ch >= 'a' && ch <= 'z') || ch == 'X') && _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', 'x', 'p', 's')) { /* 'long' is needed for pointer/string conversions and ltz lengths. @@ -470,17 +473,30 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list */ out = outbuf + 2; - /* Convert the number to ascii in the required base. */ - if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i', 'u')) { - /* Base 10 */ - len = u64toa_r(v, out); - } else { - /* Base 16 */ + if (v == 0) { + /* There are special rules for zero. */ if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'p')) { - /* "%p" needs "0x" prepending. */ - sign_prefix = 'x' | '0' << 8; + /* "%p" match glibc, precision is ignored */ + outstr = "(nil)"; + len = 5; + goto do_output; + } + /* All other formats (including "%#x") just output "0". */ + out[0] = '0'; + len = 1; + } else { + /* Convert the number to ascii in the required base. */ + if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i', 'u')) { + /* Base 10 */ + len = u64toa_r(v, out); + } else { + /* Base 16 */ + if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'p', '#' - 1)) { + /* "%p" and "%#x" need "0x" prepending. */ + sign_prefix = 'x' | '0' << 8; + } + len = u64toh_r(v, out); } - len = u64toh_r(v, out); } /* Add the 0, 1 or 2 ("0x") sign/prefix characters at the front. */ diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index a140c54e4d72..4267c69ec37c 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1825,6 +1825,7 @@ static int run_printf(int min, int max) CASE_TEST(string); EXPECT_VFPRINTF(1, "foo", "%s", "foo"); break; CASE_TEST(number); EXPECT_VFPRINTF(1, "1234", "%d", 1234); break; CASE_TEST(negnumber); EXPECT_VFPRINTF(1, "-1234", "%d", -1234); break; + CASE_TEST(num_sign); EXPECT_VFPRINTF(1, "| 1|+2|+3|+4|5|", "|% d|%+d|% +d|%+ d|%#d|", 1, 2, 3, 4, 5); break; CASE_TEST(unsigned); EXPECT_VFPRINTF(1, "12345", "%u", 12345); break; CASE_TEST(signed_max); EXPECT_VFPRINTF(1, "2147483647", "%i", ~0u >> 1); break; CASE_TEST(signed_min); EXPECT_VFPRINTF(1, "-2147483648", "%i", (~0u >> 1) + 1); break; @@ -1832,7 +1833,9 @@ static int run_printf(int min, int max) CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break; CASE_TEST(hex_nolibc); EXPECT_VFPRINTF(is_nolibc, "|f|d|", "|%x|%X|", 0xf, 0xd); break; CASE_TEST(hex_libc); EXPECT_VFPRINTF(!is_nolibc, "|f|D|", "|%x|%X|", 0xf, 0xd); break; + CASE_TEST(hex_alt); EXPECT_VFPRINTF(1, "|0x1| 0x2| 0|", "|%#x|%#5x|%#5x|", 1, 2, 0); break; CASE_TEST(pointer); EXPECT_VFPRINTF(1, "0x1", "%p", (void *) 0x1); break; + CASE_TEST(pointer_NULL); EXPECT_VFPRINTF(1, "(nil)", "%p", (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; -- 2.39.5