From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailtransmit05.runbox.com (mailtransmit05.runbox.com [185.226.149.38]) (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 021021607A4 for ; Mon, 23 Feb 2026 11:15:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.38 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771845332; cv=none; b=D1WzNDgNFjelb5AE904ItD0xTGpKbFqklmAEjrqIKB3e7Jcz8X5ydThVU0Vq83BsuXUVLu300PTbKs/rbldQ1iKbOWok5Dy42ZFJWmcKn5raITbw0u+5+OksRYAR738aUrUzb6/y/cbIc90kcARa6fGrdxLYtmMpl2M7m4WLW9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771845332; c=relaxed/simple; bh=QkmDvNK7zuUS0Ngq+JC24ZM4/OVeg48+MUQmJ17wLss=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=jGwPNw6RuHYPQRd/RTqk7PvRbg4T9jQccl2RgTQxvcAtoXErHyPTDH+Xp0X4YHqDjex+pue5dt1qRbyNnpdJwCV1j7k0e/OB3PuaDTuMeOVjKiC+KLtmTLW8ySJgQOm9QyB2VYfJKOv54ILJKOM7zwMaaU/gsyAGmldqZLEA/EE= 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=YwkfeaGc; arc=none smtp.client-ip=185.226.149.38 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="YwkfeaGc" Received: from mailtransmit03.runbox ([10.9.9.163] helo=aibo.runbox.com) by mailtransmit05.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1vuT18-00GoCW-BB; Mon, 23 Feb 2026 11:18:18 +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=351uFpNMb6F6EQ8Mfzu1N3JEHx/Kky76IuxraG6rJjc=; b=YwkfeaGc9nfz5W8Fs1mmyuA1EP bYmu2lhZY7nYuAt/1B3Tkoc5exwISI/O3BiUc+q8y4XKfMlYy9wxPpk58DJ3DVRKB29IynmHKqjsg K7yncWhJ/Sfbbh9SwS9VZH6o1XNQokd0x+IQ/5Ba7Q7fSvIR/AT+r9yhe3Z3RlcdVC3Z+mLuf0fT+ 7aZ1GMB82G8h4FV0x6VCqdqQnanVNHt/KgD+tCeQMkac07kte42M7HX+PhqDjX69WbOWepOmcb9os HISXvzWQMtb2+iy90Z4QiM+0NOCkon0obB11uIvSIVIAcY3Vww75Y389SxTsHEHJh+5od8jYV2WKm 5eqAoCFw==; Received: from [10.9.9.73] (helo=submission02.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1vuT17-0001Qq-Qs; Mon, 23 Feb 2026 11:18:17 +0100 Received: by submission02.runbox with esmtpsa [Authenticated ID (1493616)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1vuT16-006AjD-MR; Mon, 23 Feb 2026 11:18:16 +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 v3 next 16/17] tools/nolibc/printf: Add support for octal output Date: Mon, 23 Feb 2026 10:17:34 +0000 Message-Id: <20260223101735.2922-17-david.laight.linux@gmail.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260223101735.2922-1-david.laight.linux@gmail.com> References: <20260223101735.2922-1-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 Octal output isn't often used, but adding it costs very little. Supporting "%#o" is mildly annoying, it has to add a leading '0' if there isn't one present. In simple cases this is the same as adding a sign of '0' - but that adds an extra '0' in a few places. So you need 3 tests, %o, # and no leading '0' (which can only be checked after the zero pad for precision). If all the test are deferred until after zero padding then too many values are 'live' across the call to _nolibc_u64toa_base() and get spilled to stack. Hence the check that ignores the 'sign' if it is the same as the first character of the output string. Add tests for octal output. Signed-off-by: David Laight --- New patch for v3. Relies on the changes to u64toa_r() etc in stdlib.h (patch 2). tools/include/nolibc/stdio.h | 50 ++++++++++++++------ tools/testing/selftests/nolibc/nolibc-test.c | 3 ++ 2 files changed, 38 insertions(+), 15 deletions(-) diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h index cc2870a6a7cb..e6aca894bf71 100644 --- a/tools/include/nolibc/stdio.h +++ b/tools/include/nolibc/stdio.h @@ -292,7 +292,7 @@ int fseek(FILE *stream, long offset, int whence) /* printf(). Supports most of the normal integer and string formats. - * - %[#0-+ ][width|*[.precision|*}][{l,t,z,ll,L,j,q}]{c,d,i,u,x,X,p,s,m,%} + * - %[#0-+ ][width|*[.precision|*}][{l,t,z,ll,L,j,q}]{c,d,i,u,o,x,X,p,s,m,%} * - %% generates a single % * - %m outputs strerror(errno). * - %X outputs a..f the same as %x. @@ -426,7 +426,7 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list */ 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')) { + _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', 'o', 'x', 'p', 's')) { /* 'long' is needed for pointer/string conversions and ltz lengths. * A single test can be used provided 'p' (the same bit as '0') * is masked from flags. @@ -477,12 +477,19 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list } else if (_NOLIBC_PF_FLAGS_CONTAIN(flags, ' ')) { sign_prefix = ' '; } + } else { + /* "#o" requires that the output always starts with a '0'. + * This needs another check after any zero padding to avoid + * adding an extra leading '0'. + */ + if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'o') && + _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, '#' - 1)) + sign_prefix = '0'; } /* The value is converted offset into the buffer so that * 31 zero pad characters and the sign/prefix can be added in front. - * The longest digit string is 22 + 1 for octal conversions, the - * space is reserved even though octal isn't currently supported. + * The longest digit string is 22 + 1 for octal conversions. */ out = outbuf + 2 + 31; @@ -495,7 +502,7 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list goto do_output; } if (!precision) { - /* Explicit %nn.0d, no digits output */ + /* Explicit %nn.0d, no digits output (except for %#.0o) */ len = 0; goto prepend_sign; } @@ -504,17 +511,23 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list len = 1; } else { /* Convert the number to ascii in the required base. */ + unsigned long long recip; + unsigned int base; if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i', 'u')) { - /* Base 10 */ - len = u64toa_r(v, out); + base = 10; + recip = _NOLIBC_U64TOA_RECIP(10); + } else if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'o')) { + base = 8; + recip = _NOLIBC_U64TOA_RECIP(8); } else { - /* Base 16 */ + base = 16; + recip = _NOLIBC_U64TOA_RECIP(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 = _nolibc_u64toa_base(v, out, base, recip); } /* Add zero padding */ @@ -545,13 +558,20 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list } } + /* %#o has set sign_prefix to '0', but we don't want so add an extra + * leading zero here. + * Since the only other byte values of sign_prefix are ' ', '+' and '-' + * it is enough to check that out[] doesn't already start with sign_prefix. + */ + if (sign_prefix != *out) { prepend_sign: - /* Add the 0, 1 or 2 ("0x") sign/prefix characters at the front. */ - for (; sign_prefix; sign_prefix >>= 8) { - /* Force gcc to increment len inside the loop. */ - _NOLIBC_OPTIMIZER_HIDE_VAR(len); - len++; - *--out = sign_prefix; + /* Add the 0, 1 or 2 ("0x") sign/prefix characters at the front. */ + for (; sign_prefix; sign_prefix >>= 8) { + /* Force gcc to increment len inside the loop. */ + _NOLIBC_OPTIMIZER_HIDE_VAR(len); + len++; + *--out = sign_prefix; + } } outstr = out; goto do_output; diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index e0cfe8d12ed1..b1f27fb1dd74 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -1839,6 +1839,9 @@ static int run_printf(int min, int max) CASE_TEST(unsigned_max); EXPECT_VFPRINTF(1, "4294967295", "%u", ~0u); break; CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break; CASE_TEST(char); EXPECT_VFPRINTF(1, "|c|d| e|", "|%c|%.0c|%4c|", 'c', 'd', 'e'); break; + CASE_TEST(octal); EXPECT_VFPRINTF(1, "|17| 0033||", "|%o|%6.4o|%.0o|", 017, 033, 0); break; + CASE_TEST(octal_max); EXPECT_VFPRINTF(1, "1777777777777777777777", "%llo", ~0ULL); break; + CASE_TEST(octal_alt); EXPECT_VFPRINTF(1, "|0|01|02|034|0|", "|%#o|%#o|%#02o|%#02o|%#.0o|", 0, 1, 2, 034, 0); 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(pointer); EXPECT_VFPRINTF(1, "0x1", "%p", (void *) 0x1); break; -- 2.39.5