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From: david.laight.linux@gmail.com
To: "Willy Tarreau" <w@1wt.eu>,
	"Thomas Weißschuh" <linux@weissschuh.net>,
	linux-kernel@vger.kernel.org, "Cheng Li" <lechain@gmail.com>
Cc: David Laight <david.laight.linux@gmail.com>
Subject: [PATCH v3 next 12/17] tools/nolibc/printf: Handle "%s" with the numeric formats
Date: Mon, 23 Feb 2026 10:17:30 +0000	[thread overview]
Message-ID: <20260223101735.2922-13-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20260223101735.2922-1-david.laight.linux@gmail.com>

From: David Laight <david.laight.linux@gmail.com>

Avoids the extra va_arg() call with is non-trivial on a lot of
modern ABI.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---

Changes for v3: 
- Moved to its own patch (part of patch 7 in v2)..
- Fix 32bit compile.

 tools/include/nolibc/stdio.h | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 6cb106367e3b..6dd27473ab7f 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -412,13 +412,13 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
 		 */
 		ch_flag = _NOLIBC_PF_FLAG(ch);
 		if (((ch >= 'a' && ch <= 'z') || ch == 'X') &&
-		    _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', 'x', 'p')) {
-			/* 'long' is needed for pointer conversions and ltz lengths.
+		    _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', '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.
 			 */
 			if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag | (flags & ~_NOLIBC_PF_FLAG('p')),
-						     'p', 'l', 't', 'z')) {
+						     'p', 's', 'l', 't', 'z')) {
 				v = va_arg(args, unsigned long);
 				signed_v = (long)v;
 			} else if (_NOLIBC_PF_FLAGS_CONTAIN(flags, 'j', 'q')) {
@@ -437,6 +437,15 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
 				goto do_output;
 			}
 
+			if (ch == 's') {
+				/* "%s" - character string. */
+				outstr = (const char  *)(uintptr_t)v;
+				if (!outstr) {
+					outstr = "(null)";
+				}
+				goto do_strlen_output;
+			}
+
 			out = outbuf;
 
 			if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i')) {
@@ -465,13 +474,6 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
 			goto do_strlen_output;
 		}
 
-		if (ch == 's') {
-			outstr = va_arg(args, char *);
-			if (!outstr)
-				outstr="(null)";
-			goto do_strlen_output;
-		}
-
 		if (ch == 'm') {
 			outstr = strerror(errno);
 			goto do_strlen_output;
-- 
2.39.5


  parent reply	other threads:[~2026-02-23 11:00 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-23 10:17 [PATCH v3 next 00/17] Enhance printf() david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 01/17] tools/nolibc: Add _NOLIBC_OPTIMIZER_HIDE_VAR() to compiler.h david.laight.linux
2026-02-25 21:25   ` Thomas Weißschuh
2026-02-25 22:17     ` David Laight
2026-02-25 22:24       ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 02/17] tools/nolibc: Optimise and common up the number to ascii functions david.laight.linux
2026-02-25 21:40   ` Thomas Weißschuh
2026-02-25 22:09     ` David Laight
2026-02-23 10:17 ` [PATCH v3 next 03/17] selftests/nolibc: Fix build with host headers and libc david.laight.linux
2026-02-25 21:24   ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 04/17] selftests/nolibc: Improve reporting of vfprintf() errors david.laight.linux
2026-02-25 21:56   ` Thomas Weißschuh
2026-02-26 10:12     ` David Laight
2026-02-26 21:39       ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 05/17] tools/nolibc: Implement strerror() in terms of strerror_r() david.laight.linux
2026-02-25 22:09   ` Thomas Weißschuh
2026-02-25 22:58     ` David Laight
2026-02-23 10:17 ` [PATCH v3 next 06/17] tools/nolibc/printf: Change variables 'c' to 'ch' and 'tmpbuf[]' to 'outbuf[]' david.laight.linux
2026-02-25 22:23   ` Thomas Weißschuh
2026-02-23 10:17 ` [PATCH v3 next 07/17] tools/nolibc/printf: Move snprintf length check to callback david.laight.linux
2026-02-25 22:37   ` Thomas Weißschuh
2026-02-25 23:12     ` David Laight
2026-02-26 21:29       ` Thomas Weißschuh
2026-02-26 22:11         ` David Laight
2026-02-23 10:17 ` [PATCH v3 next 08/17] tools/nolibc/printf: Output pad characters in 16 byte chunks david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 09/17] tools/nolibc/printf: Simplify __nolibc_printf() david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 10/17] tools/nolibc/printf: Use goto and reduce indentation david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 11/17] tools/nolibc/printf: Use bit-masks to hold requested flag, length and conversion chars david.laight.linux
2026-02-23 10:17 ` david.laight.linux [this message]
2026-02-23 10:17 ` [PATCH v3 next 13/17] tools/nolibc/printf: Add support for conversion flags david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 14/17] tools/nolibc/printf: Add support for left aligning fields david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 15/17] tools/nolibc/printf: Add support for zero padding and field precision david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 16/17] tools/nolibc/printf: Add support for octal output david.laight.linux
2026-02-23 10:17 ` [PATCH v3 next 17/17] selftests/nolibc: Use printf variable field widths and precisions david.laight.linux

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