From ce1fb41a6c33e5708b477e8b34c0aa49d6fc79ec Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Fri, 14 Jun 2024 09:30:28 +0200
Subject: [PATCH] kvprintf(): Fix '+' conversion handling

For example, printf("%+i", 1) prints "+1".  However, kvprintf() did
print just "1" for this example.  According to PRINTF(3):

  A sign must always be placed before a number produced by a signed
  conversion.

For "%+r" radix conversions, keep the "+" handling as it is, since this
is a non-standard conversion.  For "%+p" pointer conversions, continue
to ignore the sign modifier to be in line with libc.

This change allows to support the ' conversion modifier in the future.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1310
---
 cpukit/dev/iovprintf.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/cpukit/dev/iovprintf.c b/cpukit/dev/iovprintf.c
index 4394e4f052..a30e8633fc 100644
--- a/cpukit/dev/iovprintf.c
+++ b/cpukit/dev/iovprintf.c
@@ -95,9 +95,9 @@ _IO_Vprintf(IO_Put_char put_char, void *arg, char const *fmt, va_list ap)
 	char nbuf[MAXNBUF];
 	const char *p, *percent, *q;
 	u_char *up;
-	int ch, n;
+	int ch, n, sign;
 	uintmax_t num;
-	int base, lflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
+	int base, lflag, tmp, width, ladjust, sharpflag, dot;
 	int cflag, hflag, jflag;
 	RTEMS_STATIC_ASSERT(sizeof(intmax_t) == sizeof(long long), _IO_Vprintf_j);
 #if __SIZEOF_PTRDIFF_T__ == __SIZEOF_LONG__
@@ -128,7 +128,7 @@ _IO_Vprintf(IO_Put_char put_char, void *arg, char const *fmt, va_list ap)
 			PCHAR(ch);
 		}
 		percent = fmt - 1;
-		lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
+		lflag = 0; ladjust = 0; sharpflag = 0;
 		sign = 0; dot = 0; dwidth = 0; upper = 0;
 		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
 reswitch:	switch (ch = (u_char)*fmt++) {
@@ -139,7 +139,7 @@ reswitch:	switch (ch = (u_char)*fmt++) {
 			sharpflag = 1;
 			goto reswitch;
 		case '+':
-			sign = 1;
+			sign = '+';
 			goto reswitch;
 		case '-':
 			ladjust = 1;
@@ -205,7 +205,6 @@ reswitch:	switch (ch = (u_char)*fmt++) {
 		case 'd':
 		case 'i':
 			base = 10;
-			sign = 1;
 			goto handle_sign;
 		case 'h':
 			if (hflag) {
@@ -267,13 +266,11 @@ reswitch:	switch (ch = (u_char)*fmt++) {
 			goto handle_nosign;
 		case 'y':
 			base = 16;
-			sign = 1;
 			goto handle_sign;
 		case 'z':
 			zflag = 1;
 			goto reswitch;
 handle_nosign:
-			sign = 0;
 			if (jflag)
 				num = va_arg(ap, uintmax_t);
 #if __SIZEOF_PTRDIFF_T__ != __SIZEOF_LONG__
@@ -312,11 +309,11 @@ handle_sign:
 				num = (signed char)va_arg(ap, int);
 			else
 				num = va_arg(ap, int);
-number:
-			if (sign && (intmax_t)num < 0) {
-				neg = 1;
+			if ((intmax_t)num < 0) {
+				sign = '-';
 				num = -(intmax_t)num;
 			}
+number:
 			p = ksprintn(nbuf, num, base, &n, upper);
 			tmp = 0;
 			if (sharpflag && num != 0) {
@@ -325,7 +322,7 @@ number:
 				else if (base == 16)
 					tmp += 2;
 			}
-			if (neg)
+			if (sign)
 				tmp++;
 
 			if (!ladjust && padc == '0')
@@ -335,8 +332,8 @@ number:
 			if (!ladjust)
 				while (width-- > 0)
 					PCHAR(' ');
-			if (neg)
-				PCHAR('-');
+			if (sign)
+				PCHAR(sign);
 			if (sharpflag && num != 0) {
 				if (base == 8) {
 					PCHAR('0');