linux-kernel - [PATCH v3 3/4] tools/nolibc: Fix strlcpy() return code and size usage

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Message-ID: <20240218195110.1386840-4-rodrigo@sdfg.com.ar>
Date: Sun, 18 Feb 2024 16:51:05 -0300
From: Rodrigo Campos <rodrigo@...g.com.ar>
To: Willy Tarreau <w@....eu>,
	Thomas Weißschuh <linux@...ssschuh.net>
Cc: linux-kernel@...r.kernel.org,
	Rodrigo Campos <rodrigo@...g.com.ar>
Subject: [PATCH v3 3/4] tools/nolibc: Fix strlcpy() return code and size usage

The return code should always be strlen(src), and we should copy at most
size-1 bytes.

While we are there, make sure to null-terminate the dst buffer if we
copied something.

Signed-off-by: Rodrigo Campos <rodrigo@...g.com.ar>
---
 tools/include/nolibc/string.h | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
index cc51fd6b63d0..565230a4ad47 100644
--- a/tools/include/nolibc/string.h
+++ b/tools/include/nolibc/string.h
@@ -219,16 +219,18 @@ static __attribute__((unused))
 size_t strlcpy(char *dst, const char *src, size_t size)
 {
 	size_t len;
-	char c;
 
-	for (len = 0;;) {
-		c = src[len];
-		if (len < size)
-			dst[len] = c;
-		if (!c)
-			break;
-		len++;
+	for (len = 0; len < size; len++) {
+		dst[len] = src[len];
+		if (!dst[len])
+			return len;
 	}
+	if (size)
+		dst[size-1] = '\0';
+
+	while (src[len])
+		len++;
+
 	return len;
 }
 
-- 
2.43.0