[PATCH] NFS: nfsroot: replace strlcat() with snprintf()

In preparation for removing the deprecated strlcat() API[1], replace its
uses in root_nfs_cat() with snprintf().

Build the separator and source string in a single call using the
remaining space in the destination buffer. snprintf() returns the length
it would have written excluding the terminating NUL, so comparing the
return value against the remaining buffer space preserves the existing
truncation check.

Link: https://github.com/KSPP/linux/issues/370 [1]
Signed-off-by: Mariia Nikitash <[email protected]>
---
 fs/nfs/nfsroot.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 432612d22437..e951fe731679 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -173,12 +173,12 @@ static int __init root_nfs_cat(char *dest, const char *src,
 			       const size_t destlen)
 {
 	size_t len = strlen(dest);
+	size_t remaining = destlen - len;
+	const char *sep = "";
 
 	if (len && dest[len - 1] != ',')
-		if (strlcat(dest, ",", destlen) >= destlen)
-			return -1;
-
-	if (strlcat(dest, src, destlen) >= destlen)
+		sep = ",";
+	if (snprintf(dest + len, remaining, "%s%s", sep, src) >= remaining)
 		return -1;
 	return 0;
 }
-- 
2.55.0.679.g6767b8d81c-goog