[PATCH 21/28] NFS: nfsroot: Refactor root_nfs_cat() to use snprintf()

Wed, 16 Sep 2026 00:35:59 -0700 

root_nfs_cat() computes the length of "dest" with strlen(), but then uses
up to two strlcat() calls to append a comma separator and "src",
rescanning "dest" each time.

In preparation for removing the deprecated strlcat() API[1], use the
already-computed length and a single snprintf() call to append the
optional comma and "src", returning -1 if the result is truncated.

Link: https://github.com/KSPP/linux/issues/370 [1]
Cc: [email protected]
Assisted-by: CoPilot:Claude-3.5-Sonnet [editor_update_file, 
make_kernel_build_single_file]
Signed-off-by: Bill Wendling <[email protected]>
---
Cc: Russell King <[email protected]>
Cc: Huacai Chen <[email protected]>
Cc: WANG Xuerui <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ian Abbott <[email protected]>
Cc: H Hartley Sweeten <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Thomas Zimmermann <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Simona Vetter <[email protected]>
Cc: Matthew Brost <[email protected]>
Cc: "Thomas Hellström" <[email protected]>
Cc: Rodrigo Vivi <[email protected]>
Cc: Dmitry Torokhov <[email protected]>
Cc: Matthias Schwarzott <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
Cc: Tony Nguyen <[email protected]>
Cc: Przemek Kitszel <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Jakub Kicinski <[email protected]>
Cc: Paolo Abeni <[email protected]>
Cc: Arend van Spriel <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Saravana Kannan <[email protected]>
Cc: Krzysztof Kozlowski <[email protected]>
Cc: Sylwester Nawrocki <[email protected]>
Cc: Peter Griffin <[email protected]>
Cc: Alim Akhtar <[email protected]>
Cc: Linus Walleij <[email protected]>
Cc: Anil Gurumurthy <[email protected]>
Cc: Sudarsana Kalluru <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: Trond Myklebust <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: Mike Marshall <[email protected]>
Cc: Martin Brandenburg <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jiri Pirko <[email protected]>
Cc: Simon Horman <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: NeilBrown <[email protected]>
Cc: Olga Kornievskaia <[email protected]>
Cc: Dai Ngo <[email protected]>
Cc: Tom Talpey <[email protected]>
Cc: Jaroslav Kysela <[email protected]>
Cc: Takashi Iwai <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: "Mike Rapoport (Microsoft)" <[email protected]>
Cc: Kanglong Wang <[email protected]>
Cc: Tiezhu Yang <[email protected]>
Cc: Qiang Ma <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Pengpeng Hou <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Breno Leitao <[email protected]>
Cc: Thorsten Blum <[email protected]>
Cc: Harshit Mogalapalli <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Lyude Paul <[email protected]>
Cc: Ashutosh Desai <[email protected]>
Cc: Imre Deak <[email protected]>
Cc: Dmitry Baryshkov <[email protected]>
Cc: Johan Hovold <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Miri Korenblit <[email protected]>
Cc: Alexander Stein <[email protected]>
Cc: Cryolitia PukNgae <[email protected]>
Cc: Jiaming Zhang <[email protected]>
Cc: Will Porter <[email protected]>
Cc: Cen Zhang <[email protected]>
Cc: "Cássio Gabriel" <[email protected]>
Cc: Rong Zhang <[email protected]>
Cc: Arun Raghavan <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
---
 fs/nfs/nfsroot.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 432612d22437..a28208414aec 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -173,12 +173,15 @@ static int __init root_nfs_cat(char *dest, const char 
*src,
                               const size_t destlen)
 {
        size_t len = strlen(dest);
+       int ret;
 
-       if (len && dest[len - 1] != ',')
-               if (strlcat(dest, ",", destlen) >= destlen)
-                       return -1;
+       if (len >= destlen)
+               return -1;
 
-       if (strlcat(dest, src, destlen) >= destlen)
+       ret = snprintf(dest + len, destlen - len, "%s%s",
+                      (len && dest[len - 1] != ',') ? "," : "", src);
+
+       if (ret < 0 || ret >= destlen - len)
                return -1;
        return 0;
 }
-- 
2.55.0.1032.g73a4cd73de-goog

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