[PATCH] s390/string: Remove strlcat() implementation

[PATCH] s390/string: Remove strlcat() implementation

[Heiko Carstens]

strlcat() shouldn't be used anymore (see fortify-string.h), and will be
deprecated / removed sooner or later [1].

Therefore remove the s390 implementation of strlcat() in favor of the
generic variant.

[1] https://lore.kernel.org/all/20260514160719.105084-3-manuelebner@mailbox.org/

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/include/asm/string.h |  2 --
 arch/s390/lib/string.c         | 26 --------------------------
 2 files changed, 28 deletions(-)

diff --git a/arch/s390/include/asm/string.h b/arch/s390/include/asm/string.h
index 238e721e5a22..378f85304ef5 100644
--- a/arch/s390/include/asm/string.h
+++ b/arch/s390/include/asm/string.h
@@ -26,7 +26,6 @@ void *memmove(void *dest, const void *src, size_t n);
 #define __HAVE_ARCH_MEMSCAN	/* inline & arch function */
 #define __HAVE_ARCH_STRCAT	/* inline & arch function */
 #define __HAVE_ARCH_STRCMP	/* arch function */
-#define __HAVE_ARCH_STRLCAT	/* arch function */
 #define __HAVE_ARCH_STRLEN	/* inline & arch function */
 #define __HAVE_ARCH_STRNCAT	/* arch function */
 #define __HAVE_ARCH_STRNLEN	/* inline & arch function */
@@ -38,7 +37,6 @@ void *memmove(void *dest, const void *src, size_t n);
 /* Prototypes for non-inlined arch strings functions. */
 int memcmp(const void *s1, const void *s2, size_t n);
 int strcmp(const char *s1, const char *s2);
-size_t strlcat(char *dest, const char *src, size_t n);
 char *strncat(char *dest, const char *src, size_t n);
 char *strstr(const char *s1, const char *s2);
 #endif /* !defined(CONFIG_KASAN) && !defined(CONFIG_KMSAN) */
diff --git a/arch/s390/lib/string.c b/arch/s390/lib/string.c
index 757f58960198..a48e5bb3c15f 100644
--- a/arch/s390/lib/string.c
+++ b/arch/s390/lib/string.c
@@ -104,32 +104,6 @@ char *strcat(char *dest, const char *src)
 EXPORT_SYMBOL(strcat);
 #endif
 
-/**
- * strlcat - Append a length-limited, %NUL-terminated string to another
- * @dest: The string to be appended to
- * @src: The string to append to it
- * @n: The size of the destination buffer.
- */
-#ifdef __HAVE_ARCH_STRLCAT
-size_t strlcat(char *dest, const char *src, size_t n)
-{
-	size_t dsize = __strend(dest) - dest;
-	size_t len = __strend(src) - src;
-	size_t res = dsize + len;
-
-	if (dsize < n) {
-		dest += dsize;
-		n -= dsize;
-		if (len >= n)
-			len = n - 1;
-		dest[len] = '\0';
-		memcpy(dest, src, len);
-	}
-	return res;
-}
-EXPORT_SYMBOL(strlcat);
-#endif
-
 /**
  * strncat - Append a length-limited, %NUL-terminated string to another
  * @dest: The string to be appended to
-- 
2.51.0

Re: [PATCH] s390/string: Remove strlcat() implementation

[Alexander Gordeev]

On Fri, May 22, 2026 at 04:31:11PM +0200, Heiko Carstens wrote:
> strlcat() shouldn't be used anymore (see fortify-string.h), and will be
> deprecated / removed sooner or later [1].
> 
> Therefore remove the s390 implementation of strlcat() in favor of the
> generic variant.
> 
> [1] https://lore.kernel.org/all/20260514160719.105084-3-manuelebner@mailbox.org/
> 
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
> ---
>  arch/s390/include/asm/string.h |  2 --
>  arch/s390/lib/string.c         | 26 --------------------------
>  2 files changed, 28 deletions(-)

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>

and pushed.

Thanks!

Re: [PATCH] s390/string: Remove strlcat() implementation

[David Laight]

On Fri, 22 May 2026 16:31:11 +0200
Heiko Carstens <hca@linux.ibm.com> wrote:

> strlcat() shouldn't be used anymore (see fortify-string.h), and will be
> deprecated / removed sooner or later [1].
> 
....
>  #define __HAVE_ARCH_STRCAT	/* inline & arch function */
...
>  #define __HAVE_ARCH_STRNCAT	/* arch function */

Those two should probably have gone first ...

-- David

Re: [PATCH] s390/string: Remove strlcat() implementation

[Heiko Carstens]

On Wed, May 27, 2026 at 02:03:58PM +0100, David Laight wrote:
> On Fri, 22 May 2026 16:31:11 +0200
> Heiko Carstens <hca@linux.ibm.com> wrote:
> 
> > strlcat() shouldn't be used anymore (see fortify-string.h), and will be
> > deprecated / removed sooner or later [1].
> > 
> ....
> >  #define __HAVE_ARCH_STRCAT	/* inline & arch function */
> ...
> >  #define __HAVE_ARCH_STRNCAT	/* arch function */
> 
> Those two should probably have gone first ...

Yes, except that we need strcat() for the boot code - there we cannot use the
generic variant. Of course it would be possible to copy the existing strcat()
implementation to the boot code, rename it to e.g. strconcatenate(), and
strcat()/strncat() would be gone, at least grep wise :)