Commit 91e901c6 authored by Michael Bommarito's avatar Michael Bommarito Committed by Johannes Berg
Browse files

um: drivers: call kernel_strrchr() explicitly in cow_user.c 



Building ARCH=um on glibc >= 2.43 fails:

  arch/um/drivers/cow_user.c: error: implicit declaration of
  function 'strrchr' [-Wimplicit-function-declaration]

glibc 2.43's C23 const-preserving strrchr() macro does not survive
UML's global -Dstrrchr=kernel_strrchr remap from arch/um/Makefile.
Call kernel_strrchr() directly in cow_user.c so the source no longer
depends on the -D rewrite.

Fixes: 2c51a4bc ("um: fix strrchr() problems")
Suggested-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-6
Assisted-by: Codex:gpt-5-4
Signed-off-by: default avatarMichael Bommarito <michael.bommarito@gmail.com>
Link: https://patch.msgid.link/20260408070102.2325572-1-michael.bommarito@gmail.com


[remove unnecessary 'extern']
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 8aae2da6

arch/um/drivers/cow_user.c

+7 −1
Original line number Diff line number Diff line
@@ -15,6 +15,12 @@ 
#include "cow.h"

#include "cow_sys.h"



/*

 * arch/um/Makefile remaps strrchr to kernel_strrchr; call the kernel

 * name directly to avoid glibc >= 2.43's C23 strrchr macro.

 */

char *kernel_strrchr(const char *, int);



#define PATH_LEN_V1 256



/* unsigned time_t works until year 2106 */
@@ -153,7 +159,7 @@ static int absolutize(char *to, int size, char *from) 
			   errno);

		return -1;

	}

	slash = strrchr(from, '/');

	slash = kernel_strrchr(from, '/');

	if (slash != NULL) {

		*slash = '\0';

		if (chdir(from)) {