linux-kernel - [PATCH 1/1] tools/nolibc/string: export strlen()

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Date: Fri, 26 Jan 2024 15:24:11 +0100
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 1/1] tools/nolibc/string: export strlen()

As with commit 8d304a374023, "tools/nolibc/string: export memset() and
memmove()", gcc -Os without -ffreestanding may fail to compile with:

	cc -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib -lgcc -c test.c -o test.o
	cc test.o -fno-asynchronous-unwind-tables -fno-ident -s -Os -nostdlib -lgcc  -static -o test
	/usr/bin/ld: test.o: in function `main':
	test.c:(.text.startup+0x32): undefined reference to `strlen'
	collect2: error: ld returned 1 exit status

As on the aforementioned commit, this patch adds a section to export
this function so compilation works on those cases too.

Signed-off-by: Rodrigo Campos <rodrigo@...g.com.ar>
---
 tools/include/nolibc/string.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
index a01c69dd495f..ed15c22b1b2a 100644
--- a/tools/include/nolibc/string.h
+++ b/tools/include/nolibc/string.h
@@ -123,7 +123,7 @@ char *strcpy(char *dst, const char *src)
  * thus itself, hence the asm() statement below that's meant to disable this
  * confusing practice.
  */
-static __attribute__((unused))
+__attribute__((weak,unused,section(".text.nolibc_strlen")))
 size_t strlen(const char *str)
 {
 	size_t len;
-- 
2.43.0