# \[PATCH\] test-lib.sh: Use GLIBC\_TUNABLES instead of MALLOC\_CHECK\_ on glibc \>= 2.34

- From: Elia Pinto \<hidden\>
- Date: 2022-02-28 16:08:47 
- List: git
- Page: https://ratatoskr.run/git/2022/02/7932094
- Thread: https://ratatoskr.run/git/2022/02/7932094/t.md

```text
In glibc >= 2.34 MALLOC_CHECK_ and MALLOC_PERTURB_ environment
variables have been replaced by GLIBC_TUNABLES.  Also the new
glibc requires that you preload a library called libc_malloc_debug.so
to get these features.

Using the ordinary glibc system variable detect if this is glibc >= 2.34 and
use GLIBC_TUNABLES and the new library.

This patch was inspired by a Richard W.M. Jones ndbkit patch

Signed-off-by: Elia Pinto <redacted>
---
 t/test-lib.sh | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/t/test-lib.sh b/t/test-lib.sh
index e4716b0b86..136614ac8c 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -517,12 +517,27 @@ then
 		: nothing
 	}
 else
+	if type -p getconf >/dev/null 2>&1; then
+		_GLIBC_VERSION="$(getconf GNU_LIBC_VERSION 2>/dev/null | awk '{ print $2 }')"
+		if [ -n "$_GLIBC_VERSION" -a $(expr "$_GLIBC_VERSION" \>= "2.34") ]; then
+			_HAVE_GLIBC_234="yes"
+		fi
+	fi
 	setup_malloc_check () {
-		MALLOC_CHECK_=3	MALLOC_PERTURB_=165
-		export MALLOC_CHECK_ MALLOC_PERTURB_
+			if test "x$_HAVE_GLIBC_234" = xyes ; then
+				LD_PRELOAD="libc_malloc_debug.so.0" GLIBC_TUNABLES="glibc.malloc.check=1:glibc.malloc.perturb=165"
+				export LD_PRELOAD GLIBC_TUNABLES
+			else
+				MALLOC_CHECK_=3	MALLOC_PERTURB_=165
+				export MALLOC_CHECK_ MALLOC_PERTURB_
+			fi
 	}
 	teardown_malloc_check () {
-		unset MALLOC_CHECK_ MALLOC_PERTURB_
+			if test "x$_HAVE_GLIBC_234" = xyes ; then
+				unset LD_PRELOAD GLIBC_TUNABLES
+			else
+				unset MALLOC_CHECK_ MALLOC_PERTURB_
+			fi
 	}
 fi
 
-- 
2.35.1

```