Re: [PATCH] Makefile: add USE_PIE

[Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>]

On Sun,  5 May 2024 15:39:23 +0200
Fabrice Fontaine <fontaine.fabrice@gmail.com> wrote:

> Do not hardcode -pie and allow the user to drop it (e.g. PIE could be
> enabled or disabled by the buildsystem such as buildroot)

What about -fPIE? It is in CWFLAGS but it is configurable.
Do you specify you own set of CWFLAGS?

> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> ---
>  Makefile | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/Makefile b/Makefile
> index 7c221a89..a5269687 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -137,7 +137,11 @@ LDFLAGS = -Wl,-z,now,-z,noexecstack
>  # If you want a static binary, you might uncomment these
>  # LDFLAGS += -static
>  # STRIP = -s
> -LDLIBS = -ldl -pie
> +LDLIBS = -ldl
> +USE_PIE = 1
> +ifdef USE_PIE
> +LDLIBS += -pie
> +endif
>  
>  # To explicitly disable libudev, set -DNO_LIBUDEV in CXFLAGS
>  ifeq (, $(findstring -DNO_LIBUDEV,  $(CXFLAGS)))

AFAIK -pie is not library specifier, it is a a gcc linking setting so having it
in LDLIBS seems weird to me. What about making LDFLAGS configurable?

diff --git a/Makefile b/Makefile
index 7c221a891181..adac7905ab57 100644
--- a/Makefile
+++ b/Makefile
@@ -132,12 +132,12 @@ CFLAGS += -DUSE_PTHREADS
 MON_LDFLAGS += -pthread
 endif

-LDFLAGS = -Wl,-z,now,-z,noexecstack
+LDFLAGS ?= -pie -Wl,-z,now,-z,noexecstack

 # If you want a static binary, you might uncomment these
 # LDFLAGS += -static
 # STRIP = -s
-LDLIBS = -ldl -pie
+LDLIBS = -ldl

It works on my setup however I'm not deeply sure if it is correct.
Let me know if it resolves your issue. I would prefer to give possibility to
customize LDFLAGS rather than add ifdef to Makefile.

Thanks,
Mariusz