[LTP] [PATCH] include: undefine _LINUX_TYPES_H if including sys/capability.h

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello,

Li Wang <liwang@redhat.com> writes:

> Richard Palethorpe <rpalethorpe@suse.de> wrote:
>
> ...
>> >  #ifdef HAVE_SYS_CAPABILITY_H
>> >  # include <sys/capability.h>
>> > +# undef _LINUX_TYPES_H
>>
>> My concern here is if linux/types.h has already been included. Then this
>> could cause a redefinition error if it is included again.
>>
>
> Hmm, it looks tricky to solve this, because I didn't find a macro to show
> version in libcap files.
>
> Another method I can think of is to build a small program to check if that
> libcap version is newer or not during the configure phase. If yes, then
> export a new macro HAVE_NEWER_LIBCAP to be used in /lapi/capability.h.

Yes, this could work.

>
> The following patch has been verified on both rhel6 and rhel8, any comments?
> [I'm not familiar with m4 syntax, just copy from other places]

m4 all looks ugly to me ;-)

>
> diff --git a/include/lapi/capability.h b/include/lapi/capability.h
> index 3c2ee7937..3607179b5 100644
> --- a/include/lapi/capability.h
> +++ b/include/lapi/capability.h
> @@ -10,7 +10,9 @@
>
>  #ifdef HAVE_SYS_CAPABILITY_H
>  # include <sys/capability.h>
> -# undef _LINUX_TYPES_H
> +# ifndef HAVE_NEWER_LIBCAP
> +#  undef _LINUX_TYPES_H
> +# endif
>  #endif

This is so wierd it maybe deserves a comment. Otherwise, this looks good
to me.

>
>  #ifndef CAP_NET_RAW
> diff --git a/m4/ltp-cap.m4 b/m4/ltp-cap.m4
> index 02d3cac8c..8b1546401 100644
> --- a/m4/ltp-cap.m4
> +++ b/m4/ltp-cap.m4
> @@ -14,4 +14,20 @@ if test "x$cap_libs" != x; then
>         AC_DEFINE(HAVE_LIBCAP)
>  fi
>  AC_SUBST(CAP_LIBS,$cap_libs)
> +
> +AH_TEMPLATE(HAVE_NEWER_LIBCAP,
> +[Define to 1 if you have newer libcap-2 installed.])
> +AC_COMPILE_IFELSE([AC_LANG_SOURCE([
> +#include <sys/capability.h>
> +#include <linux/types.h>
> +int main(void) {
> +       __u16 a;
> +       __u32 b;
> +       return 0;
> +}])],[has_newer_libcap="yes"])
> +
> +if test "x$has_newer_libcap" = xyes; then
> +       AC_DEFINE(HAVE_NEWER_LIBCAP)
> +fi
>  ])


-- 
Thank you,
Richard.