Re: [PATCH 1/1] util/getauxval: Porting to FreeBSD getauxval feature

[David CARLIER]

>From 316cbdea0434a523c78d3f18fe7e6697577e4aae Mon Sep 17 00:00:00 2001
From: David Carlier <address@hidden>
Date: Tue, 26 May 2020 08:33:12 +0100
Subject: [PATCH] util/getauxval: Porting to FreeBSD the getauxval feature

FreeBSD has a similar API for auxiliary vector.

Signed-off-by: David Carlier <address@hidden>
---
 configure        | 5 +++++
 util/getauxval.c | 6 ++++++
 2 files changed, 11 insertions(+)

diff --git a/configure b/configure
index 2fc05c4465..2c93867080 100755
--- a/configure
+++ b/configure
@@ -5824,7 +5824,12 @@ getauxval=no
 cat > $TMPC << EOF
 #include <sys/auxv.h>
 int main(void) {
+#if defined(__FreeBSD__)
+  unsigned long a = 0;
+  return elf_aux_info(AT_HWCAP, &a, sizeof(a)) == 0;
+#else
   return getauxval(AT_HWCAP) == 0;
+#endif
 }
 EOF
 if compile_prog "" "" ; then
diff --git a/util/getauxval.c b/util/getauxval.c
index 36afdfb9e6..373ed3899f 100644
--- a/util/getauxval.c
+++ b/util/getauxval.c
@@ -33,7 +33,13 @@

 unsigned long qemu_getauxval(unsigned long key)
 {
+#if defined(__linux__)
     return getauxval(key);
+#elif defined(__FreeBSD__)
+    unsigned long aux = 0;
+    elf_aux_info(key, &aux, sizeof(aux));
+    return aux;
+#endif
 }
 #elif defined(__linux__)
 #include "elf.h"
-- 
2.27.0.rc0

On Tue, 26 May 2020 at 08:21, Thomas Huth <address@hidden> wrote:
>
> On 24/05/2020 14.09, David CARLIER wrote:
> > Hi here porting qemu_getauxval to FreeBSD. Thanks. Regards.
> >
> > From 5be5e56a59631b28ed7b738d251dda252ba9b03e Mon Sep 17 00:00:00 2001
> > From: David Carlier <address@hidden>
> > Date: Sun, 24 May 2020 13:03:32 +0100
> > Subject: [PATCH] util/getauxval: FreeBSD has a similar auxilary vector API
> >
> > Signed-off-by: David Carlier <address@hidden>
> > ---
> >  configure        | 6 ++++++
> >  util/getauxval.c | 6 ++++++
> >  2 files changed, 12 insertions(+)
> >
> > diff --git a/configure b/configure
> > index 2fc05c4465..545fd2364f 100755
> > --- a/configure
> > +++ b/configure
> > @@ -5824,7 +5824,13 @@ getauxval=no
> >  cat > $TMPC << EOF
> >  #include <sys/auxv.h>
> >  int main(void) {
> > +#if defined(__linux__)
> >    return getauxval(AT_HWCAP) == 0;
> > +#elif defined(__FreeBSD__)
> > +  unsigned long a = 0;
> > +  return elf_aux_info(AT_HWCAP, &a, sizeof(a)) == 0;
> > +#endif
> > +  return 1;
> >  }
> >  EOF
> >  if compile_prog "" "" ; then
>
> That configure check looks wrong. On other systems (i.e. non-Linux and
> non-FreeBSD), this code snippet will now compile successfully and thus
> the configure script sets getauxval=yes. I'd suggest you change it this
> way instead:
>
>  int main(void) {
> +#if defined(__FreeBSD__)
> +  unsigned long a = 0;
> +  return elf_aux_info(AT_HWCAP, &a, sizeof(a)) == 0;
> +#else
>    return getauxval(AT_HWCAP) == 0;
> +#endif
>  }
>
> ... so that it still fails to compile by default on other systems.
>
>  Thomas
>