[PATCH] support: Link links-dso-program-c against libgcc_s

[Sam James]

Florian Weimer <fweimer@redhat.com> writes:

> If C++ support is not available, links-dso-program-c is used
> instead of the C++ version.  The C version was not linked against
> libgcc_s, which meant that thread cancellation and the backtrace
> function did not work in containers tests in that situation.

Reviewed-by: Sam James <sam@gentoo.org>

>
> ---
>  support/Makefile              |  2 ++
>  support/links-dso-program-c.c | 20 ++++++++++++++++++++
>  2 files changed, 22 insertions(+)
>
> diff --git a/support/Makefile b/support/Makefile
> index 59a9974539..0c670555ae 100644
> --- a/support/Makefile
> +++ b/support/Makefile
> @@ -281,6 +281,8 @@ CFLAGS-temp_file.c += -D_FILE_OFFSET_BITS=64 -D_TIME_BITS=64
>  
>  ifeq (,$(CXX))
>  LINKS_DSO_PROGRAM = links-dso-program-c
> +CFLAGS-links-dso-program-c.c += -fexceptions
> +LDLIBS-links-dso-program-c = -lgcc -lgcc_s $(libunwind)
>  else
>  LINKS_DSO_PROGRAM = links-dso-program
>  LDLIBS-links-dso-program = -lstdc++ -lgcc -lgcc_s $(libunwind)
> diff --git a/support/links-dso-program-c.c b/support/links-dso-program-c.c
> index 5fcbab2c17..efe65b4b19 100644
> --- a/support/links-dso-program-c.c
> +++ b/support/links-dso-program-c.c
> @@ -1,4 +1,5 @@
>  #include <stdio.h>
> +#include <dlfcn.h>
>  
>  /* makedb needs selinux dso's.  */
>  #ifdef HAVE_SELINUX
> @@ -13,6 +14,20 @@
>     such dependencies.
>  */
>  
> +/* Use attribute cleanup to force linking against libgcc_s.  */
> +static void
> +cleanup_function (int *ignored)
> +{
> +  puts ("cleanup performed");
> +}
> +
> +void
> +invoke_callback (void (*callback) (int *))
> +{
> +  __attribute__ ((cleanup (cleanup_function))) int i = 0;
> +  callback (&i);
> +}
> +
>  int
>  main (int argc, char **argv)
>  {
> @@ -22,5 +37,10 @@ main (int argc, char **argv)
>    /* This exists to force libselinux.so to be required.  */
>    printf ("selinux %d\n", is_selinux_enabled ());
>  #endif
> +  /* Prevent invoke_callback from being optimized away.  */
> +  {
> +    Dl_info dli;
> +    dladdr (invoke_callback, &dli);
> +  }
>    return 0;
>  }
>
> base-commit: 090dfa40a5e46f7c0e4d6e8369bcbbd51267625f