Re: [PATCH 1/2] meson: Check for seccomp/cap-ng libraries if virtiofsd is enabled

[Peter Maydell]

On Wed, 28 Apr 2021 at 15:55, Philippe Mathieu-Daudé <philmd@redhat.com> wrote:

(cc'ing Paolo for a meson.build question below...)

> When not explicitly select a sysemu target and building virtiofsd,
> the seccomp/cap-ng libraries are not resolved, leading to this error:
>
>   $ configure --target-list=i386-linux-user --disable-tools --enable-virtiofsd
>   tools/meson.build:12:6: ERROR: Problem encountered: virtiofsd requires 
> libcap-ng-devel and seccomp-devel
>
> Fix by checking the seccomp/cap-ng libraries if virtiofsd is built.
>
> Reported-by: Mahmoud Mandour <ma.mandourr@gmail.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  meson.build | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/meson.build b/meson.build
> index c6f4b0cf5e8..b466b418fed 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -393,14 +393,14 @@
>  endif
>
>  seccomp = not_found
> -if not get_option('seccomp').auto() or have_system or have_tools
> +if not get_option('seccomp').auto() or have_system or have_tools or not 
> get_option('virtiofsd').auto()
>    seccomp = dependency('libseccomp', version: '>=2.3.0',
>                         required: get_option('seccomp'),
>                         method: 'pkg-config', kwargs: static_kwargs)
>  endif
>
>  libcap_ng = not_found
> -if not get_option('cap_ng').auto() or have_system or have_tools
> +if not get_option('cap_ng').auto() or have_system or have_tools or not 
> get_option('virtiofsd').auto()
>    libcap_ng = cc.find_library('cap-ng', has_headers: ['cap-ng.h'],
>                                required: get_option('cap_ng'),
>                                kwargs: static_kwargs)

Now we have "virtiofsd requires cap-ng and seccomp" recorded in three
places in different meson.build files:
 * here, if this patch goes in
 * in tools/meson.build, in its logic for setting have_virtiofsd
   (I generously do not count the "decide which error message to print"
   logic in that file as a separate item in this list...)
 * in tools/virtiofsd/meson.build, where the executable('virtiofsd', ...)
   lists them in its dependencies: setting

Is there some way to avoid this duplication?

thanks
-- PMM