Hi
On Fri, Sep 30, 2022 at 11:49 PM Christian Schoenebeck
<qemu_...@crudebyte.com> wrote:
>
> On Donnerstag, 29. September 2022 18:32:37 CEST Marc-André Lureau wrote:
> > From: Marc-André Lureau <marcandre.lur...@redhat.com>
> >
> > If slirp is not found during compile-time, and not manually disabled,
> > print a friendly error message, as suggested in the "If your networking
> > is failing after updating to the latest git version of QEMU..." thread
> > by various people.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> > ---
> > meson.build | 4 ++++
> > net/net.c | 19 +++++++++++++++++--
> > 2 files changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/meson.build b/meson.build
> > index 8dc661363f..4f69d7d0b4 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -657,6 +657,10 @@ if not get_option('slirp').auto() or have_system
> > endif
> > endif
> >
> > +if get_option('slirp').disabled()
> > + config_host_data.set('CONFIG_SLIRP_DISABLED', true)
> > +endif
> > +
> > vde = not_found
> > if not get_option('vde').auto() or have_system or have_tools
> > vde = cc.find_library('vdeplug', has_headers: ['libvdeplug.h'],
> > diff --git a/net/net.c b/net/net.c
> > index 2db160e063..e6072a5ddd 100644
> > --- a/net/net.c
> > +++ b/net/net.c
> > @@ -990,14 +990,29 @@ static int net_init_nic(const Netdev *netdev, const
> > char *name, return idx;
> > }
> >
> > +#if (defined(CONFIG_SLIRP) || !defined(CONFIG_SLIRP_DISABLED))
> > +static int net_init_user(const Netdev *netdev, const char *name,
> > + NetClientState *peer, Error **errp)
> > +{
> > +#ifdef CONFIG_SLIRP
> > + return net_init_slirp(netdev, name, peer, errp);
> > +#else
> > + error_setg(errp,
> > + "Type 'user' is not a supported netdev backend by this QEMU
> > build " + "because the libslirp development files were not
> > found during build " + "of QEMU.");
> > +#endif
> > + return -1;
> > +}
> > +#endif
>
> I just tried this, but somehow it is not working for me. net_init_user() is
> never called and therefore I don't get the error message. That should be
> working if the user launched QEMU without any networking arg, right?
>
That's because vl.c has:
if (default_net) {
...
#ifdef CONFIG_SLIRP
qemu_opts_parse(net, "user", true, &error_abort);
#endif
Iow, it doesn't try to use slirp by default if it's not found at
compile time. We can eventually change that, but that might break
existing users who don't build with slirp.
Alternatively, it could error out only if slirp was not explicitly
disabled at configure time.
> And still, I would find it better if there was also a clear build-time error
> if there was no libslirp and slirp feature was not explicitly disabled.
That's not the typical way we deal with dependencies, but I can try to
do that as well.
>
> >
> > static int (* const net_client_init_fun[NET_CLIENT_DRIVER__MAX])(
> > const Netdev *netdev,
> > const char *name,
> > NetClientState *peer, Error **errp) = {
> > [NET_CLIENT_DRIVER_NIC] = net_init_nic,
> > -#ifdef CONFIG_SLIRP
> > - [NET_CLIENT_DRIVER_USER] = net_init_slirp,
> > +#if (defined(CONFIG_SLIRP) || !defined(CONFIG_SLIRP_DISABLED))
> > + [NET_CLIENT_DRIVER_USER] = net_init_user,
> > #endif
> > [NET_CLIENT_DRIVER_TAP] = net_init_tap,
> > [NET_CLIENT_DRIVER_SOCKET] = net_init_socket,
>
>
>
>
