Re: [Qemu-devel] [PATCH] slirp: Add explanation for hostfwd parsing failure

[Philippe Mathieu-Daudé]

On 09/08/2017 03:36 PM, Dr. David Alan Gilbert wrote:
> * Philippe Mathieu-Daudé (address@hidden) wrote:
> > On 09/08/2017 01:22 PM, Dr. David Alan Gilbert wrote:
> > > * Philippe Mathieu-Daudé (address@hidden) wrote:
> > > > Hi David,
> > > >
> > > > On 09/08/2017 12:53 PM, Dr. David Alan Gilbert (git) wrote:
> > > > > From: "Dr. David Alan Gilbert" <address@hidden>
> > > > >
> > > > > e.g.
> > > > > ./x86_64-softmmu/qemu-system-x86_64 -nographic -netdev 
> > > > > 'user,id=vnet,hostfwd=:555.0.0.0:0-:22'
> > > > > qemu-system-x86_64: -netdev user,id=vnet,hostfwd=:555.0.0.0:0-:22: Invalid host 
> > > > > forwarding rule ':555.0.0.0:0-:22' (Bad host address)
> > > > >
> > > > > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > > > > ---
> > > > >     net/slirp.c | 13 ++++++++++++-
> > > > >     1 file changed, 12 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/net/slirp.c b/net/slirp.c
> > > > > index 01ed21c006..d87664d42e 100644
> > > > > --- a/net/slirp.c
> > > > > +++ b/net/slirp.c
> > > > > @@ -496,9 +496,11 @@ static int slirp_hostfwd(SlirpState *s, const char 
> > > > > *redir_str,
> > > > >         char buf[256];
> > > > >         int is_udp;
> > > > >         char *end;
> > > > > +    const char *fail_reason = "";
> > > >
> > > > Isn't it better not initialize this? So if one add a new failed syntax case
> > > > the build with abort with -Werror=uninitialized
> > >
> > > I never quite trust compilers to spot it or not-moan even though
> > > every route to failure will have set it.
> >
> > I see, what about:
> >
> > const char *fail_reason = "Unknown reason";
>
> I could, but you're right that I shouldn't miss any, and
> 'Unknown Reason' doesn't tell the user any more than no message.

It's not you I'm worried about ;) but if someone adds a new forward 
layer tomorrow (sctp, udplite, rudp...)