Re: [Xen-devel] [PATCH] don't require ebtables in the host kernel

[Avi Kivity <avi@xxxxxxxxxxxx>]

Ewan Mellor wrote:

> > --- xen/tools/examples/network-bridge   (revision 991)
> > +++ xen/tools/examples/network-bridge   (revision 992)
> > @@ -158,9 +158,9 @@
> >
> >    # Don't create the bridge if it already exists.
> >    if ! brctl show | grep -q ${bridge} ; then
> > -       sysctl -w "net.bridge.bridge-nf-call-arptables=0"
> > -       sysctl -w "net.bridge.bridge-nf-call-ip6tables=0"
> > -       sysctl -w "net.bridge.bridge-nf-call-iptables=0"
> > +       ! sysctl -w "net.bridge.bridge-nf-call-arptables=0"
> > +       ! sysctl -w "net.bridge.bridge-nf-call-ip6tables=0"
> > +       ! sysctl -w "net.bridge.bridge-nf-call-iptables=0"
> >         brctl addbr ${bridge}
> >         brctl stp ${bridge} off
> >         brctl setfd ${bridge} 0
> >    
> Where did this network-bridge script come from?  The stock Xen-3.0
> network-bridge doesn't have these sysctl lines in the first place.
>  
It comes from FC5. Sorry, should have checked the pristine Xen sources. 
Sorry about the noise.
> Furthermore, using ! doesn't ignore the return value -- it inverts it.  I'd be
> surprised if this works in systems that _do_ have ebtables.
>  
No, ! on the beginning of a command tells bash to ignore the exit code:

   `-e'
         Exit immediately if a simple command (*note Simple
         Commands::) exits with a non-zero status, unless the command
         that fails is part of the command list immediately following
         a `while' or `until' keyword, part of the test in an `if'
         statement, part of a `&&' or `||' list, or if the command's
         return status is being inverted using `!'.  A trap on `ERR',
         if set, is executed before the shell exits.

'sysctl -ew' would have been better though.

--
error compiling committee.c: too many arguments to function


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