Re: [Qemu-devel] [PATCH v2 1/2] vl: don't use RUN_STATE_PRECONFIG as initial state

[Eduardo Habkost <ehabkost@redhat.com>]

On Mon, Jun 04, 2018 at 04:21:47PM +0200, Michal Privoznik wrote:
[...]
> > @@ -3572,7 +3570,12 @@ int main(int argc, char **argv, char **envp)
> >                  }
> >                  break;
> >              case QEMU_OPTION_preconfig:
> > -                preconfig_exit_requested = false;
> > +                if (!runstate_check(RUN_STATE_NONE)) {
> > +                    error_report("'--preconfig' and '--incoming' options are "
> > +                                 "mutually exclusive");
> > +                    exit(EXIT_FAILURE);
> > +                }
> > +                runstate_set(RUN_STATE_PRECONFIG);
> 
> Specifying --preconfig twice on the command line now fails with a very
> cryptic message (there's no --incoming).
> 
> >                  break;
> >              case QEMU_OPTION_enable_kvm:
> >                  olist = qemu_find_opts("machine");
> > @@ -3768,9 +3771,12 @@ int main(int argc, char **argv, char **envp)
> >                  }
> >                  break;
> >              case QEMU_OPTION_incoming:
> > -                if (!incoming) {
> > -                    runstate_set(RUN_STATE_INMIGRATE);
> > +                if (!runstate_check(RUN_STATE_NONE)) {
> > +                    error_report("'--preconfig' and '--incoming' options are "
> > +                                 "mutually exclusive");
> > +                    exit(EXIT_FAILURE);
> >                  }
> > +                runstate_set(RUN_STATE_INMIGRATE);
> 
> Same here. Specifying --incoming twice fails with cryptic message. But
> one can argue that specifying --incoming twice is wrong anyway.
> 

Initially I was going to suggest simply not changing runstate
during option parsing to avoid this kind of problem, but maybe
this would be a nice way to implement the command-line parsing
rules:


    case QEMU_OPTION_preconfig:
        /*
         * A INCOMING -> PRECONFIG transition would call:
         *   error_setg("--preconfig and --incoming options are mutually exclusive");
         */
        try_runstate_set(RUN_STATE_PRECONFIG, &error_fatal);
        break;
    case QEMU_OPTION_incoming:
        /*
         * A PRECONFIG -> INCOMING transition would also call:
         *   error_setg("--preconfig and --incoming options are mutually exclusive");
         *
         * Maybe a INCOMING -> INCOMING transition could
         * result in:
         *   error_setg("--incoming can't be specified twice");
         */
        try_runstate_set(RUN_STATE_INMIGRATE, &error_fatal);
        break;


> >                  incoming = optarg;
> >                  break;
> >              case QEMU_OPTION_only_migratable:
> 
> Michal
> 

-- 
Eduardo