Re: [Qemu-devel] [PATCH v3 8/9] qga: process_event() simplification

[Michael Roth]

Quoting Marc-André Lureau (2018-08-28 06:56:51)
> Hi
> On Tue, Aug 28, 2018 at 2:05 AM Michael Roth <address@hidden> wrote:
> >
> > Quoting Marc-André Lureau (2018-08-25 08:57:23)
> > > Simplify the code around qmp_dispatch():
> > > - rely on qmp_dispatch/check_obj() for message checking
> > > - have a single send_response() point
> > > - constify send_response() argument
> > >
> > > It changes a couple of error messages:
> > >
> > > * When @req isn't a dictionary, from
> > >     Invalid JSON syntax
> > >   to
> > >     QMP input must be a JSON object
> > >
> > > * When @req lacks member "execute", from
> > >     this feature or command is not currently supported
> > >   to
> > >     QMP input lacks member 'execute'
> > >
> > > CC: Michael Roth <address@hidden>
> > > Signed-off-by: Marc-André Lureau <address@hidden>
> > > ---
> > >  qga/main.c | 47 +++++++++--------------------------------------
> > >  1 file changed, 9 insertions(+), 38 deletions(-)
> > >
> > > diff --git a/qga/main.c b/qga/main.c
> > > index 6d70242d05..f0ec035996 100644
> > > --- a/qga/main.c
> > > +++ b/qga/main.c
> > > @@ -544,15 +544,15 @@ fail:
> > >  #endif
> > >  }
> > >
> > > -static int send_response(GAState *s, QDict *payload)
> > > +static int send_response(GAState *s, const QDict *rsp)
> > >  {
> > >      const char *buf;
> > >      QString *payload_qstr, *response_qstr;
> > >      GIOStatus status;
> > >
> > > -    g_assert(payload && s->channel);
> > > +    g_assert(rsp && s->channel);
> > >
> > > -    payload_qstr = qobject_to_json(QOBJECT(payload));
> > > +    payload_qstr = qobject_to_json(QOBJECT(rsp));
> > >      if (!payload_qstr) {
> > >          return -EINVAL;
> > >      }
> > > @@ -578,53 +578,24 @@ static int send_response(GAState *s, QDict *payload)
> > >      return 0;
> > >  }
> > >
> > > -static void process_command(GAState *s, QDict *req)
> > > -{
> > > -    QDict *rsp;
> > > -    int ret;
> > > -
> > > -    g_assert(req);
> > > -    g_debug("processing command");
> > > -    rsp = qmp_dispatch(&ga_commands, QOBJECT(req), false);
> > > -    if (rsp) {
> > > -        ret = send_response(s, rsp);
> > > -        if (ret < 0) {
> > > -            g_warning("error sending response: %s", strerror(-ret));
> > > -        }
> > > -        qobject_unref(rsp);
> > > -    }
> >
> > We used to check here for the success-response=false scenario (e.g.
> > guest-shutdown qga command). Now we pass the result of qmp_dispatch()
> > directly to send_response(), which looks like that might cause an
> > assertion now. Do we need to add handling for this?
> 
> Good catch! fixing it:
> 
> end:
>     if (rsp) {
>         ret = send_response(s, rsp);
>         if (ret < 0) {
>             g_warning("error sending error response: %s", strerror(-ret));
>         }
>         qobject_unref(rsp);
>     }
> 
> ack, with that?

Looks good! With that:

Reviewed-by: Michael Roth <address@hidden>

> 
> > > -}
> > > -
> > >  /* handle requests/control events coming in over the channel */
> > >  static void process_event(void *opaque, QObject *obj, Error *err)
> > >  {
> > >      GAState *s = opaque;
> > > -    QDict *req, *rsp;
> > > +    QDict *rsp;
> > >      int ret;
> > >
> > >      g_debug("process_event: called");
> > >      assert(!obj != !err);
> > >      if (err) {
> > > -        goto err;
> > > -    }
> > > -    req = qobject_to(QDict, obj);
> > > -    if (!req) {
> > > -        error_setg(&err, "Input must be a JSON object");
> > > -        goto err;
> > > -    }
> > > -    if (!qdict_haskey(req, "execute")) {
> > > -        g_warning("unrecognized payload format");
> > > -        error_setg(&err, QERR_UNSUPPORTED);
> > > -        goto err;
> > > +        rsp = qmp_error_response(err);
> > > +        goto end;
> > >      }
> > >
> > > -    process_command(s, req);
> > > -    qobject_unref(obj);
> > > -    return;
> > > +    g_debug("processing command");
> > > +    rsp = qmp_dispatch(&ga_commands, obj, false);
> > >
> > > -err:
> > > -    g_warning("failed to parse event: %s", error_get_pretty(err));
> > > -    rsp = qmp_error_response(err);
> > > +end:
> > >      ret = send_response(s, rsp);
> > >      if (ret < 0) {
> > >          g_warning("error sending error response: %s", strerror(-ret));
> > > --
> > > 2.18.0.547.g1d89318c48
> > >
> >
> 
> 
> -- 
> Marc-André Lureau
>