Re: [Qemu-devel] [PATCH v2 2/4] ui/vnc.c: polish vnc_init_func

[Fei Li]

On 09/12/2018 03:57 PM, Fam Zheng wrote:
> On Fri, 09/07 21:39, Fei Li wrote:
> > Add a new Error parameter for vnc_display_init() to handle errors
> > in its caller: vnc_init_func(), just like vnc_display_open() does.
> > And let the call trace propagate the Error.
> >
> > Besides, make vnc_start_worker_thread() return a bool to indicate
> > whether it succeeds instead of returning nothing.
> >
> > Signed-off-by: Fei Li <address@hidden>
> > ---
> >   include/ui/console.h |  2 +-
> >   ui/vnc-jobs.c        |  9 ++++++---
> >   ui/vnc-jobs.h        |  2 +-
> >   ui/vnc.c             | 12 +++++++++---
> >   4 files changed, 17 insertions(+), 8 deletions(-)
> >
> > diff --git a/include/ui/console.h b/include/ui/console.h
> > index fb969caf70..c17803c530 100644
> > --- a/include/ui/console.h
> > +++ b/include/ui/console.h
> > @@ -453,7 +453,7 @@ void qemu_display_early_init(DisplayOptions *opts);
> >   void qemu_display_init(DisplayState *ds, DisplayOptions *opts);
> >   
> >   /* vnc.c */
> > -void vnc_display_init(const char *id);
> > +void vnc_display_init(const char *id, Error **errp);
> >   void vnc_display_open(const char *id, Error **errp);
> >   void vnc_display_add_client(const char *id, int csock, bool skipauth);
> >   int vnc_display_password(const char *id, const char *password);
> > diff --git a/ui/vnc-jobs.c b/ui/vnc-jobs.c
> > index 929391f85d..8807d7217c 100644
> > --- a/ui/vnc-jobs.c
> > +++ b/ui/vnc-jobs.c
> > @@ -331,15 +331,18 @@ static bool vnc_worker_thread_running(void)
> >       return queue; /* Check global queue */
> >   }
> >   
> > -void vnc_start_worker_thread(void)
> > +bool vnc_start_worker_thread(Error **errp)
> >   {
> >       VncJobQueue *q;
> >   
> > -    if (vnc_worker_thread_running())
> > -        return ;
> > +    if (vnc_worker_thread_running()) {
> > +        goto out;
> > +    }
> >   
> >       q = vnc_queue_init();
> >       qemu_thread_create(&q->thread, "vnc_worker", vnc_worker_thread, q,
> >                          QEMU_THREAD_DETACHED);
> >       queue = q; /* Set global queue */
> > +out:
> > +    return true;
> This function always returns true?
Yes, until checking qemu_thread_create()'s return value. Before applying
the checking code, qemu_thread_create still keeps abort() on failure.

Have a nice day, thanks
Fei
> >   }
> > diff --git a/ui/vnc-jobs.h b/ui/vnc-jobs.h
> > index 59f66bcc35..14640593db 100644
> > --- a/ui/vnc-jobs.h
> > +++ b/ui/vnc-jobs.h
> > @@ -37,7 +37,7 @@ void vnc_job_push(VncJob *job);
> >   void vnc_jobs_join(VncState *vs);
> >   
> >   void vnc_jobs_consume_buffer(VncState *vs);
> > -void vnc_start_worker_thread(void);
> > +bool vnc_start_worker_thread(Error **errp);
> >   
> >   /* Locks */
> >   static inline int vnc_trylock_display(VncDisplay *vd)
> > diff --git a/ui/vnc.c b/ui/vnc.c
> > index ccb1335d86..f632635ea4 100644
> > --- a/ui/vnc.c
> > +++ b/ui/vnc.c
> > @@ -3206,7 +3206,7 @@ static const DisplayChangeListenerOps dcl_ops = {
> >       .dpy_cursor_define    = vnc_dpy_cursor_define,
> >   };
> >   
> > -void vnc_display_init(const char *id)
> > +void vnc_display_init(const char *id, Error **errp)
> >   {
> >       VncDisplay *vd;
> >   
> > @@ -3236,7 +3236,9 @@ void vnc_display_init(const char *id)
> >       vd->connections_limit = 32;
> >   
> >       qemu_mutex_init(&vd->mutex);
> > -    vnc_start_worker_thread();
> > +    if (!vnc_start_worker_thread(errp)) {
> > +        return;
> > +    }
> >   
> >       vd->dcl.ops = &dcl_ops;
> >       register_displaychangelistener(&vd->dcl);
> > @@ -4079,7 +4081,11 @@ int vnc_init_func(void *opaque, QemuOpts *opts, Error 
> > **errp)
> >       char *id = (char *)qemu_opts_id(opts);
> >   
> >       assert(id);
> > -    vnc_display_init(id);
> > +    vnc_display_init(id, &local_err);
> > +    if (local_err) {
> > +        error_reportf_err(local_err, "Failed to init VNC server: ");
> > +        exit(1);
> > +    }
> >       vnc_display_open(id, &local_err);
> >       if (local_err != NULL) {
> >           error_reportf_err(local_err, "Failed to start VNC server: ");
> > --
> > 2.13.7
> Fam