Re: [PATCH v2 05/11] chardev: mark explicitly first argument as poisoned

["Daniel P. Berrangé" <berrange@redhat.com>]

On Thu, Aug 05, 2021 at 02:39:28PM +0400, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Aug 5, 2021 at 2:37 PM Daniel P. Berrangé <berrange@redhat.com>
> wrote:
> 
> > On Wed, Aug 04, 2021 at 07:48:42PM +0400, marcandre.lureau@redhat.com
> > wrote:
> > > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> > >
> > > Since commit 9894dc0cdcc397ee5b26370bc53da6d360a363c2 "char: convert
> > > from GIOChannel to QIOChannel", the first argument to the watch callback
> > > can actually be a QIOChannel, which is not a GIOChannel (but a QEMU
> > > Object).
> > >
> > > Even though we never used that pointer, change the callback type to warn
> > > the users. Possibly a better fix later, we may want to store the
> > > callback and call it from intermediary functions.
> > >
> > > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > > ---
> > >  include/chardev/char-fe.h | 8 +++++++-
> > >  chardev/char-fe.c         | 2 +-
> > >  hw/char/cadence_uart.c    | 2 +-
> > >  hw/char/cmsdk-apb-uart.c  | 2 +-
> > >  hw/char/ibex_uart.c       | 2 +-
> > >  hw/char/nrf51_uart.c      | 2 +-
> > >  hw/char/serial.c          | 2 +-
> > >  hw/char/virtio-console.c  | 2 +-
> > >  hw/usb/redirect.c         | 2 +-
> > >  hw/virtio/vhost-user.c    | 2 +-
> > >  monitor/monitor.c         | 2 +-
> > >  net/vhost-user.c          | 4 ++--
> > >  12 files changed, 19 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/include/chardev/char-fe.h b/include/chardev/char-fe.h
> > > index a553843364..867ef1b3b2 100644
> > > --- a/include/chardev/char-fe.h
> > > +++ b/include/chardev/char-fe.h
> > > @@ -174,6 +174,9 @@ void qemu_chr_fe_set_open(CharBackend *be, int
> > fe_open);
> > >  void qemu_chr_fe_printf(CharBackend *be, const char *fmt, ...)
> > >      GCC_FMT_ATTR(2, 3);
> > >
> > > +
> > > +typedef gboolean (*FEWatchFunc)(void *do_not_use, GIOCondition
> > condition, void *data);
> > > +
> > >  /**
> > >   * qemu_chr_fe_add_watch:
> > >   * @cond: the condition to poll for
> > > @@ -188,10 +191,13 @@ void qemu_chr_fe_printf(CharBackend *be, const
> > char *fmt, ...)
> > >   * Note that you are responsible to update the front-end sources if
> > >   * you are switching the main context with qemu_chr_fe_set_handlers().
> > >   *
> > > + * Warning: DO NOT use the first callback argument (it may be either
> > > + * a GIOChannel or a QIOChannel, depending on the underlying chardev)
> > > + *
> > >   * Returns: the source tag
> > >   */
> > >  guint qemu_chr_fe_add_watch(CharBackend *be, GIOCondition cond,
> > > -                            GIOFunc func, void *user_data);
> > > +                            FEWatchFunc func, void *user_data);
> > >
> > >  /**
> > >   * qemu_chr_fe_write:
> > > diff --git a/chardev/char-fe.c b/chardev/char-fe.c
> > > index 474715c5a9..7789f7be9c 100644
> > > --- a/chardev/char-fe.c
> > > +++ b/chardev/char-fe.c
> > > @@ -354,7 +354,7 @@ void qemu_chr_fe_set_open(CharBackend *be, int
> > fe_open)
> > >  }
> > >
> > >  guint qemu_chr_fe_add_watch(CharBackend *be, GIOCondition cond,
> > > -                            GIOFunc func, void *user_data)
> > > +                            FEWatchFunc func, void *user_data)
> > >  {
> > >      Chardev *s = be->chr;
> > >      GSource *src;
> > > diff --git a/hw/char/cadence_uart.c b/hw/char/cadence_uart.c
> > > index ceb677bc5a..8ee6f74b8c 100644
> > > --- a/hw/char/cadence_uart.c
> > > +++ b/hw/char/cadence_uart.c
> > > @@ -288,7 +288,7 @@ static void uart_write_rx_fifo(void *opaque, const
> > uint8_t *buf, int size)
> > >      uart_update_status(s);
> > >  }
> > >
> > > -static gboolean cadence_uart_xmit(GIOChannel *chan, GIOCondition cond,
> > > +static gboolean cadence_uart_xmit(GIOChannel *do_not_use, GIOCondition
> > cond,
> > >                                    void *opaque)
> >
> > Why is this (and the next 3) left as GIOCondition, when you change others
> > later on to be void ?
> >
> 
> Good catch. It's a leftover. It is fixed in my branch
> https://gitlab.com/marcandre.lureau/qemu/-/tree/chardev

Ok, with that

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>



Regards,
Daniel
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