Re: [Qemu-devel] [PATCH] char: fix ctrl-a b not working

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/01/2017 12:06, Marc-André Lureau wrote:
> CharDriverState.be should be updated to point to the current
> associated backend.
> 
> Fix the regression introduced in the "mux" chardev from commit
> a4afa548fc6dd9842ed86639b4d37d4d1c4ad480.
> 
> https://bugs.launchpad.net/bugs/1654137

Queued.

However, can you also simplify mux_chr_accept_input, mux_chr_can_read
and mux_chr_read to use d->be directly, with this change?

Thanks,

Paolo

> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  qemu-char.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)
> 
> diff --git a/qemu-char.c b/qemu-char.c
> index 2c9940cea4..676944a765 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -499,7 +499,7 @@ void qemu_chr_fe_printf(CharBackend *be, const char *fmt, ...)
>  
>  static void remove_fd_in_watch(CharDriverState *chr);
>  static void mux_chr_set_handlers(CharDriverState *chr, GMainContext *context);
> -static void mux_set_focus(MuxDriver *d, int focus);
> +static void mux_set_focus(CharDriverState *chr, int focus);
>  
>  static int null_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
>  {
> @@ -666,7 +666,7 @@ static int mux_proc_byte(CharDriverState *chr, MuxDriver *d, int ch)
>          case 'c':
>              assert(d->mux_cnt > 0); /* handler registered with first fe */
>              /* Switch to the next registered device */
> -            mux_set_focus(d, (d->focus + 1) % d->mux_cnt);
> +            mux_set_focus(chr, (d->focus + 1) % d->mux_cnt);
>              break;
>          case 't':
>              d->timestamps = !d->timestamps;
> @@ -826,8 +826,10 @@ static void mux_chr_set_handlers(CharDriverState *chr, GMainContext *context)
>                               context, true);
>  }
>  
> -static void mux_set_focus(MuxDriver *d, int focus)
> +static void mux_set_focus(CharDriverState *chr, int focus)
>  {
> +    MuxDriver *d = chr->opaque;
> +
>      assert(focus >= 0);
>      assert(focus < d->mux_cnt);
>  
> @@ -836,6 +838,7 @@ static void mux_set_focus(MuxDriver *d, int focus)
>      }
>  
>      d->focus = focus;
> +    chr->be = d->backends[focus];
>      mux_chr_send_event(d, d->focus, CHR_EVENT_MUX_IN);
>  }
>  
> @@ -935,7 +938,9 @@ void qemu_chr_fe_deinit(CharBackend *b)
>  
>      if (b->chr) {
>          qemu_chr_fe_set_handlers(b, NULL, NULL, NULL, NULL, NULL, true);
> -        b->chr->be = NULL;
> +        if (b->chr->be == b) {
> +            b->chr->be = NULL;
> +        }
>          if (b->chr->is_mux) {
>              MuxDriver *d = b->chr->opaque;
>              d->backends[b->tag] = NULL;
> @@ -999,7 +1004,7 @@ void qemu_chr_fe_take_focus(CharBackend *b)
>      }
>  
>      if (b->chr->is_mux) {
> -        mux_set_focus(b->chr->opaque, b->tag);
> +        mux_set_focus(b->chr, b->tag);
>      }
>  }
>  
>