Re: [Qemu-devel] [PATCH 14/14] qio/chardev: specify gcontext for TLS handshake

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

On Wed, Feb 28, 2018 at 01:06:33PM +0800, Peter Xu wrote:
> We allow the TLS code to be run with non-default gcontext by providing a
> new qio_channel_tls_handshake_full() API.
> 
> With the new API, we can re-setup the TLS handshake GSource by calling
> it again with the correct gcontext.  Any call to the function will clean
> up existing GSource tasks, and re-setup using the new gcontext.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  chardev/char-socket.c    | 30 +++++++++++++---
>  include/io/channel-tls.h | 22 +++++++++++-
>  io/channel-tls.c         | 91 ++++++++++++++++++++++++++++++++++++++++--------
>  3 files changed, 123 insertions(+), 20 deletions(-)
> 
> diff --git a/chardev/char-socket.c b/chardev/char-socket.c
> index 164a64ff34..406d33c04f 100644
> --- a/chardev/char-socket.c
> +++ b/chardev/char-socket.c
> @@ -72,6 +72,9 @@ typedef struct {
>  
>  static gboolean socket_reconnect_timeout(gpointer opaque);
>  static void tcp_chr_telnet_init(Chardev *chr);
> +static void tcp_chr_tls_handshake_setup(Chardev *chr,
> +                                        QIOChannelTLS *tioc,
> +                                        GMainContext *context);
>  
>  static void tcp_chr_reconn_timer_cancel(SocketChardev *s)
>  {
> @@ -570,6 +573,7 @@ static void tcp_chr_telnet_destroy(SocketChardev *s)
>  static void tcp_chr_update_read_handler(Chardev *chr)
>  {
>      SocketChardev *s = SOCKET_CHARDEV(chr);
> +    QIOChannelTLS *tioc;
>  
>      if (s->listener) {
>          /*
> @@ -589,6 +593,17 @@ static void tcp_chr_update_read_handler(Chardev *chr)
>          qio_task_context_set(s->thread_task, chr->gcontext);
>      }
>  
> +    tioc = (QIOChannelTLS *)object_dynamic_cast(OBJECT(s->ioc),
> +                                                TYPE_QIO_CHANNEL_TLS);
> +    if (tioc) {
> +        /*
> +         * TLS session enabled; reconfigure things up.  Note that, if
> +         * there is existing handshake task, it'll be cleaned up first
> +         * in QIO code.
> +         */
> +        tcp_chr_tls_handshake_setup(chr, tioc, chr->gcontext);
> +    }

This is crazy - we should not be looking at specific implementations of
the channel. If the TLS object needs to use a specific GMainContext we
should make sure that is done right from the start and not try to change
the GMainContext on the fly.

Regards,
Daniel
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