[CRIU] [PATCH v2 09/15] unix: Fixup queuer of promiscuous DGRAM receivers

[Pavel Emelyanov]

On 05/27/2016 04:07 PM, Kirill Tkhai wrote:
> If packets in a receive queue of a sockets have more than 1 sender,
> we should not name "queuer" one of them. Otherwise, we restore them
> with the only msg_name.

With which?

> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
> ---
>  criu/sk-unix.c |   26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/criu/sk-unix.c b/criu/sk-unix.c
> index 076100c..cf589b8 100644
> --- a/criu/sk-unix.c
> +++ b/criu/sk-unix.c
> @@ -1386,6 +1386,26 @@ struct collect_image_info unix_sk_cinfo = {
>  	.flags = COLLECT_SHARED,
>  };
>  
> +static u32 sk_queuer(struct unix_sk_info *sk, struct unix_sk_info *maybe_queuer)
> +{
> +	if (maybe_queuer->peer != sk) {
> +		pr_err("sk is not peer of passed queuer\n");
> +		return 0;
> +	}
> +
> +	/* Nothing is restored if queue is empty. Set fake queuer for that. */
> +	if (sk->ue->type != SOCK_DGRAM || (sk->ue->uflags & USK_EMPTY_Q))
> +		return maybe_queuer->ue->ino;
> +
> +	if ((sk->ue->uflags & USK_NONAME_SND) && maybe_queuer->ue->name.len == 0)
> +		return maybe_queuer->ue->ino;
> +
> +	if (sk->ue->has_sender_ino && sk->ue->sender_ino == maybe_queuer->ue->ino)
> +		return maybe_queuer->ue->ino;
> +
> +	return 0;
> +}
> +
>  static int resolve_unix_peers(void *unused)
>  {
>  	struct unix_sk_info *ui, *peer;
> @@ -1407,7 +1427,7 @@ static int resolve_unix_peers(void *unused)
>  
>  		ui->peer = peer;
>  		if (!peer->queuer)
> -			peer->queuer = ui->ue->ino;
> +			peer->queuer = sk_queuer(peer, ui);
>  		if (ui == peer)
>  			/* socket connected to self %) */
>  			continue;
> @@ -1416,6 +1436,10 @@ static int resolve_unix_peers(void *unused)
>  
>  		/* socketpair or interconnected sockets */
>  		peer->peer = ui;
> +		ui->queuer = sk_queuer(ui, peer);
> +
> +		if (!peer->queuer || !ui->queuer)
> +			continue;
>  
>  		/*
>  		 * Select who will restore the pair. Check is identical to
> 
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