[CRIU] [PATCH 06/12] unix: Fixup queuer of promiscuous DGRAM receivers

[Kirill Tkhai]

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.

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 d06e2a4..3daa1d2 100644
--- a/criu/sk-unix.c
+++ b/criu/sk-unix.c
@@ -1372,6 +1372,26 @@ 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;
@@ -1393,7 +1413,7 @@ 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;
@@ -1402,6 +1422,10 @@ 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