[CRIU] [PATCH 18/19] files: Allow to send unix sockets over unix sockets

[Kirill Tkhai]

Everything is ready. Message queue restores are in
the second stage of open for all types of unix sockets.
We just need to make scm wait before restore_unix_queue()
and allow to dump such scm context.

Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>
---
 criu/sk-queue.c |    9 ---------
 criu/sk-unix.c  |   12 ++++++------
 2 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/criu/sk-queue.c b/criu/sk-queue.c
index 7f5aa1d58..b5fb6b76c 100644
--- a/criu/sk-queue.c
+++ b/criu/sk-queue.c
@@ -100,15 +100,6 @@ static int dump_scm_rights(struct cmsghdr *ch, SkPacketEntry *pe)
 
 		if (dump_my_file(fds[i], &scme->rights[i], &ftyp))
 			return -1;
-
-		/*
-		 * Unix sent over Unix are tricky and not supported
-		 * for now. (XXX -- todo).
-		 */
-		if (ftyp == FD_TYPES__UNIXSK) {
-			pr_err("Can't dump send %d (unix/epoll) fd\n", ftyp);
-			return -1;
-		}
 	}
 
 	i = pe->n_scm++;
diff --git a/criu/sk-unix.c b/criu/sk-unix.c
index 10ef327cc..6bc41773e 100644
--- a/criu/sk-unix.c
+++ b/criu/sk-unix.c
@@ -1123,6 +1123,9 @@ static int post_open_standalone(struct file_desc *d, int fd)
 	BUG_ON((ui->flags & (USK_PAIR_MASTER | USK_PAIR_SLAVE)) ||
 			(ui->ue->uflags & (USK_CALLBACK | USK_INHERIT)));
 
+	if (chk_restored_scms(ui))
+		return 1;
+
 	peer = ui->peer;
 	if (!peer || ui->is_connected)
 		goto restore_sk_common;
@@ -1292,6 +1295,9 @@ static int post_open_interconnected_master(struct unix_sk_info *ui)
 	fle_peer = file_master(&peer->d);
 	BUG_ON(fle->task != fle_peer->task); /* See interconnected_pair() */
 
+	if (chk_restored_scms(ui) || chk_restored_scms(peer))
+		return 0;
+
 	if (restore_unix_queue(fle->fe->fd, peer))
 		return -1;
 
@@ -1563,12 +1569,6 @@ static int open_unix_sk(struct file_desc *d, int *new_fd)
 
 	ui = container_of(d, struct unix_sk_info, d);
 
-	/* FIXME -- only queue restore may be postponed */
-	if (chk_restored_scms(ui)) {
-		pr_info("scm: Wait for tgt to restore\n");
-		return 1;
-	}
-
 	if (inherited_fd(d, new_fd)) {
 		ui->ue->uflags |= USK_INHERIT;
 		ret = *new_fd >= 0 ? 0 : -1;