[PATCH 26/33] io/channel-socket: introduce qio_channel_socket_keep_nonblock()

[Vladimir Sementsov-Ogievskiy]

Add a possibility to keep socket non-block status when passing
through qio channel. We need this to support migration of open
fds through migration channel.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
 include/io/channel-socket.h |  3 +++
 io/channel-socket.c         | 16 ++++++++++++----
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/include/io/channel-socket.h b/include/io/channel-socket.h
index a88cf8b3a9..0a4327d745 100644
--- a/include/io/channel-socket.h
+++ b/include/io/channel-socket.h
@@ -49,6 +49,7 @@ struct QIOChannelSocket {
     socklen_t remoteAddrLen;
     ssize_t zero_copy_queued;
     ssize_t zero_copy_sent;
+    bool keep_nonblock;
 };
 
 
@@ -275,4 +276,6 @@ int qio_channel_socket_set_send_buffer(QIOChannelSocket 
*ioc,
                                        size_t size,
                                        Error **errp);
 
+void qio_channel_socket_keep_nonblock(QIOChannel *ioc);
+
 #endif /* QIO_CHANNEL_SOCKET_H */
diff --git a/io/channel-socket.c b/io/channel-socket.c
index 3b7ca924ff..cd93d7f180 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -462,9 +462,16 @@ static void qio_channel_socket_finalize(Object *obj)
 }
 
 
+void qio_channel_socket_keep_nonblock(QIOChannel *ioc)
+{
+    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc);
+    sioc->keep_nonblock = true;
+}
+
+
 #ifndef WIN32
 static void qio_channel_socket_copy_fds(struct msghdr *msg,
-                                        int **fds, size_t *nfds)
+                                        int **fds, size_t *nfds, bool 
set_block)
 {
     struct cmsghdr *cmsg;
 
@@ -497,8 +504,9 @@ static void qio_channel_socket_copy_fds(struct msghdr *msg,
                 continue;
             }
 
-            /* O_NONBLOCK is preserved across SCM_RIGHTS so reset it */
-            qemu_socket_set_block(fd);
+            if (set_block) {
+                qemu_socket_set_block(fd);
+            }
 
 #ifndef MSG_CMSG_CLOEXEC
             qemu_set_cloexec(fd);
@@ -556,7 +564,7 @@ static ssize_t qio_channel_socket_readv(QIOChannel *ioc,
     }
 
     if (fds && nfds) {
-        qio_channel_socket_copy_fds(&msg, fds, nfds);
+        qio_channel_socket_copy_fds(&msg, fds, nfds, !sioc->keep_nonblock);
     }
 
     return ret;
-- 
2.48.1