On Wed, Aug 13, 2025 at 07:48:47PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> 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;
If this is needed, then it should be done by defining another flag
constant to be passed to qio_channel_read*, not via a new API
QIO_CHANNEL_READ_FLAG_FD_PRESERVE_NONBLOCKING
With regards,
Daniel
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