[PULL,47/91] libvhost-user: set msg.msg_control to NULL when it is empty

Commit Message

Michael S. Tsirkin July 2, 2024, 2:09 p.m. UTC

From: Stefano Garzarella <[e-mail]>

On some OS (e.g. macOS) sendmsg() returns -1 (errno EINVAL) if
the `struct msghdr` has the field `msg_controllen` set to 0, but
`msg_control` is not NULL.

Reviewed-by: Eric Blake <[e-mail]>
Reviewed-by: David Hildenbrand <[e-mail]>
Reviewed-by: Philippe Mathieu-Daudé <[e-mail]>
Tested-by: Philippe Mathieu-Daudé <[e-mail]>
Acked-by: Stefan Hajnoczi <[e-mail]>
Signed-off-by: Stefano Garzarella <[e-mail]>
Message-Id: <[e-mail]>
Reviewed-by: Michael S. Tsirkin <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
---
 subprojects/libvhost-user/libvhost-user.c | 1 +
 1 file changed, 1 insertion(+)

Patch

diff --git a/subprojects/libvhost-user/libvhost-user.c b/subprojects/libvhost-user/libvhost-user.c
index 8adb277d54..53bf1adda6 100644
--- a/subprojects/libvhost-user/libvhost-user.c
+++ b/subprojects/libvhost-user/libvhost-user.c
@@ -632,6 +632,7 @@  vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
         memcpy(CMSG_DATA(cmsg), vmsg->fds, fdsize);
     } else {
         msg.msg_controllen = 0;
+        msg.msg_control = NULL;
     }
 
     do {