[PATCH for-9.1 v2 04/11] vhost-user-server: don't abort if we can't set fd non-blocking

[Stefano Garzarella]

In vhost-user-server we set all fd received from the other peer
in non-blocking mode. For some of them (e.g. memfd, shm_open, etc.)
if we fail, it's not really a problem, because we don't use these
fd with blocking operations, but only to map memory.

In these cases a failure is not bad, so let's just report a warning
instead of panicking if we fail to set some fd in non-blocking mode.

This for example occurs in macOS where setting shm_open() fd
non-blocking is failing (errno: 25).

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 util/vhost-user-server.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/util/vhost-user-server.c b/util/vhost-user-server.c
index 3bfb1ad3ec..064999f0b7 100644
--- a/util/vhost-user-server.c
+++ b/util/vhost-user-server.c
@@ -66,7 +66,11 @@ static void vmsg_unblock_fds(VhostUserMsg *vmsg)
 {
     int i;
     for (i = 0; i < vmsg->fd_num; i++) {
-        qemu_socket_set_nonblock(vmsg->fds[i]);
+        int ret = qemu_socket_try_set_nonblock(vmsg->fds[i]);
+        if (ret) {
+            warn_report("Failed to set fd %d nonblock for request %d: %s",
+                        vmsg->fds[i], vmsg->request, strerror(-ret));
+        }
     }
 }
 
-- 
2.44.0