xen: call qemu_set_cloexec instead of fcntl

Use the common utility function, which contains checks on return values
and first calls F_GETFD as recommended by POSIX.1-2001, instead of
manually calling fcntl.

CID: 1374831

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
CC: anthony.perard@citrix.com
CC: groug@kaod.org
CC: aneesh.kumar@linux.vnet.ibm.com
CC: Eric Blake <eblake@redhat.com>

hw/9pfs/xen-9p-backend.c

@@ -380,7 +380,7 @@ static int xen_9pfs_connect(struct XenDevice *xendev)
         if (xen_9pdev->rings[i].evtchndev == NULL) {
             goto out;
         }
-        fcntl(xenevtchn_fd(xen_9pdev->rings[i].evtchndev), F_SETFD, FD_CLOEXEC);
+        qemu_set_cloexec(xenevtchn_fd(xen_9pdev->rings[i].evtchndev));
         xen_9pdev->rings[i].local_port = xenevtchn_bind_interdomain
                                             (xen_9pdev->rings[i].evtchndev,
                                              xendev->dom,

hw/xen/xen_backend.c

@@ -147,7 +147,7 @@ static struct XenDevice *xen_be_get_xendev(const char *type, int dom, int dev,
         qdev_unplug(DEVICE(xendev), NULL);
         return NULL;
     }
-    fcntl(xenevtchn_fd(xendev->evtchndev), F_SETFD, FD_CLOEXEC);
+    qemu_set_cloexec(xenevtchn_fd(xendev->evtchndev));
 
     if (ops->flags & DEVOPS_FLAG_NEED_GNTDEV) {
         xendev->gnttabdev = xengnttab_open(NULL, 0);