
I'm getting: could not configure /dev/net/tun (tap%d): Operation not permitted When the ioctl() fails, ifr.ifr_name will most likely not be overwritten. So we better only use it when ifname contains a string. Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>