+ return fd;
+}
+
+int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
+ int vnet_hdr_required, int mq_required, Error **errp)
+{
+ int fd = -1;
+
+ /* If the specified tap device already exists just use it. */
+ if (ifname[0] != '\0') {
+ char dname[100];
+ snprintf(dname, sizeof dname, "/dev/%s", ifname);
+ TFR(fd = open(dname, O_RDWR));
+ if (fd < 0 && errno != ENOENT) {
+ error_setg_errno(errp, errno, "could not open %s", dname);
+ return -1;
+ }
+ }
+
+ if (fd < 0) {
+ /* Tap device not specified or does not exist. */
+ if ((fd = tap_open_clone(ifname, ifname_size, errp)) < 0) {
+ return -1;
+ }
+ }
+