udev-event.c: rename interface to <src>-<dest>, if <dest> taken

e.g. if eth0 should be eth3 and eth3 is waiting to be renamed,
eth0 was renamed to eth0_rename. The kernel would take eth0 as the name
for a new interface and this new eth0 could also become eth0_rename, if
the target name is also taken. To prevent this name clash, the
interfaces are now renamed to <src>-<dest> and the rename is logged.

diff --git a/udev/udev-event.c b/udev/udev-event.c
index 7591d5e314b3693fa55d903dbbf6582aef843147..7785ad892c308a1b07bee1d8ddab06576e505479 100644 (file)
--- a/udev/udev-event.c
+++ b/udev/udev-event.c
@@ -465,6 +465,7 @@ static int rename_netif(struct udev_event *event)
        int sk;
        struct ifreq ifr;
        int err;
+       char *newdup;
 
        info(event->udev, "changing net interface name from '%s' to '%s'\n",
             udev_device_get_sysname(dev), event->name);
@@ -492,13 +493,16 @@ static int rename_netif(struct udev_event *event)
                }
 
                /* free our own name, another process may wait for us */
-               util_strscpyl(ifr.ifr_newname, IFNAMSIZ, udev_device_get_sysname(dev), "_rename", NULL);
+               newdup = strdup(ifr.ifr_newname);
+               util_strscpyl(ifr.ifr_newname, IFNAMSIZ, udev_device_get_sysname(dev), "-", newdup, NULL);
+               free(newdup);
                err = ioctl(sk, SIOCSIFNAME, &ifr);
                if (err != 0) {
                        err(event->udev, "error changing netif name %s to %s: %m\n",
                            ifr.ifr_name, ifr.ifr_newname);
                        goto exit;
                }
+               rename_netif_kernel_log(ifr);
 
                /* wait 90 seconds for our target to become available */
                util_strscpy(ifr.ifr_name, IFNAMSIZ, ifr.ifr_newname);