vlan: initialize device ifname earlier at creation time

Avoids attempting to add the device with an empty string as ifname

Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/vlan.c b/vlan.c
index 8748b3040d511f554ec335071f39b4b0a120df63..6270d95d755de7caa55dae420f2aa8379e83372b 100644 (file)
--- a/vlan.c
+++ b/vlan.c
@@ -61,19 +61,9 @@ static int vlan_set_device_state(struct device *dev, bool up)
        return ret;
 }
 
-static int vlan_dev_set_name(struct vlan_device *vldev, struct device *dev)
-{
-       char *name;
-
-       name = alloca(strlen(dev->ifname) + sizeof(".2147483647\0"));
-       vldev->dev.hidden = dev->hidden;
-       sprintf(name, "%s.%d", dev->ifname, vldev->id);
-
-       return device_set_ifname(&vldev->dev, name);
-}
-
 static void vlan_dev_cb(struct device_user *dep, enum device_event ev)
 {
+       char name[IFNAMSIZ + 1];
        struct vlan_device *vldev;
 
        vldev = container_of(dep, struct vlan_device, dep);
@@ -85,7 +75,10 @@ static void vlan_dev_cb(struct device_user *dep, enum device_event ev)
                device_set_present(&vldev->dev, false);
                break;
        case DEV_EVENT_UPDATE_IFNAME:
-               if (vlan_dev_set_name(vldev, dep->dev) < 0)
+               vldev->dev.hidden = dep->dev->hidden;
+               if (snprintf(name, sizeof(name), "%s.%d", dep->dev->ifname,
+                            vldev->id) >= sizeof(name) - 1 ||
+                   device_set_ifname(&vldev->dev, name))
                        free_vlan_if(&vldev->dev);
                break;
        case DEV_EVENT_TOPO_CHANGE:
@@ -106,6 +99,7 @@ static struct device *get_vlan_device(struct device *dev, int id, bool create)
        };
        struct vlan_device *vldev;
        struct device_user *dep;
+       char name[IFNAMSIZ + 1];
 
        /* look for an existing interface before creating a new one */
        list_for_each_entry(dep, &dev->users.list, list.list) {
@@ -122,20 +116,22 @@ static struct device *get_vlan_device(struct device *dev, int id, bool create)
        if (!create)
                return NULL;
 
-       D(DEVICE, "Create vlan device '%s.%d'\n", dev->ifname, id);
+       if (snprintf(name, sizeof(name), "%s.%d", dev->ifname, id) >= sizeof(name) - 1)
+               return NULL;
+
+       D(DEVICE, "Create vlan device '%s'\n", name);
 
        vldev = calloc(1, sizeof(*vldev));
        if (!vldev)
                return NULL;
 
        vldev->id = id;
+       vldev->dev.hidden = dev->hidden;
+       strcpy(vldev->dev.ifname, name);
 
        if (device_init(&vldev->dev, &vlan_type, NULL) < 0)
                goto error;
 
-       if (vlan_dev_set_name(vldev, dev) < 0)
-               goto error;
-
        vldev->dev.default_config = true;
 
        vldev->set_state = vldev->dev.set_state;