Driver core: notify userspace of network device renames

Provide rename event for when we rename network devices.

Signed-off-by: Jean Tourrilhes <jt@hpl.hp.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 

2 files changed, 41 insertions, 0 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
index bbbfab4145e6..db1d23707eb1 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -311,13 +311,43 @@ EXPORT_SYMBOL(kobject_set_name);
 int kobject_rename(struct kobject * kobj, const char *new_name)
 {
         int error = 0;
+        const char *devpath = NULL;
+        char *devpath_string = NULL;
+        char *envp[2];
 
         kobj = kobject_get(kobj);
         if (!kobj)
                 return -EINVAL;
         if (!kobj->parent)
                 return -EINVAL;
+
+        devpath = kobject_get_path(kobj, GFP_KERNEL);
+        if (!devpath) {
+                error = -ENOMEM;
+                goto out;
+        }
+        devpath_string = kmalloc(strlen(devpath) + 15, GFP_KERNEL);
+        if (!devpath_string) {
+                error = -ENOMEM;
+                goto out;
+        }
+        sprintf(devpath_string, "DEVPATH_OLD=%s", devpath);
+        envp[0] = devpath_string;
+        envp[1] = NULL;
+        /* Note : if we want to send the new name alone, not the full path,
+         * we could probably use kobject_name(kobj); */
+
         error = sysfs_rename_dir(kobj, kobj->parent->dentry, new_name);
+
+        /* This function is mostly/only used for network interface.
+         * Some hotplug package track interfaces by their name and
+         * therefore want to know when the name is changed by the user. */
+        if (!error)
+                kobject_uevent_env(kobj, KOBJ_MOVE, envp);
+
+out:
+        kfree(devpath_string);
+        kfree(devpath);
         kobject_put(kobj);
 
         return error;
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 221a64ab64f7..e441ec7988c1 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -424,6 +424,17 @@ static int netdev_uevent(struct device *d, char **envp,
         if ((size <= 0) || (i >= num_envp))
                 return -ENOMEM;
 
+        /* pass ifindex to uevent.
+         * ifindex is useful as it won't change (interface name may change)
+         * and is what RtNetlink uses natively. */
+        envp[i++] = buf;
+        n = snprintf(buf, size, "IFINDEX=%d", dev->ifindex) + 1;
+        buf += n;
+        size -= n;
+
+        if ((size <= 0) || (i >= num_envp))
+                return -ENOMEM;
+
         envp[i] = NULL;
         return 0;
 }