Re: [RFC][PATCH -mm take3 6/6][resend] add ioctls for adding/removing target

["Alexey Dobriyan" <adobriyan@gmail.com>]

On 3/20/07, Keiichi KII <k-keiichi@bx.jp.nec.com> wrote:
> We add ioctls for adding/removing target.
> If we use NETCONSOLE_ADD_TARGET ioctl,
> we can dynamically add netconsole target.
> If we use NETCONSOLE_REMOVE_TARGET ioctl,
> we can dynamically remoe netconsole target.
>
> We attach a sample program for ioctl.

> +static int netconsole_ioctl(struct inode *inode, struct file *file,
> +			    unsigned int cmd, unsigned long arg)
> +{
> +	int id, count;
> +	char config[256];
> +	char *cur;
> +	struct netconsole_request req;
> +	struct netconsole_target *nt, *tmp;
> +	void __user *argp = (void __user *)arg;
> +
> +	switch (cmd) {
> +	case NETCON_ADD_TARGET:
> +		printk(KERN_INFO "netconsole: cmd=NETCON_ADD_TARGET\n");
> +		if (copy_from_user(&req, argp, sizeof(req)))
> +			return -EFAULT;
> +		cur = config;
> +		count = sprintf(cur, "%d@", req.local_port);
> +		cur += count;
> +		if (req.local_ip)
> +			count = sprintf(cur, "%d.%d.%d.%d/",
> +					NIPQUAD(req.local_ip));
> +		else
> +			count = sprintf(cur, "/");
> +		cur += count;
> +		count = sprintf(cur, "%s,", req.netdev_name);
> +		cur += count;
> +		count = sprintf(cur, "%d@", req.remote_port);
> +		cur += count;
> +		count = sprintf(cur, "%d.%d.%d.%d/",
> +				NIPQUAD(req.remote_ip));
> +		cur += count;
> +		count = sprintf(cur, "%02x:%02x:%02x:%02x:%02x:%02x",
> +				req.remote_mac[0], req.remote_mac[1],
> +				req.remote_mac[2], req.remote_mac[3],
> +				req.remote_mac[4], req.remote_mac[5]);
> +		printk(KERN_INFO "count = %d config=[%s]\n", count, config);
> +		if (add_target(config))
> +			return -EINVAL;
> +		break;
> +	case NETCON_REMOVE_TARGET:
> +		printk(KERN_INFO "netconsole: cmd=NETCON_REMOVE_TARGET\n");
> +		if (copy_from_user(&id, argp, sizeof(int)))
> +			return -EFAULT;
> +		printk(KERN_INFO "netconsole: id=%d\n", id);
> +		list_for_each_entry_safe(nt, tmp, &target_list, list) {
> +			if (nt->id == id) {
> +				kobject_unregister(&nt->obj);
> +				break;
> +			}
> +		}
> +		break;
> +	default:
> +		return -ENOTTY;
> +	}
> +
> +	return 0;
> +}

If you go with misc device, then implement ->write method so you, say,
do

     echo "add [same format as with module parameter]" >/dev/netconsole

and avoid all that additional programs and ioctls.