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

From: Alexey Dobriyan
Date: Tue Mar 20 2007 - 08:50:50 EST


On 3/20/07, Keiichi KII <k-keiichi@xxxxxxxxxxxxx> 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.
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