Re: [PATCH 009 of 9] knfsd: Allow sockets to be passed to nfsd via 'portlist'
- From: Andrew Morton <akpm@xxxxxxxx>
- Date: Tue, 25 Jul 2006 23:53:09 -0700
On Tue, 25 Jul 2006 11:55:08 +1000
NeilBrown <neilb@xxxxxxx> wrote:
Userspace should create and bind a socket (but not connectted)
and write the 'fd' to portlist. This will cause the nfs server
to listen on that socket.
To close a socket, the name of the socket - as read from 'portlist'
can be written to 'portlist' with a preceding '-'.
ick. Is that the best API we can come up with?
It's a privileged operation, but heck. Do we perform validation on the fd
to make sure that it's refers to a socket and not to /dev/fb0?
static ssize_t write_ports(struct file *file, char *buf, size_t size)
{
- /* for now, ignore what was written and just
- * return known ports
- * AF proto address port
+ if (size == 0) {
+ int len = 0;
+ lock_kernel();
+ if (nfsd_serv)
+ len = svc_sock_names(buf, nfsd_serv, NULL);
+ unlock_kernel();
+ return len;
+ }
+ /* Either a single 'fd' number is written, in which
+ * case it must be for a socket of a supported family/protocol,
+ * and we use it as an nfsd socket, or
+ * A '-' followed by the 'name' of a socket in which case
+ * we close the socket.
*/
- int len = 0;
- lock_kernel();
- if (nfsd_serv)
- len = svc_sock_names(buf, nfsd_serv);
- unlock_kernel();
- return len;
+ if (isdigit(buf[0])) {
+ char *mesg = buf;
+ int fd;
+ int err;
+ err = get_int(&mesg, &fd);
+ if (err)
+ return -EINVAL;
+ if (fd < 0)
+ return -EINVAL;
+ err = nfsd_create_serv();
+ if (!err) {
+ int proto = 0;
+ err = svc_addsock(nfsd_serv, fd, buf, &proto);
+ /* Decrease the count, but don't shutdown the
+ * the service
+ */
+ if (err >= 0)
+ lockd_up(proto);
+ nfsd_serv->sv_nrthreads--;
+ }
+ return err;
+ }
+ if (buf[0] == '-') {
+ char *toclose = kstrdup(buf+1, GFP_KERNEL);
+ int len = 0;
+ if (!toclose)
+ return -ENOMEM;
+ lock_kernel();
+ if (nfsd_serv)
+ len = svc_sock_names(buf, nfsd_serv, toclose);
+ unlock_kernel();
+ kfree(toclose);
+ return len;
+ }
+ return -EINVAL;
}
<checks>
OK, simple_transaction_get() guarantees that *buf is null-terminated. It
might be worth a comment to stop code-reviewers from freaking out ;)
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- References:
- [PATCH 000 of 9] knfsd: Introduction
- From: NeilBrown
- [PATCH 009 of 9] knfsd: Allow sockets to be passed to nfsd via 'portlist'
- From: NeilBrown
- [PATCH 000 of 9] knfsd: Introduction
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