static long evtchn_ioctl()

in evtchn.c [429:597]

• 134 lines of code
• 30 McCabe index (conditional complexity)

static long evtchn_ioctl(struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	int rc;
	struct per_user_data *u = file->private_data;
	void __user *uarg = (void __user *) arg;

	/* Prevent bind from racing with unbind */
	mutex_lock(&u->bind_mutex);

	switch (cmd) {
	case IOCTL_EVTCHN_BIND_VIRQ: {
		struct ioctl_evtchn_bind_virq bind;
		struct evtchn_bind_virq bind_virq;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		bind_virq.virq = bind.virq;
		bind_virq.vcpu = xen_vcpu_nr(0);
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
						 &bind_virq);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, bind_virq.port);
		if (rc == 0)
			rc = bind_virq.port;
		break;
	}

	case IOCTL_EVTCHN_BIND_INTERDOMAIN: {
		struct ioctl_evtchn_bind_interdomain bind;
		struct evtchn_bind_interdomain bind_interdomain;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID &&
		    u->restrict_domid != bind.remote_domain)
			break;

		bind_interdomain.remote_dom  = bind.remote_domain;
		bind_interdomain.remote_port = bind.remote_port;
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
						 &bind_interdomain);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, bind_interdomain.local_port);
		if (rc == 0)
			rc = bind_interdomain.local_port;
		break;
	}

	case IOCTL_EVTCHN_BIND_UNBOUND_PORT: {
		struct ioctl_evtchn_bind_unbound_port bind;
		struct evtchn_alloc_unbound alloc_unbound;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		alloc_unbound.dom        = DOMID_SELF;
		alloc_unbound.remote_dom = bind.remote_domain;
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
						 &alloc_unbound);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, alloc_unbound.port);
		if (rc == 0)
			rc = alloc_unbound.port;
		break;
	}

	case IOCTL_EVTCHN_UNBIND: {
		struct ioctl_evtchn_unbind unbind;
		struct user_evtchn *evtchn;

		rc = -EFAULT;
		if (copy_from_user(&unbind, uarg, sizeof(unbind)))
			break;

		rc = -EINVAL;
		if (unbind.port >= xen_evtchn_nr_channels())
			break;

		rc = -ENOTCONN;
		evtchn = find_evtchn(u, unbind.port);
		if (!evtchn)
			break;

		disable_irq(irq_from_evtchn(unbind.port));
		evtchn_unbind_from_user(u, evtchn);
		rc = 0;
		break;
	}

	case IOCTL_EVTCHN_NOTIFY: {
		struct ioctl_evtchn_notify notify;
		struct user_evtchn *evtchn;

		rc = -EFAULT;
		if (copy_from_user(&notify, uarg, sizeof(notify)))
			break;

		rc = -ENOTCONN;
		evtchn = find_evtchn(u, notify.port);
		if (evtchn) {
			notify_remote_via_evtchn(notify.port);
			rc = 0;
		}
		break;
	}

	case IOCTL_EVTCHN_RESET: {
		/* Initialise the ring to empty. Clear errors. */
		mutex_lock(&u->ring_cons_mutex);
		spin_lock_irq(&u->ring_prod_lock);
		WRITE_ONCE(u->ring_cons, 0);
		WRITE_ONCE(u->ring_prod, 0);
		u->ring_overflow = 0;
		spin_unlock_irq(&u->ring_prod_lock);
		mutex_unlock(&u->ring_cons_mutex);
		rc = 0;
		break;
	}

	case IOCTL_EVTCHN_RESTRICT_DOMID: {
		struct ioctl_evtchn_restrict_domid ierd;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&ierd, uarg, sizeof(ierd)))
		    break;

		rc = -EINVAL;
		if (ierd.domid == 0 || ierd.domid >= DOMID_FIRST_RESERVED)
			break;

		u->restrict_domid = ierd.domid;
		rc = 0;

		break;
	}

	default:
		rc = -ENOSYS;
		break;
	}
	mutex_unlock(&u->bind_mutex);

	return rc;
}