/**
* \brief Backend XenBus method implementing responses to local
* XenStore changes.
*
* \param bus The XenBus bus parent of child.
* \param child The XenBus child whose peer stat has changed.
* \param_path The tree relative sub-path to the modified node. The empty
* string indicates the root of the tree was destroyed.
*/
static void
xenbusb_back_localend_changed(device_t bus, device_t child, const char *path)
{
xenbusb_localend_changed(bus, child, path);
if (strcmp(path, "/state") != 0
&& strcmp(path, "/online") != 0)
return;
if (xenbus_get_state(child) != XenbusStateClosed
|| xenbus_dev_is_online(child) != 0)
return;
/*
* Cleanup the hotplug entry in the XenStore if
* present. The control domain expects any userland
* component associated with this device to destroy
* this node in order to signify it is safe to
* teardown the device. However, not all backends
* rely on userland components, and those that
* do should either use a communication channel
* other than the XenStore, or ensure the hotplug
* data is already cleaned up.
*
* This removal ensures that no matter what path
* is taken to mark a back-end closed, the control
* domain will understand that it is closed.
*/
xs_rm(XST_NIL, xenbus_get_node(child), "hotplug-status");
}
/**
* Handler for all generic XenBus device systcl nodes.
*/
static int
xenbusb_device_sysctl_handler(SYSCTL_HANDLER_ARGS)
{
device_t dev;
const char *value;
dev = (device_t)arg1;
switch (arg2) {
case XENBUS_IVAR_NODE:
value = xenbus_get_node(dev);
break;
case XENBUS_IVAR_TYPE:
value = xenbus_get_type(dev);
break;
case XENBUS_IVAR_STATE:
value = xenbus_strstate(xenbus_get_state(dev));
break;
case XENBUS_IVAR_OTHEREND_ID:
return (sysctl_handle_int(oidp, NULL,
xenbus_get_otherend_id(dev),
req));
/* NOTREACHED */
case XENBUS_IVAR_OTHEREND_PATH:
value = xenbus_get_otherend_path(dev);
break;
default:
return (EINVAL);
}
return (SYSCTL_OUT_STR(req, value));
}
/**
* \brief Backend XenBus method implementing responses to peer state changes.
*
* \param bus The XenBus bus parent of child.
* \param child The XenBus child whose peer stat has changed.
* \param state The current state of the peer.
*/
static void
xenbusb_back_otherend_changed(device_t bus, device_t child,
enum xenbus_state peer_state)
{
/* Perform default processing of state. */
xenbusb_otherend_changed(bus, child, peer_state);
/*
* "Online" devices are never fully detached in the
* newbus sense. Only the front<->back connection is
* torn down. If the front returns to the initialising
* state after closing a previous connection, signal
* our willingness to reconnect and that all necessary
* XenStore data for feature negotiation is present.
*/
if (peer_state == XenbusStateInitialising
&& xenbus_dev_is_online(child) != 0
&& xenbus_get_state(child) == XenbusStateClosed)
xenbus_set_state(child, XenbusStateInitWait);
}
