int
xenbus_watch_path(device_t dev, char *path, struct xs_watch *watch,
xs_watch_cb_t *callback, uintptr_t callback_data)
{
int error;
watch->node = path;
watch->callback = callback;
watch->callback_data = callback_data;
error = xs_register_watch(watch);
if (error) {
watch->node = NULL;
watch->callback = NULL;
xenbus_dev_fatal(dev, error, "adding watch on %s", path);
}
return (error);
}
/**
* \brief Verify the existance of attached device instances and perform
* probe/attach processing for newly arrived devices.
*
* \param dev The NewBus device representing this XenBus bus.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*/
static int
xenbusb_probe_children(device_t dev)
{
device_t *kids;
struct xenbus_device_ivars *ivars;
int i, count, error;
if (device_get_children(dev, &kids, &count) == 0) {
for (i = 0; i < count; i++) {
if (device_get_state(kids[i]) != DS_NOTPRESENT) {
/*
* We already know about this one.
* Make sure it's still here.
*/
xenbusb_verify_device(dev, kids[i]);
continue;
}
error = device_probe_and_attach(kids[i]);
if (error == ENXIO) {
struct xenbusb_softc *xbs;
/*
* We don't have a PV driver for this device.
* However, an emulated device we do support
* may share this backend. Hide the node from
* XenBus until the next rescan, but leave it's
* state unchanged so we don't inadvertently
* prevent attachment of any emulated device.
*/
xenbusb_delete_child(dev, kids[i]);
/*
* Since the XenStore state of this device
* still indicates a pending attach, manually
* release it's hold on the boot process.
*/
xbs = device_get_softc(dev);
xenbusb_release_confighook(xbs);
continue;
} else if (error) {
/*
* Transition device to the closed state
* so the world knows that attachment will
* not occur.
*/
xenbus_set_state(kids[i], XenbusStateClosed);
/*
* Remove our record of this device.
* So long as it remains in the closed
* state in the XenStore, we will not find
* it again. The state will only change
* if the control domain actively reconfigures
* this device.
*/
xenbusb_delete_child(dev, kids[i]);
continue;
}
/*
* Augment default newbus provided dynamic sysctl
* variables with the standard ivar contents of
* XenBus devices.
*/
xenbusb_device_sysctl_init(kids[i]);
/*
* Now that we have a driver managing this device
* that can receive otherend state change events,
* hook up a watch for them.
*/
ivars = device_get_ivars(kids[i]);
xs_register_watch(&ivars->xd_otherend_watch);
xs_register_watch(&ivars->xd_local_watch);
}
free(kids, M_TEMP);
}
return (0);
}