/**
* \brief XenStore watch callback for the root node of the XenStore
* subtree representing a XenBus.
*
* This callback performs, or delegates to the xbs_probe_children task,
* all processing necessary to handle dynmaic device arrival and departure
* events from a XenBus.
*
* \param watch The XenStore watch object associated with this callback.
* \param vec The XenStore watch event data.
* \param len The number of fields in the event data stream.
*/
static void
xenbusb_devices_changed(struct xs_watch *watch, const char **vec,
unsigned int len)
{
struct xenbusb_softc *xbs;
device_t dev;
char *node;
char *bus;
char *type;
char *id;
char *p;
u_int component;
xbs = (struct xenbusb_softc *)watch->callback_data;
dev = xbs->xbs_dev;
if (len <= XS_WATCH_PATH) {
device_printf(dev, "xenbusb_devices_changed: "
"Short Event Data.\n");
return;
}
node = strdup(vec[XS_WATCH_PATH], M_XENBUS);
p = strchr(node, '/');
if (p == NULL)
goto out;
bus = node;
*p = 0;
type = p + 1;
p = strchr(type, '/');
if (p == NULL)
goto out;
*p++ = 0;
/*
* Extract the device ID. A device ID has one or more path
* components separated by the '/' character.
*
* e.g. "<frontend vm id>/<frontend dev id>" for backend devices.
*/
id = p;
for (component = 0; component < xbs->xbs_id_components; component++) {
p = strchr(p, '/');
if (p == NULL)
break;
p++;
}
if (p != NULL)
*p = 0;
if (*id != 0 && component >= xbs->xbs_id_components - 1) {
xenbusb_add_device(xbs->xbs_dev, type, id);
taskqueue_enqueue(taskqueue_thread, &xbs->xbs_probe_children);
}
out:
free(node, M_XENBUS);
}
/**
* \brief Enumerate all devices of the given type on this bus.
*
* \param dev NewBus device_t for this XenBus backend bus instance.
* \param type String indicating the device sub-tree (e.g. "vfb", "vif")
* to enumerate.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*
* Devices that are found are entered into the NewBus hierarchy via
* xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects
* and ignores duplicate devices, so it can be called unconditionally
* for any device found in the XenStore.
*
* The backend XenStore hierarchy has the following format:
*
* backend/<device type>/<frontend vm id>/<device id>
*
*/
static int
xenbusb_back_enumerate_type(device_t dev, const char *type)
{
struct xenbusb_softc *xbs;
const char **vms;
u_int vm_idx;
u_int vm_count;
int error;
xbs = device_get_softc(dev);
error = xs_directory(XST_NIL, xbs->xbs_node, type, &vm_count, &vms);
if (error)
return (error);
for (vm_idx = 0; vm_idx < vm_count; vm_idx++) {
struct sbuf *vm_path;
const char *vm;
const char **devs;
u_int dev_idx;
u_int dev_count;
vm = vms[vm_idx];
vm_path = xs_join(type, vm);
error = xs_directory(XST_NIL, xbs->xbs_node, sbuf_data(vm_path),
&dev_count, &devs);
sbuf_delete(vm_path);
if (error)
break;
for (dev_idx = 0; dev_idx < dev_count; dev_idx++) {
const char *dev_num;
struct sbuf *id;
dev_num = devs[dev_idx];
id = xs_join(vm, dev_num);
xenbusb_add_device(dev, type, sbuf_data(id));
sbuf_delete(id);
}
free(devs, M_XENSTORE);
}
free(vms, M_XENSTORE);
return (0);
}
/**
* \brief Enumerate all devices of the given type on this bus.
*
* \param dev NewBus device_t for this XenBus front bus instance.
* \param type String indicating the device sub-tree (e.g. "vfb", "vif")
* to enumerate.
*
* \return On success, 0. Otherwise an errno value indicating the
* type of failure.
*
* Devices that are found are entered into the NewBus hierarchy via
* xenbusb_add_device(). xenbusb_add_device() ignores duplicate detects
* and ignores duplicate devices, so it can be called unconditionally
* for any device found in the XenStore.
*/
int
xenbusb_front_enumerate_type(device_t dev, const char *type)
{
struct xenbusb_softc *xbs;
const char **dir;
unsigned int i, count;
int error;
xbs = device_get_softc(dev);
error = xs_directory(XST_NIL, xbs->xbs_node, type, &count, &dir);
if (error)
return (error);
for (i = 0; i < count; i++)
xenbusb_add_device(dev, type, dir[i]);
free(dir, M_XENSTORE);
return (0);
}