DI_CHILD_NODE(3DEVINFO) Device Information Library Functions

NAME

di_child_node, di_parent_node, di_sibling_node, di_drv_first_node,
di_drv_next_node - libdevinfo node traversal functions

SYNOPSIS

cc [ flag... ] file... -ldevinfo [ library... ]
#include <libdevinfo.h>

di_node_t di_child_node(di_node_t node);


di_node_t di_parent_node(di_node_t node);


di_node_t di_sibling_node(di_node_t node);


di_node_t di_drv_first_node(const char *drv_name, di_node_t root);


di_node_t di_drv_next_node(di_node_t node);

PARAMETERS

drv_name
The name of the driver of interest.


node
A handle to any node in the snapshot.


root
The handle of the root node for the snapshot returned by
di_init(3DEVINFO).

DESCRIPTION

The kernel device configuration data may be viewed in two ways, either as
a tree of device configuration nodes or as a list of nodes associated
with each driver. In the tree view, each node may contain references to
its parent, the next sibling in a list of siblings, and the first child
of a list of children. In the per-driver view, each node contains a
reference to the next node associated with the same driver. Both views
are captured in the snapshot, and the interfaces are provided for node
access.


The di_child_node() function obtains a handle to the first child of node.
If no child node exists in the snapshot, DI_NODE_NIL is returned and
errno is set to ENXIO or ENOTSUP.


The di_parent_node() function obtains a handle to the parent node of
node. If no parent node exists in the snapshot, DI_NODE_NIL is returned
and errno is set to ENXIO or ENOTSUP.


The di_sibling_node() function obtains a handle to the next sibling node
of node. If no next sibling node exists in the snapshot, DI_NODE_NIL is
returned and errno is set to ENXIO or ENOTSUP.


The di_drv_first_node() function obtains a handle to the first node
associated with the driver specified by drv_name. If there is no such
driver, DI_NODE_NIL is returned with errno is set to EINVAL. If the
driver exists but there is no node associated with this driver,
DI_NODE_NIL is returned and errno is set to ENXIO or ENOTSUP.


The di_drv_next_node() function returns a handle to the next node bound
to the same driver. If no more nodes exist, DI_NODE_NIL is returned.

RETURN VALUES

Upon successful completion, a handle is returned. Otherwise, DI_NODE_NIL
is returned and errno is set to indicate the error.

ERRORS

These functions will fail if:

EINVAL
The argument is invalid.


ENXIO
The requested node does not exist.


ENOTSUP
The node was not found in the snapshot, but it may exist in
the kernel. This error may occur if the snapshot contains a
partial device tree.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Evolving |
+--------------------+-----------------+
|MT-Level | Safe |
+--------------------+-----------------+

SEE ALSO

di_init(3DEVINFO), libdevinfo(3LIB), attributes(7)


Writing Device Drivers

December 1, 1998 DI_CHILD_NODE(3DEVINFO)