DI_INIT(3DEVINFO) Device Information Library Functions DI_INIT(3DEVINFO)

NAME

di_init, di_fini - create and destroy a snapshot of kernel device tree

SYNOPSIS

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

di_node_t di_init(const char *phys_path, uint_t flags);


void di_fini(di_node_t root);

PARAMETERS

flags
Snapshot content specification. The possible values can be a
bitwise OR of at least one of the following:

DINFOSUBTREE
Include subtree.


DINFOPROP
Include properties.


DINFOMINOR
Include minor node data.


DINFOCPYALL
Include all of the above.


DINFOPATH
Include multipath path node data.


DINFOLYR
Include device layering data.


DINFOCPYONE
Include only a single node without
properties, minor nodes, or path nodes.


phys_path
Physical path of the root device node of the snapshot. See
di_devfs_path(3DEVINFO).


root
Handle obtained by calling di_init().

DESCRIPTION

The di_init() function creates a snapshot of the kernel device tree and
returns a handle of the root device node. The caller specifies the
contents of the snapshot by providing flag and phys_path.


The di_fini() function destroys the snapshot of the kernel device tree
and frees the associated memory. All handles associated with this
snapshot become invalid after the call to di_fini().

RETURN VALUES

Upon success, di_init() returns a handle. Otherwise, DI_NODE_NIL is
returned and errno is set to indicate the error.

ERRORS

The di_init() function can set errno to any error code that can also be
set by open(2), ioctl(2) or mmap(2). The most common error codes include:

EACCES
Insufficient privilege for accessing device configuration data.


ENXIO
Either the device named by phys_path is not present in the
system, or the devinfo(4D) driver is not installed properly.


EINVAL
Either phys_path is incorrectly formed or the flags argument is
invalid.

EXAMPLES

Example 1: Using the libdevinfo Interfaces To Print All Device Tree Node

Names


The following is an example using the libdevinfo interfaces to print all
device tree device node names:


/*
* Code to print all device tree device node names
*/

#include <stdio.h>
#include <libdevinfo.h>

int
prt_nodename(di_node_t node, void *arg)
{
printf("%s\n", di_node_name(node));
return (DI_WALK_CONTINUE);
}

main()
{
di_node_t root_node;
if((root_node = di_init("/", DINFOSUBTREE)) == DI_NODE_NIL) {
fprintf(stderr, "di_init() failed\n");
exit(1);
}
di_walk_node(root_node, DI_WALK_CLDFIRST, NULL, prt_nodename);
di_fini(root_node);
}

Example 2: Using the libdevinfo Interfaces To Print The Physical Path Of

SCSI Disks


The following example uses the libdevinfo interfaces to print the
physical path of SCSI disks:


/*
* Code to print physical path of scsi disks
*/

#include <stdio.h>
#include <libdevinfo.h>
#define DISK_DRIVER "sd" /* driver name */

void
prt_diskinfo(di_node_t node)
{
int instance;
char *phys_path;

/*
* If the device node exports no minor nodes,
* there is no physical disk.
*/
if (di_minor_next(node, DI_MINOR_NIL) == DI_MINOR_NIL) {
return;
}

instance = di_instance(node);
phys_path = di_devfs_path(node);
printf("%s%d: %s\n", DISK_DRIVER, instance, phys_path);
di_devfs_path_free(phys_path);
}

void
walk_disknodes(di_node_t node)
{
node = di_drv_first_node(DISK_DRIVER, node);
while (node != DI_NODE_NIL) {
prt_diskinfo(node);
node = di_drv_next_node(node);
}
}

main()
{
di_node_t root_node;
if ((root_node = di_init("/", DINFOCPYALL)) == DI_NODE_NIL) {
fprintf(stderr, "di_init() failed\n");
exit(1);
}
walk_disknodes(root_node);
di_fini(root_node);
}

ATTRIBUTES

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


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

SEE ALSO

ioctl(2), mmap(2), open(2), libdevinfo(3LIB), attributes(7)


Writing Device Drivers

May 15, 2008 DI_INIT(3DEVINFO)