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 data.

DINFOCPYALL

Include all of the above.

DINFOLYR

Include device layering data.

DINFOCPYONE

Include only a single node without properties or minor nodes.

phys_path

Physical path of the root 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 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(7D) 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 node names:

/*
 * Code to print all device tree 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(5) for descriptions of the following attributes:

See Also

open(2), ioctl(2), mmap(2), libdevinfo(3LIB), attributes(5)

Writing Device Drivers