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

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

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);

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().

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().

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

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.

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);
}

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

ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Committed
MT-Level Safe

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

Writing Device Drivers

May 15, 2008 OmniOS