illumos: manual page: ddi_prop

DDI_PROP_LOOKUP(9F) Kernel Functions for Drivers DDI_PROP_LOOKUP(9F)

NAME

ddi_prop_lookup, ddi_prop_lookup_int_array, ddi_prop_lookup_int64_array,
ddi_prop_lookup_string_array, ddi_prop_lookup_string,
ddi_prop_lookup_byte_array, ddi_prop_free - look up property information

SYNOPSIS

#include <sys/ddi.h>
#include <sys/sunddi.h>

int ddi_prop_lookup_int_array(dev_t match_dev, dev_info_t *dip,
uint_t flags, char *name, int **datap, uint_t *nelementsp);

int ddi_prop_lookup_int64_array(dev_t match_dev, dev_info_t *dip,
uint_t flags, char *name, int64_t **datap, uint_t *nelementsp);

int ddi_prop_lookup_string_array(dev_t match_dev, dev_info_t *dip,
uint_t flags, char *name, char ***datap, uint_t *nelementsp);

int ddi_prop_lookup_string(dev_t match_dev, dev_info_t *dip, uint_t flags,
char *name, char **datap);

int ddi_prop_lookup_byte_array(dev_t match_dev, dev_info_t *dip,
uint_t flags, char *name, uchar_t **datap, uint_t *nelementsp);

void ddi_prop_free(void *data);

PARAMETERS

match_dev
Device number associated with property or DDI_DEV_T_ANY.

dip
Pointer to the device info node of device whose property
list should be searched.

flags
Possible flag values are some combination of:

DDI_PROP_DONTPASS
Do not pass request to parent device
information node if the property is
not found.

DDI_PROP_NOTPROM
Do not look at PROM properties
(ignored on platforms that do not
support PROM properties).

name
String containing the name of the property.

nelementsp
The address of an unsigned integer which, upon successful
return, will contain the number of elements accounted for
in the memory pointed at by datap. The elements are either
integers, strings or bytes depending on the interface used.

datap

ddi_prop_lookup_int_array()

The address of a pointer to an array of integers which,
upon successful return, will point to memory containing
the integer array property value.

ddi_prop_lookup_int64_array()

The address of a pointer to an array of 64-bit integers
which, upon successful return, will point to memory
containing the integer array property value.

ddi_prop_lookup_string_array()

The address of a pointer to an array of strings which,
upon successful return, will point to memory containing
the array of strings. The array of strings is formatted
as an array of pointers to NULL terminated strings,
much like the argv argument to execve(2).

ddi_prop_lookup_string()

The address of a pointer to a string which, upon
successful return, will point to memory containing the
NULL terminated string value of the property.

ddi_prop_lookup_byte_array()

The address of pointer to an array of bytes which, upon
successful return, will point to memory containing the
byte array value of the property.

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

DESCRIPTION

The property look up routines search for and, if found, return the value
of a given property. Properties are searched for based on the dip, name,
match_dev, and the type of the data (integer, string, or byte). The
property search order is as follows:

1. Search software properties created by the driver.

2. Search the software properties created by the system (or nexus
nodes in the device info tree).

3. Search the driver global properties list.

4. If DDI_PROP_NOTPROM is not set, search the PROM properties (if
they exist).

5. If DDI_PROP_DONTPASS is not set, pass this request to the
parent device information node.

6. Return DDI_PROP_NOT_FOUND.

Usually, the match_dev argument should be set to the actual device number
that this property is associated with. However, if the match_dev argument
is DDI_DEV_T_ANY, the property look up routines will match the request
regardless of the actual match_dev the property was created with. If a
property was created with match_dev set to DDI_DEV_T_NONE, then the only
way to look up this property is with a match_dev set to DDI_DEV_T_ANY.
PROM properties are always created with match_dev set to DDI_DEV_T_NONE.

name must always be set to the name of the property being looked up.

For the routines ddi_prop_lookup_int_array(),
ddi_prop_lookup_int64_array(), ddi_prop_lookup_string_array(),
ddi_prop_lookup_string(), and ddi_prop_lookup_byte_array(), datap is the
address of a pointer which, upon successful return, will point to memory
containing the value of the property. In each case *datap points to a
different type of property value. See the individual descriptions of the
routines below for details on the different return values. nelementsp is
the address of an unsigned integer which, upon successful return, will
contain the number of integer, string or byte elements accounted for in
the memory pointed at by *datap.

All of the property look up routines may block to allocate memory needed
to hold the value of the property.

When a driver has obtained a property with any look up routine and is
finished with that property, it must be freed by calling ddi_prop_free().
ddi_prop_free() must be called with the address of the allocated
property. For instance, if one called ddi_prop_lookup_int_array() with
datap set to the address of a pointer to an integer, &my_int_ptr, then
the companion free call would be ddi_prop_free(my_int_ptr).

ddi_prop_lookup_int_array()

This routine searches for and returns an array of integer property
values. An array of integers is defined to *nelementsp number of 4
byte long integer elements. datap should be set to the address of a
pointer to an array of integers which, upon successful return, will
point to memory containing the integer array value of the property.

ddi_prop_lookup_int64_array()

This routine searches for and returns an array of 64-bit integer
property values. The array is defined to be *nelementsp number of
int64_t elements. datap should be set to the address of a pointer to
an array of int64_t's which, upon successful return, will point to
memory containing the integer array value of the property. This
routine will not search the PROM for 64-bit property values.

ddi_prop_lookup_string_array()

This routine searches for and returns a property that is an array of
strings. datap should be set to address of a pointer to an array of
strings which, upon successful return, will point to memory
containing the array of strings. The array of strings is formatted
as an array of pointers to null-terminated strings, much like the
argv argument to execve(2).

ddi_prop_lookup_string()

This routine searches for and returns a property that is a null-
terminated string. datap should be set to the address of a pointer to
string which, upon successful return, will point to memory containing
the string value of the property.

ddi_prop_lookup_byte_array()

This routine searches for and returns a property that is an array of
bytes. datap should be set to the address of a pointer to an array
of bytes which, upon successful return, will point to memory
containing the byte array value of the property.

ddi_prop_free()

Frees the resources associated with a property previously allocated
using ddi_prop_lookup_int_array(), ddi_prop_lookup_int64_array(),
ddi_prop_lookup_string_array(), ddi_prop_lookup_string(), or
ddi_prop_lookup_byte_array().

RETURN VALUES

The functions ddi_prop_lookup_int_array(), ddi_prop_lookup_int64_array(),
ddi_prop_lookup_string_array(), ddi_prop_lookup_string(), and
ddi_prop_lookup_byte_array() return the following values:

DDI_PROP_SUCCESS
Upon success.

DDI_PROP_INVAL_ARG
If an attempt is made to look up a property
with match_dev equal to DDI_DEV_T_NONE, name is
NULL or name is the null string.

DDI_PROP_NOT_FOUND
Property not found.

DDI_PROP_UNDEFINED
Property explicitly not defined (see
ddi_prop_undefine(9F)).

DDI_PROP_CANNOT_DECODE
The value of the property cannot be decoded.

CONTEXT

These functions can be called from user or kernel context.

EXAMPLES

Example 1: Using ddi_prop_lookup_int_array()

The following example demonstrates the use of
ddi_prop_lookup_int_array().

int *options;
int noptions;

/*
* Get the data associated with the integer "options" property
* array, along with the number of option integers
*/
if (ddi_prop_lookup_int_array(DDI_DEV_T_ANY, xx_dip, 0,
"options", &options, &noptions) == DDI_PROP_SUCCESS) {
/*
* Do "our thing" with the options data from the property
*/
xx_process_options(options, noptions);

/*
* Free the memory allocated for the property data
*/
ddi_prop_free(options);
}