illumos: manual page: drv

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

NAME

drv_getparm - retrieve kernel state information

SYNOPSIS

#include <sys/ddi.h>

int drv_getparm(unsigned int parm, void *value_p);

INTERFACE LEVEL

Architecture independent level 1 (DDI/DKI).

PARAMETERS

parm
The kernel parameter to be obtained. Possible values are:

LBOLT
Read the value of lbolt. lbolt is a clock_t that is
unconditionally incremented by one at each clock tick. No
special treatment is applied when this value overflows the
maximum value of the signed integral type clock_t. When this
occurs, its value will be negative, and its magnitude will be
decreasing until it again passes zero. It can therefore not be
relied upon to provide an indication of the amount of time that
passes since the last system reboot, nor should it be used to
mark an absolute time in the system. Only the difference
between two measurements of lbolt is significant. It is used in
this way inside the system kernel for timing purposes.

PPGRP
Read the process group identification number. This number
determines which processes should receive a HANGUP or BREAK
signal when detected by a driver.

UPROCP
Read the process table token value.

PPID
Read process identification number.

PSID
Read process session identification number.

TIME
Read time in seconds.

UCRED
Return a pointer to the caller's credential structure.

value_p
A pointer to the data space in which the value of the
parameter is to be copied.

DESCRIPTION

Since the release of the Solaris 2.6 operating environment, the
drv_getparm() function has been replaced by ddi_get_lbolt(9F),
ddi_get_time(9F), and ddi_get_pid(9F).

The drv_getparm() function verifies that parm corresponds to a kernel
parameter that may be read. If the value of parm does not correspond to a
parameter or corresponds to a parameter that may not be read, -1 is
returned. Otherwise, the value of the parameter is stored in the data
space pointed to by value_p.

The drv_getparm() function does not explicitly check to see whether the
device has the appropriate context when the function is called and the
function does not check for correct alignment in the data space pointed
to by value_p. It is the responsibility of the driver writer to use this
function only when it is appropriate to do so and to correctly declare
the data space needed by the driver.

RETURN VALUES

The drv_getparm() function returns 0 to indicate success, -1 to indicate
failure. The value stored in the space pointed to by value_p is the value
of the parameter if 0 is returned, or undefined if -1 is returned. -1 is
returned if you specify a value other than LBOLT, PPGRP, PPID, PSID,
TIME, UCRED, or UPROCP. Always check the return code when using this
function.

CONTEXT

The drv_getparm() function can be called from user context only when
using PPGRP, PPID, PSID, UCRED, or UPROCP. It can be called from user,
interrupt, or kernel context when using the LBOLT or TIME argument.